TubeNet

I have never noticed a pattern like that.

If I were to make an uneducated guess, it would be that you are seeing the result of an added strain on your cellular network due to everybody streaming and downloading to their new phones. Everybody's gotta get all their apps downloaded, and try out all the features, etc. (In my experience, when my phone struggles to connect to the network, the battery drains faster and of course, there are more dropped calls.)

Frankly, I think a lot of the non-smart phones from the last several years have *much* better call quality than the fancy new phones.

When I got my latest (smart) phone, I showed it to my wife and joked "it makes phone calls, too!"