Bopper : broadcast-based peer-to-peer error recovery for wireless video

Wireless digital video broadcasting has experienced much growth in recent years with industrial systems deployed. In broadcasting, packet loss adversely affects video quality. In this work, we propose and study a novel distributed error recovery scheme on how to repair this loss by means of a broadcast-based secondary channel (using, for examples, Wi-Fi or bluetooth). Our scheme, termed BOP-PER (Broadcast-based Peer-to-Peer Error Recovery), makes use of the broadcast channel to help peers collaboratively recover each other's lost packets. We propose the use of parity packets formed from the source packets received to efficiently recover errors. In order to reduce the energy consumption in the network, we study how to minimize the total number of parities generated (and hence transmitted) while achieving a certain level of recovery capability. We first consider the case with global knowledge (in peer connectivity, loss status on source packets and pairwise loss rates of all peers), and formulate the problem as a linear program which can be solved efficiently. This serves as the optimal performance of the system. We then propose and study a scalable, adaptive and fully distributed algorithm based on local information exchange to recover packet loss. Simulation results show that our distributed algorithm achieves close-to-optimum performance, low control overhead, high recovery capability and fast convergence time