[crote]

Ironically 3G is often the reason 4G/5G has poor reception.

1G/2G/3G all need to have a dedicated channel for itself. They were usually given the frequencies with the longest range, which is the 800MHz band. When 4G was introduced it couldn't share that band with 3G, so it was usually given space on higher frequencies around 1800MHz and 2500MHz. Those bands also allow a higher data rate, and anyone out of their range could fall back to 3G so it's a win-win, right?

Buuuuut now we're stuck with 4G in a band with poor reception, and throwing out 3G means losing coverage. Ideally the 4G sites in low-density areas would be moved to 800MHz, but that's going to require significant effort because every single antenna will need to be modified by engineers. Had 4G been deployed to 800MHz initially this wouldn't have been an issue - but that wasn't really possible because it would've meant worse speeds for existing 3G customers.

This whole issue is avoided with 5G because 4G and 5G were explicitly designed to coexist on the same channel.

[cogman10]

All this is true, but there is a bit of nuance. Long range isn't always desirable for wireless communication. Certainly if you are talking about low population areas then it's king. But when you start talking about heavily populated areas the long range becomes a detriment for the network stability. You can end up with cell towers servicing too many people (streaming youtube) which can ultimately overload a node but also cause a lot of signal disruption.

As population density goes up, the higher frequency bandwidths become much more desirable. This is part of the reason why the WiFi standard has been pushing up into 5ghz and 60ghz frequencies. Because you don't want your wifi signal to be yelled over to the neighbor.