Location information Aided Massive-MIMO Beam Domain Precoding for Next Generation Railway Mobile Communications

In massive multiple-input multiple-output (massive MIMO) systems, the number of antennas at transmitter is large, the calculation of precoding becomes complex. At the same time, a dynamic precoding scheme is needed when the mobile station (MS) is moving. In this paper, we propose a simplified precoding scheme based on the concept of beam domain and an adaptive allocation scheme for next generation railway mobile communications. First, we reduce the dimension of the channel in the beam domain, simplify the precoding calculation. Then, the beam set is adjusted according to the position information during the MS movement, so that the beam set with the highest gain is allocated to the MS. Finally, the feasibility of this scheme is verified by simulation.