How to find which app, service, etc is using mobile data every 3hrs on the dot - for months?

[Android Central Question]

12 - 3 - 6 - 9 am & pm something uses a significant amount of mobile data... how do I find out specifically what is doing this at these exact times? If the Note 8 provides this info, how do I get there, or what app can I download that provides this info in particular - free or paid app idc. In settings, it shows an overview of usage by app, which doesn't help in identifying the culprit of usage at these times. Can't seem to find hour specific usage details in settings, at&t can't figure it out, installed My Data Manager app and if they do provide this info I can't figure out how to view it... please help!

 

[Rukbat]

One easy way is to disable mobile data at 11:59, 2:59, 5:59 and 8:59, AM and PM, and see what's not happening. The first time you do it, some app may complain that it can't connect - and you'll know.