Dynamic Scheduling Algorithms For Video Streaming Over Ad Hoc Networks

In recent years, the transmission of multimedia streaming overwireless networks has been a hot topic discussed by a lot of researches.With the rapid development of wireless communication and networkingtechnology such as3G, WLAN, LTE, etc, the demand for multimediaservice over wireless network has been soared over these years. Besides,the requirement for the quality of multimedia service is higher and higher.Wireless Ad hoc network is a kind of network constructed by a lot ofnodes which are combined freely. There is no center node and every nodecan work as a terminal as well as a router.Due to the flexible networkingmethod, the wireless ad hoc network has been widely used on applicatonssuch as emergency rescue, temporary meeting, wireless home network andso on.Unlike wired network, wireless network link is very unstable due tothe reasons such as limited wireless bandwidth, unstable channel, rapidchange of network topology and so on. On the other hand, the demand ofmultimedia service for bandwidth, delay, packet loss rate and network jitteris very rigid. Thus it is a very challenge job to enhance the quality ofmultimedia service over wireless network and which has been the focus ofa lot of studies in recent years.In wirless network, all the nearby nodes share the channel. Forwireless ad hoc network, due to the loss of scheduling of center node, themedia access (MAC) mechanism is rather important and become a keytechnology of ad hoc network. Media access not only effect the utilizationof network resource but also greatly effect the quality of service.Thus it isan important study point for the media access mechanism and the crosslayer optimization method has become an important point to improve theperformance of the protocols. The crosslayer method is a method which utilize the information of more than one layer to give combinedconsideration so that the over all performance can be optimized andimproved.In this paper, we start from the media access (MAC) mechanism anduse the cross layer design method with information from application layerand media access layer to optimize the schduling method for the videostreaming to improve the quality of multimedia service.We first discribe different kinds of media access protocols and themethod of service differentiation and analyze the the transmission of videostreaming over EDCA mechanism. Then a simulation platform is built andsimulation for the video streaming over EDCA is made to evaluate theperformance.After that, based on the linear adjustment and the method ofprobability scheduling, we propose a load adaptive dynamic mappingmechanism for video streaming transmission to improve the performance.And simulation in different situations is made to evaluate the performance.Then from the point of mathmatical analysis model of the mediaaccess mechanism and the video distortion model, combined with theinformation of network resources and loads, we propose a optimizeddynamic mapping method based on the minimum distortion. Andsimulations for the scheme are performed to evaluate the performance.At last, conclusion is made to conclude the paper.