LTE-Assisted Multi-Link MIMO Channel Characterization for High-Speed Train Communication Systems

The performance of wireless systems and transmission technologies is ultimately limited by radio channels. This paper characterizes multi-link multiple-input multiple-output (MIMO) channels for future high-speed train (HST) communication systems. The channel characterization is based on field measurements in a dedicated long-term evolution (LTE) network along a high-speed railway line of China. The raw channel data are collected by an LTE sounder with two antenna ports in the multi-link region between neighboring remote radio units of the network, which are further processed by a time-delay-window-based partitioning approach to acquire multi-link MIMO channel impulse responses. Before investigating the multi-link channel properties, MIMO channel characteristics for each single link in a plain viaduct scenario are analyzed and compared in terms of root mean square angular spread and spatial correlation. Then, the dual-link MIMO channel characteristics, such as correlation matrix collinearity and sum rate capacity, are newly presented and discussed. These results can provide the reference for realistic performance assessment of cooperative MIMO HST communication systems.