Wireless data transmission is a very common art in the Internet of Things. Wireless data transmission includes three levels: node collection layer, intermediate transmission layer, and terminal monitoring application layer. The middle transmission layer is responsible for wireless data transmission. Specifically, it receives data from the lower end and wirelessly uploads it to the upper management layer (such as a server). It is the most critical and important in the wireless data collection system. a link. At present, the application of Zongheng intelligent control wireless data transmission technology is becoming more and more extensive. According to different application requirements, different wireless data transmission methods and wireless data transmission equipment are selected.
wireless data transmission technology
Common wireless communication technologies mainly include GPRS/CDMA, 4G, LoRa, NB-IOT, digital radio, spread spectrum microwave, wireless bridge and satellite communication, shortwave communication technology, etc. It is mainly used in remote areas or areas where it is not suitable to lay lines, such as coal mines, seas, areas with pollution or harsh environments, etc.
Wireless data transmission classification
Digital radio communication:
Digital radio is the abbreviation of digital wireless data transmission radio. It is a wireless data transmission station that uses digital signal processing, digital modulation and demodulation, and has functions such as forward error correction and equalization soft decision. Most of the working frequencies of digital radio stations use the 220–240MHz or 400–470MHz frequency bands. They are compatible with digital and telephone calls, have good real-time data transmission, dedicated data transmission channels, one-time investment, no operating fees, are suitable for harsh environments, and are stable. Good to wait for the advantages. The effective coverage radius of a digital radio station is about tens of kilometers, which can cover a city or a certain area. Digital radio stations usually provide standard RS-232 data interfaces, which can be directly connected to computers, data collectors, RTUs, PLCs, data terminals, GPS receivers, digital cameras, etc. It has been widely used in various industries, including aerospace, railway, electric power, petroleum, meteorology, earthquake and other industries. It has also made great progress and development in SCADA fields such as remote control, telemetry, shake signal and remote sensing.
GPRS/CDMA wireless communication technology:
GPRS (General Radio Packet Service) is a wireless packet switching technology based on the GSM communication system developed and operated by China Mobile. It is a technology between the second generation and the third generation. It is usually called 2.5G. It utilizes ” Packet exchange? Concept development of a wireless transmission method. Packet switching encapsulates data into many independent packages, and then transmits these packages one by one. The form is somewhat similar to sending a package. Its advantage is that it only takes up bandwidth when there is data that needs to be transmitted, and it is priced based on the amount of data, which is effective. to improve network utilization. The GPRS network supports both circuit-type data and packet-switched data, so that the GPRS network can be easily connected to the Internet. Compared with the circuit-switched data transmission method of the original GSM network, the GRRS packet-switching technology has real-time online “pay-as-you-go billing” High-speed transmission and other advantages.
CDMA (the English abbreviation of code division multiple access) is a new wireless communication system based on code division technology and multiple access technology run by China Telecom. Its principle is based on spread spectrum technology.
Short wave communication:
According to the classification of the International Radio Advisory Committee, shortwave refers to electromagnetic waves with a wavelength of 100m-10m and a frequency of 3MHZ-30MHZ. Shortwave communication refers to radio communication using short waves, also known as high frequency (HF) communication. Shortwave communication can be divided into ground wave propagation and sky wave propagation. The attenuation of ground wave propagation increases with the increase of operating frequency. Under the same ground conditions, the higher the frequency, the greater the attenuation. The use of ground waves is only suitable for short-range communication, and its operating frequency is generally selected below 5MHZ. Ground wave propagation is less affected by weather and is relatively stable. The channel parameters basically do not change with time, so the channel can be regarded as a constant parameter channel. Sky wave propagation is a method of long-distance communication in which radio waves are reflected by the ionosphere. After obliquely projected electromagnetic waves are reflected by the ionosphere, they can be transmitted to the ground thousands of kilometers away. The propagation loss of sky waves is much smaller than that of ground waves. After multiple reflections between the ground and the ionosphere, they can reach extremely distant places. Therefore, sky waves can be used for global communications. Sky wave propagation is extremely unstable due to severe effects of ionospheric changes and multipath propagation, and its channel parameters change rapidly with time, so it is called a variable parameter channel. The characteristics of shortwave communication are: low construction and maintenance costs, short cycle, simple equipment, easy circuit scheduling, strong invulnerability, narrow frequency band, small communication capacity, and poor sky-wave channel signal transmission stability.
Wireless bridge:
Wireless bridge is the product of the combination of wireless radio frequency technology and traditional wired bridge technology. Wireless bridges are designed for point-to-point interconnection between networks using wireless (microwave) for long-distance data transmission. It is a storage and forwarding device that realizes LAN interconnection at the link layer. It can be used for long-distance (up to 50Km) and high-speed (up to 100 Mbps) wireless networking between fixed digital devices and other fixed digital devices. Both spread spectrum microwave and wireless bridge technologies can be used to transmit large data volume signal transmission services such as video surveillance that require high bandwidth.
Wireless data transmission applications
◆ Wireless monitoring of oil drilling tension
◆ Short distance/long distance wireless data transmission
◆ Wireless monitoring of security equipment
◆ Wireless bai485, wireless PLC
◆ Urban pipe network pressure and temperature monitoring
◆ Power line wireless alarm
◆Industrial remote control, zhuan telemetry
◆Industrial automation
◆Oilfield data collection
◆UAV system communication control
◆Railway wireless communication
◆Coal mine safety monitoring system
◆Tap water pipe network monitoring
◆Broadband access and sharing
◆Wireless LAN
◆Network control of parking lot equipment
◆Other RS-232/RS-485 device networking applications
◆Hydrological monitoring system
◆Sewage treatment monitoring
◆PLC control and management
The above is the relevant introduction to ” Wireless Data Transmission Applications “, I hope it will be helpful to you! This article is provided by Chengdu Zongheng Intelligent Control – a professional Internet of Things data transmission expert.
Keywords: wireless data transmission