Optimizing Segment Caching for Mobile Peer-to-Peer Interactive Streaming

With the penetration of broadband wireless access network and devices, interactive multimedia streaming to handhelds has become a reality. However, it is still challenging to offer such services to a large number of users in a cost-effective manner. With the increase of battery lifetime, memory capacity and processing capability, and the fact that many mobile devices nowadays are equipped with multiple interfaces (3G, Wi-Fi, bluetooth, etc.), we study wireless peer-to-peer (P2P) streaming for scalable interactive streaming. In the network, videos are divided into segments and collaboratively cached and accessed among mobile devices. The major challenge is then which segment to cache at each mobile to achieve efficient access (in terms of low segment access cost). We first formulate the problem of segment caching to minimize segment access cost. We show that the optimization problem is NP-hard and present OPSEC (Optimized Segment Caching), a distributed algorithm which achieves collaborative and efficient segment caching, given heterogeneous caching capacities of the participating users. Using simulation, we show that OPSEC achieves much lower network access cost as compared with some recent schemes for interactive wireless video streaming.