CSG Cell Measurement Reporting via TA ID and One-Bit Indicator
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Solution Overview
Problem
In wireless communication systems, particularly in E-UTRAN networks, there is a challenge in determining how to accurately and efficiently include private CSG cells in measurement reports from user equipment (UE) to the serving network, especially for UEs without CSG subscription, and how to uniquely identify these cells for effective handover and cell reselection decisions.
Innovation Solution
The method involves determining if an adjacent cell is a private cell and sending a measurement report with an identifier, including a one-bit indicator to indicate CSG membership, allowing UEs to report CSG cells only when authorized and using a shorter CSG TA or L1 cell ID for identification, and employing two measurement report formats to differentiate accessible and non-accessible CSG cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UEs send measurement reports for all adjacent cells including private CSG cells, then the network can make accurate handover decisions, but the signaling overhead increases substantially
Solution Approach 1:
The patent extracts and separates CSG cell measurement reporting from general measurement reporting. UEs only report CSG cell measurements when explicitly triggered by the network, rather than continuously reporting all adjacent cells. This extraction principle reduces signaling overhead by removing unnecessary reporting of CSG cells that UEs cannot access, while maintaining handover accuracy for accessible cells through on-demand reporting.
Solution Approach 2:
The patent implements dynamic reporting behavior where the UE adapts its measurement reporting based on network configuration and CSG subscription status. The network can dynamically configure whether a UE should report CSG cell measurements, and the UE dynamically adjusts its reporting behavior accordingly. This dynamic approach optimizes signaling overhead while ensuring accurate handover decisions when needed.
2Difficulty of detecting and measuring
If the network configures UEs to report CSG cells without subscription, then interferers can be detected, but unauthorized cells are incorrectly reported by default
Solution Approach 1:
The patent implements a feedback mechanism where the network provides CSG whitelist information to UEs, and UEs use this feedback to determine whether to report CSG cell measurements. The network can also provide explicit triggers based on UE reports, creating a feedback loop that enables interferer detection while maintaining authorization accuracy. UEs with CSG subscriptions receive feedback about which cells they are authorized to access, preventing unauthorized cell reports.
3Measurement precision
If two different measurement report formats are used for CSG and non-CSG cells, then cell identification is accurate, but the device complexity increases
Solution Approach 1:
The patent merges CSG cell measurement reporting with standard measurement reporting procedures. Rather than creating entirely separate reporting mechanisms, the patent integrates CSG reporting into the existing measurement report framework, using the same message structures and procedures. This merging approach maintains accurate CSG cell identification through existing identification fields while avoiding the complexity of dual reporting systems.
Data Source
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AI summary
An adjacent cell is determined to be a private cell, and then a measurement report of it that includes an identifier for the private cell is sent from a UE to the UE's serving network node. Methods, apparatus and computer readable media storing a program are detailed. In exemplary non-limiting embodiments: the identifier is at least a TA ID for the private cell's CSG network, where the UE receives the TA ID over a broadcast channel/system information of the serving network node; the TA ID may be a short TA ID received over a primary broadcast channel of the serving network node; the identifier comprises the TA ID and either a LI cell ID or a CSG cell ID; and if the UE is not a member of the CSG network it the measurement report only in response to a command received from the serving network node.