Performance analysis of two-way relay systems based on partial channel state information

In two-way amplify-and-forward relay communication systems with two multiple-antennas sources, two sources utilize partial channel state information (CSI) due to feedback delay to design transmit beamforming vectors, respectively. The effect of feedback delay on system performance is investigated, and the semi-analytical expressions of system outage probability and average symbol error rate are derived over Rayleigh fading channels. Simulation results show that, the increase of antenna number will improve the system performance, while the increase of feedback delay will degrades the system performance, and when there is feedback delay there is no diversity gain, i.e., diversity order equals to 1, even for a small feedback delay. Numerical simulations coincide with semi-analytical results verifies the accuracy of the analysis conclusions.