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View all threadsObserving multipath phenomena by transmitting Impulses using NI USRP 2901
Hi all,
I am trying to observe the multi path phenomena by transmitting rectangular
impulses using NI USRP 2901. The duration of impulse is around 5 us and the
idle duration between impulses is around 10m. I expect to receive copies of
the impulse along with the original impulse at the output. Whereas I am
only observing the real impulse at the output and the multi path component
is not being observed. Can anybody guide me so that I may be able to solve
this problem?
Ammar
Hey Ammar,
how do you try to resolve the multi-path components? Have you thought
about the range in which the time spread of your multi-path copies would
fall?
Cheers,
Julian
On 05/16/2017 09:33 AM, Ammar Mahmood via USRP-users wrote:
Hi all,
I am trying to observe the multi path phenomena by transmitting
rectangular impulses using NI USRP 2901. The duration of impulse is
around 5 us and the idle duration between impulses is around 10m. I
expect to receive copies of the impulse along with the original
impulse at the output. Whereas I am only observing the real impulse at
the output and the multi path component is not being observed. Can
anybody guide me so that I may be able to solve this problem?
Ammar
USRP-users mailing list
USRP-users@lists.ettus.com
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--
Julian Arnold, M.Sc.
Institute for Networked Systems
RWTH Aachen University
Kackertstrasse 9
52072 Aachen
Germany
Hey Julian,
Thanks for your response. I have not computed the timespread in which my
multipath copies would fall as I am conducting this experiment in a
scattered environment of lab. I am giving the signal a higher gain (50+db)
so I assume that the multi path component will have higher power than the
noise and I will be able to distinguish it from the noise through it but
till now I have not successfully achieved it.
-Ammar
On Tue, May 16, 2017 at 12:55 PM, Julian Arnold julian@elitecoding.org
wrote:
Hey Ammar,
how do you try to resolve the multi-path components? Have you thought
about the range in which the time spread of your multi-path copies would
fall?
Cheers,
Julian
On 05/16/2017 09:33 AM, Ammar Mahmood via USRP-users wrote:
Hi all,
I am trying to observe the multi path phenomena by transmitting
rectangular impulses using NI USRP 2901. The duration of impulse is
around 5 us and the idle duration between impulses is around 10m. I
expect to receive copies of the impulse along with the original
impulse at the output. Whereas I am only observing the real impulse at
the output and the multi path component is not being observed. Can
anybody guide me so that I may be able to solve this problem?
Ammar
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
--
Julian Arnold, M.Sc.
Institute for Networked Systems
RWTH Aachen University
Kackertstrasse 9
52072 Aachen
Germany
Hey,
so for an indoor environment and frequencies around 1GHz I would suspect
that the RMS delay spread is going to be somewhere below 50ns (which is
tiny compared to your 5us pulse).
Now, you have to think about how to resolve those components with the
limited bandwidth your transceiver is giving you.
Remember, you will not be able to transmit you rectangular puls without
distortion as this would require an infinite bandwidth.
So think about how your received signal will look like and how the
multi-path components would show up?
Cheers,
On 05/16/2017 10:32 AM, Ammar Mahmood wrote:
Hey Julian,
Thanks for your response. I have not computed the timespread in which
my multipath copies would fall as I am conducting this experiment in a
scattered environment of lab. I am giving the signal a higher gain
(50+db) so I assume that the multi path component will have higher
power than the noise and I will be able to distinguish it from the
noise through it but till now I have not successfully achieved it.
-Ammar
On Tue, May 16, 2017 at 12:55 PM, Julian Arnold
<julian@elitecoding.org mailto:julian@elitecoding.org> wrote:
Hey Ammar,
how do you try to resolve the multi-path components? Have you thought
about the range in which the time spread of your multi-path copies
would
fall?
Cheers,
Julian
On 05/16/2017 09:33 AM, Ammar Mahmood via USRP-users wrote:
Hi all,
I am trying to observe the multi path phenomena by transmitting
rectangular impulses using NI USRP 2901. The duration of impulse is
around 5 us and the idle duration between impulses is around 10m. I
expect to receive copies of the impulse along with the original
impulse at the output. Whereas I am only observing the real
impulse at
the output and the multi path component is not being observed. Can
anybody guide me so that I may be able to solve this problem?
Ammar
USRP-users mailing list
USRP-users@lists.ettus.com mailto:USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
<http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com>
--
Julian Arnold, M.Sc.
Institute for Networked Systems
RWTH Aachen University
Kackertstrasse 9
52072 Aachen
Germany
--
Julian Arnold, M.Sc.
Institute for Networked Systems
RWTH Aachen University
Kackertstrasse 9
52072 Aachen
Germany
Hey,
I am thinking to conduct this experiment in an empty room. In this way, I
can better estimate the delay spread of the multi-path component as it will
only by reflection by the walls of the room. Also, using directional
antennas in order to capture the multi-path component in a better way.
Also, I have NI USRP 2943R available with me. Should I go with them or NI
2901 is capable of doing this experiment?
-Ammar
On Tue, May 16, 2017 at 3:24 PM, Julian Arnold julian@elitecoding.org
wrote:
Hey,
so for an indoor environment and frequencies around 1GHz I would suspect
that the RMS delay spread is going to be somewhere below 50ns (which is
tiny compared to your 5us pulse).
Now, you have to think about how to resolve those components with the
limited bandwidth your transceiver is giving you.
Remember, you will not be able to transmit you rectangular puls without
distortion as this would require an infinite bandwidth.
So think about how your received signal will look like and how the
multi-path components would show up?
Cheers,
On 05/16/2017 10:32 AM, Ammar Mahmood wrote:
Hey Julian,
Thanks for your response. I have not computed the timespread in which
my multipath copies would fall as I am conducting this experiment in a
scattered environment of lab. I am giving the signal a higher gain
(50+db) so I assume that the multi path component will have higher
power than the noise and I will be able to distinguish it from the
noise through it but till now I have not successfully achieved it.
-Ammar
On Tue, May 16, 2017 at 12:55 PM, Julian Arnold
<julian@elitecoding.org mailto:julian@elitecoding.org> wrote:
Hey Ammar,
how do you try to resolve the multi-path components? Have you thought
about the range in which the time spread of your multi-path copies
would
fall?
Cheers,
Julian
On 05/16/2017 09:33 AM, Ammar Mahmood via USRP-users wrote:
Hi all,
I am trying to observe the multi path phenomena by transmitting
rectangular impulses using NI USRP 2901. The duration of impulse is
around 5 us and the idle duration between impulses is around 10m. I
expect to receive copies of the impulse along with the original
impulse at the output. Whereas I am only observing the real
impulse at
the output and the multi path component is not being observed. Can
anybody guide me so that I may be able to solve this problem?
Ammar
USRP-users mailing list
USRP-users@lists.ettus.com mailto:USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
<http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com>
--
Julian Arnold, M.Sc.
Institute for Networked Systems
RWTH Aachen University
Kackertstrasse 9
52072 Aachen
Germany
--
Julian Arnold, M.Sc.
Institute for Networked Systems
RWTH Aachen University
Kackertstrasse 9
52072 Aachen
Germany
Hey,
there are multiple ways to resolve multi path components. One popular
way is to use a PN sequence and a sliding correlator to estimate the
channel impulse response.
Here, the resolution would be limited by the bandwidth of the hardware
you are using. The X-series USRPs you have at hand combined with RFNoC
would probably be a good fit here.
What resolution you need totally depends on your requirements. Like I
said, in an indoor environment I would consider an RMS delay spread < 50ns.
However, you could, of course, also use directional antennas to resolve
the multi-path components my their AoA.
Here, the resolution would be limited by the directionality of your antenna.
I think you should first try to come up with a solid strategy of how and
what you want to measure and then start to set up the experiment.
Take, for example, a look at [1] for some background literature.
Let me know if you have any further questions.
[1] http://www2.ece.ohio-state.edu/~schniter/pdf/albornoz_thesis.pdf
Cheers,
On 05/16/2017 03:42 PM, Ammar Mahmood wrote:
Hey,
I am thinking to conduct this experiment in an empty room. In this
way, I can better estimate the delay spread of the multi-path
component as it will only by reflection by the walls of the room.
Also, using directional antennas in order to capture the multi-path
component in a better way. Also, I have NI USRP 2943R available with
me. Should I go with them or NI 2901 is capable of doing this experiment?
-Ammar
On Tue, May 16, 2017 at 3:24 PM, Julian Arnold <julian@elitecoding.org
mailto:julian@elitecoding.org> wrote:
Hey,
so for an indoor environment and frequencies around 1GHz I would
suspect
that the RMS delay spread is going to be somewhere below 50ns
(which is
tiny compared to your 5us pulse).
Now, you have to think about how to resolve those components with the
limited bandwidth your transceiver is giving you.
Remember, you will not be able to transmit you rectangular puls
without
distortion as this would require an infinite bandwidth.
So think about how your received signal will look like and how the
multi-path components would show up?
Cheers,
On 05/16/2017 10:32 AM, Ammar Mahmood wrote:
Hey Julian,
Thanks for your response. I have not computed the timespread in
which
my multipath copies would fall as I am conducting this
experiment in a
scattered environment of lab. I am giving the signal a higher gain
(50+db) so I assume that the multi path component will have higher
power than the noise and I will be able to distinguish it from the
noise through it but till now I have not successfully achieved it.
-Ammar
On Tue, May 16, 2017 at 12:55 PM, Julian Arnold
<julian@elitecoding.org mailto:julian@elitecoding.org
<mailto:julian@elitecoding.org <mailto:julian@elitecoding.org>>>
wrote:
Hey Ammar,
how do you try to resolve the multi-path components? Have
you thought
about the range in which the time spread of your multi-path
copies
would
fall?
Cheers,
Julian
On 05/16/2017 09:33 AM, Ammar Mahmood via USRP-users wrote:
Hi all,
I am trying to observe the multi path phenomena by
transmitting
rectangular impulses using NI USRP 2901. The duration of
impulse is
around 5 us and the idle duration between impulses is
around 10m. I
expect to receive copies of the impulse along with the
original
impulse at the output. Whereas I am only observing the real
impulse at
the output and the multi path component is not being
observed. Can
anybody guide me so that I may be able to solve this problem?
Ammar
USRP-users mailing list
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<mailto:USRP-users@lists.ettus.com>>
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--
Julian Arnold, M.Sc.
Institute for Networked Systems
RWTH Aachen University
Kackertstrasse 9
52072 Aachen
Germany
--
Julian Arnold, M.Sc.
Institute for Networked Systems
RWTH Aachen University
Kackertstrasse 9
52072 Aachen
Germany
--
Julian Arnold, M.Sc.
Institute for Networked Systems
RWTH Aachen University
Kackertstrasse 9
52072 Aachen
Germany