Portable RFID Reader Caching for Power Reduction
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Solution Overview
Problem
Existing portable devices with RFID reading functionality unnecessarily re-read RFID tags when a read command is re-entered within a predetermined time, leading to increased power consumption and inefficiency, especially in high frequency systems with limited battery capacity.
Innovation Solution
A portable device equipped with an RFID reader, memory, and controller that caches previously read RFID tag information, determining its validity based on time and location, and only re-detects the tag if it has changed or if the device has moved out of range, thereby reducing unnecessary readings and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the portable device re-reads RFID tags when a read command is re-entered within a predetermined time, then the tag information is always up-to-date, but the power consumption increases significantly
Solution Approach 1:
The system performs preliminary reading of RFID tags and stores the tag information in memory before the user re-enters the read command. When a read command is re-entered within the validation time period, the system retrieves the pre-stored tag information from memory instead of performing another reading operation, thereby avoiding unnecessary power consumption while ensuring the information remains valid.
Solution Approach 2:
The system uses its own stored memory to serve the tag information retrieval need. By caching the tag information locally in memory after the initial read operation, the system can serve subsequent read commands within the validation period without requiring external re-reading operations, making the system self-sufficient and reducing energy expenditure.
2Length of stationary object
If the portable device continuously transmits electromagnetic waves to read RFID tags, then the reading distance is maintained, but the battery capacity depletes faster
Solution Approach 1:
Instead of continuously transmitting electromagnetic waves, the system performs periodic reading operations only when necessary. The RFID reader transmits electromagnetic waves to read tags initially, stores the information, and then stops transmitting until a new read command is received within the validation time period. This periodic action maintains reading capability while significantly reducing energy consumption compared to continuous operation.
Solution Approach 2:
The system extracts and stores the essential tag information in memory after the initial reading operation. By extracting only the necessary tag data and storing it locally, the system eliminates the need for continuous electromagnetic wave transmission to maintain reading capability, thereby preserving battery capacity while retaining access to tag information.
3Productivity
If the portable device validates tag information based on time and location, then unnecessary readings are reduced, but the system complexity increases
Solution Approach 1:
The system implements a feedback mechanism where the controller continuously monitors the validation time period and compares it with the current time. When the elapsed time exceeds the validation time, the system automatically determines that the cached tag information is no longer valid and triggers a new reading operation. This feedback loop maintains reading efficiency by preventing unnecessary readings within the validation period while managing system complexity through automated time-based decision making.
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 approach minimizes repeated RFID tag readings, conserves power, and provides timely and accurate tag information to applications by using cached data when the tag and device remain within predetermined validation criteria.
Implementation Method 1
an RFID reader chip of the portable device is driven to transmit electromagnetic waves. The RFID tags within a predetermined distance from the portable device generate induction current when receiving the electromagnetic waves.
Implementation Method 2
The IC of the RFID tag is driven by the generated induction current, to transmit predetermined tag information.
Data Source
AI summary
A portable device includes an RFID reader for detecting a tag information of an RFID tag, a memory for storing the tag information detected by the RFID reader, and a controller. When a read command for the RFID tag is input and the tag information is valid, the controller controls the RFID reader to retrieve the tag information of the memory. If the tag information is invalid, the controller controls the RFID reader to re-read the RFID tag. The controller can determine whether the tag information is valid using the time and location. Because unnecessary operation can be omitted to read tags, power consumption is reduced and tag information check time is shortened.