[Discuss-gnuradio] OFDM frame detection

Hello, In the OFDM examples in gr-digital, for the packet detection blocks (Schmidt and Cox, Freq Mod and Delay), how to better choose the parameters  for different FFT lengths. the problem I have to figure out that manually.   Thank you.  ___

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

Hi Alex, you may want to take a look at the OOT module gr-cdma ( https://github.com/anastas/gr-cdma). This system implements a two-channel system with one of the orthogonal channels being continuously transmitting pilots, while the other carries data (in a synchronous/asynchronous way). The Rx is

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

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

I'm playing around with an OFDM transmit/receive chain. I've noticed that if I get underruns at a high enough rate, it becomes a bursty system and the receiver is unable to lock in and no longer demodulates the symbols. Would it be possible to generate continuous pilot tones or send OFDM frames

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 dont 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

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

Hi,   I'm working with grc and a LimeSDR board and saw that there is the "OFDM Mod" Block available that I thought I could use to generate a broadband signal that is similar to a channel in LTE. In detail I want to generate a signal with a known bandwidth like 5MHz  and analyze how the LimeSDR

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

[Discuss-gnuradio] OFDM

Hello,I am trying to change the OFDM_tx_rx payload modulation by a custom 64kQAM,I implemented the block in several ways, it works fine but I had issues using it with OFDM_tx_rx:/*1- sync:taking a short item and produce a complex

[Discuss-gnuradio] OFDM / softcast / rate distortion theory (was:Re: OFDM_TX_RX)

As said, I doubt that omitting channel coding is a good idea, but OK, you do the math. In any case, when you really don't want channel coding and symbol mapping, and none of the header structure the OFDM blocks offer, you'll simply be best off writing your own OFDM transmitter – no big deal,

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

[Discuss-gnuradio] OFDM cyclic prefix

Hi Team, I am trying to make own cyclic prefix block in C++ in GNU Radio(removing roll-off part and keeping all other parameters same). After connecting my cyclic_prefix block to the already present FFT block in tx_ofdm.grc, i am getting the following error: Executing: /usr/bin/python2 -u

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

[Discuss-gnuradio] OFDM Frequency Spacing

Hello GNURadio Users, Is it possible to specify the frequency spacing of the carriers in the OFDM Transmitter Block or Carrier Allocator block? My assumption is the carrier spacing is calculated from the sampling rate and the FFT length (e.g, if sampling rate is 640k and fft length is 64, is the

[Discuss-gnuradio] OFDM TX original example - output broken

Hey All! I'm fighting a problem with the original GNU Radio OFDM TX example from https://github.com/gnuradio/gnuradio/blob/master/gr-digital/examples/ofdm/tx_ofdm.grc Nothing is changed, except adding two File Sinks writing the data to two text files. One File Sink is added at the random

[Discuss-gnuradio] OFDM Carrier Allocator

Hello, I have trouble assigning parameters to sync words in OFDM Carrier allocator block in gnu radio. Does anyone has an example to share. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

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

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

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

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

[Discuss-gnuradio] OFDM TX/RX

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 so, I use the following configuration : samp_rate = 1.92 MHz, fft

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

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

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

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)

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))) {

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

[Discuss-gnuradio] OFDM channel tap questions

Hi all, I run the example found in the ~/prefix/share/gnuradio/examples/digital/ofdm/rx_ofdm.grc. The ofdm signals can be decoded correctly. But I don't understand the channel taps. The channel taps are shown to be Key: ofdm_sync_chan_taps Value: #[(0,0) (0,0) (0,0) (0,0) (0,0) (0,0)

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

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

[Discuss-gnuradio] OFDM Preamble

Hi, Could anyone please help me to set the input parameters in "OFDM Insert Preamble" OOT in GNURadio? It has 2 parameters FFT Length, and Preamble. Where should it be used in the tx_ofdm.grc example. Thank you for the help in advance. Regards, Adhitha Dias

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

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

Hi everyone, I've been working on a coded-OFDM system (looks similar to the standard OFDM flowgraphs) and have come to the stage where I am trying to improve channel estimation by implementing LS, STA and comb pilot interpolation methods similar to gr-ieee802.11. If I follow the default technique

[Discuss-gnuradio] Ofdm rx_time and packet error rate

Hi All, First of all: I'm a newbee I'm into the example of gr-digital: rx_ofdm.grc and tx_ofdm.gr. I have 2 Questions: 1. My goal is to check the time between 2 recieved packets. I realized that the TAG_DEBUG-Block outputs some rx_Time. Offset: 1035 Source: n/a Key: rx_time Value: {2523

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

[Discuss-gnuradio] OFDM implementation for high data rates

Hi, For OFDM transmitter and receiver, I was using benchmark_tx/rx implementations. However, I am wondering what is the best publicly available OFDM implementation for relatively high bandwidths (10s of MHz) and data rates (10s of Mbps)? Best, Sinan

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,

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

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,

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

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

Please forgive me as I am new to SDRs and DSP. I am interested in development of a radio link using two B210s and GR-IEEE802-11. However, I would like for this link to operate at any frequency. I am interested in a robust waveform with minimum of 11MBPS throughput, which is why I am interested

[Discuss-gnuradio] OFDM Receiver

Hi, I am referring the built in example of gnuradio companion ( rx_ofdm.grc). In which I replace random source with usrp source. on Transmetter side I am sending some bits and in receiver flow graph (rx_ofdm ) I am facing problem where I have to attach file sink to get these bits. I attached

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

[Discuss-gnuradio] OFDM receiver

How can I receive bits using file sink in ofdm receiver. where I have to connect file sink in flow graph of ofdm receiver? either bits repack block output can give bits? ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org

[Discuss-gnuradio] OFDM channel etimation

Hi, I want to estimate the channel (h) using OFDM. I am using rx_OFDM.grc flow graph for OFDM implementation. According to my knowledge, I can find channel from the output of OFDM channel estimation block. The channel is present on tags. But how can I extract channel form these tags. If I connect

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

[Discuss-gnuradio] OFDM channel estimation

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 look a bit strange to me. Can anybody explain why there

[Discuss-gnuradio] OFDM sync word generator

Hi! I was wondering if there is any code block available to generate suitable sync words for OFDM transceivers. I want to use 512, 1024 and 2048 as FFT length for OFDM. Any help is much appreciated. == Thanks and Regards, Suman Bhunia PhD candidate in CSE University of

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

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

[Discuss-gnuradio] OFDM IFFT calculate

Hi all, The file, /gr-fft/lib/fft_vcc_fftw.cc(http://goo.gl/X8WNPh), changes domain from frequency to time using IFFT(Inverse-Fast-Fourier-Transform). It takes parallel subcarriers in frequency-domain (it is defined 'in' in the file) and converts it into time-domain(it is defined 'out'). I can

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

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

[Discuss-gnuradio] OFDM Constellation Issue

Hi, I made two flowgraphs. 1st flowgraph : Source -> BPSK modulation -> Constellation Sink 2nd flowgraph : Source -> BPSK modulation -> IFFT -> FFT -> Constellation Sink The source is configured such that if only transmits 1s. Therefore one would expect the constellation plot to have one dot on

Re: [Discuss-gnuradio] OFDM tx rx error

would be appreciated!! > > > Thanks, > Jenny > > -- > > *From*: Martin Braun > *Subject*:Re: [Discuss-gnuradio] OFDM transmitter receiver > *Date*:

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,

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

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

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

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

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.

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

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

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

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.

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,

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

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

[Discuss-gnuradio] OFDM tx rx error

list so I'm assuming it didn't go through the first time. -- *From*: Martin Braun *Subject*: Re: [Discuss-gnuradio] OFDM transmitter receiver *Date*: Tue, 26 Aug 2014 11:10:53 +0200 *User-agent*: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gec

[Discuss-gnuradio] OFDM tx rx error

Braun *Subject*: Re: [Discuss-gnuradio] OFDM transmitter receiver *Date*: Tue, 26 Aug 2014 11:10:53 +0200 *User-agent*: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 -- Try and not kill the context in a mailing list thread; these are also a

[Discuss-gnuradio] OFDM benchmark optimal parameter

Hi, I am using ofdm/benchmark example with USRP N210 and CBX 40Mhz daughterboard. I tried to know optimal parameter(bandwidth, fft length, occupied tones, packet size) for maximum throughput and minimum error rates. How can I reach maximum throughput by adjusting parameter or modifying code

[Discuss-gnuradio] OFDM Training Sequence

Hey, I do my Bachelor Thesis on OFDM using GnuRadio. I am using the joint system created from tx_ofdm and rx_ofdm examples. In simulation I try to use a bigger fft. So far I have managed to send and receive for fft_len=128 and fft_len=256, BPSK modulation. I ask to help me understand the

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: >

[Discuss-gnuradio] OFDM with noise - lost packets

Hello, I have been evaluating the OFDM examples (at the beginning of my Bachelor Thesis) In ofdm_rx I have added noise source and file sinks to plot BER(SNR) in matlab. I added a Tag Debug on the output. The result is disappointing, I observe plenty of lost packets already at the SNR of about

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

[Discuss-gnuradio] ofdm demod could not demodulate

hi this is my ofdm transmitter... the thing here is that the ofdm signal could not get demodulated at all... the qt frequency sink displays nothing when connected after the ofdm demodulator... im using zedboard with the adi fmcomms...

[Discuss-gnuradio] ofdm plateau_detector_fb_impl//ofdm_sync_sc_cfb_impl

Hi all, I have a question on the synchronization of ofdm example,namely the sch source code. The plateau_detector_fb_impl.cc can find the plateau,and then header_payload_demux_impl can find the head data. STEP 1: plateau_detector_fb_impl find the plateau.

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

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

Re: [Discuss-gnuradio] ofdm mod error

- Oorspronkelijk bericht - Van: Marcus Müller marcus.muel...@ettus.com 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 crc32_bb

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

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

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:

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

[Discuss-gnuradio] ofdm mod error

Hi! I'm using gnuradio on ZedBoard and was trying a simple OFDM Mod system just like in this video https://www.youtube.com/watch?v=LZDWfnrxo6c the flowgraph just looks like this... random sourceshort to floatofdm modthrottlewx gui fft sink and this comes up... Generating:

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

[Discuss-gnuradio] OFDM and FEC combined

I am working with the OFDM and FEC blocks combined in the same flowgraph, but this configuration led to some issues and I am not being able to sort this out. I am using the OFDM Transmitter and Receiver Hier Blocks and FEC Encoder and Decoder, but I already used FEC Extended Decoder/Encoder with

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 limit how

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 don't

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

yes... i will. On Fri, Jul 17, 2015 at 9:48 PM, Martin Braun martin.br...@ettus.com 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

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

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::vectorgr_complex sync_symbol1, const std::vectorgr_complex sync_symbol2, int n_data_symbols, int eq_noise_red_len=0, int

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: [Discuss-gnuradio] OFDM channel Estimation Block

Ok... Thanks :) On Fri, Jul 17, 2015 at 6:47 PM, Marcus Müller marcus.muel...@ettus.com 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

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 ? ___

  1   2   3   4   5   6   >