Performance Analysis for Practical XOR Two-Way Relay Under Finite Relay Buffer

Network coding is a key technology to improve the spectrum utilization of relay network, however the buffer allocation has not been discussed, and the signalling overhead and the lossy link are often ignored in current researches. In this paper, a practical two-way relay protocol is proposed with the consideration of finite relay buffer, signalling overhead and lossy link. We also construct an analytic model to evaluate the protocol and derive the closed-form expressions of the throughput, queueing delay and overflow probability. Simulation demonstrates that our protocol outperforms the existing transmission strategy, and our analytic model is able to characterise the relay system precisely. Compared with the existing protocol, the throughput of our strategy increases by 14.3 % and the power consumption decreases by 11.3 %. Our mathematical model is useful to configure a suitable buffer size, to gain approximately 16.7 % throughput.