关键词: 网络编码, P2P流媒体, 动态段粒度

Abstract: It has been proved that network coding technology can improve the overall performance of P2P streaming systems. However, the existing systems all use fixed segment granularity coding scheme for data dissemination. To overcome the limitations of fixed segment granularity coding scheme, and fit for the stochastic characteristic of real networks, this paper proposes the new concept of dynamic segment granularity, with which the peers can tune the segment granularity dynamically while encoding. Then this paper answers three questions about how to implement dynamic segment granularity, which are the coding modes, segment granularity range and output performance. Finally this paper designs a new coding scheme with dynamic segment granularity. According to the playing buffer states and the service capabilities of source peers, this scheme can tune the segment granularity of coded blocks dynamically. The experiments illustrate that this scheme can offer better QoS with network jitters or peer churns. It is believed that dynamic segment granularity shares a new idea of further improving the QoS of coding-based P2P streaming systems.

Key words: network coding, P2P streaming, dynamic segment granularity