Smart Antenna

GNU Radio
1

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

2

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. [email protected]:

3

Hi

where cai I find MIMO USRP codes?

10x
R

2007/1/19, Lin HUANG [email protected]:

4

In gnuradio-examples/python/multi-antenna or multi_usrp

Lin

2007/1/22, Roberto M. [email protected]:

5

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