Infrared Remote Controller Pulse String Transmission for Anti-Interference

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Solution Overview

Problem

Infrared remote control systems using the NEC protocol have a weak anti-interference capability and low success rate due to susceptibility to environmental interference, allowing only one complete signal transmission per key press interval.

Innovation Solution

The method involves encoding binary sequences into pulse string signals with distinct pulse widths for each binary segment and transmitting at least two identical pulse string signals in an infrared signal form before the key is released, using a preset transmission cycle to improve signal reception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If only one complete infrared signal is transmitted per key press interval according to NEC protocol, then the signal transmission format is simple and standardized, but the anti-interference capability is weak and the success rate of remote control is low

Engineering Contradiction:
Improveanti-interference capabilityVSAvoidsignal transmission complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies periodic action by transmitting the infrared signal multiple times within a single key press interval. Instead of sending only one complete signal as in the NEC protocol, the system sends several identical signals in succession (e.g., 3-5 times) with each signal separated by a short interval. This periodic repetition ensures that at least one complete signal is likely to be received successfully even when environmental interference blocks some transmissions, thereby significantly improving anti-interference capability and remote control success rate.

Inventive Principle:
Principle #19Periodic action

2Reliability

If multiple pulse string signals are transmitted rapidly before key release, then the success rate of signal reception is improved, but the time required for transmission increases

Engineering Contradiction:
Improvesuccess rate of remote controlVSAvoidtransmission time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies partial or excessive action by transmitting more signals than the minimum single signal required for basic operation. Specifically, it sends multiple identical signals (excessive action) within the key press interval, ensuring that even if some are lost to interference, enough complete signals reach the receiver. The system optimizes the number of repetitions to achieve reliable communication without excessively prolonging the transmission time, balancing reliability and time efficiency.

Inventive Principle:
Principle #16Partial or excessive action

3Adaptability or versatility

If the infrared signal transmission follows the NEC protocol with fixed pulse widths, then the protocol compatibility is maintained, but the adaptability to different interference environments is reduced

Engineering Contradiction:
Improveenvironmental adaptabilityVSAvoidprotocol complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-defining multiple sets of pulse width parameters that can be selected based on different interference environments. Before actual signal transmission, the system can preliminarily determine the appropriate pulse width configuration (e.g., different high-level and low-level pulse widths) suitable for the current environmental conditions. This allows the system to adapt to various interference scenarios while maintaining protocol compatibility, as the basic NEC protocol structure is preserved but with flexible parameter selection.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2924669B1Method and apparatus for transmitting infrared signal and remote controller
Publication Date: 2018.08.29 XIAOMI INC
  • EP2924669B1 patent drawingFigure 1~2
  • EP2924669B1 patent drawingFigure 3A~3B
  • EP2924669B1 patent drawingFigure 3C~4

AI summary

The present disclosure relates to a method and an apparatus for transmitting an infrared signal, and a remote controller, and belongs to the technical field of wireless transmission. The method includes: for each key in a remote controller, generating (202) a binary sequence corresponding to the key when the key is pressed; encoding and modulating (204) the binary sequence to obtain a pulse string signal; and transmitting (206) at least two pulse string signals in an infrared signal form before the key is released.