Forum: GNU Radio Channel Impulse Response

Hi
I want to find *"channel impulse response"* for my project using 
sounding
techniques
I came to know about the 'gr-sounder' application which does just the 
thing
and was implemented in previous versions of gnuradio. I have version 
3.6.0

how can I use this app for my purpose?
any help is appreciated

Thanks in advance



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On Fri, Nov 16, 2012 at 12:30 PM, daviko <david.ldh@gmail.com> wrote:


> I came to know about the 'gr-sounder' application which does just the thing
> and was implemented in previous versions of gnuradio. I have version 3.6.0
>
> how can I use this app for my purpose?
> any help is appreciated
>

The gr-sounder app was a custom FPGA implementation based off the 
obsolete
GNU Radio libusrp2 package for USRP2.  It would have to reimplemented 
from
scratch using the current UHD package from Ettus Research.

The use of the FPGA was to enable the sounding waveform to cover a wider
bandwidth than could be sent over the GbE transport for processing on 
the
PC.  If your channel is narrow enough, you could implement the same
algorithm in GNU Radio.  The transmitter was sending BPSK modulated PN
sequences and the receiver was calculating correlation at successive 
time
lags to estimate the channel impulse response.

Johnathan

Hello Daviko,

I used gnuradio in channel sounding experiments during the summer. I did
not use gr-sounder. Rather, I designed my own transmitter and receiver
block diagrams using GRC.

You can do both sliding correlator and frequency domain channel sounding
using GNUradio. Sliding correlator method directly generates the channel
impulse response. Frequency domain sounding allows you to find the 
impulse
response through inverse FFT procedure. There might be other methods 
that I
am unaware of.

In general, the frequency domain channel sounding method gives you the
channel strengths at different carrier frequencies.Let's say, your 
desired
frequency band is 700-720 MHz region. You can transmit a sinusoid from 
the
transmitter that repeatedly hops at 700, 701, 702, ..., 720, 700, 701, 
.. ,
720 MHz. Your receiver's carrier frequency should hop repeatedly in the
same list. If you can time synchronize your Tx & Rx, you will know the 
path
loss by taking FFT and observing the strength of the floating points in 
the
desired FFT bin.

Thanks,

Nazmul


On Fri, Nov 16, 2012 at 3:30 PM, daviko <david.ldh@gmail.com> wrote:

>
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>



--
Muhammad Nazmul Islam

Graduate Student
Electrical & Computer Engineering
Wireless Information & Networking Laboratory
Rutgers, USA.

Thanks  a lot

I'll try to implement these techniques, and If I can't do that ... Can 
you
help me to achieve it?



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