Relay selection with network coding in twoway relay channels

Abstract—In this paper, we consider the design of joint network coding (NC) and relay selection (RS) in two-way relay channels. In the proposed schemes, two users first sequentially broadcast their respective information to all the relays. We propose two RS schemes: 1) a single RS with NC and 2) a dual RS with NC. For both schemes, the selected relays perform NC on the received signals sent from the two users and forward them to both users. The proposed schemes are analyzed, and the exact bit-error-rate (BER) expressions are derived and verified through Monte Carlo simulations. It is shown that the dual RS with NC outperforms other considered RS schemes in two-way relay channels. The results also reveal that the proposed RS–NC schemes provide a selection gain compared with an NC scheme with no RS and an NC gain relative to a conventional RS scheme with no NC. Index Terms—Bidirectional relay, cooperative communications, decode and forward (DAF), network coding (NC), relay networks, selective relaying, two-way relay channels. I