The Research And Optimization Of Digital Mobile Video Transmission Scheme Based On Channel Characteristics

Due to the high bit error rate(BER)of the wireless channel,the quality of the decoded video will be heavily damaged in wireless video transmission.What's more,the channel bandwidth of wireless network is very limited,while the data amount of video is huge.So this paper is focused on the optimization of mobile video transmission.The optimization direction is improving the robustness of the wireless video transmission system,and implementing the adaptive transmission of mobile video across the fast changing channel,so as to guarantee the maximum throughput of the wireless network.We first studied the error control techniques in wireless video transmission,our concentration is the error resilience technologies of H.264/AVC encoding.On this basis,we analyze the existing schemes on optimizing the transmission of mobile video with the use of channel encoding,constellation modulation,and the Joint Source Channel Coding,among which SoftCast is an analog video transmission scheme,and FlexCast is a digital scheme.Since the limitations of existing schemes are analyzed,an unequal error protection(UEP)scheme is implemented and verified in this paper.To achieve UEP,the H.264 bit stream is divided into different segments according to different importances,and the differential protection mechanisms in gray constellation mapping is utilized.The experimental results show that the PSNR of the UEP scheme can be improved by 5dB averagely.Additinally,when the wireless video transmission is faced with poor channel condition and high requirements for real-time transmission,we propose the unequal packet loss protection(ULP)scheme,which can save nearly 20%of the channel bandwidth.