A LTE-based channel measurement method for high-speed railway communications.

Channel measurements are the prerequisite condition for the design of the next-generation high-speed railway (HSR) communication system. Because of the measurement restriction and measurement efficiency issues of applying conventional channel sounders in HSR scenarios, railway-network-based channel measurements are becoming quite attractive. In this paper, a method that employs the cell-specific reference signal in long-term-evolution (LTE) railway networks as the excitation signal to perform HSR channel measurements is presented. This method is implemented by a novel channel measurement system composed of existing LTE railway networks and a dedicated LTE receiver, which can efficiently collect the time-frequency-space channel data and is able to measure different communication links simultaneously. Based on this system, field measurements that consider both direct coverage and relay coverage schemes are conducted on the Beijing-to-Tianjin HSR in China. Statistical results, involving path loss, Ricean K-factor, root-mean-square delay spread, single-link spatial correlation (SC), and multilink SC, are derived, which not only confirm the viability of the proposed method but also provide realistic HSR channel characteristics for the research on future HSR communications