Serial Bus Drive Strength Adjustment for RF Interference Mitigation
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Solution Overview
Problem
Mobile communication devices face electromagnetic interference (EMI) from high-frequency signals transmitted over serial buses, particularly in 5G-NR devices, which affects RF signal quality and reliability due to limited effectiveness of conventional solutions like spread-spectrum clocking and differential signaling.
Innovation Solution
A wireless communication device with a controller that measures RF signal quality and adjusts the signal strength of the serial bus transmitter to mitigate EMI by reducing power levels when signal quality falls below a minimum threshold, using pre-calibrated power levels for C-PHY or D-PHY interfaces, and dynamically changing clock frequencies to avoid interference with RF frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-frequency signals are transmitted over serial buses to achieve higher data rates, then productivity is improved, but electromagnetic interference is generated that degrades RF signal quality
Solution Approach 1:
The patent implements dynamic adjustment of serial bus signal strength based on real-time RF signal quality measurements. The system continuously monitors RF quality metrics and adapts the serial bus transmitter power levels accordingly, transitioning from static to dynamic operation to resolve the contradiction between maintaining high data rates and reducing EMI.
Solution Approach 2:
The patent changes the signal strength parameter of the serial bus transmitter dynamically. By adjusting the voltage swing or current drive levels of the serial bus interface based on RF quality conditions, the system can reduce EMI when RF signals are present while maintaining high data rates when RF interference is minimal.
2Object-affected harmful factors
If signal strength of serial bus transmitter is reduced to mitigate EMI, then RF signal quality is improved, but serial bus communication reliability may deteriorate
Solution Approach 1:
The patent implements a feedback mechanism where the system monitors both RF signal quality and serial bus communication status. When signal strength is reduced to improve RF quality, the feedback loop detects any serial bus errors and triggers corrective actions such as increasing signal strength or implementing error correction, thereby maintaining serial bus reliability.
Solution Approach 2:
The system performs self-adjustment by automatically monitoring its own performance metrics (RF quality and serial bus error rates) and making autonomous decisions about signal strength adjustment. This self-service approach ensures both RF quality and serial bus reliability are maintained without external intervention.
3Object-generated harmful factors
If conventional solutions like spread-spectrum clocking and differential signaling are used to reduce EMI, then electromagnetic interference is suppressed, but device complexity increases
Solution Approach 1:
Instead of implementing complex spread-spectrum clocking or differential signaling hardware modifications, the patent achieves EMI reduction by dynamically changing the signal strength parameter of the existing serial bus interface. This parameter-based approach reduces EMI through software-controlled power adjustment rather than hardware complexity.
Solution Approach 2:
The patent replaces complex hardware-based EMI suppression mechanisms (such as spread-spectrum clocking circuits or differential signaling infrastructure) with a simpler software-controlled power adjustment mechanism. This substitution reduces device complexity while achieving the same EMI mitigation goal.
Data Source
AI summary
Systems, methods, and apparatus for controlling radio frequency (RF) interference at a mobile communication device are described. A data communication apparatus has a wireless transceiver configured to transmit and receive RF signals, a bus interface circuit coupled to a serial bus and configured for operation as a display serial interface (DSI), and a controller. The controller is configured to receive a measurement of a reference signal representative of RF signal quality at the mobile communication device, determine whether the measurement of the reference signal indicates that the RF signal quality is less than a minimum RF signal quality level, and reduce signal strength of a transmitter in the bus interface circuit when the RF signal quality falls below the minimum RF signal quality level.