Propagation graph theory based channel modeling method in non-line-of-sight type interval tunnel environment

Abstract

The invention provides a propagation graph theory based channel modeling method in a non-line-of-sight type interval tunnel environment. The method mainly comprises the steps of dividing a tunnel geometric model into multiple scattering point sets; arranging and combining the scattering point sets to obtain propagation paths; obtaining a transfer function of each propagation path according to cascading calculation of sub transfer functions between adjacent two scattering point sets on each propagation path in sequence, and adjusting the transfer function of each propagation path based on transfer probability; calculating the sum of the transfer functions of the adjusted propagation paths to obtain a transfer function of the non-line-of-sight type tunnel system; and performing inverse Fourier transform on the transfer function to obtain time domain channel impulse response of the non-line-of-sight type tunnel system. According to the propagation graph theory based channel modeling scheme for the non-line-of-sight type interval tunnel system provided by the embodiment of the invention, the propagation graph theory method is improved; the concepts of transfer probability and division planes are proposed; and therefore, the channel modeling method can be well suitable for channel modeling for interval tunnel systems with non-line-of-sight type rectangular tunnels, U-shaped tunnels and the like.

Description

technical field [0001] The invention relates to the technical field of tunnel channel models, in particular to a channel modeling method in a non-line-of-sight tunnel environment based on propagation graph theory. Background technique [0002] With the rapid development of underground rail transit, the demand for inter-train and passenger communication is becoming more and more urgent. It is particularly important to establish a complete underground rail communication system to provide a strong guarantee for the safe operation and control of trains, meet the diverse communication needs of passengers, and provide smooth, clear, low-bit-error images and user data. [0003] Nowadays, many researchers are applying the mature mobile communication system technology on the ground to the tunnel system. Common tunnel channel models include ray theory, modal theory, and empirical models. [0004] Ray tracing is an accurate method of searching ray trajectories, which can accurately p...

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Problems solved by technology

The transfer function between some invisible scatter points is also calculated accordingly. This scheme can only roughly describe the transfer function from scatter point to scatter point, and is not suitable for non-line-of-sight environments

On the other hand, for scatterers of different shapes, the statistical probabilities are different, and classical graph theory does not distinguish the transition probabilities between different scatterers

Therefore, classical graph theory cannot accurately describe the internal reflection of the set of scattered points

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