关键词: 基于通信的列车控制（CBTC）, 车-地通信, 无线信道, 路径损耗模型, 多径衰落模型

Abstract: Based on the tunnel geometry size, this paper calculates the cutoff frequency of the radio waves in the tunnel, then uses radio wave propagation path loss and multi-path fading modeling in subway tunnel, and makes a simulation of loss and fading channel for rectangular tunnel. In the end, it concludes that there is a direct path and there is not direct path for receiver signal level of the envelope. The simulation result shows that the received signal intensity is greater than －70 dBm when the AP distance is 400 meters. This conforms to the technical requirements.

Key words: Communication-Based Train Control（CBTC）, train-ground communication, wireless channel, path loss model, multi-path fading model