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Selected Areas in Communications, IEEE Journal on

Issue 3 • Date April 2003

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Displaying Results 1 - 17 of 17
  • Guest editorial: MIMO systems and applications. 1

    Publication Year: 2003 , Page(s): 277 - 280
    Cited by:  Papers (8)
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    Freely Available from IEEE
  • Multiple-input-multiple-output measurements and modeling in Manhattan

    Publication Year: 2003 , Page(s): 321 - 331
    Cited by:  Papers (109)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1600 KB) |  | HTML iconHTML  

    Narrowband multiple-input-multiple-output (MIMO) measurements using 16 transmitters and 16 receivers at 2.11 GHz were carried out in Manhattan. High capacities were found for full, as well as smaller array configurations, all within 80% of the fully scattering channel capacity. Correlation model parameters are derived from data. Spatial MIMO channel capacity statistics are found to be well represented by the separate transmitter and receiver correlation matrices, with a median relative error in capacity of 3%, in contrast with the 18% median relative error observed by assuming the antennas to be uncorrelated. A reduced parameter model, consisting of 4 parameters, has been developed to statistically represent the channel correlation matrices. These correlation matrices are, in turn, used to generate H matrices with capacities that are consistent within a few percent of those measured in New York. The spatial channel model reported allows simulations of H matrices for arbitrary antenna configurations. These channel matrices may be used to test receiver algorithms in system performance studies. These results may also be used for antenna array design, as the decay of mobile antenna correlation with antenna separation has been reported here. An important finding for the base transmitter array was that the antennas were largely uncorrelated even at antenna separations as small as two wavelengths. View full abstract»

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  • Turbo-BLAST: performance evaluation in correlated Rayleigh-fading environment

    Publication Year: 2003 , Page(s): 340 - 349
    Cited by:  Papers (18)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (537 KB) |  | HTML iconHTML  

    Theoretical investigations of spatially correlated multitransmit and multireceive (MTMR) links show that not only independently and identically distributed links, but also spatially correlated links can offer linear capacity growth with increasing number of transmit and receive antennas. We explore the suitability of the turbo-BLAST architecture in correlated Rayleigh-fading MTMR environments. In particular, for an MTMR system with a large number of receive antennas, a near optimal performance can be achieved by the turbo-BLAST architecture in spatially and temporarily correlated Rayleigh-fading environments. The performance of turbo-BLAST, in terms of both bit-error rate and spectral efficiency, is analyzed empirically in indoors and correlated outdoor environments. View full abstract»

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  • Space-time block coding for single-carrier block transmission DS-CDMA downlink

    Publication Year: 2003 , Page(s): 350 - 361
    Cited by:  Papers (28)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (755 KB) |  | HTML iconHTML  

    The combination of space-time block coding (STBC) and direct-sequence code-division multiple access (DS-CDMA) has the potential to increase the performance of multiple users in a cellular network. However, if not carefully designed, the resulting transmission scheme suffers from increased multiuser interference (MUI), which dramatically deteriorates the performance. To tackle this MUI problem in the downlink, we combine two specific DS-CDMA and STBC techniques, namely single-carrier block transmission (SCBT) DS-CDMA and time-reversal STBC. The resulting transmission scheme allows for deterministic maximum-likelihood (ML) user separation through low-complexity code-matched filtering, as well as deterministic ML transmit stream separation through linear processing. Moreover, it can achieve maximum diversity gains of NTNR(L+1) for every user in the system, irrespective of the system load, where NT is the number of transmit antennas, NR the number of receive antennas, and L the order of the underlying multipath channels. In addition, it turns out that a low-complexity linear receiver based on frequency-domain equalization comes close to extracting the full diversity in reduced, as well as full load settings. In this perspective, we also develop two (recursive) least squares methods for direct equalizer design. Simulation results demonstrate the outstanding performance of the proposed transceiver compared to competing alternatives. View full abstract»

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  • Feedback assisted transmission subspace tracking for MIMO systems

    Publication Year: 2003 , Page(s): 452 - 463
    Cited by:  Papers (39)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (933 KB) |  | HTML iconHTML  

    This paper describes a feedback assisted stochastic gradient algorithm for transmission tracking of the dominant channel subspaces for multiple-input-multiple-output (MIMO) communications systems. Subspace tracking is introduced as a means of tracking multiple transmission weights, being the MIMO generalization of beam steering in the familiar multiple-input-single-output case. The subspace solution approximates that of water filling (WF) in some cases, without the complete rate/power allocation required by WF. The gain of subspace tracking in low rank systems is demonstrated, particularly, in the case where the number of transmit antennas exceeds the number of receive antennas. Simulations of ergodic capacity show the utility of both subspace tracking in general and of the specific adaptation algorithm, and simulations of frame-error rates show the utility in a specific coding example. View full abstract»

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  • Spectral efficiency of MIMO multiaccess systems with single-user decoding

    Publication Year: 2003 , Page(s): 382 - 394
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (748 KB) |  | HTML iconHTML  

    The use of multiple antennas at the transmitter and the receiver is considered for the uplink of cellular communication systems. The achievable spectral efficiency in bits/s/Hz is used as the criterion for comparing various design choices. The focus is on wideband code-division multiple-access (CDMA) systems when the receiver uses the matched-filter or the minimum mean-squared error detector, followed by single-user decoders. The spreading sequences of the CDMA system are assumed to be random across the users, but could be dependent across the transmit antennas of each user. Using analytical results in the large system asymptote, guidelines are provided for the sequence design across the transmit antennas and for choosing the number of antennas. In addition, comparisons are made between (random) CDMA and orthogonal multiaccess with multiple antennas. It is shown that CDMA, even with single-user decoding, can outperform orthogonal multiaccess when the number of receive antennas is sufficiently large. View full abstract»

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  • On the capacity of a multiple-antenna communication link with channel side information

    Publication Year: 2003 , Page(s): 395 - 405
    Cited by:  Papers (49)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (798 KB) |  | HTML iconHTML  

    We investigate the capacity of a system with multiple transmit and receive antennas, assuming that the transmitter and receiver both have access to (possibly defective) channel-state information. Two different special cases of a general system are studied in detail. Our main results are capacity expressions for these cases and a general conclusion that the encoder can be split into separate "space-time coding" and "direction weighting" or "beamforming," without capacity loss. We also present numerical results illustrating the dependence of capacity on the parameters of a quantization scheme providing channel-state information to the transmitter from the receiver. These results have high practical value since the assumptions behind them are closely related to the ones of the closed-loop mode in the UMTS/WCDMA standard. View full abstract»

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  • Blind detection in MIMO systems via sequential Monte Carlo

    Publication Year: 2003 , Page(s): 464 - 473
    Cited by:  Papers (21)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (824 KB) |  | HTML iconHTML  

    We provide a novel sequential estimation and detection approach for multiple-input-multiple-output (MIMO) systems. The basic idea is to design a probabilistic approximation method for the computation of the maximum a posterior distribution (MAP) via the sequential Monte Carlo methods (SMC). The SMC method has two advantages over the other methods in that it is a blind method and can be computed in parallel. Furthermore, the SMC has characteristics of soft-input and soft-output in nature and, thus, it can be employed as the first stage demodulator in a turbo receiver for a coded MIMO system. Such a turbo receiver successively improves the receiver performance by iteratively exchanging the so-called extrinsic information with the MAP outer channel decoder. Finally, the performance of the proposed sequential Monte Carlo receiver is demonstrated through computer simulations for MIMO systems over single-path and multipath fading channels. View full abstract»

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  • Optimizing MIMO antenna systems with channel covariance feedback

    Publication Year: 2003 , Page(s): 406 - 417
    Cited by:  Papers (75)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (827 KB) |  | HTML iconHTML  

    We consider a narrowband point-to-point communication system with nT transmitters and nR receivers. We assume the receiver has perfect knowledge of the channel, while the transmitter has no channel knowledge. We consider the case where the receiving antenna array has uncorrelated elements, while the elements of the transmitting array are arbitrarily correlated. Focusing on the case where nT=2, we derive simple analytic expressions for the ergodic average and the cumulative distribution function of the mutual information for arbitrary input (transmission) signal covariance. We then determine the ergodic and outage capacities and the associated optimal input signal covariances. We thus show how a transmitter with covariance knowledge should correlate its transmissions to maximize throughput. These results allow us to derive an exact condition (both necessary and sufficient) that determines when beamforming is optimal for systems with arbitrary number of transmitters and receivers. View full abstract»

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  • Analysis and performance of some basic space-time architectures

    Publication Year: 2003 , Page(s): 303 - 320
    Cited by:  Papers (95)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1185 KB) |  | HTML iconHTML  

    In this paper, we discuss some of the most basic architectural superstructures for wireless links with multiple antennas: M at the transmit site and N at the receive site. Toward leveraging the gains of the last half century of coding theory, we emphasize those structures that can be composed using spatially one dimensional coders and decoders. These structures are investigated primarily under a probability of outage constraint. The random matrix channel is assumed to hold steady for such a large number of M-dimensional vector symbol transmission times, that an infinite time horizon Shannon analysis provides useful insights. The resulting extraordinary capacities are contrasted for architectures that differ in the way that they manage self-interference in the presence of additive receiver noise. A universally optimal architecture with a diagonal space-time layering is treated, as is an architecture with horizontal space-time layering and an architecture with a single outer code. Some capacity asymptotes for large numbers of antennas are also included. Some results for frequency selective channels are presented: It is only necessary to feedback M rates, one per transmit antenna, to attain capacity. Also, capacity of an (M,N) link is, in a certain sense, invariant with respect to signaling format. View full abstract»

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  • Impact of the propagation environment on the performance of space-frequency coded MIMO-OFDM

    Publication Year: 2003 , Page(s): 427 - 439
    Cited by:  Papers (145)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1019 KB) |  | HTML iconHTML  

    Previous work on space-frequency coded multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) has been restricted to idealistic propagation conditions. In this paper, using a broadband MIMO channel model taking into account Ricean K-factor, transmit and receive angle spread, and antenna spacing, we study the impact of the propagation environment on the performance of space-frequency coded MIMO-OFDM. For a given space-frequency code, we quantify the achievable diversity order and coding gain as a function of the propagation parameters. We find that while the presence of spatial receive correlation affects all space-frequency codes equally, spatial fading correlation at the transmit array can result in widely varying performance losses. High-rate space-frequency codes such as spatial multiplexing are typically significantly more affected by transmit correlation than low-rate codes such as space-frequency block codes. We show that in the MIMO Ricean case the presence of frequency-selectivity typically results in improved performance compared to the frequency-flat case. View full abstract»

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  • Investigation on MIMO channels in subway tunnels

    Publication Year: 2003 , Page(s): 332 - 339
    Cited by:  Papers (54)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (596 KB) |  | HTML iconHTML  

    The purpose of this paper is to examine the possibilities of increasing the channel capacity in tunnels, and particularly in railway tunnels, due to the use of multiple-input-multiple-output techniques. Many measurement campaigns have been carried out, considering the complicated geometric structure of these tunnels. We determine the channel characteristics by making a statistical analysis of correlation matrices between antennas and singular values of the channel transfer matrix. A comparison between the theoretical and experimental results is also presented. A stochastic channel model is then proposed and validated. View full abstract»

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  • Performance bounds for turbo-coded multiple antenna systems

    Publication Year: 2003 , Page(s): 374 - 381
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB) |  | HTML iconHTML  

    We derive performance bounds for turbo-coded systems with transmit and receive antenna diversity. The bounds are derived by limiting the conditional union bound before averaging over the fading process. It is demonstrated that this approach provides a tight upper bound on the error probability of the turbo-coded multiple antenna systems. We also describe a method for deriving the weight-enumerating function of turbo-coded multiple antenna systems in order to take into account the presence of transmit and receive antenna diversity. Examples of the bounds are presented to illustrate their usefulness. View full abstract»

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  • Prototype experience for MIMO BLAST over third-generation wireless system

    Publication Year: 2003 , Page(s): 440 - 451
    Cited by:  Papers (39)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (932 KB) |  | HTML iconHTML  

    In this paper, a multiple-input-multiple-output (MIMO) extension for a third-generation (3G) wireless system is described. The integration of MIMO concepts within the existing UMTS standard and the associated space-time RAKE receiver are explained. An analysis is followed by a description of an actual experimental MIMO transmitter and receiver architecture, both realized on digital signal processors (DSPs) and FPGAs within a precommercial OneBTS base station. It uses four transmit and four receive antennas to achieve downlink data rates up to 1 Mb/s per user with a spreading factor of 32 and the UMTS chip rate of 3.84 MHz. Furthermore, different MIMO detectors are evaluated, comparing their performance and complexity. System performance is evaluated through simulations and indoor over-the-air measurements. Capacity and bit-error rate measurement results are presented. View full abstract»

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  • From theory to practice: an overview of MIMO space-time coded wireless systems

    Publication Year: 2003 , Page(s): 281 - 302
    Cited by:  Papers (867)  |  Patents (72)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (930 KB) |  | HTML iconHTML  

    This paper presents an overview of progress in the area of multiple input multiple output (MIMO) space-time coded wireless systems. After some background on the research leading to the discovery of the enormous potential of MIMO wireless links, we highlight the different classes of techniques and algorithms proposed which attempt to realize the various benefits of MIMO including spatial multiplexing and space-time coding schemes. These algorithms are often derived and analyzed under ideal independent fading conditions. We present the state of the art in channel modeling and measurements, leading to a better understanding of actual MIMO gains. Finally, the paper addresses current questions regarding the integration of MIMO links in practical wireless systems and standards. View full abstract»

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  • Variable-rate space-time block codes in M-ary PSK systems

    Publication Year: 2003 , Page(s): 362 - 373
    Cited by:  Papers (26)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1101 KB) |  | HTML iconHTML  

    We consider a multiple antenna system when combined array processing with space-time coding is used. We present variable rate space-time block codes for two, three, and four transmit antennas and optimize the transmit power so that the average bit-error rate (BER) is minimized. Numerical results show that this optimum power allocation scheme provides significant gain over the equal power allocation scheme. We then classify all the variable rate space-time block codes having the same code rates and identify the unique code that achieves the lowest BER. We explicitly compute the performance of the variable rate codes over a Rayleigh-fading channel. The proposed variable rate space-time block codes are useful for unequal error protection in multiple transmit antenna systems. View full abstract»

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  • Largest eigenvalue of complex Wishart matrices and performance analysis of MIMO MRC systems

    Publication Year: 2003 , Page(s): 418 - 426
    Cited by:  Papers (150)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (740 KB) |  | HTML iconHTML  

    This paper extends Khatri (1964, 1969) distribution of the largest eigenvalue of central complex Wishart matrices to the noncentral case. It then applies the resulting new statistical results to obtain closed-form expressions for the outage probability of multiple-input-multiple-output (MIMO) systems employing maximal ratio combining (known also as "beamforming" systems) and operating over Rician-fading channels. When applicable these expressions are compared with special cases previously reported in the literature dealing with the performance of (1) MIMO systems over Rayleigh-fading channels and (2) single-input-multiple-output (SIMO) systems over Rician-fading channels. As a double check these analytical results are validated by Monte Carlo simulations and as an illustration of the mathematical formalism some numerical examples for particular cases of interest are plotted and discussed. These results show that, given a fixed number of total antenna elements and under the same scattering condition (1) SIMO systems are equivalent to multiple-input-single-output systems and (2) it is preferable to distribute the number of antenna elements evenly between the transmitter and the receiver for a minimum outage probability performance. View full abstract»

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Aims & Scope

IEEE Journal on Selected Areas in Communications focuses on all telecommunications, including telephone, telegraphy, facsimile, and point-to-point television, by electromagnetic propagation.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Muriel Médard
MIT