Network Coding in IEEE 802.11 Wireless LANs with an Enhanced Channel Access Scheme

In this paper, we present a set of simple extensions to the IEEE 802.11 MAC that allow the efficient realization of wireless network coding. The main characteristic of the proposed protocol is that it improves the efficiency of packet coding decisions and allows verifying the decodability of packets before they are transmitted over the network. The previous goals are achieved by adopting two techniques. First, we introduce the concept of opportunistic acknowledgments (OACKs), and second, we adopt the use of virtual buffers that are used for selectively storing overheard packets by a particular node. We performed extensive simulations for several ad hoc network topologies that test the proposed protocol. Our results indicate that significant throughput enhancements can be achieved when compared with network coding schemes that are realized with the legacy 802.11 MAC.