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Research On The Key Technology Of Real-Time Video Application In IP Network

Posted on:2007-07-03Degree:DoctorType:Dissertation
Country:ChinaCandidate:X Q GuoFull Text:PDF
GTID:1118360212965516Subject:Control theory and control engineering
Abstract/Summary:PDF Full Text Request
With the rapid growth of multimedia content in today's network links, research on the efficient transmission of real-time video application that has strict Quality of Service (QoS) request than traditional data application in IP networks is necessary and practical. In order to improve video flows transmission quality over IP network and achieve higher level of utilization, video compression encoding is used that leads to the errors nature of channels and the error propagation property. To adapt to the changes in network conditions, both application layer techniques and network techniques are proposed. In this paper, we focus on the issues of transmission over unconnected IP channels.The main work includes:(1) In order to improve MPEG-4 video decode quality, based on the MPEG-4 standard RVLC (Reverse Variable Length Coding) recovery method, a new error localization recovery scheme called IRVLC (Improved RVLC) is proposed. The IRVLC scheme fully uses the local-information of frames and adopts different strategy for I frame and P frame, then overcomes the flaw of conservative discarding existed in standard RVLC recovery method, and it is fully compatible with the MPEG-4 standard.(2) QoS supports of multi-class data service in IP network generally includes packet delay, throughput and loss rate, while the majority past research focus on either minimizing packet delay and loss or maximizing user throughput. An algorithm DPAA (Dynamic Proportional Adaptive Algorithm) for assuring the difference service under heavy traffic load based on proportional differentiated services (PDS) model is proposed. The scheme takes into account the throughput, delay and loss rate of packets between classes simultaneously. Simulation indicates that the DPAA has a better performance compared to the previous work and is suited to video application transmission with burst property.(3) We analyze the property of video traffic through trace, and then compare the queue performance of video traffic model under a unified network simulation environment, especially the models which support the multi-layer encoding. The result is that the model is more complex and then it can capture the property more exactly, and this is useful for traffic multiplexer.(4) We analyze the performance of admission control which admission judge is based on effective bandwidth through simulation, the result is that the lognormal marginal distribution assumption of video traffic is more exactly than Gaussian marginal distribution assumption, and the complex traffic model only improves the system performance such as packet loss rate but not the multiplexer performance, and that is useful for bandwidth assign in DiffServ network.(5) We summarize the solutions of representative applications of video service based IP, and research on their performance and key technology. A framework based on full IP network is proposed, and then some implement advice according to our forenamed result is put forward. In the end, a design case is implemented based on the framework.
Keywords/Search Tags:video service, video transmission, error location and recovery, packet schedule, traffic model, admission control
PDF Full Text Request
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