QOS-Based Antenna and User Selection in Large-Scale Fading for Massive-MIMO Systems

This paper considers a zero-forcing (ZF) downlink transmission in a multiuser massive-MIMO system under large-scale fading. While the base station has many antennas, the associated circuit costs require some antennas to be turned off. Further, the users have quality of service (QoS) constraints and cannot be served with arbitrarily low signal-to-interference-plus-noise ratios. Instead, the base stations seeks to schedule only a subset of users for which the QoS constraints can be met, while the remaining users must be scheduled in other time-frequency slots. A joint antenna selection, power allocation, and user selection problem is formulated. Different from the existing approaches that either rely on greedy schemes or other heuristics, an efficient algorithm is proposed that yields the globally optimum solution to the problem. Finally, the simulation results are presented to corroborate the efficacy of the proposed schemes.