Phase Optimization for Massive IRS-Aided Two-Way Relay Network

In this paper, with the help of an intelligent reflecting surface (IRS), source (S) and destination (D) exchange information through two-way decode-and-forward relay (TW-DFR). We focus on phase optimization IRS to improve system sum rate performance. Firstly, a maximizing receive power (Max-RPS) method is proposed via eigenvalue decomposition (EVD) appreciable enhancement, which called Max-RPS-EVD. To further achieve higher rate, minimum (Max-Min-R) high complexity. reduce its complexity, low-complexity (Max-SR) general iterative (GPI) proposed, Max-SR-GPI. Simulation results show that three methods outperform random method, especially Max-SR-GPI best one achieving at least 20% gain over phase. Additionally, it also proved optimal can be achieved when TW-DFR are located in middle S D.