Base Station Handover NRT Depletion Prevention
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Solution Overview
Problem
When the number of neighboring cells adjacent to a cell generated by a base station device is large, there is a possibility that the neighbor relation table (NRT) used for handover (HO) may be depleted, especially in high altitude platform stations (HAPS) covering vast areas and providing services to multiple business operators.
Innovation Solution
The base station device implements a mechanism to reduce the possibility of NRT depletion by selectively using the NRT for handover operations. It employs a scheme selection unit that chooses between a first scheme, which always uses ReportCGI without registering cell information in the NRT, and a second scheme that uses the NRT when possible, thereby controlling when cell information is registered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station device registers all neighboring cell information in the NRT to enable handover, then handover capability is improved, but the NRT becomes depleted when covering vast areas with many neighboring cells
Solution Approach 1:
The patent applies partial action by selectively registering only certain neighboring cell information in the NRT rather than all neighboring cells. The base station device determines whether to register cell information based on handover conditions, thereby using the NRT capacity efficiently without depleting it when covering vast areas with many neighboring cells.
Solution Approach 2:
The patent implements dynamics by making the NRT registration behavior adaptive and condition-based. The base station device dynamically decides whether to register cell information in the NRT based on handover conditions, allowing the system to adjust its behavior according to current operational requirements rather than following a fixed registration policy.
2Quantity of substance
If the base station device uses ReportCGI always without NRT registration to avoid NRT depletion, then NRT capacity is preserved, but handover operations cannot utilize existing neighbor relation information
Solution Approach 1:
The patent applies dynamics by making the handover method selection adaptive. The base station device dynamically chooses between using NRT-based handover or ReportCGI-based handover based on current conditions such as whether the NRT is full or handover conditions are met, thereby optimizing both NRT capacity preservation and handover efficiency.
Solution Approach 2:
The patent implements parameter changes by modifying the handover decision parameters based on NRT status and handover conditions. The base station device changes the handover method parameter (NRT-based or ReportCGI-based) according to the current state of the NRT and the specific handover requirements, thereby balancing capacity preservation with operational efficiency.
3Reliability
If the base station device registers cell information in the NRT for all neighboring cells, then handover quality is maintained, but the NRT fills up quickly in HAPS covering vast areas
Solution Approach 1:
The patent applies partial action by registering only essential neighboring cell information in the NRT rather than all neighboring cells. The base station device selectively registers cell information based on handover conditions, thereby maintaining handover quality while preventing rapid NRT filling up in HAPS covering vast areas.
Solution Approach 2:
The patent implements preliminary action by pre-determining which neighboring cell information should be registered in the NRT based on handover conditions before actual handover occurs. This allows the system to prepare the NRT with appropriate cell information in advance, ensuring handover quality is maintained while avoiding unnecessary NRT consumption.
Data Source
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AI summary
Provided is a base station device including: a scheme selection unit that selects a scheme of HO from a first scheme not using an NRT and a second scheme using the NRT when receiving a measurement report for HO from a UE; and an HO control unit that, when the first scheme is selected, causes the UE to measure system information of an HO candidate cell, receives an ECGI from the UE, and controls HO of the UE by using cell information of the HO candidate cell received from a core network by using the ECGI, and, when the second scheme is selected, determines whether a PCI of the HO candidate cell is included in the NRT, when the PCI is included, controls the HO of the UE by using cell information corresponding to the PCI, and when the PCI is not included, causes the UE to measure the system information of the HO candidate cell, receives the ECGI from the UE, controls the HO of the UE by using the cell information of the HO candidate cell received from the core network by using the ECGI, and registers the cell information in the NRT.