An Equal Gain Transmission in MIMO Wireless Communications

Abstract

The maximum SNR loss between equal gain transmission (EGT) and the optimal scheme, i.e. maximum ratio transmission (MRT) is 1.05 dB in MISO channels. However, little is known about the performance loss of EGT in MIMO channels, since there is no simple closed-form solution available for the best EGT in MIMO channels. In this study, an EGT design for MIMO channels is proposed and its performance is analyzed theoretically. Interestingly, the SNR loss between the proposed EGT and the MRT in MIMO channels is shown to be at most 1.05 dB as well. Unlike the optimal MRT, which requires both magnitude and phase information of channels, EGT only needs phase information and hence has several implementional advantages compared to the MRT; that is, it can greatly relax the effort of power amplifier and computational complexity. Consequently, simple transceiver design can be realized using the proposed EGT with small performance degradation.