I ask how can i add a block in grc witch exist in gnuradio for example
the cyclic prefix exist in gnuradio but in grc it’s combined in OFDM
block and i want to use it as a block in grc , i know only that i  have
to configure an xml file of this block and rebuild gnuradio ( i’m using
gnuradio 3.2rc)
thanks
Take a look at this guide:
http://gnuradio.org/trac/wiki/GNURadioCompanion#CreatingtheXMLBlockDefinition
http://gnuradio.org/trac/wiki/GNURadioCompanion#InstallingtheXMLBlockDefinition
- create the xml file
- copy it into ~/.grc_gnuradio/
- run grc
-Josh