Mobile Terminal CSG Search Triggering via Position Change
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Solution Overview
Problem
Current methods for mobile radio terminals to identify access points in a closed group cellular mobile radio network are inefficient due to high operational effort, inaccuracy, and the inability to maintain relationships between macro cells and CSG cells, especially when there are many CSG cells or when network customers install CSG cells autonomously, leading to excessive energy consumption and user delays.
Innovation Solution
A method where the mobile radio terminal stores data on neighboring cells and only initiates a search for CSG cells when its geographical position changes significantly within the range of known neighboring cells, reducing unnecessary searches and improving the accuracy of the search area by using timing advance values, synchronization information, and signal reception quality as triggering criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If macro cells broadcast information about neighboring CSG cells and mobile radio terminals use this as a basis for search, then the search coverage is expanded, but the operational effort and energy consumption increase significantly
Solution Approach 1:
The mobile radio terminal proactively determines and stores a list of neighboring macro cells before actually needing to search for CSG cells. This preliminary action allows the terminal to have ready-made search targets stored in memory, eliminating the need for continuous broadcasting and reducing energy consumption while maintaining comprehensive search coverage.
Solution Approach 2:
The mobile radio terminal autonomously determines neighboring macro cells using its own measurement capabilities (signal strength, timing advance values) without requiring network broadcasting. The terminal serves itself by independently building and maintaining its own neighborhood information, reducing the operational burden on the network while ensuring accurate and up-to-date search information.
2Measurement precision
If the mobile radio terminal periodically repeats the search at short time intervals, then the search accuracy is improved, but the energy requirement increases
Solution Approach 1:
The search triggering mechanism is made dynamic rather than static periodic. The terminal continuously monitors triggering criteria (signal strength changes, timing advance variations, position changes) and initiates searches only when these dynamic conditions indicate a potential CSG cell becomes available. This dynamic approach maintains high search accuracy while avoiding unnecessary periodic searches that waste energy.
Solution Approach 2:
The system uses feedback from continuous monitoring of radio conditions (signal strength, timing advance values from macro cells) to intelligently trigger searches. When the feedback indicates that the terminal has moved into a region where CSG cells might be present (based on changes in macro cell signal characteristics), a search is initiated. This feedback-driven approach ensures accurate timing of searches without wasteful periodic repetitions.
3Productivity
If the search is restricted to the region surrounding the CSG cell, then the search scope is reduced, but the definition of region encompasses multiple macrocells making it impossible to maintain relationships
Solution Approach 1:
The patent extracts the neighborhood information maintenance task from the network operator and transfers it to the individual mobile radio terminals. Each terminal independently determines and maintains its own list of neighboring macro cells relevant to CSG cell searches. This extraction eliminates the complexity of network-wide region management while improving search efficiency, as each terminal has personalized, accurate neighborhood information without requiring the network to maintain complex region-CSG cell relationships.
Data Source
AI summary
The invention relates to a method for identifying access points for a closed group of mobile radio devices to a cellular mobile radio network, wherein the use of said access points is authorized only for the closed group of mobile radio devices, wherein the data from a neighboring cell are transmitted to a mobile radio device checked into said cell by a cell forming such an access point, and/or a search for currently receivable neighboring cells is performed by the mobile radio device checked into said cell, the data from the neighboring cell are stored at least temporarily in the mobile radio device, and a search for the access point is initiated if the mobile radio device is present within range of one or more neighboring cells, wherein, in case the access point is not found, a renewed search for the access point is performed by the mobile radio device if the geographic position of the mobile radio device has changed significantly relative to a previous position, within the range of the neighboring cells.