WLC31-4: Optimal Signaling for Single Transmit Antenna Selection with Erroneous Feedback

Abstract
We consider a MIMO system where error-prone feedback from the receiver is used by the transmitter to select a single optimum antenna to transmit data. Such error-prone feedback is common in the bandwidth-limited real systems, and is in marked contrast with the idealizations assumed in the selection literature. We show how the signaling assignment, which maps the antenna indices to the codewords that are fed back to indicate the index of the best transmit antenna, affects the performance of transmit antenna selection. The impact is intimately coupled with the receiver design. We derive approximate closed-form expressions for the average symbol error probability of QPSK modulated data in a spatially correlated channel, and then systematically find the optimal signaling assignment. Performance improvements are demonstrated for different antenna topologies without introducing any additional redundancy.