On analysis of two-way relaying with network-coded ARQ

In this work, we study the throughput of two-way relay channel (TWRC) with different automatic repeat-request (ARQ) strategies. Beyond orthogonal relaying, we propose two network-coded ARQ schemes, where the packets intended for different end terminals could be combined at the relay nodes. By considering the per-hop and end-to-end maximum number of transmissions constraint, we derive the closed-from throughput expression. We demonstrate that network coding can greatly improve the system throughput, but the throughput gain is upper bounded. Besides, we come up with a near-optimum power allocation scheme to maximize the throughput. Compared to equal power allocation, the proposed power allocation scheme can greatly improve the throughput especially when the network topology is highly asymmetric.