Results 1  10
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25
HighSNR power offset in multiantenna communication
 IEEE Transactions on Information Theory
, 2005
"... Abstract—The analysis of the multipleantenna capacity in the high regime has hitherto focused on the high slope (or maximum multiplexing gain), which quantifies the multiplicative increase as a function of the number of antennas. This traditional characterization is unable to assess the impact of ..."
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Cited by 60 (14 self)
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Abstract—The analysis of the multipleantenna capacity in the high regime has hitherto focused on the high slope (or maximum multiplexing gain), which quantifies the multiplicative increase as a function of the number of antennas. This traditional characterization is unable to assess the impact of prominent channel features since, for a majority of channels, the slope equals the minimum of the number of transmit and receive antennas. Furthermore, a characterization based solely on the slope captures only the scaling but it has no notion of the power required for a certain capacity. This paper advocates a more refined characterization whereby, as a function of �f, the high capacity is expanded as an affine function where the impact of channel features such as antenna correlation, unfaded components, etc., resides in the zeroorder term or power offset. The power offset, for which we find insightful closedform expressions, is shown to play a chief role for levels of practical interest. Index Terms—Antenna correlation, channel capacity, coherent communication, fading channels, high analysis, multiantenna arrays, Ricean channels.
Impact of antenna correlation on the capacity of multiantenna channels
 IEEE TRANS. INFORM. THEORY
, 2005
"... This paper applies random matrix theory to obtain analytical characterizations of the capacity of correlated multiantenna channels. The analysis is not restricted to the popular separable correlation model, but rather it embraces a more general representation that subsumes most of the channel model ..."
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Cited by 52 (3 self)
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This paper applies random matrix theory to obtain analytical characterizations of the capacity of correlated multiantenna channels. The analysis is not restricted to the popular separable correlation model, but rather it embraces a more general representation that subsumes most of the channel models that have been treated in the literature. For arbitrary signaltonoise ratios @ A, the characterization is conducted in the regime of large numbers of antennas. For the low and high regions, in turn, we uncover compact capacity expansions that are valid for arbitrary numbers of antennas and that shed insight on how antenna correlation impacts the tradeoffs among power, bandwidth, and rate.
Multipleantenna capacity in the lowpower regime
 IEEE TRANS. INFORM. THEORY
, 2003
"... This paper provides analytical characterizations of the impact on the multipleantenna capacity of several important features that fall outside the standard multipleantenna model, namely: i) antenna correlation, ii) Ricean factors, iii) polarization diversity, and iv) outofcell interference; all ..."
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Cited by 44 (9 self)
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This paper provides analytical characterizations of the impact on the multipleantenna capacity of several important features that fall outside the standard multipleantenna model, namely: i) antenna correlation, ii) Ricean factors, iii) polarization diversity, and iv) outofcell interference; all in the regime of low signaltonoise ratio. The interplay of rate, bandwidth, and power is analyzed in the region of energy per bit close to its minimum value. The analysis yields practical design lessons for arbitrary number of antennas in the transmit and receive arrays.
Capacity of MIMO Channels: Asymptotic Evaluation Under Correlated Fading
 IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS
, 2003
"... This paper investigates the asymptotic uniform power allocation capacity of frequency nonselective multipleinput multipleoutput channels with fading correlation at either the transmitter or the receiver. We consider the asymptotic situation, where the number of inputs and outputs increase without ..."
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Cited by 18 (1 self)
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This paper investigates the asymptotic uniform power allocation capacity of frequency nonselective multipleinput multipleoutput channels with fading correlation at either the transmitter or the receiver. We consider the asymptotic situation, where the number of inputs and outputs increase without bound at the same rate. A simple uniparametric model for the fading correlation function is proposed and the asymptotic capacity per antenna is derived in closed form. Although the proposed correlation model is introduced only for mathematical convenience, it is shown that its shape is very close to an exponentially decaying correlation function. The asymptotic expression obtained provides a simple and yet useful way of relating the actual fading correlation to the asymptotic capacity per antenna from a purely analytical point of view. For example, the asymptotic expressions indicate that fading correlation is more harmful when arising at the side with less antennas. Moreover, fading correlation does not influence the rate of growth of the asymptotic capacity per receive antenna with high 0 .
On the Outage Capacity of Correlated MultiplePath MIMO Channels
, 2005
"... The use of multiantenna arrays in both transmission and reception has been shown to dramatically increase the throughput of wireless communication systems. As a result there has been considerable interest in characterizing the ergodic average of the mutual information for realistic correlated chan ..."
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Cited by 11 (0 self)
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The use of multiantenna arrays in both transmission and reception has been shown to dramatically increase the throughput of wireless communication systems. As a result there has been considerable interest in characterizing the ergodic average of the mutual information for realistic correlated channels. Here, an approach is presented that provides analytic expressions not only for the average, but also the higher cumulant moments of the distribution of the mutual information for zeromean Gaussian MIMO channels with the most general multipath covariance matrices when the channel is known at the receiver. These channels include multitap delay paths, as well as general channels with covariance matrices that cannot be written as a Kronecker product, such as dualpolarized antenna arrays with general correlations at both transmitter and receiver ends. The mathematical methods are formally valid for large antenna numbers, in which limit it is shown that all higher cumulant moments of the distribution, other than the first two scale to zero. Thus, it is confirmed that the distribution of the mutual information tends to a Gaussian, which enables one to calculate the outage capacity. These results are quite accurate even in the case of a few antennas, which makes this approach applicable to realistic situations.
Capacityapproaching rate function for layered multiantenna architectures
 IEEE Trans. Wireless Commun
, 2003
"... Abstract—The simultaneous use of multiple transmit and receive antennas can unleash very large capacity increases in rich multipath environments. Although such capacities can be approached by layered multiantenna architectures with perantenna rate control, the need for shortterm feedback arises as ..."
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Cited by 6 (3 self)
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Abstract—The simultaneous use of multiple transmit and receive antennas can unleash very large capacity increases in rich multipath environments. Although such capacities can be approached by layered multiantenna architectures with perantenna rate control, the need for shortterm feedback arises as a potential impediment, in particular as the number of antennas—and, thus, the number of rates to be controlled—increases. What we show, however, is that the need for shortterm feedback in fact vanishes as the number of antennas and/or the diversity order increases. Specifically, the rate supported by each transmit antenna becomes deterministic and a sole function of the signaltonoise, the ratio of transmit and receive antennas, and the decoding order, all of which are either fixed or slowly varying. More generally, we illustrate—through this specific derivation—the relevance of some established random codedivision multipleaccess results to the singleuser multiantenna problem. Index Terms—Adaptive arrays, antenna diversity, channel capacity, fading channels, multipleantenna information theory, multiuser detection. I.
MultipleInput MultipleOutput Wireless Communication Systems with Cochannel Interference
, 2003
"... To meet the requirement of very high data rates for wireless Internet and multimedia services, multiple transmitting and multiple receiving antennas have been proposed for fourth generation wireless systems. In cellular systems, performance is limited by fading and cochannel interference from other ..."
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Cited by 3 (2 self)
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To meet the requirement of very high data rates for wireless Internet and multimedia services, multiple transmitting and multiple receiving antennas have been proposed for fourth generation wireless systems. In cellular systems, performance is limited by fading and cochannel interference from other users. Most of the current studies on multipleinput multipleoutput (MIMO) systems assume that the cochannel interference is both spatially and temporally white. In this thesis, we focus on MIMO systems under both spatially and temporally colored interference. In MIMO systems, diversity gain is effectively achieved by the multiple receiving antennas. Outage performances of several receive diversity schemes are analytically compared for an interferencelimited environment in a Rayleigh fading channel. We investigate three diversity schemes: a practical variation of maximalratio combining, equalgain combining (EGC) and selection combining (SC). An exact outage probability expression is derived for EGC by accurately calculating the interference power at the output of the combiner. It is found that the relative performance between EGC and SC depends on the
Channel Estimation and Data Detection for MIMO Systems under Spatially and Temporally Colored Interference
 EURASIP J. Appl. Signal Process
, 2003
"... The impact of interference on multipleinput multipleoutput (MIMO) systems has attracted recent interest. Most studies of channel estimation and data detection for MIMO systems consider spatially and temporally white interference at the receiver. In this paper, we address channel estimation, inte ..."
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Cited by 3 (0 self)
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The impact of interference on multipleinput multipleoutput (MIMO) systems has attracted recent interest. Most studies of channel estimation and data detection for MIMO systems consider spatially and temporally white interference at the receiver. In this paper, we address channel estimation, interference correlation estimation and data detection for MIMO systems under both spatially and temporally colored interference. We examine the case of one dominant interferer in which the data rate of the desired user could be the same or a multiple of that of the interferer. Assuming known temporal interference correlation as a benchmark, we derive maximumlikelihood estimates of the channel matrix and spatial interference correlation matrix, and apply these estimates to a generalized version of the BLAST (Bell Labs Layered SpaceTime) ordered data detection algorithm. We then investigate the performance loss by not exploiting interference correlation. For a (5, 5) MIMO system undergoing independent Rayleigh fading, we observe that exploiting both spatial and temporal interference correlation in channel estimation and data detection results in potential gains of 1.5dB and 4dB for an interferer operating at the same data rate and at half the data rate, respectively. Ignoring temporal correlation, it is found that spatial correlation accounts for about 1 db of this gain.
Large n analysis of amplifyandforward MIMO relay channels with correlated Rayleigh fading
 IEEE Trans. Inform. Theory
, 2008
"... In this correspondence the cumulants of the mutual information of the flat Rayleigh fading amplifyandforward MIMO relay channel without direct link between source and destination are derived in the large array limit. The analysis is based on the replica trick and covers both spatially independent ..."
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Cited by 2 (0 self)
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In this correspondence the cumulants of the mutual information of the flat Rayleigh fading amplifyandforward MIMO relay channel without direct link between source and destination are derived in the large array limit. The analysis is based on the replica trick and covers both spatially independent and correlated fading in the first and the second hop, while beamforming at all terminals is restricted to deterministic weight matrices. Expressions for mean and variance of the mutual information are obtained. Their parameters are determined by a nonlinear equation system. All higher cumulants are shown to vanish as the number of antennas n goes to infinity. In conclusion the distribution of the mutual information I becomes Gaussian in the large n limit and is completely characterized by the expressions obtained for mean and variance of I. Comparisons with simulation results show that the asymptotic results serve as excellent approximations for systems with only few antennas at each node. The derivation of the results follows the technique formalized by Moustakas et al. in [1]. Although the evaluations are more involved for the MIMO relay channel compared to pointtopoint MIMO channels, the structure of the results is surprisingly simple again. In particular an elegant formula for the mean of the mutual information is obtained, i.e., the ergodic capacity of the twohop amplifyandforward MIMO relay channel without direct link. Index Terms MIMO relay channel, amplifyandforward, replica analysis, random matrix theory, large antenna number limit, cumulants of mutual information, correlated channels. I.
MIMO capacity with channel state information at the transmitter
 in International Symposium on Spread Spectrum Techniques and Applications
, 2004
"... Abstract — This paper presents analytical expressions for the capacity of singleuser multiantenna channels, known instantaneously by both transmitter and receiver, at moderate and high signaltonoise ratios. Fading channels with both uncorrelated and correlated antennas are encompassed. The chara ..."
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Cited by 2 (0 self)
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Abstract — This paper presents analytical expressions for the capacity of singleuser multiantenna channels, known instantaneously by both transmitter and receiver, at moderate and high signaltonoise ratios. Fading channels with both uncorrelated and correlated antennas are encompassed. The characterization is conducted primarily in the limit of large numbers of antennas, with accompanying examples that illustrate the validity of the results for even small numbers thereof. In the absence of correlation, the capacity is also tightly bounded for fixed numbers of antennas with compact closedform expressions. I.