Rate and Outage Performance of Non-Regenerative Two-Way Relaying Protocols with Direct Link

This paper considers a two-way relaying (TWR) half-duplex network in which two users communicate each other with the help of a non-regenerative relay when the direct link between the two users is nonvanishing. For the network, we adopt three protocols each with two, three, or four phases either by using analog network coding (ANC) or amplify-and-forward. The performance of the protocols is analyzed by deriving tight bounds on the average sum rate (ASR) and the outage probability in a unified form. Both results from analysis and simulation show that the three-phase ANC for TWR is favored in the outage performance by trading the time resource with the diversity gain while the two-phase ANC is favored in the ASR performance.