Research Of Video Multiple Description Coding And Multi-path Transmission Over Ad Hoc Networks

Wireless Ad Hoc Network is independence and its topology changes dynamically.So it is widely used in some inconvenience emergency communications where can not pre-installed network facilities.However,because of network topology change and nodes move,the paths often break.So the channel bit error rate and packet loss rate are very high.Combined with collisions,signal attenuation,noise and other interference because of compete shared wireless channel,Ad Hoc network is facing limited bandwidth,energy consumption,together with broken links,transmission delay,data loss and many other issues.Video information has features such as intuitive,content-rich and so on.So how to transmit high-quality video over Ad Hoc networks has become an important research topic, and faces many challenges.According to existing Ad Hoc video transmission strategies do not consider the characteristics of human visual system and the importance of image content and when transmit video do not consider load balancing and paths optimization and other issues,the paper does an in-depth research and a large number of experiments on robust video transmission over Ad Hoc networks based on multiple description coding and multi-path transmission technology,and obtained the following results:1.On the basis of the analysis of Ad Hoc networks,give an in-depth research of the possibility of robust video transmission over Ad Hoc networks,combining with multiple description coding and multi-path transmission technology to transmit videos over Ad Hoc networks,and achieved good results.2.Use H.264/AVC coding standard for video coding over Ad Hoc networks, according to its intra prediction algorithm's shortcomings such as complex and time-consuming,proposed a fast adaptive thresholds algorithm based on MAD,making encoding time average reduced by 61.3 percent,and improved the coding speed. 3.Combined with content-based coding and layered multiple description coding, proposed a novel content-based layered multiple description coding scheme C-LMDC for robust video transmission over ad hoc networks.The proposed sheme fully taking into account the characteristics of human visual system and importance of image content,both subjective and objective quality of the reconstruction video are improved..4.On the basis of research multi-path transmission technology over Ad Hoc Networks,combining clustering algorithm with multi-path transmission technology, proposed a multi-path video transmission method LCMPT over Ad Hoc networks based on layered clustering algorithm.The method analysis bandwidth,delay parameters of multi-path,and then use layered clustering algorithm optimize the path,improved multi-path's bandwidth utilization,the average end-to-end transmission delay are reduced too.5.Use NS2 network simulator as the simulation platform,we designed a simulation system combine with C-LMDC and LCMPT.The simulation results show that the algorithm proposed in this paper take full advantage of limited bandwidth of Ad Hoc networks,reduce the average end-to-end transmission delay,and the objective and subjective video quality of the received video have markedly improved.