Uplink block diagonalization for massive MIMO-OFDM systems with distributed antennas

In this paper, we propose a block diagonalization (BD) procedure for the uplink of massive MIMO-OFDM systems to decompose the received signal vector, at the base station (BS), into independent single-user MIMO-OFDM signals. After uplink BD, the detection procedure can be performed separately for each active user, thus reducing the computational complexity when compared with standard detection techniques, where all the active users are coupled. In the proposed scheme, unlike prior work in which downlink BD algorithms are used, it is not necessary to use any precoding at the transmit side. The performance of the proposed scheme is evaluated in a realistic mobile radio channel for an indoor (local area) scenario with distributed antennas at the BS.