Unraveling the Efficiency of Multi-user Massive MIMO Precoding Techniques in Millimeter Wave Frequency Bands

Millimeter wave (mm-wave) and massive multiple input multiple outputs (MIMO) systems are the two key enabling technologies of 5G and beyond. These technologies use large antennas system within short-range wavelength and high-frequency bands. The mm-wave frequency bands are easily susceptible to path loss and inter-user interference. In this manuscript, the performance of large downlink multiple input multiple output systems using precoding techniques such as maximum ratio transmission (MRT), zero-forcing (ZF), regularized zero-forcing (RZF), dirty paper coding (DPC), lower order truncated polynomial expansion (LTPE) and lower order truncated polynomial expansion-dirty paper coding (LTPE-DPC) are evaluated and compared. The main objectives of linear precoding are to cancel interference between user terminals and mitigate noise amplification, improve spectral efficiency and energy efficiency, and also optimize the transmission of signals from the base station to the user terminals. The simulation results have shown that proposed LTPE-DPC reduces the massive MIMO system's computational complexity and improved the performance like spectral efficiency, energy efficiency and sum rates when compared with the existing precoding techniques at mm-wave frequency bands.