A tale of two prototypes : practical network coding for wireless mesh networks

• Main Author: Hu, Wenjun
• Published: University of Cambridge 2007
• Subjects: 621.382
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.604695

Wireless mesh networks are seen as a cost effective way of providing connectivity for community networks, but their performance under existing approaches is unsatisfactory. In this thesis, we apply network coding, a recent technique from information theory, to wireless mesh networks to improve the network throughput. Various theoretical results have demonstrated the benefits of network coding in many scenarios, but there are few practical systems. In the light of this, we present the prototype design and implementation for two coding protocols, Opportunistic Coding (COPE) and Multipath Code Casting (<i>MC</i>²). The former applies to multiple simultaneous unicast sessions traversing a router, where the use of network coding increases the network capacity, and the latter is for coding within a single unicast flow between a source and destination pair, where coding waives the need for strong coordination between relays on different paths. Both prototypes have been deployed on indoor testbeds, and we study their performance in various traffic and channel conditions. To the best of our knowledge, the prototype for COPE was the first real-world implementation of network coding in a wireless environment, and there was only one other network coding system, for peer-to-peer networks, prior to that. The <i>MC</i>² design integrates multipath forwarding, rate control and error control into a unified framework. Our results show that network coding is a promising technique for the wireless mesh environment, even though challenges remain.