Multi-Cell Holographic MIMO with Per-RF Chain Power Constraints

This paper investigates the holographic multiple-input multiple-output (HMIMO)-aided multi-cell systems with practical per-radio frequency (RF) chain power constraints. With multiple antennas at both base stations (BSs) and users, we design the baseband digital precoding and the tuning response of metamaterial elements to maximize the weighted sum user rate. We propose an algorithm framework by using block coordinate descent (BCD), weighted minimum mean square error (WMMSE), and maximization-minorization (MM) algorithms. Besides, by exploring the problem structure, the optimal solution of baseband precoding under per-RF chain power constraints is given in a simple closed form at each iteration. Simulation results demonstrate the effectiveness of our algorithms and the advantages of HMIMO architectures.