UE Cell Selection Using CAG and Network Slice Associations
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Solution Overview
Problem
Current 5G systems lack clear mechanisms for User Equipment (UE) to consider network slice availability during cell selection and reselection, particularly in the context of Public Network Integrated Non-Public Networks (PNI-NPN), where restrictions on frequency bands, geographic areas, or applications are not effectively handled.
Innovation Solution
The implementation of control information exchange between the UE and the network, where the UE receives associations of Closed Access Group (CAG) IDs with network slice identifiers, allowing it to perform informed cell selection or reselection based on available network slices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE performs cell selection or reselection without considering network slice availability, then the cell selection process is simple and fast, but the UE cannot ensure proper access to authorized network slices in PNI-NPN scenarios
Solution Approach 1:
The network provides control information to the UE in advance, containing associations between CAG IDs and network slice identifiers. The UE stores this information before cell selection occurs, enabling it to make informed decisions during cell selection without adding complex real-time evaluation processes.
Solution Approach 2:
Control information acts as an intermediary between the network's network slice configuration and the UE's cell selection process. This intermediary data structure bridges the gap between network slice availability and cell selection criteria, allowing the UE to consider slice availability without directly querying the network during selection.
2Measurement precision
If the network provides detailed control information about CAG ID and network slice associations, then the UE can accurately consider network slice availability, but the signaling overhead and information management complexity increase
Solution Approach 1:
The control information is segmented into discrete associations between individual CAG IDs and network slice identifiers. Rather than transmitting a comprehensive network slice catalog, the network provides only the specific CAG ID-to-slice mappings that are relevant for cell selection, reducing overall signaling overhead.
Solution Approach 2:
The network provides partial information - specifically, only the CAG ID to network slice identifier associations that are necessary for cell selection decisions. This partial information approach avoids transmitting excessive data about all network slices while still enabling accurate slice availability determination for the purposes at hand.
3Adaptability or versatility
If the UE stores and processes associations between multiple CAG IDs and network slice identifiers, then the UE can make informed cell selection decisions, but the memory requirements and processing load increase
Solution Approach 1:
The UE stores control information locally in its memory, maintaining associations between CAG IDs and network slice identifiers specific to its operational context. This local storage approach allows the UE to have adaptability for cell selection while avoiding the need for centralized information management or continuous network communication.
Data Source
AI summary
A UE (1) receives, from a network (9, B), control information indicating an association of each of at least one Closed Access Group (CAG) ID with at least one network slice identifier. The UE (1) performs cell selection or cell reselection using the received control information. This allows the UE to take into account the availability of a network slice in cell selection and cell reselection in the case of a Public network integrated Non-Public Network (PNI-NPN), for example.