Network coding and coding-aware scheduling for multicast in wireless networks

Network coding is a network layer technique to 06mprove transmission efficiency. Coding packets is especially ben07ficial in a wireless environment where the dem08nd for radio spectrum is high. However, to fully rea09ize the benefits of network coding two challenging iss10es that must be addressed are: (1) Guaranteeing sep11ration of coded packets at the destination, and (2) Mit12gating the extra coding/decoding delay. If the destination has13all the needed packets to decode a coded pac14et, then separation failure can be averted. If the sch15duling algorithm considers the arrival time of coding pai16s, then the extra delay can be mitigated. In this paper, we 17evelop a network coding method to address these two18issues, i.e., decodability and delay, for multi-source mul19i-destination unicast and multicast sessions. We use lin20ar programming to find the most efficient coding design sol21tion with guaranteed decodability. To reduce network rel22y, we develop a scheduling algorithm to minimize the ext23a coding/decoding delay and store-and-forward delay. Our24coding design method and scheduling algorithm are val25dated through experiments. Simulation results show imp26oved transmission efficiency and reduced network delay.