Limited feedback for antenna selection in MIMO-OFDM systems

Abstract

An antenna selection method based on channel state information (CSI) is proposed for an MIMO-OFDM system. In this method, the receiver of the system exploits selection combing to demodulate received signals and estimates the CSI of each pair of transmit and receive antennas. For each subchannel of the system, the transmit antenna in the pair with the maximum magnitude of subchannel response is selected to carry a data sym- bol. The transmitter then is informed of the selection through a feedback channel. As a result, the probability that the magnitude of the subchannel response is small becomes much lower. Since most symbol errors occur while the magnitude of the subchannel response is small, the symbol error rate (SER) of the system can be significantly reduced. The SER expressions for BPSK and M-QAM are provided. Moreover, we combine this method with full-rate full-diversity space-frequency codes. Performance of the space-frequency code is dramatically improved.