Based On The The Vxworks Voice Communication System Design And Realization

With the increasing development of embedded computing and control technology in recent years, the application of embedded system is becoming more and more popular and covering from daily life to industral areas. VxWorks is an embedded real-time oprating system that can be cut and run on target machine with high performance, therefore, it has been widely used in the fields which demand high real-time performance such as communications, military, aviation, spaceflight. On the other hand, with the continuous development and extensive application of network technology, network communication will become more and more important in embedded system. However, the traditional network was originally designed for transporting data reliably by peer-peer protocol, the characteristic of the traditional network increases network transporting load and leads to network delay. Therefore, it is not suitable to be used for transporting audio and video data which have large capacity and need high real-time performance.It can solve the problem well to use IP multicast technology and rea-time transport protocol. Multicast is one kind of IP technologies that can transport data stream from one point to multiple points effectively, and it can reduce the network traffic, improve efficiency of network communication and abate the load of the Internet servers. RTP/RTCP protocol is a real-time stream transport standard put forward by IETF. It introduces timestamp and increasing sequence number for real-time data stream transport, and uses RTCP to monitor QoS information, so it is able to be used for transporting real-time data efficiently, such as audio data, video data and fax data.This thesis dissertated a voice communication system which was designed for satisfying actual demand of a military aircraft, and it's able to achieve voice communication and related control during all the crew members and control center. By using IP multicast technology and real-time transport protocol, this system can transport real-time voice data reliably. Comparing with the existing voice communication systems, this system has higher reliability, higher real-time performance and less transporting data. In addition, it also can mix multi-channel voice data. In conclusion, the main contents of this thesis are as follows:1. Introduced the relevant theory about IP multicasting, the key points are its addressing and routing mechanism2. Researched on real-time transport protocol, detailed describe the header format of RTP and RTCP3. Explained the main function about the voice communication system based on VxWorks, introduced the hardware platform, software system development platform and development tool, refered to an open source RTP library JRTPLIB as well4. Finally, detailed described how to use the library JRTPLIB to implement the embedded voice communication system on VxWorks platform...