Selective Antenna Usage for Accurate Handover Decisions
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Solution Overview
Problem
In wireless communication systems, poor call performance occurs when UE antennas are not balanced, leading to handover failures at the cell edge due to weaker signal strength at the primary antenna despite stronger signal measurements from the diversity antenna, causing uplink communication failures.
Innovation Solution
A method and apparatus for selective antenna usage, where metrics such as signal strength and quality are measured for both primary and diversity antennas, and if the primary antenna's metrics fall below thresholds, the diversity antenna's metrics are calculated based on the primary's to ensure accurate measurement reporting, preventing handover to cells with weak primary antenna signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE uses the diversity antenna for measurement reporting when its signal is stronger than the primary antenna, then the measurement accuracy is improved, but the handover decision becomes inaccurate leading to call failures
Solution Approach 1:
The patent inverts the conventional approach by not using the antenna with the strongest signal for measurements, but rather selecting the primary antenna even when its signal is weaker. This inversion prevents the handover failure issue while maintaining measurement reliability through the use of antenna imbalance indicators to compensate for the weaker signal strength.
2Illumination intensity
If the UE camp on a cell based on diversity antenna signal measurements, then the downlink signal quality is improved, but the uplink communication fails due to power limitation on the primary antenna
Solution Approach 1:
The patent performs preliminary assessment of antenna signal characteristics before making handover decisions. By evaluating the primary antenna's signal strength and comparing it with the diversity antenna, the system preemptively identifies scenarios where handover would lead to uplink failure, and adjusts measurement reporting accordingly to prevent such failures before they occur.
3Strength
If the UE reports measurements from the antenna with stronger signal, then the signal strength metric is improved, but the call performance deteriorates due to antenna imbalance
Solution Approach 1:
The patent changes the parameters used for measurement reporting by introducing antenna imbalance indicators and selectively reporting measurements from the primary antenna even when its signal strength is lower. This parameter change allows the system to account for antenna characteristics and prevent handover failures while maintaining accurate measurement reporting.
Data Source
AI summary
An apparatus for selective usage of antennas for measurement purposes is provided. When the signal strength of the primary antenna is less than a signal strength threshold or the signal quality of the primary antenna is less than a signal quality threshold, the apparatus may determine at least one of whether a first difference between the signal strength of the primary antenna and the diversity antenna satisfies a first criteria or whether a second difference between the signal quality of the primary antenna and the diversity antenna satisfies a second criteria. When at least one of the first difference satisfies the first criteria or the second difference satisfies the second criteria, the apparatus may calculate the signal strength and signal quality of the diversity antenna for measurement evaluations and path-loss calculation based on the signal strength and signal quality of the primary antenna.