Research And Implementation Of Adaptive Control Technology Based On QoE For The Wireless Video Transmission

With the high-speed development of wireless communication technology, wireless video streaming is more and more widely applied. Bandwidth resources in wireless network are limited, and the transmission of real-time video data usually has a high requirement for network bandwidth. It also requires strict end-to-end delay and delay jitter. However, due to limited communication ability and the different way of working, a single wireless access technology can not provide end users with seamless multimedia experience. What’s more, because of the fluctuation of the wireless network, adaptive control in the process of video transmission is needed, which can match video quality and the time-varying network bandwidth, and improve the user experience according to the network environment and requirements of end users. So it is a great challenge to provide users with a seamless multimedia experience, considering the user equipment heterogeneity and the time-varying network conditions.Based on the research of wireless video transmission technology and the quality of user experience, the following three aspects are mainly studied in this thesis:(1) Primarily, for the purpose of solving the problem of controlling video traffic concurrent transmission in heterogeneous wireless networks to improve quality of experience, Pareto distribution and P/P/1 queue theory are applied to video traffic which has self-similarity and long correlation. Then a video traffic concurrent transmission control model in heterogeneous wireless networks is built. Finally, an explicit adaptive traffic allocation scheme based on Pareto distribution is proposed. The simulation results show that compared with commonly used traffic allocation scheme for load balancing, the proposed scheme has certain advantages in the aspect of time delay and packet loss rate.(2) For the purpose of solving the problem of matching the video quality and the time-varying network bandwidth, the adaptive technology is adopted in concurrent transmission system. In this thesis, an adaptive video transmission algorithm in wireless network based on QoE is proposed. In which factors such as play buffer, network bandwidth and QoE are used to select the optimal video playback quality, in order to provide the user with smooth video quality, and improve the user experience. The simulation results show that the algorithm is effective to reduce playback interrupt and switching times, improving the user experience.(3) Firstly, the wireless video transmission system based on QoE is designed and completed, and then experiment platform is built to verify the feasibility of wireless video transmission system based on QoE. At last, the test results are analyzed. Finally, conclusions are given and the next step of our research is put forward.