White-List Cell Reselection for Unlicensed NPN Spectrum
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In next-generation wireless communication systems like 5G NR, the need arises for improved cell selection and reselection mechanisms, particularly in unlicensed spectrum scenarios where multiple PLMNs and NPNs operate without coordination, leading to inefficient UE camping on non-best cells that do not belong to the registered PLMN, resulting in wasted time and power consumption.
Innovation Solution
Implementing a White List-based cell (re)selection procedure for RRC_IDLE or RRC_INACTIVE UEs, where system information or dedicated signaling provides UE with a list of allowed PLMNs and associated area information, such as PCI, Cell ID, RANAC, RAN Area ID, and TAC, to restrict evaluations to candidate cells belonging to the allowed PLMNs, thereby optimizing cell reselection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UE performs cell selection/reselection without White List restriction in unlicensed spectrum, then UE can detect more cells including non-PLMN cells, but UE camps on non-best cells that do not belong to registered PLMN resulting in wasted time and power consumption
Solution Approach 1:
The system provides UE with a White List containing area information (PCI, Cell ID, RANAC, RAN Area ID, TAC) associated with allowed PLMNs before cell selection/reselection. UE uses this pre-provided information to restrict its cell evaluations only to candidate cells that belong to allowed PLMNs, avoiding unnecessary measurements on non-PLMN cells and reducing power consumption while maintaining adaptability to detect relevant cells
2Reliability
If UE evaluates all detected cells during cell reselection, then UE can find the best cell, but UE wastes time evaluating cells that do not belong to registered PLMN
Solution Approach 1:
The system extracts and provides to UE the specific area information (PCI, Cell ID, RANAC, RAN Area ID, TAC) of cells belonging to allowed PLMNs through White List. UE uses this extracted information to filter and restrict its cell evaluations only to relevant candidate cells, eliminating time-wasting evaluations on non-PLMN cells while maintaining reliable cell selection accuracy for allowed PLMNs
3Loss of information
If UE performs measurements on all cells in unlicensed spectrum, then UE has complete information for cell selection, but UE consumes excessive power for unnecessary measurements
Solution Approach 1:
The system provides UE with a pre-configured White List containing area information of allowed PLMN cells before UE performs measurements. UE uses this preliminary information to restrict measurements only to candidate cells that match the White List criteria, avoiding excessive power consumption from measuring all cells in unlicensed spectrum while maintaining sufficient cell information completeness for allowed PLMNs
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method performed by a User Equipment (UE) for cell (re) selection includes the UE storing allowed Non-Public Network (NPN) information that is in a form of a Cell Access Group (CAG) Identity (ID) list or in a form of a Stand-alone Non-Public Network (SNPN) ID list, receiving NPN information and area information associated with the NPN information via a System Information Block (SIB) Type 1 (SIB1) broadcast by a cell, the NPN information including an NPN ID list, performing a first procedure according to the allowed NPN information when the allowed NPN information is in the form of the CAG ID list, and performing a second procedure according to the allowed NPN information when the allowed NPN information is in the form of the SNPN ID list.