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

[Johnathan Corgan]

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