The Research For The Key Technologies Of Multimedia Video Application In Wireless Sensor Network

There exists great promising and prosperous application prospect and potential for multimedia service applications in Wireless Sensor Network. In the thesis, we introduced an example for this kind of application, namely Mobile Augmented Visual Service(MAVS) with an purpose of transmitting real-time multimedia video traffic captured by video sensor nodes to mobile terminal at multi-hops mode so as to provide real-time play service,.The work covered in the thesis relates to three points, the first one is simulation research about congestion problem for QoS guarantee in MAVS, and the second one is simulation research about localization problem in MAVS, for the last one, it is design for MAVS in order for completing a test platform on the basis of research achievements of above two problems.Firstly in the thesis, as to problem of congestion mitigation for QoS guarantee, we analyzed a method of fuzzy logic based congestion estimation, and then tried to design and implement its simulation. In usage of a second-level cache, an emergency algorithm for congestion mitigation was presented during simulation. According to estimated network congestion, it is invoked to handle packets of different priority traffic after their being routed, make them participate in competence, so as to guarantee low packets dropping for high priority traffic, and in the condition of ensuring the lowest endurable limitation for QoS guarantee, then properly abandon some unnecessary packets for low priority traffic, and eventually achieve the goal of congestion mitigation as well as QoS guarantee. Simulation was conducted to verify the efficiency and feasibility of when fuzzy logic and emergency algorithm tried to mitigate congestion.Secondly, in the thesis, as to problem of localization, we analyzed a novel efficient and cost-effective area localization scheme. After analyzing the deficiency of two assumptions on the basis of which the localization scheme is deduced, we made extension for it. Based on the extension, we made simulation design for it, and presented boundary triggering implementation method during the process of design. As far as the implementation method is concerned, by utilizing a timer with triggering function, it is able to trigger and enable the function of broadcasting beacon on the boundary scope of sensors so as to achieve the objective of localization. Following the implementation method, we completed the simulation implementation for the localization scheme. And simulation results indicated that the implementation method gave the strong support for the localization scheme, and simultaneously verified the correctness of the localization and the feasibility of the implementation method as well.Lastly, based on the deeper research and results achievement of two above key technologies in MAVS, in a point view of software design, we made detail design for every module relevant to MAVS as well as their interface, and also established an initial demonstration platform at the environment of Linux, for testing multimedia video stream transmission in WSN.