5G Mobility Mechanism for EPC and 5GC Cell Reselection
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Solution Overview
Problem
Current technologies lack mechanisms for effective cell reselection between cells managed by eNB and ng-eNB in 5G systems, which are essential for enabling UE to camp on higher priority cells and leveraging new features supported by ng-eNB connected to 5GC.
Innovation Solution
The implementation of methods and apparatus that allow UE to receive system information including cell lists and priority details, applying an offset value for cell-level ranking criteria when calculating the priority of cells connected to 5GC, ensuring UE can camp on cells managed by ng-eNB with higher or equal priority, thereby enhancing mobility mechanisms in both EPC and 5GC scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cell reselection mechanisms are defined for eNB cells only, then legacy LTE systems can maintain backward compatibility, but 5G systems cannot leverage new features supported by ng-eNB connected to 5GC
Solution Approach 1:
The patent extends the existing cell reselection mechanism to handle both eNB and ng-eNB cells by introducing a unified cell list information element that can contain cell identifiers from both types of base stations. This allows the same reselection procedures to work across legacy LTE and 5G systems, enabling universal compatibility while supporting new 5G features through ng-eNB connectivity to 5GC
2Device complexity
If UE applies standard cell reselection procedures without ng-eNB specific handling, then implementation complexity is reduced, but UE cannot prioritize cells connected to 5GC over EPC
Solution Approach 1:
The patent introduces ng-eNB specific parameters (cellIdentity, frequency, priority, q-OffsetRange) within the cell list information element that allow differentiated handling of ng-eNB cells versus traditional eNB cells. These localized quality parameters enable UE to apply specific offset values and priority rules for 5GC-connected cells without redesigning the entire reselection mechanism, thus maintaining low complexity while improving mobility efficiency
3Ease of operation
If frequency priority for ng-eNB cells is set equal to or higher than eNB cells, then UE can be directed to 5GC-connected cells, but network control flexibility is reduced
Solution Approach 1:
The patent makes cell priority dynamic by introducing q-OffsetRange parameters that can be configured differently for intra-frequency and inter-frequency neighbor cells. The network can dynamically adjust these offset values to control UE reselection behavior, allowing flexible prioritization of 5GC-connected cells when needed while maintaining the ability to revert to standard eNB-only operation when 5G features are not required
Data Source
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AI summary
Methods and apparatus for a mobility mechanism in the scenario including both enhanced packet core ( "EPC" ) and 5GC are disclosed. One method of a UE comprising receiving system information including a cell list from an eNB/ng-eNB, wherein, the cell list includes an identifier of a cell connected to EPC or an identifier of a cell connected to 5GC. Further, the identifier is a Physical Cell Identifier ( "PCI" ) of the cell, and the cell indicated in the cell list includes a serving cell for the UE and/or one or more neighbour cells of the serving cell. Further, the eNB/ng-eNB from which the system information is received can be the eNB/mg-eNB managing the serving cell for the UE or the eNB/mg-eNB managing the neighbour ceils of the serving cell.