.@gnu.org] On Behalf Of
> Martin Braun
> Sent: Tuesday, March 3, 2015 5:26 PM
> To: Pengyu Zhang
> Cc: Discuss-gnuradio@gnu.org
> Subject: Re: [Discuss-gnuradio] mimo beam forming on USRP
>
> Can you give us some details (frequency, number of antennas) that you want
> to hav
On 03.03.2015 08:41, Pengyu Zhang wrote:
Martin - I am thinking about doing beam forming around 900MHz. The
number of antennas that I want to use is around 8x8. I am thinking about
using USRP N210+SBX+OctoClock-G suggested by ettus. But not sure how
much phase mis-alignment will I observe.
In t
Martin - I am thinking about doing beam forming around 900MHz. The number
of antennas that I want to use is around 8x8. I am thinking about using
USRP N210+SBX+OctoClock-G suggested by ettus. But not sure how much phase
mis-alignment will I observe.
Marcus - Thanks for the tips. Maybe I should loo
Pengyu:
I think people tend to do it differently, depending on the particular
application. In radio astronomy, they typically point the array at a
well-characterized "calibrator source" and make phase measurements, and
then tweak based on known baseline geometries.
For commercial MIMO, using
Marcus - I am thinking about sending a training signal using one TX antenna
and figure out the phases of other antennas by looking at the maximum
correlation. Does this sound like a reasonable solution for a practical
mimo system?
On Tue, Mar 3, 2015 at 11:44 AM, wrote:
> Pengyu:
>
> I think pe
Can you give us some details (frequency, number of antennas) that you
want to have?
A lot of people have done MIMO with USRPs, up to 100x100 antennas, so
there is some precedent. For beam forming, you'll need very good phase
alignment, depending on what you're planning to set up. This is alway
Indeed, I should have emphasized that despite having features like
"phase resynch", in any *practical* phased-array, you'll still need some
mechanism for calibrating the phase centers of all your antenna.
Differential environmental factors can, for example, affect the phasing
of the antenna feed
If you use the phase-resynch feature of the SBX card, and you have
common refclock and 1PPS across all your USRPs in the array,
then you should be OK.
In *general*, synthesized downconverters use fractional-N synthesizers
where their starting phase after a re-tune is random with respect to an
Hi Guys,
I am planning to build a mimo system which supports beam forming. Is USRP a
good platform for my target? I do not want to use WARP because I need to
operate at frequencies lower than 2.4GHz.
A potential problem of USRP is phase alignment. As the following doc
suggests, phase alignment ca
