Re: [Discuss-gnuradio] Any implementation of Spread Spectrum

[Mir Ali]

Hi Johnathan,

can you suggest me a place where I can find more information about the phase sync and the freq sync methods you used in your work. It will be of great help to me.

Thanks,
Ali.

On Tue, Feb 3, 2009 at 6:45 PM, Johnathan Corgan <address@hidden> wrote:

On Tue, Feb 3, 2009 at 4:28 PM, Mark Kuhr <address@hidden> wrote:

> So your DSSS code is not yet public?  How did you manage waveform
> synchronization among multiple USRPs?

Not sure I understand your question.  My DSSS implementation is a
unidirectional continuous transmitter and separate receiver,
implementing m-sequence based chipping.  The receiver performs code
phase synchronization using early/prompt/late correlation power and
frequency synchronization using a Costas loop on the despread BPSK
signal.

Or perhaps you're asking about multiple, simultaneous
transmitter/receiver pairs.  Right now, this is not optimal, as
m-sequences have poor cross-correlation properties, but I'll
eventually put in Gold code generators.  While this system was
designed with a completely different purpose in mind, one goal I have
is to eventually be able to use the receiver part of the code as a GPS
L1 demodulator.

Johnathan


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-- 
Mir Murtuza Ali
Graduate Student
Center for Wireless Communications
University of Mississippi
University, MS 38677