Digital beamforming algorithm for 5G low-SHF-band massive MIMO with intersite coordination

Massive multiple-input multiple-output (Massive MIMO) beamforming (BF) is an important technology to utilize higher frequency bands effectively. Fully-digital Massive MIMO BF can be applied for low-SHF-band, and joint processing of digital fixed BF and channel state information (CSI)-based precoding (Digital FBCP) is proposed as one of the fully-digital algorithms. Additionally, it is assumed that multiple sites with low-SHF-band cover continuous areas in the early fifth-generation (5G) mobile communication system. New BF algorithm for multi-site Massive MIMO is required to enable to transmit effectively multiple streams with intersite interference reduction. In this paper, we propose three types of Digital FBCP algorithm with intersite coordination. Throughput performances are shown by link level simulation, and we clarify that the proposed schemes can improve throughput performance compared to that without intersite coordination.