The Study And Implementation Of An Android Voip Voice Terminal Based On SIP

With the rapid development of network applications, VoIP technology has been widelyused. Recently， a text-based multimedia communications system standard calledSIP(Session Initiation Protocol) is in an increasingly use of video conferencing and VoIPapplications. When VoIP has just appeared, users usually enjoyed the convenience broughtby VoIP via a PC with limited user experience. With the popularity of smart mobile terminal,users can use mobile devices to make Internet phone calls through WIFI,3G network. Thereare four major operating systems for mobile terminals:Android、ios、symbian,、wp7, of whichAndroid enjoys the highest market share. Android is the name of a Linux-based open sourcemobile phone operating system, announced by Goole on November5,2007。 Since then, itattract a wide range of mobile device manufacturers’ favor because of its powerful functionsand its open features. In February2012, Android has occupied a52.5percent share of globalsmart phone operating system market and Chinese market share of68.4%, Android hasbecome a hot research field of intelligent terminal.This article first detailed several important protocols related to the VoIP applications,including SIP(Session Initiation Protocol)、 SDP (Session Description Protocol)、RTP(Real-time Transport Protocol)、RTCP (RTP Control Protocol), then expounds how theseprotocols synergies for the VoIP. After analysis of the prospects of Android and VoIPapplication, I use the open source SIPstack SIPDroid design a SIP-based embedded Androidvoice terminal. On this basis, I proposed and implemented an audio codec algorithm,optimized from Speex, and set up the test platform to make a function test.