Positioning and Location-Aware Communications for Modern Railways with 5G New Radio

Providing high-capacity radio connectivity for high-speed trains (HSTs) is one of the most important use cases of emerging fifth generation (5G) New Radio (NR) networks. In this article, we show that 5G NR technology can also facilitate high-accuracy continuous localization and tracking of HSTs. Furthermore, we describe and demonstrate how the NR network can utilize the continuous location information for efficient beam management and beamforming, as well as for downlink Doppler precompensation in the single-frequency network context. Additionally, with particular focus on millimeter-wave networks, novel concepts for low-latency inter-carrier interference (ICI) estimation and compensation, due to residual Doppler and oscillator phase noise, are described and demonstrated. The provided numerical results at 30 GHz operating band show that sub-meter positioning and sub-degree beam direction accuracies can be obtained with very high probabilities on the order of 95-99 percent. The results also show that the described Doppler precompensation and ICI estimation and cancellation methods substantially improve the throughput of the single-frequency HST network.