Practical Methods for Wireless Network Coding with Multiple Unicast Transmissions

TL;DR

This paper introduces a practical wireless network coding method for multiple unicast transmissions that leverages distributed encoding, optimal detection, and low-complexity decoding to improve performance and diversity gains.

Contribution

It presents a novel wireless network coding technique using linear block codes, optimal detection rules, and a sum-product decoder, with extensions for enhanced coding gains.

Findings

Near-optimal performance of the SP decoder.

Asymptotic superiority over non-coded methods.

Flexible diversity assignment using greedy codes.

Abstract

We propose a simple yet effective wireless network coding and decoding technique for a multiple unicast network. It utilizes spatial diversity through cooperation between nodes which carry out distributed encoding operations dictated by generator matrices of linear block codes. In order to exemplify the technique, we make use of greedy codes over the binary field and show that the arbitrary diversity orders can be flexibly assigned to nodes. Furthermore, we present the optimal detection rule for the given model that accounts for intermediate node errors and suggest a low-complexity network decoder using the sum-product (SP) algorithm. The proposed SP detector exhibits near optimal performance. We also show asymptotic superiority of network coding over a method that utilizes the wireless channel in a repetitive manner without network coding (NC) and give related rate-diversity trade-off curves. Finally, we extend the given encoding method through selective encoding in order to obtain extra coding gains.