Transmit beamforming optimization for multiuser MIMO uplink using successive interference cancellation

This paper addresses the transmitter optimization for a multiuser MIMO antenna system in the uplink, which refers to the communication from many mobile stations (XIS) to the base station (BS). The problem of interest is to minimize the total transmit power with users' individual signal-to-interference plus noise ratio (SINR) requirements using successive interference cancellation (SIC) at the BS. In particular, this paper will extend the work by Schubert et al. in [7] to the system where MSs have multiple transmit antennas. For perfect interference cancellation with fixed decoding order, a convergent iterative algorithm is first proposed to optimize the transmit beamforming. A recursive algorithm is further proposed that avoids any matrix inversion to reduce the complexity. Simulation results show that performance of the low-complexity recursive algorithm is comparable to that of the iterative algorithm and both algorithms are near optimal.