A Novel Discrete Phase RIS-Aided MIMO Multiuser Transceiver Design Using Dirty Paper Coding

In this letter we present a novel transceiver design for RIS-aided MIMO multiuser downlink communications. The design employs dirty paper coding and practical discrete-phase RIS to overcome the limitations of existing techniques and achieve the ultimate channel sum-rate capacity. The new design supports arbitrary number of antennas and users and provides a practical solution for next-generation wireless networks. In particular, a new method is proposed for optimizing the discrete phase shifts of RIS, with polynomial complexity in the number of RIS elements and linear complexity relative to the number discrete phases. Simulations show that our design with QPSK-phase RIS offers a cost-effective solution with significant performance improvement upon existing works for RIS-aided MIMO communications.