CEO: Consistency of Encoding and Overhearing in Network Coding-Aware Routing

Network coding-aware routing attempts to find coding opportunities between an incoming flow and existing flows in wireless ad hoc networks. However, we find that a problem of most proposed coding-aware routing schemes is that they may misidentify the coding opportunities. Specifically, the opportunity misidentification may appear when a packet is about to be re-encoded. We call this the re-encoding problem. To solve this problem, we propose a principle called consistency of encoding and overhearing (CEO). By adhering to CEO, the encoding node is able to avoid misidentifying coding opportunities, thus ensuring the successful decoding of all encoded packets. In this letter, we first show the importance of CEO by analysis in a simple topology. Then, we introduce a distributed way to apply CEO to a coding-aware routing scheme, and show the improved network performance with CEO by simulation in different scenarios.