Re: [Discuss-gnuradio] GNURadio OFDM receiver design

[Jens Elsner]

Achilleas,

great. I'll then focus for now on implementing time/frequency
synchronization. Does the decoder support puncturing? Did you publish 
you code already?

Concerning my "jitter" problem: I sampled another DAB source with the
DBSRX daughterboard and implemented a correlation based frequency
synchronization algorithm. That pretty much solved the problem (although
a little jitter is still there). 

Jens

On Sat, May 06, 2006 at 12:51:50PM -0400, Achilleas Anastasopoulos wrote:
> Jens,
> 
> I already have implemented generic blocks for
> 
> - convolutional encoder / Viterbi decoder
> 
> also, with this it is straightforward to implement
> 
> - Differential coding
> 
> Finally, I am currently implementing a generic
> 
> - interleaver/deinterleaver.
> 
> 
> Achilleas
> 
> 
> >Message: 2
> >Date: Sat, 6 May 2006 14:30:52 +0200
> >From: Jens Elsner <address@hidden>
> >Subject: [Discuss-gnuradio] GNURadio OFDM receiver design
> >To: address@hidden
> >Message-ID: <address@hidden>
> >Content-Type: text/plain; charset=us-ascii
> >
> >Hello everybody,
> >
> >I'd like to implement the physical layer of the DAB standard in GNURadio.
> >The resulting code of should be as versatile as possible since the basic
> >basic OFDM concept is the same for a lot of standards.
> >
> >Blocks that should be reusalbe are
> >
> >     - OFDM time and frequency synchronization
> >      -> should be based *only* on cyclic prefix correlation
> >         Performance is worse but standard independend.
> >     - carrier-to-symbol mapping
> >     - frequency (de)interleaver
> >
> >Apart from OFDM:
> >     - matrix time (de)interleaver 
> >     - symbol mapping
> >     - QAM decoder
> >     - Differential coding
> >     - (de)scrambling
> >     - Viterbi decoder / convolutional encoder
> >
> >All these tasks are very common. I'd like to write a general version
> >first and then adapt these blocks through inheritance for DAB.
> >
> >Some of the functionality exists already in the ATSC implementation. But I 
> >feel
> >there should be a general concept about how to integrate these blocks
> >into GNURadio. 
> >
> >So far I'm not familiar with the details of GNURadio. Is someone working
> >in this direction? What could be adapted from other free software
> >projects?
> >
> >Jens
> 
> 
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