> Will LTE continue to work when 6G rolls out in 3 years?

A significant change that came with LTE is the use of OFDM as the base of the air interface, which means that cellular providers no longer need to allocate large segments of spectrum to one protocol or another. Towers that were upgraded from 4G to 5G didn't need to disable 4G or consistently split their spectrum between the two they way they did when upgrading from 2G to 3G or 3G to 4G, they can dynamically allocate subchannels in each mode based on the immediate needs of their users.

It seems unlikely that whatever technologies come in the future will regress in this way, so there shouldn't be a need for a hard cutoff at any point and I'd expect LTE devices to keep working for many generations to come.

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ChocolateGod a few seconds ago | parent | next [-]

[delayed]

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retatop 2 hours ago | parent | prev | next [-]

I don't think your conclusion is correct. 4G -> 5G will result in 5G networks completely consuming the 4G ones. T-Mobile has already been talking about shutting down LTE in a few years. The reason afaik that 4G and 5G are seemingly compatible right now is that most networks are in 5G NSA mode (non standalone) which means that LTE is actually used for negotiation and orchestration stuff, with 5G only used for the actual data pipe. I have been told that most of the benefit of 5G comes with 5G SA (standalone), but that requires not supporting the LTE stuff

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cowlevel an hour ago | parent [-]

Ironic given that LTE, literally called Long-Term Evolution, was supposed to make future backwards incompatible changes unnecessary.

	▲	DaiPlusPlus 26 minutes ago \| parent [-]
		> was supposed to make future backwards incompatible changes unnecessary I struggle to think of any system/scheme/protocol/spec/etc that promised this to have actually delivered. One can never predict the future.

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gruez 2 hours ago | parent | prev | next [-]

It's not just spectrum, though. The core network is totally different than 5G SA or whatever 6G has. Maintaining all of that will eventually be considered not worth the trouble, and it'll be decommissioned. If anything decommissioning will be faster for LTE because unlike 2G/3G (which were needed because VoLTE support was flakely and had device whitelists) there isn't much point in keeping LTE around for legacy reasons.

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cowlevel an hour ago | parent [-]

What are the differences between 4G and 5G core networks?

	▲	gruez an hour ago \| parent [-]
		https://en.wikipedia.org/wiki/5G#Core_network_architecture Big enough that most carriers can't even launch 5G with its associated core network ("5G standalone"), and had to use the kludge of 5G + 4G core network ("5G non-standalone)

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OJFord an hour ago | parent | prev [-]

> they can dynamically allocate subchannels in each mode based on the immediate needs of their users.

Right, so if I'm still rocking 4G only while 'everyone' else in the area is using 6G with some other stragglers on 5G, ...

	▲	cowlevel an hour ago \| parent [-]
		They're (mostly) the same channels shared by all of them. It's not like an ethernet address (where everyone on the network speaks the same protocol and just ignores packets not for it), it's a radio frequency timeslice that's allocated to you, and you and your nearby tower can speak any radio modulation they want in that timeslice, even ones that other phones or other towers don't support. However new technologies sometimes also bring new spectrum blocks like mmwave 5G.