Energy efficiency maximization of massive MIMO systems using RF chain selection and hybrid precoding

Modern day millimeter wave communication systems prefer hybrid precoding architecture over digital architecture due to higher energy efficiency, lower power consumption and comparable spectral efficiency. Both energy efficiency and spectral efficiency defines the system performance of a hybrid precoder and are dependent on the number of available active RF chains. The aim to maximize energy efficiency without any obvious performance degradation in terms of spectral efficiency has created a tradeoff due to dependency of energy and spectral efficiency on RF chains. This tradeoff is being investigated in this paper by performing RF chain selection using evolutionary algorithms. We present a hybrid heuristic approach comprising of low computationally complex evolutionary algorithms for RF chain selection and successive interference cancellation for precoding. Furthermore, we have shown that for low SNR regime the analog percoding is optimal in terms of energy efficiency and for high SNR regime we can adopt the RF chain selection procedure to maximize the energy efficiency. Moreover, the channel irregularities do not effect our proposed scheme.