Coping with Asymmetric Channel Losses in CSMA/CA:Inter-session Network Coding Performance Evaluation and Adaptive Protocol Design

Inspired by the discrepancy between past theoreticalanalysis and real measurements for high-load scenarios for intersessionnetwork coding, we pinpoint and analyze the source ofthis discrepancy in wireless networks implementing a CSMA/CAmedium access scheme. Our analysis shows that CSMA/CA isvery sensitive to asymmetric channel losses caused by channelconditions. Leveraging this analysis, we present an adaptivechannel priority protocol that copes with asymmetric channellosses while being compatible with CSMA/CA. We implementthis protocol and perform real-life measurements that (i) confirmthe sensitivity of the CSMA/CA scheme in real implementations,and (ii) shows that our adaptive protocol provides a simple,yet potent mechanism to cope with asymmetric channel lossesand ultimately to enhance end-to-end throughput in high-loadscenarios