Cell Selection via Target Frequency Bands and TAI for Slice Access
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Solution Overview
Problem
Existing communication systems require UE to configure frequency band information corresponding to slices, leading to inconsistencies with network support, resulting in potential selection of unsuitable cells for slice access.
Innovation Solution
A method that allows the UE to select cells without configuring frequency band information, using target operating frequency bands and/or TAI provided by the AMF to ensure compatibility with desired network slices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the UE configures frequency band information corresponding to slices, then the UE can select cells based on slice requirements, but the configured frequency band information may become inconsistent with network support after network upgrades, leading to selection of unsuitable cells
Solution Approach 1:
The network performs preliminary actions by providing target operating frequency band and TAI information to the UE in advance (in the rejection message), enabling the UE to select appropriate cells before attempting slice access. This preliminary provision of network support information resolves the contradiction by ensuring the UE has accurate, up-to-date frequency band information that reflects current network capabilities, eliminating the need for the UE to maintain its own potentially outdated configuration.
Solution Approach 2:
The network acts as an intermediary by providing target operating frequency band and TAI information that mediates between the UE's slice requirements and the network's actual support capabilities. This intermediary information allows the UE to select cells that are guaranteed to support the desired slice, resolving the inconsistency between UE configuration and network support without requiring the UE to directly configure frequency band information.
2Adaptability or versatility
If the UE requests required S-NSSAI by carrying requested NSSAI in registration request message, then the UE can indicate slice requirements, but the cell or RAN node may not support the requested S-NSSAI, resulting in access rejection
Solution Approach 1:
The network performs preliminary action by identifying and providing target operating frequency band and TAI information that corresponds to cells supporting the UE's requested S-NSSAI. This preliminary provision of supported cell information ensures that when the UE selects a cell based on this information and retries access, the cell is guaranteed to support the requested slice, thereby resolving the contradiction between slice access capability and access success rate.
3Reliability
If the network provides target operating frequency band and TAI information to the UE, then the UE can select appropriate cells supporting the desired slice, but this requires additional information exchange between network and UE
Solution Approach 1:
The network merges the provision of target operating frequency band and TAI information with the existing slice rejection indication process. By combining these information elements into a single message exchange (providing the frequency band and TAI information along with the slice rejection indication), the solution resolves the contradiction by ensuring network compatibility without requiring separate, complex information exchange procedures.
Data Source
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AI summary
Embodiments of the present application relate to a cell access selection method, a terminal device, and a network device. The method comprises: the terminal device receiving a target operating frequency band and/or a target tracking area identity (TAI); and performing cell selection according to the target operating frequency band and/or the target TAI. According to the embodiments of the present application, no frequency band information corresponding to a slice needs to be configured for a UE, such that the case where a cell selected by the UE does not support the slice which the UE desires to access can be avoided.