SlideOR: Online Opportunistic Network Coding in Wireless Mesh Networks

Opportunistic routing significantly increases unicast throughput in wireless mesh networks by effectively utilizing the wireless broadcast medium. With network coding, opportunistic routing can be implemented in a simple and practical way without resorting to a complicated scheduling protocol. Traditionally, due to the constraints of computational complexity, a protocol utilizing network coding needs to partition the data into multiple segments and encode only packets in the same segment. However, it is extremely challenging to decide the optimal time to move to the transmissions of the next segment, and existing designs all resort to different heuristic ideas that might harm network throughput. To address this problem, we propose SlideOR, a new protocol to encode source packets in overlapping sliding windows such that coded packets from one window position may be useful towards decoding the source packets inside another window position. Through extensive simulations, we show that SlideOR outperforms the existing solutions and is amenable to much simpler implementation than solutions with complicated scheduling among multiple segments.