Research And Implementation Of MCVideo Video Transmission Function In Broadband Trunking Switching System

MCVideo(Mission Critical Video)is a new generation broadband trunking communication technology standard proposed by 3GPP.MCVideo broadband trunking switching system is a video command and dispatch system based on MCVideo standard.MCVideo broadband trunking switching system has the functions of group affiliation,group management,group call,private call,video push,video pull,emergency call,transmission right control and ambient viewing call.At present,the MCVideo system is in its infancy,and there are few complete solutions for the MCVideo system at home and abroad.Therefore,the research and implementation the video function of MCVideo broadband trunking switching system is of great significance.Based on the review of the research status of broadband trunking switching system and its video transmission function at home and abroad,the video transmission function of MCVideo broadband trunking switching system is researched and implemented.The main contributions are listed as follows:1.Based on the composition of MCVideo system,the structure of MCVideo broadband trunking switching system is proposed,the video transmission function of the MCVideo broadband trunking switching system is described and the performance of MCVideo broadband trunking switching system is analyzed.2.A distributed highly concurrent media forwarding server architecture is proposed,which reduce the delay of media port's allocation by extending media forwarding server horizontally.The interface between participating MCVideo server and MCVideo terminal,participating MCVideo server and media forwarding server,participating MCVideo server and controlling MCVideo server are defined.Besides,the software architecture of participating MCVideo server and media forwarding server and the video transmission process of MCVideo broadband trunking switching system are designed.3.The adaptive control algorithm for video stream of MCVideo broadband trunking switching system is proposed.The algorithm uses an additive logarithmic growth factor to adaptively adjust the congestion window.In order to better adapt to the characteristics of the video group call of the MCVideo broadband trunking switching system,the user volume factor is introduced to adaptively adjust the congestion window.When the number of users increases rapidly,the video stream congestion window can be adjusted adaptively to prevent the network congestion of the MCVideo broadbandtrunking switching system caused by the rapid growth of the data stream.4.Based on the linux operating system,the participating MCVideo server and the media forwarding server's software is developed by using C and C++ programming languages.d The video transmission functions such as register,group affiliation,group call,private call,video push,video pull,ambient viewing call,priority call,alert and transmission control is are implemented.5.A test environment of MCVideo video transmission function in broadband trunking switching system is built to test the functions such as register,group affiliation,group call,private call,video push,video pull,ambient viewing call,alert,transmission control and the performances such as the delay of call's setup,the success rate of call's setup,the delay of media port's allocation and the loss rate of packets.The test results show that the developed MCVideo broadband trunking switching system video transmission function can meet the design requirements.