Energy Efficient Hybrid Precoding for Millimeter Wave F-RAN with Wireless Fronthaul

Millimeter wave (mmWave) communication emerges as an enabling technology for Gbps transmission. A further performance enhancement can be achieved by incorporating mmWave communication into fog radio access networks (F-RANs), which alleviate the large path loss of mmWave signals by shortening the distance between transmitters and users and reduce the latency by caching at enhanced remote radio heads (eRRHs). The full benefit of mmWave F-RANs is leveraged on a joint design of signal processing at the centralized baseband unit (BBU) and distributed eRRHs. In this paper, we propose an energy efficient hybrid precoding design for the downlink mmWave F- RANs with wireless fronthaul links, where digital and hybrid precoders are exploited at the BBU and eRRHs, respectively. We develop an effective method to solve the resulting difficult precoding optimization problem and provide numerical results to demonstrate the effectiveness of the proposed mmWave F-RAN design.