6 ms·

What’s the fundamental reason why SOTA modems are more challenging than microprocessors for Apple? Intuitively I would’ve guessed the opposite was true.

by zdyn5 3y ago

lbourdages 3y ago
I would guess lack of expertise? Apple purchased PA Semi a while ago and the team went on to work on their processors. Have they purchased a company specialized in mixed-signal circuit design? That's one of the key differences, a modem contains a lot of analog circuitry and analog is very different from digital.
- donavanm 3y ago
  PA Semi was 2008 or so, and Intrinsity in 2009-10. In both cases they came with (more or less) working products, an existing relationship, and coherent engineering teams with an active development pipeline. Its fair to say the intel modem folks have a lot of that individually, but Im not clear how much of the whole transferred over. Edit: and the HwEng org already had established VLSI, SoC, and PCB groups shipping products before those acquisitions happened.
- kalleboo 3y ago
  > Have they purchased a company specialized in mixed-signal circuit design? They bought Intel's modem business, which was originally part of Infineon. Intel had working 4G modems which were only a year or two behind Qualcomm to the point where most users wouldn't notice. But they never seemed to manage to make the jump to 5G.
  - ikekkdcjkfke 3y ago
    5G is overrated
    - kalleboo 3y ago
      It may be, but all new network capacity is being built on 5G so a phone without it will suffer more and more in performance, especially in crowded areas/events.
    - xwolfi 3y ago
      5G is absolutely insane. 100Mb/s for 20 USD/mo on a mobile phone in Hong Kong is absolutely mind-blowing. I suppose in low density areas like Tokyo, New York or Paris, it might be slower in some patches ?
      - kalleboo 3y ago
        I typically get around 300-600 Mbps on 5G, but in some areas I've seen speeds up to 1.3 Gbps (on NR, not even mmWave). This is in a Japanese city of pop 300,000
      - drevil-v2 3y ago
        What are you doing on a handheld device screen that would blow your mind once the novelty of seeing the big numbers on speedtest app wore off? Genuinely curious- what can you do on 5G phone that you can’t on your 4G phone?
        Sporktacular 3y ago
        Run a faster hotspot.
        elcritch 3y ago
        Upload video, sync photos, backup the phone, watch 4k movies, etc
        PeterisP 3y ago
        A reasonably frequent usage of this speed is for families to switch over to mobile internet as the primary service for your home, having multiple people watch "TV" and videoconference all while someone is gaming (or dowloading a 40 Gb game) all through a single 5G modem.
        astrange 3y ago
        Among other things, 5G works better in crowds. And the faster your transfer finishes, the faster you can turn the antenna off and save power.
      - qwertimus 3y ago
wyldfire 3y ago
IMO cellular network protocols are remarkably challenging to understand. Then you add to that various quirks of certain network operators, optimal power consumption and throughput, security. They probably want their design to work as well as the baseline one, and globally.
- staticautomatic 3y ago
  As someone who used to work occasionally on explaining 3GPP/2 to laypeople, I’d call “remarkably challenging” an understatement.
tech-historian 3y ago
From the article: "Modem chips are trickier to make than processing chips because they must work seamlessly with 5G wireless networks, as well as the 2G, 3G and 4G networks used in countries around the world, each with its own technological quirks. Apple microprocessors run software programs designed solely for its iPhones and laptops." Also: "[Apple's modem] chips were essentially three years behind Qualcomm’s best modem chip. Using them threatened to make iPhone wireless speeds slower than its competitors."
- justusw 3y ago
  I wonder what some of the regional quirks are, instances where the implementation strays from the standard, but if you don’t do it in quirks mode, you can’t connect to the cellular connection or calls will not go through etc. A sort of woops, non-strict YAML moment, but in telecommunications.
testrun 3y ago
The Apple CPU's architecture is already known (ARM). To iterate from there is probably easier than designing a modem without the basics already designed and ready to go.
- secabeen 3y ago
  Apple also has a pretty robust ability to dictate to their developers how and what they must do to run on MacOS, and they produce the compiler and toolchain as well. They seem to do a lot less shimming and other compatibility work on behalf of developers. Modem doesn't work that way, there's tons of existing, immutable hardware across the world with its own quirks and edge cases, all of which you have to support seamlessly.
CamperBob2 3y ago
Qualcomm patents, I suspect.
8fingerlouie 3y ago
A long time ago i used to work at a company that made mobile phones. This was in the days before smartphones, and 3G was a shiny new toy. Back then, many companies would implement the protocols in the phone firmware, as opposed to today where chips usually offload a large part of this. Despite doing our best to implement the GSM Standards[1], the thing at the time was 19,000 pages long, and one of our biggest issues was that our protocol stack would work well with most cell towers, there would always be some carriers that had configured their network just a tiny bit different, and we had to tweak our software to match that. At the time, there were 5 major vendors of GSM cells, and none of them had intepreted the standards identically, so we would also have tweaks to allow for different vendors. I don't remember exactly how many people we employed in our protocol division, but it was more than 100. I do remember that implementing the first version of bluetooth took 19 people almost 2 years, and that, at the time, was a much simpler protocol (it probably still is). I can only imagine the "horrors" that have gone into 4G and 5G since then. These days, all of the above problems are "solved" by simply installing a chip. Qualcomm handles any vendor hardware communication issues, and they're probably "big enough" to also have an impact in the opposite direction, making for a more streamlined protocol landscape. [1]: https://www.etsi.org/standards/get-standards#page=1&search=&title=1&etsiNumber=1&content=0&version=0&onApproval=1&published=1&withdrawn=1&historical=1&isCurrent=1&superseded=1&startDate=1988-01-15&endDate=2023-09-21&harmonized=0&keyword=&TB=372,,376,,377,,378,,513,,496,,439,,649,,651,,653,,654,,655,,656,,535,,536,,537,,538,,622,,539,,575,,373,,379,,380,,3&stdType=&frequency=&mandate=&collection=&sort=1 https://www.etsi.org/standards/get-standards#page=1&search=&...
- grandinj 3y ago
  This. The standard is also truly horrible to read. It's not really designed to be read, as much as it is an after-the-fact description of what somebody has already done. To the point that testing against a very wide variety of base-stations (and the multitudinous variety of configuration options in those base-stations) is mandatory.
  - mike_hearn 3y ago
    Which is presumably hard to impossible without flying around the world with test chips and physically being in those places, as I guess only a handful of carriers can and will reveal all their config settings and software stacks in practice. The more I think about this modem development problem the harder it seems to get. No wonder Apple have struggled and nobody else even seems to try. The amount of tribal knowledge and random hotfixes in the Qualcomm firmware alone must be irreplaceable.
ksec 3y ago
>Intuitively I would’ve guessed the opposite was true. It wouldn't be intuitive if people actually have some basic understanding of how modern wireless network works. Unfortunately even those who work on Hardware, CPU design and embedding programming dont understand that. Let alone 99.99999999% of HN.
- Sporktacular 3y ago
  So, what's the answer?
  - baby_souffle 3y ago
    > So, what's the answer? Probably a mix of things. QCM has a lot of IP/Patents in this space so there are some "intuitive" engineering solutions that ... can't be pursued w/o a license. But even if there was no legal blockers, RF engineering is a _whole other ball game_ compared to the "routine" circuits used in CPUs. I don't just mean from a "well, the schematic sure looks different" perspective, I mean from a "how you build it in the fab" perspective as well. TL;DR: if electricity is magic, RF is black magic.
vdfs 3y ago
> Modem chips are trickier to make than processing chips because they must work seamlessly with 5G wireless networks, as well as the 2G, 3G and 4G networks used in countries around the world, each with its own technological quirks. Apple microprocessors run software programs designed solely for its iPhones and laptops.
- kylehotchkiss 3y ago
  If you have satellite comms for emergencies, maybe the requirement for supporting 2G can slowly be reduced.
gumby 3y ago
Analog is hard, and quite different from digital.* And then you have to work around the patent thicket in an already difficult domain. * Nowadays clock speeds are so fast that you have a lot of analog things to worry about with all these high speed serial lines and on the chips themselves. But the domain constraints are in general simpler, with recovery and reconstruction opportunities available due to things like how you structure your protocols. The same is true in radio (came from radio, actually) but when you have a device operating at arbitrary and continually changing orientations, with all sorts of unknown environments outside you get all sorts of unpredictable multipath, loss, ringing and innumerable other problems to deal with.
- scrlk 3y ago
  > Analog is hard, and quite different from digital. In the infamous words of Bob Widlar [0]: "Every idiot can count to one." [0] For those who don't recognise the name, Widlar was a legendary analog designer - along with Jim Williams and Bob Pease. https://en.wikipedia.org/wiki/Bob_Widlar https://en.wikipedia.org/wiki/Bob_Widlar
deleted 3y ago
[deleted]
ReptileMan 3y ago
For the processors they had Jim Keller
bsder 3y ago
Carriers are complete and utter shit. Getting your modem "certified" with a carrier network requires an absolutely Byzantine set of testing that would stagger your imagination. And the carriers all like it very much since it enforces their monopoly position just like the old "You must use Ma Bell phones on the Ma Bell lines."

What’s the fundamental reason why SOTA modems are more challenging than microprocessors for Apple? Intuitively I would’ve guessed the opposite was true.

by zdyn5 3y ago

What’s the fundamental reason why SOTA modems are more challenging than microprocessors for Apple? Intuitively I would’ve guessed the opposite was true.

lbourdages 3y ago

I would guess lack of expertise? Apple purchased PA Semi a while ago and the team went on to work on their processors. Have they purchased a company specialized in mixed-signal circuit design? That's one of the key differences, a modem contains a lot of analog circuitry and analog is very different from digital.

donavanm 3y ago
PA Semi was 2008 or so, and Intrinsity in 2009-10. In both cases they came with (more or less) working products, an existing relationship, and coherent engineering teams with an active development pipeline. Its fair to say the intel modem folks have a lot of that individually, but Im not clear how much of the whole transferred over. Edit: and the HwEng org already had established VLSI, SoC, and PCB groups shipping products before those acquisitions happened.
kalleboo 3y ago
> Have they purchased a company specialized in mixed-signal circuit design? They bought Intel's modem business, which was originally part of Infineon. Intel had working 4G modems which were only a year or two behind Qualcomm to the point where most users wouldn't notice. But they never seemed to manage to make the jump to 5G.
- ikekkdcjkfke 3y ago
  5G is overrated
  - kalleboo 3y ago
    It may be, but all new network capacity is being built on 5G so a phone without it will suffer more and more in performance, especially in crowded areas/events.
  - xwolfi 3y ago
    5G is absolutely insane. 100Mb/s for 20 USD/mo on a mobile phone in Hong Kong is absolutely mind-blowing. I suppose in low density areas like Tokyo, New York or Paris, it might be slower in some patches ?
    - kalleboo 3y ago
      I typically get around 300-600 Mbps on 5G, but in some areas I've seen speeds up to 1.3 Gbps (on NR, not even mmWave). This is in a Japanese city of pop 300,000
    - drevil-v2 3y ago
      What are you doing on a handheld device screen that would blow your mind once the novelty of seeing the big numbers on speedtest app wore off? Genuinely curious- what can you do on 5G phone that you can’t on your 4G phone?
      - Sporktacular 3y ago
        Run a faster hotspot.
      - elcritch 3y ago
        Upload video, sync photos, backup the phone, watch 4k movies, etc
      - PeterisP 3y ago
        A reasonably frequent usage of this speed is for families to switch over to mobile internet as the primary service for your home, having multiple people watch "TV" and videoconference all while someone is gaming (or dowloading a 40 Gb game) all through a single 5G modem.
      - astrange 3y ago
        Among other things, 5G works better in crowds. And the faster your transfer finishes, the faster you can turn the antenna off and save power.
    - qwertimus 3y ago

wyldfire 3y ago

IMO cellular network protocols are remarkably challenging to understand. Then you add to that various quirks of certain network operators, optimal power consumption and throughput, security. They probably want their design to work as well as the baseline one, and globally.

staticautomatic 3y ago
As someone who used to work occasionally on explaining 3GPP/2 to laypeople, I’d call “remarkably challenging” an understatement.

tech-historian 3y ago

From the article: "Modem chips are trickier to make than processing chips because they must work seamlessly with 5G wireless networks, as well as the 2G, 3G and 4G networks used in countries around the world, each with its own technological quirks. Apple microprocessors run software programs designed solely for its iPhones and laptops." Also: "[Apple's modem] chips were essentially three years behind Qualcomm’s best modem chip. Using them threatened to make iPhone wireless speeds slower than its competitors."

justusw 3y ago
I wonder what some of the regional quirks are, instances where the implementation strays from the standard, but if you don’t do it in quirks mode, you can’t connect to the cellular connection or calls will not go through etc. A sort of woops, non-strict YAML moment, but in telecommunications.

testrun 3y ago

The Apple CPU's architecture is already known (ARM). To iterate from there is probably easier than designing a modem without the basics already designed and ready to go.

secabeen 3y ago
Apple also has a pretty robust ability to dictate to their developers how and what they must do to run on MacOS, and they produce the compiler and toolchain as well. They seem to do a lot less shimming and other compatibility work on behalf of developers. Modem doesn't work that way, there's tons of existing, immutable hardware across the world with its own quirks and edge cases, all of which you have to support seamlessly.

CamperBob2 3y ago

Qualcomm patents, I suspect.

8fingerlouie 3y ago

A long time ago i used to work at a company that made mobile phones. This was in the days before smartphones, and 3G was a shiny new toy. Back then, many companies would implement the protocols in the phone firmware, as opposed to today where chips usually offload a large part of this. Despite doing our best to implement the GSM Standards[1], the thing at the time was 19,000 pages long, and one of our biggest issues was that our protocol stack would work well with most cell towers, there would always be some carriers that had configured their network just a tiny bit different, and we had to tweak our software to match that. At the time, there were 5 major vendors of GSM cells, and none of them had intepreted the standards identically, so we would also have tweaks to allow for different vendors. I don't remember exactly how many people we employed in our protocol division, but it was more than 100. I do remember that implementing the first version of bluetooth took 19 people almost 2 years, and that, at the time, was a much simpler protocol (it probably still is). I can only imagine the "horrors" that have gone into 4G and 5G since then. These days, all of the above problems are "solved" by simply installing a chip. Qualcomm handles any vendor hardware communication issues, and they're probably "big enough" to also have an impact in the opposite direction, making for a more streamlined protocol landscape. [1]: https://www.etsi.org/standards/get-standards#page=1&search=&title=1&etsiNumber=1&content=0&version=0&onApproval=1&published=1&withdrawn=1&historical=1&isCurrent=1&superseded=1&startDate=1988-01-15&endDate=2023-09-21&harmonized=0&keyword=&TB=372,,376,,377,,378,,513,,496,,439,,649,,651,,653,,654,,655,,656,,535,,536,,537,,538,,622,,539,,575,,373,,379,,380,,3&stdType=&frequency=&mandate=&collection=&sort=1 https://www.etsi.org/standards/get-standards#page=1&search=&...

grandinj 3y ago
This. The standard is also truly horrible to read. It's not really designed to be read, as much as it is an after-the-fact description of what somebody has already done. To the point that testing against a very wide variety of base-stations (and the multitudinous variety of configuration options in those base-stations) is mandatory.
- mike_hearn 3y ago
  Which is presumably hard to impossible without flying around the world with test chips and physically being in those places, as I guess only a handful of carriers can and will reveal all their config settings and software stacks in practice. The more I think about this modem development problem the harder it seems to get. No wonder Apple have struggled and nobody else even seems to try. The amount of tribal knowledge and random hotfixes in the Qualcomm firmware alone must be irreplaceable.

ksec 3y ago

>Intuitively I would’ve guessed the opposite was true. It wouldn't be intuitive if people actually have some basic understanding of how modern wireless network works. Unfortunately even those who work on Hardware, CPU design and embedding programming dont understand that. Let alone 99.99999999% of HN.

Sporktacular 3y ago
So, what's the answer?
- baby_souffle 3y ago
  > So, what's the answer? Probably a mix of things. QCM has a lot of IP/Patents in this space so there are some "intuitive" engineering solutions that ... can't be pursued w/o a license. But even if there was no legal blockers, RF engineering is a _whole other ball game_ compared to the "routine" circuits used in CPUs. I don't just mean from a "well, the schematic sure looks different" perspective, I mean from a "how you build it in the fab" perspective as well. TL;DR: if electricity is magic, RF is black magic.

vdfs 3y ago

> Modem chips are trickier to make than processing chips because they must work seamlessly with 5G wireless networks, as well as the 2G, 3G and 4G networks used in countries around the world, each with its own technological quirks. Apple microprocessors run software programs designed solely for its iPhones and laptops.

kylehotchkiss 3y ago
If you have satellite comms for emergencies, maybe the requirement for supporting 2G can slowly be reduced.

gumby 3y ago

Analog is hard, and quite different from digital.* And then you have to work around the patent thicket in an already difficult domain. * Nowadays clock speeds are so fast that you have a lot of analog things to worry about with all these high speed serial lines and on the chips themselves. But the domain constraints are in general simpler, with recovery and reconstruction opportunities available due to things like how you structure your protocols. The same is true in radio (came from radio, actually) but when you have a device operating at arbitrary and continually changing orientations, with all sorts of unknown environments outside you get all sorts of unpredictable multipath, loss, ringing and innumerable other problems to deal with.

scrlk 3y ago
> Analog is hard, and quite different from digital. In the infamous words of Bob Widlar [0]: "Every idiot can count to one." [0] For those who don't recognise the name, Widlar was a legendary analog designer - along with Jim Williams and Bob Pease. https://en.wikipedia.org/wiki/Bob_Widlar https://en.wikipedia.org/wiki/Bob_Widlar

deleted 3y ago

[deleted]

ReptileMan 3y ago

For the processors they had Jim Keller

bsder 3y ago

Carriers are complete and utter shit. Getting your modem "certified" with a carrier network requires an absolutely Byzantine set of testing that would stagger your imagination. And the carriers all like it very much since it enforces their monopoly position just like the old "You must use Ma Bell phones on the Ma Bell lines."