Slice-Aware Cell Reselection Priorities for 5G Service Continuity
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Solution Overview
Problem
Existing cell reselection mechanisms in 5G networks with network slicing are inadequate, as they do not effectively prioritize cell selection based on specific network slices, leading to potential suboptimal cell choices that may not support the required services.
Innovation Solution
Implementing a method for cell reselection that identifies and prioritizes network slices using Single-Network Slice Selection Assistance Information (S-NSSAI) and Network Slice Access Stratum Group (NSAG) to determine slice-specific cell reselection priorities, which are communicated to the user equipment (UE) for informed decision-making.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a UE is simultaneously connected to multiple network slices, then service diversity and network versatility are improved, but cell reselection complexity increases because the UE must evaluate multiple slice-specific priorities
Solution Approach 1:
The patent segments cell reselection priorities by network slice, introducing slice-specific priorities (PSCell) for each S-NSSAI. This allows the UE to evaluate cell suitability independently for each slice it needs to access, rather than using a single generic priority. The segmentation enables the UE to handle multiple slices simultaneously while maintaining clear, slice-specific reselection criteria for each.
Solution Approach 2:
The patent adds a new dimension to cell reselection by introducing a slice identifier (S-NSSAI) as a key parameter alongside traditional cell priorities. This creates a two-dimensional priority structure where priorities are defined both by frequency/cell and by network slice. The UE uses this dimensional extension to select cells that satisfy specific slice requirements while maintaining overall reselection efficiency.
2Reliability
If cell reselection priorities are assigned based on slice-specific requirements, then service continuity and reliability are improved, but signaling overhead and network element complexity increase
Solution Approach 1:
The network element performs preliminary actions by pre-calculating and storing slice-specific cell reselection priorities for each S-NSSAI before the UE needs them. When a UE requests access to specific slices, the network element already has the priority information ready, eliminating the need for complex real-time calculations during cell reselection events. This preliminary preparation reduces both signaling overhead and operational complexity.
Solution Approach 2:
The network element creates and maintains copies of cell reselection priority information for each network slice (S-NSSAI). Instead of computing priorities dynamically for each UE request, the system pre-generates and stores multiple copies of priority data corresponding to different slice configurations. This copying approach allows rapid retrieval and reduces the computational burden on the network element during actual cell reselection operations.
3Measurement precision
If the network provides detailed slice-specific cell reselection information, then UE cell selection accuracy is improved, but information processing load and messaging overhead increase
Solution Approach 1:
The patent applies local quality by providing cell reselection priority information specifically tailored to each slice (S-NSSAI) that the UE needs to access. Rather than broadcasting generic priority data for all slices, the network element delivers targeted priority information only for the relevant slices. This localized approach improves cell selection accuracy for each specific slice while minimizing unnecessary information transmission.
Solution Approach 2:
The network element implements partial action by providing slice-specific reselection priorities only for the subset of slices that the UE actually needs to access, rather than providing information for all possible slices. The UE receives priority data for its specific S-NSSAI(s) of interest, which reduces the overall volume of signaling information while still achieving accurate cell selection for the required services.
Data Source
AI summary
A network element of a wireless communication network is communicatively coupled to a user equipment and identifies a list of one or more features provided by the wireless communication network. Each feature on the list is related to at least one of a service capability of the UE and a service request of the user equipment. The network element determines a priority order among the one or more features related to cell reselection and assigns cell reselection priorities for the user equipment according to the priority order, for example by indicating cell reselection priorities or a priority order of features and corresponding cell reselection mechanisms to the user equipment. The user equipment performs cell reselection by applying a cell reselection mechanism and cell reselection priority in accordance with the indication of the network element.