RF Tag Power Scheduling via Time-Division Multiplexing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In scenarios with multiple NFC or RFID tags proximate to a single reader antenna, the limited available energy can lead to power failures and communication issues due to high power requirements, especially when tags support input/output operations or power external components.
Innovation Solution
A reader device with a sensing module and scheduler module that selectively activates and deactivates RF antennas and generates a powering schedule based on device characteristics, allowing for controlled electromagnetic field harvesting and active power management across multiple tags.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple tags are powered simultaneously by a single reader antenna, then more tags can communicate their ID, but the limited available energy causes power failures and communication issues
Solution Approach 1:
The patent implements time-division multiplexing where the reader antenna activates tags in periodic time slots rather than simultaneously. Each tag is assigned specific time windows for power harvesting and communication, allowing multiple tags to share the limited energy resource sequentially. This periodic activation pattern prevents power depletion while maintaining communication capability across multiple tags.
Solution Approach 2:
The system dynamically adjusts power allocation and time slot assignments based on real-time conditions such as tag power levels, communication priority, and energy availability. The reader monitors tag status and modifies the powering schedule adaptively, transitioning from static simultaneous powering to dynamic sequential powering to optimize both productivity and reliability.
2Adaptability or versatility
If tags support input/output operations or power external components, then functionality is enhanced, but power requirements increase leading to power failures
Solution Approach 1:
The system performs preliminary power harvesting in dedicated time slots before enabling I/O operations or external component powering. Tags accumulate sufficient energy in advance during harvesting windows, ensuring that when high-power operations are needed, the required energy is already stored. This preliminary energy accumulation allows enhanced functionality without immediate power failure risks.
Solution Approach 2:
The patent applies different power management strategies to different tags based on their specific functionality requirements. Tags with I/O operations receive extended harvesting windows, while tags powering external components are allocated additional energy buffers. This localized quality adjustment ensures each tag receives appropriate energy resources for its specific functional demands.
3Device complexity
If a single antenna serves multiple tags, then device complexity is reduced, but granular power management per tag becomes difficult
Solution Approach 1:
The patent segments the power management control into tag-specific time slots and power allocation windows within the single antenna system. By dividing the time domain into discrete segments assigned to individual tags, the system achieves granular control over each tag's power harvesting and communication without requiring multiple physical antennas. This temporal segmentation enables independent power management for each tag while maintaining hardware simplicity.
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
This solution enables multiple short-range wireless tags to remain powered by optimizing energy harvesting, reducing power consumption, and minimizing communication overhead, while allowing for granular power management per tag rather than per antenna, thus preventing power failures and ensuring continuous operation.
Implementation Method 1
The antenna within an NFC tag is round or rectangular and magnetic induction between the antenna in the tag and an antenna in a proximate NFC reader device provides the energy for the tag to communicate its ID back to the reader device
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A reader device for short-range wireless tags comprises a sensing module coupled to one or more RF antennas. The sensing module is arranged to selectively activate and deactivate individual RF antennas and to read data from a plurality of objects comprising short-range wireless tags which are proximate to an active RF antenna. A scheduler module within the reader device is arranged to obtain device characteristics for the plurality of objects based at least in part on data read by the sensing module and then to generate a powering schedule for the plurality of objects based on the device characteristics. The generated powering schedule is then implemented by the sensing module.