Cell Reselection in RRC_INACTIVE State Reducing Signaling Load
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Solution Overview
Problem
In 5G networks, user equipment (UE) in the RRC_INACTIVE state frequently initiates location updating processes due to frequent cell reselection based on frequency priority and cell measurement quality, leading to increased air interface signaling load.
Innovation Solution
The method involves determining the serving cell based on the configuration situation of the initial paging area, where the UE resides in the initial paging area to the greatest extent possible by redefining cell reselection criteria and priorities, reducing the need for location updates and signaling load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE in RRC_INACTIVE state uses the prior art cell selecting criterion (frequency priority and cell measurement quality), then the cell reselection can be performed according to optimal signal quality, but the UE frequently initiates location updating processes which increases the air interface signaling load
Solution Approach 1:
The patent applies local quality by differentiating cell reselection behavior based on location within the paging area. Cells within the initial paging area are given higher reselection priority than cells outside the paging area. This localized priority assignment reduces unnecessary location updates when moving within the paging area, thereby reducing signaling load while maintaining reliable connectivity.
Solution Approach 2:
The network side performs preliminary action by pre-configuring the initial paging area for the UE in RRC_INACTIVE state before the UE moves. This pre-configuration allows the UE to perform cell reselection within the paging area without triggering location updates, as the network already knows the acceptable service area. This preliminary setup prevents frequent signaling exchanges.
2Reliability
If the UE frequently performs cell reselection based on measurement quality, then the connection can be maintained with optimal signal, but the location updating process is frequently initiated increasing system complexity
Solution Approach 1:
The patent implements local quality by creating a differentiated reselection mechanism where cells inside the initial paging area have higher priority than cells outside. This local priority assignment allows the UE to maintain optimal connection quality within the paging area without triggering location updates, thereby reducing the frequency and complexity of location updating processes.
Solution Approach 2:
The patent applies segmentation by dividing the service area into two distinct zones: cells within the initial paging area and cells outside the paging area. This segmentation allows different reselection behaviors for different zones - free reselection within the paging area without location updates, and restricted reselection outside the paging area that triggers location updates only when necessary.
Data Source
AI summary
A method and a terminal device for cell reselection are provided. The method is applied to a terminal device. A connection between the terminal device and a network device is in a disconnected state, and the network device retains context information of the terminal device, the context information being used to establish a connection between the terminal device and the network device. The method comprises: when the terminal device triggers a cell reselection operation, determining a serving cell of the terminal device according to a configuration of an initial paging area of the terminal device.