Re: [Discuss-gnuradio] OFDM with continuous pilots but bursty data

Hi Alex - The default OFDM Rx is fully asynchronous: It tries to detect the packet preamble on a packet by packet basis only, without using any knowledge of historical successful packet detection. I don't think GR provides a synchronous receiver, and I don't know of one in any GR out of tree (OO

Re: [Discuss-gnuradio] OFDM Mod Block - how is it working?

On Tue, 09 Jul 2019 at 17:42:11 +0200, lilijobo1 lilijobo1 wrote: > The thing is that I don't really get how the parameters > "occupied tones" and the "FFT length" work in that case. > Is the occupied tones equal to the numer of subcarriers? If yes where do get > to know the subcarrier spacing b

Re: [Discuss-gnuradio] OFDM

Hi Farid - I'll reply off list since this is pretty technical; we can summarize back on list if appropriate. - MLD On Sat, Jun 8, 2019, at 1:19 PM, farid mihoub wrote: > Hello, > I am trying to change the OFDM_tx_rx payload modulation by a custom 64kQAM, > I implemented the block in several ways,

Re: [Discuss-gnuradio] OFDM cyclic prefix

It's telling you there's a mismatch in the vector size (based on the FFT length) between the FFT block and the Cyclic Prefixer block. It appears you have the FFT block set to 512/8 = 64 and the Cyclic Prefixer block set to 8/8 = 1. Unless you're just writing this block as an exercise, if you s

Re: [Discuss-gnuradio] OFDM Frequency Spacing

Hi ARob, You're right to presume that – because that's how the math behind the DFT works out! So, no, you can't change that. What you can do, of course, make a system with the correct resulting sampling rate (as calculated from desired spacing times number of bins), and just resample that to the

Re: [Discuss-gnuradio] OFDM TX/RX PAPR

How do you reduce the PAPR with existing block in GRC ? I've tried with Scrambler->Encoder CCSDS->Interleaver but it doesn't seems to work. I'm still not having any signal at the output of the OFDM receiver. Guillaume Le 27/03/2018 à 11:58, Ron Economos a écrit : Yes, I think the whitener d

Re: [Discuss-gnuradio] OFDM TX/RX

Yes, I think the whitener does the trick. If you plot the PAPR of band limited white noise, it's pretty much the same curve. Ron On 03/27/2018 02:36 AM, Müller, Marcus (CEL) wrote: Oooh, that's a nice plot! This is way better than I would have anticipated. Can I attribute that to awesome white

Re: [Discuss-gnuradio] OFDM TX/RX

Oooh, that's a nice plot! This is way better than I would have anticipated. Can I attribute that to awesome whitening properties of the code itself and following scramblers/interleavers? Marcus On Tue, 2018-03-27 at 02:31 -0700, Ron Economos wrote: > CCDF (Complementary Cumulative Distribution Fun

Re: [Discuss-gnuradio] OFDM TX/RX

On Fri, 2018-03-23 at 14:21 -0700, Martin Braun wrote: > If you've > increased the number of carriers, PAPR also goes up (a bit). Yep, by the same factor as you increase the number of carriers (proof idea: time-symbol with worst PAPR is the discrete dirac over the vector of FFT length N. That has

Re: [Discuss-gnuradio] OFDM TX/RX

On 03/16/2018 09:33 AM, guillaume.toc...@orange.com wrote: > Hello all, > > I want to make a flow graph for transmitting and receiving OFDM > modulated data. To be precise, I want to do a LTE-M "like" > transmission/reception, so I am trying to transmit data with a BW of > 1.08 MHz OFDM. > To do s

Re: [Discuss-gnuradio] OFDM channel tap questions

Hi Bob, Thanks for your detailed explanation. I figured out the causes for non-unity channel taps in my case. One is I didn’t consider normalization. Second, it was because that the Schmidl-Cox sync has a metric plateau. Imperfect synchronization gave me the phase rotation. Regards, Edwin S

Re: [Discuss-gnuradio] OFDM channel tap questions

Orthogonality (as the O in OFDM) guarantees a fixed phase relationship for every symbol unless a pattern is introduced in an effort to reduce peak to average power ratio (which I do not believe is happening here). PAPR is bane of OFDM and much research has gone in to reduce this problem which requ

Re: [Discuss-gnuradio] OFDM channel tap questions

Ah, normalization was the secret. The phase offset is there because the subcarriers frequencies each look like a phasor that keeps moving (at a rate relative to its offset). You want to predict what the phase will be at the next symbol. On 01/12/2018 01:59 PM, edwin wrote: Hi Jeff, I just fo

Re: [Discuss-gnuradio] OFDM channel tap questions

Hi Jeff, I just found out that if I normalize these taps by the FFT number(64 in this case), they have magnitude of 1! Now my questions are: Why are there phase offset? The phase offset for each subchannel seems different. Is it because of imperfect synchronization? Regards, Edwin _

Re: [Discuss-gnuradio] OFDM channel tap questions

I have to agree with you, and I don't understand what's going on. It looks like the magnitude of the taps should be 1.0, even if there's a phase offset. On 01/11/2018 03:53 PM, edwin wrote: Hi Jeff, Thanks for the reply. What you said about the noise makes sense. However, even if I turn the

Re: [Discuss-gnuradio] OFDM channel tap questions

Hi Jeff, Thanks for the reply. What you said about the noise makes sense. However, even if I turn the noise off, I still get the weired taps: Offset: 2112  Source: n/a Key: ofdm_sync_chan_taps   Value: #[(0,0) (0,0) (0,0) (0,0) (0,0) (0,0) (35.5567,-53.2143) (-6.27313,-63.6921) (-45.255,

Re: [Discuss-gnuradio] OFDM channel tap questions

Hmm, that wasn't the whole answer. After reading the code a little more, it looks like the taps are a function of the sync symbols too, not just the channel. for (int i = loop_start; i < loop_end; i++) { if ((d_ref_sym[i-carr_offset] != gr_complex(0, 0))) { taps[i-carr_o

Re: [Discuss-gnuradio] OFDM channel tap questions

Noise has some bias and structure when measured over a short period. You can see this on a FFT display, where larger transforms give you a smoother noise floor. You'll notice that the taps change randomly with every packet as the estimator adjusts to the noise. On 01/10/2018 04:59 PM, Edwin Li

Re: [Discuss-gnuradio] OFDM frame equalizer length tag

Hi Alice - If I had to guess, it would be that the tag for the frame_equalizer_alix block is "frame_len", while that for the Pseudo- Random Generator is "frame len" ... without the "_" joining the words. Or, that's what it looks like in the image. The tagged_stream_block is picky about these names;

Re: [Discuss-gnuradio] OFDM Preamble

Hi Adhitha, I haven't used the "OFDM Insert Preamble" module before. But in my understanding, in tx_ofdm.grc, "OFDM Carrier Allocator" does the job of "OFDM insert preamble". It uses "sync word" instead of "preamble". I think they are the same thing. As for FFT length, keep it the same as your oth

Re: [Discuss-gnuradio] OFDM Channel Equalisation not unity for perfect channel

Hi again, My current suspicion is that there is a triggering delay produced by the *Schmidl & Cox OFDM Sync* block that isn't accounted for by the *delay* block currently running in parallel to it in the flowgraph (delays samples going to the header/payload demux until the trigger point is found i

Re: [Discuss-gnuradio] OFDM implementation for high data rates

There's the DVB-T transmitter and receiver in the Digital Television component of GNU Radio. It's capable of 31.6 Mbps in a standard 8 MHz bandwidth. (and can be used at higher bandwidths). I have some OOT modules that allow sending IP packets over DVB. Note that these modules only implement t

Re: [Discuss-gnuradio] OFDM/GR-IEEE802-11

Understood. Thanks! On Fri, Mar 31, 2017 at 2:32 PM, Marcus Müller wrote: > Depends on where you are. But usually, no. > > On 31.03.2017 19:54, Thomas Wilkinson wrote: > > Legally, I can perform tests within ISM bands. Correct? > > On Fri, Mar 31, 2017 at 1:14 PM, Martin Braun wrote: > >> You c

Re: [Discuss-gnuradio] OFDM/GR-IEEE802-11

Depends on where you are. But usually, no. On 31.03.2017 19:54, Thomas Wilkinson wrote: > Legally, I can perform tests within ISM bands. Correct? > > On Fri, Mar 31, 2017 at 1:14 PM, Martin Braun > wrote: > > You can change the frequency technically. Legally, we c

Re: [Discuss-gnuradio] OFDM/GR-IEEE802-11

Legally, I can perform tests within ISM bands. Correct? On Fri, Mar 31, 2017 at 1:14 PM, Martin Braun wrote: > You can change the frequency technically. Legally, we can't give you > advice here other than to follow the rules. > > Cheers, > Martin > > On 03/30/2017 09:52 AM, Thomas Wilkinson wrot

Re: [Discuss-gnuradio] OFDM/GR-IEEE802-11

You can change the frequency technically. Legally, we can't give you advice here other than to follow the rules. Cheers, Martin On 03/30/2017 09:52 AM, Thomas Wilkinson wrote: > > Please forgive me as I am new to SDRs and DSP. > > I am interested in development of a radio link using two B210s

Re: [Discuss-gnuradio] OFDM receiver

Hi Muhammad, sadly, it's not very clear what you're asking about. * Which flow graph are you referring to? * What is your precise problem, and what have you tried to solve it so far? How can we help you with that? Best regards, Marcus On 02/22/2017 02:05 PM, MUHAMMAD AHMAD wrote: > How can I r

Re: [Discuss-gnuradio] OFDM channel estimation

On 10/04/2016 06:25 AM, Andreas Weinand wrote: > Hello, > > i'm currently dealing with OFDM channel estimation and try to read out > the estimated values for this purpose. It works when i take the ones > that are given by the tag debug block (Key: ofdm_sync_chan_taps). But > somehow the values loo

Re: [Discuss-gnuradio] OFDM IFFT calculate

Ah, forgot to actually cite one thing: On 30.05.2016 14:49, Marcus Müller wrote: > >> I can't find its' implementation in anywhere so that I can't >> understand what happen in this function. > A DFT is performed, by calling the fftwf_execute function of the FFTw > library, which really, just execu

Re: [Discuss-gnuradio] OFDM IFFT calculate

Hi SangHyuk On 30.05.2016 14:25, SangHyuk Kim wrote: > Hi all, > > The file, /gr-fft/lib/fft_vcc_fftw.cc(http://goo.gl/X8WNPh), No need to use URL shorteners in Emails. Why are you using a revision of that file from 2012? That is not what you should do. Select "branch: Master" from the drop-down m

Re: [Discuss-gnuradio] OFDM Packets and Frames into Tagged Stream Block?

A quick hack would be to throw down a block that renames certain tags. You'd have to write that block, but it would consist of a memcpy() for the data and a conditional tag copying. M On 04/25/2016 10:20 PM, Jingyi Sun wrote: > Hello experts, > > I have a question regarding using both OFDM packe

Re: [Discuss-gnuradio] OFDM Constellation Issue

You have windows enabled in the FFTs. Switch to rectangular windows for OFDM (you can check out the OFDM examples). M On 04/16/2016 02:53 PM, Abhinav Jadon wrote: > Hi, > I made two flowgraphs. > 1st flowgraph : Source -> BPSK modulation -> Constellation Sink > 2nd flowgraph : Source -> BPSK modu

Re: [Discuss-gnuradio] OFDM tx rx error

o, and any insights into this would be appreciated!! > > > Thanks, > Jenny > > -- > > *From*: Martin Braun > *Subject*:Re: [Discuss-gnuradio] OFDM transmi

Re: [Discuss-gnuradio] OFDM benchmark optimal parameter

Marcus, many thanks I will do it. On Mon, Mar 21, 2016 at 11:01 AM, Marcus Müller wrote: > I'd encourage you to either fix the Bit Error Rate block or write > something that does your job. In fact, the unmodified ofdm_loopback example > doesn't work as BER test, because all packets are identical

Re: [Discuss-gnuradio] OFDM benchmark optimal parameter

I'd encourage you to either fix the Bit Error Rate block or write something that does your job. In fact, the unmodified ofdm_loopback example doesn't work as BER test, because all packets are identical, and if a packet has errors, the OFDM receiver will drop it, so you'd never see an error. Open r

Re: [Discuss-gnuradio] OFDM benchmark optimal parameter

Marcus, I look at ofdm_loopback.grc example, I made the same scenario but I had problem with Error Rate block I got error rate around 4 to 5, as my knowledge that is not right I think should be between 0 to 1. If there is a transceiver example with measure bit error rate that will be helpful for me

Re: [Discuss-gnuradio] OFDM benchmark optimal parameter

Note that the benchmark_rx/_tx example is really a bit old, and I always try to steer people away from it towards the newer OFDM examples that are far more flexible and behave a lot more like a real system would. Have a look at the ofdm_loopback.grc example; you can replace the (channelmodel->thro

Re: [Discuss-gnuradio] OFDM benchmark optimal parameter

many thanks On Mon, Mar 21, 2016 at 10:31 AM, Marcus Müller wrote: > Diyar, > > > I look at tx benchmark help I could not find rates but there is packet > size and megabytes to transmit. > > benchmark_tx --help should help you. > You set the bandwidth, which sets the sampling rate; together with

Re: [Discuss-gnuradio] OFDM benchmark optimal parameter

Diyar, > I look at tx benchmark help I could not find rates but there is packet size and megabytes to transmit. benchmark_tx --help should help you. You set the bandwidth, which sets the sampling rate; together with the occupied tones number related to the FFT length, you get a symbol rate. Toget

Re: [Discuss-gnuradio] OFDM benchmark optimal parameter

Dear Marcus, Thank you very much indeed for fast replying. I look at tx benchmark help I could not find rates but there is packet size and megabytes to transmit. so that, which one do you mean packet size or megabytes? it is okay to use USRP B210 for transmitting and receiving by using to benchmark

Re: [Discuss-gnuradio] OFDM benchmark optimal parameter

Diyar, with the benchmark_ scripts, you **set** the rates, and you can only observe how many packets were successfully transmitted. The rest is really very basic math. Best regards, Marcus On 21.03.2016 10:50, Diyar Muhammed wrote: > Dear SangHyuk, > I would like to know how to measure Throughpu

Re: [Discuss-gnuradio] OFDM benchmark optimal parameter

Dear SangHyuk, I would like to know how to measure Throughput and BER by using benchmark tx and rx? could you show or explain with real example as you used. in advance thanks. On Mon, Mar 21, 2016 at 8:09 AM, Marcus Müller wrote: > Hi, > > On 21.03.2016 01:37, SangHyuk Kim wrote: > > I want to k

Re: [Discuss-gnuradio] OFDM benchmark optimal parameter

Hi, On 21.03.2016 01:37, SangHyuk Kim wrote: > I want to know other user's performance (avg performance). Yes, but what is "user's performance"? Is it more important to have higher throughput, or lower error rates? What about robustness? I mean, the OFDM rx_benchmark is a really static example. Y

Re: [Discuss-gnuradio] OFDM benchmark optimal parameter

Hi, I want to know other user's performance (avg performance). When I operate ./benchmark_tx.py -f 1.5G -m qpsk -W 250 --fft-length=256 --tx-gain=31.5, it results up to 60Mbps. (USRP N210, CBX 40MHz, ANT500) I empirically got fine parameters and generally (small fft length, high bandwidth, h

Re: [Discuss-gnuradio] OFDM benchmark optimal parameter

Trial and error. It depends on your environment, what you want to test, and what you want to achieve. Best regards, Marcus On 19.03.2016 14:15, SangHyoeg Kim wrote: > Hi, I am using ofdm/benchmark example with USRP N210 and CBX 40Mhz > daughterboard. > > I tried to know optimal parameter(bandwid

Re: [Discuss-gnuradio] OFDM Training Sequence

Mateusz, the sync words are both for the Schmidl & Cox synchronization. Also, they're defined in the frequency domain, so you won't see the 'two identical parts here'. Rather, you skip every 2nd carrier. Cheers, Martin On 03/17/2016 04:47 AM, Mateusz wrote: > Hey, I do my Bachelor Thesis on OFDM

Re: [Discuss-gnuradio] OFDM with noise - lost packets

I need to check the loopback flowgraph you mentioned, but the header detection should work down to very low Eb/N0 values. However, you mention a noise amplitude of 1.5. IIRC, that would yield an SNR below 0 dB, not 13 dB as you mention. Cheers, Martin On 19.12.2015 17:41, Mateusz wrote: > Hello

Re: [Discuss-gnuradio] ofdm demod could not demodulate

Hi Gnoob16, it would be interesting to see your actual OFDM demodulator flowgraph, as well as the spectrum you see on the Qt frequency sink in your picture. However, the fact that the OFDM demod doesn't output anything usually simply means that it doesn't detect any packets coming in; are you sure

Re: [Discuss-gnuradio] ofdm plateau_detector_fb_impl//ofdm_sync_sc_cfb_impl

On 31.08.2015 07:15, zs wrote: >According to the step 2 and step3, we copy the > d_items_per_symbol * d_itemsize bytes after (in + d_gi * d_itemsize) to > the output.In the example, cdef+abcdef,the d_gi is 4. (in + d_gi * > d_itemsize) will correspond to the c.Then output d_items_per_sy

Re: [Discuss-gnuradio] ofdm mod error

- Oorspronkelijk bericht - Van: "Marcus Müller" Aan: discuss-gnuradio@gnu.org Verzonden: Maandag 24 augustus 2015 16:59:13 Onderwerp: Re: [Discuss-gnuradio] ofdm mod error The point is that what you're seeing is clearly a Python telling you that it can't find the crc

Re: [Discuss-gnuradio] ofdm mod error

The point is that what you're seeing is clearly a Python telling you that it can't find the crc32_bb module nor the constellation_psk object where they should be, on a proper installation of GNU Radio. This is not a problem of these examples, but of your installation; as Martin hinted, we need to s

Re: [Discuss-gnuradio] ofdm mod error

I'm using ZedBoard by ADI as my dev board and this is their instructions for installing everything... http://wiki.analog.com/resources/tools-software/linux-software/zynq_images I did everything in here... It seems everything about the OFDM blocks have similar problem... -- Posted via http://w

Re: [Discuss-gnuradio] ofdm mod error

Patrcia, this looks more like you don't have GNU Radio properly installed -- these examples will work fine with a full installation of GNU Radio. Cheers, Martin On 19.08.2015 23:43, Patrcia Wonder wrote: > Hi! I think I'm using the latest OFDM blocks. I then tried using the > ofdm_loopback.grc

Re: [Discuss-gnuradio] ofdm mod error

i've noticed that the digital_swig causes some error for both... looking at it, there is nothing inside the digital_swig.py file... is that ok? -- Posted via http://www.ruby-forum.com/. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https:

Re: [Discuss-gnuradio] ofdm mod error

Hi! I think I'm using the latest OFDM blocks. I then tried using the ofdm_loopback.grc and an error occured that is similar to the first one... "Showing: "/home/analog/Documents/ofdm_loopback.grc" Generating: "/home/analog/Documents/ofdm_loopback_example.py" Executing: "/home/analog/Documents

Re: [Discuss-gnuradio] ofdm mod error

Patrcia, try the new OFDM blocks. I suggest starting with the example ofdm_loopback.grc and working from there to see how things work, Cheers, Martin On 17.08.2015 22:39, Patrcia Wonder wrote: > Hi! I'm using gnuradio on ZedBoard and was trying a simple OFDM Mod > system just like in this video

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

On 22.07.2015 16:49, Jose Perez wrote: > Thanks again Marcus. > > Now I am using the "Head" block... I don't know which number I have to put > in "Num Items" to get out my file with no repeated information. > I can understand this number to a Sin/Cosine function or a random source > that I can li

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Jose, If you set your file source to "repeat" it will produce an infinite amount of samples, just like a sine would. If you know you want to produce 10,000 packets (and see how many are received), you only need to 96*10,000 samples. Hence, you'll use the head block after the file source and set

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Jose, If you set your file source to "repeat" it will produce an infinite amount of samples, just like a sine would. If you know you want to produce 10,000 packets (and see how many are received), you only need to 96*10,000 samples. Hence, you'll use the head block after the file source and set

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Thanks again Marcus. Now I am using the "Head" block... I don't know which number I have to put in "Num Items" to get out my file with no repeated information. I can understand this number to a Sin/Cosine function or a random source that I can limit how many samples I want ... but for a file I do

Re: [Discuss-gnuradio] OFDM channel Estimation Block

Hiii I did following : build% make build% make test gr-digital% gr-modtool makexml ofdm_chanestMMSE_vcvc build% make install everything seemed successful but WHEN opening GRC one block pop ups with : " Cannot import gnuradio. Is the python path environment variable set correctly? All OS:

Re: [Discuss-gnuradio] OFDM channel Estimation Block

Probably you're in gnuradio/gr-digital instead of gnuradio/build. Best regards, Marcus Am 20. Juli 2015 12:12:20 MESZ, schrieb monika bansal : >Hiii > >The previous problem is solved. Now after > >gr-digital % make -j4 > >It is saying : >make: *** No targets specified and no makefile found. Sto

Re: [Discuss-gnuradio] OFDM channel Estimation Block

Hiii The previous problem is solved. Now after gr-digital % make -j4 It is saying : make: *** No targets specified and no makefile found. Stop. But Configuring and Generating is done. What should i do ? On Mon, Jul 20, 2015 at 3:21 PM, Marcus Müller wrote: > Monika, > > obviously, there

Re: [Discuss-gnuradio] OFDM channel Estimation Block

Monika, obviously, there's a mistake in gr-digital/lib/CMakeLists.txt, line 189. A little more trying to solve this yourself might probably help you find the typo; we can't tell you what you've changed, so we can't help you :) Best regards, Marcus On 20.07.2015 11:29, monika bansal wrote: Hi

Re: [Discuss-gnuradio] OFDM channel Estimation Block

Hii After the command : gnuradio % cmake .. Configuring for all other blocks except gr-digital is completed. I am posting the output for gr-digital only : -- Configuring gr-digital support... -- Dependency Boost_FOUND = 1 -- Dependency ENABLE_VOLK = ON -- Dependency ENABLE_GNURADIO_RUNTIME

Re: [Discuss-gnuradio] OFDM channel Estimation Block

Hi Monika, In-Tree components (like gr-digital) are meant to be built within the whole GNU Radio tree, so you don't make a "build/" directory under gr-digital, but under gnuradio: gr-digital % cd .. gnuradio % mkdir build gnuradio % cd build gnuradio % cmake .. gr-digital % make -j4 this wil

Re: [Discuss-gnuradio] OFDM channel Estimation Block

Hii After the following command : gr-digital % gr_modtool add -t general ofdm_chanestMMSE_vcvc and editing the files: include/.h , lib/.h , lib/.cc and python/digital/qa_ofdm_chanest_vcvc.py I run the command gr-digital % mkdir build gr-digital % cmake ../ It giving the following output : -

Re: [Discuss-gnuradio] OFDM channel Estimation Block

yes... i will. On Fri, Jul 17, 2015 at 9:48 PM, Martin Braun wrote: > Monika, > > please make sure you've gone through the tutorials at > http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorials, to > make sure we're speaking the same terminology and all the basics are clear. > > Chee

Re: [Discuss-gnuradio] OFDM channel Estimation Block

Monika, please make sure you've gone through the tutorials at http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorials, to make sure we're speaking the same terminology and all the basics are clear. Cheers, M On 17.07.2015 06:20, monika bansal wrote: > Ok... Thanks :) > > On Fri, Jul

Re: [Discuss-gnuradio] OFDM channel Estimation Block

Ok... Thanks :) On Fri, Jul 17, 2015 at 6:47 PM, Marcus Müller wrote: > You can of course add that later on, but don't forget to change both your > include/blockname.h, your lib/blockname_impl.h and your > lib/blockname_impl.cc. If you want to work with GRC, remember to edit the > .xml in grc/,

Re: [Discuss-gnuradio] OFDM channel Estimation Block

You can of course add that later on, but don't forget to change both your include/blockname.h, your lib/blockname_impl.h and your lib/blockname_impl.cc. If you want to work with GRC, remember to edit the .xml in grc/, too! Best regards, Marcus PS: gr_modtool doesn't do anything magical; it re

Re: [Discuss-gnuradio] OFDM channel Estimation Block

Hii One more doubt... As the gr-digital / include/ ofdm_chest_vcvc.h file have the argument list given as static sptr make( const std::vector &sync_symbol1, const std::vector &sync_symbol2, int n_data_symbols, int eq_noise_red_len=0, int max_carr_offset=-1,

Re: [Discuss-gnuradio] OFDM channel Estimation Block

Hi Monika, absolutely the same method: cd gr-exisitingmodule gr_modtool add Note that this can only work with modules that follow gr_modtool's conventions (i.e. practically only with modules generated with gr_modtool in the first place) Best regards, Marcus On 17.07.2015 13:01, monika bans

Re: [Discuss-gnuradio] OFDM channel Estimation Block

Hii I understood how to create new module and block within this new module using gr-modtool from http://gnuradio.org/redmine/projects/gnuradio/wiki/OutOfTreeModules. I want to add new block in the existing module. How can i do that ? ___ Discuss-gnuradio

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

As I mentioned, use the "head" block. BR, Marcus On 16.07.2015 14:33, Jose Perez wrote: Marcus and Martin, you are helping me to much! Sorry for this guys. I just have this forum to ask because my partners here don't know nothing about GNU Radio. So, I have the number of packets that I received

Re: [Discuss-gnuradio] OFDM channel Estimation Block

On 15.07.2015 21:09, monika bansal wrote: > In the OFDM Channel estimation block, ML estimation has been used. I > want to do MMSE estimation. How should i proceed? > Should i make new module for this or I can add new block in gr-digital? > For MMSE estimator i will need noise variance as well. How

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Marcus and Martin, you are helping me to much! Sorry for this guys. I just have this forum to ask because my partners here don't know nothing about GNU Radio. So, I have the number of packets that I received but how I know how many packets my original file have? (I have: packet_len Value: 96 and m

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

On 15.07.2015 07:23, Jose Perez wrote: > Hi Marcus! > > Yes, Percentage of successful packets would be great for me. But I don't > have idea how blocks I need use in the flowgraph to obtain a number for > this. Run the ofdm_loopback example, and you'll see the receiver block outputs a sequence nu

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Well, that depends, but couldn't you simply save the successfully decoded packets to a file (assuming that no broken packages pass the checksums) and divide that file's size by the payload size of a packet? You'd limit the amount of payload being sent using the good ol' head block. Best regards

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Hi Marcus! Yes, Percentage of successful packets would be great for me. But I don't have idea how blocks I need use in the flowgraph to obtain a number for this. -- View this message in context: http://gnuradio.4.n7.nabble.com/OFDM-example-from-gr-digital-with-UHD-tp54446p54816.html Sent from

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Kind of what Martin hinted at: Percentage of successful packets? Net throughput? On 15.07.2015 02:10, Jose Perez wrote: Ok, Martin. But do you have any suggest to measure how good is the transmission/reception? Thaks. Cheers, José -- View this message in context: http://gnuradio.4.n7.nabble

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Ok, Martin. But do you have any suggest to measure how good is the transmission/reception? Thaks. Cheers, José -- View this message in context: http://gnuradio.4.n7.nabble.com/OFDM-example-from-gr-digital-with-UHD-tp54446p54790.html Sent from the GnuRadio mailing list archive at Nabble.com. _

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

On 13.07.2015 17:49, Jose Perez wrote: > Another question... to use the block "Error Rate" to calculate the > BER of the system, I just need put the File Source block in the > Reference in Error Rate block and the output of Repack Bits block on > RX side? That won't be as helpful as you might thin

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Thanks for all, Martin and Marcus! I changed the Random Source block to a File Source block and put a File Sink block on the receiver side ... It is working well ;) (I am transmitting a .txt file) Another question... to use the block "Error Rate" to calculate the BER of the system, I just need p

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

On 30.06.2015 12:12, Jose Perez wrote: > > So ... Is it possible to see the Constellation points like QPSK in this > flowgraph? > Sorry for so many questions! On TX, you can plot the complex symbols before they go into the carrier allocator. On the receive side, you can do the same after the carr

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Jose, we're talking about this flow graph, right? http://gnuradio.4.n7.nabble.com/file/n54534/ofdm_tx.png In this flow graph, you're trying to find the individual symbols in time domain; that's not possible, they only exist clearly distinguishable in frequency. That is why there is an DFT (in thi

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

So ... Is it possible to see the Constellation points like QPSK in this flowgraph? Sorry for so many questions! Thanks Martin! -- View this message in context: http://gnuradio.4.n7.nabble.com/OFDM-example-from-gr-digital-with-UHD-tp54446p54537.html Sent from the GnuRadio mailing list archive

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

On 30.06.2015 11:06, Jose Perez wrote: > I am plotting the signal after the Multiply Const Block ... the signal that I > will transmitt with USRP. > Isn't correct? > If what you want to plot is your constellation, then no, it's not. This is all modulated, pulse shaped and all. Cheers, M __

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

I am plotting the signal after the Multiply Const Block ... the signal that I will transmitt with USRP. Isn't correct? -- View this message in context: http://gnuradio.4.n7.nabble.com/OFDM-example-from-gr-digital-with-UHD-tp54446p5453

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

On 30.06.2015 10:41, Jose Perez wrote: > Hi Marcus, > > Thanks so much for the answer. But like in the screenshots of Gabriele, the > blocks OFDM Transmitter e OFDM Receiver are off. And I can't visualize four > symbols (QPSK) or 2 symbols (BPSK) in the output of QT Constellation just a > big one

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Hi Marcus, Thanks so much for the answer. But like in the screenshots of Gabriele, the blocks OFDM Transmitter e OFDM Receiver are off. And I can't visualize four symbols (QPSK) or 2 symbols (BPSK) in the output of QT Constellation just a big one (see the screenshot), is this correct? Thanks agai

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Hi Jose, > And I have another question (if Marcus can help) ... what is the modulation > in this example (QPSK, QAM)? You can set that yourself in the OFDM Transmitter Block, separately for header and payload. > Sorry for my bad english Your English is really fine, don't worry. If we don't underst

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Hi, Gabriele, do you have news about this? I am trying to do the same. And I have another question (if Marcus can help) ... what is the modulation in this example (QPSK, QAM)? Sorry for my bad english Thanks -- View this message in context: http://gnuradio.4.n7.nabble.com/OFDM-example-fr

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Hi Gabriele, if there is no output, chances are the receiver side packet detector doesn't see any valid packets. Make sure tx and rx parameters match, and adjust the RX gain. Make sure no under/overflows happen. There's quite a lot of things that can go wrong in a real-world transceiver, but these

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Thanks Marcus and Martin. I finally increased the sample rate up to 1 Msps and decreased the amplitude multiplier. Now I can see a clear ofdm spectrum with no distortion at all. Did some of you tried file transmission from one end to the other? I did it for GMSK before. Now when it comes ofdm and

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

On 25.06.2015 06:07, Marcus Müller wrote: > Hi Gabriele, > > have you tried adding more gain on the TX side? ...or less gain? > Also, you will need to increase sampling rate. Right now, you're using > 100kHz, which is 1/1000 of the master clock rate of the N200. If I'm not > mistaken, the maximu

Re: [Discuss-gnuradio] OFDM example from gr-digital with UHD

Hi Gabriele, have you tried adding more gain on the TX side? Also, you will need to increase sampling rate. Right now, you're using 100kHz, which is 1/1000 of the master clock rate of the N200. If I'm not mistaken, the maximum decimation for the N200 is 512, and hence the minimum rate would be 100

Re: [Discuss-gnuradio] ofdm frequency offset

On 24.06.2015 01:48, zs wrote: > > Dear Marcus Müller: > > Do you know which is the synchronization algorithm used in the old > version of ofdm example?Where is the source code of the old ofdm version > in gnuradio?Thanks. It's a very similar implementation to the 'new' versions. In stock GNU Ra

Re: [Discuss-gnuradio] ofdm frequency offset

Dear Marcus Müller: Actually my problem is: y=useful information+x*h(channel)*cfo(carrier offset due to the local oscillator between the interference and the radar)+noise. I want to turn y to new_y=useful information+noise. So I need know the channel(h) a

Re: [Discuss-gnuradio] ofdm frequency offset

Dear Marcus Müller: Thank you so much.So kindly of you.Thanks.I will read the papers you mentioned. Best regards, zs At 2015-06-24 17:08:16, "Marcus Müller" wrote: Hi zs, this reminds me very much of OFDM radar technologies, as your problem boils down to finding a good estimator for the

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