Efficient Packet Recovery Using Prioritized Network Coding in DVB-IPDC Systems

The DVB-H standard is proposed to disseminate videos to mobile devices. However, packet loss is inevitable due to the broadcasting nature. To deal with this issue, DVB-IPDC suggests incorporating another wireless network for data retransmission. This paper takes a WiMAX network as an example in DVB-IPDC and models its channel as repetitive frames. During each frame, mobile devices sends their recovery requests of lost packets to a WiMAX base station and the base station adopts network coding to broadcast these packets. This paper then formulates a prioritized network coding (PNC) problem that asks how the base station uses at most \LoR coded packets in each frame such that it can recover the maximum aggregate number of lost packets while minimize the aggregate number of packets discarded due to out of deadlines. We develop a solution using XOR coding, which constructs a weighted bipartite graph to calculate the benefit to broadcast each coded packet. Then, the solution tries to maximize the overall benefit by finding a maximum-weighted \LoR dominating set. The contribution of this paper is to propose a new PNC problem in DVB-IPDC systems and develop an efficient PNC solution.