BER analysis of MIMO ZF receiver with imperfect channel estimation under correlated Rician fading channel

Abstract

Massive MIMO systems operating in spatial multiplexing mode provide greater capacities. Zero Forcing (ZF) is one of the simple detection techniques used in the massive MIMO systems to recover the transmitted data streams at the receiver. In this paper, a generalized expression for the post-detection Signal to Noise Ratio (SNR) of the substream is derived by accounting the spatial correlation and channel estimation error. Further the Average Bit Error Rate (ABER) of ZF receiver for M-Phase Shift Keying (PSK) and M-Quadrature Amplitude Modulation (QAM) is evaluated from the derived post-detection SNR. Also, a closed-form approximation for the ABER of ZF receiver under transmit correlated Rician fading channel with channel estimation error is derived. From the simulation results, it is quite interesting to notice that for equal number of transmitting and receiving antennas and at higher values of average received SNR (Es/N0), the ABER of ZF receiver becomes independent of the receiver correlation. Further, it is also observed that the value of Es/N0 at which the ABER with full spatial correlation converges to the ABER with transmitter correlation varies with respect to the correlation coefficient (ρt,ρr) and Mean Square estimation Error (MSE) (σε2), while keeping the other parameters constant.