UE Slice Reselection Using Pending NSSAI to Avoid Unneeded NSSAA
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Solution Overview
Problem
The current 3GPP specifications lack clarity regarding Network Slice Based Cell Reselection, leading to inefficient network resource usage and service degradation due to unresolved situations where UEs maintain network slices of no interest, causing unnecessary resource allocation and delayed service activation.
Innovation Solution
A method for User Equipment (UE) to communicate with a communication apparatus to indicate disinterest in specific Network Slice Selection Assistance Information (S-NSSAI) and abort the corresponding authentication and authorization procedures, allowing for more efficient resource management and service activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UE maintains S-NSSAI in Pending NSSAI during Network Slice Based Cell Reselection, then the UE can potentially access additional network slices, but network resources are wasted on unnecessary authentication procedures and resource allocation
Solution Approach 1:
The UE performs Network Slice Based Cell Reselection using Pending NSSAI before NSSAA procedure completion, proactively preparing for potential slice access. The UE sends Registration Request with Requested NSSAI including S-NSSAI from Pending NSSAI, and the network initiates NSSAA procedure in advance. This allows the UE to evaluate available slices and select optimal cells beforehand, while the network prepares authentication resources efficiently.
Solution Approach 2:
The system dynamically manages the transition of S-NSSAI between Pending NSSAI and Allowed NSSAI based on NSSAA procedure status. The UE can include S-NSSAI from Pending NSSAI in Requested NSSAI during cell reselection, and the network dynamically updates the UE's allowed slices upon successful NSSAA completion, moving from a static to dynamic slice management approach that adapts to real-time authentication status.
2Loss of energy
If the UE waits for NSSAA procedure completion before cell reselection, then network resources are used efficiently, but service activation is delayed
Solution Approach 1:
The UE performs cell reselection based on Pending NSSAI before NSSAA procedure completion. The NAS layer informs the AS layer of NSAG and priorities based on Pending NSSAI, enabling the UE to select optimal cells in advance. The network simultaneously initiates NSSAA procedure, so that when authentication completes, the UE is already positioned in a cell that supports the required slices, eliminating waiting time.
Solution Approach 2:
The UE maintains continuous cell reselection capability throughout the NSSAA procedure by using Pending NSSAI. The NAS layer continuously provides NSAG information to the AS layer based on Pending NSSAI status, ensuring uninterrupted mobility management. This allows the UE to perform useful cell evaluation and selection actions continuously rather than pausing for NSSAA completion.
3Adaptability or versatility
If the UE includes S-NSSAI from Pending NSSAI in Requested NSSAI during Registration, then the UE can access new slices, but the NSSAA procedure becomes meaningless and causes network load
Solution Approach 1:
The system dynamically determines whether to include S-NSSAI from Pending NSSAI in Requested NSSAI based on the current cell's slice support capability. The UE checks if the current cell supports the S-NSSAI, and only includes it in Requested NSSAI if the cell provides appropriate support (e.g., matching NSAG). This dynamic filtering prevents meaningless NSSAA procedures while maintaining flexible slice selection where applicable.
Solution Approach 2:
The UE applies different handling to different S-NSSAI based on local cell conditions. For S-NSSAI that the current cell supports (matching NSAG), the UE includes them in Requested NSSAI and performs cell reselection. For S-NSSAI not supported by the current cell, the UE excludes them from Requested NSSAI, avoiding unnecessary NSSAA procedures. This localized quality control optimizes network processing efficiency.
Data Source
AI summary
An example aspect of this disclosure includes a method of a User Equipment (UE). The method includes communicating with a communication apparatus. The method includes sending, to the communication apparatus, first Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI).