Design And Implementation Of Underground Wireless Communication System

With the rapid development of wireless communication, the lack of reliable and efficient wireless communication technology in coal mine and the other buildings underground is still restricted the safety and efficiency. The coal mine wireless communication channel is clay, rock and some other high conductivity medium, so it is difficult for wireless communication. But wireless communication is very significant to the rescue of life and property when incident happens. The research of wireless communication to penetrate the rock is particularly important. In view of the problems above, this paper designs a wireless communication system, which can be used in underground and mine communication.This paper introduces the difficulties of underground wireless communication, the organization principle, key technology of underground wireless communication system and the design of the key modules. First, this paper describes the current research at home and abroad on communication technology of coal mine underground, discusses the existing way of wireless communication in mine and the trend of mine communication. This paper analyses the features of underground channel media, discusses the influence of electromagnetic parameters and frequency to the electromagnetic waves travel, calculates the correlation of the coefficient of relations that can be used for underground communication, discusses the communication way and calculates the antenna parameters. Second, according to the requirements, the circuit schematics of ground radio and PCB of each module are designed and the welding debugging and experimental testing is finished and proved to be achieved the requirements. Finally, according to the features of the rock communication, we choose the POCSAG coding format, designing the software of following parts: encoding and decoding, error correction algorithms and transmitting and receiving. A simulation is made and the results meet the requirements perfectly.Theory, the work and conclusions in this paper provide theoretical support to realize the ground and underground flexible and reliable communication and have some practical significance.