RF Path Loss Determination with Hysteresis Edge Detection
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Solution Overview
Problem
Current methods for measuring radio frequency (RF) receiver sensitivity in mobile wireless communications systems, such as GSM devices, are time-consuming and lack accuracy due to the need to scan numerous channels and report receiver accuracy levels with limited precision, especially in determining path loss and bit error ratio (BER) across multiple frequency bands.
Innovation Solution
A method and system that utilize a channel information-based search approach, employing a base station emulator and test controller to determine RF path loss by sweeping RF power values and generating RSSI values, and applying a least squares algorithm with spline fitting to create a fast sensitivity search curve, allowing for predictive transmit level changes and improved accuracy in measuring conducted and radiated receiver sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional semi-intuitive methods are used to scan every channel of a GSM mobile phone, then measurement accuracy is maintained, but measurement time increases significantly
Solution Approach 1:
The patent performs preliminary actions by pre-calculating path loss values for multiple channels based on frequency band characteristics before actual sensitivity measurements. This allows the system to skip unnecessary channel scanning and directly measure only the necessary channels, significantly reducing measurement time while maintaining accuracy through the pre-established path loss models.
Solution Approach 2:
The patent creates a virtual copy of the channel scanning process by using mathematical models and pre-calculated path loss values to represent multiple channels simultaneously. Instead of physically scanning each channel, the system uses these models to predict and compare channel performance, achieving accurate measurements across all channels without the time cost of traditional sequential scanning.
2Productivity
If automated methods with binary-tree search methodology are used, then measurement speed increases, but measurement precision deteriorates due to random or binary-tree search patterns
Solution Approach 1:
The patent implements feedback mechanisms where the system continuously monitors RSSI (Received Signal Strength Indicator) values during path loss measurements and adjusts the search methodology accordingly. This feedback loop allows the system to identify the optimal measurement path dynamically, ensuring both speed and precision by focusing measurement efforts on channels that require detailed analysis while skipping channels with predictable characteristics.
Solution Approach 2:
The patent changes the search parameters from fixed binary-tree patterns to adaptive parameter adjustment based on observed RSSI characteristics. The system modifies measurement steps and channel selection criteria in real-time based on the specific channel conditions and device responses, achieving both rapid measurement completion and high precision through dynamically optimized parameters.
3Measurement precision
If RF power values are swept at fine granularity to determine hysteresis edges, then measurement precision improves, but measurement time increases
Solution Approach 1:
The patent segments the RF power sweeping process into distinct phases: an initial coarse sweep to identify approximate hysteresis edges, followed by targeted fine-grained sweeping only in the critical regions where transitions occur. This segmentation allows the system to maintain high precision for hysteresis edge detection while minimizing overall measurement time by avoiding unnecessary fine-grained sweeping across the entire power range.
Solution Approach 2:
The patent applies dynamic adjustment to the sweeping process, changing the granularity of RF power steps based on the current measurement state. The system automatically transitions from coarse to fine sweeping steps when approaching hysteresis edges, and can skip fine sweeping when stable regions are detected. This dynamic approach ensures precise hysteresis detection only where needed, significantly reducing total measurement time.
Data Source
AI summary
A test method is for determining RF path loss between an RF source and an RF receiver. The RF source may transmit RF power values at a relatively fine granularity, and the RF receiver may generate RSSI values at a relatively coarse granularity and have an unknown hysteresis about each transition between adjacent RSSI values. Hysteresis edges may be determined about a given RSSI value transition at the RF receiver by sweeping RF power values transmitted from the RF source in increasing and decreasing directions. A relationship between the relatively fine granularity RF power values and the relative coarse granularity RSSI values may be determined using the hysteresis transition edges. The RF path loss for a given channel may be determined based upon a given RSSI at a given RF power value and the relationship between the relatively fine granularity RF power values and the relative coarse granularity RSSI values.