Angular Power Distribution of Wireless Channel in Mine Tunnels

The statistical characteristics of the angular power distribution of the wireless channel in mine tunnels are the concern of this paper. Firstly, we develop a ray-based channel model which provides the angular power spectrum (APS) in tunnels. We discuss the allowed rays existing in a tunnel based on the modal theory. The number of the allowed rays is limited. The directions of the rays are discrete. They are influenced by the excitation conditions. And then we deduce the propagation parameters as the functions of the direction of arrival (DOA) for each ray to reduce the computational burden. The model is validated by experimental measurements. Then theoretical results deduced from our model show that APS in the tunnel follows Gaussian distribution. For vertical polarization, the spread of the azimuth angle is more sensitive to the excitation conditions. While for horizontal polarization, the spread of the elevation angle is more sensitive.