Physical-Layer Network Coding Based Throughput-Optimal Transmission for Bidirectional Traffic

Abstract

In this study, we develop a physical-layer network coding based throughput-optimal transmission scheduling policy, which we call network coding aware maximum differential backlog (NCMDB), and demonstrate its throughput optimality. As the proposed policy requires an NP-hard network-wide centralized algorithm to determine the optimal transmission schedule, we propose a distributed NCMDB based on link prioritization (D-NCMDB) as a lower bound approach. We further propose a bidirectionality-aware route establishment scheme for the best application of the NCMDB and D-NCMDB policies. Simulations confirm that compared to the signal-to-interference-based interference avoidance transmission approach and random maximal physical-layer network coding approach, the proposed D-NCMDB scheme offers $48\%$ and $27\%$ increased throughput, $78\%$ and $63\%$ reduced access delay, and $80\%$ and $20\%$ enlarged stability, respectively. The proposed distributed transmission scheduling scheme can be employed in future communication networks in which both the number of nodes and the amount of interference increase exponentially.