Nb-iot technical summary

Recently summarize the projects done before , Think about it all 2 It was years ago , Memo ：

Due to the impact of the Internet of things on power consumption 、 Cover 、 The number of connections , Very, very sensitive . And for speed , Most Internet of things applications are not sensitive .（ Take a meter reading , Report the latitude and longitude of each position , Can have a few bytes ？ How much bandwidth is needed ？）, So the traditional WLAN The Internet of things （WLAN The Internet of things , With Wi-Fi、 bluetooth 、Zigbee、Z-wave And so on .） Cannot meet these needs , So it was born LAWAN The concept of

LPWAN The concept of ：

LPWAN,Low Power Wide Area Network, Low power wan . The name has its two most important features ： low power consumption 、 Wide coverage .LPWAN The emphasis is on coverage , At the expense of speed . It also includes many technical standards . At present, the mainstream ones are ：NB-IoT、LoRa、Sigfox、eMTC.
NB-IoT, It's one of them . The full name is Narrow Band IoT, That is, the narrowband Internet of things （ Band width , Slow speed ）.

Power consumption ,NB-IoT At the expense of speed , But in exchange for lower power consumption . Adopt a simplified protocol , More suitable design , Greatly improve the standby time of the terminal , part NB terminal , The standby time is claimed to reach 10 year ！

Signal coverage ,NB-IoT Better coverage （20dB gain ）, Even if your water meter is buried under the well cover , Nor does it affect signal transmission and reception .

Number of connections , Each cell can support 5 Million locations , Pretty tough . Even if the neighborhood is crowded 5 Ten thousand pigs , It can also easily monitor each head .

The most important , Cost price . You go bull again. , If the cost is high , The price is too expensive to afford , It's also for nothing .NB-IoT The cost of communication module is very low , Each module is hopefully pressed to 5 Even less in dollars , It is conducive to mass purchase and use .( Actually 5 Knives are already quite expensive )

At home NB-IOT Frequency band ：

NB-IoT Than LTE and GPRS The base station has been upgraded 20dB The gain of , Expect to cover the underground garage 、 The basement 、 Underground pipelines and other places where signals are hard to reach . According to the simulation test data , In stand-alone deployment mode ,NB-IoT The coverage capacity can reach 164dB, In band deployment and protection band deployment have yet to be simulated and tested .
　　 Usable owned by domestic operators NB-IoT Frequency band
　　 Finished module test ：SIM7020 SIM7000 modular
　　 Include TX RX power; Communication bandwidth ; Sleep power consumption ; Power on time ;TCP/UDP Number of connections ; Networking delay (PSM);
　　MQTT Connection, etc ;
　　 The specific results will not be posted for the time being