Throughput performance of wireless networks can be enhanced by applying network coding NC technique based on opportunistic listening. The packets sent or overheard by a network node should be locally cached for the purpose of possible future decoding. How to manage the cache to reduce the overhead incurred in performing NC and, meanwhile, exploit performance gain is an interesting issue that has not been deeply investigated. In this paper, we present a framework for packet caching policy in multihop wireless networks, aiming at improving decoding efficiency, and thus throughput gain of NC. We formulate the caching policy design as an optimization problem for maximizing decoding utility and derive a set of optimization rules. We propose a distributed network coding caching policy NCP, which can be readily incorporated into various existing NC architectures to improve NC performance gain. We theoretically analyze the performance improvement of NCP over completely opportunistic NC COPE. In addition, we use simulation experiments based on ns-2 to evaluate the performance of NCP. Numerical results validate our analytical model and show that NCP can effectively improve the performance gain of NC compared with COPE. Copyright © 2013 John Wiley & Sons, Ltd.
['Qinglong Liu', 'Gang Feng']
A framework of data caching for improving decoding efficiency of opportunistic network coding