Hi everyone,
Im doing channel estimation in gnu radio narrowband. But the result is
different than I expect.
Im using the example in grc, uhd_tx_dpsk.grc and uhd_rx_dpsk.grc. Send
vector (255,255,255) repeatedly using BPSK. At the receiver, I add a
file sink after the time_recov block and store the data.
Y=X*H +N, the data after time_recov is Y, and in BPSK, when sending 1
is mapped to 1+0j, so X=1+0j. Thus, Y/X is the estimate channel
frequency I get. I plot the absolute value of the channel frequency and
get a figure as in the attachment. But it seems that it has the carrier
frequency with it. It is so well organized and changes regularly. But Im
pretty sure that before the file sink, in the time_recov block, the rrc
filter already take off the carrier frequency.
Has anyone come across the same problem before? Or find any mistakes or
suggestions on my method? Please let me know!
Thank you very much!Ada
I don’t think the RRC filter is used for carrier frequency correction.
In
gnuradio, the FLL filter can be used for CFO correction.
Please correct me if I am wrong.
On Wed, May 29, 2013 at 9:43 PM, yeran [email protected] wrote:
Has anyone come across the same problem before? Or find any mistakes or
Discuss-gnuradio Info Page
–
Alex,
Dreams can come true just believe.
FLL = Frequency lock looping.
The corresponding C++ block is digital_fll_band_edge_cc.
and you can find the usage example in generic_mod_demod.py in
/gnuradio/gr-digtial/python.
There are some discussions within this community before, just search it
for
how to use it properly.
On Wed, May 29, 2013 at 10:07 PM, yeran [email protected] wrote:
Please correct me if I am wrong.
before the file sink, in the time_recov block, the rrc filter already take
Alex,
Dreams can come true just believe.
–
Alex,
Dreams can come true just believe.
Hi Alex,
I have read the generic_mod_demod.py and find the fll block you
mentioned is in freq_recov block, which is before the time_recov block.
However, the file sink I use to collect data is after time_recov block.
So I think in this case, it’s already been through carrier frequency
correction. But as shown in the picture I attached with the original
email, the channel I get still seems to be with carrier frequency.
Please correct me if there is a misunderstanding in my thought!
Thanks! Look forward to your reply!!
Best,Ada
Date: Wed, 29 May 2013 22:27:14 -0500
Subject: Re: [Discuss-gnuradio] channel estimation in gnuradio
narrowband
From: [email protected]
To: [email protected]; [email protected]
FLL = Frequency lock looping. The corresponding C++ block is
digital_fll_band_edge_cc. and you can find the usage example in
generic_mod_demod.py in /gnuradio/gr-digtial/python.
There are some discussions within this community before, just search it
for how to use it properly.
On Wed, May 29, 2013 at 10:07 PM, yeran [email protected] wrote:
Hi Alex,
Thank you for your prompt reply!
But I don’t quite understand what you said about FLL filter for CFO
correction. What is the full name of the FLL filter? In which block?
Thanks! Look forward to your reply!
Ada
Date: Wed, 29 May 2013 21:55:29 -0500
Subject: Re: [Discuss-gnuradio] channel estimation in gnuradio
narrowband
From: [email protected]
To: [email protected]
CC: [email protected]
I don’t think the RRC filter is used for carrier frequency correction.
In gnuradio, the FLL filter can be used for CFO correction. Please
correct me if I am wrong.
On Wed, May 29, 2013 at 9:43 PM, yeran [email protected] wrote:
Hi everyone,
Im doing channel estimation in gnu radio narrowband. But the result is
different than I expect.
Im using the example in grc, uhd_tx_dpsk.grc and uhd_rx_dpsk.grc. Send
vector (255,255,255) repeatedly using BPSK. At the receiver, I add a
file sink after the time_recov block and store the data.
Y=X*H +N, the data after time_recov is Y, and in BPSK, when sending 1
is mapped to 1+0j, so X=1+0j. Thus, Y/X is the estimate channel
frequency I get. I plot the absolute value of the channel frequency and
get a figure as in the attachment. But it seems that it has the carrier
frequency with it. It is so well organized and changes regularly. But Im
pretty sure that before the file sink, in the time_recov block, the rrc
filter already take off the carrier frequency.
Has anyone come across the same problem before? Or find any mistakes or
suggestions on my method? Please let me know!
Thank you very much!
Ada
Discuss-gnuradio mailing list
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
–
Alex,Dreams can come true C just believe.
–
Alex,Dreams can come true C just believe.
Hi Alex,
yes, I’m using the original generic_mod_demod.py, and just adding a
file_sink after the time_recov block, so there is a freq_recov before.
But thanks all the same! 
Ada
Date: Thu, 30 May 2013 00:28:45 -0500
Subject: Re: [Discuss-gnuradio] channel estimation in gnuradio
narrowband
From: [email protected]
To: [email protected]
CC: [email protected]
So, actually, your code already has the freq recov block? If so, I
really have no idea on how to solve your problem.
On Wed, May 29, 2013 at 11:34 PM, yeran [email protected] wrote:
Hi Alex,
I have read the generic_mod_demod.py and find the fll block you
mentioned is in freq_recov block, which is before the time_recov block.
However, the file sink I use to collect data is after time_recov block.
So I think in this case, it’s already been through carrier frequency
correction. But as shown in the picture I attached with the original
email, the channel I get still seems to be with carrier frequency.
Please correct me if there is a misunderstanding in my thought!
Thanks! Look forward to your reply!!
Best,Ada
Date: Wed, 29 May 2013 22:27:14 -0500
Subject: Re: [Discuss-gnuradio] channel estimation in gnuradio
narrowband
From: [email protected]
To: [email protected]; [email protected]
FLL = Frequency lock looping. The corresponding C++ block is
digital_fll_band_edge_cc. and you can find the usage example in
generic_mod_demod.py in /gnuradio/gr-digtial/python.
There are some discussions within this community before, just search it
for how to use it properly.
On Wed, May 29, 2013 at 10:07 PM, yeran [email protected] wrote:
Hi Alex,
Thank you for your prompt reply!
But I don’t quite understand what you said about FLL filter for CFO
correction. What is the full name of the FLL filter? In which block?
Thanks! Look forward to your reply!
Ada
Date: Wed, 29 May 2013 21:55:29 -0500
Subject: Re: [Discuss-gnuradio] channel estimation in gnuradio
narrowband
From: [email protected]
To: [email protected]
CC: [email protected]
I don’t think the RRC filter is used for carrier frequency correction.
In gnuradio, the FLL filter can be used for CFO correction. Please
correct me if I am wrong.
On Wed, May 29, 2013 at 9:43 PM, yeran [email protected] wrote:
Hi everyone,
Im doing channel estimation in gnu radio narrowband. But the result is
different than I expect.
Im using the example in grc, uhd_tx_dpsk.grc and uhd_rx_dpsk.grc. Send
vector (255,255,255) repeatedly using BPSK. At the receiver, I add a
file sink after the time_recov block and store the data.
Y=X*H +N, the data after time_recov is Y, and in BPSK, when sending 1
is mapped to 1+0j, so X=1+0j. Thus, Y/X is the estimate channel
frequency I get. I plot the absolute value of the channel frequency and
get a figure as in the attachment. But it seems that it has the carrier
frequency with it. It is so well organized and changes regularly. But Im
pretty sure that before the file sink, in the time_recov block, the rrc
filter already take off the carrier frequency.
Has anyone come across the same problem before? Or find any mistakes or
suggestions on my method? Please let me know!
Thank you very much!
Ada
Discuss-gnuradio mailing list
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
–
Alex,Dreams can come true C just believe.
–
Alex,Dreams can come true C just believe.
–
Alex,Dreams can come true C just believe.
So, actually, your code already has the freq recov block? If so, I
really
have no idea on how to solve your problem.
On Wed, May 29, 2013 at 11:34 PM, yeran [email protected] wrote:
To: [email protected]; [email protected]
On Wed, May 29, 2013 at 10:07 PM, yeran [email protected] wrote:
Ada
gnuradio, the FLL filter can be used for CFO correction.It is so well organized and changes regularly. But Im pretty sure that
Ada
–
Alex,
Dreams can come true just believe.
yeran wrote in post #1110635:
Hi everyone,
Im doing channel estimation in gnu radio narrowband. But the result is
different than I expect.
Im using the example in grc, uhd_tx_dpsk.grc and uhd_rx_dpsk.grc. Send
vector (255,255,255) repeatedly using BPSK. At the receiver, I add a
file sink after the time_recov block and store the data.
Y=X*H +N, the data after time_recov is Y, and in BPSK, when sending 1
is mapped to 1+0j, so X=1+0j. Thus, Y/X is the estimate channel
frequency I get. I plot the absolute value of the channel frequency and
get a figure as in the attachment. But it seems that it has the carrier
frequency with it. It is so well organized and changes regularly. But Im
pretty sure that before the file sink, in the time_recov block, the rrc
filter already take off the carrier frequency.
Has anyone come across the same problem before? Or find any mistakes or
suggestions on my method? Please let me know!
Thank you very much!Ada
Can you please explain me how to use a file sink to save the data
transmitted and to plot the data to see the channel response. I am doing
CHANNEL ESTIMATION in gnu radio.I think this is the method that i should
follow.Is there any other method in gnu radio for channel
estimation…Please help
Hi yeran,
I am wondering if you have solved this problem?
Best Regards,
On Wed, May 29, 2013 at 9:43 PM, yeran [email protected] wrote:
Has anyone come across the same problem before? Or find any mistakes or
Discuss-gnuradio Info Page
–
Alex,
Dreams can come true just believe.