Cell Selection Prioritization for LADN Service Continuity
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Solution Overview
Problem
In 5G systems, user equipment (UE) faces challenges in selecting cells that provide local area data network (LADN) services due to limitations in existing cell selection criteria, leading to service discontinuity, increased signaling overhead, and inability to access multiple LADN services, especially when moving between cells or out of service areas.
Innovation Solution
Implement methods and systems to prioritize cell selection and reselection based on the availability of LADN services, utilizing LADN information to identify and prioritize cells that support intended services, enabling seamless handovers and simultaneous service access from multiple cells, and managing data buffering to minimize signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE performs cell selection using existing criteria (RSRP/RSRQ), then signal strength is maximized, but LADN service availability is lost
Solution Approach 1:
The patent applies local quality by making cell selection criteria specific to LADN services rather than universal. The UE determines LADN service areas and identifies cells within those areas, then applies enhanced selection criteria (including LADN support verification) only to cells within LADN service areas. This allows the system to maintain simple RSRP-based selection for general connectivity while applying quality-specific filtering for LADN service access.
Solution Approach 2:
The patent implements preliminary action by having the UE obtain LADN service area information from the network before performing cell selection. The UE proactively identifies which cells provide LADN services and stores this information, then uses it to guide subsequent cell selection decisions. This preliminary preparation ensures that when the UE needs to select a cell for LADN service, it can immediately apply the appropriate criteria without delay.
2Reliability
If UE camps on cell with higher RSRP, then connection quality is improved, but LADN service continuity is interrupted
Solution Approach 1:
The patent changes the cell selection parameters by introducing LADN service availability as a primary selection criterion alongside or above traditional signal strength parameters. When multiple cells are available, the UE prioritizes cells that both provide LADN services and meet minimum signal quality thresholds. This parameter change ensures service continuity by preventing handovers to cells that would interrupt LADN access, even if those cells have slightly lower signal strength.
Solution Approach 2:
The system implements feedback mechanisms where the network provides LADN service area information to the UE, and the UE uses this feedback to adjust its cell selection behavior. The UE continuously monitors which cells are within LADN service areas and uses this information to guide handover decisions, ensuring that handovers maintain LADN service continuity while still considering signal quality.
3Adaptability or versatility
If UE stores only first 8 LADN DNN values, then memory usage is reduced, but access to additional LADN services is blocked
Solution Approach 1:
The patent changes the storage capacity parameter for LADN DNN values from the traditional limit of 8 values to an expanded capacity that can accommodate more DNN values. This parameter change allows the UE to store and access a larger number of LADN service identifiers, thereby increasing adaptability and versatility for accessing multiple LADN services simultaneously or sequentially without being constrained by the previous storage limitation.
4Reliability
If UE frequently activates and deactivates LADN PDU, then service area boundary compliance is maintained, but signaling overhead increases
Solution Approach 1:
The patent applies preliminary action by having the UE obtain and store LADN service area information (TAI lists) in advance from the network. The UE uses this pre-obtained information to proactively determine when it is approaching or leaving LADN service areas, allowing it to prepare for PDU activation or deactivation before actually crossing boundaries. This reduces reactive signaling and allows for more efficient resource management.
Solution Approach 2:
The UE implements self-service by autonomously monitoring its location relative to LADN service areas using the stored TAI information and automatically making decisions about PDU activation/deactivation based on its own determined location status. This self-service approach reduces the need for continuous network signaling and allows the UE to manage its own LADN service access efficiently based on local information.
Data Source
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AI summary
Methods and systems for prioritizing cell selection for availing LADN services. A UE prioritizes cells for selection based on availability of LADN services in the cells. For handover, a base station of a cell, providing LADN services to the UE, prioritizes target cells that provide LADN services that are being currently availed by the UE for ensuring LADN service continuity. The base station initiates addition of secondary cells that provide additional LADN services that are intended by the UE. The UE can predict if a paging message is relevant to a LADN service and send serving requests to the serving cell or other cells to avail the LADN service. The UE detects relay UEs providing LADN services and prioritizes the relay UEs for selection based on availability of LADN services. The UE buffers data if the UE is located at an edge of a LADN service area.