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

Coal resources occupy a pivotal position in China’s economic and social development, and its industry is one of the basic industries of china. However, the coal mine safety situation seriously restricts the development of the coal industry. As the premise to carry out scientific decision-making, how to make the communication between the underground rescue base and the ground dispatching command centerthe timely and reliably is one key factor to reduce the number of casualties and economic losses.At present, most emergency communication systems can not be used in the underground. And the underground communication technology, network and facilities often lose utility in the mine safety accident. The above situation puts forward urgent requirements for the establishment of a set of voice dispatching, roadway personnel positioning, wireless video monitoring and environmental parameters monitoring as one of the underground disaster relief visualization wireless communication system.This paper mainly studies the design and implementation of voice scheduling subsystem based on Mesh network. Comprised of voice calls, group calls, telephone conference and other functions, the voice dispatching subsystem can be used to control voice traffic and schedule of disaster relief voice communications based on the actual situation of the rescue scene, which has very important practical significance for the scientific implementation of the rescue plan.In this paper, we first study the wireless Mesh network, drawing the conclusion that it has many advantages such as flexible structure and strong scalability. After that, we analyzes the business requirement, the system logic and the topology structure of the Mine Rescue Communication System, building a hybrid wireless Mesh backbone network.VoIP technology is an important basic technology of voice scheduling subsystem. Therefore, its basic principle, the encoding and decoding technology and the signaling and transmission protocol are analyzed in detail, the same time we focuses on the component, message form and call flow of Session Initiation Protocol (SIP).The voice dispatching system is composed of IPPBX, communication terminal and dispatching platform. Taking IP02 as the hardware platform, this paper programmed Asterisk deeply to build a SIP IPPBX, including user management, group call, telephone conference, etc.. Secondly, the voice scheduling platform is developed, which enables the administrator to complete the voice scheduling function on the visual interface. In addition, we developmented the communication terminal software in the ToughEX(?)hone-431-MAXI Explosion-proof hand-held machine based on Android system.In order to verify the actual performance of the system, this paper tests the performance of the wireless Mesh backbone network and the QoS of voice dispatching subsystem, respectively. The test results show that the network throughput, delay,jitter and node field strength of the wireless Mesh backbone network, the QoS index of the subsystem, such as packet loss rate, delay, jitter and packet loss sequence, are fully meet the requirements of the system.