Multimedia Applications Systems Based on OFDM in Coal Mine

Geology circumstance of closed environment is extremely complicated and there are many hidden trouble. In this paper, the signal sources of communication coal mine system are described in closed environment firstly, and then a kind of comprehensive information communication system based on the OFDM technology is presented. This system makes wire communication combined mutually with wireless communication by tandem adapter. Wireless communication system primarily include through-the-earth communication, inductive communication and microwaves communication system, etc Wireless communication is used in mining area or in the time of sudden accident, Power line or leaky cable is used in main lane. The technology of OFDM combines with multiple access technology and various modulations technology easily. This system makes use of the advantage of OFDM technology to provide many kinds of access service in mine. There are different grades and different rates for many consumers at the same time in these access services. The different modulation methods of sub-carries in this system increase flexibility and adaptability. The system not only fulfils the usual demand of produce communication monitoring, but also considers sudden accident, attains the state where the mining area arrives where the signal transports. System structure of the powered support´ communication system and hardware design, main motion flow of the monitoring equipment were pointed out in this paper based on fully mechanized mining face in thin coal seam for complete sets of electric control equipment. From the work condition, the system can meet the requirements of the measurement and control in accuracy, real-time capacity and has high reliability.