Re: [Discuss-gnuradio] GNURadio on custom SDR platform / UCLA Zigbee PHY

[Matthias Wilhelm]

Am 10.08.2011 um 16:12 schrieb Martin Flasskamp:

> Thank you very much for your reply! I'll write a GNURadio module for our
> DB-SDR-Hardware to use it together with the UCLA ZigBee implementation.
> 
> As a reference system and maybe for future work we want to buy an
> USRP/USRP2.  Which version do you propose?  The ZigBee code seems to
> have been written for the USRP, but how difficult is it porting it to USRP2?
> 
> The Zigbee poject page ( https://www.cgran.org/wiki/UCLAZigBee ) says
> the code needs GNURadio v3.2. Is it better to use that old version or to
> port it to the current GNUradio v3.3.0? Or does anybody still working on
> it and maybe sharing the code somewhere else besides CGRAN?
> 
> Regards,
> Martin

We used the UCLA code together with the USRP2, it is easy to port. The C++ 
blocks and packet handling in python can be reused completely, changes are 
necessary in the src/example scripts that set up the flow graphs. Basically, 
you have to exchange the source/sink blocks with a USRP2/UHD version, correct 
the sampling rate, and remove/adapt some USRP1 specialties such as choosing a 
subdev (there is only one on the USRP2) or setting the PGA (the functions are 
renamed a bit, e.g., its now called u.set_gain(gain) in UHD). In the same way 
you can integrate the code with your hardware later.

We have only USRP2s, the only reason to go for the USRP1 I can think of is that 
you need two boards simultaneously, e.g., when you want to send and receive at 
the same time and still hope to receive something. I think the RFID code on 
CGRAN still needs the USRP1.  This was also the case with the OpenBTS project 
that implements the GSM air interface, but it seems that it works now for both 
platforms. 

Regarding the GNU Radio version, I just tried to compile the UCLA code and it 
completes with the latest git head, I don't think they the code is depending on 
features of a specific version, it seems more like a "guaranteed to work with 
v3.2" statement. I think we used it with a different version than specified 
some time ago, and it successfully  sent and received 15.4 packets. In any 
case, the effort of porting is to tweak the Makefiles rather than change large 
parts of the code. 

Regards,
Matthias