The present document is a technical report for Rel-17 NR support for high speed train scenario in FR2.
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: "Vocabulary for 3GPP Specifications".
C.A. Balanis: "Antenna theory: design and analysis ", Wiley, 2005.
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5G NR operating in millimeter wave bands (i.e., Frequency Range 2) is recognized as the technology capable of providing ultra-high data-rate transmission, thanks to the availability of enormous amount of bandwidth in FR2 and the advanced 5G NR design for FR2 beamforming-based operation. Inspired by the successful commercial FR2 deployment globally, more potential 5G NR deployment scenarios in FR2 draw attentions from the industry. Among those scenarios identified, high speed train (HST) scenario has the special importance, because of the fast expanding HST systems worldwide deployed and the great demands of high-speed connections from passengers and HST special services. This triggers the new and challenging demand for 5G NR FR2 HST scenario.
In existing study and work items led by 3GPP RAN4 (for either LTE or NR), high speed train scenarios under consideration has the operating bands up to 3.5GHz, however no existing works studied the more challenging millimeter wave frequency range 2, in which Doppler shift and Doppler spread will be further severe (e.g., for 240km/h with 28GHz, the Doppler shift is about 6.22kHz) and more challenging to radio resource management. Specifically, the existing FR2 RRM and demodulation requirements has not yet taken into account the impact of high speed in the above-mentioned scenario, where the channel model and mobility scenario need further study and the demodulation, measurement, mobility and beam management related requirements require to be further specified.
It should be noted that user equipment considered in 5G NR FR2 HST scenario is vehicle-roof mounted customer-premises equipment (CPE), which are expected to communicate with track-side deployed gNBs for the backhaul link and to further provide on-board broadband connections to user terminals and/or for other train-specific demands as access link.
This work will specify NR UE RF requirements, UE RRM requirements and BS/UE performance requirements for high speed train scenario with up to 350km/h in Rel-17.