TY - JOUR

T1 - On the achievable sum-rate of correlated MIMO multiple access channel with imperfect channel estimation

AU - Musavian, Leila

AU - Aissa, Sonia

PY - 2008/7

Y1 - 2008/7

N2 - We study upper and lower bounds on the achievable sum-rate of a correlated MIMO MAC with channel estimation error at the receiver when the correlation information is available to the users' transmitters, and prove that, for Gaussian input signals with arbitrary input covariance matrices, the gap between these bounds does not exceed a limiting value at any input transmit power. We further prove that in systems with uniform input power utilization over the transmit antennas, the gap between the mutual information bounds increases monotonically as the input power of each user increases. Furthermore, we show that in the absence of correlation, the gap between the mutual information bounds is maximum for beamforming and minimum for uniform input power allocation over the transmit antennas. We further prove that utilizing the input power of each user towards the directions of the eigenvectors of its transmit correlation matrix maximizes the mutual information lower bound. Moreover, we derive the transmit directions that maximize the mutual information lower and upper bounds in an uncorrelated MIMO MAC with delayed feedback from the receiver to the transmitters, and characterize the power allocation of this system in terms of its beamforming range. Numerical simulations are conducted to corroborate our theoretical results.

AB - We study upper and lower bounds on the achievable sum-rate of a correlated MIMO MAC with channel estimation error at the receiver when the correlation information is available to the users' transmitters, and prove that, for Gaussian input signals with arbitrary input covariance matrices, the gap between these bounds does not exceed a limiting value at any input transmit power. We further prove that in systems with uniform input power utilization over the transmit antennas, the gap between the mutual information bounds increases monotonically as the input power of each user increases. Furthermore, we show that in the absence of correlation, the gap between the mutual information bounds is maximum for beamforming and minimum for uniform input power allocation over the transmit antennas. We further prove that utilizing the input power of each user towards the directions of the eigenvectors of its transmit correlation matrix maximizes the mutual information lower bound. Moreover, we derive the transmit directions that maximize the mutual information lower and upper bounds in an uncorrelated MIMO MAC with delayed feedback from the receiver to the transmitters, and characterize the power allocation of this system in terms of its beamforming range. Numerical simulations are conducted to corroborate our theoretical results.

KW - Array signal processing

KW - Channel estimation

KW - Covariance matrix

KW - Delay

KW - Feedback

KW - MIMO

KW - Mutual information

KW - Transmitters

KW - Transmitting antennas

KW - Upper bound

U2 - 10.1109/TWC.2008.060871

DO - 10.1109/TWC.2008.060871

M3 - Journal article

VL - 7

SP - 2549

EP - 2559

JO - IEEE Transactions on Wireless Communications

JF - IEEE Transactions on Wireless Communications

SN - 1536-1276

IS - 7

ER -