支持区分服务的自适应链路层HARQ控制策略

Adaptive Link-Level Hybrid ARQ Mechanism Based on Differentiated Service for Wireless Media Streaming

提出了一种用于无线实时流媒体传输的自适应链路层HARQ控制策略,针对不同的信道状况或业务服务质量的要求动态选择混合AQR方案.该策略采用跨层设计的方法,基于增强型GM(1,1)预测当前的网络状态,自适应地调整ARQ参数Nmax;另一方面,在应用层采用自适应FEC策略,在视频源数据和冗余数据之间动态分配网络带宽.理论分析和仿真验证表明,该策略能使接收方获得最大的可播放帧率,有效地提高流媒体传输的可靠性和实时性.

In this paper,an adaptive link-level Hybrid automatic repeat request （ARQ） mechanism was proposed for wireless media streaming,in the hope that the media could be played on receivers with high quality. It allocate the optimal HARQ schemes for different traffic streaming,according to channel condition or differentiated QoS requirements dynamically. The mechanism,based on cross-layer optimization design,predicts the packet loss rate using the enhanced GM （1,1） model,and adjusts the ARQ parameter Nmax. Besides,an adaptive FEC at the application layer was used to adjust the sending rate of MPEG video frame adaptively and to allocate the network bandwidth resource between the MPEG video source data and the redundant data dynamically. Both the analysis and simulation results demonstrate that the proposed mechanism can significantly improve quality of media streaming,in terms of playable frame rate,reliability and real-time performance on the receiving side.