MEE09:57

A COMPARATIVE STUDYOF

UMTS/WCDMA AND WiMAX

TECHNOLOGIES

MASTER THESIS REPORT BY: MUHAMMAD UMAIR ASLAM, ARIF HUSSAIN, SALAHUDDIN

BLEKINGE TEKNISKA HÖGSKOLA ‐ BTH

i

A COMPARATIVE STUDY OF UMTS/WCDMA AND

WIMAX TECHNOLOGIES

This thesis is submitted to the Department of Telecommunications, School of Engineering at Blekinge Institute of Technology in partial fulfillment of the requirements for the degree of Master of Science in Electrical Engineering

MUHAMMAD UMAIR ASLAM

ARIF HUSSAIN

SALAHUDDIN

Blekinge Institute of Technology

June 2009

Blekinge Institute of Technology

School of Engineering

Department of Telecommunications

Examiner: Prof. Dr. Adrian Popescu

Supervisor: Dr.Alexandru Popescu

ii

iii

ABSTRACT

The field of mobile broadband in wireless communication systems is increasingly facing the challenges of the provision of high data rates, improved seamless connectivity and broadband internet services. UMTS/WCDMDA which is a third generation wireless mobile cellular technology has been adopted in most parts of the world and now undergoing a phase of evolution and will be emerged soon as LTE. On the other hand, WiMAX which is also some times called as fourth generation mobile broadband technology is likely to be accepted in many places. With higher data rates for transmission, adaptive modulation and coding, OFDMA based physical layer and a very flexible architecture, WiMAX appears to be suppressing UMTS soon. However, the Long Term Evolution (LTE) of 3G or UMTS is likely to compete the WiMAX both technically and economically. This research provides a comparative interpretation of architecture, salient features, robustness, physical layer, mobility, capacity and coverage aspects of the both UMTS/WCDMA and WiMAX broadband technologies. It also explains the error probabilities in transmission for modulation techniques employed in both technologies. MATLAB simulations are provided in the simulation part of this report to further elaborate the differences in the two technologies in some respects. Simulation results show that the more suitability and effectively of performance for WiMAX. This research helps developing a better understanding for operators and users to make a choice in preferring any of the technologies regarding different features. Based on the study and simulation results of the key features related to capacity and fading of both technologies, we investigate the more suitability of any of the two technologies in terms of better quality and lower error rate in all IP environments.

iv

ACKNOWLEGEMENTS

Praise and glory be to ALLAH, the Lord, benefactor and cherisher of the entire world. We are grateful to over Almighty ALLAH for providing us with the knowledge, skills and capability to complete this research successfully.

Our knowledge of the field has been raised significantly and remarkably during the whole course of this Master Thesis completion. It has indeed motivated us to explore more facts and obtain increased knowledge in the field of Telecommunications and we would like to continue the research in future. The role of the university and the department has been very important and helpful for us during the whole period of research. All faculty members especially Mr. MikaelAsman, the program manager of Electrical Engineering Program, have always been kind and cooperative to us for which we are really very thank full.

We would like express our especial gratitude and regards to Mr.Alexandru Popescu our project supervisor for his tremendous support and guidance. He has always been a source of inspiration for us.

We are also very thankful to all of our friends and family members for their continuous and everlasting love, attention and moral support. We are also very grateful to all fellows at BTH who helped us morally and academically in every hour of need.

Muhammad Umair Aslam, Arif Hussain & Salahuddin

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Table of Contents BLEKINGE TEKNISKA HÖGSKOLA ‐ BTH ...... i

A COMPARATIVE STUDY OF UMTS/WCDMA AND WIMAX TECHNOLOGIES...... ii

ABSTRACT...... iv

ACKNOWLEGEMENTS ...... v

LIST OF FIGURES...... xii

LIST OF TABLES...... xv

Chapter1 ...... 1

INTRODUCTION...... 1

1.1 Thesis Layout and Short Description of Chapters...... 5 1.1.1 Chapter 2...... 5 1.1.2 Chapter 3...... 5 1.1.3 Chapter 4...... 5 1.1.4 Chapter 5...... 5 1.1.5 Chapter 6...... 6 Chapter 2 ...... 7

UNIVERSAL MOBILE TELECOMMUNICATIONS SYSTEM (UMTS)...... 7

2.1 Introduction ...... 7 2.2 Why UMTS ...... 8 2.3 Evolution of UMTS/WCDMA...... 8 2.3.1 System Evolution...... 9 2.4 WCDMA...... 10 Chapter 2 ...... 1

2.4.1 Some Significant characteristics of WCDMA ...... 11 2.5 Architecture of UMTS Network...... 12 2.5.1 User Equipment Domain...... 13

vi

2.5.2 Mobile Equipment (ME)...... 13 2.5.4 Infrastructure Domain ...... 13 2.5.4.1 Home Network (HN) ...... 14 2.5.4.2 Service Network (SN) ...... 14 2.5.4.3 Transit Network (TN)...... 14 2.6 Universal Terrestrial Radio Access Network (UTRAN) ...... 14 2.6.1 Operation Mode of UTRAN...... 14 2.6.1.1 UTRAN FDD (Frequency Division Duplex) ...... 15 2.6.1.2 UTRAN TDD (Time division Duplex) ...... 15 2.7 Core Network...... 16 2.7.1 CS Domain...... 16 2.7.2 PS Domain ...... 16 2.7.3. Mobile Switching Centre (MSC): ...... 18 2.7.4. Mobile Station (MS) ...... 18 2.7.5. Home Location Register (HLR) ...... 18 2.7.6. Visitor Location Register (VLR):...... 18 2.7.7. Authentication Center (AuC)...... 18 2.7.8. Gateway MSc (GMSC) ...... 18 2.7.9. Serving GPRS Support Node...... 19 2.7.10. Gateway GPRS Support Node ...... 19 2.8 Description of UMTS Radio Interface...... 19 2.8.1 Logical channels ...... 20 2.8.1.1 Control logical channels...... 20 2.8.1.2 Traffic logical channels...... 21 2.8.2. Transport Channels...... 21 2.9 Physical Layer...... 24 2.9.1 Spread Spectrum...... 24 2.9.1.1Channelization ...... 25 2.9.1.2 Scrambling...... 25 2.9.2 Cell Structure ...... 25 2.9.3. Cell State ...... 27 vii

2.9.4. Capacity...... 27 2.9.5. Duplex Method ...... 27 2.9.6. Multipath diversity...... 27 2.9.7 Power Control ...... 28 2.10. UMTS MAC Layer ...... 30 2.11UMTS RLC Layer ...... 30 2.12 Handovers in UMTS...... 31 2.13.1. Types of Handovers in UMTS...... 32 2.13.1.1. Vertical Handovers:...... 32 2.13.1.2. Horizontal Handovers: ...... 32 2.13.1.3. Intra‐System Handovers: ...... 32 2.13.1.4. Inter‐System Handovers: ...... 32 2.13.1.5. Hard Handovers: ...... 33 2.13.1.6. Soft Handovers:...... 33 2.13.1.7. Softer Handovers: ...... 34 2.14 UMTS Services...... 35 Chapter 3 ...... 36

WiMAX ...... 36

3.1 Introduction ...... 36 3.2 Background ...... 36 3.3 Evolution of WiMAX...... 37 3.3.1 IEEE802.16‐2001 ...... 37 3.3.2 IEEE802.16a‐2003 ...... 38 3.3.3 IEEE802.16c‐2002...... 38 3.3.4 IEEE802.16d‐2004 ...... 38 3.3.5 IEEE 802.16e‐2005 ...... 39 3.4 Some Significant Features of WiMAX ...... 40 3.4.1 OFDM Based Physical Layer ...... 40 3.4.2 Adaptive Modulation and Coding (AMC)...... 40 3.4.3 TDD and FDD Support ...... 40

viii

3.4.4 per User Resource Allocation...... 40 3.4.5 Quality of Service (QoS) ...... 40 3.4.6 Advance Antenna Techniques Adaptation...... 40 3.4.7 Link layer Retransmission ...... 41 3.4.8 Mobility...... 41 3.4.9 Scalability ...... 41 3.4.10 High Data Rate ...... 41 3.4.11 Security ...... 41 3.4.12 IP based Architecture...... 41 3.5 Technological Aspects of WiMAX ...... 42 3.5.1 Fixed WiMAX...... 43 3.5.1.1 PHY Layer ...... 43 3.5.1.2 MAC LAYER...... 44 3.5.2 Mobile WiMAX...... 44 3.5.2.1 PHY Layer ...... 44 3.3.2.2 MAC Layer...... 45 3.6 Architecture of Mobile WiMAX...... 46 3.7 Mobility in WiMAX...... 49 3.8 Handovers in WiMAX ...... 49 3.8.1. Hard Handover (HHO)...... 50 3.8.2. Fast Base Station Switching (FBSS) ...... 50 3.8.3. Macro Diversity Handover (MDHO)...... 51 3.9 WiMAX System Components ...... 52 3.9.1. WiMAX Base Station (BS)...... 52 3.9.2. WiMAX Receiver or Customer Premise Equipment (CPE) ...... 52 3.9.3. BACKHAUL...... 52 3.10 WiMAX Working...... 53 3.10.1 Advanced Working Features for WiMAX ...... 54 Chapter 4 ...... 56

COMPARATIVE ANALYSIS...... 56

ix

4.1 Comparison of Physical Layer Access Techniques ...... 56 4.1.1. OFDMA for WiMAX ...... 57 4.1.2. WCDMA...... 58 4.1.2.1. Frequency Division Multiple Access. (FDMA) ...... 59 4.1.2.2. Time Division Multiple Access (TDMA) ...... 59 4.1.2.3. Code Division Multiple Access (CDMA)...... 60 4.1.2.4. Description...... 60 4.1.3. Comparison (WCDMA and OFDMA) ...... 63 4.2 Comparison of Modulation Schemes...... 65 4.2.1Binary Phase Shift Keying (BPSK): ...... 66 4.2.2. Quadrature‐Phase Shift Keying (QPSK)...... 68 4.2.3. Quadrature Amplitude Modulation (QAM) ...... 68 4.3 Comparison of Handovers ...... 70 4.4 Comparison of Channel Impairment and Equalization...... 70 4.5 Comparison of Architecture...... 71 4.6 Capacity and Coverage Comparison ...... 75 4.6.1 for WCDMA ...... 75 4.6.1.1. Coverage and Cell Range in WCDMA...... 76 4.6.2 FOR WiMAX...... 77 4.6.3. Capacity Estimation for WiMAX and WCDMA ...... 79 4.7 Spectral Efficiency...... 81 Chapter 5 ...... 83

SIMULATIONS...... 83

5.1 Simulations Using AWGN Channel Model ...... 83 5.2 BPSK ...... 84 5.3 QPSK...... 85 5.4 16‐QAM...... 86 5.5 64‐QAM...... 88 5.6 Simulations using Rayleigh Fading Channel Model...... 90 Chapter 6 ...... 95

x

CONCLUSIONS...... 95

6.1 Conclusions ...... 95 6.2 Future Work...... 96 REFRENCES...... 97

APPENDIX A...... 102

Abbreviations and Acronyms...... 102

APPENDIX B...... 109

Matlab Simulation code...... 109

xi

LIST OF FIGURES

Figure2. 1 Standardization and commercial operation schedule for WCDMA and its evolution [4]………..8

Figure2. 2 Peak data rate evolution for WCDMA [4]…………………………………………………………………………………… 9

Figure2. 3 System evolutions [4]…………………………………………………………………………....9

Figure2. 4 Direct Spread…………………………………………………………………………...... 11

Figure2. 5 General UMTS Architecture [2]……………………………………………………………….13

Figure 2. 6 UTRAN Architecture [2]…………………………………………………………………..…15

Figure2. 7 Architecture of Umts Core Network (Release 99) [2]…………………………………………17

Figure2. 8 UMTS Architecture Release 99[9]…………………………………………………………….19

Figure2. 9 UMTS Protocol Layer [2, 70]…………………………………………………….…..20

Figure2. 10 UMTS Channel Mapping [13]…………………………………………………………..……23

Figure2. 11 Spreading and Scrambling [4]……………………………………………………………….25

Figure2. 12 UMTS cell structure [2] [14]…………………………………………………………………26

Figure2. 13 Power Control to Resolve Near Far Field Effect [8]………………………………………....28

Figure2. 14 Inner and outer Loop Power Control [2]……………………………………………………...29

Figure2. 15 UMTS MAC Layer [10]……………………………………………………………………...30

Figure2. 16 Radio Link Control Layers [10]………………………………………………………………31

Figure2. 17 Hard Handover [20]…………………………………………………………………………..33

Figure2. 18 Soft handover [20]……………………………………………………………………………34

Figure2. 19 Softer Handover [20]………………………………………………………………….34

xii

Figure 3.1 WiMAX Standard [23]...... 39

Figure 3.2 Representing WiMAX as subset of IEEE802.16 [31] ...... 42

Figure 3.3 MAC layer of WiMAX [28] ...... 44

Figure 3.4 Mobile WIMAX Reference Model [23]...... 47

Figure 3.5 WiMAX network architecture [28]...... 49

Figure 3.6 Fast Base Station Switching [43]...... 50

Figure 3.7 Macro Diversity Handover [43] ...... 51

Figure 3.8 Backhaul (WiMAX) [45]...... 53

Figure 3.9 WIMAX working [23] ...... 54

Figure 4.1FDMA [50] ...... 59

Figure 4.2 TDMA [50] ...... 59

Figure 4.3 CDMA [50]...... 60

Figure 4.4 WCDMA Frequency band ...... 61

Figure 4.5 Spreading and Despreading [9]...... 62

Figure 4.6 Block Scheme of WiMAX Signal Transmission from OFDM Based TX to Rx [53]...... 65

Figure 4.7 QPSK constellation...... 68

Figure 4.8 constellation 16QAM, 64 QAM...... 69

Figure 4.9 WIMAX Architecture [57]...... 72

Figure 4.10 UMTS Integration...... 73

Figure 4.11 Network Architecture for UMTS and Mobile WiMAX [57]...... 74

Figure 4.12 UMTS Cell Structure [61]...... 76

Figure 4.13 Data Rate of Impact Modulation in WIMAX Network [62]...... 78

Figure 5.1 Simulations Model with AWGN Channel ...... 83

Figure 5.2 ...... 85

Figure 5.3 ...... 86

xiii

Figure 5.4 ...... 87

Figure 5.5 ...... 88

Figure 5.6 ...... 89

Figure 5.7 ...... 89

Figure 5.8 Reflection, Diffraction and Scattering...... 91

Figure 5.9 Refraction...... 91

Figure 5.10 Multipath Propagation of radio waves...... 92

Figure 5.11 Simulation Model with Rayleigh Fading Channel…………………………..……………….93

Figure 5.12……………………………………………………………………………………………………………………………………………93

Figure 5.13……………………………………………………………………………………………………………………………………………94

xiv

LIST OF TABLES

Table 1.1: Cellular Network Generations [1] ...... 5

Table 2.2 UMTS Services ...... 35

Table 3.1 Comparing Physical Layer in Mobile and Fixed WiMAX [39]...... 45

Table 4.1 Technology Comparison [46]...... 56

Table 4.2 Different Parameters in WiMAX [51]...... 58

Table 4.3 Comparison of WCDMA and OFDM [71]...... 65

Table 4.4 Main Parameters OF UMTS and WIMAX IEEE 802.16e [53] ...... 560

Table 4.5 UMTS cell coverage comparison ...... 77

Table 4.6 WiMAX Different Coverage Range [62] ...... 80

Table 4.7 Spectral Efficiency Comparison [69]...... 83

xv

Chapter1 INTRODUCTION

elecommunication world has undergone tremendous changes during the past ten years. Both technical and political factors have contributed towards the evolution of telecommunication systems,T especially in the development of mobile broadband. In the world of telecommunications, most of the telephone and radio networks involved are wireless in nature. Also various television networks and internet are used to be wireless in nature. Cellular networks are also use to be wireless, with an improved level of Quality of Service (QoS) and better mobility. While studying the advancement in the field of mobile communications and cellular networks, we come across various generations, which were introduced successively.

In the first generation (1G), portable devices of large sizes employing analog communication systems were introduced. Advance Mobile Phone System (AMPS) was introduced in 1976 in USA. Total Access Communication System (TACS) was adopted by Europe, England, Hong-Kong and Japan using 900MHz frequency band and Extended Access Communication System (ETACS) which is an enhanced form of TACS which uses greater number of communication system subscribers and was adopted in United Kingdom, are the example of 1G standard.

In second generation (2G), a shift from analog to digital communication systems took place and cellular networks also adopted digital communication systems. In mobile telephony, the major 2G standards are Global System for Mobile communication (GSM) with 900MHz and 1800 MHz frequency bands in Europe and United States. Code Division Multiple Access (CDMA) in which signals are spreaded over a large range of frequencies employing a spread spectrum technique and Time Division Multiple Access (TDMA) was adopted in America and New Zealand. TDMA involves time division for the channels resulting in higher transmission data rate.

The 3rd generation of mobile communication can rightly be termed as the generation enabling mobile broadband i.e. it has attained the capability of wireless use of internet or work over an IP network. Mobile broadband has now been remarkably adopted world wide and attempts are being made to achieve even faster data rates up to several 100 Mbps. Two different standards have been embraced by the industry to attain such high speeds and move into the next generation and those standards are UMTS employing Wideband Code Division Multiple Access (W-CDMA) and World Interoperability for Microwave Access (WiMAX) employing Orthogonal Frequency Division Multiple Access (OFDMA).In third generation (3G), Universal Mobile Telecommunication System very highqualityofvideostreaming andconferen WiMAX deliverssome outstandingf of ETSI. converge anddevelopaninter-workingbetween range offiftykilometers andhypotheticaldatara standard andEuropeanTelecommunication Standa (WiMAX) referstoacompatible system of WiMAX.including physicallayerofUMTSand Our researchisaimed atthecomparison ofstanda rate andaverylarge variet rangeofpacketdata (WCDMA) forawidefrequency very highthroughput and datarates. UMTSem (UMTS) wasintroducedandadoptedinEuropea y oftrafficonairinterface. eatures includingsupportforall equipment beingdevisedforAmerican IEEE802.16 IEEE802.16standardandtheHiperMAN ployed Wideband CodeDivisionMultiple Access cing andalsohighqualityvoiceoverIP(VoIP). Worldwide Interoperability forMicrowaveAccess nd some otherpartsof theworld.UMTSenabled rd Institute(ETSI)HiperMANstandard.Ithasa te of100Mbps.Theeffo rds, services,architectureandvariousfeatures services for users. UMTS offered variablebit servicesforusers.UMTSoffered 2G and3Gnetworks,offering rts arebeingmade to

1G NETWORKS 2.75G networks 2.5G networks Specification 2 Gnetworks

CDMA 2000 1xRTT 2000 CDMA Data TAC EGPRS 2 Protocol Mobitex WiDEN HSCSD CDMA TDMA FDMA AMPS EDGE TACS GPRS iDEN NMT GSM PCS

1.2 Mbps(down link 473kbps(uplink) 473kbps(uplink) Up to kbps to 114 Up Up to to 144Kbps Up Up to to 100kbps Up to 384kbps Up Up to 20Kbps Up to to 64kbps Up Speed N/A

Voice serviceonly(analog) including support for short • Real-time location-based Better performance for all Simple data application application Simple data audio and video clips, All 2G features plus: Digital voice service service voice Digital • MMS (Multimedia • MMS(Multimedia such email andweb Conference calling Push-to-talk(PTT) Push-to-talk(PTT) games andimages Basic multimedia, multimedia, Basic such as directions Message Service) • Web browsing browsing • Web No data No data service 2/2.5G services Short massage service(SMS) Voice mailVoice Caller ID Features browsing services

3.5G networks 4G Networks 3G networks

CDMA 2000 EVDO ( ( EVDO 2000 CDMA CDMA 2000/EVDO 2000/EVDO CDMA CDMA 2000EVDO 2000EVDO CDMA UMTS/WCDMA Voice and data) EVDO Rev B CDMA 2000 2000 CDMA WiMAX HSDPA Rev A Rev UMB LTE

Up to 14.4 Mbps 14.4 to Up Up to 3.1 Mbps Up to 2.4 Mbps Up to 2.4 Mbps Up to 46 Mbps Up to 2 Mbps

Support for all prior 2G/3G • High quality streaming streaming • High quality Support for all 2/2.5/3G • Faster browsing • Faster Web • Faster Web browsing browsing • Faster Web Support for all 2G and • Video conferencing (especially graphics • On-demand video • Full motion video 2.5G features plus: • Streaming music intensive sites) intensive features plus: features plus: • 3D gaming video

1.1.4 Chapter5 coverage, capacity,mobility andhandovers, demerits ofbothtechnologies of boththetechnologieswiththeirradioaccess t In thischapter,thetwotechnologi 1.1.3 Chapter4 physical layerincludingmodulationtechni management, its multiple techniques OrthogonalFr the aspects related to WiMAX networkarchit enables avarietyoftraffictobe feature ofWiMAX increases its Physical layerofWiMAX includes orthogonal 802.16e standards.TheairinterfaceforWiMAX is standard isclassifiedfurtherintotwofo description ofitsarchitecture.TheIEEEst This chapterinvolvesallthet 1.1.2 Chapter3 physical aspectscomprehensively. technique, aretakenintospecial depth. Alsospecificationandfeat MAC layerdescription, handoverstrategies andothe description ofarchitecturew In thischapter,background,development history,st 1.1.1 Chapter2 1.1 ThesisLayoutandShortDescriptionofChapters Table ith emphasis on Radio Access Netw ith emphasisonRadioAccess consideration.UMTS/WCDMA isdi accommodated i.e.voice,videomultimedia .thischaptercoversall echnical specifications andfeat effectiveness andelegance. Theflexibility ofWiMAX MAClayer are discussed whilemutually comparing thosewithrespect to

es i.e.UMTSandWiMAX arecompar 1.1: ure of WCDMA, whichisemployeure ofWCDMA,

Cellular NetworkGenerations r fixed WiMAX WiMAXr fixed with802.16dandmobile with ques (adaptive)andotherfeatures. equipment andarchitecture complexity. andard forWiMAX ThisWiMAX isIEEE802.16. echniques arediscussedandcompared. Merits and frequency division multiplexing (OFDM).This andards, capacityandcoverageaspects,detailed equency DivisionMultiplexing (OFDM)based r multiple features of UMTS areexplainedin ecture, Qualityof service(QoS),mobility considered tobevery ures ofWiMAX alongwiththe

[1] ork (RAN),Physicallayerand scussed intechnicalaswell d inUMTSasaradioaccess

ed indetail.Physicallayers robustandflexible.

interworking architectureforboth This chapter includes the final interpretation of 1.1.5 Chapter6 adopted theresultsarecompared anddiscussed 16QAM and64QAM.Twosimulation models i.e. Simulation isdoneinMATLABformodulation tec the technologiesiss with respecttosignal thecomparison oftheUMTSandWiMAX andan AWGN and RayleighFadingChannelmodelsAWGN and are hniques ofbothtechnologi uggested tobeworkedoutasfuturework. power anderrorrates. es i.e.BPSK,QPSK,

throughout theworldand geographically based onGSMstandards. Duetoitswellorganized UMTS offersareliableservice formobileusersre data ratesupto2Mbps[2]. transmission. a3Gtechnologyknownas UMTSis systems whicharebeingdevelopedinto4G.Pre ITU, alsofulfills the requirements of 3GSystems. general nameisInternationalMobileTeleco being developedundertheInternat Telecommunications System (UMTS)hasbeen launche developed basedonGSMnetworks. exists insome regionsofth different regionsduetowhich2G advance mobility, voiceoriented wirelesscommuni (2G).Second generationofmobile Mobile communications (GSM)waslaunchedwo systems globally.HenceGroupSpecialMobile(GSM correspondingly increasing service demands initiate American MobilePhone System Theincrea (AMPS). the analogtransmission. in 1Gwasestablished I 2.1 Introduction TELECOMMUNICATIONS First generationofmobile co n mobile communication,thethreedifferentgenera UNIVERSAL e world.3G,thethirdgenerationof mmunication systems wasdeployed ional TelecommunicationUnion-Te communication isbasedondig couldnotbesuccessfullydepl Third generation(3G)whichis Chapter (UMTS) mobile usersarecapableto mmunication-2000(IMT-2000) siding inanyplaceoftheworld.UMTSismainly NordicMobileTelephone(NMT)systemand sently UMTS system uses WCDMA for radio sently UMTSsystemusesWCDMAfor cation system. Thereweredifferentstandards in

UMTSisoneof th d thedevelopment ofdifferentcommunication 2 tions havebeenemerged throughouttheworld. standards formobile users,UMTS nowexists rldwide whichiscalledSecondGeneration next waveofmobile broadbandwhichoffers

sing number ofusers

d inmostregionsofth ) whichlaternamed asGlobalSystemfor MOBILE

oyed alloverthe recognized asUniversalMobile continuously acce mobilecommunications was ital networkswhichprovided in early1990swhichincluded lecom Sector(ITU-TS)whose

e 3Gmobile broadband SYSTEM which isasubgroupof of mobile systems and e world.UMTSisalso

world.2G still ss theinternet

under consideration.Nowaday3GPPisalso has beentakeninhandcommercia was usedduring2007.FurtherHSPAEvolution m commercially itwasusedduring2003.HSDPA wa started workduring2001inJapan.InEurope Third generationdevelopedane [4] standardization setendedin1999whichiscalledRelease99. comprehensive standardization work hasbeenacco standardize bodydecidedin1998thatWCDMAwill performance andbasicunderstandingof projects CODITandFRAMSin1990s.Intialythis Telecommunication (UMTS).Theresearch work Evolution isthemost generalterms whichis 2.3 EvolutionofUMTS/WCDMA telephony 2000(IMT2000)[3]. Telecommunication StandardizationSector(ITU-T) in thosenumberofstandardswhichhavebeen collaboration withJapanesestandardization Third generationstandardpresentedbyEur 2.2 WhyUMTS through terrestrialandsa service with roaming facility Commercially Commercially

3GPP Figure2.

R99

20

Standardization andcommercial operati

2000 3GPP R99 3GPP

R5 2001

tellite transmission.

3GPP R5 3GPPR63GPPR7RGPPR8 2002 when theyaretraveling.Users arecapable toaccessUMTSsystem 3GPPR6 w radio access method which was w radioaccessmethod which lly. Currently HSPA Evolution wh lly. CurrentlyHSPAEvolution 2003

3GPP Schedule 3GPP Schedule working overLongTerm Evolution(LTE). group whichproposedUMTS 3GPP approved byInternationalTelecommunication Union- 4 200 WCDMA standardization ETSI , A European WCDMA standardization ETSI ,AEuropean usedinthebackgroundofUniversalMobile it started work in a testing phase in 2002 but itstartedworkinatestingphase2002but opean MobileTelecommunication systemin

oved to3GPP(Release7)andnowitsdeployment R7 onWCDMA startedbyEuropeanresearch mplished asmain partof3GPP.Firstcompleted s commerciallylaunchedin2005andHSUPA undertheprotectionofinternationalmobile on scheduleforWCDMAanditsevolution 2005 project wasdevelopedto be thethirdgeneration airinterface[4].A R8 2006 WCDMA andcommercially it ich isrecognize 2007 .UMTS isalsoincluded 2008 evaluatethelink 2009 d asHSPA+is 2010

seeking todeployHSPAorWiM (EVDO) iscommerciallylaunchednowaday.Toim fortheiropenecosystemGSM/WCDMA andlowco to getanumber of benefits currently more (LTE).The market sharehasbeen declinedsi WCDMA. OnthesamepathGSMandWCDMA are networks havealreadybeenesta seamless handoversanddualmode handset. Mos 80 to90%globalmobile subscr Global System forMobilecommunication (GSM)a 2.3.1 SystemEvolution Downlinkpeakrate 3GPPR99R5R6R7R8 3GPPSchedule

CDMA GSM

0.4Mbps 0.4Mbps

Figure2. EVDO

Figure2.

21

EDGE 14.0Mbps 0.4Mpbs

Peak datarateevol AX andLTEinthelongrun[4]. WCDMA blished .However,GSMandEDGE iption. WCDMA iscompatible withothersystems likeGSMin

22

System evolutions [4]

5.7Mbps 14Mbps nce 2004 when CDMA 2000 moved CDMA2000 toGSM/WCDMA nce 2004when HSPA then 10%.Maximum operatorsofCDMAmoved to EDGE tly WCDMA networksaredeployed whereGSM ution forWCDMA[4] 11Mbps 28Mbps

nd WCDMA hasajointacc evolution

evolution prove dataratesfurther some operatorsare also compatible withLongTerm Evolution LTE st mobiledevices.EvolutionDataOnly

HSPA 42 16OMbps LTE 50 mBPS

Mbps

LTE

are deployedinparallelwith

Uplink peakdata ount wheretheyhave

currently deployedinUM Wideband CodeDivision Multiple 2.4 WCDMA

Channel coding Convolution and Turbo codes Convolutionand Data indownlink multiplexing Channel detection Coherent 3.84 Mbps Channel coding Data modulation Spreading modulation length Frame Chip rate structure channel RF Downlink Duplex mode Channel bandwidth Power control Open andfast Open multimode and Variablespreading Handover Spreading (downlink) control Power Spreading factors MultiMate inuplink multiplexing Channel

Table TS mobile networks.

2.1:

Parameters ofWCDMA[6] Access(WCDMA) isaradio QPSK (Downlink) (Downlink) QPSK 10 ms spread Direct 4-256 (uplink) and4-512(uplink) forda multiplexing I&Q multiplexed channel time Control andpilot the downlink pilot in common uplink), and (downlink pilot multiplexed time User dedicated BPSK (Uplink) Complex spreading circuit Complex spreading (Uplink) Dual-channel QPSK (Downlink) Balanced QPSK TDD FDD and 5MHz Soft hand over inter-frequency handover handover overinter-frequency Softhand ms) 10 cycle (truncated user separation forcelland 218-1 Gold sequences for channelseparation sequences OVSF and control channels time multiplexed multiplexed channels time and control closed loop (1.6 kHz)closed loop(1.6

ccess technology whichhasbeen ta and control channel control ta and

• • Directspread(DS) TheWCDMA standardwasdevelopedfor • The keycharacteristicsof WCDMAaredescribed below. 2.4.1 SomeSignificantch TDD isusedforunpairedband[7]. Duplex FDD)andthesecondisTime Division types ofduplexmethods areusedinWCDMA/UM transmitted bitsby theusersarespread through Underlying techniquelikedirect of service(QoS)toachievethetarget of designWCDMAairinterfacewa fulfills the need ofhighdatarateand multiuser acce ETSI alphagroupdesignedthis

Synchronization ofNetwork Synchronization 3.84Mcps wasselectedaschipratefor WC Nominal bandwidth capable toworkinsynchronoustiming [8]. synchronize basestationtiming withsatellitebase In WCDMA environmentbasestationperformth 5MHZ WCDMA WCDMA

aracteristics ofWCDMA

sequencespreadspectrum(D radio accesstechniquewhich Figure2. ofhighdataratesupto2Mbps.[5] Direct s developedtosupportseveralserv (3.84Mcps Chip Rate

23

Spread

Direct Spread 5MHz asanoperationchannelbandwidth[8]. DMA, Which islargerthanCDMA2000. a widerbandwidth than therealinformation. Two Duplex (TDD).FDDisusedforpairedbandand )

ss tothe networkat thesame time .Theconcept TS networks.FirstoneisfrequencyDivision timing. Howeverthesebasestationsarealso eir taskasynchronously.Thereisnoneedto was completedin1999.WCDMA SSS) is used in WCDMA where SSS) isusedinWCDMAwhere ices withdifferentQuality

interface [2]. and corenetwork.Thefunctionofreferencepoint is aninterfacebetweenCSand connected through IUinterface.Th of CoreNetwork(CN)isswitchingandrout transceiver andantenna.It The main ofUniversalTerrestrialRadio part both domains isdescribedasbelow. physical bodies.Thereferencepointsareassigne (UE) andinfrastructuredomain. The generalarchitectureofUMTS UMTS, amajorchange suchasInternet Protoc without bringinganychangeintothecorenetwork. [3].UMTS introducedanewradio introduced asadrivingtechnol support alltypesofservices The development in3Gnetworksisbasedonth 2.5 ArchitectureofUMTSNetwork • •

• InUserEquipment domain • capable of performing severalparallel tasksinthe same link[8]. WCDMA providessupportforavarietyofservices High DegreeofServices favor ofGSMnetwork[8]. WCDMA iscapableofinterfacing withGSM-MA Core Network

terminate the radiointerfaceinordertopr In UMTS,infrastructuredomain includesphysic Infrastructure domain principle User Equipment domain(UE) establishesalinkbetween basestationandmobile station. The main role suchlikedata,videoandvoiceconve RNC andsecondlyIU-CSi.e.an Each planneddomain characterizes ogy. GPRSpresentedIP backboneintomobile corenetwork access technologywhichistotally users acquiretheservicesofUMTS. ere aretwomaininterfaces as physically consistsof ing innetwork.CorenetworkandUTRANare Access Network (UTRAN) consists ofcontroller, Access Network(UTRAN)consists ol (IP)isintroduced ovide endtoservice theuser. e evolutionofGSM/GPRS Uu whichseparatesbothdomains called asradio d betweeneachdomain. Furtherthefunctionof After implementation ofsuccessivereleases P corenetwork.Basically twomain domains i.e.UserEquipment likeupto2Mbpsdataratesandalso al nodeswhichareresponsibleto interface betweencircuitdomain shown, firstoneisIU-PS,which in corenetwork[2]. rsations. InternetProtocol(IP) is amaximum levelgroupof basedonradioaccessnetwork networks.3Gnetworks itwasdevelopedin

part i.e.Accessnetwork (UTR end serviceforUserEquipment. This partcontains physicalbody wh 2.5.4 InfrastructureDomain protected way whereencryption and authenticati It isaremovable smart cardwhichis 2.5.3 UMTSSubscriberIdentityModule (USIM) application. Bothentitiesarephys mobile terminal istomaintain radio transmission divided furtherintwopartsi.e.mobile terminal User Equipment comprising aphysical structure likea 2.5.2 MobileEquipment(ME) general architectureitdivide EU isreferredtoastheterminal whereusersuse 2.5.1 UserEquipmentDomain Uu

User Subscriber Module Identity (USIM) UMTS

Equipment CU

(UE)

Domain Equipment Mobile (ME)

d furtherintwoparts.

AN) and CoreNetwork(CN) AN) and Figure2.

ically situatedinsame card. Functionally, Infrastructure domain isfurther categorised intwo ich isusedtoterminate thera assigntoeachuserwhich allows

24

General UMTSArchitecture[2] [ Infrastructure

Network (AN) (AN) Network domain Access on processinanycaseofMEi.e.used[2

all services withhelpof radiointerface. InUMTS, (TM) and terminal equipment. Themain role of and thatof terminal Equipment istocontrol the

domain handset istermed asmobile equipment. Itis Lu

Core

[Zu] Network (HN) Network domain domain (SN) Network Serving dio interfacewhich providesend to domain domain

Home

Network theusageofallservicesina

(CN) [Yu]

domain

Network

domain

Transit ].

(TN)

Two operationmodes have beenregulated forUTRN Radio interface. 2.6.1 OperationMode ofUTRAN logical functionsasbelow. interface and networkandfurtherone ormore sect node BorbasestationsareconnectedwithIub Node Borbasestationsarepresent.RNC arec of radionetworksubsystems. Thereisonlyone develop connection isalso calle through Uuwhich In aUMTScelleveryRNSisresponsibletor connected to corenetworkwithIU terminal and core network. Inthefigure (2.5) itis transmission betweenuserEquipm The main function of UTRANistomake andmaintain aRadio Access Bears (RABs) for reliable 2.6 UniversalTerrestrialRadioAccessNetwork(UTRAN) 2.5.4.3 TransitNetwork (TN) Actually SN isresponsible totransfer 2.5.4.2 ServiceNetwork (SN) are requiredtobeincoordinationwi The serviceprofilesofuseralong 2.5.4.1 HomeNetwork (HN) The threedifferentsubdomains aredescribedbelow. where userscommunicatewith Regarding corenetworktherearethreedifferents transmission path. It establishes alinkbetween SNandremote party • • •

Drift RNC...... itperform handoverwithrespecttoUE insoft Serving RNC(SRNC)...... itf Controlling RNC(CRNC)...... itworkregarding nodeB

eachotherindifferenttypesofne with parameters forsecureidentification arecontained inHNand interfacewhichisareferencepoi ent andcorenetwork.Itestablis th theparametersofUSIMatUE. user’s datafrom sourcetodestination. unction occurringwithUE onnected witheachother throughlurinterfacewhile .Node AandNodesBarebr eceive anddelivertheinformation .UEandRNS radionetworkcontrolle stated that Radio Netw d radiointerface. UTRANalsocontainanumber ub domainscharacterisedin ors aregenerated[2][9].RNCperforms several

because thiscorenetwor twork likefixedormobilenetwork. hes aconnectionbetweenmobile nt inUMTSarchitecture model.

r (RNC)andanumber of ork Subsystem (RNSs) is ork Subsystem (RNSs) eak pointsbetweenair differentsituations k isplacedin

2.6.1.2 UTRANTDD(Time Lu 2.6.1.1 UTRANFDD(Frequenc • • • •

They areabletouseunpaired band. downlink transmission. usedatthesameTDMA andCDMAare These arecapabletousepairband. network. WCDMA isusedasaccesstechnique durin

NODE NODE NODE

NODE

division Duplex) B B Figure2.

B

y DivisionDuplex) B

Iub

Iub 25 Iub

UTRAN Architecture[2]

Iub

Lur ‐ g

Iur GERAN as anaccesstechnique duringuplink and g uplinkanddownlinktransmission ina

RNC RNC

UTRAN RNS

BSS

RNS Lu lu

Iur Lu ‐ g

CN

isgiven in acorenetworkofUMTS desc [2].Abrief HLR, MSC isachievedbycombiningmanagement CSand involved in thesession management andmobili both perform theirdutiesas PS domain dependsonservingGPRS nodes(SGS 2.7.2 PSDomain (MSC) andGatewayMSC,home locationcentre the corenetworkperforms various switchingf The servicesperformed byCSare In UMTSnetworktheroleofCSdomain is 2.7.1 CSDomain [2]. aspect traffic There aretwomain domains inUMTScorenetwor towards theIPbasednetwork[2][10]. in corenetworkofarchitecture,after which main examples of itsfunctionalities. Innewrele access technologies. Connection management, sessionmanagement andmobility management are network. As aresult thereis achance tomerge di infrastructure domain whereitco transfers one user’sinformation toitsrelevant stage inthecommunicationnetwork.Corenetwork Core networkofUMTSprovide 2.7 CoreNetwork • •

To manage thenetworkcharacteristic. maintainTo theuserlocationinformation. ription ofcorenetworkelements here a routerandgateway(onlinebook vers allaspectswhic s allservicestoits to providesupportfortrafficcontrol. ases ofUMTS,some changeswere main introduced the Radioaccesspartbecame stableandmoved unctions forCSthroughMobileswitchingcanter PS throughcollaborationofSGSN,GGSN.VLR, (HLC),visitor location fferent networkarchitectur destination .Corenetwork N) andgatewayGPRS supportnode(GGSN), is recognizedasalongrangnetworkwhich ty management. Insome cases,mobility k andtheyarecategorizedregardingtouser subscribers thus it is known as fundamental subscribers thusitisknownasfundamental h don’thaveadirect abriefdescription oftheelements performance). Theyarealso register(VLR). es withdifferentradio is the main part of link to radio access link toradioaccess

UTRAN

RNS Iu_PS Iu_CS

Iu_CS

Gs

E MSC

SGSN MSC

Figure2.

GF

F

E E

I I R R

26 B

Architecture ofUMTSCoreNetwork(Release99) [2] B

Gr G

VLR VLR

PS

domain

D Gn/GP

NC

NC

CS

AuC CORE

domain

NETWORK H

Gc GMSC GGSN HLR

C

and alsoresponsibleforallincoming / Basically itisa particular MSCthat offers CSse 2.7.8. Gateway MSc(GMSC) compared thereafter[11]. from random numbersof128bits alongwiththe networks forcommunication. A3algorithm isempl Authentication procedureisbasicallysettoopera 2.7.7. AuthenticationCenter(AuC) [2]. call Meanwhile ifMSisnotableto register, theVL the MSC,sendsanoticeforregistryandthentran any interaction withHLR.If mobile usersenter in location information regardingtheusers.Onmany VLR isresponsibletomanagetheroaming ofMS 2.7.6. VisitorLocationRegister(VLR): the service profiles. Itscoreresponsibili The information ofthesubscribers 2.7.5. HomeLocationRegister(HLR) (USIM). It isreferredtoasuserequipment whichhasm 2.7.4. MobileStation(MS) procedures. capacity ofmanaging handoversandothermobility provided orhandledbytheMSC. UMTS. IuCSinterface th isusedbytheMSCfor MSC canactuallybedefined asacentralsign 2.7.3. MobileSwitching Centre(MSC): Theadditional feature of MSCinUMTSisitscapability and is containedbytheHLRforapart out goingcallstotheexternalnetwork. ty isthemanagement ofmobile users. R andHLRsharetheir information to acceptthe new obile equipment andidentification cardfor UMTS aling andswitchingfunc rvices betweencorenetw anynewregionofMSCthentheareawhichcover withintheboundaryofMSC.VLRhasparticular te onchallengeandres occasions itaccomplishes sp sfer toVLR,wheream e interaction withRAN. Also,CSservices are oyed forthecalculation related functionalities authentication keyKi. icular network.Italsoincludes ponse principleinUMTS ork andexternalnetwork tions perfor like positionregistering obile stationisplaced. Values ofSRESare of SRESparameters ecific taskswithout ming unitin

the fundamental characteristics Because thisisaquitedeferent technology ascomp WCDMA hasbeenacknowledged a 2.8 Description of UMTSRadioInterface session, mobility andaccounting/billingmanagement. interface .Itworksinpacket domain same asGMSC A communication isestablishedbetweenUMTS 2.7.10. Gateway GPRSSupportNode three main functions which are security ta It worksinpacketdomain similar toVLRandMSC 2.7.9. ServingGPRSSupportNode UE

Figure2.

27 of UMTSradiointerface network.

UMTS ArchitectureRelease99[9] UMTS nd adoptedasanai sk, access controland mobility management. are toGSM/TDMA.Itis veryessentialtoknow network andexternalthroughGGSN worksinCSdomain .GGSNalsomaintains the working inCSdomain. SGSNisresponsiblefor r interfacetechnology for UMTSnetworks. networks switched packet To other PLMN, ISDN networks To other

Broad CastControlChannel (BCCH) Control logical channel transmits informa 2.8.1.1 Controllogicalchannels channels. [2].Logical channelarefurtherdivi control information transfer, these channelsar transfer oftheinformation between theMAClaye Depending upontheinformation whichisbeing 2.8.1 Logicalchannels farther facilitateavariab By means ofthisdivision ofchannels,the radi categorized asLogicalchannels,Trans UMTS architecture provides threetypes ofchannels •

Defined indownlinkdirection only

Ph y Trans Logical sical le Qualityofservice.

Channel

Channel Figure2. ded intotwoparts,controllogi p port channels,andPhysicalchannels ort tion regardingchannel

28 Channels

UMTS ProtocolLayer[2,70] s o interfaceadoptsdifferent e usedtobemapped ove inaccordance withthe pr communicated, logicalchannelscarryoutthe r andRLC layerforusertraffictransferand s control [2] [12] control [2] cal channelsand trafficlogical configurations which otocol layerwhichare r transport channels

the wayoftransfer of inform Transport channelsaredefined betweenMACandphys 2.8.2. TransportChannels Common TrafficChannel(CTCH) Dedicated TrafficChannel(DTCH) Logical trafficchannelsarere 2.8.1.2 Trafficlogicalchannels ControlChannel(SHCCH) Shared Channel Dedicated ControlChannel(DCCH) Common ControlChannel(CCCH) Channel(PCCH) Paging Control • • • • • • • • • • • • •

It isaunidirectional poi It transfersspecificuserinformati Itisbidirectionalwithre It isdefinedinuserplane. Carries initialization massage transmitted byUE. Responsible fortransferringdata ItisaPointtopoint Transports signalinginformation. It isapointto It isalsodefinedindownlink. Used fornotificationofincoming message. Containscarriercontrolinformation Contains cellspecificinformation bidirectional channel. bi directionalchannel. sponsible todelivertheinform nt topointchannel. spect touser’straffic. ation toradio interfacefrom logicalchannel. Format ofthedata regardingdedicatedcontrol. on tomore thanoneuserandgroup. ical layer.Theirmain functionisto specify ation regardinguseraspect

Downlink SharedChannel(DSCH) Uplink CommonPacketChannel(CPCH) Channel(RACH) Random Access (PCH) Paging Channel Forward AccessChannel(FACH) Broadcast Channel(BCH) Dedicated TransportChannel(DDC) system configuration.Thesechanne logical channel.Logicalchannelsarebeingmappe transmission regardingbiterror • • • • • • • • • • • • • channel [2]. channel There anumber ofuserscanparticipate at th It isdefineddownlinkonly. It isusedinsupportoffastpowercontrolling. It isdefinedinuplinkdirectiononly. access thenetwork [12]. This channelprovides It isdefinedforuplinkonly. It canreceiveinformation Carries information regardi It isspecifiedfordownlink Supposed todeliverthedata. Defined indownlinkdirectionon intended toreceiveinformation fromUE. A broadcastchannelwhich hasinformation a It isdefinedasbidirectionaldedicated support tocarrytherequ rate, codingofthechannelandin by anyEUthroughoutthecell. ng incoming call,datasession. ls aredefinedas[12][2]. ly andalsospecificforUE. channelspecificforuserEquipment d ontothetransportchannelsaccording e same time toaccess the information inthis est ofuserEquipment bout userequipment w terleaving isdefinedbytransport which isintendedto ithin cellandalso

Figure2.

29

UMTS ChannelMapping[13]

due tofollowingmerits ofthetechnique[4]. widely adoptedschemes forspreadingadatasignal on theconceptoffrequencyreus All spreadspectrum techniquesareknownfortheeffi transmitter power. to each userwhichalsofacilitates users aredistinguished from eachother onthebasis of signals.The same bandisutilizedby frequency average powerspectraldensity.Simplyviewing,th The levelof interference isreduced inthesespr spectrum systems utilize agreater bandwidth as compared tothenormal for thedata transmission. All CDMAsystems referredtoasspread are 2.9.1 SpreadSpectrum information signalandalsothiscode isagainreus actual signalbandwidth.Thisspectra type ofmodulation system wherespreadspectrum important characteristicfeatures are alsoexecutedinthephysical number ofotherfunctionalities transport channels tophysical ch It hastocarryoutandhandoverprocedures ,detec of keyfunctionsareperformed byth the receiverendtoreco the received transportblock.Where asthereveres pr physical layerinordertoproduceth received from differenttransportchannels. Pro physical layeristotransform thedatainformati In thephysicallayerofUMTS,WCDMA isadopte 2.9 PhysicalLayer 9 9 9 9 9

Processing gainisachieved Built inredundancy. Multipath signal combining capability. Greater powerefficiency. Susceptibility performance ver thetransportblockandfarthertr regarding transmission andreception and functionalitiestobecoveredby annels, powercontrol, layer inadditiontotheaboveta e. FrequencyHoping(FH)andDi of broadbandinterface. the dispreading process fordatare during dispreadingprocess. e physicallayerinUMTS /WCDMA. e radiosignalstobesent l spreadingiscompleted throughacodewhichisfreefrom the ed atreceiver endtodispread the signal [4]. spectrum systems includingWCDMA.Spread cedures ofdifferenttypesareperformed inthe on intoradiosignals(physical)whichhavebeen allthe users totransmit datasimultaneously. The ead spectrum systems asa tion oferror,channel . InUMTS,airinterface e spreadingmeans theincrease inthebandwidth d asaradioacc (modulated) signalbandwidth of differentspreading codeswhichareallocated ocess iscarriedoutforthesesradiosignals at cient utilizationofava synchronization offreque ansported totheMAClayer.Anumber the antennasfortransmission from sks[2]. Now we shall discuss some sks[2]. Nowweshalldiscusssome ess technology.The rect Sequence(DS)arethetwo radio (physical)layer.Aspecial of theradio(physical)signals trieval even at multiplexing ,mapping of employees DStechnique ilable frequenciesbased result ofdecreasein ncy andtime anda islargerthanthe lower levelsof basic roleof

issues. Insuchasystem amob UMTS adoptedtheWCDMA hierarchal 2.9.2 CellStructure codes. Specificationforcodesinscrambling areasfollows[4]. terminals does notremain necessary. Forscrambli station. Byapplyingscramblingproc different terminals andfordownlink,itisimportant according toaspecificsequenceof codes.Fo and hasnothingtodowiththebandwid Scrambling noisecode involvestheusageofpseudo 2.9.1.2 Scrambling different users. factors (lengths).HenceusingOVSF codesinch the helpofOVSFcodesorthog the datawhichareobtainedfrom OrthogonalVariable The bandwidthofsignalisincreasedinthisop 2.9.1.1Channelization 1MHz.As thefig(2.11)shows,spread chip rate whichisaremarkable increase in A carrierbandwidthofabout5M Chiprate DATA Channelizationcodescrambling code

Chip Rate...... 3.84Mcps Code chiplength...... 38400chips Code length...... 10ms Figure2. ile usercaneasilyhandover. Hen Hz isprovidedinUMTS radi

onality can bemaintained even 30 ess thecoordinationofcodebetw

Spreading andScrambling[4] th of thesignal. In thisprocess, thebitorder isrearranged cellstructuretoresolve th ing processconsistsoftwooperations. WCDMA unlikeothersystems withabandwidthof eration andorthogonalcodesareusedforencoding r uplink,scrambling providesdistinction between

ng codes areselected from for distinguishingdifferent s for encoding data after channelization process s forencodingdataafterchannelizationprocess annelization enablesdiffe SpreadingFactor(OVSF)codefamily. With Modulator ce afterdeployment ofWCDMA the o networks with a fixed 3.84Mcps o networkswithafixed3.84Mcps e performance andcostrelated after usingdifferentspreading een basestationanddifferent cellsofasinglebase theGoldfamily of rent data rates for

and gratercellsimprove thecoverage famous standardsaredeployedincellularnetworks. installed insuchimportant places where there is area jointly cells havebeenselectedformorepopulatedarea which made small cellsandhigherlayerhaslargear UTRAN. Hencebothlayers establish cellstofollow thecriteria i.e. lower layerhas smaller area satellite coverage andtheotherlayer whichpr There aretwocategoriesinlayerdivision.Thehi coverage forUMTSsystems. densely populated areas. Fartherhierarchal layerstru populated areaswhilemicro cellshavesmaller c coverage and users.Thesearemicro andmacro cells.Macro cellscoverlarge areasandless hastwo structure cell hierarchal mobile communicationatmosphere accepted such

with macro cellstoen

Figure2. types of cell whichprovided hance thecapacityin insame geographicalregion[2][14].

31

UMTS cellstructure[2][14] aneedforhighcapacity ovides support forterrestrialradio accessnetwork with respect to users. Micro cells support large with respecttousers.Microcellssupportlarge overage areaandareusedforthecoverageof Small cellsincrease thecapacity geographically ea whichisspecifiedforlargecells.Sosmaller cture isinstalledtopr ghest layerwhichisspecifiedforplanetand a HierarchalCellSt mostpopulatedareas. two typesofservicesregarding (airport). Hencethesetwo ovide globalroaming and ructure (HCS).WCDMA AndPicocellsare

switch betweenthesesstates. different functionalityofcontrolchannel.Conn massage isbroadcasted totheuserincell.In also activatedthroughnetworkby massage issentbyRACHtransportchan which synchronization andbroadcastchannel.Idlemode is effects whichusuallycause problems. which exhibitsmultipath diversity for small cells Usually allCDMAsystems havemultipath divers 2.9.6. Multipathdiversity the Picocell.OneofbigadvantagesTDD delay TDDsystems aremoresuitablefor any envir collision can occurbetween transmitting andreceiving time slots[16].Duetosmall propagation TDD modethereisnopropagation techniques aresame regardingperformance however division multiplexing.FDD needspairband inboth WCDMA system involvestwoduplexingmethods su 2.9.5. DuplexMethod referred toassoftcapacity[16]. be reduced.Thisshrinkingcellis cell whichaffectsthewholenetwork.Raisingcapaci UMTS network,everynew usercreatessome extrainterference foralready existing users within the cellular system hassomecomplicat speed channel wheremultimedia massaginglike serv the world.Soaim ofUMTSistoovercome theba radio access networkofUMTSwhich isbased on CD generation isaiming atproviding Capacity andcoverageplayanimportantrole 2.9.4. Capacity [2][15]. URA PCH terminal is turnedon itchooses asuitable in active position and canbeadjusted with the is unable toaccess theUEtogetany information but There aretwo modes inUTRAN,whichareconnecti 2.9.3. CellState These statesarecomprised of highspeeddata,largebandwidt covered by thenearestcell.InWCDMA themechanism is also usingthismassage whichiscoming from NAS.Thispaging ed issuesregardingexchangebe delaybetweenabasestation nel to start the RRC connection. RRC connection is RRCconnectionis nel tostarttheRRCconnection. is its symmetric dataflowin both directions. is itssymmetric radio resourcemanagement usersareabletocontrol ecting mode thereareforRCCstatesandUEcan in wirelesscommunication networks.Thenext cell inaccordance with [2].In wirelesssystems therearesome multipath direction (uplink and onment.TDD mode isalso controlWhenmobile channelof specific cell. ; therearesome differen ity property but WCDMA istheonlysystem ng mode andidlemodel.Inmode UTRAN sic necessityofusers a authorized onlyfortransmission asaninitial on the othersideidle mobile terminal remains ch astime divisionduplexingandfrequency ices isavailable.Radiointerface ofCDMA MA isalreadylaunched inthemost partsof ty andincreasingloadcause thecellsizeto Cell DCEH,FACH,PCHand h andvoiceconversation.Actually tween capacityandcoverage.In and mobilestation.Asaresult downlink). Bothduplexing ces between thetwo.In nd alsoprovideahigh responsible to allocate the characteristicof

broadcast channel(BCH) power isneeded tobeset inth value which ismost suitablefor receiver. Thisalgor loop andoutercontro WCDMA systems containthreemainpowercontro So thepurpose ofdevelopment ofpower control is the basestation duetonear fareffectswhereallm effect causesproblems inWCDMA system. Itis ve are located “near“and“far”tendtocommunicatein Power controlprocessisveryimportant forWC 2.9.7 Power Control exact informationofSNRandalsoph quality. ThisprocedureisknownasMaximum Ra compensating itssignal strength and alsotime delay several partsandalsophaseamplitudech figure ofthesymbol. Basedonsupportofrotatorand phase rotatordelayequalizerandco components ofrakereceiverblock arematch filter, realtors are used.Rake receiver isusedto principle which isusedinrakereceiver calledmu reflection from obstacles.Multipath cantakeplace which cause performance improvement. Areceivedsi One ofthemain featuresofDSSSsystem isits Figure2.

32 it iseasy to calculate desired powerlevel. l algorithms. Inopen loop pow

Power Control toResolve N e uplinkdirectiononly.Duetopath mbiner. Phaserotatorisresponsib ase ofsignal(d identify the powerful multipath element. Themain anged bychannelestimati received signal through differentmultipath channels DMA atmosphere. When anumber ofuserswhich ltipath diversity principle inwhichanumber of co- obile terminalssendsignalsatsamefrequency[8]. to provide supportforairinterface physical layer. tio Combining (MRC).Hereitneedstoknowthe due toreflection,diffraction and scattering. The ry important toovercome l algorithms whichareclose(inner)loop,open iversity)[2][16]. ithm isusedininitialstage wheretransmission codegenerator, co-realtor, channelestimator, of different elements jointlyincrease itssignal a single seem BS,thenduetonear-farfield ear Far Field Effect [8] Effect ear FarField equalizer, itiseasy todivide itsenergy in gnal hasdifferentvariations duetosome er control,UEiscapab loss, SIRInterference incell and le foradjustingtiming inevery on .Henceattheendby the receivedpowerat le tofixaparticular

in differentchannelslike RACH Closed looppowercontrol provides [4]. channels inoppositeway [2] Open looppowercontrolworksonlyinthatenvironm loop. relation toachievetheSIRtarg Inner looppowercontrolisalso responsible tofixtheBLERstandardwhichisex Outer looppowercontroliscarriedoutinth BLER DL PT.UL DL SIRTargetadjustment PT.DL and some atmosphericchangessuchasline into asuitablevalueofSNRand Power controlouterloopfunction POWERCONTROL DL OUTERLOOP

Figure2. andFACHin et. Innerlooppowercontrolwork

interference. Thisvaluedepends 33 responsibletocompensate th is calculated withsignificant va better solutionincaseof slowfadingwheresome changesoccur

Inner andouterLoopPowerControl[2] POWER CONTROL POWER CONTROL POWERCONTROL INNER LOOPULOUTER TX POWER TX of sight(LOS),Nonline(NLOS). both directions. e direction of uplink at RNC where UTRANis e directionofuplinkatRNCwhere ecuted indownlinkdirectionbymobileterminal. SIR UL ent wherethereisnoavai BLERUL e suitabletransmission powerin s forbothopenloopandclosed on featuresofphysicalchannels lue such asblock error (BLER) LI Target adjustment ULSIR lability offeedback

simply rejected. In unacknowledgedmode, errorcorrectiondoesnottake RLC layerensures error freetransmi In acknowledgemode thisRLClayer induced. Ithasthreemodes foroperation. Radio LinkControl(RLC) sublaye 2.11UMTS RLCLayer Multiplexing of datastreams inthelogi Encryption ofthedataintransparentRLCmode. Providing information ofcurrentstatetoRRCsublayer. also performed bytheMAClayer. decision forsendingdatapacket(next)isbeing (physical). IntheMAClayer,different steamsof The main functionoftheMaclaye 2.10. UMTSMACLayer trans Tasks ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ

No segmentation ofdata If common areused,iden channel Ciphering (iftransparentRLC-mode isused. Monitoring ofthetrafficvolume. Priority handling/scheduling. Selecting ofappropriateTransportFormat (TF). Mapping oflogicalchannels Provisioning oflogicalchannels. p

that ort Figure2.

channels

are

related

34

UMTS MACLayer[10]

to

ssion ofdataincorrectsequence. the requests fordetectionof errorfo r is tocoordinate the transmission of datatothemedium r guardsdatastreamsofdiffere cal channel tothetransport channel.

data

multiplexing totransport channels. carried out intheMAClayer.Following tasksare

tification ofbyUEthe dataarehousedintheform ofqueues.Actually

place rather the data of

logical

channels r datablocks.Inthismode the nt typesfrom errorstobe

to

packets witherrorare

[17]. as thehandoverprocess. Theneed Actually, the switchingmobile of us handovers inUMTS. interference byprovidingstrong load within different cells, thefacility of roam mobility, provision of continuityof services and An efficientandeffectivehandovermechanism is re a usermoving incellularnetworks. crosses the boundaryof acelland enters anew cell. It session withoutdroppingorany Handover canbedefinedasprocedureorstrategy 2.12 HandoversinUMTS this mode isveryusefulfortransmi In transparentmode thedataisforwardedto THE RADIO LINK CONTROL LAYER THE RADIOLINKCONTROLLAYER Tasks ƒ ƒ ƒ ƒ ƒ ƒ ƒ

Ci Flow control. Segmentation/reassembly. Transparent modetransf contemporary) Unacknowledged mode transfer(error-free,singleness, singleness) Acknowledged mode transfer(ARQerrorhandling,order, 3 transfermodes.

that p Figure2. herin

are

g related

35 ( onl

Radio LinkControlLayers[10] y discontinuity whenthemobile us ofhandoverforanongoing callem

non-trans to ssion ofaudioandvideodatastream[10]. connectivity totheBSisam er toanother different channel without interruption isreferred to

the

protected er.(no errorprotection) p arent services MAC layerwithoutaddingtheseparateheadertoit ing between differentnetworksandreductionin ing between

by whichanongoingcallismaintained orheldin transmission maintainability of QoS.Moreover, balancing of quired inUMTSnetworkstoensureadvanced canrightlybe termed ascriteriaofmobility of )

of

data. er ismovingatahighspeedand ongst thedesiredoutcomes of erges duetofollowingreasons

place within differentCDMAsystems, itis this typeofhandoverscan be Techniques (RAT)orinotherwa This isthetypeofhandovers which takes place 2.13.1.4. Inter-SystemHandovers: handover. difference ofthevaluesWCDM WCDMA system, itisalsoreferredtoasIn techniques. Iftheintra-system ha can beobservedinFDD-TDDdualmodetermin Intra-System handoversarethosewhichoccurin 2.13.1.3. Intra-SystemHandovers: channels belongtosame core network. one channeltoanotherandtheaccesstechnology Unlike verticalhandovers,ahorizonta 2.13.1.2. Horizontal Handovers: of callbetween twodifferentaccess technolog handover usediscalledverticalha technology thanthatitisalready When auserwithongoingcallis 2.13.1.1. VerticalHandovers: Different typesofhandoversin 2.13.1. TypesofHandoversinUMTS other thanUMTS. iii) When amobile userchanges it cell. ii) Number of usersinaparticular cell increases in i) Theusermovesfrom area of onecelltoanothercell. a handover between WCDMA and ahandoverbetweenWCDMA UMTSarediscussedbelow. ndover takesplacewithin y differentRadioAccessMode(R subscribing, theninordertoretain ndover. Henceaverticalhandoverca A carrierfrequencies,thehandover s positionsuch that itenters an required toenteranareaofc l handoveristheoneinwhichtran also referredtoasInter-System handover. ies forexample UMTStoWLANorGSM. als wherehandovertakes tra-frequency handoverwhileforthecellswith a singlesystem only[18].Intra-System handovers acasewhenalreadycallisinprogressthat for boththechannelsissame andboththe within thecellsofdifferentRadioAccess the cellswithsimilar AM). Commonly anexample for GSM. When thehandovertakes overage of the different access overage ofthedifferentaccess area withaservice or network thesessionofca is saidtobeInter-frequency n be explained as a transfer n beexplainedasatransfer sfer ofcalltakesplacefrom place from FDDtoTDD carrier frequencyin ll, thetypeof

widely adopted. cells( usingmore than onechannelatatime). complex hardwareandincreasedoverhead becaus considered anadvantageofthishandoverandthedi Soft handoversgivelowercalldr the source cell isretained for some time even connection tothetargetcellismade beforedisc It isamake beforebreaktypeofhandoverswh 2.13.1.6. SoftHandovers: hand, calldroppingprobabilityismuch channels atatime. Thischaracteri complexity ofhardwareformobile isreducedas In hardhandovers,more thanonechannelatatime either asinter-frequencyor bearer whereasitsoccurrenceremains losslessfor user doesnot getaffected.Ashortdisconnectionta the connectionintargetcellismade that.Ifitoccursasaseamless after handover,themobile It isabreakbeforemake typehandoveri.e.thec 2.13.1.5. HardHandovers: intra-frequencyhandovers.

stic canbeviewedasanadvant opping probabilityandreduced Figure2. higherforhardhandovers[19].

36 after acquiringthechannelfrom thetarget cell.

Hard Handover[20] onnecting from thesourcece onnection in thesource cell is In UMTS/WCDMA systems, soft handoversare InUMTS/WCDMAsystems, soft ich wasactuallyadopted itwouldhavebeenin thecaseofreceiving two kes placeintypeofhandoverregardingreal-time- non real-time-bearers. Ha e ofsimultaneousconnectiontomore thanone cannotberetainedbyauserthatmeans thatthe sadvantages ofthistypeincludecomparatively age ofhardhandover.Ontheother interference [21]whichcanbe in CDMAsystems. The rd handovers can occur rd handoverscanoccur ll i.e.theconnectionto disconnected firstand

that onlyonepowercontroll frequency handoverasitusesthe single basestation,thet In caseofmultipath effectswhenmore thanonesi 2.13.1.7. SofterHandovers:

ype ofhandoveriscalledsofterhandove Figure2. oop worksinitactively[16].

Figure2. one carrierfrequency.Anotherfeat

37

Soft handover[20]

38

Softer Handover[20] gnal (multiple copiesof signals) arereceived bya

r. Itcanbetreat ure ofthistypehandoveris

ed asaninter-

below [22]. of PPTandPTtomultiple connections.InUMTS, different accesspoint.UMTSoffersconnectionlessas communication, text,andbearerservicesinorde Here weshall discuss some important services 2.14 UMTSServices evcs Datarateinkbps Indoor andlow rangeoutdoor Urban Outdoor Satelliteand RuralOutdoor Services

Table

2.2

UMTS Services offeredbyUMTSnetw r toenablethetransf 384 Kbits/s 144 Kbits/s 2048 Kbits/s different dataratesoffe wellasconnectionorientedservicesincase

er ofinformation among ork inincludingvoice red aregiventhetable

traffic todifferentkindof user With economy andprecision,WiMAX willmake thedelivery ofbroadband data, video andvoice following aspects.[23] shortcomings anddeficienciesof the lackofeconomies inbroa ofscale the adaptation ofproprietaryairinterfacetechnologi countries regardingfrequencyal healthy competition due toanumber of reasons.Thedifference in theregulations of different present and facedbythe industry.Also,dissatisfactio In earlygenerationsofbroadband,discrepancies given topoint-to-multipoint t larger geographicalareaswithbroadbandservices, considerable longperiodoftime. Duetoecono providing classtechniquefortheconnectionofl Typically, point-to-pointradios(abroadbandwire 3.2 Background instead ofcableandDSL. over theworld.Ithascapacityofproviding deployment ofWiMAX technologyhasmade th high development ofWiMAX technologywhereas W 3.1 Introduction ™ ™ ™ ™ ™ ™

WiMAX. Wireless Metropolitan AreaNetwor orldwide Interpretability forMicrowave A Large scale operation and interpretability Independent oflinesight Cellular networksimilar coverage Licensed andunlicensedfrequencyspectrum Shared bandwidthupto100Mbps CPE andBScost echnologies bythewirelessnetworkoperatorsforalongtime. s andcustomers possiblefor these location andusagepulledthemanu previous technologiesareattempte Chapter WiMAX WMAN standard is based on IEEE 802.16 .The WMAN standardisbasedonIEEE802.16.The dband ascompared toothertechnologies.The my, higherflexibilityandcapabilityofcovering "LastMile"broadban less technology)which ccess iscommonly abbreviated and known as a higherattentionandprio

ong haulnetworkshasremained inusefora like less serviceability withhigher costswere 3 n wasthereinindustrial es. Allthesefactors wereheldresponsible for roughput possibleoverl

king (WMAN)providesthebasisfor

rvice providers.Astheequipment d tobeaddressedinWiMAX in facturers ofequipment towards d wirelessaccess(BWA) is awellknownservice circlesastherewasno rity ofusagehasbeen onger distancei.e.all

tolerated jitter[27] this standard.QoScheck standard. ProvisionofdifferentialQu Frequency DivisionDuplexing (F QPSK, 16QAMand64modulati (SC) in10-66GHzbandoffrequenc assigned forphysicallayerandMACinthis In pointtoandmultipoint comm 3.3.1 IEEE802.16-2001 evolution ofthestandardisstatedbelow. itgotapprovedbytheworkinggroup 2005[26] and frequency bands[24].anamendment was intr This specification also provided support for multimedia servicesbothinlicensedandlicense exempt feature ofthisstandard wasits present versionofthisstandard introduced intothisversionbecauseofnewf broadband wirelessaccess(BWA).With thepassage about thespecificationsofbothphysical (PHY In thefirstversionofIEEE 802.16-2001[25]standa regulated bythisworkinggroup. andwirele associated standardsfor1EEE802.16 specify the standards forfixand mobile broadband solve theproblem withinIEEE802.Theeffortsha IEEE802workinggroupwasesta (NIST) in1998.[24].An bed (N-WEST) intheUnited States eradicate theproblem, ameeting wassummonedby the equipment manufacturers ofdifferent aroused scenario, theissueofunavailabil started todevelop andintroduce devicesande 802.16 standardsandcanrightlybetermed asasubsetofIEEE 802.16. WiMAX isentirelybasedontheIEEE 802.16standard 3.3 EvolutionofWiMAX and usingprecise frequency bandswillbecome possibleensuring the economy of scale. employed inWiMAX isbasedonstandards andinte By theendof1990’s,anumber oftheequipmen are specifiedbyserviceflows and is carriedthroughaservi wasapprovedin2004andcombines specification oftheai ity ofanyinteroperablestandard DD) andTime DivisionDuplexin ofAmerica's theNationalInstit ality ofService(QoS)forMACla y isadoptedinphysicallayer. on techniquesareusedinthisstandard.Thesupport forboth oduce to IEEE 802.16-2004 known as IEEE 802.16e IEEE802.16e oduce toIEEE802.16-2004knownas eatures andutilizations.IEEE 802.16-2004[24]isthe unication [25],forfixedBW quipment forbroadband wirelessaccess.Inthis ) andmedium accesscontrol (MAC)layersfor ce flowID.Parameters likemaximum latency and and facedbytheindustry.inordertodiscuss firstly issuedstandard.Singlecarriermodulation t manufacturers fortelecommunication industry ve beenmade workinggroupinorderto bythe rd whichwasapprovedin2001,theinformation wireless access .Allthe ss MAN air interface are being developed and ss MANairinterfacearebeingdevelopedand roperable hencethegoalofachievinglowcosts TheNationalWireless ElectronicSystems Test oftime many changesandamendments were their correspondingQoS parameters. IEEE 802in2006.Adetail r interfaceforfixedtypebroadbandsystems. .it contain allthenecessa blished asaresult for linkageandop ute ofStandardandTechnology all previousversions.Themain g (TDD)isprovidedinthis yer isasignificantfeatureof related amendments and A, specifications are nd itwasdecidedto ry featuresofIEEE ed overviewofthe eration between

Connectivity isalsoprovidedinit delivery oflastmile. Wireless broadband accessasan approved. ItisalsoknownasfixedWiMAXstandar named IEEE802.16-2004.Allthespecificationsprovided In 2004,allthepreviousversionof 3.3.4 IEEE802.16d-2004 frequency bandindetail. corrected inthe.16cstandard IEEE802 Thediscrepanciesanderrorsinthefirs 3.3.3 IEEE802.16c-2002 of usingOrthogonalFrequency to multipoint topology.Alongwithsi enhanced. Moreeverthisstandardprovidedan features compulsoryinthisst management techniqueandadaptiveantennaarra multipath propagation problem whichwasaddre range whichmade NonLineof Geographical coveragecapacityofthenetworkwa provided asaresultofthis The IEEE802.16workinggroupapproveditin2003[25] the Medium AccessControl layer to standardwasamended bythisstandardandimprovementThe IEEE802.16-2001 introducedto was 3.3.2 IEEE802.16a-2003 andard unlike802.16-2001wherethosewe in 2002[24].thisstandardprovi Division Multiplexing(OFDM). amendment forlicensedandlic along withLineofsightconnectivity Sight (NLOS)functionpossible. thestandardwerecombine andconsolidatedinanewstandard supportextraandmultiple specific ngle carriermodulation (SC),this option forsupporttomesh ys [25].Bymaking anumber ofprivacylayer s enhancedduetoInclusionoflessthan11GHz ssed byaddingfeatures like advanced power d. Providing72Mbits/s,thisstandardenablesthe t versionofthestandardwereremoved and alternativeofDigital SubscriberLine(DSL). . Support for 2-11 GHz frequency bandwas . Supportfor2-11GHzfrequency by previousversions des system profilefor10-66GHz ense exempt band. frequency The standard sufferedfrom Thestandard . standardprovidesanoption re optional,thesecuritywas ations ofthephysicallayer. topology alongwithpoint wereendorsedand

Europe: ETSI HiperMAN China: CCSA Korea: WiBro standards Korea, provides fullsupportfor mobility. bands whichofferhigher throughputthan802.16dproducts higher throughput.Itisoptimized (SOFDMA). ItisusedforgrounduptheHipe for quality ofserviceanduses Scalable 802.16-2005, thisistheamendment of802.16-2004.IEEE It isalsoknownasmobileWiMAX. Mobile 3.3.5 IEEE802.16e-2005

China

coverage

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802.16

Figure

8 ( 8 (

8 8 8 8 2 2 8 ( 8 ( 8 0 8 0 ( ( 2 2 0 0 0 0 H H 0 2 2 0 2 2 0 2 0 2 0 0 2 2 2 2 2 0 0 2 0 0 2 2 2 . 2 g . for dynamic mobile radiochannelsandwiderrangesofunlicensed g 0 0 . . 1 . . 1

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Fixed broadband wireless airinterfaces 10-66GHZ 0.6 mnmn ie bodad iees A and MAC wireless PHY 2-11GHZ broadband fixed 802.16 amendment Orthogonal Frequency Division Multiple Access WiMAX coveredby802.16e standardorIEEE is 802.16 802.16 (Formerly Profile Fixed Licensed Broad Fixed Manageability rMAN givinglongerrange

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spatial multiplexing. Using MIMOsystems of adaptation of multiple antennatopologies and sc Multiple input andmultiple output (MIMO) isstronglysupported by WiMAX whichpermits 3.4.6 AdvanceAntennaTechniquesAdaptation increased byflexibleschedulingand by usingsub channelization and multiple ordifferent codingmethods. QoScanbeimproved and In WiMAX architecturetheMAClayeris responsibl 3.4.5 QualityofService(QoS) frame basedinformation [28,29]. accordance theirdemand. Themethod ofresourceallo base station byascheduler. TDMscheme isem depending upontherequirement ordemand oftheuser. In WiMAX, averyflexibleand 3.4.4 perUserResourceAllocation preferred. to duplex FDD[24]issupportedinWiMAX.Due Both TimeDivisionDuplexing(TDD)andFreque 3.4.3 TDDandFDDSupport techniques. noise ratio,adaptivemodulati Employing AMCthroughputcaneffectivelybeincrease and Forward ErrorCorrection Connection totheincreasednumber ofusersisa 3.4.2 AdaptiveModulationandCoding(AMC) multipath and enablingoperation inNL Orthogonal FrequencyDivisionMultip The principleoforthogonalityprov 3.4.1 OFDMBasedPhysicalLayer [28, 29,30] WiMAX Ubiquitous. Significanceof capability tosupportdifferentsystems ofarchitectur regardingdepl a higherdegreeofflexibility WiMAX canrightlybeviewedas 3.4 SomeSignificantFeaturesofWiMAX (FEC) codingscheme [24]. on andcodingscheme requires dynamic method forresourcealloca anemerging wireless broadband accesstechnique whichcontains ides thebasisforoperation using dataratesinhigherdegrees. is elaboratedinsome ofits lexing (OFDM),whichhasachar OS environment [28]isadopted. oyment andoperationalusage.WiMAX hasthe hemes likespace time encoding, beam forming and ployed tosharecapacityamong multiple users in ttained intheWiMAX us antenna deployment attransmitter andreceiver ncy Division Duplexing (FDD) along withahalf ncy DivisionDuplexing(FDD)along e forQoS[28].Endtoendcanbeachieved flexibility andlowcomplexity TDD ismostly e i.e.point topoint, pointtomultipoint and cation isveryflexibleandprovides frame by It isactuallyexecuted d. With higherdatarateandlowsignalto highest andadvancemodulation following distinguishingfeatures. of WiMAX inphysicallayeri.e. of WiMAX tion isadoptedforeachuser acteristic propertytoavoid ing adaptivemodulation and controlledinthe

and security. provide allendtoservices wh The network architecture of WiMAX iscompletely ba 3.4.12 IPbasedArchitecture Extensible AuthenticationProtoc (AES) isusedforsupportingstrongencryptionwith The mechanism ofsecurityadop 3.4.11 Security scheme isusedin10MHzspectrum inarationof3:1downlinktouplink. Remarkably highpeakdatarate 3.4.10 HighDataRate rate inWiMAX isfullysupported. be scaledwithrespect to availablebandwidth [ according to available bandwidth ofchannel.inOF In WiMAX thescalablearchitectu 3.4.9 Scalability mobile WiMAX. Mobileapplica Support fortheseamless handoversin 3.4.8 Mobility supported in WiMAX ifrequired. is used tobe retransmitted automatically. Hybrid in case ofpacket lostno acknowledgement isr increased reliability[24].Thetransmitted packed is Link layerofWiMAX supportsAutomatic Retransm 3.4.7 LinklayerRetransmission employed. spectral efficiencyandoverallcapaci • • • •

Sub channelizationforuplink Power control Frequent channelestimation Power saving mechanisms tions ofWiMAX alsosupport are supported in WiMAXare supportedin suchas ol (EAP)isselectedforafl ich dependonIPprotocol forQo ted inWiMAX isveryrobust.AdvancedEncryptionStandard re ofphysicallayerenablesthe ty ofthesystem isimproved delay tolerantmobility applicat eceived from thereceiver andthetransmitted packet 27,28] andhencescalability forbandwidth anddata -ARQ i.e.amixture ofFECandARQcanalso be requiredtobeacknowledgedatthe receiverand DMA, thefastFourier transform (FFT)sizecan robustprivacyandkeymanagement protocol. sed onIPplatform.architectureisusedto ission Requests(ARQ)inordertoachieve exible authentication[27.28]. as theabovemention schemes are 74 Mbpsat20MHz [28].TDDis S, mobility, session management data ratestobeeasilyscaled ions likeVoIPisprovidedin

technology fasterandmore widely.Aparallelcanbe common platform willlowerthecosts and enhance WiMAX systems implemented byvariousvendors w equipment companies, describes theinteroperability ForumWiMAX [32], anorganizationofleadi 3.2. included. Hence,WiMAX can beknownasasubset mandatory inWiMAX, andoptionalfeaturesin IEEE 802.16standardprovidesthe already availableatthe internetwi like VoIP,IPTV,streaming applicationsandIntern overhead byemploying asingle pr circuit corenetworkisab The prepositionthat WiMAX isall-IP, means that Physical and theMedium A throughput overlongdistances.Two layersinthe properties. Mainly,WiMAX define very much to thetraditional (BWA) asanalternative tocableandDSL.Itis 802.16 standard[31].Itisatechnol WiMAX isaguaranteemark thatpa forproducts 3.5 TechnologicalAspectsofWiMAX sent infavouroftheIP Figure ccess Control(MAC)layer.

mobile telephonesystem, thoughit

3.2 ll beavailableforuseoverWiMAX.

otocol. Dueto this reason WiMAX iswellsuited for IP-services Representing WiMAX assubsetofIEEE802.16 [31] ogy, enablingthedeliveryoflast s anall-IPbasedarchitecture, basis forWiMAX. Allmandatory featuresin802.16arealso

IEEE

WiMAX

802.16 packetnetwork.Also,itre apoint-to-multipointarch ng operatorsofcommunicationscomponents and IEEE802.16may mandatory ornot beoptional, OSI-stack aredefinedbyWiMAX, whicharethe ss compliance andoperabilitytestfortheIEEE a common IP network core is used, where the acommonIPnetworkcoreisused,wherethe oftheIEEE802.16standard andcompatibility specifi et surfing.Thismeans thatserviceswhichare drawntothesuccessof ith different equipment willinteroperate. The performance, thusthemarket will adopt the

whichprovidessupportforhigh mile wirelessbroadbandaccess differs inspecificationsand itecture, whichresembles duces thecomplexity and WiFi, aWireless Local cations andstandards. as illustratedinFig

systems.[28] features likeflexiblechannel characteristic andalsotherange.TheIEEE802.16d channelization (limited) intheuplinkdirect Performance aswelltherangeoffi number ofsubcarrieris time isreducedalsowhichcausedbydelayspr varies some times regardingsubcar are usedforguardband.3.5MHzbandwidthchanne information. Eightpilotsubscriber In fixedWiMAX, FFTsizeis25 utilizing different frequencies in In short,wecansay thatacha subcarrier utilizesaseparatefreq high datarateoveramultiplenumber ofspecifi WiMAX physical layer is based multicarrier modulationisutilized reduced. IEEE 802.16discapable to supportmultiple In thephysicallayeroffixedWiMAX, theperforman 3.5.1.1 PHYLayer wireless accessandcansupportnomadic basedontheIEEE802.16dsp The fixedWiMAX profile, 3.5.1 FixedWiMAX 802.16d andIEEE802.16erespectively. Anoverviewwillbegivenforbothsystem profiles. WiMAX whichaddsmobility toWiMAX. Thesepr Two systemprofilesaredefinedforWiMAX. Fixe verification ofinteroperabilityw profiles. WiMAX Forum arrangesmeetings calledpl profiles, andCertificationLabsareusedtoperm which options aretobeutilized.TestingSpecifi WiMAX achieve interoperability, different frequencybandsandaccordingtoregion by The IEEE802.16AirInterfaceSpecificationexplains [34, 35]. Area Network(WLAN) system, specifiedbytheWi

directly proportional to nnel bandwidthisfurtherdividedin bandwidth ,AMC,forwarderror formation oneachchannel,transm ith othervendor’sequipment [36]. on OFDMbasedmultiplexing techniques whichare usedtodeliver uency whichdecreases theinterfer tomanage thesignalforboth time andfrequencydomains [29]. s areallocatedforchannelesti has undertakenthedevelopment of 6 whichisfixedwhere192subcar rier spacing. Whensubcarrier spacing isenlarged thansymbol and portable accesstooinsome cases. xed WiMAX canbeimproved byemployingsub- channelbandwidth.[28] it vendorstoprovethattheirequipment meets these ion. Itconsequentlyimprovesthelinkbudget ead. Bytheabovephenomena itisconcludedthat Fi Alliance [33]basedonthestandard 802.11b/g cations are developed to verify these specific cations aredevelopedtoverifythesespecific d WiMAX wasfirst specified and later mobile ug fests,wherevendorsmeet forvalidationand cally spaced shorter subcarriers, whereeach ofiles arebasedonthe ce ofthesystem isincreasedandcomplexity is standard forfixedWiMAX includeadvanced l isassignedforfixedWiMAX however;it region frequencyregulatory rules.Inorderto accessesforuplink transmission. Where as options foranumberof ecification, ismainly aimed atthefixed mation andsynchronization56 ission cantakeplace[28]. correction andadvanced antenna to severalsubchannelswhereby ence andalsoreduces crosstalk. System Profilesspecifying rier areusedtocarrythe specifications of IEEE physical layers for physicallayersfor

are doneaslistedinTable 3. Many oftheparameters from the Fixed WiMAX part 3.5.2.1 PHYLayer following sub-sections. support mobility areaddedtoboththePHYand (SOFDMA) isadoptedforscalablechannelbandwi interface forimproved performance inmobile mu [37].Mobile WiMAX usesOrthogonal Frequency mobility. Currently, mobile WiMAX followstheIEEE802.16especification of802.16standards The requiredfunctionalityhas 3.5.2 MobileWiMAX utilizes variablelengthMPDUs.[28] reducing theMPDUheader.Inordertomaintain to compatibility with higher layertheconvergence which is capable of interfacing with support aswell. WiMAX MAClayerhasalsointrodu unit (MPDU)tobe delivered through air interface. from thehigher layernamed asMACservicedata The MAClayerprovidesaninterf 3.5.1.2 MACLAYER C A M

Security Sublayer MAC commonpartsublayer Service Specificconvergencesublayer

been introducedbyIEEE802.16especi Figure ace forphysicallayerandtranspor otherhigherlayerpr

3.3

MAC layerofWiMAX [28] theefficienttransmission, MAClayerofWiMAX layer decreases theoverhead forhigher layersby Forreceptionpurpose, unit(MSDUSs). MACprotocoldata Itenables dths [38].Enhancedand lti path NLOSenvironments. ScalableOFDMA Division MultipleAccess(OFDMA) intheair MAC layers, which will be addressed in the MAC layers,whichwillbeaddressedinthe iskeptinmobile WiMAX, butenhancements ced asublayernamed asconvergessublayer otocol likeATM,Inte t layer.MAClayergetspacket fication inordertosupport MAC layer alsoprovides new techniquestobetter rnet , IPetc. Due

scheduler ismore advancedduetomore varyi time-Polling Service.It was mainly introducedtosupport variablesized packets forVoIP.The has thesame supportfor QoSasthe fixedprofilew mobility. This includes powermanagement and The MediaAccessControl(MAC)sub 3.3.2.2 MACLayer with mobile WiMAX toenhancecoverageand Automatic RepeatRequest(H-ARQ)andFastCha Other advancedfeaturesinmobile WiMAX ar NLOS requirement ispossibleto overcome atlowerfrequencies. where DopplereffectsandMultipath fadingarefr For themobile partlower frequenciesareuseddue mobile support,a20-foldincreasein forming, couldincreasecoveragefromtwotoninek The twokeysmart antennamethods favouredbytheWiMAX Forum,MIMOandAASorbeam channelization. sizes are decided for useinS-OFDMA.Theenhanced multiplexing technique addssub choice ofduplexing. OFDM hasbeen enhanced As elaboratedfrom table,BPSKisremoved the Frequency Channel Modulation Duplexing FFT Multiplexing

size

Bandwidth

mode

Table

3.2

Comparing PhysicalLayerin 256 3.5,7,10 BPSK, TDD, 2GHz OFDM thecapacityofsubscriber[39].

FDD, layer has beenenhanced especiallywiththeneedtosupport

to QPSK,

11GHZ MHz Fixed

HFDD

16, capacity for WiMAX inmobile applications.

e AdaptiveModulationand bytheOFDMAmultiplexing technique.TwoFFT ng conditionscausedby themobile environment.

WiMAX

handover betweenbase stations.MobileWiMAX as analternativeformodulation. TDD istheonly 64

nnel Feedback(CQICH).Thesewereintroduced ith the additionofthe Qo ilometres radiusforanurbanbasestationhaving toimproving deployment ‐ equent. Radiosignalspe QAM Mobile andFixe

512,1024 5,7,8.75,10 2.3GHZ QPSK, TDD

SOFDMA Mobile

d WiMAX [39] d WiMAX

16

to

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, WiMAX

S profileenhancedreal 2.5 64

netrate betterandthe MHZ in a mobile channel, ‐

QAM GHZ

required tobeviewedseriously. interoperability forroaming, multi-vendor acce functionality isneededtosupport truemobility. mobility. TheIEEE802.16e specifies Based onthestandard IEEE802.16e, mobile WiMA 3.6 ArchitectureofMobileWiMAX unicast messages andtrafficfrom multiple Base MS toallthe Basestations andviceversa.AMDHO where anactivesetiskeptintheMSandBase (make-before break).ThirdlyanoptionalMacr monitors theactiveset, and MSmaintain an active set, (break-before-make). Thesecond and optional is Handover, wheretheconnectionwith theBSisendedfirstbeforeMSswitchestoanother to obtainmobility.Threemobility modes ares the MStoBS.Powerusageandradioresour idle mode. Thesecondissleepmode, wherepre- registration toaspecific the mobile station(MS) onthemove onlyisava duration. Twomodes forpowereffici Battery isacriticalsubj to thestrongestsub-channelsthatar selective schedulingisalsosupported,wheremobile may bechangedonaframe-by-frame basisinres Downlink anduplinktraffic.Dynamic ResourceA transmission overthetime-varying channel.Asin withHybridAu and coding(AMC)combined conditions. Fastchannelfeedbackisprovidedby Available resourcesarescheduledinresponseto andperformshandoverbasedonthesi ect inmobile devices,and BS. Handoff management willthereforenot BS. Handoffmanagement which isalistofBasestati e composed ofthebestsub carriers. ent operationarethereforeadded. the MACandPHYlayers,but specificationfor network layer o DiversityHandover(MDHO) stations inthe same time interval [33]. ces areminimized. Handovermust tobesupported stations andtransmissions theCQICHchannel,andadaptivemodulation ponse totrafficandchannelconditions. Frequency Fast BaseStation Switchi negotiated periodsofabsenceareannouncedfrom ss networks and inter-company billing[40] are upported. Thefirstandonlymandatory isHard ilable forDLbroadcasttrafficmessages without thefixedpart,schedulingisperformed forboth Aspects such asinter-network and intervendor llocation issupported,wh should be spared as much as possible for longer forlonger should besparedasmuchpossible to Repeat Request (H-ARQ) providerobust to RepeatRequest(H-ARQ) userswithfixedresourcedemands areallocated bustydatatrafficandtime varyingchannel startswhenaMSdecide X isspecifying asystem willsupport that ons involvedintheFBSS.TheMS gnal strengthfrom CQIchannel the be considered if theMSis in The firstisidlemode, where ng (FBSS)wheretheBS areperformed fromthe ere resourceallocation s totransmit orreceive method may beused,

be identifiedbytheNetworkReferen security and multi-vendor interoperability. Alogical [41].Several aspectsareconsidered,whichroug Service ProviderWorking Group portable andmobile WiMAX systems beyondthest Forum NetworkWorking Groupcreat havethereforeformedWiMAX twoadditi forum MS SS/

Another R2

ASN ASN R2

R8 R4

Figure

3.4

ce Model(NRM)asshowninFigure3.4 which linksserviceprovider Visited Mobile WIMAX Reference Model[23] Mobile WIMAX Reference es higherlevelnetworkingspec

or ASP

Internet

Network CSN

NSP hly summarized aremobility andhandover,QoS,

onal workinggroupsforthesepurposes.WiMAX

representation of thenetworkarchitecture can andards specifications.Theotheroneisa Home

or ASP participation withinWiMAX

CSN Internet ifications forfixed,nomadic,

NSP

Network

with optionsforwirelineand/orwirele macro base-stations.Optionsforwhichbackhauling technology tousewillbeflexible,forinstance selection of networkarchitecture. aspect forsystem diffusion.Operators willhave a Interoperability ofequipment frommultiple diffe Agreements (SLA). defined bydifferentNetworkSe Serve). Bandwidthmanagement andadmission contro supported throughoutthenetworkbyQo per service flow for theMobile Stations. Services networks. Extensive QoSsupportisofferedin supported forIPv4orIPv6.QoSwillemerge tobe as for instanceWiFi and3Gsystems willbepr Handover-support betweenWiMAX NetworkServiceProv Service Providers.Mobilityandhandoverswillbe Provider (NSP),wheretheamount andtypeofprovi and operationwillbeimportant. Thelogicalentity may alsobepresentinaCSN.Contentservices and proxies.Gatewaysforinterwor level. Authentication,Accounting a provides IPconnectivity(L3).Connec within the ASN,before thecontrol ishandle logical businessentitieswhichcontrolsanddepl Several ASNsmay belocatedwithin aNAP.AS and mobility betweenbase stations. ASNsarelo Access Control(MAC)functionsforstation-loca stations and oneorseveralASNGateways.Inte A MobileStation(MS) isconnected withan Forinstancehowtodesignth king withothernetworksandMobi rvice Providers, willbeimpl nd Authorization(AAA)isadminist ss technologieswith tion tointernetthroughgateways S mechanisms asforinstance DifferentiatedServices(Diff- d toaConnectivity Service Network (CSN)which the WiMAX radioaccessdomain, bothperMSand Access Service Network (ASN)consistingofbase as wellIMSservices,supportsystems forbilling rface R1,betweenMSandASN,involvesMedium ting, paging,RadioReso Ns manage theradiolinks,whereasNAPsare cated within a Network Access Provider (NAP). cated withinaNetworkAccessProvider(NAP). rent vendors,withinandacrossASNs,isakey oy theASNs.Layer-2connectivityisprovided ovided. Mobilityisarequirement andmay be are differentiated and willhave theabilityto be widelysupportedinth scalable, extensible operationand flexibility in ded functionality willdifferinvariousNetwork maintaining the CSNisaNetworkService an importantsubject infutureandpresent l isaddressed. Policiesregarding QoS,as differentquality iders aswell aswith emented throughService Level e networkwithPico,micro and le IPHome Agents(MIP-HA) rated in this entity by servers rated inthisentitybyservers androutingiskeptatthis urce Management (RRC) e networkarchitecture. othertechnologies

3. MacroDiversityHandover (MDHO) whichisalsooptional. 2. FastBaseStationSwitching 1. HardHanover(HHO)whichismandatory. IEEE 802.16egivessupportforthreemethods 3.8 HandoversinWiMAX features possiblyavailableformobile endusers. [42].Mobile WiMAX hasmade thehighqualityvi some specificationswhichdescribe anodefo has anbuiltincapacitytomanage handoversat has benefitedthemobile endusersinaccordance in moving positions anywhere .AnallIPbased (MWBS) inWiMAX. Itenablesthe provisionof mob The IEEE802.16estandard 3.7 MobilityinWiMAX

provides thespecificationsforM Figure (FBSS) whichisoptional.

3.5

WiMAX networkarchitecture [28] of handoversinmobile WiMAXnamely, higherspeeds.NowWiMAXForumhasprovided r mobility support andtermed asASNGateway mobile broadbandtechnology i.e. mobileWiMAX with theIP-specificoptimizations of802.16[42].It deo downloadingandvi ility(seamless) toenduserswhilestationary or obile Wireless BroadbandServices deo conferencinglike

MS[28] reported toCQICHbythe in suchawaythatnoexplicithandoff signalling is communicates withtheMS.Theconnectionisshifte with each basestation ispr involvement inhandoverprocedure.Rangingisperf holds theactive setin FBSS whichisactually the in In FBSS,aconnectionisretainedby theMSwith 3.8.2. FastBaseStationSwitching (FBSS) has beenmade andtheconnectionwith the pr with [28]. Synchronization can connecttooneormorethanbasestati station providestime slotscalle by theMSwithhelpofrepeatedradiofrequenc by BS,Msoranyotherunit.Thequal Station (MS) providesmeasurem aquickconnectiontransfer WiMAX. DuringHHO, This isacompulsorymethodofhandoverandappl 3.8.1. HardHandover(HHO)

the targetbasestationisstartedby Figure Area eserved byit.AnchorBS[28] d scanningintervalsduringwhich ents basedonwhichthedecision

3.6

of

neighbor Fast BaseStationSwitching[43] ity ofthesignalcloselylocated evious basestation

BS ons duringthistime andcanexecuteinitialranging more thanone basestationatthesame time.MS y (RF)scansdoneatregu ormed bytheMSandavalidIDforconnection requiredtodoso.NewadoptedanchorBS is formation ofthosebase d from oneanchorBStoanotherwhendesired takes placebetweentwoba ied attheinitialstage theMSwhenhandoverdecision is disconnected[28 is the only base station which for handovercanbemade either the MScarriesoutscanning.MS basestations isdetermined of handoversinmobile stations which have an stations whichhavean lar intervals.Thebase se stations.Mobile ]. ].

same carrierfrequencyisrequired. thesy FBSS andMDHOarebetterthanHHO.Forboth, copies. the downlink, employing adiversity combining tech selection diversity,theMS stations whicharebeing communicatedatuplink a This method isverymuchsimilar toFBSS.Itha 3.8.3. MacroDiversityHandover(MDHO)

chooses thebestuplinkto Figure Area

3.7

of

Macro DiversityHandover[43]

neighbor

BS s adiversity set whichconsists of allthebase nd downlinkatthe same time. Withthehelp of senddatatovariousba nique theMScombines thereceived multiple nchronization ofbasest

se stations.Whereas in ations andusageof

for thedeployment bythebackhaulregarding user toserviceproviderandpr connections incaseofmovingsubscr many otherbasestations. Itprovides roaming f Backhaul canbedefinedasahighspeedlink(mic 3.9.3. BACKHAUL coverage isconsiderablylarger. where connections tothe accesspoints areamade. WiMAX hasanedge overWiFi thatitsareaof forconnectiontoaWiMAX[44].The procedure netw Personal ComputerMobile Interface connection totheWiMAX networksismade. Itmay bea It canbereferredtoas adevicewhich receives 3.9.2. WiMAXReceiverorCustomerPremiseEquipment(CPE) are performedonrealtime basis. using MAClayerasper thestandard andensuresinteroperability of networks.All thesefunctions basestationprovidesth WiMAX directional orcangenerateevenot reality. Antennasinabasestationcangenerateci of coverageeachbase station is radius ofarea.Anywirelessdevicecanbeconnectedto Km or30Miles butdue togeographical limitations includes aWiMAX towerandelectronicdevices[23]. Base station isreferredtoasapoint from wher (BS) 3.9.1. WiMAXBaseStation considered tobeanincorporated Whereas bymeans ofbackhaulthe system isconnected b) WiMAX ReceiverorCustomer Premise Equipment (CPE). a) WiMAX BaseStation(BS). A typicalWiMAX systemisconsti 3.9 WiMAXSystemComponents ovider tothecoreWiMAX network.Anytechnology canbesupported componentoftheWiMAX system. known asacellwiththemaximu her linearshapes ofcellsin cas e frequencybandwidthtotheus tuted byfollowingtwocomponents, iber. Backhaulencapsulatesboth system connectiontothebackboneofnetwork. acility andensuresbettermobility bymaintaining e WiMAX signalsare used Card (PCMCIA)cardorastandaloneantenna rowave) whichconnectsWiMAX basestationsto the signalsfrom aBSandbyvirtueofwhich rcular cellsifthosearesupposedtobeOmni- it isin reality limited upto 10 Km or6Miles ork resembles tothatofaprocedure inWiFi The theoreticalcoverage tothecorenetwork.A internet ifitislocated e ofpointtocommunication. ers accordingtotheirdemand by m radiusof10Km or6Milesin types ofconnectionsi.e.from inthisarea.Thearea to bebroadcasted.It backhaul itselfisnot range ofaBSis50

cases likeamesh network,point-t for connectionwithinsubscriber si For idealcase,point-to-point ante communication possiblebetweendifferentbase extension intheoriginal802.16specification multipoint patternofcommuni subscribers. Schematically, WiMAX workingprinci serve thepurposeofMIMObasedwireless co IEEE 802.16specificationdefinesthe 3.10 WiMAXWorking Figure cation incellularnetworks.IEEE802.16e,which providesan nnas arereferredtoasbackhaul, must beemployed byWiMAX tes andwithbasestations which o-multipoint pattern isalsoa

working parameters forfixedandmobile WiMAX whichcan 3.8

Backhaul (WiMAX) [45] stationsunlikeIEEE802.16d(fixedWiMAX). mmunications foralargenumberofusersor for enhancedmobility, hasmade seamless ple resembles largelytothatofapoint-to- dopted toserveasabackhaul. are located distantly. In special

3.10.1 AdvancedWorkingFeaturesforWiMAX connectivity tobasestationsin ideal consideration forWiMAX point-to-multipoi base stationseitherbyemployingLOSorNLOSme Customer Premise Equipment (CPE)areprovidedw 9 9 9 9 9

frequency andupto3550 Mbpswithgreater High speedIPservices in WiMAX arecapabletoprovide 110Mbpsin3.5MHzbandof provided. OFDM PHYissupported bythearchitectureandfor NLOS operationisachievedempl The architecture isbuiltsothatitca security andencryption. The WiMAX architecture iscapable ofperfor anonlineofsightenvironment. Figure

3.9 oying robustradiointerfaces.

n eliminate PP client communication.

WIMAX working[23] nt antennas topologyissuggested forendusers numberofchannels(1420 MHz)[23]. thodology alsoknownasLa ith thepoint-to-multipoint ming coordination centra end users,facilityof connectivity by the lly withincreased st Mile[23].Inan selfinstallationis

9 9 applications which areconsidered Radio interfacewithless delays areprovided WiMAX iscapableofproviding2 nd to belatencyand jittersensitive. generation IP QoS which cansupportrealtime generationIPQoSwhich features. in WiMAX VoIPandinternetgaming like for

Access (WCDMA) respectively forbothtechnologies. Orthogonal FrequencyDivision Multiple Access(O First of allwewillcompare themultiple access 4.1 ComparisonofPhysicalLayer AccessTechniques to applications. is aimed athighlighting thepros I in detailtheprevioustwoch n thischapter we will give acomparative interpretation for the twotechnologies already discussed

COMPARATIVE Target market standardization Coverage Mobility Duplex Multiple access Band width Peak DataRate comparison Technology Table and consofboththetechnologies apters, regardingsome important

4.1 Chapter TechnologyComparison[46] Home /Enterprise 802.16 Mid Low TDD OFDM/OFDMA 5-6 GHz UL:70 Mbps DL:70 Mbps WiMAX techniques used in WiMtechniques usedin

FDMA) andWideband CodeDivisionMultiple 4

ANALYSIS DL:2 Mbps UMTS Public 3GPP Large High FDD CDMA 5MHZ UL:2 Mbps

both technically andwithrespect aspects. Thiscomparative study AX andUMTSwhichare

applications andthesecondonefo contiguous permutations forsubchannelization.Th Two typesofsubchannelpermut channel size. ad fixed frequencyspacingof10.94KHzandbythe 802.16e-2005 tosupport1.25MHz20M difference inchannelsizescountrywise.Scalab adopts S-OFDMA asmultipleaccesstechnique. Itha subcarriers tousersdependsupontheirdemands with differentdataratestousers,in subcarriers fordifferentusers.Afeaturethat is OFDMA canalsobereferred toasmulticarrier OFDMA byassigningasinglesub can besharedbymany users.Simultaneous useofth In OFDMA,the multiple access technique for WiM time andfrequencyresourcesinsubchannels[48]. symbols intime domain andsubcarriersinfre level ofcomplexityandenablesupto2048subcarri spectrums. InverseFastFourierTr efficiency isobtained bypermitting theoverla the possibilityofcrosstalkbetweensubcarriers increases thedurationofsymbols decreasesdela and division ofmain inputdatastream. Duetoreduced modulation andtransmission ofsub on OFDMmultiplexing technique. InOFDMsepa In thephysicallayerofWiMAX thetechnique a 4.1.1. OFDMAforWiMAX control, multiplexing and interface forthephysicaltransmission. Itisalso The physicallayerisconsideredto bit synchronization[47]. r fixedandportableapplications. ansform (IFFT)is used carrier oragroupofs bethemost basiclayerinane ations areusedinS-OFDMAi. streams ofinputdata Hz rangeofchannelsizes.It quency domain. Individualuser OFDMA is thatofassigningdifferentnumber is of OFDMA comparable toCDMAforassigning spreadcodes dopted forradioaccessisOFDMAwhichbased even iftheyoverlap.Henceincreasedbandwidth pping which reduces therequirement for more ility enablesthemobile WiMAX standardIEEE dataraterobustnessis responsible forfunctionslike datacoding,flow andchannelconditi ers whichisalargenumber. OFDM usesOFDM OFDMversionwithafeature of assigning ys inspreadspectrum.Orthogonalityeliminates e same channelforallusersismade possiblein AX, thechannel is divided in amanner that it s beenoptedinorder to addresstheissue of e former ismore suitable for mobile user justment of FFT according to bandwidth or justment tobandwidthor ofFFTaccording ubcarriers tothem[49]. rate orthogonal subcarriersareused for to produce OFDM signals. IFFT has lower toproduceOFDM signals.IFFThaslower withlowerdatara twork. Mainlyitprovidestheradio e. diversitypermutation and is achievedwiththehelpof ons. ThemobileWiMAX increased forOFDMasit s areallprovidedwith tes obtainedbythe

technique employedinUMTS .WCD The physicallayerofUMTS isbasedonWCDMAwhic 4.1.2. WCDMA ms Number OFDM (ms) Guard Useful (kHz) Subcarrier Channel Oversampling (Tg/Tb) Cyclic subcarriers Number Number subcarriers Number FFT Parameter

frame size

symbol symbol

prefix time

bandwidth of of

of

pilot OFDM frequency

of

null/guard assuming

rate time duration or

subcarriers

used

symbols

guard (Fs/BW)

Table (ms) (MHz)

spacing

(ms)

12.5%

4.2 band time

data

in

Different Parameters inWiMAX [51]

5

MA canbeexplaineddescribing thethreefundamental access 1.25MHz, multiples Depends 69 15.625 8 72 64 3.5 1/32 8 256 Fixed 56 192

WiMAX

of on 1.5MHz,

1.75MHz,

bandwidth:

OFDM

h isalsoreferredtoas the multiple access 2MHz,

and

or

7/6 28/25

2.75MHz.

10.94 48.0 11.4 1440 1/16 12 2048 128 OFDMA Mobile 102.9 91.4 1.25 44 72 for

for

256

multiples 60 92

WiMAX 5

1/8

OFDM, 360 512

120 184

10

of

¼

Scalable

8/7

20 240 368 1024

720

for

Frequency increased same frequency bymultiple usersatthesame tim In TDMA,Thefrequencyisdivedindifferenttime 4.1.2.2. TimeDivisionMult communication. networks. FDMAisadoptedinmost cellular subdivided forvoicetransmissionFDMA usesduplexmode of andreceptionpurposes.itimpliesthat spaceforoperation.Thisbandwidthisfurther frequency userwithaunique This providesevery In FDMA,the availablefrequency range isdivided intosmaller bandwidth andprovided to theusers. 4.1.2.1. FrequencyDivisionMultipleAccess.(FDMA) division multiplexing (CDMA) arereferred technologies: frequency division, multiplexing

oe Time Power FREQUENCY iple Access(TDMA) POWER

Figure Figure to as airinterf

4.2 4.1

(FDMA),Time division multiplexing (TDMA),Code

TDMA [50] FDMA [50] slots. Itenablestheprovisionof theusageof

e. InTDMA,thecapacityof thenetwork is TIME ace technologies.

guard bandbetweenitsneighboringcha The totalbandwidthinWCDMAis5MHzbutope downlink (fig).TDDSystem forpairband. isutilizedforunpairedbandand FDDsystem channel bandwidthwhere7channe WCDM, 12channelsarededicate In FDDmode theentireradiosp full supportforduplexcommunication sotwomodes In UMTSnetworks,powerandspreadingfactors 4.1.2.4. Description frequency band.Aof4.5to5MHzisassignedWCDMA. the transmission powertodelivertheinforma frequency domain totransmit theinformation. The For WCDMA,some upgradationswereintrodu At basestationeachuser’suniquesc CDMA eachuserhas theprovision ofusingthe w In CDMA,eachuserisassignedaspreading code fo 4.1.2.3. CodeDivisionMult • •

FDD( frequencydivisionduplex) TDD (time divisionduplex) iple Access(CDMA) ectrum wasdividedintopair d foruplinkanddownlinkFDDmode. Atotalof5MHz rambling codehelpsinitsdetection. ls arefixedforuplinkandremaining channelsareused in nnels whichreduce Figure

4.3

CDMA [50] tion through spreading inaccordance withthe hole bandwidth ofthe system forwholethetime. rating bandwidth is 3.84MHZ. There are 5 MHz rating bandwidthis3.84MHZ.Thereare5MHz are considered as avariable. WCDMA provides significant featureinWC ced inCDMA.5MHzbandwidthisused r coding anddecodingofthemassage signal. In are definedforWCDMA transmission channel. the interference

band fortherange60MHz.in

DMA isthedecreasein

be adoptedinevolut Code DivisionMultiple AccessTime Division (DS-WCDMA-FDD) isassignedfor UMTS networ Direct Sequence Wideband Code Division Multip different carriersareutilized frequency todeliverthedata.Mu Where usuallyfrequencyreusefact In thisscenario,dataisspread The othermethodisdirectsequence(DS).Where symbol rate.[4,9] hopping isalwaysgreaterthansymbol types ofmodulation whichisrepresentedasfast spreading code,carrierishoppedtoafurtherfr frequency throughadeliveredtime, wheredata Due tospreadingcodethetransmitteddatais frequency hopping(FH).Frequency hoppi WCDMA usestwobasicmethod ofspreadingina

ion of UMTS [9]. ion ofUMTS

WCDMA inagivenfrequencyband. Channel bythesupportofwholebandwid Effective Figure lti carrier(MC)spreading isan

Channel or isalwayskeptequaltoone bandwidth

4.4 ratewhileinSlowFHthera

WCDMA Frequencyband Bandwidth ng isutilized Frequency

Bandwidth

Duplex (DS-WCDMA-TDD) andMC-CDMAwill FH andslowFH.Infast equency bandinagiventime. Furtherithastwo data istransferredthroughuniquefrequencyband. varied quickly.Thevaria createsspreadbandwidth.Bysupportingthe k previouslyWhile DirectSequenceWideband given frequency band.Oneofthesemethods given frequency is le Access Duplex FrequencyDivision Duplex

3.84MHZ

in spreadspectrum to 5

MHZ

te ofhoppingissmaller thanthe other typeofspreading.Where th ofadedicatedradiochannel. . Hence,all users use similar frequencyhoppingrateof tion is duetocarrier transmit thesignal.

Original band

signal signal basedonthefollowingparameters. The productoforiginalbasebandandwideband si wideband signal.Byusingproperties, theproduct of orthogonal codeswillbezero. gets developed in accordance withthe aimofgettingtheuserdataformnoise whichisreferredto as spreading code.Bothcodesareconsideredasan or channelization). Bothcodesarecapabletoex At theend spreading codeis achieved by downlink. taken intoaccountinthedirect code intheuplinkdirection.Itis channelization codeandsecondoneisscrambling c create some limitation inradiochannel.Twotype code onlybutpracticallythereare and regardingsecurity The main whichisused factor

narrow

• • • •

Signal chip rate whichisequalto3.84million chip/sec Transmission speediscalledchiprate Chip isalsorepresented one ofcodesignal One bitbasebandsignalasassignedforpayload Wide signal

band

spreaded

Wide signal are calledcode.Basedonabovetheory

band Figure

spreaded inWCDMAcommunicationchannel ion ofuplinkwhilecellpartition is also responsibletocontrolthecha a number ofcodesthatareusedto decrease thedrawbackswhich

4.5

Spreading andDispreading [9] amine suchanoisein

multiplying thesetwotypes(scrambling and thogonal codeinsuchseries.Heretheactualidea gnals arecharacterizedasacodeinWCDMA s ofcodesareusedinWCDMA .Firstoneis ode. Physicaldataisdividedbychannelization Wide signal

band of WCDMA, there should be one ofWCDMA, thereshouldbeone

spreaded nnel. Partitionof to accessthenumber ofusers possible inthedirection of Wide signal WCDMA signal through

band

spreaded

the terminal is Received band

signal

narrow

the twotechnologies. elaborate the differenceandacomparative interpre OFDMA basedmultipath access technique [52].The following twoblock diagrams will further however, the futureevolutionofUMTSlikel Deeply analyzing,itbecomes is clearthatOFDMA follow. Now some keydistinguishingf and similarities) ofradio accesstechniques’used The abovestatedfactscleartheproceduralandope 4.1.3. Comparison(WCDMA andOFDMA) transmitted signalissame asthespreadingcode bandwidth. smaller than theentire bandwidth of WCDMA Ch WCDMA uses3.84MHzasoperatingbandwidth;the original bandwidth oftransmitted signalis signal) overtheairinterface .andfordispreading need interface. Here theoriginal narrowband signal as Figure (34)depictstheactualprocessofSpr • • • • •

OFDMA has abilitytofullys OFDMA has QoS canbeimproved inOFDMAbasedsystem OFDMA basedsystems arefreeofMultipath A OFDMA systems havebetterscal Due toOrthogonalitymaintenance theperformance bythesubchannelsinOFDMA, of system isscalabletothe bandwidthof thechannel. the entirebandwidthofchannelandforsm CDMA basedsystems havealimited supportfo is notapplicableforCDMAbasedsystems suchasWCDMA. adopted inWCDMAfo multipath users but WCDMAsystems contain channel or entirechannelbandwidthis channels areassigned tothe users inOFDMAwhereas;CDMAsystems the whole tolerant tomultipath andself interference ascompared toWCDMA. system isnotaffectedbymultipath component inOFDMA,therefore OFDMAismore

r uplinktransmission. eatures ofOFDMAandWCDMAarediscussed andcompared as upport theadvancedandsmart ability optionascompared to utilized by eachuserfortransmission. eading, dispreadingandtr ong term evolution(LTE) willalsobeadopting input ismultiplied byspreading code (wideband in both technologiesi.e. tation of thesignal transmission mechanisms for of greateradvantagesascompared toWCDMA rational detailsandcharacteristics(differences s tobemultipliedby similar spreadcode[4,9]. annel. It means theoriginal bandwidth of due tofrequencyselectiveschedulingwhich art antennatechnologies, r thistechnology,asCDMAsignalrequires ccess Interference(MAI) withreferenceto interference asasynchronousCDMA is antenna technologieswhereas WCDMA. Differentpartsof ansmission byusingaUu isUMTSandWIMAX. complexity ofthe

Receiving Bits Bits

Bits

Figure

Channel (CC coding (AWGN) Channel Bits

‐ path TC)

35

Transmitting Decoder

Block Scheme ofUMTSSignalTransmi

viterbi Decode (AWGN) Channel (Rs‐Cc) Coding Channel Receiving

Matching

path

Rate

path Estimation Channel correction

Front Front

RF RF De

‐ ‐ (Puncturing) Matching Front RF

end end

multiplexing

and

Front RF

‐

end

Interleaver ‐

end

De

Interleaver

ADC ADC Interleaver DAC DAC

Mapping De

ssion from WCDMAbasedTXtoRX[53] (QPSK) Data

Analyzer Path Interleave

De (QPSK QAM)

Mapping p Cyclic

prefix Cyclic (QPSK Mapping 64 refix 16, r

QAM)

64

coding Channelization

coding Channelization

16,

to P/S 2048) 512, FFT combiner Rake

QAM 1024, FFT

OFDM (256,

S/P to 1024,

(256, OFDM

QAM 2048)

coding Scrambling 512, coding Scrambling

better utilization ofthe radiospectrum andto a suitableandefficient modulation scheme forth different modulation schemes areadopteddependi transmit the signal successfully over long dist multiplied orassociated withasignalof higher frequency calledcarrier frequency, inorder to Modulation isdefinedasaprocedureinwhich a 4.2 ComparisonofModulation Schemes Figure

4.6

Maximum transmit

Block Scheme ofWiMAX SignalTransmi

Variable datarate

MS antennagain BS antennagain Data modulation PARAMETERS Frame duration power ofBS/Rs

bandwidth Frequency Duplexing Data rate

Coding Table

4.3

Comparison

Convolution Variable SF,Multicode Turbo andconvolution Micro cell(4W)and

Macro 17.5dBiand TDD QPSK andBPSK macro cell20W

FDD andTDD

micro 11dBi ofWCDMAandOFDM[71] WCDMA

6MHz minimize thetransmission-reception errors.Typically,

2Mbps 0.0dBi 5MHz 2GHz 10ms

ances. Inalltypesof ng onthenetworkconditions. Theemployment of e signaltransmission isof baseband signal,typically ssion fromOFDMBasedTXtoRx[53] concatenated w9threed

QAM and64-QAM 6Mbps to48Mbps BPSK, QPSK,16-

OFDMA

Solomon

100 mW

3.5GHz

0.0dBi 14dBi 20ms wireless communications,

greatusetoachieve oflowfrequencyis

this technique itisdifficult toachieve highe incorrect decision. However,the modulationrate phase. Itisconsideredasthemost robusttechni BPSK isthespecialtypeofphaseshiftkeyingte 4.2.1Binary PhaseShiftKeying(BPSK): We willdiscusssome detailsof th The followingfigurewilldemonstrate thescenario of different frequencies canbetransmitted byemployingdifferent modulation schemes inOFDM. services likevideoorvoice[54] WiMAX, anadvantageof theconceptisuninterr of adaptivemodulation enablesth referred toaslink adaptation.Incase ofmultipath fa transmission. Thisphenomenon istermed asadap with highersignal-to-noiseratio(SNR),ahigh signal tonoiseratioscenarioswhichhavelowerda transmission ofradiosignalsthatitcanadopt an edgeoverUMTS/WCDMAregardingselection 16QAM and64QAM[23]depending employed asmodulation schemes inthephysical adopted andUMTS/WCDMA andWiMAX technologi Here weshalldescribeandcompare themerits either beanalogordigital. a carriersignal isreferredtoasahighfrequency It isalsoinaccordancewithone e abovelisted modulationschemes: 01 Figure e selectionofasuitablemodula

uponthephysicalrequirements ofthenetwork.WiMAX has

4.7 r data-ratewherebandwidthislimited.

BPSK Constellations a lowlevelmodulationtec que becauseitrequiresmoredistortion toreach an chnique whichusestwophasesthatare180°outof Q sinusoidal signal.Modulationusedinthiscasecan andlimitations ofdifferentmodulation schemes is limited toonly1bit/symbol and byemploying ofadaptive modulation scheme inWiMAX. layerwhereasWiMAX employs BPSK,QPSK, 00 level modulationtechnique and applicationofam ding and othervariationsin thelinkconcept upted and thecontinues availabilityofrealtime ta ratesandincaseof tive modulation andinso I es. In UMTS/WCDMA, BPSKand QPSKare es. InUMTS/WCDMA, of the OFDM features that signalsof theOFDMfeatures tion scheme automatically. In tion scheme automatically. In odulation scheme forthe atransmission scenario hnique incaseoflower canbeadoptedfor me casesitisalso

Figure

64 –QAM 22 dB Mbps SNR =

4.8

Adaptive ModulationScheme

21.33 Q 16-QAM 10.67 Mbps PSK 5.33 Mb BPSK 2.01 Mbps

p s Base Station in WiMAX Cell[23]

SNR 16dB 6dB SNR SNR 9dB

symbols areconsideredtobesimilar. efficiency amongalltheschemes usedinWiM modulation symbol forWiMAX. 802.16 includes16-QAMwith4bitsforeachmodul of bitusedforeachsymbolthismodulation scheme varying amplitudes QAMisamong onethe schemes adoptedinWIMAX .Dependinguponnumber With thephasedifferenceof180degreeQAMuses 4.2.3. QuadratureAmplitude Modulation (QAM) not resistthenoiseaswellBPSKcan.Th compared toBPSKwithhalf the bandwidth need (constellation) whichare90degree QPSK usesfoursignalsto 4.2.2. Quadrature-PhaseShiftKeying(QPSK)

S QPSK (t)=

⎩ ⎨ ⎧ E S Cos ⎣ ⎢ ⎡ () 00 i represent fourphasesasdepi 01 −

1

64 QAMisViewedasthemodulation schemes with highest Figure s out of phase. Itcanencode2bits/symbols outofphase. whicharetwiceas π 2 ⎦ ⎥ ⎤ φ

() 4.7 t e generalequationofQPSKiswrittenas −

QPSK constellation E AX .QPSKand4-QAMwith4bitspermodulation S ed butrequires more transmitting energyandcan sin 11 10 has different types orarrays.thehas different IEEEstandard ation symbol and64QAMwith6bitfor each ⎣ ⎢ ⎡ () two differentcarrierfrequencysignalswith i − 1 π 2 ⎦ ⎥ ⎤ φ

cted from signalspacediagram () t ⎭ ⎬ ⎫ i = 1 , 2 , 3 , 4

schemes suchasbiterror rate(BER)and BPSK orQPSKwhichhavelower higherdatarateswith16-QAMa WIMAX gives we cansaythatinWIMAX higherthroughputis and datatransmitted foreachsignal. As64-QAMgivesveryhighthroughput ascompared toQPSK, efficiency andalsointhedata modulation. Moreover,thevaria modulation. However,theUMTS/WCDMAevolution UMTS/WCDMA with respecttoefficiencyand eff It canbeconcludedfromtheabovedescri

PARAMETERS WiMAX UMTS Table

4.4

16 QAM

Main Q

CC.TC RS CODING ‐ Parameters OFUMTSandWIMAX [53] IEEE802.16e CC Figure throughputs which is associated to the variation in modulation scheme throughputs whichisassociatedtothevariationinmodulation scheme

tion ispossibleinWiMAX with

4.8 data ratescomparatively.Other QPSK,16QAM,64QAM

Constellation 16QAM,64QAM QPSK I I SNR will bediscussedinchapternumberSNR will 5.

MAPPING ption thattheWiMAX hasanedgeoverthe nd 64-QAM as compared to UMTS/WCDMA with toUMTS/WCDMA nd 64-QAMascompared

achieved thanintheUMTS/WCDMA. Similarly, ectiveness byvirtue ofthefeatureadaptive i.e. HSDPA,includesth

64 QAM

Q FFT:265,512,1024,2048 Pseudo Spreading Sequence aspects relatedtothemodulation adaptive modulation inspectral SIGNAL

noise

code by

e feature ofadaptive DIVISION

I

OVSF

and

reception athigh vehicular speeds. like WCDMA andWIMAX, the InterSymbol Interfer When wetalkaboutVehicle-to 4.4 ComparisonofChannelImpairment andEqualization soft handoveristhatthedelayfo handover maintainasimultaneousconnectionwith more WiMAX makesitmore bandwidthefficientforhandoverascompare toUMTSbecausesoft supportsnetworkWiMAX technology optimized hard Generally UMTSand3GTechnologysupportsofthandoverinmobilenetworkwhereas the as atadvantageofFBSSinWiMAX [20]. anchor basestationitdoesn’t signals areprocessedonlyintheba diversity combining whileitcancommunicate withal A latesttypeofhandoverintroducedinWiMA handovers. combining forthesignals received MDHO whichissimilar infunctio and in UMTScasecalledNodeBs lying in active If MSinWIMAX andUEinUMTShavethe capabil MDHO Handovers. attain full mobility ormobili mobility atlowerspeeds isgivenbyhardhandovers UE (userequipment) incaseofUMTSislinked uptoonlyonebase station.Lowmobility or is verymuch similar forbothWiMAX andUMTS. The firsttypeofhandoveri.e.thehardis 802.16e. some featuresforusersmobility supportwereincl formobility.However notsupportandincludedanyfeatures the initialversionsofWiMAX did technologies .Originally,theUM chapters. Here weshalltake The handoverproceduresforWiMAX andUMTSha 4.3 ComparisonofHandovers ty athighspeed,theWiMAX sta employ explicitmassages forhandover -Vehicle (V2V)communicationin into accountacomparative interp r handoverisreducedinit[38]. TS technologywasintroducedfor in uplinkanddownlinkispossiblefo se stationservingastheanchorba n to that in UMTS and called n tothatinUMTSand X is FBSS which unlike MDHO do not include X isFBSSwhichunlikeMDHOdonotinclude included inboththetechnologiesanditsfunction uded inthelaterversionofWiMAX i.e.IEEE set, thetypeof hand over inWiMAX iscalled only whichcanalsobetermed asportability.To In case of WiMAX, the MS which is known as In caseofWiMAX, theMSwhichisknownas ity of communication withall the basestations, l base stations in theactive set. ForFBSSthe handovers.Asthismethod ofhandoverin ence (ISI)introduces high thanonebasestationbuttheadvantageof ve beendescribedin ndard wasprovidedwithFBSSand broadband wirelesstechnologies retation ofhandoversforboth signalling which can be viewed signalling whichcanbeviewed the mobilenetworks.Whereas se station.Incaseofchange as softerhandover.Diversity r basestation inthistype of detail inprevious level of errors in

roaming. One ofthe(CSN)responsibilities is toestabl number of taskstobe accomplished likecalladmissi security, mobility, and MS access. BTSs andNumerous ASNgateways.ASNhasseveral edge .FurtherASN,BTSandCSN responsible tomaintain thetraffi Mobile SubscriberStation (MSS)fig(4.11)Mobile service network(ASN),connectivity WiMAX mobilesystem model isconsistsof the developed itsmobile architecturetoprovide networks withrespect toitsvoice qualityan with inaradiusof4kmandis arch of3g/WiMAX).Mobile WiMAX is broadband wirelessaccess section. TheIEEE802.16isreferredtoasmob The architecturesofbothtechnologies i.e.WiM 4.5 ComparisonofArchitecture guaranteed whilemoving athighspeeds. channel exceedstheCPlength(channel).CDMAsy estimation becomes morecomplicated anddifficult capability to maintain highSNReffectively be As compared toWiMAX whichusesLMSEqua of channel[56]. maintain orthogonality,cyclicprefix(CP)in WiMAX isbasedonOFDMAtechniquetotackle receiver has theabilitytorejoincomponents Based onmultipath diversity principle WCDMA employ Rakereceiver for equalization [56] Rake channel variationdepending onthephysicalenvi temporarily (channel).WCDMAandWIMAX have adapted[55].Equalization enables In ordertominimize theeffects technologies, whichisachallenge also considered betteralternativ c throughairinterface becauseboth ar caused byISI remarkably, theme Core networkfunctionalityiscarri error freereceptionofdata are linkedupwithwholeIPcorenetwork.ASN containsmany servicenetwork(CSN), user able toprovideatle endtoservices WIMAX LMSequalizationisemployed forestimation ish alink between WiMAX a d narrow band signals .WiMAX forum hasrecently d narrowbandsignals.WiMAX forum cause inOFDMAsystems likeWiMAX thechannel AX andUMTS/WCDMA willbecompared inthis of multipath fortheimprovement ofSNR,whereas ronment conditionandalsoforbothtechnologies. following elements. Mobileuser terminal, access ile WiMAX commercially famous among the lizer, WCDMA withRakereceiver hasagreat multipath fading,inordertoreduceISIand on control,assigningtheIPaddressandbilling. stems likeWCDMA make theintegrity of data in case of higherdelayspreadwhenmultipath Host(MH)andbasest included differentmet responsibilities such asQuality of services, ast 15 Mbps data rate withfull mobility beyondairinterface. for futureofUMTS/3Gnetworks(2 e tothe fully launched UMTS/3G thod ofadaptiveequalizationis by creatingan idealchannel ed outby(CSN),where ithas a terminal applicationagentand e situated atthe same network nd 3Gnetworksthrough hod ofequalizationas ation transceiversare

with RNSthroughIuPSinterfaceand Uuinterfac is responsibletoprovidelinkwithexternalpack of twomain parts,nodeBandRNC.Corenetw contains threemain parts.UserEquipment, UT On theotherside,UMTS architectu Figure re providessupportforpacket

4.9

WiMAX Architecture [57] RAN and Core Network (CN). UTRAN is comprised iscomprised andCoreNetwork(CN).UTRAN RAN ork iscomposed ofSGSNandGGSNwhereGSSN e isable toconnect the UEandUTRAN. et switcheddatawhileSGSN iscapabletolink up lated traffic.Architecturally, it

illustrated in thefigure below. architecture andprotocol whichsupport mobility. Th The networkarchitectureworkingGroup(NWG) explains itsarchitecture. regarding serviceproviderworki three main stagesforend toendarchitectureof radio linkespeciallyonphysicalandMAClaye deployed globally.IEEE 802.16e,which WiMAX isoneoftheallIPbasedtechnologies

UE

NODE

B

RNC ng group.Stagetwoisfocusedon Figure

is most pioneeringstandard of 4.10 SGSN UMTS Integration rs. (Networking Group)WiMAX NWGhasprovided rs. (NetworkingGroup)WiMAX WiMAX .Stage oneprovidesservicerequirements WiMAX .Stage

whichfurtherbasedonOFDM.Ithasbeen GGSN of WiMAXforumhas e basic architecture ofthetwonetworks is

EXTERNAL

IP

NETWORK architecture andastagethree theWiMAX, focusesonits

designed particular

accommodate differentconfigurationaccommodate ofASN. WiMAX isconsidered toincludea simplif This multilevel mobility supportadds complexity system. GGSN level[58]in3Gcellular discussed oncomparative basis.Mobilityishandl Some basicdifferences between the networksp and multicast services. to endarchitecture ofWiMAX supportsmultimedia supportsmodularityandflexibility to WiMAX also is network architectureofWiMAX gives higheroperationalefficiencyandareduced interpreted asanallIPnetworkwithoutanyi Thenetwor between 3GPPandWiMAX networks. of thekeyfactorsdesigning At higherlevelsbotharchitecturesaresame butdiffe Figure

4.11

Network ArchitectureforUMTSandMobileWiMAX [57] architectureofWiMAX network based onpacketswitchedstructur nvolvement ofcircuittelephony.TheallIPnetwork ecifications of WiMAX andthoseof UMTSwillbe ed atintra-RNC inter-RNC,intraSGSNandinter ied andseamless mobilityfeatures which can adjust alargerangeof tonetworkarchitecture in UMTS. Whereas cost of operation with high scalability. The costofoperationwithhighscalability.The rent protocols areused atevery interface.One services, voiceover IP,andalsoIPbroadcast k architecture ofWiMAX canrightly be is toprovideinternetworking e. Thenetwork deployment [58]theend architecture of

the whole(entire)networkarea. blocking of traffic and thecoverage for cellular netw The coreobjectiveofcapacityplanning istoprovid highly dependentuponthenatureofserviceused data, UMTSservicesemploy384Kbps A datarateof64Kbpsisselected According toUMTSrelease99,thedatarateof requirement ofQoS. decreased. Thecellcapacity inWCDMA dependson is highbecausetransmission powerbecomes high capacity isalsoeffectedbydatarate(Rb).Anincreas transmitted for everyPDCHsinorderto maintain inaccordanceof WCDMA withthechangingchannel to noisespectrum densityratio) constant for access network controlthetransmit powerat each DPCH of maximum DPCHswhichcanbeassignedsimulta coverage andQoSmutually.CellcapacityinWC In WCDMA,capacity isviewed of simultaneous calls(servi can bedescribedasthemaximum ofbits amount In WCDMA, Capacityis referredto asthe capac 4.6.1 forWCDMA Here, capacityandcoverageaspectsforbothth 4.6 CapacityandCoverageComparison network architecturedonotsufferfrom su security purposeandend-to-endQualityofserv The 3G(UMTS)networkarchitecturesuffersfrom ove architecture helpsindecreas mobile WiMAX networkarchitecture and convergenceofdifferentapplicationlikeda The latency Issues are greaterfor a networkwith ces) whichacellcansupport. ing thelevel of latency in in UMTSfor circuit switched da as athreedimensional entitywhichisinterconnectedto the haslessnumber ofcontrolpoi data rate. In WCDMA systemdata rate.InWCDMA thecellcoverageisfoundtobe ch complexitiesanddifficulties[59]. having arequiredQoS[60].TheRadioaccessnetwork e technologieswillbediscussed and compared. voice serviceradiochannel that canbecommunicated and theextentofloadingcell[60]. ity of a single cell in WCDMA network.Capacity ta, voiceandvideobecome morecomplex while ice foradmission controlwhereas theWiMAX DMA network canalsobedefinedasthenumber DMA network multiple control points asinUMTS architecture neously inacellWCDMA network.Theradio signal to noiseratio(Eb/Nt)constant. The cell e thesupportforuserswithlessdelayandno orks isreferred toas th ed interference isobserved when thedatarate for highdatarateandasaresultcapacityin WiMAX networkarchitecture . mobility of channel, itsapplication types and conditions hastheabilitytoadjust power rlap infunctionalities likeauthentication for inordertomaintain Eb/Nt(energy perbit ta whereas forpacketswitched nts andasimplifieddesignof or themaximum number e mobility of servicefor is selectedas12.2Kbps.

propagation modelslike, okurama-Hata, As asecondarystepafter selec The rangeofcellorcoveragein 4.6.1.1. CoverageandCellRangeinWCDMA • •

World Cell Macro Micro Pico

Determination andcalculationoflin Calculation ofpropagationloss. WORLD CELL

Cell

CELL

cell Cell

ZONE 3 Table

ting cellrange,the coverage is Figure ZONE 4

4.5

UMTS cellcoveragecomparison 4.12

WCDMA isdetermined infollowing steps:

Walfish-ikegamiete byusingrelation.

UMTS CellStructure[61] k budgetforradiowave propagation.

ZONE 2 Un coverage 384Kbps 188Kbps 2Mbps

defined

PICO CELL

determined anyofthe byusing

QAM 5/6canbeachievedwhenusingQPSK1/2[60]. QPSK isusedwhichhaslessspectrum efficienc efficiency .ontheotherhand,foruserslocatedat stations(BTS).QAM isconsider tomostefficient range.QAM modulation isusedforthedeviceswhic depending uponthelocationofuser WiMAX holdsthecapabilityofchangingmodul also specifytheactualpoint loading. Inotherwaythecapacitymaintains thelo demand. Duetodifferent functionality theremi Emailing, Downloading,videosandfiles.However WiMAX system simultaneously facilitat system orasectorchannelcansupport. deliver. Thecapacitycanalsobedetermined byqua calculating thedatarateforeveryunitoffreq amount Cap ofdatacanbetransferredreliably? which canbecommunicatedtoandfrom theusers. For WiMAX andanyothercellularsy 4.6.2 FORWiMAX K= Constant R =Maximum CellRange(Italso S =CoverageArea The areaofcoverageforacellwithhexa S=K where load exceedstheability explainthatsectoredcells s inordertoincreaseand stem theterm capacityisreferre es allthe userstosubscribe to gonal configurationiscalculatedwhere

uency bandwidth whichthesystem cansupport to y. Only20%ofmaximum dataratethroughputof acity ofaWiMAX system canbedetermined by modulation scheme withhighervalueofspectral ght behighdatarate the system performance ischangedregardingits the systemperformance ad whendistinctusers ation techniquesautoma Forany channelalimit existsthathowmuch theedgeareasofcelloratindoorlocation, ntification ofthenumb h arelocatednearertothebasetransceiver to deliverofeverysector. arenotinhexagonalshape). improve thecoverageandits the services such asbrowsing d toasthemeasure ofdata on downloading thenup exist onasystem andit tically anddynamically ers ofuserswhichthe

. table cells intheoutdoororextendedresidentialcoverage attain andeffectiveoutdoorcoveragewithafixed The WiMAX networkarchitecturesupports thecon greater spectralefficiencycanbeachieve capacity ofWiMAX system isdependent. In Location ordistributionofusers adaptation ofmodulation types. necessarily beplacedinthearea isimprovedbytheuseofadaptivemodulaWiMAX Special considerationisgiventofrequencyreuse The datarateisarando Figure

4.13 m variablewhichdependsonuser's

Data RateofImpactModulationinWIMAX Network[62] and kindofservicewhichtheyrequirearethefactorupon with highconcentration ofusers, d usinghighconstellationmodulation. [62]. WiMAX capacitydepends uponC/Iratiobecause number useofmicro ofBTSs.The cellsandPico factor ineverychannel. tion. In WiMAX thereforeabasestationshould tion. InWiMAX withFemto-cell ispossibleasillustratedbelow cept ofmacro BTSs(mu type andmodulationtechniqueused. whichprovidesefficiencyin Thesystemcapacity in lti sector)inorder to

R =bitrateinKbps E W= refertoWCDMA chiprate T= Temperature whichisequalto290K K=Boltzmann's constantwhichisequalto 1.381 F= NoisefigureindB In aboveequationparameters represent spread spectrum whichisdefinedthroughthisequation[63] Here some estimation is given forthecapacity 4.6.3. CapacityEstimation support 7to10km infixedbroadband accessan 50kmWiMAX provide coverageforLOSand8km fo Ь requirements Site Target cost channel) MHZ capacity (10 sector Average ( Urbanarea) Range Sector

⁄ N ₀ = bitenergytonoise spectral densityindB P rss = F + KTW High High 10-15Mbps 500-1,000m Usually Macro cell + Table N E b 0 for WiMAXandWCDMA −

4.6 W R

(4.1) WiMAX DifferentCoverageRange[62]

Medium Medium 10-15 Mbps 300-500m 1-3 Micro cell d atleast200m to7km forportable [62]. ofWCDMAandWiMAX. Receiversensitivity of

Low 10-20 Mbps 150-300m 1 Pico cell Low r NLOSsituation.Buthoweverinpracticalit w ⁄ HZ ⁄ K Low 10-25 Mbps areas public enterprise, Indoor 1 Pico cell Low

Verylow 10-25Mbps residential Indoor - 1 Femto cell None

shown thegivenequation[65,66] Number ofsubchannelshowsNand N N is illustrated bythefollowing figures. needed torewrite theequation resulting there isnoshare ofto It showsthattheprocedureofsa Where SNRisthesignaltonoise In WiMAX receiver sensitivity isgivenas[64]

ғғт υ sed =192whichapplicableforallsubcarriers =256whichrepresentnumber ofsubchannel Throughput forWiMAX isgivenby

In theaboveequation’i’representsothe

T

WCDMA P r , min = P rmim = ⎣ ⎢ ⎡ 1 SNR − = BLER SNR rx + 10 rx ⎝ ⎜ ⎜ ⎛ N E + log b 10 0 ⎠ ⎟ ⎟ ⎞ 10 where W showtheuseablebandw ⎦ ⎥ ⎤ ratioandW istheeffective log tal bandwidthduringthe transmissi mpling and channelization isoccurr ( ⋅ W ⎣ ⎢ ⎢ ⎢ ⎡ 10 E ) ⎝ ⎜ ⎜ ⎛ b W + F N N s 0 N 0 16 ⎝ ⎜ ⎛ + used E R (4.2) N Fs b ⎦ ⎥ ⎥ ⎥ ⎤ N FFT r-to-own cellinterference. ForWCDMA, N ⋅ subchan = i 0 sampling frequencyFs(MHz)andsampling factor + 1 ⎝ ⎜ ⎛ ⎠ ⎟ ⎞ 8000 1 j . η Rj ⎠ ⎟ ⎟ ⎞ 800 (4.4) (4.3) . Vj nW

signal bandwidthandFis12dB ⎠ ⎟ ⎞

idth ofsubcarrierumber which ing duetobandu on ofinformation .sothereis tilization, by

supporting highthroughputandtheref technologies thatisWCDMA a It canbeconcludedfrom allth directivity of antennas, shari client forparticulartrafficload.Some factorsar particular spectrum. Ahighersyst Spectral efficiencycanbedefi 4.7 SpectralEfficiency implying AdaptiveModulationa subscriber of thebase station determines thetran WCDMA. Highdata rate transmi WiMAX' senhanceperformance agreestopresent wide spectrum. Ifwecompare WiMAX at3.5GHz its RPpropagation.Infact, WiMAX hasgreaterRF frequency. Thesebandsdonothavegoodperforman or 3.5licensedbandwherespectrum availabili WiMAX ahigh spectralefficiency provides then WC which isalready similar toUMTSrelease however itprovides37Mbpsasgoodperforma In mobile referredtoIEEE802.16e,itha WiMAX as band isbasicallyofvitalpracticalimportance inthegivenrangeof3.3to3.8GHz. If wetalkaboutWIMAX thereare2.5GHzor cell. Duetospreadspectrum itispossible toha the maximum rangeof8500bit/sandalsotherear system alargefrequencyi.e.of5MHzisspecifi Spectral efficiencies of WiMAX andUMTS/WCDMA orthogonal frequency.Spectral efficien Where G=1/ G israteofGuardperiodTg Cr representsCodingrate, T WiMAX = So E Fs f representnumber bit/symbol ofmodulation technique ⎣ ⎢ ⎡ T C G s r x isequalto15 = + E 1 T f b ⎦ ⎥ ⎤ + N N T used FFT g ng thefrequency,time distributi ned astheamountoftrafficwhichasystem transmit can fora (4.6) nd Coding(AMC)inWiMAX. nd WiMAX thatascompare toWCDMA, of WIMAX iscapable e abovediscussionregardingcapac (4.5) ssion dependsonthelocationofsu em spectralefficiencyoffers hi tothebitperiodTband ore canbeviewedasatechnol cy isoneofthekeyfactorsto 5 HSDPAwithspeedof14.4Mbps[68]. ve theminimum frequencyreusefactoras1[68]. e necessary toachieveefficientspectrum whichare ty limits the deployment of WiMAX withhigher 3.5GHz licensedspectrumselectedforit.3.5GHz ed forchannels5MHz.Eachcalliscompressed to nce.5MHz WiMAX offer withWCDMAat2.0GHz inIM2000bandthen smission dataratetobe e 100simultaneouslycallsarepossible insame ce ascompareto1.8,1.9and2GHzbanddue performance ascompared to3Gbecauseofits performance DMA. Insome scenarios,thegiven range 2.5 a feasiblesubscriber s notbeenfinalizedforitsspecificationsyet will bestudiedinthissection. InWCDMA on, environmental spacingand gh qualityofservicetotheend attainhighcellcapacity.[67] ogy withbetter ity andcoverageofthetwo bscriber. Thedistance ofthe adopted asaresultof the speedof18.7Mbps performance. Although capacitythen

there willbeapoorpropagationw operator toprovide advanced standard performanceascompared toWCDMA. (Bits/s)Hz/site System Frequency (Bit/s) Link channel(MHZ) Bandwidth Mbit/s frequency Net Standard

bit spectral

Hz

rate spectral

channel

reuse

R

efficiency

B

efficiency

factor

/frequency

R/B Table I/K

4.7

ith highfrequency.Spectraleffi

1.2 1/4 4.8 20(1.75, IEEE Spectral EfficiencyComparison [69]

802.16

3.5, WiMAX ‐ 2004

7…..)

96

5 MAX WCDMA 0.51 0.077/mobile ciency ofWiMAX also allowsthe

0.384/mobile UMTS/WCDMA

FDD

1

model willbeusedfor all the above discussedm Above istheblockdiagram ofour power andifarelationisf very small valuesofSERthesystemissaidtobe communication system. Theoverallefficiencyofth depending uponoursimulation model. There willbe acomparison oftheoreticalcalculat plot itagainst Eb/NoWhere SERisthe biterror In oursimulations, wewillcalculatetheSymbol 5.1 SimulationsUsingAWGNChannelModel comparison ofallthese modul while WCDMA usesQPSK and16-QAMastransmi I adaptive modulation isused in WiMAX. Wi n thischapter, simulation resultswillbediscusse Random Generation

bits

Figure ound betweentheseparameters thenitisofgreatimportant. SIMULATIONS ation schemes willbedone.

5.1

Modulation Simulations Model withAWGN Channel simulation modeland Chapter SERandEb/Noareveryimportant parameters in Comparison MAX utilizesBPSK,QPSK,16-QAMand64-QAM and efficient. Eb / No give information about the signal efficient. Eb/Nogiveinformation aboutthesignal Error Rate(SER)ofeachmodulation scheme and odulation schemes. Inoursimulation model, first rate whileEb/Nois the energy perbit noise. ed values of BERandsimulated values of BER

p

e systemdependsonthevaluesofSERandfor 5 ractical d. Asdiscussedintheprevious chapters that

Channel AWGN

of ssion techniques. Hereinthis chapter, a

Theoretical

it willbeimplemented inMatlab.This Results

Demodulati0n

SER arealmostthesame. Thereisonly alittledi showing thesimulated values.From thegraph,itis different valuesofEb/No.Thebluecurveis In theabove graphthetheoretical and simulated SE for thecalculation ofBERBPSKis In BPSKonebitisusedtodescribesymbol so 5.2 BPSK simulated plots. difference between our simulated resultsand theo Also agraphcontainingtheoretica demodulated andagraphbetweentheSEREb/ Gaussian Noise(AWGN)channelsothatrandomnoise and64-QAM.Aftermodulation,QPSK, 16-QAM th Then thesebitsaremodulated using differentm will takemuch more time. execution time ofourprogram isaround5minutes a represents one symbol. That’swhywearetaki schemes e.g.incaseofBPSKone symbols aremade usingthesebits.Thelengthof we generaterandombits.Inoursimulation l valuesofSERandEb/Nois bitisused torepresent one P b = 1 2 fference whenthevalueofEb/Noisnearto10dB. showing thetheoreticalva ng 1million bits.With theseonemillion bits the are generatingonemillion random bits.Afterthat odulation schemes. FirstBPSKwillbe usedthen ⎝ ⎜ ⎜ ⎛ BERisequaltotheSER.Thetheoreticalformula these symbolscanvaryindifferentmodulation clear that thetheoretical andsimulates valuesof No is plotted whichshowsthesimulatedresults. No isplotted N R ofBPSKisdepicted.SERplottedagainst E retical results. Here wewilldiscuss all our nd ifwegeneratemore bitsthentheprogram b o e signal ispassed through AdditiveWhite can beaddedtothesigna ⎠ ⎟ ⎟ ⎞

plotted to get an idea about the plotted togetanideaaboutthe symbol butinQPSKtwobits lues andpinkgraphis l. Thenthesignal is

energy /bit i.e. E=2E But QPSK system showstwo bit/symbol sotransmitted signal/symbol energyistwice thesignal equal totheSER.Thetheoretical form QPSK isalsoknownas4-QAM.Intwobits 5.3 QPSK In term of

Symbol Error Rate 10 10 10 10 10 -2 -1 -5 -4 -3

E b N -2 0 the average probabilityof Symbol error probability curve for BPSK modulation curve for BPSK errorprobability Symbol b

0

2 ula for the calculation of SERinQPSis Eb/No, dB Eb/No, P p e ≈ Figure symbol errorisequalto ≈ erfc 4 erfc

⎝ ⎜ ⎜ ⎛ 5.2 ⎝ ⎜ ⎜ ⎛ are usedtorepresentonesymbol. BERisnot

2 N E N E b 0 o 6 ⎠ ⎟ ⎟ ⎞ ⎠ ⎟ ⎟ ⎞

simulation theory 8 10

Where of SERin16-QAM is In 16-QAM,fourbitsareusedtorepresentone sy 5.4 16-QAM simulated values are thesame but This graphisshowingthetheoreticalandsimula

Symbol Error Rate 10 10 10 10 10 10 -5 -4 -3 -2 -1 0 S QPSK

-2 (t)

= M ⎩ ⎨ ⎧ 0 =

E Symbol error probability curve for QPSK(4-QAM) probability error Symbol 2 S p Cos K after12dBthereisaslight e whenKiseven ≈ 2 ⎣ ⎢ ⎡ 2 () i ⎝ ⎜ ⎛ − 1 − 1 π 2 4 1 M ⎦ ⎥ ⎤ φ Es/No, dB Es/No, () ⎠ ⎟ ⎞ Figure t erfc ted values of SERfor QPSK. Thetheoretical and − mbol. Thetheoreticalform 6 ⎝ ⎜ ⎜ ⎛

5.3 E S 2

() sin M 8 3 ⎣ ⎢ ⎡ E − differencebetween thevalues. () i av 1 − No 1 10 π 2 ⎠ ⎟ ⎟ ⎞ simulation-QPSK theory-QPSK ⎦ ⎥ ⎤

φ () t 12 ⎭ ⎬ ⎫ i = 1 ula forthecalculation , 2 14 , 3 , 4

the same. is aslight difference invalueswhen Eb/No arele In theabovefigureboththeoreticalandsimula Forpracticalpurpose M-aryQAMisgiven by

Symbol Error Rate 10 10 10 10 10 10 -5 -4 -3 -2 -1 0 0

2 Symbol error probability curve for 16-QAM modulation curve for 16-QAM errorprobability Symbol

4 p e 6 ≈ 2 ⎝ ⎜ ⎛ 1 8 − Figure Es/No, dB Es/No, 1 M 10 ted valuesofSERfor16-QAMareshown.There ss than10 dBbutafterthatthe values arealmost ⎠ ⎟ ⎞

erfc 5.4

⎝ ⎜ ⎜ ⎛ 12 N E o o ⎠ ⎟ ⎟ ⎞ 14

16 simulation theory 18 20

figure. The theoretical andsimulated valu SER in64-QAM is In 64-QAM,8bitsareused torepresent onesymbol. Thetheoreticalformula forthecalculation of 5.5 64-QAM

Symbol Error Rate 10 10 10 10 10 10 -5 -4 -3 -2 -1 0

0 Symbol error probability curve for 64-QAM modulation curve for 64-QAM probability error Symbol 5 p e es ofSERarealmost thesame ≈ 2 ⎝ ⎜ ⎛ 1 10 − 1 M Figure Es/No, dB Es/No, ⎠ ⎟ ⎞ erfc 15

5.5 ⎝ ⎜ ⎜ ⎛

2 () M 3 E − 20 av 1 No for 64-QAMasshownintheabove ⎠ ⎟ ⎟ ⎞

25 simulation theory 30

Symbol Error Rate Symbol Error Rate 10 10 10 10 10 10 10 10 10 10 10 10 -2 -1 0 -5 -4 -3 -5 -4 -3 -2 -1 0 0

0

Simulated Symbol error probability for different modulation schemes for modulation different error probability Symbol Simulated Theoatical Symbol errorprobab Symbol Theoatical 5 5 10 10 Figure Figure Eb/No, dB Eb/No, Eb/No, dB Eb/No, ility forility differentm 15 15

5.7 5.6

20 20 odulation schemes odulation 25 25 64-QAM 16-QAM QPSK BPSK 64-QAM 16-QAM QPSK BPSK 30 30

QAM. data rates when compared with 64-QAM while QPSK andBPSK haveevenless data rates than 16- Eb /Noishighthen64-QAMcanbeusedtoprovi 64-QAM hasthehighestdatarates.Whencha 16-QAM and64-QAMarelesseffici modulation schemes. QPSKisthealsoveryeffici From thegraphsitisalsovisiblethatBPSKha of theradiowavesthen thiswaveisdividedin When radiowavesstrike withan Scattering that object. compared tothewavelengthofradiowave.The This happens when radiowaves collide with theedgeof anobjectwhich hashigherlength as Diffraction object. waves thentheradiowaves come backbymaking th When radiowavescollidewithanobjectwhich Reflection received atthereceiverw refraction, diffraction and scattering phenomena’s multiple copies of thesame transmitted signal are fading is caused bythe multipath propagation of receiver soRayleighfading receiver. In most of thecellular networks there isNLOS pathbetween thetransmitter andthe transmission channelwhen we haveNon-Line of Sight(NLOS) between thetransmitter and the WCDMA incase of UMTS. Rayleigh fading in norma transmission model, thereisaneedofusing Rayleigh fadingchannelfortransmission.Byth In thepreviousmodel, wasusedfo AWGNchannel 5.6 SimulationsusingRayleighFadingChannelModel modulation schemes arealmost thesame. Thisshow schemes. Form theabovefiguresitisclearthat The abovetwofiguresshowtheth waves. Allthesephenomena’s ar ith different time intervals. is essential in allthesenetworks. As e showninthefigurebelow. object thathassame orlesslengt eoretical andsimulated results ent in terms ofSERwhencomp OFDM asatransmission techniqueinWiMAX and to alldirectionbymaking e introductionofRayleigh nnels conditionsareverygoodmeans thevalueof s theleast SERwhencompared toalltheother ent butithashigherSERascomparedtoBPSK. has higherlengththenth the theoreticalandsimulated resultsforallthe s thatthesimulation mode de highdatarates.16- radio wavesinfreespace.Duetoreflection, radio waves bendsafterstrikingtotheedgeof r transmission. Inthisnew model we will use e same angleatwhich theycollidedwith the lly caused bythemultipath interference in the it is discussed earlier thatRayleigh h as compared to thewavelength for allofthefour modulation ared toQPSKandBPSK.But QAM hasrelatively less e wavelengthsofradio different weakerradio fading channelinour l isquiteefficient.

just bendbymaking some when theytravelfrom airandenter inwater,there This phenomena occurswhenradiowavesenterfr Refraction Figure angleofincident. Figure

5.8 :

Reflection, DiffractionandScattering [72]

5.9 : Refraction[72] is aslightchangein th om onemedium toanothermedium. Forexample

e propagationpathandthey

comparison between our theoretical andpractical results. the receivedsignalismodulated and using OFDM.Afterthatthesebitsarepassedth used asatransmission medium. Firstrandom bitsar belo Our newsimulationmodelisshowninthefigure transmission technique. as thereceiver isunabletoidentify theoriginal signal. To overcome thisproblem OFDM isusedasa time ofarrival.Thesedifferent signals arecausing multiple bits arethereforasingle bit.Thesebits different time intervals. Thismake verydifficult multiple copies ofthesame signalarearriving atth In theabovefiguremultipath propagationofradiowa

Figure

5.10 Multipath Propagation of radio waves. [73] the originalsignalis rough aRayleighfadingchanne for thereceivertorecogni are different from eachotherdue to theirdifferent Inter Symbol Interference (IS e receiver. Thesecopies come receiver atthe on e generated,andthenth ves isshown.Itclearfromthefigurethat w. Inthismodel, Rayleighfadingchannelis recoveredfrom itandthen we perform a ze theoriginalsignalas eses bitsaremodulated l. Atthereceiverend I) atthereceiverend

Random bits

Theoritical Value of SER 10 10 10 10 10 -4 -3 -2 -1 0 Figure 0

OFDM 5.11 5

Comparison of Theoretical Theoretical of Comparison

Simulation ModelwithRayleighFadingChannel Figure and practical Results and practical

10

5.12 15

theoretical 20 SNR dB SNR Rayleigh Channel

25 Fading value

of

30

SER

in 35

OFDM 40

64QAM Mod 64QAM Mod 16QAM QPSK Mod BPSK Mod

Demodulation 45

50

of SNRwithothermodulation techniques. ProbabilityoferrorforMaryQAMha In M-arypskprobabilityoferrorca in figure5.13,weobserved that fading wearehavinghighvaluesofSERagainst SNR. Rayleigh fadingchannelandOFDMar In theabove figures,theoratical valuesof P p e ≈ e ≈ 2 ⎝ ⎜ ⎜ ⎛ erfc 1 − ⎝ ⎜ ⎜ ⎛ 1 M N E

⎠ ⎟ ⎟ ⎞ Probability of Error erfc S O 10 10 10 10 10 i sin 0 -4 -3 -2 -1 0

⎝ ⎜ ⎜ ⎛ ⎝ ⎜ ⎛ M π 2 () M ⎠ ⎟ ⎞ ⎠ ⎟ ⎟ ⎞ 3 − E Figure 1 5 S N BPSK ismost efficientto achieve

n calculate by usingthis formula. O 5.13 ⎠ ⎟ ⎟ ⎞ s beencalculatedbyfollowingformula. e depicted.From thegraphitis

probability 10 SER forBPSK,QPSK,16QAMand64QAM by using SNR dB

of 15

error Thisisduetothemultipath interfernce. And

in

term 20

of

SNR same probaility of error in term

64QAM Mod 64QAM Mod 16QAM Mod QPSK ModBPSK 25 clearthatbyusingRalyeigh 30

service, scalability,higher carrier andmulticarrier opera The WiMAX technologyencirclessome dominating support, WiMAX isbecoming With extendedbroadbandcapability WiMAX wasaimed atcomplementing the3G networks the voicebutafterwards,itwasupgradedtoinclude (3G). Initiallythe3GandUMTSnetworkswere atendencytobecomeWiMAX has acomplement the twocanbedeclaredcomple robustness andphysicallayerparame features ofboththet of WiMAX whichdeploysfeatures of WiMAX isconsideredtobehighlyrobustand advance securityfeaturesarealsothehighlightin T 6.1 Conclusions architecture itprovides and stringencryption.Techniquesprovidebetter secur of QoSsupport.Moreeverit’s provides supportforpowersavingoper includes strongandaveryeffec sub channelizationandmultiuserdiversityaream performance asitemploys OFDMAasmultiple acce (IFFT) whichhelpsincoopingwithmultipath effect support pagingforthebase station of thefeaturesreference m as UMTSandotherCDMAsystems inthefield here exists an environment of hard competition between WiMAX and3Gcellular systems such

support foritshandlingmodelsuchasfi echnologies includingarchitecture, supportfor mobility, veryflexiblear CONCLUSIONS odel isprovidinginteroperability a greatthreattoUMTS. tely suppressingtheother. tion, WiMAX cansupportbothFDD tion, WiMAX PDU construction,ARQmechanis tive errorcodinginthePhysical and alsoinactivemode operation. likecyclicprefix(CP)and Chapter , distance servicecapability ters indetail,wecanconclude ation and itsarchitecture has th g featuresofWiMAX tec flexible. OFDM is employed inthephysicallayer flexible. OFDMisemployed ong distinguishing featuresofOFDMA.WiMAX

ary wirelessboardbandtechnologytoUMTS andreducingISI.MobileWiMAX givesbetter 6 datatransmission capabilityaswell.Whereas designedasanetworkforthetransmission of ss technique. Adaptivemodulation andcoding, of mobile broadband.Af features ofadvantageoverUMTS.Forsingle ity in userdatatransmission. Duetoflexible

withcapabilityofhi

radio accesstechniques,mobility, between thenetworks.The network xed, mobile andalsonomadic. One chitecture withhi Layer.MACLayerofWiMAX and aneffectiveQoSforvoice m andpowerfullauthentication Inverse Fast Fourier Transform Inverse FastFourierTransform thatnotasingletechnologyof and TDD.Advancequalityof e capabilityfordifferenttypes

hnology. Theairinterface gh speeddataservices. ter discussingvarious gh datarateand

internet forallusers any time andat higher bandwidth.WiMAX issoonexpectedtoprovi LOS andNLOSdatatransmission aresupportedin flaws cellularnetworkslikeUMTS.Ithasbeenf offering betterservicesthenUMTS It canbe observed bycompari with AccessContro In futurearchitecturecanbeproposedforthein 6.2 FutureWork size. Itisalso expectedtoincludeafastcells like adoptivemodulation andcoding,HybridAutoma rates andwork isinprogressoverHighSpeed effective IP support.However,theupcoming 3GPPre and allIPcorebasednetworkisprovided by employing ATMtechnology.IntheWCDMA isunde Access) forsignalspreading.UMTS employs QPSKPasmodulation techniqueandDSCD discuss UMTSwhichemploys WC Here wewill mobility scheme isneededinfuture regarding multiple operator environments. provided withlowerhandoverlatenc mobile broadbandusercanbef switching between thenetworks i.e. lowpacket lo arch affectively. UMTSandWiMAX interworking andhandoversfromUTRAN (UTMS) UTRAN management, seamless handoverprocedurei.e. handoverfrom accessnetworkof WiMAX to standard. Thesocalledinternetworkingmodel should The saidinternetworking architecture forUM becomes possibletothe differen UMTS employing IPasacommon interconnection l Channel(ACCH). ng WiMAX and UMTS features that ng WiMAX andUMTSfeatures t networks(internetworking). acilitated if the proper 3GPP WiMAX acilitated iftheproper3GPP . Itprovided solutionforsome ofthetechnical complexity and any placeinstaticandmoving position. y andreducedpacketloss.Aroam is capableofofferingpacketsw side selection mechanism in specificationsof TS andWiMAX maypossi Packet Access(HSPA)whichmay include feature terworking oftheboth

DMA asradioaccesstechnology,whichmainly WiMAX withincreasedsecuritymechanism and ound more spectrallyeffere itecture shouldpromised reducedlossesdueto ss andreducedtime ofinterruption.Infuture tic RepeatRequest(HARQ),andreducedfrom to WiMAXaccessnetwork efficiently and MA (Direct Sequence CodeDivision Multiple protocol theseamless connectionofmobiles de thefacilityofhi address theissuesofarchitecture,IP leases aresupposedto r goingaprocessofevolutionatthetime WCDMA RELEASE2000with generallyWIMAXiscapable itch andcircuit ing architectureandefficient ing and uplink DCH Associated and uplinkDCHAssociated interworking architectureis interworking technologies. WIMAX and gh speedconnectivityto ble isbasedon3GPP providehigherdata nt andflexible.both switch services

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,

PDA Personal LOS Line SOFDMA Digital OFDMA of Orthogonal Assistant IP Internet Protocol Sight Frequency MAC OrthogonalFrequency Division Multiplexing Division 3G Media 2G SecondGeneration Multiple Access Third OFDM Access Control SMS Generations Short GPRS EnhancedDataratesforGSM Evolution EDGE General Messaging AMPS Packet Wireless LocalAreaNetwork Services NMT Advance radio QoS Nordic Mobile Quality Service WLAN Mobile Phone UMTS of Telecommunication GSM Systems Universal Service System RRM Global Mobile WiMAX Radio System Telecommunication Resource for Worldwide System Management Mobile Interope Communication

Abbreviations ScalableOrthogonalFre APPENDIX

rability forMicrowave Access and quency DivisionMultiple Access

A

Acronyms

CM Wideband Code Division Multiple Access WCDMA ITU International PSTN DSL Telecommunication Public Digital MSC Union switched Master BSC Subscriber Telecommunication Base DHCP Switching Line Networks CSN Station Dynamic Center Connection SNR Controller Host Signal CRC Service Control Cyclic ARQ to Network Automatic FEC Protocol Redundancy Noise Forward SFID Repeat Check Ratio BS Service Error Request Base MS Flow Correction Mobile Station CID Identifier Connection Station DOCSIS PHY Identifier Physical TDM ATM Time Layer MPDU Asynchronous Division FFT Transfer MAC Multiplexing Fast ISI Inter Mode Protocol FDD Fourier Symbol Data Frequency TDD Transform Time Interference Units Division Division Duplex Duplex DataoverCableServiceInterface Specification

TA UniversalTerrestrial RadioAccessNetwork UTRAN USIM CN UMTS Core IFFT Subscriber Network Inverse EVDO Identity HSPA Fast Evolution-Data Compartmentalization of DecayinTrees Module LTE High Fourier Optimized Long HSUPA High-Speed Speed Transform Term HSPDA High-Speed Uplink Packet CODIT Evolution Downlink Packet Access ITU-TS Telecommunication ExtendedAccessCommunicationSystem Packet Access RAN Union-Telecom Access Radio VOIP Sector ETSI Voice Access European ETACS over Network MultipleInput Output TACS Telecommunication Internet CPE BinaryPhaseShiftkeying Total Standard Protocol Customer MIMO Access Institute QAM Premises Communication QPSK Quadrature Equipment Time DivisionMultiple Access BPSK System Quadrature Amplitude FDMA Phase Modulation TDMA Frequency Shift CDMA Code Division keying Division Multiple Multiple Access Access

HC SharedChannel ControlChannel DDC Dedicated DTCH SHCCH Transport Dedicated DCCH Channel Traffic CCCH Dedicated Channel PCCH Common Control BCCH Control Channel RNC Broad Paging Channel Radio RNSs Cast Control GMSC Radio Network Control Channel AUC Network Gate Controller Channel Authentication HLR Subsystem Way Home FBSS Center Mobile GGSN Fast Location Switching SGSN Gateway Base Register VLR Center Service GPRS Station Visitor HLC GPRS Support Switching Home CRNC Location Support Node RNSs Location Controlling Register Node Home IU Radio Center Network RNC Interface TN Network Transit Unit SN Subsystem Service Network HN Network

TDM Wireless Metropolitan Area Networking Time FEC Forward DSL Division Digital Error BWA Multiplexing WMAN Broadband Subscriber Correction RAM Wireless Line Radio RAT Access Radio TDD Access Time FDD Access Mode Frequency TFDivision Technique NLOS Division Duplex BLER Non Duplex TransportMRC Block Line Maximum HCS Error Of Hierarchal DS Ratio Rate Direct Sight FH Cell Combining Frequency Spread CPCH Structure Hopping DSCH RACH Downlink Uplink PCH Random Shared Common Paging FACH Access Channel Packet BCH Channel Forward Channel Broadcast CTCH Channel Access Channel Common Channel FormatTraffic Channel

H-ARQ H-ARQ Extensible Authentication FBSS Protocol AMC Fast Adaptive WLANBase EAP Modulation Station and Switching Coding Wireless Local Area Network NWG Networking MA Mobile Group MH Agent MSS Mobile CP V2V Subscriber Mobile Vehicle-to 64QAM 64Quadrature Station DirectSequence Wideba Cyclic 16QAM Vehicle 16Quadrature Amplitude DirectSequence Wideba DSWCDMA-TDD Amplitude Modulation DS-WCDMA-FDD Modulation MC SLA Service NAP Network RRC Level MediaHost Radio MS Access Agreement Mobile ASN Resource Provider Prefix Station Access NRM Management Network MDHO Macro Service Reference Diversity Network Model Handover Center yrdAtmtcRpa eus Hybrid Automatic RepeatRequest nd CodeDivisionMultiple Access TDD nd CodeDivisionMultipleAccessFDD

PersonalComputer MemoryCard PCMCIA SRNC ATM Serving SER RNC Symbol Asynchronous Error Transmission Rate Mode

for ii=1:length(Eb_N0_dB) Eb_N0_dB =[-3:10];% multiple Eb/N0 values n =1/sqrt(2)*[randn(1,N)+j*randn(1,N)]; s =2*ip-1;%BPSK ip =rand(1,N)>0.5;%generati % Transmitter randn('state',200); %initializing therandn()function rand('state',100); %init N =10^6;%number ofbitsorsymbols close all clear all forBPSK % Code %------% M.UmairAslamemail:[email protected] % Salahuddinemail:sa % ArifHussainemail:[email protected] % thiscodeiswritten by %------

------ializing therand()function modulation 0->-1;1 ->0 [email protected] Matlab ng 0,1withequalprobability ------APPENDIX

%whitegaussiannoise,0dBvariance Simulation ------

B ------% ------%

code

for ii=1:length(Es_N0_dB) ipHat =zeros(1,N); Es_N0_dB =[-3:20];%multiple Eb/N0 values N =10^5;%number ofsymbols %code forQPSK title('Symbol errorprobability ylabel('Symbol ErrorRate'); xlabel('Eb/No, dB'); legend('theory', 'simulation'); grid on axis([-3 1010^-50.5]) semilogy(Eb_N0_dB,simBer,'mx-'); hold on semilogy(Eb_N0_dB,theoryBer,'b.-'); figure; theoryBer =0.5*erfc(sqrt(10.^(E simBer = nErr/N;%simulated ber end nErr(ii) =size(find([ip-ipHat]),2); % countingtheerrors ipHat=real(y)>0; %receiver-harddecisiondecoding y=s+10^(-Eb_N0_dB(ii)/20)*n; %Noiseaddition curve for BPSK modulation'); curve forBPSK b_N0_dB/10))); %theoreticalber % additivewhitegaussiannoise

xlabel('Es/No, dB') legend('theory-QPSK', 'simulation-QPSK'); grid on axis([-3 1510^-51]) semilogy(Es_N0_dB,simSer_QPSK,'mx-'); hold on semilogy(Es_N0_dB,theorySer_QPSK,'b.-'); figure close all (1/4)*(erfc(sqrt(0.5*(10. theorySer_QPSK =erfc(sqrt(0.5*(10.^(Es_N0_dB/10)))) - simSer_QPSK =nErr/N; end nErr(ii) =size(find([ip-ipHat]),2) ipHat(find(y_re >=0&y_im <0))=1-1*j; ipHat(find(y_re <0&y_im >=0))=-1+1*j; ipHat(find(y_re >=0&y_im >0))=1+1*j; ipHat(find(y_re <0&y_im <0))=-1+-1*j; y_im %imaginary =imag(y); y_re =real(y); %real % demodulation y =s+10^(-Es_N0_dB(ii)/20)*n;% n =1/sqrt(2)*[randn(1,N)+j*randn(1,N) s =(1/sqrt(2))*ip; %normalization of energy to1 ip =(2*(rand(1,N)>0.5)-1)+j*(2*(rand(1,N)>0.5)-1);% ^(Es_N0_dB/10))))).^2; ; %coutingthe number oferrors additive whitegaussiannoise ]; %whiteguassiannoise,0dBvariance

ipHat_im(find(y_im< -2/sqrt(10))) =-3; ipHat_re(find(y_re>0&y_r ipHat_re(find(y_re>-2/s ipHat_re(find(y_re>2/sqrt( ipHat_re(find(y_re<-2/sqrt( y_im =imag(y); %imaginary part y_re=real(y);%realpart %demodulation y=s+10^(-Es_N0_dB(ii)/20)*n n=1/sqrt(2)*[randn(1,N)+j*randn( s=(1/sqrt(10))*ip; % ip=randsrc(1,N,alpha16qam) +j*randsrc(1,N,alpha16qam); for ii=1:length(Es_N0_dB) ipHat =zeros(1,N); Es_N0_dB =[0:20];%multipleEs/N0values alpha16qam =[-3-113];%16-QAMalphabets N =10^6;%number ofsymbols clear % 16-QAMmodulation title('Symbol error probabili ylabel('Symbol ErrorRate') normalization ofenergyto1 qrt(10) &y_re<=0))=-1; ty curve forQPSK(4-QAM)') e<=2/sqrt(10))) =1; 10))) =3; 10))) =-3; ; %additivewhitegaussiannoise 1,N)]; %whiteguassiannoise,0dBvariance

M =64;%number ofconstellation points N =10^3;%number ofsymbols close all clear all % 64-QAMmodulation title('Symbol errorprobability ylabel('Symbol ErrorRate') xlabel('Es/No, dB') legend('theory', 'simulation'); grid on axis([0 2010^-51]) semilogy(Es_N0_dB,simBer,'mx-','Linewidth',2); hold on semilogy(Es_N0_dB,theoryBer,'b.-','LineWidth',2); figure close all theoryBer =3/2*erfc(sqrt(0 simBer =nErr/N; end nErr(ii)=size(find([ip- ipHat] ipHat=ipHat_re +j*ipHat_im; ipHat_im(find(y_im>0 &y_im<=2/sqrt(10))) =1; ipHat_im(find(y_im>-2/sqrt(10) &y_im<=0)) =-1; ipHat_im(find(y_im >2/sqrt(10)))=3; .1*(10.^(Es_N0_dB/10)))); curvefor16-QAMmodulation') ),2); %coutingthe number oferrors

%4to6-->5etc %2to4-->3 %0to2-->1 %roundingtothenearestalphabet ipHat_re(find(ipHat_remax(alphaMqam))) =max(alphaMqam); ipHat_re=2*floor(y_re/2)+1; %4to6-->5etc %2to4-->3 %0to2-->1 %roundingtothenearestalphabet y_im =imag(y)/k; %imaginary part y_re=real(y)/k; %real part % demodulation y =s+10^(-Es_N0_dB(ii)/20)*n;% n=1/sqrt(2)*[randn(1,N)+j*randn(1, s=k*ip;%normalization ofenergyto1 ip=randsrc(1,N,alphaMqam) +j*randsrc(1,N,alphaMqam); for ii=1:length(Es_N0_dB) ipHat =zeros(1,N); %init Es_N0_dB =[0:30];%multipleEs/N0values alphaMqam =[-(2*m-1) 2*m-1]; m =[1:sqrt(M)/2]; %alphabets k =sqrt(1/((2/3)*(M-1))); %normalizing factor additive whitegaussiannoise N)]; %whiteguassiannoise,0dBvariance

close all clear all % CodeforBPSK %simulted andtheoratical sym title('Symbol errorprobability ylabel('Symbol ErrorRate') xlabel('Es/No, dB') legend('theory', 'simulation'); grid on axis([0 3010^-51]) semilogy(Es_N0_dB,simSer,'m*-','Linewidth',1); hold on semilogy(Es_N0_dB,theorySer,'bs-','LineWidth',2); figure close all -(1-2/sqrt(M) +1/M)*(erfc( theorySer =2*(1-1/sqrt(M))*erfc simSer =nErr/N; end nErr(ii)=size(find([ip- ipHat] ipHat=ipHat_re +j*ipHat_im; ipHat_im(find(ipHat_immax(alphaMqam))) =max(alphaMqam); ipHat_im =2*floor(y_im/2)+1; k*sqrt((10.^(Es_N0_dB/10))))).^2; curvefor64-QAMmodulation') bol errorrateprobabilityfo ),2); %countingthenumber oferrors (k*sqrt((10.^(Es_N0_dB/10)))) ... r diffrentmodulation scheme

% axis([-31010^-50.5]) % semilogy(Eb_N0_dB,simBer,'mx-'); % holdon % semilogy(Eb_N0_dB,theoryBer,'b.-'); % figure; theorySer1 =0.5*erfc(sqrt(10.^(Es_N0_dB1/10))); %theoretical ber simSer1 =nErr1/N;%simulatedber end nErr1(ii)= size( %countingtheerrors ipHat=real(y)>0; %receiver-harddecisiondecoding y=s+10^(-Es_N0_dB1(ii)/20)*n; %additive whitegaussian noise %Noiseaddition for ii=1:length(Es_N0_dB1) Es_N0_dB1 =[-3:10];%multiple Eb/N0values n =1/sqrt(2)*[randn(1,N)+j*randn(1,N)]; s =2*ip-1;%BPSK ip =rand(1,N)>0.5;%generati % Transmitter randn('state',200); %initializingtherandn()function rand('state',100); %init N =10^6;%number ofbitsorsymbols clc find([ip- ipHat]),2); ializing therand()function modulation 0->-1;1 ng 0,1withequalprobability %whitegaussiannoise,0dBvariance

simSer_QPSK =nErr2/N; end nErr2(ii) =size(find([ip- ipHat]),2) ipHat(find(y_re >=0&y_im <0))=1-1*j; ipHat(find(y_re <0&y_im >=0))=-1+1*j; ipHat(find(y_re >=0&y_im >0))=1+1*j; ipHat(find(y_re <0&y_im <0))=-1+-1*j; y_im %imaginary =imag(y); y_re =real(y); %real % demodulation y =s+10^(-Es_N0_dB2(ii)/20)*n; n =1/sqrt(2)*[randn(1,N)+j*randn(1,N) s =(1/sqrt(2))*ip; %normalization of energyto1 ip =(2*(rand(1,N)>0.5)-1)+j*(2*(rand(1,N)>0.5)-1);% for ii=1:length(Es_N0_dB2) ipHat =zeros(1,N); Es_N0_dB2 =[-3:20];%multiple Eb/N0values % N=10^5;number ofsymbols % QPSK % title('Symbol error % ylabel('Symbol ErrorRate'); % xlabel('Eb/No, dB'); % legend('theory', 'simulation'); % gridon probability curvefor ; %coutingthenumber oferrors % additivewhitegaussiannoise ]; %whiteguassiannoise,0dBvariance BPSK modulation');

y_im %imaginary =imag(y); part y_re=real(y); %real part % demodulation y=s+10^(-Es_N0_dB3(ii)/20)*n; n=1/sqrt(2)*[randn(1,N)+j*randn(1, s=(1/sqrt(10))*ip; % normalization of energyto 1 ip=randsrc(1,N,alpha16qam) for ii=1:length(Es_N0_dB3) ipHat =zeros(1,N); Es_N0_dB3 =[0:20];%multiple Es/N0 values alpha16qam =[-3-113];%16-QAMalphabets % N=2*10^5;number ofsymbols % 16-QAMmodulation % title('Symbol error probabil % ylabel('Symbol ErrorRate') % xlabel('Es/No, dB') % legend('theory-QPSK', % gridon % axis([-31510^-51]) % semilogy(Es_N0_dB,simSer_QPSK,'mx-'); % holdon % semilogy(Es_N0_dB,theorySer_QPSK,'b.-'); % figure; (1/4)*(erfc(sqrt(0.5*(10. theorySer_QPSK =erfc(sqrt(0.5*(10.^(Es_N0_dB2/10))))- ^(Es_N0_dB2/10))))).^2; 'simulation-QPSK'); ity curve forQPSK(4-QAM)') +j*randsrc(1,N,alpha16qam); % additivewhitegaussiannoise N)]; %whiteguassiannoise,0dBvariance

% N=7*10^5;number ofsymbols % 64-QAMmodulation % title('Symbol error % ylabel('Symbol ErrorRate') % xlabel('Es/No, dB') % legend('theory', 'simulation'); % gridon % axis([02010^-51]) % semilogy(Es_N0_dB,simBer,'mx-','Linewidth',2); % holdon % semilogy(Es_N0_dB,theoryBer,'b.-','LineWidth',2); % figure; theorySer3 =3/2*erfc(sqrt simSer3 =nErr3/N; end nErr3(ii)=size(find([ip- ipHa ipHat=ipHat_re +j*ipHat_im; ipHat_im(find(y_im>0 &y_im<=2/sqrt(10))) =1; ipHat_im(find(y_im>-2/sqrt(10) &y_im<=0)) =-1; ipHat_im(find(y_im >2/sqrt(10)))=3; ipHat_im(find(y_im< -2/sqrt(10)))=-3; ipHat_re(find(y_re>0&y_r ipHat_re(find(y_re>-2/sqrt(10) &y_re<=0)) =-1; ipHat_re(find(y_re>2/sqrt(10))) =3; ipHat_re(find(y_re< -2/sqrt(10))) =-3; probability curvefor16-QAMmodulation') (0.1*(10.^(Es_N0_dB3/10)))); e<=2/sqrt(10))) =1; t]),2); %couting thenumber of errors

%2to4-->3 %0to2-->1 %roundingtothenearestalphabet ipHat_re(find(ipHat_remax(alphaMqam))) =max(alphaMqam); ipHat_re=2*floor(y_re/2)+1; %4to6-->5etc %2to4-->3 %0to2-->1 %roundingtothenearestalphabet y_im =imag(y)/k; %imaginary part y_re=real(y)/k;%realpart %demodulation y=s+10^(-Es_N0_dB4(ii)/20)*n; n=1/sqrt(2)*[randn(1,N)+j*randn( s=k*ip;%normalization ofenergyto1 ip=randsrc(1,N,alphaMqam) +j*randsrc(1,N,alphaMqam); for ii=1:length(Es_N0_dB4) ipHat =zeros(1,N); %init Es_N0_dB4 =[0:30];%multiple Es/N0 values alphaMqam =[-(2*m-1) 2*m-1]; m =[1:sqrt(M)/2]; %alphabets k =sqrt(1/((2/3)*(M-1))); %normalizing factor M =64;%number ofconstellationpoints % additivewhitegaussiannoise 1,N)]; %whiteguassiannoise,0dBvariance

semilogy(Es_N0_dB4,theorySer4,'k+-','LineWidth',1.5); hold on semilogy(Es_N0_dB3,theorySer3,'b+-','LineWidth',1.5); hold on semilogy(Es_N0_dB2,theorySer_QPSK,'g+-','LineWidth',1.5); hold on title('Theoatical Symbol errorprobabili ylabel('Symbol Error Rate') xlabel('Eb/No, dB') grid on axis([0 3010^-51]) semilogy(Es_N0_dB1,theorySer1,'r+-','LineWidth',1.5); figure; % theoratical -(1-2/sqrt(M) + 1/M)*(erfc(k*s theorySer4 =2*(1-1/sqrt(M))*erf simSer4 =nErr4/N; end nErr4(ii)=size(find([ip- ipHa ipHat=ipHat_re+j*ipHat_im; ipHat_im(find(ipHat_immax(alphaMqam))) =max(alphaMqam); ipHat_im =2*floor(y_im/2)+1; %4to6-->5etc qrt((10.^(Es_N0_dB4/10))))).^2; t]),2); %countingthenumber oferrors c(k*sqrt((10.^(Es_N0_dB4/10)))) ... ty fordifferentmodulation schemes')

% trellis=poly2trellis(7,[171 133]); X1 =rand(1,N_of_sub)>0.5; % InputData N_of_sub =1000; % No.ofSubcarriers clc clear all close all % simulationcodefordifferentmodulation legend('BPSK','QPSK','16-QAM','64-QAM'); semilogy(Es_N0_dB4,simSer4,'k+-','LineWidth',1.5); hold on semilogy(Es_N0_dB3,simSer3,'b+-','LineWidth',1.5); hold on semilogy(Es_N0_dB2,simSer_QPSK,'g+-','LineWidth',1.5); hold on title('Simulated Symbol errorprobabili ylabel('Symbol ErrorRate') xlabel('Eb/No, dB') grid on axis([0 3010^-51]) semilogy(Es_N0_dB1,simSer1,'r+-','LineWidth',1.5); figure; % simulated legend('BPSK','QPSK','16-QAM','64-QAM'); ty fordifferentmodulation schemes') scheme with Rayleighfadingchannel

% RayleighFadingChannel awgn(out,100,'measured');y_AWGN = % Transmit signalthroughanAWGN channel. out =reshape(cyc_pr(co % ParalleltoSerial len_cyc_pr =length(cyc_pr); cyc_pr(count1,:) =cyclicpa % AddCyclicPrefix ifft_y_mod =ifft(y_mod); % ApplyIFFT operation end y_mod=modulate(modem.qammod(alphabet_M),par); else y_mod=modulate(modem.pskmod(alphabet_M),par); if(alphabet_M<=8) % UseM-arymodulation topr alphabet_M =+X2; for count1=2:1:6; X2 =0; alphabet_M =2;%Alphabetsize % M-aryPSKModulation par =series2parallel(X1,N_of_sub); % SerialtoParallelCo % code=convenc(x,trellis); nversion ofInputdata unt1,:),1,len_cyc_pr); d(ifft_y_mod,256); %#ok % Encodeastringofones. oduce modulated signaly_mod.

error=0; if (xdash(:,a) ==X1(:,a)) for a=1:1:N_of_sub; error =0; xdash =reshape(fft_y_mod,1,N_of_sub); % ParalleltoSerial end y_demod=demodulate(modem.qamdemod(alphabet_M),fft_y_mod); else y_demod=demodulate(modem.pskdemod(alphabet_M),fft_y_mod); if (alphabet_M<=8) % Demodulate fftsignalatRxer. fft_y_mod fft(r_cyc_pr(count1,:)); = % FFT len_rcp =length(r_cyc_pr); r_cyc_pr(count1,:) =decyclicpad(par2,256); % Remove cyclicprefix re_par =real(par2); par2 =series2parall % SerialtoParallel R_fading_ch %Displayallpropertiesofthechannelobject. rf =filter(R_fading_ch,y_AWGN); %Passsignal through channel. R_fading_ch =rayleighchan(1/1000,100,[02e-5],[0-9]); el(rf,len_cyc_pr);

ylabel('Symbol ErrorProbability') xlabel('SNR dB') grid on axis([0 250.000011]); semilogy(EbNo,S_err(2,:),'+c',EbNo,S_err(3,:),'-b' figure() %decoded =vitdec(xdash,trellis,tb,'trunc','soft',128); %tb =2;%Tracebacklengthfordecoding end alphabet_M= 2^count1; end Pr_err(count1,:)=2*((1 SERtheory(count1,:)=berf S_err(count1,:) =bera else Pr_err(count1,:)=erfc(s SERtheory(count1,:)=berf S_err(count1,:) =berawgn( if(alphabet_M<=8) EbNo =0:1:N_of_sub-1; terror(count1,:) =error; end end error=error+1; else wgn(0.9*EbNo,'qam',alphabet_M); -(1/sqrt(alphabet_M)))*erfc(sqrt qrt(0.9*EbNo)*sin(pi/alphabet_M)); 0.9*EbNo,'psk',alphabet_M,'nondiff'); ading(EbNo,'qam',alphabet_M,1); ading(EbNo,'qam',alphabet_M,1); ading(EbNo,'psk',alphabet_M,1); ,EbNo,S_err(5,:),'*-r',EbNo,S_err(6,:),'*-k'); ((1.5*EbNo)/(alphabet_M-1))));

legend('BPSK Mod','QPSK Mod','16QAM Mod','64QAM Mod') ylabel('Probability ofError') xlabel('SNR dB') grid on axis([0 300.000011]); semilogy(EbNo,Pr_err(2,:),'-c',EbNo,Pr_err(3,:),'-b' figure() legend('BPSK Mod','QPSK Mod','16QAM Mod','64QAM Mod') ylabel('Theoritical ValueofSER') xlabel('SNR dB') grid on axis([0 500.000011]); r',EbNo,SERtheory(6,:),'*-k'); semilogy(EbNo,SERtheory(2,:),'+c',EbNo,SERt figure() legend('BPSK','QPSK','16QAM','64QAM') heory(3,:),'-b',EbNo,SERtheory(5,:),'*-

,EbNo,Pr_err(5,:),'*-r',EbNo,Pr_err(6,:),'*-k');