Re: [Discuss-gnuradio] WCDMA with USRP

[Jens Elsner]

The standard is ETSI TS 125 213 (Spreading and modulation FDD), 
not 113 as I claimed below.

Jens

On Sat, Jun 10, 2006 at 04:20:10PM +0200, Jens Elsner wrote:
> Dan,
> 
> I sampled an UTRA FDD downlink signal and implemented the widely know
> standard cell search algorithm (see for example
> http://www.umtsworld.com/technology/cell_search.htm). To understand the
> details, you need to download the right document in the standard (ETSI
> TS 125 113, if I remember correctly) which is available at www.etsi.com.
> There are also loads of papers at the IEEE.
> 
> The algorithm:
> 
> 0. Resampling to N*3.84 Mcps, internal oversampling needed to compensate
> for non-ideal sampling, matched filtering
> 1. DFT stage for coarse frequency aquisition using the PSC (synch to
> slot)
> 2. correlation with SSCs to get code group (synch to frame)
> 3. try the 8 different scrambling codes in code group
> 4. fine frequency aquisition using known symbols on the CPICH
> 5. start to despread data channels using CPICH as phase reference 
> 
> Nothing fancy at all. If it works in Matlab, it should work this way in GNU
> Radio, too? Would be a nice project, I guess. I'm not planning on
> implementing the whole show in Matlab (which would be close to
> impossible for me). One purpose was to show that this works with
> the USRP.
> 
> A tricky part is the scrambling code generation, which is described not
> very clearly in the standard. If you have further questions, just ask.
> 
> Jens
> 
> On Sat, Jun 10, 2006 at 09:24:19AM -0400, Dan Veeneman wrote:
> > Hi Jens,
> > 
> > I'm quite interested in WCDMA, and spread spectrum in general, and
> > would certainly be interested in learning more about your algorithm.
> > If you can't send the code, do you have a description of the final
> > algorithm you worked out?  Perhaps even a small section of the
> > code that does the search and despreading?
> > 
> > 
> > Regards,
> > 
> > Dan
> > 
> > 
> > At 04:12 AM 6/10/06, you wrote:
> > >Hello everybody,
> > >
> > >I did some work the last couple of weeks implementing the cell search
> > >algorithm and despreading of basic channels for WCDMA (UMTS) using the USRP
> > >in Matlab.
> > >
> > >Unfortunately I do not have the copyright, so I can't post the code.
> > >
> > >But if anyone is interested in playing with WCDMA in GNU Radio, I'd be
> > >glad to share my insight. For now I'll get back to DAB.
> > >
> > >Jens
> > >
> > >
> > >_______________________________________________
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> > >http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> > 
> 
> 
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