Scheduling for Massive MIMO with Few Excess Antennas

Scheduling all user equipment jointly and using a linear precoder is optimal for massive MIMO with a very large number of base station antennas. Scheduling becomes more important as the number of base station antennas is reduced. We determine the regime where scheduling provides gains for massive MIMO scenarios with linear precoding methods. We apply semi-orthogonal user selection to massive MIMO and propose a scheduling algorithm with smaller complexity.