Forum: GNU Radio Smart Antenna

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Roberto M. (Guest)
on 2007-01-18 13:28
(Received via mailing list)
Hi all

is there anybody that experienced USRP projects with SMART Antenna
technology? If yes, where can I find codes or something else related to
USRP-SMART Antenna?
Thanks a lot

Roberto
Lin HUANG (Guest)
on 2007-01-19 17:29
(Received via mailing list)
Hi Roberto,

I don't think there is code related to Smart Antenna, but many people
are
working on MIMO-USRP. The difference between them is the correlation
between
antennas. If you have antenna array for smart antenna, I think you may
utilize some code of MIMO.

Lin


2007/1/18, Roberto M. <removed_email_address@domain.invalid>:
Roberto M. (Guest)
on 2007-01-21 19:33
(Received via mailing list)
Hi

where cai I find MIMO USRP codes?

10x
R

2007/1/19, Lin HUANG <removed_email_address@domain.invalid>:
Martin D. (Guest)
on 2007-01-22 00:50
(Received via mailing list)
Roberto M. wrote:
> Hi all
>
> is there anybody that experienced USRP projects with SMART Antenna
> technology? If yes, where can I find codes or something else related to
> USRP-SMART Antenna?
> Thanks a lot
I have been experimenting with direction finding and passive radar using
gnuradio and multiple antenna's.
These experiments are on hold for now, due to lack of time, but I hope
to continue with them sometime in the future.

What exactly would you like to do and with how much array-elements.
The simplest smart antenna using usrp/gnuradio I can think of is a smart
transmitter using two antenna's.
The phase-difference you introduce between the two signals, combined
with the positioning of your two antenna's determines the maximum and
minimum gain direction(s) of the whole system.

Introducing a fixed phase difference is just multiplying with a const
complex number.
Phi=wanted phase difference in radians
signal=original signal to transmit
sink1=sink where the first output should go
sink2=sink where the second output should go

phasediff=gr.multiply_const_cc(gr_complex(cos(Phi),sin(Phi))
fg.connect(signal,sink1)
fg.connect(signal,phasediff,sink2)

The same goes for reception:
Phi=expected phase difference in radians

input1=signal from first antenna
input2=signal from second antenna
receiver=reception chain

phasediff=gr.multiply_const_cc(gr_complex(cos(Phi),sin(Phi))
adder=gr.add_cc()
fg.connect(signal1,(adder,0))
fg.connect(signal2,phasediff,(adder,1))
fg.connect(adder,receiver)

If you want to automatically determine the phase-differences and
amplitudes things get much more complicated but can still be done.

I even tested with a very slow correlator and agc which automatically
determined the phase difference of the strongest signal received and
tuned
the two antenna array for maximum sensitivity for this signal.


Greetings,
Martin
Lin HUANG (Guest)
on 2007-01-22 07:54
(Received via mailing list)
In gnuradio-examples/python/multi-antenna or multi_usrp

Lin


2007/1/22, Roberto M. <removed_email_address@domain.invalid>:
This topic is locked and can not be replied to.