Design And Implementation Of Embedded VoIP Server

VoIP technology realizes real-time transmission of the voice signal through the IP data network. The appearance of VoIP technology greatly reduces the cost of the realization for voice communication, and with the spread network popularization as well as the great bandwidth increase, issues of voice quality of VoIP technology have greatly improved, which receives more and more attentions these days. At the same time, along with the rapid development of embedded technology, intelligent has penetrated into varieties of aspects in people's daily work and life. Therefore, studies that combine embedded technology and other technologies have become a hot topic today. Basing on the background above, a VoIP server system which is based on embedded system is designed in order to overcome the disadvantages such as huge volume, high cost and poor portability of system which is based on PC platform. The paper also provides the theoretical and technological supports for the development of small, quick, affordable and offline VoIP server system.Signaling protocol is the most important part of the VoIP system. Because of the great characteristics such as convenience, conciseness and good interoperability, the SIP signaling protocol has become the mainstream among other VoIP signaling protocols. In order to strengthen the future scalability for the design of embedded VoIP server and satisfy compatibility with other devices, SIP protocol is also chosen as the call control protocol this thesis. ARM microprocessor has advantages of high performance, low power consumption and low cost, which makes it become the preferred processor in industry control, mobile communications, consumer electronics and other embedded solutions. Thus, in this paper, the design of embedded system is also based on ARM microprocessors. Finally a Mini2440 S3C2440A processor from Samsung Company is chosen as the core development platform to support the SIP protocol and open-source SER server to implement the embedded system in this dissertation. Firstly the running environment is built on Mini2440 development platform for SER server, including the Boot Loader transplantation, transplantation of the embedded operating system kernel file and making the root file system. Then the cross-compilation SER server running on ARM platform is transplanted into the root file system. Finally we can achieve an embedded VoIP server which has function of call control and don't rely on PC platform.Tests of the performance in terms of function test, call established time test, speech quality evaluation and the hardware service condition test for this embedded system are conducted at last. The results to the whole analytic test of this system indicate that the embedded VoIP server designed in this project can achieve basic call control functions as well as possesses satisfactory stability and real-time processing, which also fulfill the requirements to this project. Meanwhile, the results illustrate that the VoIP server based on embedded system which is designed in this paper was completely feasible and the research purpose is satisfied in the project.