Exploiting Network Coding in Lossy Wireless Networks

Abstract

Users increasingly depend on Wireless LANs (WLANs) for business and entertainment. It is well-known that wireless links are error-prone and require retransmissions to recover from errors and packet losses. Previous work proposed to use network coding (NC) for more efficient MAC-layer retransmissions in WLANs. However, their design is independent from underlying physical layer and MAC capabilities and algorithms. These independent design may result in inefficient utilization of network coding gain, or even impair system performance. This dissertation presents a practical network coding-aided MAC layer retransmission scheme, namely XOR Rescue (XORR). Unlike previous independent network coding design, XORR provides a global approach by integrating the utilization of network coding, adaptation to time-varying wireless channel, fairness, and multi-rate transmission in wireless networks. The main characteristic of XORR is opportunism: each node relies on local information to detect the best transmission/retransmission and exploits the benefits provided by both network coding and multiuser diversity whenever they arise. The