s/work/patent blackmail/g

I would buy that a decent modem is harder than many CPU designs, maybe even most. But harder than state-of-the-art? Surely not, have you seen the complexity?

And even CPUs (esp state of art) have to worry about radio effects, as in avoiding internally and across chipset.

State of the art CPUs aren't fundamentally different to more basic CPUs. They just have fancier microarchitectures, better branch predictors, more cache, etc.

Easy to believe radios would be an order of magnitude harder, what with the ancient proprietary standards and actual physical radio stuff. (The closest CPUs get is serdes and in my experience those are bought in from Synopsys et al.)

I never worked on radio modems, but I've worked on wireline modems: the issue is not the math or the standard algorithms, it's making it interoperable with everything that's existing out there and all environment conditions while working around bugs of other implementations.

It is a ridiculous amount of work and if you're new to the business, it takes a long time just to be build the lab test suite. And you need to support not just the latest and greatest protocols but also legacy ones. The operators have their own say and test labs as well and they all have slightly different setups and requirements.

> And even CPUs (esp state of art) have to worry about radio effects, as in avoiding internally and across chipset.

Radio effect are rarely an issue with regular chips. Crosstalk within a chip only happens between wires that are within hundreds of nanometers separated from each other.

> Radio effect are rarely an issue with regular chips.

I'm an amateur, so welcome correction with this, but I'm also not convinced. For one example, ref this RFI mitigation with Intel's gen 12 processors: https://edc.intel.com/content/www/cn/zh/design/ipla/software...

I meant RF impact on the internal functioning of the chip, not the other way around. EMI has always been a thing, it's not specific to state of the art CPUs.

The hard part is not the modem design per se.

The hard part is designing a good modem while also unambiguously working around all the Qualcomm patents in all the jurisdictions that have iPhone, which is all of them.

Because if you don’t do that, you’re still paying Qualcomm which defeats an important purpose of making your own modem.

All those patents are standards-essential, which means Qualcomm (and anyone else involved in the standardization process for cellular networks) has to license them under "FRAND[0]" terms, which at least for this scenario means "for the same price we'd license them to Samsung or Intel[1]". It also means that design-arounds are not possible; if you design a different technology from the one Qualcomm owns, you're not speaking 5G anymore. That's why we have these legal rules on standards-essential patents.

[0] Fair, reasonable, and non-discriminatory. Each one of those words has a funny legal definition separate from whatever English you're thinking of.

[1] Who, incidentally, sold Apple the modem division that made the C1, because Intel is nothing but a bottomless pit of bad management decisions

I’ll admit with not being up to speed here, my information is actually fairly old, but Qualcomm is famous for skirting its FRAND obligations and as far as I know “no license, no chips” is still de rigor. https://www.sunsteinlaw.com/publications/no-license-no-chips...

Apple is most probably paying Qualcomm for these technologies. They think however that it is commercially beneficial to have their own implementation.

In 2025 it is time to give credit for Apple's PR spreading whole misinformation online during and after the trial. Macrumours and 9to5mac loves to repeat those narrative about Apple no longer has to pay any patent fees when they make their own modem.

As the reply below, Apple still has to pay its SEP. Given Apple has its current deal with Qualcomm until 2027 with time to extend further we likely won't know the full details. Previously it was 5% of Wholesale price for all Qualcomm patents whether they are SEP, wireless or not. With a cap or maximum $20 per smartphone meaning the Pro range don't have to pay a lot more. And rebate towards the modem Apple purchase. The reality after deducting rebate Apple was paying closer to 5%. For reference Ericsson ask for 3% on 5G SEP, previous Cory ruling suggest reality was closer to 2%.