Computationally Efficient Relay Antenna Selection for AF MIMO Two-Way Relay Channels

This correspondence develops a computationally efficient scheme to select a subset of relay antennas to maximize the achievable sum rate (ASR) of amplify-and-forward multiple-input multiple-output two-way relay channels. To reduce the computational complexity of antenna selection (AS), two sequential AS algorithms, joint AS (JAS) and separate AS (SAS), are proposed. JAS jointly selects a pair of receive-transmit antennas at each sequential step. In contrast, SAS separates receive and transmit AS into a two-stage algorithm; the receive antenna set is selected first, followed by selection of the transmit antennas. Simulation results show that the proposed algorithms achieve nearly the same ASR as compared to an exhaustive search, but with significantly reduced computational complexity.