Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
Hi, just a different suggestion - have you tried to determine if there is a frequency offset between the receiving and the sending USRP? I did some tests with the digital/benchmark_?x.py / qpsk code before the recent changes, but for me it worked quite well when I adjusted the center frequency of the transmitter or the receiver by their respective offset, eg: ./benchmark_tx -f 2.40001e9 ... ./benchmark_rx -f 2.4e9 ... To measure the offset, I built simple flowgraph with a constant value as a signal source, which gives just a carrier, which should be (in an ideal world) at the selected center frequency, visible e.g. in usrp_fft.py Hope this helps, Stefan -- Stefan Brüns / Bergstraße 21 / 52062 Aachen mailto:lurch at gmx.li http://www.kawo1.rwth-aachen.de/~lurchi/ phone: +49 241 53809034 mobile: +49 151 50412019 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
On Sat, Dec 6, 2008 at 12:29 PM, Bill Stevenson <[EMAIL PROTECTED]> wrote: > Johnathan, could you tell me the detailed configurations of your setup, for > example, which demo files were you using, what were the arguments you used > for your transmission? I also hope the data I got is useful for your > development. Thank you!!! The likely culprit here is the default values of the frequency/phase tracking loop and bit timing recovery gain parameters. There really isn't a one size fits all value for these. These are configured on the command line of benchmark_rx.py: --costas-alpha=xxx --gain-mu=xxx Try setting the first to 0.05 and the second to 0.001 as a starting point; these are what I use successfully with otherwise default parameters. Unfortunately, tweaking these is a trial and error process; the correct values depend on your USRP crystal stability, receiver signal to noise ratio, and samples per symbol value. -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
From: Bill Stevenson <[EMAIL PROTECTED]> To: Johnathan Corgan <[EMAIL PROTECTED]> Cc: discuss-gnuradio@gnu.org Sent: Thursday, December 4, 2008 9:57:02 PM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio From: Johnathan Corgan <[EMAIL PROTECTED]> To: Bill Stevenson <[EMAIL PROTECTED]> Cc: discuss-gnuradio@gnu.org Sent: Thursday, December 4, 2008 6:25:24 PM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio On Thu, Dec 4, 2008 at 1:04 PM, Bill Stevenson <[EMAIL PROTECTED]> wrote: > -r 400k -s 1500: 50% of the transmitted packets are received, but 0 right. For comparison purposes, can you try using the GMSK modulation? Just remove the '-m dqpsk' from the command line. -Johnathan Johnathan, I tried gmsk and dbpsk once again, the results of PER are shown below: for gmsk: -r 400k -s 200 nearly 100% right -r 400k -s 500 nearly 98% right -r 400k -s 1500 nearly 97% right for dbpsk: all of the cases gave almost 0% PER, which means communication were very good! Johnathan, could you tell me the detailed configurations of your setup, for example, which demo files were you using, what were the arguments you used for your transmission? I also hope the data I got is useful for your development. Thank you!!! Bill Hello, Johnathan, I also checked the new code once again, but could not find any mistake in the code. Actually, the members in my team are mainly focusing on communications or networkings, and we do not have any computer guy. We just want to use USRPs system to realize a new idea in Communication Networking, but the results from dqpsk make us frustrated. Does any other USRP fan have the same problem as us? How could we overcome this problem, and is there any work around that could take effect? Thank you!!! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
From: Johnathan Corgan <[EMAIL PROTECTED]> To: Bill Stevenson <[EMAIL PROTECTED]> Cc: discuss-gnuradio@gnu.org Sent: Thursday, December 4, 2008 6:25:24 PM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio On Thu, Dec 4, 2008 at 1:04 PM, Bill Stevenson <[EMAIL PROTECTED]> wrote: > -r 400k -s 1500: 50% of the transmitted packets are received, but 0 right. For comparison purposes, can you try using the GMSK modulation? Just remove the '-m dqpsk' from the command line. -Johnathan Johnathan, I tried gmsk and dbpsk once again, the results of PER are shown below: for gmsk: -r 400k -s 200 nearly 100% right -r 400k -s 500 nearly 98% right -r 400k -s 1500 nearly 97% right for dbpsk: all of the cases gave almost 0% PER, which means communication were very good! Johnathan, could you tell me the detailed configurations of your setup, for example, which demo files were you using, what were the arguments you used for your transmission? I also hope the data I got is useful for your development. Thank you!!! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
On Thu, Dec 4, 2008 at 1:04 PM, Bill Stevenson <[EMAIL PROTECTED]> wrote: > -r 400k -s 1500: 50% of the transmitted packets are received, but 0 right. For comparison purposes, can you try using the GMSK modulation? Just remove the '-m dqpsk' from the command line. -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
From: Johnathan Corgan <[EMAIL PROTECTED]> To: Bill Stevenson <[EMAIL PROTECTED]> Cc: discuss-gnuradio@gnu.org Sent: Wednesday, December 3, 2008 2:57:55 PM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio Thank you, Johnathan! I did my experimentation again with different configuration. Below are the arguments I used for my experimentation: -r 400k -s 1500: 50% of the transmitted packets are received, but 0 right. The received packet number increased continuously. -r 400k -s 500: 66% of the transmitted packets are received, but 0 right. The received packet number increased continuously. -r 400k -s 300: 71% of the transmitted packets are received, but 0 right. The received packet number increased continuously. -r 400k -s 200: 93.6% of the transmitted packets are received, but 0 right. The received packet number increased irregularly. One USRP is controlled by my laptop (Compaq Presario C700, 1.46GHz Dual-Core Pentium, 1GB RAM), which is used for Tx and another USRP is handled by a desktop (Gateway, 2.40GHz, Core 2 Dual, 2GB RAM), which is used for Rx. The two USRP are 3m apart from each other. The reason why we used 2Mbps for dqpsk case was that when the bit rate is up to 2Mbps, the PER ratio could somehow reach its 'minimum value', and there is no uO sign on my desktop PC, but there was one or two uU signs on my laptop part when s is set to 100. I really cannot figure out why I cannot get dqpsk scheme done when you have successfully verified it works fine in your configuration. I am totally confused, is there anything wrong with my setup described above, Johnathan? I really need guidance. Thank you!!! Bill On Mon, Dec 1, 2008 at 1:07 PM, Bill Stevenson <[EMAIL PROTECTED]> wrote: > python benchmark_tx.py -f 2479M -r 2000k -m dqpsk -s 100 (-s 800 or -s 1500) > python benchmark_rx.py -f 2479M -r 2000k -m dqpsk What is the CPU type and speed you are using? In my experience, data rates above about 500 kbps are difficult to receive on a typical laptop platform due to lack of sufficient CPU cycles. On an Intel Core2 Duo at 2.1 GHz (IBM Thinkpad T60), I can't go above 800 kbps. Your rate of 2 Mbps is likely much too high. Are you seeing any "uO" on your output? -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
On Mon, Dec 1, 2008 at 1:07 PM, Bill Stevenson <[EMAIL PROTECTED]> wrote: > python benchmark_tx.py -f 2479M -r 2000k -m dqpsk -s 100 (-s 800 or -s 1500) > python benchmark_rx.py -f 2479M -r 2000k -m dqpsk What is the CPU type and speed you are using? In my experience, data rates above about 500 kbps are difficult to receive on a typical laptop platform due to lack of sufficient CPU cycles. On an Intel Core2 Duo at 2.1 GHz (IBM Thinkpad T60), I can't go above 800 kbps. Your rate of 2 Mbps is likely much too high. Are you seeing any "uO" on your output? -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
From: Johnathan Corgan <[EMAIL PROTECTED]> To: Bill Stevenson <[EMAIL PROTECTED]> Sent: Thursday, November 27, 2008 3:02:23 AM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio No problem, Johnathan. After reading this, I did my experimentation in several different configurations. The commands I used in the transmitter and receiver side are: python benchmark_tx.py -f 2479M -r 2000k -m dqpsk -s 100 (-s 800 or -s 1500) python benchmark_rx.py -f 2479M -r 2000k -m dqpsk I still got the same result: when packet size is 100, the PER is around 20% no matter what the distance between two USRPs and transmission power are; when packet size is 800, PER is around 50% and when size is the default value, PER is around 66%. This result is the same as that I got before I updated our gnuradio codes. Could you tell me which demo file you used for your configuration, what your configuration looks like and what kind of commands you used for your Tx and Rx part? Thank you so much!!! Bill On Wed, Nov 26, 2008 at 3:39 PM, Bill Stevenson <[EMAIL PROTECTED]> wrote: > Hello, Johnathan. I have implemented the entire codes in the trunk step by > step, but unfortunately this time I cannot receive any correct packets under > the dqpsk modulation scheme even after I set the packet size to 40. > Actually, before I installed the SVN codes, I was able to get 90% correct > packets when I set the packet size to 40 and samples per symbol to 4, but > this time it failed sadly. Is there anything going wrong in your new carrier > offset tracking tactics? Thank you! This code is working correctly in a number of different configurations in my lab. Unfortunately, I will be out of the office for the rest of the week and early next week, so will be unable to assist you further. -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
From: Johnathan Corgan <[EMAIL PROTECTED]> To: Bill Stevenson <[EMAIL PROTECTED]> Cc: discuss-gnuradio@gnu.org Sent: Wednesday, November 26, 2008 9:28:05 AM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio On Tue, Nov 25, 2008 at 8:46 PM, Bill Stevenson <[EMAIL PROTECTED]> wrote: > Thank you, Johnathan. Anyway, I would like to use svn and download the fixed > code from the trunk software! Do I just need to type in the command: > > $ svn co http://gnuradio.org/svn/gnuradio/trunk gnuradio > in the terminal? Yes. > But, is there anything else I should do after downloading the code? Please read: http://gnuradio.org/trac/wiki/BuildGuide > One more question I forgot is what kind of risk that might happen to me > after I updated the trunk code? Thank you! The trunk release of software changes frequently, and doesn't always maintain backwards compatibility with existing code. At this point, releases 3.1.x are getting old, and the trunk has many more features. Since we are nearing release 3.2, however, there won't be much more churn. -Johnathan Hello, Johnathan. I have implemented the entire codes in the trunk step by step, but unfortunately this time I cannot receive any correct packets under the dqpsk modulation scheme even after I set the packet size to 40. Actually, before I installed the SVN codes, I was able to get 90% correct packets when I set the packet size to 40 and samples per symbol to 4, but this time it failed sadly. Is there anything going wrong in your new carrier offset tracking tactics? Thank you! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
From: Johnathan Corgan <[EMAIL PROTECTED]> To: Bill Stevenson <[EMAIL PROTECTED]> Cc: discuss-gnuradio@gnu.org Sent: Wednesday, November 26, 2008 9:28:05 AM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio On Tue, Nov 25, 2008 at 8:46 PM, Bill Stevenson <[EMAIL PROTECTED]> wrote: > Thank you, Johnathan. Anyway, I would like to use svn and download the fixed > code from the trunk software! Do I just need to type in the command: > > $ svn co http://gnuradio.org/svn/gnuradio/trunk gnuradio > in the terminal? Yes. > But, is there anything else I should do after downloading the code? Please read: http://gnuradio.org/trac/wiki/BuildGuide > One more question I forgot is what kind of risk that might happen to me > after I updated the trunk code? Thank you! The trunk release of software changes frequently, and doesn't always maintain backwards compatibility with existing code. At this point, releases 3.1.x are getting old, and the trunk has many more features. Since we are nearing release 3.2, however, there won't be much more churn. -Johnathan Thank you so much, Johnathan. I really appreciate your patience! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
On Tue, Nov 25, 2008 at 8:46 PM, Bill Stevenson <[EMAIL PROTECTED]> wrote: > Thank you, Johnathan. Anyway, I would like to use svn and download the fixed > code from the trunk software! Do I just need to type in the command: > > $ svn co http://gnuradio.org/svn/gnuradio/trunk gnuradio > in the terminal? Yes. > But, is there anything else I should do after downloading the code? Please read: http://gnuradio.org/trac/wiki/BuildGuide > One more question I forgot is what kind of risk that might happen to me > after I updated the trunk code? Thank you! The trunk release of software changes frequently, and doesn't always maintain backwards compatibility with existing code. At this point, releases 3.1.x are getting old, and the trunk has many more features. Since we are nearing release 3.2, however, there won't be much more churn. -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
From: Bill Stevenson <[EMAIL PROTECTED]> To: Johnathan Corgan <[EMAIL PROTECTED]> Cc: discuss-gnuradio@gnu.org Sent: Tuesday, November 25, 2008 11:43:30 PM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio From: Johnathan Corgan <[EMAIL PROTECTED]> To: Bill Stevenson <[EMAIL PROTECTED]> Sent: Tuesday, November 25, 2008 11:29:06 PM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio On Tue, 2008-11-25 at 18:43 -0800, Bill Stevenson wrote: > OMG!!! Thank you for your information, it will be really helpful!!! I > will update my code soon. For updating, do I just need to download the > gnuradio-3.1.3.tar.gz and rebuild it? Thank you!!! I'm sorry, I hadn't realized you were using the official release. I haven't checked yet whether the bug that was fixed on our "trunk" software branch exists in that version, so I don't know if it affected you. In any case, unless you are willing to use svn and download from our trunk software, you won't see an update until 3.1.4 is released. -Johnathan Thank you, Johnathan. Anyway, I would like to use svn and download the fixed code from the trunk software! Do I just need to type in the command: $ svn co http://gnuradio.org/svn/gnuradio/trunk gnuradio in the terminal? But, is there anything else I should do after downloading the code? I would like to devote to the development of our gnuradio code and I am not scared of sacrificing! Bill One more question I forgot is what kind of risk that might happen to me after I updated the trunk code? Thank you! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
From: Johnathan Corgan <[EMAIL PROTECTED]> To: Bill Stevenson <[EMAIL PROTECTED]> Sent: Tuesday, November 25, 2008 11:29:06 PM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio On Tue, 2008-11-25 at 18:43 -0800, Bill Stevenson wrote: > OMG!!! Thank you for your information, it will be really helpful!!! I > will update my code soon. For updating, do I just need to download the > gnuradio-3.1.3.tar.gz and rebuild it? Thank you!!! I'm sorry, I hadn't realized you were using the official release. I haven't checked yet whether the bug that was fixed on our "trunk" software branch exists in that version, so I don't know if it affected you. In any case, unless you are willing to use svn and download from our trunk software, you won't see an update until 3.1.4 is released. -Johnathan Thank you, Johnathan. Anyway, I would like to use svn and download the fixed code from the trunk software! Do I just need to type in the command: $ svn co http://gnuradio.org/svn/gnuradio/trunk gnuradio in the terminal? But, is there anything else I should do after downloading the code? I would like to devote to the development of our gnuradio code and I am not scared of sacrificing! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
On Tue, 2008-11-25 at 20:29 -0800, Johnathan Corgan wrote: > On Tue, 2008-11-25 at 18:43 -0800, Bill Stevenson wrote: > > > OMG!!! Thank you for your information, it will be really helpful!!! I > > will update my code soon. For updating, do I just need to download the > > gnuradio-3.1.3.tar.gz and rebuild it? Thank you!!! > > I'm sorry, I hadn't realized you were using the official release. I > haven't checked yet whether the bug that was fixed on our "trunk" > software branch exists in that version, so I don't know if it affected > you. > > In any case, unless you are willing to use svn and download from our > trunk software, you won't see an update until 3.1.4 is released. Forgot to copy the list on this. -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
- Forwarded Message From: Bill Stevenson <[EMAIL PROTECTED]> To: Johnathan Corgan <[EMAIL PROTECTED]> Sent: Tuesday, November 25, 2008 9:43:28 PM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio From: Johnathan Corgan <[EMAIL PROTECTED]> To: Bill Stevenson <[EMAIL PROTECTED]> Cc: discuss-gnuradio@gnu.org Sent: Tuesday, November 25, 2008 6:13:05 PM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio On Tue, 2008-11-25 at 14:55 -0800, Bill Stevenson wrote: > Is the dqpsk modulation scheme in gnuradio working fine? Bill, there was a recent (yesterday) update to the qpsk demodulator code that fixed an issue with the carrier offset tracking. Could you please update to the most recent trunk code and retry your tests? -Johnathan OMG!!! Thank you for your information, it will be really helpful!!! I will update my code soon. For updating, do I just need to download the gnuradio-3.1.3.tar.gz and rebuild it? Thank you!!! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
- Forwarded Message From: Bill Stevenson <[EMAIL PROTECTED]> To: Zenny Zhang <[EMAIL PROTECTED]> Sent: Tuesday, November 25, 2008 9:47:40 PM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio From: Zenny Zhang <[EMAIL PROTECTED]> To: Bill Stevenson <[EMAIL PROTECTED]> Sent: Tuesday, November 25, 2008 8:15:20 PM Subject: Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio Bill, > with two USRP 5 feet apart and the rssi values I tested at the receiver side I think 5 feet is a bit too close. You may actually want to separate the two usrps by at least 30 feet if you want to check the PER witrh regard to signal power. Zenny Thank you, Zenny. Actually we had changed the distance between them from 40 feet to 1 feet. But we could get nothing but the same result. I think Johnathan is right, if there were an error in the qpsk demodulator, that must be in the synchronization part! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] a report on dqpsk modulation in gnuradio
On Tue, 2008-11-25 at 14:55 -0800, Bill Stevenson wrote: > Is the dqpsk modulation scheme in gnuradio working fine? Bill, there was a recent (yesterday) update to the qpsk demodulator code that fixed an issue with the carrier offset tracking. Could you please update to the most recent trunk code and retry your tests? -Johnathan ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] a report on dqpsk modulation in gnuradio
Hello, everyone! I am working on using USRP to realize mutirate transmission. I have spent these two days trying to transmit data with dqpsk modulation scheme, and the file I used is python/digital/benchmark_tx.py and benchmark_rx.py. Below is the conclusion I could reach based on the data I got: 1, I changed the tx-amplitude to different values ranging from 1000 to 12000 with two USRP 5 feet apart and the rssi values I tested at the receiver side are quite great, but no matter the tx-amplitude was the minimum value or the maximum value, the PER was CONSTANT which was arount 12%. While I was doing these experiments, the size of the packet was set to 40 which was actually too small. 2, While from the experiments I described above we know the PER was not changing with the transmission power, after I changed the size of the packet to 100, the PER was changed to 30%, which was still a CONSTANT level. After I changed the number of samples per symbol to 4, the PER was decreased to 20%. So, it looks like that if the transmission power is large enough, the PER of dqpsk modulaiton scheme in gnuradio is only related to the packet size and the samples per symbol, which means dqpsk modulation scheme is not functioning well in gnuradio, am I right? Has anybody come across the same problem as me? Is the dqpsk modulation scheme in gnuradio working fine? Can we use that in our experiment? What kind of workaround I should do for the dqpsk if it is proved that dqpsk cannot work as well as dbpsk? Thanks a lot for all!!! Bill ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
