Zero-forcing hybrid precoding based on QR-decomposition in millimeter wave systems

摘要

Millimeter Wave system has attracted much attention because it provides more spectrum resource to offer considerable capacity improvement and supports massive multiple-input multiple-output (MIMO) by its shorter wave length. In traditional precoding methods, the signal is processed digitally at baseband. However, the large number of RF chains cause high hardware cost and power consumption in mmWave systems. Hybrid precoding, which uses both analog processing in the RF domain and digital processing in the baseband, is an alternative to reduce the number of RF chains and control the cost. In this paper, transmit precoding in mmWave systems with hybrid architecture and large antenna arrays is considered. A zero-forcing hybrid precoding algorithm based on QR-decomposition for mmWave system is proposed. According to the matrices obtained based on the QR-decomposition of the ZF matrix, OMP is used to design analog processing matrix at RF domain and digital processing matrix at baseband. Numerical results are presented on the performance of spectral efficiency and show that the performance of the proposed hybrid method is close to that of the full digital ZF precoding algorithm with less RF chains used in mmWave systems.