[hpsdr] Link to video of Chris Testa's FDIM talk on SDRs

[Chris Testa]

Mike,

I don't think we'll be able to re-use anything from the cell baseband
modems from Qualcomm or Intel.  They are all under heavy NDA, and we won't
be able to release Open Source modems built ontop of their hardware.  We
can't even get a compiler for the Hexagon DSP, which is the core building
block of Qualcomm's baseband modems.

Furthermore, their transceiver chips seem to be very specialized for cell
modes alone, which are very different from what we do on Amateur bands. Or
at least, that's as much as I can tell from the few low-res images that
have leaked onto the web about how their architectures work.

That's why I started my project.  To build a baseband modem + transceiver
that meets the power and size requirements of what's in a smartphone, but
intended for narrower-band Amateur modes, on Ham bands.  Imagine a modem
app store, where FreeDV, PSK31, etc. can be installed and updated without
any physical modification to your smart-HT.

It will definitely cost more $$$ and man hours to develop the platform, but
an Open Source stack means we can do things that a smartphone could never
dream of doing.  I think the tradeoff is worth it.

Chris


On Tue, May 20, 2014 at 2:07 PM, Shirley Márquez Dúlcey <mark at buttery.org>wrote:

> ***** High Performance Software Defined Radio Discussion List *****
>
> > This is an awesome session! Just finished watching it. Given the
> broadband nature of the Smartphone modems, would it be practical to recode
> an existing on-board modem to run 23 cm using non-cellular protocols, thus
> turning a Smartphone into a Ham radio? Maybe that's where you were headed
> (I am not very focused today for another reason), but I mean this in the
> sense of all existing hardware, no soldering iron required.
>
> 23cm is a long way away from the cellphone bands. (The closest
> available bands on a typical cellphone are the 900MHz band used
> outside the Americas and the 1700MHz AWS band that T-Mobile USA uses.)
> It's unlikely that the transmitters and antennas in a smartphone are
> sufficiently broadband to cover it well. The 33cm ham band that we
> have in the US has more potential, as it's actually one of the bands
> covered by your smartphone if it has worldwide capability, but sadly
> there is no allocation in that area of the spectrum outside ITU region
> 2 so European and Asian hams don't get to play there.
>
> A further problem is that a lot of the radio behavior is done in
> firmware on the RF chip, or the RF portion of the SoC on the phones
> where all the functions are combined on one big chip. It's not under
> direct control of the primary CPU, nor is there any defined way to
> reprogram the RF chip so it would have to be a reverse engineering
> effort.
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