# Gr-cdma is ready

**URL:** <https://www.ruby-forum.com/t/gr-cdma-is-ready/239618>\
**Category:** GNU Radio\
**Created:** [March 6, 2014, 11:15pm UTC](https://www.ruby-forum.com/t/gr-cdma-is-ready/239618 "2014-03-06T23:15:46Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\
**Post date:** [March 6, 2014, 11:15pm UTC](https://www.ruby-forum.com/t/gr-cdma-is-ready/239618/1 "2014-03-06T23:15:46Z")

</div>

Dear all,

the OOT module gr-cdma that we have been working on with Zhe F. is now  
ready (also fully documented). You can find it here:

> **[GitHub - anastas/gr-cdma: a cdma physical layer for Gnuradio](https://github.com/anastas/gr-cdma)**
>
> a cdma physical layer for Gnuradio. Contribute to anastas/gr-cdma development by creating an account on GitHub.

An important acknowledgement:

this project grew out of the DARPA SPECTRUM CHALLENGE:  
our team eventually dropped out of the race because of other time  
commitments but I and Zhe decided to finish up the design and make it  
publicly available since DARPA was generous enough to send us USRPs for  
testing etc.

I am looking forward to feedback from the community and to ideas for  
expanding/improving the design.

=======================================  
For the impatient:

1. Download gr-cdma from github

> git clone [GitHub - anastas/gr-cdma: a cdma physical layer for Gnuradio](https://github.com/anastas/gr-cdma.git)

1. Build the package

> mkdir build\_cdma  
> cd build\_cdma  
> cmake -DENABLE\_DOXYGEN=ON …/gr-cdma  
> make  
> sudo make install  
> sudo ldconfig

1. compile hierarchical blocks and play with built in app

> cd gr-cdma/apps  
> gnuradio-companion &  
> In the gnuradio-companion environment  
> – Load the hier block “amp\_var\_est\_hier.grc”, “cdma\_tx\_hier.grc”,  
> “chopper\_correlator1.grc”, “cdma\_rx\_hier.grc” and compile them  
> making sure to reload blocks after each compilation  
> – Load the application “cdma\_txrx.grc” and have fun  
> Experiment with manual acq/tra, auto acq/tra, changing freq and  
> timing  
> offset, SNR, etc  
> – If you have 2 USRPs load the cdma\_tx.grc and cdma\_rx.grc and enjoy  
> real-time  
> CDMA transmission. You can also use the cdma\_tx.grc and cdma\_rx.grc by  
> writting  
> and reading to a fifo (first do \> makefifo /tmp/cdma.fifo)  
> =====================================

best,  
Achilleas

---

<div class="post-metadata">

**Author:** ![Achilleas\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/74df32/32.png) [@Achilleas\_A](https://www.ruby-forum.com/u/Achilleas_A)\
**Post date:** [March 8, 2014, 12:51pm UTC](https://www.ruby-forum.com/t/gr-cdma-is-ready/239618/2 "2014-03-08T12:51:47Z")

</div>

Hi Achillaes,  
can you tell me where the documentation of all the  
blocks  
used in cdma\_tx and cdma\_rx are? I tried the cdma\_trrx.grc and i got a  
menu  
list with options to change freq and timing offset and eb/N0. But i  
wasn’t  
able to transmit and recieve packets or know how changing parameters in  
the  
menu is changing the output. I would like to look into the documentation  
of  
inidvidual blocks to understand better.

On Fri, Mar 7, 2014 at 3:44 AM, Achilleas A.