Random beamforming for multiuser multiplexing in downlink correlated Rician channel

Multiuser multiplexing is an attractive research topic for wireless communication system, since it can increase the sum channel capacity dramatically. The multiuser multiplexing is realized based on the independent channel influences of different users. However, the multiplexing gain will be reduced, when the channels are correlated among different users, due to the destroyed independent statistics. This paper proposes a scheme that employs random beamforming (RBF), which is the evolution of opportunistic beamforming (OBF), to achieve multiuser multiplexing for correlated Rician channel. According to the feedback of the channel state information (CSI), the user with the largest signal-to-interference and noise ratio (SINR) is selected to transmit data, similarly to that of the traditional OBF system. Numerical analysis shows that the RBF technology is capable of boosting the performance of system capacity for correlated Rician channel, when the number of users is large enough.