Smart home is a deepening manifestation of wireless radio frequency technology

Modern families have shifted from pursuing luxurious home decoration to home intelligence, enjoying the diversified information brought by intelligence, as well as a safe, comfortable and convenient living environment. Especially with the development of the Internet of Things and 3G mobile technology, intelligent life allows you to truly experience that home is always by your side.

Smart home system is an efficient, comfortable, safe, convenient and environmentally friendly home living environment that uses computers, embedded systems and communication network technologies, takes home as a platform, and integrates automation, informationization and intelligence. At present, the degree of intelligence of smart home life depends on the efficiency and reliability of information transmission, which mainly includes wired transmission and wireless transmission. Wired transmission has the disadvantages of complex wiring, poor scalability, inconsistent standards and difficult construction, and it is difficult to gain a large market space. Wireless radio frequency technology is a short-range, low-complexity, low-data-rate and low-cost wireless communication technology. Because it does not require rewiring, it uses point-to-point radio frequency technology to control home appliances, lights and other equipment, and is relatively easy to install and has a simple control method. It has been widely used in smart homes in recent years. Therefore, the realization of intelligent life based on wireless radio frequency technology for information transmission is the focus of current smart home research, which will provide people with an efficient, comfortable, safe and convenient living environment.

1. System Architecture

The smart home system built based on wireless radio frequency technology mainly includes a home gateway and several communication sub-nodes. The home gateway and each wireless communication sub-node are equipped with wireless transceiver modules, and data and control information are transmitted between the gateway and each sub-node to achieve information flow sharing between them. Wireless communication sub-nodes mainly include smart remote controllers, smart sub-controllers, smart switches, etc.

The home smart gateway is the core of the system. It uses a 32-bit reduced instruction set computer ARM processor to build an embedded Linux operating system platform. The status is set and queried through the keyboard or touch screen LCD display. The smart gateway is connected to the Internet and PSTN, and can convert the received control commands (including local remote control commands, remote telephone voice commands, remote mobile phone commands, remote computer commands, etc.) into wireless radio frequency signals, and transmit them through the radio frequency transmission module to realize intelligent home control.

On the one hand, the smart remote controller communicates with the home gateway through a wireless interface, and on the other hand, it has an infrared self-learning function, which can decode, learn, and store the infrared code values ​​sent by different infrared remote controllers, realizing the integration of multiple infrared remote controllers. The buttons on the LCD screen of the smart gateway and the keyboard of the smart remote controller correspond one to one in position. The user defines different key instructions on the buttons of the smart remote controller and binds infrared codes with different control functions. The smart remote controller sends the learned infrared signal code value to the infrared intelligent control center or infrared sub-control center through the wireless transmission module to realize the registration of the infrared code value on the smart sub-controller. When entering the smart home control interface on the smart gateway and pressing the control button of an electrical device, the code value is transmitted through the wireless transmission module as a radio frequency signal; the smart sub-controller compares the received wireless code value in the established list, converts it into an infrared signal and transmits it to realize the control of home appliances. The smart switch can receive the code value of the wireless signal transmitted by the smart gateway or smart remote controller to realize the switch action of the home appliance.

2. Features and advantages

With the continuous improvement of digital communities, the maturity of 3G technology and the continuous development of the security market, digital smart home systems have gradually become the mainstream of building intercom systems. Xiamen Lilin Technology has worked hard and cooperated with many well-known universities to systematically integrate cutting-edge technologies such as the Internet, multimedia, radio frequency carriers, security, monitoring, detection sensing, and biometrics. It uses universal and complete communication protocols to ensure the transmission capacity and reliability of the system and build a smart home platform that integrates multiple systems. In particular, the smart home system is built based on wireless radio frequency technology, and with the help of 3G technology and Internet technology, remote control functions are realized, which greatly improves people's lives.

(1) Optimize H.264 encoding and decoding algorithm

The key to digital smart home systems based on wireless radio frequency technology is how to achieve remote control functions with the help of 3G technology and Internet technology, especially how to improve the quality of remote video transmission. To address this issue, we focus on studying the H.264 codec algorithm, improve the motion estimation module that consumes the most time in the H.264 encoding process, reduce the computational complexity of the H.264 codec, effectively improve the H.264 codec efficiency, and ensure better video transmission effects under low bandwidth conditions.

(2) Two networks in one

Building intercom systems generally use a dedicated network for exclusive use, that is, a community LAN is built, and each household communicates with each other through the LAN. The use of a dedicated network improves the stability and reliability of the system, but at the same time increases the cost. Lilin Technology's digital smart home system integrates the Internet and the digital building intercom system network into one, saving the various costs brought about by rebuilding the community LAN. The system has made improvements in data compression and confidentiality of network transmission to minimize the impact of the digital building intercom system network on the original Internet, realizing the integration of the two networks and sharing of the two networks. During actual installation and use, residents only need to connect the digital terminal device to a port on their own switch, and connect the other ports to the home PC to realize the digital building intercom within the community, while ensuring the Internet access of the home PC.

(3) System integration and self-contained system

Smart home can be integrated with security alarm, video intercom and remote control into a comprehensive platform to realize information sharing and linkage control. At the same time, smart home can be a self-contained platform and can be operated and controlled independently when out of the system. This design method can meet the requirements of realizing smart home operation platform in ordinary residences. In particular, the communication between various home control devices based on wireless radio frequency technology can be convenient for old houses without pre-laid wiring.

(4) Mainnet and subnet information sharing

The home gateway is a device in the home control subnet. The sub-gateway can interconnect with the devices in the home control subnet and provide interfaces with the home main network for various devices in the home control subnet, so that each subnet device can obtain various services and realize the configuration and management of the home control subnet. When disconnected from the home main network, each terminal device in the home control subnet can work normally. Each terminal device can share information and control functions with each other through the home control subnet. Through this mechanism, any control panel can control the entire home.

(5) Bus conflict avoidance and single-fire power supply

When the home main network and the home control subnet control the terminal device at the same time, the bus conflict mechanism is used to avoid it through priority. Especially in wireless transmission, the field bus conflict avoidance mechanism is flexibly borrowed to effectively solve the problem of avoiding wireless signals transmitted by multiple devices at the same time. Data transmission adopts two-way control to improve the reliability and stability of the system. Especially when data transmission occurs, the bus conflict mechanism can be used more flexibly to avoid it. In order to take into account the convenience of old houses without pre-laid lines, the system adopts a single-fire power supply method to facilitate customer installation and retain the original wiring structure. Considering the problem of low power consumption of single-fire power supply, the system enters sleep mode under normal conditions and waits for external interrupt triggering. The wireless receiving module adopts an intermittent working mechanism, and the microprocessor makes intermittent judgments to minimize the system power consumption and achieve energy saving and environmental protection.

(6) Flexible networking: combination of wired and wireless

Taking into account the problems of signal attenuation during wireless RF signal transmission, the system adopts a combination of wired and wireless networking. Wireless RF signals are used for data transmission on the same floor, and wired data transmission is used between floors, so as to realize comprehensive and efficient sharing of system information.