Comments on "Performance of Two-Way Opportunistic Relaying With Analog Network Coding Over Nakagami-m Fading"

The following paper is a comment on the paper titled "Performance of Two-Way Opportunistic Relaying With Analog Network Coding Over Nakagami-m Fading". In the original paper, the authors investigated the performance of the outage-optimal two-way opportunistic relaying scheme with analog network coding over independent but not identically distributed Nakagami-m fading channels. For the relay-selection process, the authors declared that the two distributed methods, given by eqs. (6) and (7) in the original paper, were equivalent. According to Kun Xu and Yuanyuan Gao, the equivalence of the two criteria cannot be guaranteed, even for the high-signal-to-noise ratio (SNR) regime.