Abstract: A multi-objective optimized active and passive beam assignment algorithm based on energy efficiency (EE) and spectral efficiency (SE) trade-offs is proposed for the problem of low rank-induced MIMO multiplexing gain degradation in distributed intelligent reflecting surface (IRS)-assisted millimeter wave MIMO systems. First, a multi-objective optimization framework for EE and SE is developed using the linear weighting method. Secondly, the alternating optimization (AO) algorithm is used to jointly optimize active beamforming (ABF) and passive beamforming (PBF). Finally, the semi-positive definite relaxation algorithm (SDR) is used to solve the non-convex unit mode constraint problem of IRS. Simulation results show that the algorithm can flexibly adjust the trade-off coefficient according to the actual communication service to achieve the balance between EE and SE, and effectively improve the communication performance of millimeter wave MIMO system (mm Wave MIMO).

Key words: millimeter wave multiple-input multiple-output, intelligent reflecting surface, beam forming, energy efficiency, spectral efficiency