Wireless Power Transfer Preamble Detection Under Variable Noise
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Solution Overview
Problem
Existing wireless power transfer (WPT) systems face inefficiencies in in-band communication due to improper setting of preamble thresholds, leading to missed data and premature packet detection, especially under varying noise conditions.
Innovation Solution
A device with a controller that measures temporal variations of wireless power and communication signals to dynamically determine thresholds for distinguishing between preamble and data bits, using techniques like amplitude shift keying (ASK) or frequency shift keying (FSK), and adjusts these thresholds based on noise levels to ensure accurate packet identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed preamble threshold is used for packet detection, then the device complexity is reduced, but the reliability of data transmission deteriorates under varying noise conditions
Solution Approach 1:
The patent implements dynamic threshold adjustment by continuously monitoring signal characteristics and adapting the preamble detection threshold based on current noise conditions. The threshold is no longer fixed but dynamically updated to match varying transmission environments, resolving the contradiction between simple fixed thresholds and reliable detection under varying conditions.
Solution Approach 2:
The system employs feedback mechanisms where detected packets and noise levels are fed back to adjust the preamble threshold. This closed-loop approach allows the threshold to adapt to changing conditions while maintaining accurate packet detection, balancing complexity and reliability.
2Productivity
If the preamble threshold is set too low, then premature packet detection occurs, but the productivity of data transmission is reduced due to false detections
Solution Approach 1:
The patent applies partial action by requiring not just any threshold crossing but a sustained threshold crossing over multiple consecutive samples to confirm packet detection. This partial verification approach reduces false detections while maintaining high detection rates for actual packets, balancing productivity and reliability.
3Reliability
If the preamble threshold is set too high, then missed data occurs, but the reliability of packet detection deteriorates
Solution Approach 1:
The system dynamically changes the threshold parameter based on measured noise levels and signal characteristics. By adjusting the threshold to match current conditions rather than using a fixed value, the system maintains high detection accuracy while minimizing data loss across varying transmission environments.
4Reliability
If dynamic threshold adjustment is implemented, then the reliability of in-band communication is improved, but the device complexity increases
Solution Approach 1:
The system implements self-service by automatically monitoring its own performance and adjusting thresholds without external intervention. The device monitors packet detection outcomes and noise levels, then autonomously adjusts its threshold parameters, reducing the need for complex external control mechanisms while maintaining high reliability.
Data Source
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AI summary
A wireless power transfer device may include a circuit couplable with a coil to transmit or receive a first signal providing wireless power through the coil. The first signal may be modulated with second signals. A packet within any of the second signals may include first bits associated with a preamble and second bits associated with data. The device may further include a controller to measure temporal variations of at least one of the first signal, a rectified version of the first signal, or the one or more second signals. The controller may further determine thresholds for distinguishing between bits in the packet based on the temporal variations. The device may further demodulate the signals using the one or more thresholds to identify the preamble of the packet and extract the second bits associated with data from the packet when the preamble of the packet is identified.