Beam-domain full-duplex transmission in massive MIMO system

In this paper, we consider beam-domain full-duplex (FD) transmission in massive multiple-input multiple-output (MIMO) system. By exploiting the channel spatial sparsity, massive MIMO channel is compressed in the beam-domain under certain selected basis spaces and as a result the channel dimension required to be estimated can be greatly reduced. According to the distribution of effective beams of uplink/downlink channel and self-interference (SI) channel, all the users are scheduled into several uplink and downlink groups. With the estimated effective beam-domain channel, we design the uplink and downlink beamforming matrices at the base station to suppress the SI, inter-user interference and inter-group interference. The achievable sum-rate of the proposed beam-domain FD massive MIMO transmission scheme is analyzed and the joint user and BS power allocation scheme is proposed to optimize the system achievable sum-rate. Simulation results show that the proposed beam-domain FD transmission scheme outperforms existing time division duplex (TDD) and frequency division duplex (FDD) massive MIMO and FD massive MIMO transmissions schemes on the spectral efficiency performance.