Crosslayer design for distributed MAC and network coding in wireless ad hoc networks

In this paper, we address the joint design and distributed implementation of medium access control (MAC) and network coding in wireless ad hoc networks. We consider a slotted wireless network with links modeled as classical collision channels. We assume omnidirectional packet transmissions and do not allow simultaneous transmission and reception by any node. These wireless network properties demand a new formulation of time-varying network coding with additional constraints that reflect the strong interactions with the underlying MAC operation. First, we outline how to construct network coding over a predetermined set of wireless network realizations with conflict-free transmission schedules. The wireless network realizations are separately activated using a time division mechanism and the network flows are chosen to optimize the performance measures (such as stable throughput or average energy costs) through wireless network coding. Next, we follow an alternative approach of joint wireless network coding and link scheduling with a distributed implementation. The analysis is based on decomposing wireless networks into subtrees and applying graph coloring on the simplified subtree network representations to derive the wireless network codes that are further converted to the conflict-free sets of transmission schedules. Finally, we extend network coding to operate with arbitrary single-receiver MAC protocols within each receiver´s area