I’ve written a bunch of articles over the years on software-defined radio (SDR), which is essentially the art of building electronics that can mimic a particular radio technology via software running on appropriate high-performance or otherwise specialized processors. The idea has obvious appeal – imagine a handset that can be a CDMA, GSM, LTE, Wi-Fi, DVB-H (or other digital broadcast), Bluetooth, or whatever radio, just by firing up the appropriate code on a common hardware platform. Pretty cool, huh?
Technically, yes, absolutely. But in practice, an SDR-based handset may no longer be necessary. It’s my guess that, by 2015 or so, essentially all handsets will need only LTE (with backwards compatibility) and Wi-Fi (802.11n, of course, also with backwards compatibility) – a little WiMAX plus Wi-Fi, OK, sure, but that’s it. So, if, let’s say, 80% of the worlds handsets can be built from a simple chipset that just does LTE and Wi-Fi, SDR in that capacity is of much less interest, although I that expect base stations will still be built fundamentally from SDR. A handset chipset that covers the LTE/Wi-Fi bases should be less expensive than one built from SDR, and consume less power as well.
This is not to say that the many other benefits of SDR – including design flexibility and the ability to fix bugs and add features in the field – aren’t valuable. They are. But these may simply be just too expensive given the need to control costs across the entire wireless WAN value chain, but especially in handsets. So, SDR remains technically interesting, and it may find a place in some implementations, but I’m beginning to doubt that it’s the holy grail of handset design.
