LocalTree: An Efficient Algorithm for Mobile Peer-to-Peer Live Streaming

To provide live streaming service to mobile users, traditionally each user pulls content from a server over his cellular network. In order to overcome the scalability problem of last-hop bandwidth bottleneck, mobile peer-to-peer (P2P) streaming can be used where mobile devices relay their stream received in a multi-hop manner by means of a secondary channel (such as Wi-Fi or bluetooth). We investigate the design of distributed algorithm termed LocalTree, which minimizes the number of broadcasters while meeting a certain video quality requirement under peer churns. We first formulate the problem and show that it is NP-hard, and hence propose LocalTree which achieves robustness similar to an unstructured mesh and low delay similar to a global tree. Simulation results show that LocalTree outperforms other algorithms substantially in terms of number of broadcasters used (by as much as 50%).