| With the continuous development of coal mine production management and IT, the demand of Mine wireless communication systems has become more and more high; However, the mine tunnel is a very complex environment, Serious multi-path phenomenon will happen when signal transmitting within the mine tunnel, it can cause the signal attenuation and bring about multi-path fading. Multi-path fading is the main problem faced by mine communication system; it seriously affects the development of the mine wireless communication technology. This paper aims to research the anti-multi-path fading problem of coal mine communication system.The paper first conducts a depth analysis of complex communications environment of the coal mine, and the signal propagation characteristics of mine tunnel and factors that influencing signal propagation, obtaining multi-path fading problem is the main problem of mine wireless communication system. To solve this problem, first proposing the application of spread spectrum communication system based on the Rake receiver in the wireless communication of mine. Through to the system's anti-multi-path performance theory analysis and simulation, obtaining the Rake receiver technology can take advantage of the multi-path signal components, and good resistance to the channel multi-path fading; However, the mine tunnel environment is more complex, and more multi-path components, When the multi-path routing over a certain number, the system's performance will drop, and the high complexity of the receiver to implement difficult.Then the paper proposes the MIMO-OFDM-based communication system in the mine wireless communication, and conducting depth analysis and Matlab simulation with the system's anti-multi-path performance. Because MIMO-OFDM system combines the characteristics of MIMO and OFDM, it not only Can improve the spectral efficiency of the system, increase the channel capacity, but also can resist the frequency selective fading and multi-path fading, consequently reduced the error rate of the system, improved the performance of wireless communication systems in multi-path transmission environments, enhanced the reliability and accuracy of the transmission, it has broad application prospects. |
