Wireless communication technology commonly used in the Internet of things

Preface

Wireless communication technology of Internet of things can be divided into short-distance communication technology and low-power long-distance communication technology according to communication distance （LPWA）.

• Short range wireless communication technology ： bluetooth 、WiFi、ZigBee
• Low power long distance wireless communication technology ：SigFox、LoRa、NB-IoT

Short range wireless communication technology

bluetooth

“ bluetooth ” It is a high-capacity short-range wireless digital communication technology standard , Its goal is to achieve the highest data transmission rate 1Mbps、 The maximum transmission distance is 10 centimeter ~10 Data transmission of meters , By increasing the transmission distance of transmission power, it can achieve 100 rice .

advantage ： Fast speed 、 Low power , High safety factor .

shortcoming ： There are few network nodes , Not suitable for multi-point control .

WiFi

WiFi It's a way to allow electronic devices to connect to a WLAN （WLAN） Technology , Usually use 2.4G UHF or 5G SHF ISM RF band .

advantage ： Wide coverage , Fast data transfer rate .

shortcoming ： Transmission security is not good , Poor stability , Slightly higher power , Poor networking capability .

ZigBee

ZigBee Is based on IEEE802.15.4 Standard low power LAN Protocol . According to international standards ,ZigBee Technology is a short distance 、 Low power wireless communication technology . The name （ Also known as the purple bee agreement ） The eight character dance originated from bees , Because of the bees (bee) By flying and “ hum ”(zig) The ground shakes its wings “ dance ” To share with your partner the information about where the pollen is , That is to say, bees rely on this way to form a communication network in the group .

Its characteristics are A little distance 、 Low complexity 、 Self organizing 、 low power consumption 、 Low data rate . It is mainly suitable for automatic control and remote control , Can be embedded in a variety of devices .

Low power long distance wireless communication technology

SigFox

SigFox The network uses ultra narrow band UNB technology , The transmission power level is very low , And still maintain a stable data connection .SigFox The wireless link uses unauthorized ISM RF band . The frequency varies according to national regulations , Widely used in Europe 868MHz, In America it's 915MHz.

SigFox Network topology is a Extensible 、 High capacity network , With very low energy consumption , While keeping it simple and easy to deploy Star cell based infrastructure .

SigFox Network performance characteristics ： Every day every device 140 Bar message ; Every message 12 Bytes (96 position ); Wireless throughput reaches 100 position / second .

SigFox It is also a fast commercialization LPWAN Network technology , It uses ultra narrow band technology , Make network equipment consume 50 The power of micro watt is two-way one-way communication or 100 Microwatt . This Agreement SigFox The company owns , Its founder is a French entrepreneur Ludovic Le Moan, Mainly to create low attack consumption 、 Low cost wireless Internet of things private network . at present ,Sigfox Our network covers France 、 Spain 、 Dutch and British 10 Big cities .

LoRa

LoRa It's an open source based MAC Low power Wan standard based on layer protocol , be based on Sub-GHz The frequency band makes it easier to communicate over long distances with low power consumption , It can be powered by battery or other energy collection methods .

LoRa The main features of wireless technology ： The long distance ：1-20km; Number of nodes ： All level , Even a million ; Battery life ：3-10 year ; Data rate ：0.3-50kbps.

LoRa yes LPWA One of the communication technologies , Is the U.S. Semtech The company adopts and promotes an ultra long distance wireless transmission scheme based on spread spectrum technology . This scheme changes the previous compromise between transmission distance and power consumption , Provide users with a simple way to realize long-distance communication 、 Long battery life 、 Large capacity systems , Further expand the sensor network . at present ,LoRa Mainly in the world's free band .

at present LoRa The network has been piloted or deployed in many places in the world , Up to now, the latest published data , There has been a 17 Countries have publicly announced plans to build networks ,120 There are running in many urban areas LoRa The Internet , Such as the United States 、 The French 、 Germany 、 Australia 、 India and other countries , Netherlands 、 Switzerland 、 South Korea and others are deploying or planning to deploy nationwide LoRa The Internet .

NB-IoT

NB-IoT The narrowband Internet of things is based on the cellular Internet of things , Its construction and cellular network , It only costs about 180KHz The bandwidth of the . Can be deployed directly in GSM The Internet 、UMTS The Internet or LTE The Internet , To reduce deployment costs 、 Achieve a smooth upgrade .

NB-IoT Focus on low power consumption and widely cover the Internet of things market , It's an emerging technology that can be widely used all over the world . have Wide coverage 、 More connections 、 Low speed 、 The cost is low 、 Low power consumption 、 Architecture excellence Other characteristics .

At present, the three major domestic operators NB-IoT The network has been Open business , Maybe some cities have not been covered . Two years ago (2018) We can use it when we do competitions , As far as I can guess , The last large-scale Internet of things long-distance communication technology used in China should be NB-IoT, because NB-IoT The number of connections can reach millions , and LoRa、SigFox Compared with the highest safety , But at present, the disadvantage is that the cost is still a little high , The operator charges about 20 element / year , The cost of a module is about 20-80 yuan , But with the expansion of the scale of use , Cost reduction is also a matter of time , Therefore, I am still optimistic NB-IoT It will become a standard of Internet of things communication .

Wireless technology comparison