We propose a new architecture for wireless mesh networks. In addition to forwarding packets, routers mix (i.e., code) packets from different sources to increase the information content of each transmission. We show that intelligently mixing packets increases network throughput. Our design is rooted in the theory of network coding. In contrast to prior work on network coding, which is mainly theoretical and focuses on multicast traffic, ours is practical and solves the common case of unicast traffic. We present the first implementation of network coding in a wireless network. Our system introduces a coding layer between the IP and MAC layers. It works with UDP and TCP traffic, and hence seamlessly integrates with existing applications. We evaluate our design on a 34-node wireless testbed and show that it delivers a 3-4x increase in the throughput of wireless mesh networks.
