Impact of supergain in multi-antenna systems

Wireless systems using multiple antennas can theoretically use array supergain (Uzsoky, M. and Solymar, L., Acta Phys., vol.6, p.185-204, 1956) to exploit the propagation channel optimally. However, this effect has not been observed in traditional multiple-input multiple-output (MIMO) system analysis due to simplifications invoked during the problem formulation. The paper formulates MIMO system capacity when these simplifications are removed, and demonstrates how array supergain impacts the performance under this more complete representation. The framework also allows computation of the capacity when the supergain is constrained to lie below a desired level. Application of the framework to representative examples has quantified the impact of supergain on the achievable MIMO performance.