Performance evaluation of wireless network coding under practical settings
Ihsan Ayyub Qazi, Pratik Gandhi · Swinburne figshare (Swinburne University of Technology) · 2007
Network coding is a new research area that is likely to have interesting applications in practical networking systems. With network coding, intermediate nodes may send out packets that are linear combinations of previously received information. There are two key benefits of this approach: potential throughput improvements and a high degree of robustness. Traditionally, network coding has been employed in the domain of multicast and broadcast networks. Recently, it has found applications in peer-to-peer and wireless networks. However, the bulk of work on network coding is of theoretical nature and there exists very little experimental work that quantifies the efficacy of this approach in practical environments. In this paper, we evaluate the performance of network coding in a wireless network using test-bed experiments. We use a three node chain topology, where each node is equipped with a 802.11 card. Our results show an average throughput gain of 1.2 with network coding. Our insights reveal that the performance of network coding relies heavily on the presence of bi-directional traffic. If the difference in the upload and download traffic loads is negligible, large number of coding oppurtunities may arise, which results in a significant decline in the average queue size and the packet loss rate. We believe that with carefully designed topologies the gains from network coding could be even more and are likely to be significant enough to motivate deployment in APs.