Re: [Discuss-gnuradio] OFDM Updates

[CHIN-YA HUANG]

Hi Tom,

Would you mind release your modified code for me as reference first? Thanks

Chin-Ya
----- Original Message -----
From: Tom Rondeau <address@hidden>
Date: Wednesday, March 26, 2008 9:50 am
Subject: Re: [Discuss-gnuradio] OFDM Updates
To: CHIN-YA HUANG <address@hidden>
Cc: address@hidden

> CHIN-YA HUANG wrote:
> > Hello Tom,
> >
> > Based on your information below I know the problem will be receiver. 
> However, if I want to solve the receiver's problem. Where is the 
> starting point you suggestion? From the gnu-radio core part?
> >
> >
> > Chin-Ya
> >   
> 
> This problem will be fixed once I get time to merge my current branch, 
> 
> which will be in a few days, hopefully.
> 
> Tom
> 
> 
> > From:       Tom Rondeau
> > Subject:    [Discuss-gnuradio] OFDM Updates
> > Date:       Thu, 07 Feb 2008 14:09:58 +0000
> > User-agent:         Thunderbird 2.0.0.9 (Windows/20071031)
> > For anyone working with the OFDM code, my latest check-in to the 
> trunk fixes some of the main issues of transmitting over the air. 
> Using benchmark_ofdm_rx and benchmark_ofdm_tx on different machines, I 
> am now able to successfully capture most packets with any modulation 
> at the appropriate signal level.
> >
> > I say most packets because there is still an issue involved in the 
> receiver where the regenerator signal pops up before the peak detector 
> signal resets it and causes a problem in the packet sampler. To see 
> what I mean, run
> > "benchmark_ofdm.py --log"
> >
> > And look at the output of the regen and peak detector blocks:
> > gr_plot_char.py ofdm_sync_pn-regen_b.dat ofdm_sync_pn-peaks_b.dat
> >
> >
> > This will plot a series of 0's with a few 1's, where the peaks 
> occur. The peak detector sends it out once, and then the regenerator 
> takes over. For every packet, there is one output of the peak 
> detector. If you look, sometimes the peak detector will hit just after 
> a regenerated signal. By this point, it's too late and the 
> ofdm_sampler has already triggered off of the regen signal and ignores 
> the peak.
> >
> > It's a bit of a hassle, but I'll look into it soon. Any help is 
> appreciated, though :)
> >
> > Tom
> >
> >   
>