NFC Reader Dynamic Power Control via Load Modulation
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Solution Overview
Problem
Conventional NFC cards exhibit significant differences in power consumption and modulation degree, leading to potential performance degradation in short-range wireless communication due to inappropriate power supply, which existing methods, such as impedance variation detection, cannot effectively address.
Innovation Solution
A communication apparatus and method that include a reception circuit capable of measuring the modulation degree of signals transmitted via load-modulation in short-range wireless communication, allowing for dynamic adjustment of transmission power to match the characteristics of each card.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transmission power is increased to ensure sufficient power supply to NFC cards, then communication reliability is improved, but power consumption and potential performance degradation occur when cards have different characteristics
Solution Approach 1:
The patent implements dynamic transmission power adjustment by continuously monitoring the modulation degree of signals received from NFC cards. The reader/writer changes transmission power levels based on real-time feedback about card characteristics, transitioning from a static power supply approach to a dynamic one that adapts to each card's specific requirements, thereby resolving the contradiction between ensuring sufficient power and avoiding excessive power consumption.
Solution Approach 2:
The patent employs feedback mechanisms where the reader/writer measures the modulation degree of load-modulated signals from NFC cards and uses this information to adjust transmission power. This closed-loop control system allows the reader/writer to receive feedback about card characteristics and modify power supply accordingly, optimizing both communication reliability and power consumption efficiency.
2Device complexity
If fixed transmission power is used for all NFC cards, then device complexity is reduced, but communication performance deteriorates due to large differences in card characteristics
Solution Approach 1:
The patent enables NFC cards to self-identify their characteristics through load modulation, where each card naturally exhibits its unique electrical characteristics (such as modulation degree) when receiving power. The reader/writer detects these self-exhibited characteristics and adjusts power accordingly, allowing cards to effectively 'service themselves' by revealing their requirements without needing explicit identification mechanisms, thus balancing complexity and performance.
Solution Approach 2:
The patent changes the operational parameter of transmission power based on detected card characteristics. By monitoring modulation degree and adjusting power levels dynamically, the system transitions from a fixed parameter approach to a variable parameter approach, optimizing communication performance for different card types while maintaining manageable system complexity through focused measurement and adjustment.
3Power
If impedance variation detection method is used to monitor transmission output, then power adjustment is achieved, but the method is ineffective when impedance change is small on the reader/writer side
Solution Approach 1:
The patent introduces modulation degree as an intermediary measurement parameter that provides more sensitive and precise information about card characteristics than direct impedance measurement. By measuring the modulation degree of load-modulated signals rather than directly measuring impedance changes, the system gains a more reliable indicator for power adjustment, especially in cases where impedance changes are too small to detect accurately on the reader/writer side.
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 enhances the performance of short-range wireless communication by ensuring appropriate power supply to NFC cards, thereby improving communication reliability and efficiency across various card types.
Implementation Method 1
a reception circuit that receives a signal transmitted by load-modulating in a communication device, which is a partner in short-range wireless communication, via an antenna
Implementation Method 2
the reception circuit measures a modulation degree of the signal
Data Source
AI summary
The present disclosure relates to a communication apparatus, a communication method, and a program that enable improvement in performance of short-range wireless communication.The communication apparatus includes: a reception circuit that receives a signal transmitted by load-modulating in a card, which is a partner in short-range wireless communication, via an antenna; and a transmission power control unit that controls transmission power transmitted to the card on the basis of a reception signal modulation degree which is a modulation degree of the signal received by the reception circuit. Then, the transmission power control unit performs control so as to reduce the transmission power in a case where the reception signal modulation degree is less than or equal to a certain threshold value. The present technology can be applied to, for example, a communication apparatus that performs short-range wireless communication.