UE Configured Grant Validation Across Cells for Inactive-State SDT
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Solution Overview
Problem
The efficacy of configured grant (CG)-based small data transmission (SDT) in 5G or NR communication systems is reduced for moving UEs in an inactive state due to invalidation of CG-SDT configurations when cell reselection occurs, as NR cells have smaller coverage areas, leading to increased signaling overhead and reduced load balancing.
Innovation Solution
A method for a UE to preconfigure multiple CG-SDT configurations associated with a list of cells, verifying the camping cell's validity before triggering SDT, and utilizing the CG resource when the validation condition is satisfied, allowing continued use across multiple cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If CG-SDT configuration is restricted to only the last serving cell, then the configuration validation is simple, but the efficacy is reduced for moving UEs due to frequent cell reselection in NR
Solution Approach 1:
The patent segments the CG-SDT configuration by associating it with multiple specific cells rather than a single last serving cell. The configuration includes a list of candidate cells, and the UE validates whether the current camping cell matches any cell in this list, thereby resolving the contradiction between simple validation and multi-cell efficacy.
Solution Approach 2:
The CG-SDT configuration is designed to be universally applicable across multiple cells by including a list of candidate cells. This allows the same configuration to serve multiple functions: it remains valid whether the UE camps on any of the listed cells, thus improving productivity for moving UEs while maintaining manageable validation complexity through the predefined list approach.
2Device complexity
If CG-SDT configuration becomes invalid upon cell reselection, then the configuration remains simple to manage, but signaling overhead increases due to frequent connection establishment
Solution Approach 1:
The patent applies preliminary action by pre-configuring a list of candidate cells in the CG-SDT configuration before the UE enters inactive state. This preliminary setup allows the UE to perform SDT without establishing a connection when camping on any of the pre-configured cells, thereby reducing signaling overhead while keeping configuration management simple through the predefined cell list.
Solution Approach 2:
The configuration is effectively copied across multiple cells by including all candidate cell identifiers in the CG-SDT configuration. Instead of creating separate configurations for each cell, the patent uses a single configuration that references multiple cells, reducing configuration management complexity while preventing signaling overhead through valid SDT opportunities.
3Area of stationary object
If NR cells have smaller coverage areas, then the network coverage is more precise, but cell reselection occurs more frequently for moving UEs
Solution Approach 1:
The patent introduces dynamics by allowing the CG-SDT configuration to be associated with multiple cells rather than being static to a single last serving cell. The configuration dynamically remains valid as the UE moves between any of the listed candidate cells, accommodating the frequent cell reselection characteristic of small NR cells while maintaining transmission efficiency.
Solution Approach 2:
The patent changes the parameter of configuration validity from being tied to a single cell identifier to being tied to a set of cell identifiers. This parameter change allows the CG-SDT configuration to remain valid across multiple smaller NR cells, thereby maintaining small data transmission efficiency despite frequent cell reselection caused by smaller coverage areas.
Data Source
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AI summary
The disclosure is directed to a method used by a UE to preconfigure a resource for small data transmission in an inactive state and a user equipment using the same method. In one of the exemplary embodiments, the disclosure is directed to a method used by a UE to preconfigure a resource for small data transmission in an inactive state. The method would include not limited to: receiving a CG configuration which is for a small data transmission before entering an inactive state; verifying a CG resource of a camping cell associated with the CG configuration by determining whether the camping cell satisfies a validation condition before triggering a SDT procedure, wherein the CG configuration comprises a list of CG configurations associated with a list of cells; and utilizing the CG resource for the SDT procedure when the validation condition has been determined as being satisfied.