Enhancing ZF-DPC Performance with Receiver Processing

Multiuser multiple-input multiple-output (MU-MIMO) systems are known to achieve superior data rates compared to single user (SU-MIMO) systems in the downlink. The achievable rates of MU-MIMO systems are dependent on the precoder design at the transmitter. Dirty paper coding (DPC) is a well known non-linear algorithm to achieve MIMO broadcast channel (BC) capacity. Zero forcing DPC (ZF-DPC) is a sub-optimal way to achieve DPC by triagularizing the channel. In a recent work, it was shown that ZF-DPC with receiver beamforming can provide further improvements. In this paper, we propose an enhancement of ZF-DPC with receiver processing by utilizing the MAC/BC duality. The proposed algorithm is iterative in nature which provides a useful trade-off between complexity and desired performance. Simulation results show that the proposed ZF-DPC algorithm achieves considerable improvement over conventional ZF-DPC and is within 1% of MIMO BC capacity.