移动网络视频传输速率自适应控制技术的研究

Research on Self-adaptive Control Technology of Video Transmission Speed in Mobile Networks

目前移动终端上的视频传输与交互技术得到了广泛应用,但由于移动网络带宽波动等原因,网络中的可用带宽往往会小于视频的传输速率,造成视频在传输时出现丢包的情况,对视频传输与交互的质量产生了较大影响。因而如何根据网络状态的变化实时地调整视频的传输速率,从而降低传输过程中的丢包率,保证视频传输与交互的质量,具有至关重要的意义。针对视频传输对于移动网络环境的特殊要求,设计了一种适用于移动网络视频传输的自适应速率控制方法。该方法将TCP协议拥塞控制方法进行了改进,在视频传输的过程中依据网络状态的变化情况动态地调整视频的传输速率。仿真实验结果表明,该方法能够保证传输速率在一定范围内平稳变化,提高了网络可用带宽的利用率,降低了传输过程中的丢包率,基本能够满足移动网络环境下对于视频传输与交互质量的要求。

Nowadays video transmission and interaction on mobile terminals is widely used. However, because the bandwidth of mobile network often fluctuates,it may lead the available bandwidth lower than the transmission speed and packets loss transmitted in network, which in turn affects the quality of video transmission and interaction. Thus how to change the transmission speed timely according to the change of network status, decreasing packet loss ratio in transmission, guaranteeing the quality of transmission and interaction, is very cru- cial. Aiming at the specific request of video transmission in mobile network environment, a self-adaptive speed control method applicable for mobile network video transmission is put forward. It improves the congestion control method used for TCP, and adjusts transmission speed dynamically according to the variation of network situation during the process of video transmission. The result of simulation shows that this method can guarantee the transmission speed change placidly within limits, which improves utilization ratio of network available bandwidth, and reduces packet loss ratio during transmission. Thus it can basically meet the requirement of video transmission and interaction quality in mobile networks.