Log-likelihood ratio-based relay selection algorithm in two-way relay channel with physical network coding

Relay selection and network coding are two main factors for improving cooperative Networks. Employing all the relays without any relay selection in the network increase power consumption and cost to transfer data. Selection of one or more relays decreases the power consumption, reduces the interference and complexity. Network coding increase throughput and decrease error rate. This research proposes a new method for relay selection in two-way relay channel with considering network coding. This choice is based on absolute value of the log-likelihood ratio(LLR) of the received signal at each relay node. The proposed scheme is derived for BPSK modulation. System performance is evaluated by numerical simulations and compared with Max-Min relay selection method. The proposed method is evaluated by bit error rate (BER) simulated curves for AWGN channels and compared to Max-Min relay selection method.