Joint Relay-and-Antenna Selection for Two-Way Decode-and-Forward MIMO Relay Networks

In this paper, two novel joint relay-and-antenna strategies are proposed and analyzed for multi-relay two-way multiple-input multiple-output (MIMO) decode-forward (DF) networks, namely, joint OR-TAS(Opportunistic Relaying Transmit Antenna Selection) and joint SC-TAS (Selection Cooperation-Transmit Antenna Selection). For each joint selection scheme, the best transmit antenna at the two sources, a best relay, and a single best antenna at the selected relay are jointly determined in an optimum sense. The performance of these strategies is quantified by deriving the overall outage probability. For OR-TAS, we derive its outage probability directly, while for SC-TAS, we obtain its outage probability by proving that it is identical to that of OR-TAS. Also, the diversity orders is derived by presenting the upper bound and the lower bound of the overall outage probability, and the results show that the proposed selection strategies achieve the full diversity order. Finally, simulations are given to verify the correctness of the theoretical analysis.