Co-phasing full-duplex relay link with non-ideal feedback information

We study a wireless full-duplex amplify-and-forward relay link where a destination receives superposition of relayed and direct signals. We propose a new relay protocol that performs co-phasing of the two paths. We analyze the performance of the relay link by calculating closed-form expressions for the average end-to-end signal-to-noise ratio assuming flat Nakagami-m fading channels and by simulating the outage capacity. In the analysis, the phase feedback information is considered non-ideal due to N_ph bit quantization and bit error probability ¿. We show that full-duplex relaying can offer performance improvement over both direct transmission and half-duplex relaying even with few feedback bits and with a feedback channel of relatively low quality.