Hybrid analog-digital precoding for millimeter wave MIMO systems

Traditional all-digital precoder due to the huge hardware cost of the RF chain, making it no longer suitable for mmWave large-scale MIMO systems, hybrid analog/digital precoding is proposed to reduce the hardware cost of RF components while achieving similar performance to all-digital precoder. This paper presents a TOMP hybrid precoding algorithm. In the algorithm, the optimal all-digital precoding matrix is obtained by singular value decomposition of the channel matrix. Using the designed initial matrix as the RF precoding initial value, update the RF matrix by OMP idea, and then defining algorithm end conditions, using iterative improvements to improve the performance of hybrid precoders. In addition, the influence of different precoding schemes on energy efficiency performance is analyzed from two aspects: signal-to-noise ratio and radio frequency chain number. The simulation results show that the TOMP algorithm appears to provide high performance than the OMP algorithm and close to the optimal all-digital precoding scheme. Energy efficiency analysis results show that it is more appropriate to adopt a hybrid precoding scheme to guarantee both spectral efficiency and energy efficiency.