Network Coding as a WiMAX Link Reliability Mechanism

We design and implement a network-coding-enabled reliability architecture for next generation wireless networks. Our network coding (NC) architecture uses a flexible thread-based design, with each encoder-decoder instance applying systematic intra-session random linear network coding as a packet erasure code at the IP layer. Using GENI WiMAX platforms, a series of point-to-point transmission experiments were conducted to compare the performance of the NC architecture to that of the Automatic Repeated reQuest (ARQ) and Hybrid ARQ (HARQ) mechanisms. In our scenarios, the proposed architecture is able to decrease packet loss from around 11-32% to nearly 0%; compared to HARQ and joint HARQ/ARQ mechanisms, the NC architecture offers up to 5.9 times gain in throughput and 5.5 times reduction in end-to-end file transfer delay. By establishing NC as a potential substitute for HARQ/ARQ, our experiments offer important insights into cross-layer designs of next generation wireless networks.