Cell Selection Using Signal Dispersion in Wireless Systems
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Solution Overview
Problem
Beamforming in wireless communication systems complicates the analysis of which candidate cell a wireless device should target for a cell change when the signal quality of the serving cell degrades, leading to increased cell changes and signaling overhead.
Innovation Solution
Selecting the target cell based on the dispersion of received signal measurements across its transmit beams, favoring cells with lower dispersion for more robust signal performance and reduced cell changes, using metrics such as variance or standard deviation, and considering beam configuration information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamforming is employed to amplify transmitted signals in selected directions, then signal performance is improved, but cell selection complexity increases due to multiple transmit beams per cell
Solution Approach 1:
The patent introduces a new parameter - dispersion measure of received signal measurements across multiple transmit beams - to characterize cell signal quality. This parameter transforms the complex multi-beam evaluation into a single metric that captures the robustness of cell coverage, enabling simpler cell selection decisions while maintaining beamforming benefits
Solution Approach 2:
The dispersion measure acts as an intermediary metric between the raw received signal measurements on multiple beams and the final cell selection decision. Instead of directly comparing multiple beam measurements across cells, the patent uses this intermediary statistic to simplify the selection process while preserving the reliability improvements from beamforming
2Reliability
If cell change decisions are made based on signal quality degradation, then connection reliability is maintained, but the number of cell changes increases leading to signaling overhead
Solution Approach 1:
The patent changes the parameter used for cell change triggering from simple signal quality thresholds to dispersion-based metrics. By monitoring changes in dispersion rather than absolute signal levels, the system can maintain connection reliability while reducing unnecessary cell changes, thereby lowering signaling overhead
Solution Approach 2:
The patent performs preliminary evaluation of dispersion characteristics before triggering cell changes. By assessing the dispersion measure in advance and comparing it against selection criteria, the system可以避免 premature or unnecessary cell changes, reducing the frequency of cell change signaling while maintaining reliable connections
Data Source
AI summary
A wireless device (16) is configured for use in a wireless communication system (10). The wireless device (16) in this regard is configured to obtain, for each of one or more cells, information derived from a measure of dispersion of the values of received signal measurements respectively performed by the wireless device (16) on different transmit beams of the cell. The wireless device (16) is also configured to use the obtained information to select, or to assist network equipment (500A, 500B) to select, from the one or more cells a target cell to which the wireless device (16) is to change. The wireless device (16) is further configured to perform a cell change to the selected target cell.