RACH Measurement Reporting with Threshold Filtering
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Solution Overview
Problem
In mobile communication systems, the existing method of reporting inter-frequency measurement results via the Random Access Channel (RACH) message leads to excessive signaling overhead due to the inclusion of measurement results for non-used frequencies, even when the channel states are poor, causing unnecessary transmission requests and increased load on the uplink.
Innovation Solution
A method and apparatus that minimize the information format of measurement reports by only including inter-frequency cell IDs with signal strengths exceeding a threshold in the RACH message, reducing unnecessary reporting and signaling overhead, where the UE sets a threshold for inter-frequency measurement reporting and transmits only the relevant measurement results for non-used frequency bands with better signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If measurement results for all non-used frequency cells are included in the RACH message, then the system can obtain complete measurement information for handover decisions, but the signaling overhead increases excessively
Solution Approach 1:
The patent extracts only the essential measurement information (cell IDs of cells with signal strength exceeding threshold) from the complete measurement data, excluding redundant information about cells with poor signal quality. This selective extraction reduces the RACH message size while preserving the information necessary for handover decisions.
Solution Approach 2:
The patent applies different reporting rules to different frequency cells based on their local signal quality characteristics. Cells with signal strength above a threshold are reported with full detail (cell ID), while cells below the threshold are excluded from reporting, creating a quality-based differentiation in the measurement report.
2Loss of information
If measurement results for non-used frequencies are transmitted regardless of channel state, then all available measurement data is provided to the system, but unnecessary transmission requests increase the uplink load
Solution Approach 1:
The patent performs preliminary filtering of measurement results before inclusion in the RACH message by comparing signal strengths against a threshold. This preliminary action identifies and excludes measurements that would not contribute meaningfully to handover decisions, reducing unnecessary uplink transmissions.
Solution Approach 2:
Instead of transmitting all measurement data (excessive action), the patent transmits only the subset of measurements that exceed the signal strength threshold (partial action). This partial transmission approach provides sufficient information for system decisions without the overhead of complete data transmission.
Data Source
AI summary
A user equipment (UE) is provided which reduces uplink signaling overhead in the process of reporting inter-frequency measurement results over a RACH. For measurement reporting, the UE receives an SIB including a cell information list for non-used frequency cells and a threshold from an RNC, compares signal strengths of signals received from the non-used frequency cells with the threshold, and acquires at least one inter-frequency cell ID indicating at least one non-used frequency cell having signal strength exceeding the threshold from the cell information list. The at least one inter-frequency cell ID is included in a RACH message as measurement result information for the at least one non-used frequency cell, and transmitted to the RNC. The RNC determines that the cell corresponding to the inter-frequency cell ID has signal strength exceeding the threshold.