Law of large numbers analysis of antenna selection aided downlink beamforming in massive MISO under RF chains constraint

Massive MIMO has potential to offer massive throughputs by mounting a large number of antennas at the base station. One of the major limitations of massive MIMO is the cost of a huge number of RF chains. Antenna Selection is a promising signal processing technique which reduces the number of required RF chains while keeping the system's performance at a certain minimum level. In this paper, we investigate the capacity performance of an antenna selection scheme employed in a massive MISO system. The main contribution of this paper is a theorem which provides a concise formula for the limiting normalized channel power gain in the considered scheme. The deterministic equivalent of the normalized channel power gain is valid in the regime when the number of RF chains, Nc, and the number of base station antennas, NT, tend to infinity while maintaining fixed ratio β = Nc/NT. Numerical experiments suggest that the deterministic equivalents are accurate even for relatively small Nc, NT.