Buffer Management for Wireless Media Streaming

We study playout buffer management at the receiver for supporting multimedia streaming services over unreliable wireless links. On one hand, memory is a precious resource on portable wireless devices and must be used judiciously. On the other hand, allocating a big playout buffer to a media streaming application reduces the probability of a playout interruption/freeze due to buffer underflow, thus improving the user´s perceived experience. Thus, inherent in the wireless media streaming scenario is a tradeoff between memory utilization and quality-of-service (QoS) delivered to the application layer. We study this buffer vs. QoS tradeoff in a dynamic programming (DP) framework. Within the same setting, we also address the issue of determining the optimal rebuffering level when the buffer underflows. Leveraging closed form solutions obtained for a special case of our formulation, we propose BuM, a very low complexity heuristic dynamic buffer management algorithm. The near optimality of BuM, as demonstrated by experimental results, in conjunction with its ease of implementation, makes it an attractive option from a practical perspective.