Research And Implementation Of Embedded Multifunctional SIP Terminal Based On PXA27x

With its simple and open design concept, mobility, scalability and good incomparable advantages, Session Initiation Protocol is gradually replacing H.323 as the core signaling protocol in the VoIP system. Due to its miniaturization, low cost, low power consumption, flexible-access and high integration, Embedded VoIP Terminal is one of the hottest realizations of IP phone. This thesis introduces the design and Implementation of a solution of embedded VoIP terminal based on the Windows CE 5.0 operating system. Using SIP signaling protocols, The VoIP terminal provides a variety of extended functions, such as speech coding and decoding, power management, video previewing and photographing, image map processing.This thesis mainly completes part of the hardware circuit expansion and VoIP software. The hardware of the Terminal consists of PXA27x processor, and other peripheral apparatuses such as audio, power management, camera, etc. Taking the open-source SIP and RTP stack as the platform, VoIP software codes and decodes speech data with G.729A algorithm. Through the optimization of G.729A algorithm, the coding efficiency improves by approximately 43%. The user agent can work in the network serverless mode and proxy mode, with the ability of registration, call and speech communication, and it can connect with the third-party SIP phone with good interoperability.Based on end-system hardware structure, the thesis elaborates the design and Implementation of application functions on Windows CE operating system. Using DMA interrupt transmission mode, the terminal is able to preview video and take pictures in the 15fps QVGA format through the quick-capture technology. Power management IC provides PXA27x processor with different power domains to achieve the switch among idle, sleep and wake-up modes, which helps to reduce the energy consumption. The embedded GIS platform eSuperMap provides SuperMap image tower technology, based on whom it is able to realize the fast browsing and editing of a GB-level image map, with "Hawkeye" feature.Through the testing and analysis on various functional modules in both functional and performance aspect, it is validated that the design of embedded multi-function SIP terminal is correct and practical.