Radio Link Diversity Management for Fading Mitigation
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Solution Overview
Problem
Radio wave fading in buildings significantly degrades the robustness of communication systems used in anti-intrusion, home automation, and temperature management systems, particularly affecting the transmission range and reliability between sensors, centralized devices, and actuation devices.
Innovation Solution
Implementing a method and system that utilize spatial and frequency diversity by transmitting messages in two distinct frequency bands, with sensors and centralized devices switching to a secondary frequency band if acknowledgment is not received in the primary band, and using antennas separated by a predetermined distance to mitigate fading issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single frequency band is used for transmission, then the device complexity is reduced, but the reliability of transmission deteriorates due to fading
Solution Approach 1:
The patent changes the frequency parameter by using two distinct frequency bands (first and second frequency bands) for transmission. When fading occurs in the first frequency band, the system switches to the second frequency band, thereby maintaining transmission reliability without requiring complex multi-antenna configurations at each sensor node.
2Reliability
If multiple antennas are used at each sensor, then the spatial diversity is improved, but the size and cost of sensors increase
Solution Approach 1:
Instead of adding spatial diversity through multiple antennas at each sensor (spatial dimension), the patent introduces frequency diversity by transmitting on two distinct frequency bands (frequency dimension). This allows reliability improvement without increasing sensor physical size or complexity.
3Reliability
If the second frequency band is always used, then the robustness against fading is improved, but the energy consumption and interference increase
Solution Approach 1:
The system uses the second frequency band partially - only when fading is detected in the first frequency band. The sensor transmits initially on the first frequency band, and only switches to the second band if an acknowledgment is not received, thereby conserving energy while maintaining robustness when needed.
4Reliability
If acknowledgment verification is implemented, then the transmission quality is improved, but the transmission time increases
Solution Approach 1:
The system implements a feedback mechanism where the sensor waits for an acknowledgment from the centralized device after transmission. If no acknowledgment is received within a timeout period, the sensor retransmits on the second frequency band. This ensures transmission quality while minimizing time loss by only triggering retransmission when necessary.
Data Source
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AI summary
The invention relates to a method for managing the spatial and frequency diversity of radio links between sensors, a centralized device and an actuation device located in a building in which radio waves are subject to fading, the sensors, the centralized device and the actuation device emitting messages in a first and a second frequency band.The process includes the steps of: - transferring, by a sensor, a message in the first frequency band via an antenna of the sensor, - transferring the message in the second frequency band via the antenna of the sensor if an acknowledgment of the message is not received, - transferring, by the centralized device (E500), another message in the first frequency band via a first antenna of the centralized device, - transferring, by the centralized device (E504), the other message in the second frequency band via a second antenna of the centralized device if an acknowledgment of the message is not received.