The rapid development of high-speed train and Metro communications has provided new challenges for the application of MIMO technologies. Therefore, we propose a three-dimensional (3D) multiple-input multiple-output (MIMO) channel model using leaky coaxial cable (LCX) in a rectangular tunnel. The channel model is based on geometry-based single-bounce (GBSB) channel model and the electric field distribution of LCX in the tunnel environment. The theoretical expressions of channel impulse response (CIR) and space-time correlation function (CF) are also derived and analyzed. The CFs for different model parameters (moving velocity and moving time) and different regions of the tunnel are simulated by Monte Carlo method to verify the theoretical derivation at 1.8 GHz. In the same parametric configuration of nonstationary tunnel scenarios, the time delay of the first minimum value of CFs for LCX-MIMO is 1/5 of the time delay of the minimum value of CFs for dipole antennas MIMO when the train moving velocity is 360 km/h. It is shown that, for MIMO system, the performance of using LCXs is better than using dipole antennas.

中文翻译：

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矩形隧道中使用泄漏同轴电缆的三维MIMO信道模型的时空相关

高速火车和地铁通信的迅速发展为MIMO技术的应用提出了新的挑战。因此，我们提出了在矩形隧道中使用泄漏同轴电缆（LCX）的三维（3D）多输入多输出（MIMO）信道模型。通道模型基于基于几何的单跳（GBSB）通道模型和隧道环境中LCX的电场分布。推导并分析了信道冲激响应（CIR）和时空相关函数（CF）的理论表达式。通过蒙特卡罗方法对不同模型参数（移动速度和移动时间）以及隧道不同区域的CFs进行了仿真，以验证1.8 GHz的理论推导。在非平稳隧道方案的相同参数配置中，当列车移动速度为360 km / h时，用于LCX-MIMO的CFs的第一最小值的时间延迟是用于偶极天线MIMO的CFs的最小值的时间延迟的1/5。结果表明，对于MIMO系统，使用LCX的性能要优于使用偶极子天线。