Research And Design Of SIP Protocol Based On Embedded Operation System

Session Initiation Protocol is a real time communication control signalingprotocol that drafted by the IETE based on IP network. SIP is an application-layersignaling control protocol for creating, modifying, and terminating sessions with oneor more participants. It is one of the core protocol of the next generation network.In the application systems that based on the SIP protocol, the function of SIPsession control occupies a very important position, the SIP server is mainly providessome functions (such registration, call setup, call release, call hold, call transfer andcheck the timer) for SIP terminals; SIP terminal mainly initiates a call request. Withthe development of embedded technology, the communication of embedded terminalis widely used and has good prospects for development. And simple and flexible SIP itis more suitable for embedded systems with limited processing power. Therefore, thispaper introduces the SIP protocol stack for embedded applications and designs an SIPterminal based on embedded.The research work of this paper is mainly around the following aspects:(1)This paper introduces in detail the research status and development trend ofSIP protocol at home and abroad and studies and analyzes the logic structureof the SIP protocol stack, call flow of SIP session, the mode of directconversation and the mode of proxy service in-depth;(2)This paper designs the overall framework of embedded SIP terminal andpresents the solutions of system development platform on hardware andsoftware;(3)This paper designs the hardware circuit (such as power interface, reset circuit,memory interface, network interface, audio and video interface, USBinterface, LCD interface with touch screen, JTAG debug interface, etc) ofembedded SIP terminal based on S3C2440processor;(4)This paper designs the software logic structure of embedded SIP terminal, cutsand transplants the operating system of Linux for the design of systemhardware, designs and implements functional modules(SIP protocol stacks,RTP and audio and video codecs) and software of interactive interface by C,C++and Qt program design language;(5)This paper tests the functionality and performance of the embedded SIP terminal in the SIP server Asterisk of PC and SIP server of embedded, tests theconnectivity of embedded SIP terminal with Sipdroid phones on the Androidsystem and eyeBeam phone on the PC at the same time and analyses the resultsof the test. Test and analysis of this paper show that the design of embeddedSIP terminal achieves the design targets and requirements.