NTN Cell Reselection Using Service Time and Ephemeris Data
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Solution Overview
Problem
In 5G NR terrestrial networks, cell reselection based on RSRP and RSRQ measurements in non-terrestrial networks (NTN) leads to unreliable 'ping-pong' effects due to the large cell radius and lack of obvious near-far effect, causing untimely and inefficient cell reselection.
Innovation Solution
A cell reselection method that utilizes auxiliary information such as coverage and ephemeris data to determine service time, allowing terminals to perform cell reselection based on the time the NTN service cell can provide service, reducing the influence of signal quality fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cell reselection is performed based on RSRP and RSRQ measurements in NTN, then the terminal can perform cell reselection using conventional terrestrial network methods, but the large cell radius and lack of obvious near-far effect cause unreliable ping-pong effects and untimely cell reselection
Solution Approach 1:
The patent changes the basis for cell reselection from signal quality parameters (RSRP, RSRQ) to time-based parameters (service time, coverage duration). The terminal determines cell reselection timing based on when the NTN service cell can provide service, which is derived from coverage information and ephemeris data, rather than continuously measuring signal strength. This parameter transformation resolves the contradiction by making cell reselection reliable in NTN conditions where signal measurements are ineffective.
2Measurement precision
If the terminal continuously measures RSRP to determine cell reselection timing, then the terminal can maintain connection quality, but the measurement becomes unreliable due to the large cell radius and moving NTN base station causing insignificant near-far effect
Solution Approach 1:
The patent replaces the mechanical measurement system (RSRP/RSRQ signal strength measurement) with an information-based system using auxiliary information. Instead of measuring physical signal parameters, the terminal uses coverage information and ephemeris data to calculate service time and determine cell reselection timing. This substitution resolves the measurement reliability issue by eliminating dependence on signal measurements that are inherently unreliable in NTN environments.
3Productivity
If the terminal performs cell reselection based on signal quality in NTN, then the terminal can follow conventional cell reselection procedures, but the large cell radius causes untimely and inefficient cell reselection
Solution Approach 1:
The patent applies preliminary action by having the terminal obtain auxiliary information (coverage information, ephemeris data) in advance and calculate service time before cell reselection is needed. The terminal determines the time period when the NTN service cell will provide service and performs cell reselection based on this pre-calculated timing rather than reacting to signal quality changes. This advance preparation resolves the timing issue by enabling timely and efficient cell reselection adapted to NTN characteristics.
Data Source
AI summary
A cell reselection method includes: determining, according to service time determined based on auxiliary information, an operation of performing cell reselection, wherein the service time is time in which a non-terrestrial network (NTN) service cell can provide service to a terminal, and the auxiliary information includes at least one of coverage information of the NTN service cell, ephemeris information of the NTN service cell, or information of reference service time in which the NTN service cell can provide service.