Energy Efficiency Performance of Millimeter Wave Massive MIMO Systems with Hybrid Precoding

Millimeter wave communication and massive multiple-input multiple-output (MIMO) have emerged as the key enabling technologies for achieving the performance goals of fifth-generation and beyond mobile communication systems. This technology has the ability to remarkably boost the spectral and energy efficiencies of the system utilizing the largely unused millimeter frequency band (30-300 GHz) along with huge multiplexing gain capability realizable with massive number of antennas. Unlike conventional MIMO, fully-digital precoding is infeasible in such systems on account of its huge power consumption, cost and space constraints caused by the RF chains. Hybrid precoding, where signal processing is partitioned into analog and digital domains, has been identified as a promising alternative to fully-digital precoding. This paper presents various precoding/beamforming architectures in MIMO systems. Then, a non-iterative low-complexity hybrid precoding technique suitable for single-user millimeter wave scenarios is presented. The EE performance of millimeter wave massive MIMO systems employing this technique is evaluated and compared with optimal digital precoding and other hybrid precoding techniques. The low-complexity hybrid precoding technique shows promising results in terms of achievable energy efficiency.