Backscatter Device Charging Frames for Low-Interference Power Transfer
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Solution Overview
Problem
Ambient Power Backscatter Devices (BKDs) face challenges in receiving sufficient energy for operation due to the limitations of typical charging frames, which often result in interference and inadequate power supply, especially for passive BKDs that rely on radio frequency signals for charging.
Innovation Solution
A new charging frame structure and scheme are introduced, including a Physical Layer Protocol Data Unit (PPDU) with specific fields like Legacy Short Training Field, Legacy Long Training Field, Charge Signal Field, and a modulated payload, designed to minimize interference and provide sufficient energy to BKDs, allowing for incremental power transfer and efficient charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If typical charging frames are used for AMP BKDs, then the charging process is simple, but the devices receive insufficient energy and experience interference
Solution Approach 1:
The charging frame is segmented into distinct functional fields including Legacy Short Training Field, Legacy Long Training Field, Charge Signal Field, and modulated payload. This segmentation allows each field to serve specific purposes: training fields for signal calibration, charge signal field for power transfer, and payload for data transmission, thereby reducing interference while ensuring sufficient energy delivery to passive BKDs
Solution Approach 2:
A Charge Signal Field is introduced as an intermediary component between the traditional WiFi frame structure and the power transfer mechanism. This intermediary field specifically handles the power delivery function, separating it from data transmission functions and reducing mutual interference, while enabling reliable energy transfer to ambient power devices
2Adaptability or versatility
If standard WiFi frames are used, then compatibility is maintained, but power transfer to passive devices is insufficient
Solution Approach 1:
The charging frame structure is designed to be multi-functional, maintaining compatibility with standard WiFi protocols through inclusion of legacy training fields and signal fields, while simultaneously providing enhanced power transfer capabilities through the Charge Signal Field and modulated payload. This allows the same frame structure to serve both communication and power delivery functions for both traditional and ambient power devices
3Power
If charging frames are extended to provide more energy, then power supply improves, but interference increases
Solution Approach 1:
The extended charging frame is segmented into specialized fields where the Charge Signal Field handles power transfer and the modulated payload handles data transmission. This segmentation allows the frame to be extended in duration and energy content without proportionally increasing interference, as each segment operates with optimized parameters for its specific function
Solution Approach 2:
The charging process uses periodic transmission of structured charging frames with alternating phases of energy delivery and signal calibration. The Legacy Long Training Field and Charge Signal Field are transmitted in periodic intervals, allowing the system to deliver extended power supply while using the training fields to periodically recalibrate and minimize interference buildup
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution enables effective charging of BKDs by reducing interference and ensuring sufficient energy transfer, allowing them to operate and transmit data reliably, even for passive devices without a power source, by structuring the charging frame to maximize energy delivery and adapt to the device's energy needs.
Implementation Method 1
passive BKDs that rely on radio frequency signals for charging
Implementation Method 2
Backscatter Devices (BKDs)
Data Source
AI summary
Charging for Ambient Power (AMP) devices and, in particular, AMP Backscatter Devices (BKDs) may be provided. AMP device charging may include a transmitting device transmitting an initial charging frame, the initial charging frame comprising a payload for charging. The transmitting device may detect a BKD in response to transmitting the initial charging frame. The transmitting device may then determine a new payload for a new charging frame to charge the BKD and transmit the new charging frame to charge to the BKD.