Re: Peaks when increasing the FFT lenght ofdm example
Hi Johannes, First of all thanks for the quick response and time with my problem. I've made a text file with all specifications of my OFDM example that can be found in the attachments of this mail. Thanks again with your help and anything more just let me know. Best regards, Pedro Viegas Citando Johannes Demel : Hi Pedro, we'd need more info to tell why you observe these peaks. How large are your input packets? Do they span multiple OFDM symbols? How many subcarriers are active? Your peaks hint at some kind of repetition or lot's of zeros. Cheers Johannes On 14.12.21 13:07, Pedro Viegas wrote: Hi everyone, I'm having a problem when I increase the number of carriers from 64 to 512 in the gnuradio OFDM example. When the number of carriers is 512, the complex envelope of the signal in the time domain has some peaks, which I can not have for the test I'm trying to make. Can anyone tell why there are those peaks and how I get rid of them? A possible cause for the peaks, in my opinion, can be the fixed frame len of the header, that is filled with zeros when the FFT size increases, resulting in a peak in the beginning of each frame because of the ifft block. If this is the problem, how can I change that frame len? To better show what I'm saying, there is an image on the attachments of the complex envelope with the peaks. Thanks in advance, Pedro Viegas -- Pedro Viegas DSP Engineer Koala Tech phone: +351 917 354 070 e-mail: p...@koalatech.pt 512 carriers GRC Description: Binary data
How to plot a constellation without symbol decision
Hello to all, I'm using the ofdm rx flowgraph from gr digital to receive a ofdm signal generated by the ofdm tx flowgraph. The transmission is made by an USRP Ettus Research N210 in a loopback setup. In the transmitter side, I make a quantization of the generated signal before transmitting it. At the receiver side, the ofdm frame equalizer block outputs the constellation already decided and I don't want that. I would like to see the constellation without symbol decision, in order to analyze the EVM with the quantization noise. Basically, I woul like to see something like the attached image. I have already tried to explore the c++ code of the ofdm frame equalizer block (https://github.com/gnuradio/gnuradio/blob/master/gr-digital/lib/ofdm_frame_equalizer_vcvc_impl.cc) in order to disable the decision_maker function but I'm not sure if that is the right thing to do. PS -> the quantized constellation in the figure is not in real time with the simulation, that's why I can't use it. Can anyone help me with this? Best Regards, Pedro -- Pedro Viegas DSP Engineer Koala Tech phone: +351 917 354 070 e-mail: p...@koalatech.pt
Re: Ofdm transceiver with more than 16QAM
I don know how can I measure the SNR with QAM modulation. There is only a MPSK SNR probe. Can you tell me how to measure SNR with MQAM? Thanks for your help, Pedro Viegas Citando Marcus Müller : Hi. this is a typical question like I'd ask it when talking a student through a test for a digital comms computer lab. So here's a hint: "Constellations with very many points" don't always work. It has to do with SNR. Can you explain what the problem is with low SNR? Best regards, Marcus On 10.11.20 12:56, p...@koalatech.pt wrote: Hi, I'm trying to make an OFDM transmission of a png file (9.3 kB) with 256QAM with the gnuradio example of OFDM transmitter / receiver. The USRP I'm using is the ettus n210 with the cbx daughter board. With the QPSK and 16QAM modulations it works, but with 64QAM or 256QAM I can´t receive the file, sometimes it receives some packets but most of the time it doesn't receive any byte. Can anyone help me with with this problem? Thanks in advance. Pedro Viegas -- Pedro Viegas Signal Processing Engineer Koala Tech phone: +351 917 354 070 e-mail: p...@koalatech.pt
Ofdm transceiver with more than 16QAM
Hi, I'm trying to make an OFDM transmission of a png file (9.3 kB) with 256QAM with the gnuradio example of OFDM transmitter / receiver. The USRP I'm using is the ettus n210 with the cbx daughter board. With the QPSK and 16QAM modulations it works, but with 64QAM or 256QAM I can´t receive the file, sometimes it receives some packets but most of the time it doesn't receive any byte. Can anyone help me with with this problem? Thanks in advance. Pedro Viegas -- Pedro Viegas Signal Processing Engineer Koala Tech phone: +351 917 354 070 e-mail: p...@koalatech.pt
Re: [Discuss-gnuradio] GSoC 2014 project Wireless Networks In-the-Loop and Channel Sounder
Hi everyone, Following is the link to the my GSOC proposal for the project Wireless Networks in-the-loop. I am looking forward to feedback on the proposal. http://www.ee.iitb.ac.in/student/~achuthpv/GSOC%20Proposal%20WiNeLO.pdf Thanks in Advance Achuth On 17 March 2014 18:04, Otterbach, Nico nico.otterb...@student.kit.eduwrote: Achuth, First of all: I'm sorry for my late reply. Last week I had a talk with some other GR developers and we did a brainstorming about the most import WiNeLo projects at this time. Hence, we all agreed on the fact, that we have to work on the framework itself. As a consequence, I want to propose you another possible project: We need some kind of GUI for the already existing functionality. One aspect (and also a new feature) should be the visualization of the network structure/layout and node distribution itself, where one also should be able to randomly deploy nodes and thus create a network structure. There should something similar to the Oment++-GUI or something like that. I will also update the GSOC/page during the day! Are you still interessted in working on the Wireless Netowrks In-the-Loop project at this point? I really hope so, but I can understand if that doesn't fit to your plans anymore. If you're still interesseted, I will provide you with more detailed information! Best regards Nico Von: discuss-gnuradio-bounces+nico.otterbach=student.kit@gnu.org[discuss-gnuradio-bounces+nico.otterbach= student.kit@gnu.org] im Auftrag von achuth pv [achut...@gmail.com] Gesendet: Samstag, 15. März 2014 19:43 An: discuss-gnuradio@gnu.org Cc: Otterbach, Nico (IIIT) Betreff: Re: [Discuss-gnuradio] GSoC 2014 project Wireless Networks In-the-Loop and Channel Sounder Hi every one, I have certain doubts regarding the Wireless networks in the loop project. The optimization part which is suggested as one of the possible sub projects- is the plan to move the python code to c++ so as to use the VOLK libraries. Which SDR board / daughter board is initially planned to implement. I would also like to know more about the client-server as well as about the server used. Can any one please guide me regarding this project so that I can set up proper goals for the proposal. Thanks in Advance Achuth find me at #gnuradio IRC channel - achuthpv On 4 March 2014 01:35, achuth pv achut...@gmail.commailto: achut...@gmail.com wrote: Hi everyone, My name is Achuth PV, first year Master of Technology student in Communication and Signal Processing, Indian Institute of Technology, Bombay, India. I am really interested to work in the GSoC project Wireless Networks In-the-Loop and Channel Sounder( proposed in 2012 ). = Wireless Networks In-the-Loop The basic idea behind Wireless Networks In-the-Loop (WiNeLo) is to build a GR-based network emulator. This implies the modeling of the underlying SDR hardware, the individual channels interference characteristics, as well as the timing behavior (produce correct amount of noise samples if no node is transmitting). The project already started in 2011 and as a outcome, the basic functionality -- the framework with client-server based sample dispatcher as well as some example hardware channel models -- has already been implemented in the gr-winelo OOT, which will be published on github soon. Seehttp:// video.fosdem.org/2014/AW1125/Sunday/Wireless_Networks_IntheLoop.webm for a quick introdcution to Wireless Networks In-the-Loop. Objectives There are various tasks covering several areas. Possible (sub-)projects are: * (Signal Processing) Implementation of new hardware/channel models like a SDR platform/specific daughterboards or reference channels. * (Optimization Performance) Improve performance of existing implementation (port python code to C/C++, develop new mechanisms to collect distribute samples between several nodes). * (Signal Processing Development Tools) Implementation of new development tools like breakpoints on the air link (pause the entire emulation if certain criteria (BER, SNR, interference/collisions) is fulfilled on the virtual channel/at single nodes). Potential mentor(s) Nico Otterbach = Channel Sounder (Proposed in 2012) Details: Channel sounding describes the process of measuring a multipath propagation channel and obtain information about excess delay, Doppler spread and fading properties. The final product should make use of USRPs for channel sounding (the high timing constraints require use of the FPGA) and provide a complete measurement tool which can be used to gather statistics about mobile communication channels. Knowledge prerequisite: Digital signal processing basics, FPGA basics Access to USRPs required. = My fields of interest are signal processing, wireless and digital communication
Re: [Discuss-gnuradio] GSoC 2014 project Wireless Networks In-the-Loop and Channel Sounder
Hi everyone, Following is the google-melange link to my GSOC proposal for the project Wireless Networks in-the-loop. I am looking forward to feedback on the proposal. http://www.google-melange.com/gsoc/proposal/review/student/google/gsoc2014/achuthpv/5629499534213120 Thanks in Advance Achuth On 21 March 2014 13:47, achuth pv achut...@gmail.com wrote: Hi everyone, Following is the link to the my GSOC proposal for the project Wireless Networks in-the-loop. I am looking forward to feedback on the proposal. http://www.ee.iitb.ac.in/student/~achuthpv/GSOC%20Proposal%20WiNeLO.pdf Thanks in Advance Achuth On 17 March 2014 18:04, Otterbach, Nico nico.otterb...@student.kit.eduwrote: Achuth, First of all: I'm sorry for my late reply. Last week I had a talk with some other GR developers and we did a brainstorming about the most import WiNeLo projects at this time. Hence, we all agreed on the fact, that we have to work on the framework itself. As a consequence, I want to propose you another possible project: We need some kind of GUI for the already existing functionality. One aspect (and also a new feature) should be the visualization of the network structure/layout and node distribution itself, where one also should be able to randomly deploy nodes and thus create a network structure. There should something similar to the Oment++-GUI or something like that. I will also update the GSOC/page during the day! Are you still interessted in working on the Wireless Netowrks In-the-Loop project at this point? I really hope so, but I can understand if that doesn't fit to your plans anymore. If you're still interesseted, I will provide you with more detailed information! Best regards Nico Von: discuss-gnuradio-bounces+nico.otterbach=student.kit@gnu.org[discuss-gnuradio-bounces+nico.otterbach= student.kit@gnu.org] im Auftrag von achuth pv [achut...@gmail.com] Gesendet: Samstag, 15. März 2014 19:43 An: discuss-gnuradio@gnu.org Cc: Otterbach, Nico (IIIT) Betreff: Re: [Discuss-gnuradio] GSoC 2014 project Wireless Networks In-the-Loop and Channel Sounder Hi every one, I have certain doubts regarding the Wireless networks in the loop project. The optimization part which is suggested as one of the possible sub projects- is the plan to move the python code to c++ so as to use the VOLK libraries. Which SDR board / daughter board is initially planned to implement. I would also like to know more about the client-server as well as about the server used. Can any one please guide me regarding this project so that I can set up proper goals for the proposal. Thanks in Advance Achuth find me at #gnuradio IRC channel - achuthpv On 4 March 2014 01:35, achuth pv achut...@gmail.commailto: achut...@gmail.com wrote: Hi everyone, My name is Achuth PV, first year Master of Technology student in Communication and Signal Processing, Indian Institute of Technology, Bombay, India. I am really interested to work in the GSoC project Wireless Networks In-the-Loop and Channel Sounder( proposed in 2012 ). = Wireless Networks In-the-Loop The basic idea behind Wireless Networks In-the-Loop (WiNeLo) is to build a GR-based network emulator. This implies the modeling of the underlying SDR hardware, the individual channels interference characteristics, as well as the timing behavior (produce correct amount of noise samples if no node is transmitting). The project already started in 2011 and as a outcome, the basic functionality -- the framework with client-server based sample dispatcher as well as some example hardware channel models -- has already been implemented in the gr-winelo OOT, which will be published on github soon. Seehttp:// video.fosdem.org/2014/AW1125/Sunday/Wireless_Networks_IntheLoop.webm for a quick introdcution to Wireless Networks In-the-Loop. Objectives There are various tasks covering several areas. Possible (sub-)projects are: * (Signal Processing) Implementation of new hardware/channel models like a SDR platform/specific daughterboards or reference channels. * (Optimization Performance) Improve performance of existing implementation (port python code to C/C++, develop new mechanisms to collect distribute samples between several nodes). * (Signal Processing Development Tools) Implementation of new development tools like breakpoints on the air link (pause the entire emulation if certain criteria (BER, SNR, interference/collisions) is fulfilled on the virtual channel/at single nodes). Potential mentor(s) Nico Otterbach = Channel Sounder (Proposed in 2012) Details: Channel sounding describes the process of measuring a multipath propagation channel and obtain information about excess delay, Doppler spread and fading properties. The final product should make use of USRPs for channel sounding (the high
Re: [Discuss-gnuradio] GSoC 2014 project Wireless Networks In-the-Loop and Channel Sounder
Hi every one, I have certain doubts regarding the Wireless networks in the loop project. The optimization part which is suggested as one of the possible sub projects- is the plan to move the python code to c++ so as to use the VOLK libraries. Which SDR board / daughter board is initially planned to implement. I would also like to know more about the client-server as well as about the server used. Can any one please guide me regarding this project so that I can set up proper goals for the proposal. Thanks in Advance Achuth find me at #gnuradio IRC channel - achuthpv On 4 March 2014 01:35, achuth pv achut...@gmail.com wrote: Hi everyone, My name is Achuth PV, first year Master of Technology student in Communication and Signal Processing, Indian Institute of Technology, Bombay, India. I am really interested to work in the GSoC project Wireless Networks In-the-Loop and Channel Sounder( proposed in 2012 ). = *Wireless Networks In-the-Loop* The basic idea behind Wireless Networks In-the-Loop (WiNeLo) is to build a GR-based network emulator. This implies the modeling of the underlying SDR hardware, the individual channels interference characteristics, as well as the timing behavior (produce correct amount of noise samples if no node is transmitting). The project already started in 2011 and as a outcome, the basic functionality -- the framework with client-server based sample dispatcher as well as some example hardware channel models -- has already been implemented in the gr-winelo OOT, which will be published on github soon. See http://video.fosdem.org/2014/AW1125/Sunday/Wireless_Networks_IntheLoop.webm for a quick introdcution to Wireless Networks In-the-Loop. ObjectivesThere are various tasks covering several areas. Possible (sub-)projects are: - (Signal Processing) Implementation of new hardware/channel models like a SDR platform/specific daughterboards or reference channels. - (Optimization Performance) Improve performance of existing implementation (port python code to C/C++, develop new mechanisms to collect distribute samples between several nodes). - (Signal Processing Development Tools) Implementation of new development tools like breakpoints on the air link (pause the entire emulation if certain criteria (BER, SNR, interference/collisions) is fulfilled on the virtual channel/at single nodes). Potential mentor(s) Nico Otterbach = *Channel Sounder (Proposed in 2012)* *Details*: Channel sounding describes the process of measuring a multipath propagation channel and obtain information about excess delay, Doppler spread and fading properties. The final product should make use of USRPs for channel sounding (the high timing constraints require use of the FPGA) and provide a complete measurement tool which can be used to gather statistics about mobile communication channels. *Knowledge prerequisite:* Digital signal processing basics, FPGA basics *Access to USRPs required.* *=* My fields of interest are signal processing, wireless and digital communication, hardware and software programming and data networks. I am really comfortable in programming using C/C++, java, matlab, assembly language, VHDL and I have understanding of Python, CUDA, git. I am also comfortable in working in Linux. I am a team player and a fast learner and has got good commitment. My B Tech final year project was Implementation and comparison of various DCT architectures on FPGA using VHDL I got exposed to GnuRadio for the first time as a part of a course project in Wireless and Mobile Communication taken as a part of my masters. I want to contribute a lot to the open source world and I want GSoC to be the stepping stone for that. Can any one please tell me how to start working on these projects. Thanks in Advance Achuth ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] GSoC 2014 project Wireless Networks In-the-Loop and Channel Sounder
Thanks Aditya On 4 March 2014 02:02, Aditya Dhananjay adi...@cs.nyu.edu wrote: Hi Achuth, Channel sounding with USRP radios and GNU Radio has been done by some folks at Rutgers and ATT Labs. http://arxiv.org/pdf/1211.4940v1.pdf It might be a good idea to contact Nazmul Islam (CCed) about this project. Good luck. best, aditya On Mon, Mar 3, 2014 at 3:05 PM, achuth pv achut...@gmail.com wrote: Hi everyone, My name is Achuth PV, first year Master of Technology student in Communication and Signal Processing, Indian Institute of Technology, Bombay, India. I am really interested to work in the GSoC project Wireless Networks In-the-Loop and Channel Sounder( proposed in 2012 ). = *Wireless Networks In-the-Loop* The basic idea behind Wireless Networks In-the-Loop (WiNeLo) is to build a GR-based network emulator. This implies the modeling of the underlying SDR hardware, the individual channels interference characteristics, as well as the timing behavior (produce correct amount of noise samples if no node is transmitting). The project already started in 2011 and as a outcome, the basic functionality -- the framework with client-server based sample dispatcher as well as some example hardware channel models -- has already been implemented in the gr-winelo OOT, which will be published on github soon. See http://video.fosdem.org/2014/AW1125/Sunday/Wireless_Networks_IntheLoop.webm for a quick introdcution to Wireless Networks In-the-Loop. ObjectivesThere are various tasks covering several areas. Possible (sub-)projects are: - (Signal Processing) Implementation of new hardware/channel models like a SDR platform/specific daughterboards or reference channels. - (Optimization Performance) Improve performance of existing implementation (port python code to C/C++, develop new mechanisms to collect distribute samples between several nodes). - (Signal Processing Development Tools) Implementation of new development tools like breakpoints on the air link (pause the entire emulation if certain criteria (BER, SNR, interference/collisions) is fulfilled on the virtual channel/at single nodes). Potential mentor(s) Nico Otterbach = *Channel Sounder (Proposed in 2012)* *Details*: Channel sounding describes the process of measuring a multipath propagation channel and obtain information about excess delay, Doppler spread and fading properties. The final product should make use of USRPs for channel sounding (the high timing constraints require use of the FPGA) and provide a complete measurement tool which can be used to gather statistics about mobile communication channels. *Knowledge prerequisite:* Digital signal processing basics, FPGA basics *Access to USRPs required.* *=* My fields of interest are signal processing, wireless and digital communication, hardware and software programming and data networks. I am really comfortable in programming using C/C++, java, matlab, assembly language, VHDL and I have understanding of Python, CUDA, git. I am also comfortable in working in Linux. I am a team player and a fast learner and has got good commitment. My B Tech final year project was Implementation and comparison of various DCT architectures on FPGA using VHDL I got exposed to GnuRadio for the first time as a part of a course project in Wireless and Mobile Communication taken as a part of my masters. I want to contribute a lot to the open source world and I want GSoC to be the stepping stone for that. Can any one please tell me how to start working on these projects. Thanks in Advance Achuth ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
