UE Proximity Indication for Private Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
User Equipment (UE) in LTE systems face challenges in determining whether it has access rights to Closed Subscriber Group (CSG) cells without disrupting communication with the serving macro cell, as reading system information from neighbor cells is necessary but can cause communication disruptions, especially in environments with multiple CSG cells.
Innovation Solution
The UE stores a list of authorized CSG cells and determines the physical cell identity of neighbor cells from synchronization signals rather than full system information, comparing it to a mapping list to assess access rights, allowing for accurate proximity indications without disrupting communication with the serving cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE reads system information from neighbor CSG cells to determine access rights, then the accuracy of proximity indication is improved, but communication with the serving macro cell is disrupted
Solution Approach 1:
The patent extracts only the necessary information (physical cell identity from synchronization signals) from the neighbor cell transmissions, rather than reading the complete system information. This allows the UE to determine access rights to CSG cells while maintaining communication with the serving macro cell, thus resolving the contradiction between measurement accuracy and communication reliability
Solution Approach 2:
The network provides the UE with a mapping list in advance that contains the relationship between physical cell identities and CSG identifiers. This preliminary action allows the UE to quickly determine access rights without having to read and process complete system information from neighbor cells, thereby avoiding communication disruptions
2Measurement precision
If the UE reads system information from multiple neighbor CSG cells, then the accuracy of proximity indication is improved, but the time and resources consumed are increased
Solution Approach 1:
The UE extracts only the physical cell identity from synchronization signals of neighbor cells, which are transmitted periodically and require minimal processing time. This extraction approach provides sufficient information for proximity indication accuracy without the time-consuming process of reading complete system information from multiple neighbor cells
Solution Approach 2:
The mapping list is provided in advance by the network, containing pre-computed relationships between physical cell identities and CSG identifiers. This eliminates the need for the UE to perform time-consuming system information reading and processing for each neighbor cell, significantly reducing the time required for proximity determination
3Loss of information
If the UE reads complete system information from neighbor cells, then the information obtained is most accurate, but the device complexity and processing load are increased
Solution Approach 1:
The patent applies information extraction by obtaining only the physical cell identity from synchronization signals, which are specifically designed for this purpose. This minimal information extraction, combined with the pre-provided mapping list, provides sufficient accuracy for proximity indication while dramatically reducing processing complexity compared to reading complete system information
Solution Approach 2:
The network provides a mapping list that acts as a pre-computed reference copy of the relationship between physical cell identities and CSG identifiers. This copying approach allows the UE to determine access rights through simple table lookup rather than complex system information parsing, reducing device processing requirements
Data Source
AI summary
A user equipment UE stores a first list of private cells to which the apparatus is authorized to access (e.g., a CSG whitelist). While under control of a serving first cell, the UE determines from a transmission received from a neighbor second cell a physical cell identity PCI of the neighbor cell, then compares the determined PCI to a stored second list to determine whether the UE is authorized to access the neighbor cell. In one embodiment the second list maps PCIs to CSG IDs; if the determined PCI matches one in the second list the CSG ID is selected and it that matches one in the first list the UE is authorized access. In another embodiment the second list is only the PCI of those CSG cells on the UE's first list that are within the area served by the serving cell, so if the determined PCI matches one in the second list the UE is authorized access.