A Simple Cooperative Diversity Method Based on Network Path Selection Aggelos Bletsas, Member, IEEE, Ashish Khisti, Student Member, IEEE, David P
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Performance Comparisons of MIMO Techniques with Application to WCDMA Systems
EURASIP Journal on Applied Signal Processing 2004:5, 649–661 c 2004 Hindawi Publishing Corporation Performance Comparisons of MIMO Techniques with Application to WCDMA Systems Chuxiang Li Department of Electrical Engineering, Columbia University, New York, NY 10027, USA Email: [email protected] Xiaodong Wang Department of Electrical Engineering, Columbia University, New York, NY 10027, USA Email: [email protected] Received 11 December 2002; Revised 1 August 2003 Multiple-input multiple-output (MIMO) communication techniques have received great attention and gained significant devel- opment in recent years. In this paper, we analyze and compare the performances of different MIMO techniques. In particular, we compare the performance of three MIMO methods, namely, BLAST, STBC, and linear precoding/decoding. We provide both an analytical performance analysis in terms of the average receiver SNR and simulation results in terms of the BER. Moreover, the applications of MIMO techniques in WCDMA systems are also considered in this study. Specifically, a subspace tracking algo- rithm and a quantized feedback scheme are introduced into the system to simplify implementation of the beamforming scheme. It is seen that the BLAST scheme can achieve the best performance in the high data rate transmission scenario; the beamforming scheme has better performance than the STBC strategies in the diversity transmission scenario; and the beamforming scheme can be effectively realized in WCDMA systems employing the subspace tracking and the quantized feedback approach. Keywords and phrases: BLAST, space-time block coding, linear precoding/decoding, subspace tracking, WCDMA. 1. INTRODUCTION ing power and/or rate over multiple transmit antennas, with partially or perfectly known channel state information [7]. -
Systems and Techniques for Multicell-MIMO and Cooperative Relaying in Wireless Networks Agisilaos Papadogiannis
Systems and Techniques for Multicell-MIMO and Cooperative Relaying in Wireless Networks Agisilaos Papadogiannis To cite this version: Agisilaos Papadogiannis. Systems and Techniques for Multicell-MIMO and Cooperative Relaying in Wireless Networks. Electronics. Télécom ParisTech, 2009. English. pastel-00598244 HAL Id: pastel-00598244 https://pastel.archives-ouvertes.fr/pastel-00598244 Submitted on 5 Jun 2011 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. THESIS In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy from TELECOM ParisTech Specialization: Electronics and Communications Agisilaos Papadogiannis Systems and Techniques for Multicell-MIMO and Cooperative Relaying in Wireless Networks Thesis defended on the 11th of December 2009 before a committee composed of: President Prof. Jean-Claude Belfiore, TELECOM ParisTech, France Reviewers Prof. M´erouaneDebbah, SUPELEC, France Prof. Gema Pi~nero,Universidad Politechnica de Valencia, Spain Examiners Dr. Rodrigo de Lamare, University of York, UK Dr. Eric Hardouin, Orange Labs, France Thesis supervisor Prof. David Gesbert, EURECOM, France THESE pr´esent´eepour obtenir le grade de Docteur de TELECOM ParisTech Sp´ecialit´e:Electronique et Communications Agisilaos Papadogiannis Syst`emeset Techniques MIMO Coop´eratifdans les R´eseauxMulti-cellulaires Sans Fil Th`esesoutenue le 11 d´ecembre 2009 devant le jury compos´ede: Pr´esident Prof. -
MIMO Systems and Transmit Diversity 1 Introduction 2 MIMO Capacity Analysis
MIMO Systems and Transmit Diversity 1 Introduction So far we have investigated the use of antenna arrays in interference cancellation and for receive diversity. This final chapter takes a broad view of the use of antenna arrays in wireless communi- cations. In particular, we will investigate the capacity of systems using multiple transmit and/or multiple receive antennas. This provides a fundamental limit on the data throughput in multiple- input multiple-output (MIMO) systems. We will also develop the use of transmit diversity, i.e., the use of multiple transmit antennas to achieve reliability (just as earlier we used multiple receive antennas to achieve reliability via receive diversity). The basis for receive diversity is that each element in the receive array receives an independent copy of the same signal. The probability that all signals are in deep fade simultaneously is then significantly reduced. In modelling a wireless communication system one can imagine that this capability would be very useful on transmit as well. This is especially true because, at least in the near term, the growth in wireless communications will be asymmetric internet traffic. A lot more data would be flowing from the base station to the mobile device that is, say, asking for a webpage, but is receiving all the multimedia in that webpage. Due to space considerations, it is more likely that the base station antenna comprises multiple elements while the mobile device has only one or two. In addition to providing diversity, intuitively having multiple transmit/receive antennas should allow us to transmit data faster, i.e., increase data throughput. -
Introduction for Cooperative Diversity and Virtual MIMO
IntroductionIntroduction forfor CooperativeCooperative DiversityDiversity andand VirtualVirtual MIMOMIMO Hsin-Yi Shen Apr 27, 2007 4/27/2007 Rensselaer Polytechnic Institute 1 OutlineOutline Introduction Cooperative Diversity and Virtual MIMO Cooperative MIMO Cooperative FEC Conclusions 4/27/2007 Rensselaer Polytechnic Institute 2 Introduction MIMO: degree-of-freedom gain & diversity gains However, MIMO requires multiple antennas at sources and receivers Cooperative diversity => achieve spatial diversity with even one antenna per-node (eg: MISO, SIMO, MIMO) Cooperative MIMO: special case of coop. diversity Achieve MIMO gains even with one antenna per-node. Eg: open-spectrum meshed/ad-hoc networks, sensor networks, backhaul from rural areas Cooperative FEC: link layer cooperation scheme for multi-hop wireless networks and sensor networks 4/27/2007 Rensselaer Polytechnic Institute 3 CooperativeCooperative DiversityDiversity Motivation In MIMO, size of the antenna array must be several times the wavelength of the RF carrier unattractive choice to achieve receive diversity in small handsets/cellular phones Cooperative diversity: Transmitting nodes use idle nodes as relays to reduce multi-path fading effect in wireless channels Methods Amplify and forward Decode and forward Coded Cooperation 4/27/2007 Rensselaer Polytechnic Institute 4 CooperativeCooperative DiversityDiversity SchemesSchemes Amplify and forward Decode and forward Coded cooperation amplify decode 0101… N1 bits N2 bits forward Frame 2 Frame 1 Relay node Relay -
Multiple Antenna Technologies
Multiple Antenna Technologies Manar Mohaisen | YuPeng Wang | KyungHi Chang The Graduate School of Information Technology and Telecommunications INHA University ABSTRACT the receiver. Alamouti code is considered as the simplest transmit diversity scheme while the receive diversity includes maximum ratio, equal gain and selection combining Multiple antenna technologies have methods. Recently, cooperative received high attention in the last few communication was deeply investigated as a decades for their capabilities to improve the mean of increasing the communication overall system performance. Multiple-input reliability by not only considering the multiple-output systems include a variety of mobile station as user but also as a base techniques capable of not only increase the station (or relay station). The idea behind reliability of the communication but also multiple antenna diversity is to supply the impressively boost the channel capacity. In receiver by multiple versions of the same addition, smart antenna systems can increase signal transmitted via independent channels. the link quality and lead to appreciable On the other hand, multiple antenna interference reduction. systems can tremendously increase the channel capacity by sending independent signals from different transmit antennas. I. Introduction BLAST spatial multiplexing schemes are a good example of such category of multiple Multiple antennas technologies proposed antenna technologies that boost the channel for communications systems have gained capacity. much attention in the last few years because In addition, smart antenna technique can of the huge gain they can introduce in the significantly increase the data rate and communication reliability and the channel improve the quality of wireless transmission, capacity levels. Furthermore, multiple which is limited by interference, local antenna systems can have a big contribution scattering and multipath propagation. -
Performance Analysis of Diversity Techniques for Wireless Communication System
1 Performance Analysis of Diversity Techniques for Wireless Communication System Md. Jaherul Islam [email protected] This Thesis is a part (30 ECTS) of Master of Science degree (120 ECTS) in Electrical Engineering emphasis on Telecommunication Blekinge Institute of Technology February 12 Blekinge Institute of Technology School of Engineering Department of Telecommunication Supervisor: Magnus G Nilsson Examiner: Magnus G Nilsson Contact: [email protected] 2 Abstract Different diversity techniques such as Maximal-Ratio Combining (MRC), Equal-Gain Combining (EGC) and Selection Combining (SC) are described and analyzed. Two branches (N=2) diversity systems that are used for pre-detection combining have been investigated and computed. The statistics of carrier to noise ratio (CNR) and carrier to interference ratio (CIR) without diversity assuming Rayleigh fading model have been examined and then measured for diversity systems. The probability of error ( ) vs CNR and ( ) versus CIR have also been obtained. The fading dynamic range of the instantaneous CNR and CIR is reduced remarkably when diversity systems are used [1]. For a certain average probability of error, a higher valued average CNR and CIR is in need for non-diversity systems [1]. But a smaller valued of CNR and CIR are compared to diversity systems. The overall conclusion is that maximal-ratio combining (MRC) achieves the best performance improvement compared to other combining methods. Diversity techniques are very useful to improve the performance of high speed wireless channel to transmit data and information. The problems which considered in this thesis are not new but I have tried to organize, prove and analyze in new ways. -
Performance Analysis of Cooperative Mimo Systems Using Decode and Forward Relaying
19th European Signal Processing Conference (EUSIPCO 2011) Barcelona, Spain, August 29 - September 2, 2011 PERFORMANCE ANALYSIS OF COOPERATIVE MIMO SYSTEMS USING DECODE AND FORWARD RELAYING Emna Ben Yahia and Hatem Boujemaa Higher School of Communications of Tunis/TECHTRA Research Unit, University of Carthage, Tunisia [email protected], [email protected] ABSTRACT of cooperative MIMO systems. Then we derive the expres- In this paper, considering a source, a relay and a destina- sion of the diversity order. tion with multiple antennas, we provide the exact Bit Er- The paper is organized as follows. Sections 2, 3 and 4 ror Probability (BEP) of dual-hop cooperative Multiple Input presents the performance analysis of cooperative MIMO sys- Multiple Output (MIMO) systems using Decode and For- tems using DF relaying respectively in the absence and pres- ward (DF) relaying for Binary Phase Shift Keying (BPSK) ence of a direct link. For the case where we don’t have a modulation assuming independent and identically distributed direct link, we study two scenarios. The first concerns sys- (i.i.d.) Rayleigh fading channels. When the source or the re- tems where the relay has a single transmit antenna and the lay has multiple antennas, it employs an Orthogonal Space second is about systems where the relay has multiple trans- Time Block Code (OSTBC) to transmit. The receiver uses mit antennas. Section 5 gives some numerical and simulation a Maximum Likelihood (ML) decoder. We derive the ex- results. Section 6 draws some conclusions. pressions of the Moment Generating Functions (MGF), the Probability Density Functions (PDF) of the Signal-to-Noise Ratio (SNR), the exact and asymptotic BEP at the destination 2. -
Great Expectations: the Value of Spatial Diversity in Wireless Networks
Great Expectations: The Value of Spatial Diversity in Wireless Networks SUHAS N. DIGGAVI, MEMBER, IEEE, NAOFAL AL-DHAHIR, SENIOR MEMBER, IEEE, A. STAMOULIS, MEMBER, IEEE, AND A. R. CALDERBANK, FELLOW, IEEE Invited Paper In this paper, the effect of spatial diversity on the throughput The challenge here is that Moore’s Law does not seem to and reliability of wireless networks is examined. Spatial diversity apply to rechargeable battery capacity, and though the den- is realized through multiple independently fading transmit/re- sity of transistors on a chip has consistently doubled every ceive antenna paths in single-user communication and through independently fading links in multiuser communication. Adopting 18 mo, the energy density of batteries only seems to double spatial diversity as a central theme, we start by studying its every 10 years. This need to conserve energy (see [2] and ref- information-theoretic foundations, then we illustrate its benefits erences therein) leads us to focus on what is possible when across the physical (signal transmission/coding and receiver signal signal processing at the terminal is limited. Throughout this processing) and networking (resource allocation, routing, and paper, we use the cost and complexity of the receiver to applications) layers. Throughout the paper, we discuss engineering intuition and tradeoffs, emphasizing the strong interactions be- bound the resources available for signal processing. Wireless tween the various network functionalities. spectrum itself is a valuable resource that also needs to be conserved given the economic imperative of return on multi- Keywords—Ad hoc networks, channel estimation, diversity, fading channels, hybrid networks, information theory for wireless billion-dollar investments by wireless carriers [1]. -
Cooperative Diversity in Wireless Networks: Relay Selection and Medium Access
Helmut Leopold Adam Matr.-Nr. 9830200 Cooperative Diversity in Wireless Networks: Relay Selection and Medium Access DISSERTATION zur Erlangung des akademischen Grades Doktor der technischen Wissenschaften Alpen-Adria-Universit¨at Klagenfurt Fakult¨at fur¨ Technische Wissenschaften Begutachter: Univ.-Prof. Dr.-Ing. Christian Bettstetter Institut fur¨ Vernetzte und Eingebettete Systeme Alpen-Adria-Universit¨at Klagenfurt Univ.-Prof. Dr. Holger Karl Institut fur¨ Informatik Universit¨at Paderborn 08/2011 Declaration of honor I hereby confirm on my honor that I personally prepared the present academic work and carried out myself the activities directly involved with it. I also con- firm that I have used no resources other than those declared. All formulations and concepts adopted literally or in their essential content from printed, un- printed or Internet sources have been cited according to the rules for academic work and identified by means of footnotes or other precise indications of source. The support provided during the work, including significant assistance from my supervisor has been indicated in full. The academic work has not been submitted to any other examination authority. The work is submitted in printed and electronic form. I confirm that the content of the digital version is completely identical to that of the printed version. I am aware that a false declaration will have legal consequences. (Signature) (Place, date) Cooperative Diversity in Wireless Networks: Relay Selection and Medium Access Wireless communication systems suffer from a phenomenon called small scale fading which causes rapid and unpredictable fluctuations in the received signal strengths. Traditional methods to mitigate small scale fading effects impose re- strictions on the data exchange process and/or the used hardware which limit their applicability. -
Diversity Diversity Macrodiversity Microdiversity
Ch13. Diversity Instructor: • Mohammed Taha O. El Astal LOGO 13.1 Introduction AWGN channels Rayleigh Fading In AWGN, it may that a 10-dB SNR leads to BERs on the order of 10−4. but in fading channels, we need an SNR on the order of 40 dB in order to achieve a 10−4 BER, which is clearly unpractical. CONT. deep fading (very low SNR) The reason ??? is the fading of the channel; since the fading cause to have an attenuation being large, and thus of the instantaneous SNR being low, so the BER be high. CONT. The Solution!!!! Make sure that the SNR at Rx. has a smaller probability of being low. =make sure that the signal has a smaller probability to have a large attenuation 13.1.1 Principle of Diversity The principle of diversity is to ensure that the same information reaches the receiver (RX) on statistically independent channels. Example: SNR BER-DFSK If Pnoise is 50 pW. Consider the following two cases : 0dB 0.5 An AWGN channel with Psig,avg is 1 nW. A fading channel where during 90% of the time the ....... …... received power is 1.11 nW, while for the remainder, it is …… …… zero. 13dB 10−9 1. Compute BER for the case of AWGN channel. 13.5dB 10−10 2. Compute avg. BER with assuming it is selection diversity in the following cases: a. one received antenna. b. two received antenna. c. three received antenna 13.1.2 Definition of the Correlation Coefficient Any correlation between the fading of the channels decreases the effectiveness of diversity, why?? The most important one is the correlation coefficient of signal envelopes x and y: For two statistically independent signals E{xy} = E{x}E{y} ρxy=0 Signals are often said to be “effectively” decorrelated if ρ is below a certain threshold (typically 0.5 or 0.7). -
DIVERSITY TECHNIQUES Prepared by Deepa.T, Asst.Prof. /TCE
DIVERSITY TECHNIQUES Prepared by Deepa.T, Asst.Prof. /TCE Introduction •Three techniques are used independently or in tandem to improve receiver signal quality •Equalization compensates for ISI created by multipath with time dispersive channels (W>BC) ¾Linear equalization, nonlinear equalization •Diversity also compensates for fading channel impairments, and is usually implemented by using two or more receiving antennas ¾Spatial diversity, antenna polarization diversity, frequency diversity, time diversity Diversity Diversity: It is the technique used to compensate for fading channel impairments. It is implemented by using two or more receiving antennas. While Equalization is used to counter the effects of ISI, Diversity is usually employed to reduce the depth and duration of the fades experienced by a receiver in a flat fading channel. These techniques can be employed at both base station and mobile receivers. Spatial Diversity is the most widely used diversity technique. Spatial Diversity Technique‐ A Brief Description In this technique multiple antennas are strategically spaced and connected to common receiving system. While one antenna sees a signal null, one of the other antennas may see a signal peak, and the receiver is able to select the antenna with the best signal at any time. The CDMA systems use Rake receivers which provide improvement through time diversity. Diversity Techniques‐ Highlights • Unlike Equalization, Diversity requires no training overhead as a transmitter doesn’t require one. •It provides significant link improvement with little added cost. •It exploits random nature of wave propagation by finding independent ( uncorrelated) signal paths for communication. Fundamentals of Equalization ISI has been recognized as the major obstacle to high speed data transmission over mobile radio channels. -
The Multiply-Detected Macrodiversity Scheme for Wireless Cellular Systems
506 IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 47, NO. 2, MAY 1998 The Multiply-Detected Macrodiversity Scheme for Wireless Cellular Systems Zygmunt J. Haas, Senior Member, IEEE, and Chih-Peng Li, Member, IEEE Abstract—In this paper, the multiply-detected macrodiversity 1) the signal1 with the strongest received power—the (S) (MDM) scheme is proposed for wireless cellular systems. As diversity; opposed to the traditional macrodiversity schemes, in which at 2) the signal with the largest signal-to-interference ratio any time a signal from only one base station is selected, in the MDM scheme there is no selection, but all the received signals (SIR)—the signal-to-interference (S/I) diversity; are detected, and a maximum-likelihood decision algorithm is 3) the signal with the largest signal plus interference employed to maximize the probability of correct decision. We power—the (S I) diversity. study the performance of the MDM scheme and compare it with Of course, as the SIR directly determines the bit-error rate the performance of the traditional selection-based macrodiversity schemes. Depending on the propagation parameters, our results (BER), the (S/I) diversity corresponds to the best performing show that through the use of the MDM scheme, significant system. Thus, we adopt the (S/I) diversity as the comparison improvement in the bit-error rate (BER) can be achieved. For basis for the MDM scheme. However, practically, the (S/I) R instance, if the outage probability is defined as BER above 10 , diversity is also the most difficult scheme to implement. the outage is eliminated at least 45% of the time as compared with Various studies have analyzed network architectures em- signal-to-interference (S/I) diversity, for a propagation attenua- tion exponent of 4.0 and shadowing standard deviation of 4.0 ploying selection-based macroscopic diversity.