Network Coding-Aware Fair Opportunistic Scheduling in Lossy Wireless Networks

Users increasingly depend on WLAN for business and entertainment. It is well-recognized that wireless links are prone to errors. Previous work, ER, proposed to use network coding (NC) for providing more ef cient MAC-layer retransmission scheme in WLAN. However, it uses inef cient and costly reception report scheme and does not consider the effect of heterogenous and time-varying wireless conditions and fairness. These issues are critical for getting full bene ts of network coding. We show that, without addressing them, NC may even cause negative effect on the system. In this paper, we present a novel MAC-layer retransmission scheme, namely XORR, which uses reception estimation without extra overhead and adopts NC-aware opportunistic scheduling with maintaining temporal fairness in WLAN. We prove our NC-aware scheduling algorithm is fair and it will always improve the expected goodput for each wireless clients. We further verify XORR with extensive simulation as well as experiment studies and nd that our scheme outperforms traditional opportunistic scheduling (without NC) and 802.11 about 25% and 40%, respectively.