Research And Design Of Digital Mobile Communication System In Coal Mine

Mine communication system is mainly used to resolve the problem of transmitting and acquiring staff's mobile information in mine, so that it can make every mobile personnel keep in touch with those communication target in any place and any time, As a most important part of techniques in the area of core district, it forms the coal mine specific communication system with coal private network and mining area ground communications network. Nowadays, there exists many defects ,such as low level technology, bad communication effect, low reliability ,isolated information and weak ability of preventing and resisting natural disasters in national mine communication system , and the technological level of communication lags behind the current requirements of coal mine safety in production. Thus, it is meaningful for designing and exploring a kind of entire mine mobile communication system to promote the construction of digital mine and satisfy the need of mine safety production.This dissertation mainly studied the digital mobile communication system of mine according to the characteristics of coal mine environment through analyzing present mobile communication systems in underground, such as leaky communication,earth communication and inductive communication etc. Firstly, it designed the systematic network topology. The system is a kind of wireless transmission structure based on wired network. The wireless transmission network is a belt network which sets three little cells as a cluster in every roadway and a base station in every cell. It regarded 900MHz electromagnetic wave channel as its private communication channel .The wired network combined the base stations through RS-485 bus in every roadway , made use of protocol gateway to connect with fibre ring network , and then it realized the rapid communication between underground and ground of mine. Secondly , this system chose MSP430F149 which came from TI company and owned the features of 16 bit and ultra-low power consumption to control the block send and receive message, TRF6900 to carry out radio frequency transceiver, CMX639 of MX.COM.INC to encode and decode audio signal. After designing the circuits of peripheral hardware of all chips, it constructed the hardware circuit of base station and mobile station. Thirdly, it designed the protocol of air interface based on TDMA and the protocol which referred to OSI/RM separated the signaling network of wireless interface into three layers , physical layer, data link layer and network layer .Finally, it designed the software of system and main subprogram and realized TDD data transmission of audio at thespeed of 8kbps.Research achievements of this dissertation is significant for constructing a high integrated and digitized mobile communication system in mine and improving the communication level of modern production in the area of coal industry , coal mine productivity and ability of preventing and resisting natural disasters.The successful application of the design scheme will produce huge social and economic benefits.