Research On Performance And Capacity Of MIMO System In Mine

With the development of mobile communication and wireless technology, the need in the coal mine is particularly urgent as more and more wireless communications are applied in different industries. Coal mine environment is full of complexity, Roadway is changing not only because mine is developing all the time, but also the tunnel wall materials, shapes and structures differ from each other. So the underground tunnel is a heterogeneous, variable, complex confined space, which surrounding dust and other special gas. The electromagnetic wave transmission is influence by refraction, and scattering, adsorption and electromagnetic interference of high power equipment from tunnel structure, rock, locomotive equipment, dust, special gases. MIMO technology has the advantages of resisting to multipath fading and improving the channel capacity, so in this article MIMO technology is applied to combat severe multipath fading.At first, the advantages and disadvantages of the existing mine wireless communication technology and the characteristics of the underground environment is discussed, three-dimensional GBDB model of MIMO channel and the space-time correlation function of the model in the mine roadway environment are established and deduced, the simulations show that the channel capacity is affected by correlation seriously. antenna selection techniques can reduce the correlation among the antenna units in order to increase the channel capacity. In this section the core idea and its characteristic of the optimal selection algorithm, incremental and decreasing algorithms for antenna selection is proposed. On this basis, a new algorithm applying the former researchers' advantage of "a selected two antennas” is proposed, which avoids the matrix inversion complexly calculations in the process of computational capacity, computer simulation shows that the amount of calculation are reduced greatly while the performance of it changed little.Finally, to adapt the special environment of the mine roadway and solve wireless communication problem, when the distributed MIMO antenna system is used, under the condition of the unknown channel state, a new power allocation scheme based on multiple mode model is proposed in this paper, the simulation results show that this scheme can significantly improve downlink capacity in a underground environment.