Sub-GHz Air Conditioner Networking Through Walls and Floors
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Solution Overview
Problem
Conventional air conditioner wireless communication systems face challenges in achieving long-distance communication through multiple floors and walls due to high-frequency band limitations, complexity, and high power consumption, making it difficult to implement a low-cost, low-complexity, and low-power communication system.
Innovation Solution
The air conditioner system employs a Sub-GHz band frequency for wireless communication between indoor and outdoor units, using an optical orthogonal code for initial encryption and a chaotic signal for secondary encryption, enabling secure and asynchronous reception, and featuring a non-coherent reception method to simplify the hardware configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional commercial wireless communication (Wi-Fi, ZigBee, Z-wave) using 2.4 GHz or 5 GHz high-frequency band is used, then wireless communication can be established, but long-distance wireless communication through floors or walls in a building becomes difficult
Solution Approach 1:
The patent changes the frequency parameter from conventional 2.4 GHz or 5 GHz bands to Sub-GHz band (e.g., 900 MHz). This parameter change enables the wireless signal to penetrate walls and floors more effectively, achieving long-distance communication through building structures while maintaining communication reliability
2Reliability
If CDMA method with coherent receiver and rake reception function is used, then multi-user division and secret communication can be accomplished, but hardware configuration becomes complicated
Solution Approach 1:
The patent extracts and eliminates the complex coherent receiver and rake reception function hardware from the CDMA system. Instead, it uses a non-coherent receiver with optical orthogonal codes that achieve secret communication and multi-user division without requiring the complicated synchronization hardware, thus simplifying the overall system configuration
Solution Approach 2:
The patent replaces the mechanical/coherent synchronization system with an optical-based non-coherent reception system. By using optical orthogonal codes and envelope detection, the system achieves the same security and multi-user capabilities without the complex mechanical synchronization hardware
3Productivity
If conventional wireless communication system is implemented, then data transmission can be achieved, but it becomes difficult to implement a low-cost, low-complexity, low-power system
Solution Approach 1:
The patent adopts inexpensive Sub-GHz transceivers and simple optical orthogonal code implementation that can be easily manufactured and deployed. The system uses cost-effective envelope detectors and non-coherent reception circuits instead of expensive coherent receivers, achieving low-cost implementation while maintaining data transmission capability
Solution Approach 2:
The patent changes multiple parameters simultaneously: frequency band (to Sub-GHz for better penetration), modulation approach (to non-coherent envelope detection for lower complexity), and coding scheme (to optical orthogonal codes for security). These parameter changes collectively enable a low-cost, low-complexity system that maintains productivity
Data Source
AI summary
An air conditioner is provided that includes a plurality of indoor units configured to be distributed and installed in a plurality of floors in a building; a controller configured to monitor and control the plurality of indoor units; and a wireless communication unit configured to transmit and receive data by the controller, the plurality of indoor units, and one outdoor unit using a wireless communication method. The wireless communication unit comprises a transmitter and a receiver using a Sub-GHz band frequency. The transmitter includes an optical orthogonal code generator configured to first cipher source data using an optical orthogonal code, and a narrow-band chaotic signal generator configured to secondarily cipher using a chaotic signal. The source data is sequentially encrypted through the optical orthogonal code generator and the narrowband chaotic signal generator and then transmitted.