Abstract-We consider energy efficient network coding design in wireless networks with multiple unicast sessions. Our approach decomposes multiple unicast sessions into a superposition of multicast and unicast sessions, with coding occurring only within each session. We give an optimization approach that is more general than the existing poison-remedy optimization formulation. For the case of wireless, we consider XOR coding and give an achievable rate region for a primary interference model. To simplify network operation, we give an oblivious backpressure algorithm which does not optimize overhearing of transmissions, and a practical protocol called COPR based on the oblivious backpressure algorithm. Simulation experiments show that COPR largely reduces network power consumption over existing algorithms. In this paper, we consider energy efficient cross-layer optimization for wireless networks by exploiting network coding and multiple-reception gain. We focus on network coding across multiple unicast sessions, or intersession network coding. Optimal intersession network coding design is an open problem; various suboptimal algorithms have been proposed, e.g. Our approach decomposes multiple unicast sessions into a superposition of multicast and unicast sessions, with coding occurring only within each session. For the case of wireless networks, we consider simple one-hop XOR coding as in COPE [1] , where each node uses knowledge of what its neighbors have overheard to perform opportunistic network coding such that each encoded packet can be decoded immediately at the next hop. Reference [1] demonstrated substantial throughput gains for network coding that grow with the level of congestion. In this paper we consider the benefit of network coding for energy saving in power-constrained settings with less congestion. In doing so we develop general techniques that apply also to the case of throughput optimization and congestion control in wireless networks. To exploit multiple-reception gain, we model the network as a directed hypergraph. The achievable rate region of one-hop XOR coding is determined under a primary interference model. It is difficult and complicated to design dynamic scheduling and coding algorithms to achieve the entire rate region as it typically requires optimization over overheard flows. To simplify network operation, an oblivious backpressure algorithm is proposed which does not optimize overheard flows. The link scheduling problem is found to be a maximum weighted hypergraph matching problem, which can be solved distributedly by
Energy-efficient opportunistic intersession network coding over wireless is proposed in REF , following a node-based NUM formulation and its solution based on backpressure.
Energy Efficient Opportunistic Network Coding for Wireless Networks
IEEE INFOCOM 2008 - The 27th Conference on Computer Communications
IEEE INFOCOM 2008 - The 27th Conference on Computer Communications
Computer Science