The Design And Implementation Of Voice Communication Subsystem Of Mesh Emergency Network In Mines

ABSTRACT:At present, there is still no technical system of underground emergency communication in our country. To satisfy the significant demand for underground emergency communication, we design the communication system of Mesh emergency network in mines. This system uses wireless Mesh network technology; it can be quickly and flexibly deployed when the mine accident happens, and it has voice communications, video surveillance and environmental monitoring and other functions. This paper designs and implements the voice communication subsystem which is an important part of the communication system of Mesh emergency network in mines.In this paper, the author combines wireless Mesh network technology with VoIP technology to design the voice communication subsystem of Mesh emergency network in mines. This system is mainly based on the SIP protocol. Meanwhile the author successfully constructes the system’s voice server IPPBX, and designs the embedded wireless SIP voice terminal and main-control voice terminal.First, the author describes the wireless Mesh network structure, characteristics and comparison with other wireless network, then describes and compares two types of VoIP protocols H.323and SIP, which lays the foundation for the subsequent design and development. Then according to the underground tunnel structure and underground emergency rescue needs, the author designs the structure and functions of the voice communication subsystem of Mesh emergency network in mines, and uses Asterisk PBX IP02to build the system’s IPPBX. With the IPPBX, the author successfully designs and implements several voice communication functions of the subsystem like terminals management, group calls, conference, voice menus, voice mail, connect to PSTN and so on.Second, the author uses the popular Linux operating platform for embedded software development to design and implement the embedded wireless SIP voice terminal of the subsystem. The terminal is divided into four functional modules:SIP transaction processing, user applications, real-time transmission and network connectivity, which are interdependent and interrelated with each other. The author especially designs SIP transaction processing module and user applications module. Meanwhile based on the Windows PC platform, the author successfully uses C#language to implement the main-control voice terminal. Finally, the author sets up a test Mesh network and test Mesh-based voice communication subsystem. With the test Mesh network, the author uses the embedded wireless SIP voice terminal and the main-control voice terminal for SIP session tests, including SIP registration and SIP call. In addition, user information management function of the main-control voice terminal is tested. The results prove both terminals can be successfully connected to Mesh network and achieve expected functions.Then the author uses ClearSight Analyzer software to analysis the quality of service of the test Mesh-based voice communication subsystem, while tests the voice communication capabilities of the subsystem with CDR of the subsystem IPPBX. The test results prove that the subsystem has high network reliability and good quality of voice transmission, and it successfully achieves predesigned communication functions...