On: iPhone 12 withdrawn from French market for non-com...

[londons_explore]

This can be fixed in software. They'll have to deploy a baseband update that reduces the maximum transmit power.

The user-visible effect will probably be a reduction in upload speeds (by about 30% in most cases).

[pjc50 → londons_explore]

Upload speed is not a linear function of TX power?

[londons_explore → pjc50]

Very roughly, yes it is. 1-(4/5.74) = 30.3%

It is possible however that this SAR violation only applies to certain bands or that the cell tower already is requesting a lower transmit power. Therefore there is a good chance users don't see much impact.

[pjc50 → londons_explore]

?? where are you getting that equation from ??

Linked to SNR, maybe, but that's not the same thing as max TX power unless you're standing right at the edge of the cell.

[jesprenj → pjc50]

Not parent, just asking the same question.

https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theore...

There's a log here, so it doesn't even seem linear to SNR.

Would SNR increase linearly to TX power?

I don't know.

[yuppiepuppie → londons_explore]

As someone who bought a 1k+$ phone from Apple i would be pissed if they dropped upload speed by that much. Surely there has to be an SLA that they have to uphold. No?

[pjc50 → yuppiepuppie]

They can't guarantee anything at all, and data link speeds are at best the responsibility of your carrier.

[londons_explore → yuppiepuppie]

In a way, you have had an unfairly high upload speed for the last 3 years, while every other phone manufacturer has been sticking to the rules and therefore sees lower speeds.

[layer8 → yuppiepuppie]

> Surely there has to be an SLA that they have to uphold.

What makes you think that?