Investigation on Hybrid Precoding for Multi-user MIMO Systems

Millimeter waves (mmWave) are used in wireless communication to overcome the spectrum crunch. Beamforming waves are used to reduce the pathloss inherent to mmWaves and it is achieved by using large antenna arrays. Conventional digital beamforming involves complexity of large antenna arrays besides increased cost of the system, while analog beamforming can handle only single data signal at a time. Therefore hybrid precoding method gives a promising solution. In this investigation, a hybrid precoding model is designed and verified only for the transmitter. Then individual hybrid precoding models are implemented by applying Kalman, Minimum Mean Square Error (MMSE) and Zero-Forcing precoding (ZF) algorithms at baseband precoder. Also, a digital system is implemented using MMSE baseband precoder. The results of all the hybrid precoding models are compared with digital precoding model to identify a hybrid model which gives better performance in terms of spectral efficiency and Signal to Noise Ratio (SNR).