Correlated MIMO Rayleigh fading systems with transmit channel state information

We analyze the capacity of correlated multiple-input-multiple-output (MIMO) channels when channel state information (CSI) is available at both the transmitter and the receiver. We show that the achievable rate by using simple beamforming can approach this capacity when the MIMO channels are highly correlated. To simplify the coding/decoding and power adaption, we apply truncated channel inversion (TCI) in MIMO correlated channels and evaluate the achievable rates. The results show that in highly correlated MIMO fading channels, beamforming combined with TCI can get close to capacity. This provides a simplified near optimum coding, as beamforming with TCI requires only one code designed for the AWGN channel and one coder/decoder pair.