Coping with asymmetric losses in CSMA/CA: Inter-session network coding performance evaluation and adaptive protocol design

Inspired by the discrepancy between past theoretical analysis and real measurements for high-load scenarios for inter-session network coding, we pinpoint and analyze the source of this discrepancy in wireless networks implementing a CSMA/CA medium access scheme. Our analysis shows that CSMA/CA is very sensitive to asymmetric channel losses caused by channel conditions. Leveraging this analysis, we present an adaptive channel priority protocol that copes with asymmetric channel losses while being compatible with CSMA/CA. We implement this protocol and perform real-life measurements that (i) confirm the 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 losses and ultimately to enhance end-to-end throughput in high-load scenarios.