Wireless Broadcast with Physical-Layer Network Coding

TL;DR

This paper analyzes the maximum broadcast throughput in multi-hop wireless networks using physical-layer network coding, establishing bounds and conditions for achievability in various network topologies.

Contribution

It introduces the throughput bounds for half-duplex wireless broadcast networks with PNC and demonstrates their achievability in grid networks.

Findings

Maximum throughput bound is n/(n+1) for single-source broadcast.

The bound is not always achievable in general networks.

The bound is achievable in grid networks.

Abstract

This work investigates the maximum broadcast throughput and its achievability in multi-hop wireless networks with half-duplex node constraint. We allow the use of physical-layer network coding (PNC). Although the use of PNC for unicast has been extensively studied, there has been little prior work on PNC for broadcast. Our specific results are as follows: 1) For single-source broadcast, the theoretical throughput upper bound is n/(n+1), where n is the "min vertex-cut" size of the network. 2) In general, the throughput upper bound is not always achievable. 3) For grid and many other networks, the throughput upper bound n/(n+1) is achievable. Our work can be considered as an attempt to understand the relationship between max-flow and min-cut in half-duplex broadcast networks with cycles (there has been prior work on networks with cycles, but not half-duplex broadcast networks).