Research Of The Key Technologies In Mine MIMO Communication System

Mine laneway is limited non-free space, and signal in the limited space transmission will lead to reflection, scattering phenomenon, and form the multi-path fading influence. In this dissertation, the complex wireless communication environment is analyzed in coal mine underground, and signal in the mine laneway propagation and influencing factors are studied. At present, the main problem of mine wireless communication is multi-path fading influence, and the existing underground wireless communication systems could not be a solution for the problem. To solve the problem, the multiple-input multiple-output (MIMO) technology is proposed in the dissertation.MIMO technology is multi-antenna unit at the sender end and the receiver, using a radio channel the multi-path propagation, which improve the system available freedom, construct more parallel channel in the space, and improve the data transfer rate and signal quality without increasing the bandwidth. At the same time, the space-time codes technology of the MIMO system combine channel coding technology and array processing technologies, which introduces the time and space correlation of the sending signal in different antenna. The communication system can also get the sub-set gain and coding gain through space-time signal processing in the receiver.In this dissertation, the environment of the mine wireless communication transmission is analyzed firstly, the propagation characteristics and capacity of the MIMO channel are discussed, the channel models of MIMO system is set up, and spatial correlation is analyzed. Then several space-time coding techniques of MIMO communication system are analyzed, and channel estimation of MIMO system is discussed. At last, mine MIMO band communication system is designed, and the performance of the system is studied. According to analysis and research of the communication system, MIMO system makes full use of the multi-path propagation, besides, the system can also get diversity gain and encoding gain, so MIMO technology can be effective against the mine roadway multi-path fading and improve the reliability of the communication system.