CSG Cell Measurement Reporting for Handover Failure Reduction
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Solution Overview
Problem
In wireless communication systems, particularly in 3GPP LTE, the existing methods for reporting measurement results and performing handovers in closed subscriber group (CSG) cells lead to unnecessary handovers due to PCI confusion and lack of preliminary access checks, resulting in a high handover failure rate when micro and macro cells coexist.
Innovation Solution
A method and apparatus for reporting measurement results in a wireless communication system that involves receiving measurement parameters for CSG cells, determining CSG identities, selecting member CSG cells based on signal quality, and transmitting measurement reports to the serving cell, which includes the CSG ID and CGI to prevent PCI confusion and ensure proper handover by performing a preliminary access check.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional handover methods are used in coexisting micro and macro cells, then handover procedures can be executed, but unnecessary handovers occur due to PCI confusion and lack of CSG cell identification
Solution Approach 1:
The patent applies preliminary action by requiring user equipment to acquire CSG identity information (CSG ID) and cell global identity (CGI) before performing handover to CSG cells. The measurement report includes these identifiers in advance, allowing the network to verify CSG cell membership and validity before executing handover, thus preventing unnecessary or failed handovers due to PCI confusion.
Solution Approach 2:
The patent introduces CSG ID and CGI as intermediary identifiers that mediate between the physical cell identity (PCI) and the actual CSG cell identification. These intermediaries allow the network to distinguish between different CSG cells with the same PCI and verify whether a target cell is a valid CSG cell for the user equipment, resolving the PCI confusion problem.
2Measurement precision
If measurement reports include detailed CSG cell information, then accurate CSG cell identification is achieved, but signaling overhead increases
Solution Approach 1:
The patent extracts only the essential identification information (CSG ID and CGI) from the complete cell information set and includes it in the measurement report. This selective extraction provides sufficient information for CSG cell identification and verification without transmitting unnecessary detailed information, thus balancing measurement precision with signaling overhead reduction.
Data Source
AI summary
A method and apparatus of reporting a measurement result in a wireless communication system is provided. An user equipment receives a measurement parameter for measurement of a closed subscriber group (CSG) cell and measures signal quality of at least one CSG cell on the basis of the measurement parameter. The user equipment determines at least one CSG cell's CSG identity (ID) by using system information of the at least one CSG cell and determines at least one member CSG cell having the user equipment as a member thereof from the at least one CSG cell on the basis of the at least one CSG cell's CSG ID. The user equipment selects a member CSG cell to send a measurement report from the at least one member CSG cell, and transmits the measurement report comprising signal quality for the selected member CSG cell.