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Home , Mobile radio telephone, Mobile Telephone Service, Nordic Mobile Telephone

Philadelphia University Faculty of Engineering Communication and Electronics Engineering

MOBILE COMMUNICATIONS

(650539)

Part 1

١ Dr. Omar R Daoud Text Book and References

 T. Rappaport, “ Communications: Principles and Practice”, 2nd Edition, Prentice Hall, 2002.  W. Stalling, “Wireless Communications and Networks”, Pearson Education, 2002.  S. Haykin, “Communications Systems”, 4th Edition, John Wiley and Sons., 2001.  A. Yoshihiko, “Introduction to Digital Mobile Communication”, John Wiley and Sons., 1997.  L. William, “ Mobile Cellular : Analog and Digital Systems ”, Mc Graw Hill, 1995.

٢ Dr. Omar R Daoud Course Contents

 Introduction (1 week)  Cellular Concepts, Coverage Principle and Frequency Reuse (2 weeks)  Multichannel and Cochannel Schemes (2 weeks)  Interference: Cochannel and Adjacent Channel (2 weeks)  Fading Models and Prediction of the Median Path Loss (2 weeks)  Modulation Techniques (2 weeks)  Mobile Communication Systems (2 weeks)  Private and Public Access Mobile Radio and Radio Paging (2 weeks)

٣ Dr. Omar R Daoud Mode of Assessment

 First Exam (20%)

 Second Exam (20%)

 Quizzes\Reports\or Projects (10%)

 Final Exam (50%)

٤ Dr. Omar R Daoud Introduction

 Mobile/ Wireless Systems Definitions

 Why Cellular Mobile Systems?

 Mobile Systems Revolutions

٥ Dr. Omar R Daoud First Mobile Radio 1924

٦ Dr. Omar R Daoud Mobile/ Wireless Systems Definitions

 BS: Base Station; fixed station located on either the center or the edge of a coverage region. Consists of radio channels, transmitter and receivers antennas.  MS: a station which is intended for use while in motion at unspecified location.

 Forward Channel/ downlink: The transmission process from BS to MS.

 Reverse Channel/ uplink: The transmission process from MS to BS.  Handoff: a process of automatically changing frequencies as the mobile unit moves into a different frequency zone. Thus, the call can be continued in a new frequency without redialing.  Full Duplex: Transmission and reception on two different channels.  Half Duplex: At any time the user can only transmit or receive information.

 FDD: Frequency Division Duplexing; the radio transmission channels are provided simultaneously for the subscriber and the BS.

٧ Dr. Omar R Daoud Mobile/ Wireless Systems Definitions

 TDD: Time Division Duplexing; A single radio channel can be shared in time between the subscriber and the BS.

: a MS operate in a service area different than the from which service has been subscribed.

 MSC: Mobile Switching Center; connects the BS and MS to the PSTN.  SSB: Single-sideband  FCC: Federal Communications Commission  MTS:  IMTS: Improved Mobile Telephone Service  AMPS: Advanced Service  TACS: Total Access Communication System  NMT:

٨ Dr. Omar R Daoud Mobile/ Wireless Systems Definitions

 GSM: Global System for Mobile Communications  PDC: Personal Digital Cellular  HSCSD: High Speed  GPRS: General Packet Radio Service  EDGE: Enhanced Data rates for Global Evolution

٩ Dr. Omar R Daoud Why Cellular Mobile Systems?

 To Improve: * Service Capability * Service Performance * Frequency Spectrum Utilization

١٠ Dr. Omar R Daoud Why Cellular Mobile Systems?

 Improving the Service Capability In a conventional mobile telephone system: It is usually designed by selecting one or more channels from a specific frequency allocation for use in autonomous geographic zones. Each zone is planned to be as large as possible (the transmitted power must be as high as the federal specifications allows). The user must reinitiate the call when moving into a new zone because the call will be dropped. The number of active users is limited to the number of channels assigned to a particular frequency zone.

١١ Dr. Omar R Daoud Why Cellular Mobile Systems?

 Improving the Service Performance In the conventional mobile telephone systems (MTS, IMTS-MJ and IMTS-MK) a total of 33 channels were allocated. The large number of subscribers created a high blocking probability during the busy hours. Thus a high-capacity systems were needed

١٢ Dr. Omar R Daoud Why Cellular Mobile Systems?

 Improving the Frequency Spectrum Utilization In a conventional mobile telephone system the frequency utilization measurement is defined as the maximum number of subscribers that could be served by one channel at the busy hour.

In such systems the channel can only serve one customer at a time in a whole area. Thus, a new cellular system must be initiated to overcome these limitations. This systems must be: - SSB: divides the allocated frequency band into maximum numbers of channels

- Cellular: reuses the allocated frequency band in different geographical locations

- Spread-spectrum or Frequency-hopped: generates many codes over a wide frequency band

١٣ Dr. Omar R Daoud Cellular Mobile

 Frequency modulation

 Antenna diversity 2 7 5 3 2  Cellular concept 1 6 3  Bell Labs (1957 & 1960) 4 1 6 2 7 4  Frequency reuse 5 2 7 3 5  Typically every 7 cells 1 6 3 4 1  Handoff as caller moves 2 7 5  Modified CO switch

 HLR, paging, handoffs

 Sectors improve reuse

 Every 3 cells possible

١٤ Dr. Omar R Daoud Mobile Systems Revolutions

(AMPS, TACS and NMT): Features: -Analogue systems -FM modulations -Cellular concepts -Hard Handoff

١٥ Dr. Omar R Daoud First Generation

 Advanced Mobile Phone Service (AMPS)  US trials 1978; deployed in Japan (’79) & US (’83)  800 MHz band — two 20 MHz bands  TIA-553  Still widely used in US and many parts of the world  Nordic (NMT)  , , Demark &  Launched 1981; now largely retired  450 MHz; later at 900 MHz (NMT900)  Total Access Communications System (TACS)  British design; similar to AMPS; deployed 1985  Some TACS-900 systems still in use in

١٦ Dr. Omar R Daoud Mobile Systems Revolutions

(GSM, IS-95, PDC): Features : -Digital Mobile phones -Digital modulation - -Error control -Soft Handoff -SMS -High quality voice -More capacity/ each cell are divided among several users.

١٧ Dr. Omar R Daoud Second Generation — 2G

 There are a wide diversity of 2G systems  IS-54/ IS-136 North American TDMA; PDC (Japan)  iDEN  DECT and PHS  IS-95 CDMA (cdmaOne)  GSM

١٨ Dr. Omar R Daoud D-AMPS/ TDMA & PDC

 Speech coded as digital bit stream  Compression plus error protection bits  Aggressive compression limits voice quality  Time division multiple access (TDMA)  3 calls per radio channel using repeating time slices  Deployed 1993 (PDC 1994)  Development through 1980s; bakeoff 1987  IS-54 / IS-136 standards in US TIA  ATT Wireless & Cingular use IS-136 today  Plan to migrate to GSM and then to W-CDMA  PDC dominant cellular system in Japan today  NTT DoCoMo has largest PDC network

١٩ Dr. Omar R Daoud iDEN

 Used by Nextel  proprietary system

 Time division multiple access technology

 Based on GSM architecture  800 MHz private mobile radio (PMR) spectrum

 Just below 800 MHz cellular band  Special protocol supports fast “Push-to-Talk”

 Digital replacement for old PMR services  Nextel has highest APRU in US market due to “Direct Connect” push-to-talk service

٢٠ Dr. Omar R Daoud DECT and PHS

 Also based on time division multiple access  Digital European Cordless Telephony  Focus on business use, i.e. wireless PBX  Very small cells; In building propagation issues  Wide (32 kbps channels)  High-quality voice and/or ISDN data  Personal Handiphone Service  Similar performance (32 kbps channels)  Deployed across Japanese cities (high pop. density)  4 channel base station uses one ISDN BRI line  Base stations on top of phone booths  Legacy in Japan; new deployments in China today

٢١ Dr. Omar R Daoud North American CDMA (cdmaOne)

 Code Division Multiple Access

 All users share same frequency band

 Discussed in detail later as CDMA is basis for

 Qualcomm demo in 1989

 Claimed improved capacity & simplified planning

 First deployment in Hong Kong late 1994

 Major success in Korea (1M subs by 1996)

 Used by Verizon and Sprint in US

 Simplest 3G migration story today

٢٢ Dr. Omar R Daoud cdmaOne — IS-95

 TIA standard IS-95 (ANSI-95) in 1993  IS-95 deployed in the 800 MHz cellular band

 J-STD-08 variant deployed in 1900 MHz US “PCS” band  Evolution fixes bugs and adds data

 IS-95A provides data rates up to 14.4 kbps

 IS-95B provides rates up to 64 kbps (2.)

 Both A and B are compatible with J-STD-08  All variants designed for TIA IS-41 core networks (ANSI 41)

٢٣ Dr. Omar R Daoud GSM

 « Groupe Special Mobile », later changed to « Global System for Mobile »  Joint European effort beginning in 1982  Focus on seamless roaming across Europe  Services launched 1991  Time division multiple access (8 users per 200KHz)  900 MHz band; later extended to 1800MHz  Added 1900 MHz (US PCS bands)  GSM is dominant world standard today  Well defined interfaces; many competitors  Network effect (Metcalfe’s law) took hold in late 1990s  Tri-band GSM phone can roam the world today

٢٤ Dr. Omar R Daoud Mobile Systems Revolutions

 2.5G (HSCSD,GPRS, EDGE): Features : 2.5G is an interim solution designed to allow for improved data rates prior to 3G implementation. A variety of 2.5G techniques are being employed to improve the speed of data for enhanced e-mail and access.

٢٥ Dr. Omar R Daoud Mobile Systems Revolutions

 3G (UMTS, WCDMA): Features : -Digital multimedia handset.  High data transmission rate > 100kbps.

 Providing much more basic voice call. -Dynamic RRM. -Packet data.

٢٦ Dr. Omar R Daoud 3G Vision

 Universal global roaming  Multimedia (voice, data & video)  Increased data rates

 384 kbps while moving

 2 Mbps when stationary at specific locations  Increased capacity (more spectrally efficient)  IP architecture

٢٧ Dr. Omar R Daoud CDMA2000 Pros and Cons

 Evolution from original Qualcomm CDMA

 Now known as cdmaOne or IS-95  Better migration story from 2G to 3G

 cdmaOne operators don’t need additional spectrum

 1xEVD0 promises higher data rates than UMTS, i.e. W- CDMA  Better than W-CDMA(?)

 Arguable (and argued!)  CDMA2000 core network less mature

 cmdaOne interfaces were vendor-specific

 Hopefully CDMA2000 vendors will comply w/ 3GPP2

٢٨ Dr. Omar R Daoud W-CDMA (UMTS)

 Wideband CDMA

 Standard for Universal Mobile Telephone Service (UMTS)  Committed standard for Europe and likely migration path for other GSM operators

 Leverages GSM’s dominant position  Requires substantial new spectrum

 5 MHz each way (symmetric)  Legally mandated in Europe and elsewhere  Sales of new spectrum completed in Europe

 At prices that now seem exorbitant

٢٩ Dr. Omar R Daoud TD-SCDMA

 Time division duplex (TDD)  Chinese development

 Will be deployed in China  Good match for asymmetrical traffic!  Single spectral band (1.6 MHz) possible  Costs relatively low

 Handset smaller and may cost less

 Power consumption lower

 TDD has the highest spectrum efficiency  Power amplifiers must be very linear

 Relatively hard to meet specifications

٣٠ Dr. Omar R Daoud Migration To 3G 2.75G 3G Multimedia Intermediate 2.5G Multimedia 2G Packet Data 1G Digital Voice Analog Voice GPRS GSM W-CDMA EDGE (UMTS) 115 Kbps NMT 9.6 Kbps 384 Kbps Up to 2 Mbps GSM/ TD-SCDMA TDMA GPRS (Overlay) 2 Mbps? TACS 115 Kbps 9.6 Kbps

iDEN iDEN 9.6 Kbps PDC (Overlay) 9.6 Kbps AMPS CDMA 1xRTT CDMA 1X-EV-DV PHS 14.4 Kbps (IP-Based) 144 Kbps Over 2.4 Mbps / 64 Kbps PHS 64 Kbps 2003 - 2004+ 2003+ 2001+ 1992 - 2000+ Source: U.S. Bancorp Piper Jaffray 1984 - 1996+

٣١ Dr. Omar R Daoud Mobile Systems Revolutions

٣٢ Dr. Omar R Daoud Mobile Wireless Spectrum

Bands Frequencies GSM/ (MHz) (MHz) Regions EDGE WCDMA CDMA2000

450 450-467 Europe x x 480 478-496 Europe x 800 824-894 America x x 900 880-960 Europe/APAC x x 1500 Japan PDC x 1700 1750-1870 Korea x 1800 1710-1880 Europe/APAC x x x 1900 1850-1990 America x x x 1885-2025 & 2100 Europe/APAC x x 2100-2200 2500 2500-2690 ITU Proposal x

٣٣ Dr. Omar R Daoud