How do built-in wireless modems work?

[MC Morrado]

I was wondering how some smartphones manage to integrate their cellular modems into a single SoC. Do the built-in modems have the same or worse performance than a smartphone with a dedicated cellular modem chip? Explain this to me on a detailed hardware level. Is there a sacrifice and/or tradeoff depending on what hardware configuration is used? Seeing a couple Snapdragon chips (Snapdragon 888) as an example is what interested me in seeing how a whole pocket-sized computer's internals to fit on a single chip no bigger than my thumb's fingernail.

 

Oh, wise nerd cave of wisdom, enlighten me.

[Skiiwee29]

<-- Moved to networking -->

[Eigenvektor]

I mean it's a bit like integration a GPU into a CPU. Smaller node size allows more stuff to be put into less room.

 

Similar to an iGPU the limitation would be that you now need to share bandwidth, power and cooling with the other components.

 

But unlike a GPU, we're not talking about something that requires a ton of resources, so that's not a real concern and a dedicated chip has no real advantage. It simply wastes power and space compared to an integrated solution.

[StDragon]

i'm not an expert in the field of IC design. However my understanding is that through software with layout algorithms and propritary intellectual property, SoCs with built-in modems can perform on par or better than a dedicated cellular modem chip. It really "depends" on a whole host of factors such as process node, power requirements, and overall the electrical engineering as a whole to send/receive RF with the necessary digital analog conversion capabilities.

Apple for example tried develop their own modem only to grovel back to Qualcomm designs. That's a very specific case in which an outside vendor has the experience and knowledge in these matters and not just a simple matter of where to place the modem circuitry. It's rumored again that Apple will try this again with their C1 modem for iPhone 17. Will it finally be as good or better than what Qualcomm can do? Time will tell.