Self-Interference-Cancelation-Based SLNR Precoding Design for Full-Duplex Relay-Assisted System

The fifth generation communication systems aim to achieve higher capacity and more user access. Full-duplex (FD) communication can achieve twice the spectral efficiency of the conventional half-duplex systems under ideal conditions, and FD relay is a common application of FD technology. In this paper, we propose a modified signal-to-leakage-and-noise ratio (SLNR) precoding scheme for the FD multiuser MIMO relay system, in which the self-interference (SI) of the relay is considered. In contrast to block diagonalization (BD) precoding and zero-forcing (ZF) precoding, SLNR precoding does not have an antenna dimension limitation, which enables it to support more antennas and users. In addition, SLNR precoding balances the interference and noise of a system, whereas BD precoding and ZF precoding only consider the interference. The numerical results show that the proposed SLNR precoding scheme can achieve better performance with low SI. With a reasonable sum capacity loss, the SLNR precoding scheme provides more user access despite a limited number of transmit antennas.