NFC Frame Rate Negotiation for Stable PCD-PICC Links
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Solution Overview
Problem
The ISO/IEC 14443 protocol-based near-field communication (NFC) systems face issues with link disconnections due to changes in air interface quality, leading to a loss of link exception recovery and frame rate negotiation control capabilities.
Innovation Solution
A method where a PCD sends an activation frame indicating independent transmission rates for application and target frames, allowing the PCD to maintain communication by switching to a lower rate for target frames, and a PICC responds with acknowledgment and rate negotiation frames to stabilize the link.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single transmission rate is negotiated between PCD and PICC, then data transmission efficiency is improved, but link stability deteriorates when air interface quality changes
Solution Approach 1:
The patent segments the transmission rate control into two independent parts: a first transmission rate for information frames (I-frames) and a second transmission rate for control frames (R-frames and S-frames). This segmentation allows each frame type to use optimized transmission rates independently, resolving the contradiction between efficiency and stability.
Solution Approach 2:
The patent introduces dynamic rate adjustment where the second transmission rate for control frames can be independently adjusted based on link quality conditions. When air interface quality deteriorates, the system can lower the second rate to maintain control frame transmission, while the first rate continues at higher speeds for data efficiency.
2Speed
If high transmission rate is used for information frames, then data transmission speed is improved, but link disconnection occurs when air interface quality deteriorates
Solution Approach 1:
The patent uses control frames (R-frames and S-frames) transmitted at a separate second rate as intermediaries to maintain link connectivity. These control frames act as a protective layer that ensures link continuity even when information frames at high speed fail due to poor air interface quality.
Solution Approach 2:
The patent changes the transmission parameter structure by introducing two independent rates instead of one. The first rate for information frames can be optimized for speed, while the second rate for control frames is optimized for reliability, allowing parameter optimization for different functional requirements.
3Reliability
If transmission rate is reduced to maintain link stability, then link disconnection is prevented, but data transmission efficiency decreases
Solution Approach 1:
By segmenting the transmission system into two independent rate-controlled channels, the patent allows the information frame channel to operate at high efficiency while the control frame channel operates at lower stability-oriented rates, eliminating the need to reduce overall efficiency for stability.
Data Source
AI summary
In a transmission rate determining method, a proximity coupling device (PCD) sends an activation frame to a proximity integrated circuit card (PICC). The activation frame indicates at least a first transmission rate used to transmit a first information frame and a second transmission rate used to transmit a target frame. The first information frame is used to transmit application information. The target frame includes at least one of a second information frame or a third information frame, the second information frame is used to transmit receive ready information, and the third information frame is used to transmit control information. The PCD receives an acknowledgment frame from the PICC. The acknowledgment frame indicates that the PICC has received the activation frame. Then, the PCD transmits the first information frame with the PICC at the first transmission rate, and transmits the target frame with the PICC at the second transmission rate.