Design And Implementation Of Voice Dispatching Communication System For Mine Rescue Based On Mesh Network

Coal is our precious natural resources, while promoting economic development rapidly, but also bringing frequent mine accidents. However, disaster rescue communication technology is weak in our country now, it is necessary to develop a complete set of mine emergency disaster rescue communication system.This thesis combines wireless Mesh network technology and VoIP technology to implement voice dispatching subsystem, solving traditional underground cable communication many disadvantages, such as the cost is lower, network can be deployed faster after the cave-in,and improving the efficiency of rescue.According to the function needs of voice dispatching subsystem, This paper use Mesh as backbone network and achieve secondary development for Asterisk voice dispatching server based on SIP protocol, implementing forced demolition, forced insertion, meeting and other special call function. Then the paper use C++language to develop the voice dispatching station software on visual studio2008, and control the downhole IP phone through sending operating command to voice dispatching server.First, this article introduce the structure of Mesh network and elaborates the differences and advantages with other network and state the entities, message command and call process of SIP protocol, which lay the foundation for next development.Then the paper describes the voice dispatching system overall design framework and Asterisk voice dispatching server design on IP02and analyze the development process of the voice server, including the installation and configuration of Asterisk, call process, AMI module, audio processing module, the SIP message processing module, the Web management module. It has realized the basic call and special call function.Then the author illustrate each function module of voice dispatching station and use dynamic library of the ppsip and sound card driver to develop voice dispatching station, including the realization of the login module and main interface module.This paper expounds the development process of voice dispatching station and key technologies such as the priority scheduling strategy, extension status display, speech process etc.Finally, the author has built wireless Mesh network which has24jumps and the distance is up to15km in the grand canal, and test bandwidth, delay, signal strength, the test data results show that the Mesh backbone network completely satisfied the data transmission request of voice, video, environmental parameters etc. The author also built Mesh network to test voice dispatching system in campus, using ClearSight Analyzer software to caught data packet for validating forced demolition, forced insertion, meeting. The voice QoS report display packet loss, delay jitter and delay results, and the data show that all reach the requirements of voice communication and the whole performance of voice dispatching system is good.