A Hybrid Precoding Algorithm Based on Intelligent Search in Millimeter Wave Massive MIMO Systems

In order to solve the problem of high hardware cost and difficult implementation in traditional fully connected millimeter wave massive MIMO systems, a partially connected hybrid precoding scheme based on intelligent search algorithm is proposed. In this algorithm, the classical zero-forcing digital precoding scheme is used at the base station, and the analog precoding matrix is designed separately in the part of analog precoding, which avoids the high complexity of the joint design of the digital and analog precoding matrix. After that, the block diagonalization property of analog precoding matrix is made use of to transfer the problem of designing analog precoding matrix to the problem of optimization, which is to be solved by Satin Bowerbird Optimization. Aiming at making up the shortcoming of original SBO in searching global optimum, an algorithm called DSBO is proposed. In the case that phase shifters’ resolution is limited, DSBO is improved to solve this discrete optimization problem. The simulation results show that the scheme proposed presents competitive system capacity as well as a relatively low bit error rate, and is able to handle the case that phase shifters’ resolution is limited.