Hi, I want to know if ever any work was done on Spread Spectrum (DSSS) in Gnuradio?
on 2009-01-28 17:32
on 2009-01-30 01:37
On Wed, Jan 28, 2009 at 9:31 AM, Mir A. <email@example.com> wrote: > I want to know if ever any work was done on Spread Spectrum (DSSS) in > Gnuradio? Yes. I have done both host code and FPGA code implementation of DSSS with the USRP1 and in progress with USRP2. These will eventually make into the public GNU Radio tree, but it might be some time before that happens. Johnathan
on 2009-01-30 04:21
> These will eventually make into the public GNU Radio tree, but it > might be some time before that happens. Are there CGRAN projects?
on 2009-02-04 00:29
Johnathan, So your DSSS code is not yet public? How did you manage waveform synchronization among multiple USRPs? Thanks. Mark
on 2009-02-04 02:46
On Tue, Feb 3, 2009 at 4:28 PM, Mark K. <firstname.lastname@example.org> 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
on 2009-02-24 06:26
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 C. <
on 2009-02-24 18:24
On Mon, Feb 23, 2009 at 8:25 PM, Mir A. <email@example.com> wrote: > 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. There is plenty of information available via Google. An excellent reference book is: "Fundamentals of Global Positioning System Receivers: A Software Approach" Wiley Series in Microwave and Optical Engineering James Bao-Yen Tsui, 2004 Johnathan
on 2009-07-15 21:07
Hi Johnathan, I have a few question regarding implementation. The book that you referred earlier was of great help. Thanks. I am sure this won't take a lot of your time and I would be really glad and thankful to you if you answer them. In the transmitter the data and the PN code is ex-or and then modulated and transmitted. So basically this is a BPSK transmission. At the receiver the received signal is first multiplied by the PN code in order to strip it free of PN code and this happens at the E/P/L correlation and Costas Loop block. Being a BPSK signal this is correct. 1. My question is can I just use the upsampler and multiply the upsampled sequence with the received signal samples? 2. Where will the AGC and the RRC filter go in this arrangement? Any help would be appreciated. Thanks. Ali On Tue, Feb 24, 2009 at 11:23 AM, Johnathan C. <
on 2009-07-18 03:03
Thanks, I will try this out.
on 2009-10-04 04:42
Hi Johnathan, Is your code public yet?