Low-Complexity Sum-Capacity Maximization for Intelligent Reflecting Surface-Aided MIMO Systems

Reducing computational complexity is crucial in optimizing the phase shifts of Intelligent Reflecting Surface (IRS) systems since IRS-assisted communication are generally deployed with a large number reflecting elements (REs). This letter proposes low-complexity algorithm, designated as Dimension-wise Sinusoidal Maximization (DSM), to obtain optimal IRS that maximizes sum capacity MIMO network. The algorithm exploits fact objective function for optimization problem sinusoidal w.r.t. shift each RE. numerical results show DSM achieves near maximal sum-rate and faster convergence speed than two other benchmark methods.