Opportunistic MIMO Two-Way Relaying: Diversity-Multiplexing Tradeoff Analysis

This letter analyzes the diversity-multiplexing tradeoff (DMT) performance of an opportunistic MIMO two-way relaying (OMTWR) scheme for the time-division broadcast (TDBC) and multiple-access broadcast (MABC) protocols. The analysis reveals the following. In terms of the DMT, the MABC-based OMTWR outperforms its TDBC-based counterpart for low multiplexing gains. Interestingly, the opposite is found to be true in the high-multiplexing gain regime. In terms of the outage capacity, the MABC-based OMTWR outperforms the TDBC-based scheme in the low-SNR regime, whereas, in the high-SNR regime, the TDBC-based OMTWR achieves higher transmission rate compared with its MABC-based counterpart.