Authorized wireless communication standard

​​​​GSM 2G gprs 2.5G EDGE 2.75G

3G

4g in    NBIOT:cat.M2   lte cat.1 lte cat4 Difference and contrast

Reference resources

https://blog.csdn.net/AmazIOT/article/details/105159757

 https://www.elecfans.com/iot/1209809.html

lte 4g lte-a difference

https://blog.csdn.net/u010783226/article/details/87725020