Power Control for Space-Time-Coded MIMO Systems With Imperfect Feedback Over Joint Transmit-Receive-Correlated Channel

In this paper, power adaptation strategies for minimizing bit error rate (BER) subject to an average power constraint for orthogonal space-time coded multiple-input multipleoutput (MIMO) systems with mean and covariance feedback over joint transmit-receive correlated channels are presented. We first develop an optimal spatial-only power control (PC) based on an approximated BER bound, which can include the mean feedback only and covariance feedback only as special cases. Using a newly defined fuzzy signal-to-noise ratio (FSNR) criterion, a suboptimal spatial PC scheme with a closed-form expression is derived. This FSNR-based power adaptation not only has the computational complexity less than but also obtain the BER performance close to that of the optimal spatial-only PC scheme. Second, the degrees of freedom in temporal and spatial domains are exploited to derive a joint spatio-temporal PC with the use of FSNR strategy to minimize the average BER subject to a long term average power constraint with mean and covariance feedback. Simulation results show that the proposed two spatial-only PC schemes can provide BER lower than that of the equal power allocation, and obtain almost the same performance as the existing spatial-only optimal scheme but have lower computational complexity. Moreover, they outperform the PC schemes with mean or covariance feedback only. Most importantly, the new joint spatio-temporal PC scheme substantially outperforms all the spatial-only PC schemes.