Spectrum sensing in gnuradio-companion

GNU Radio
1

Hello

I am looking for a way to assemble a spectrum sensing in
gnuradio-companion.
Here in gnuradio.blogspot only found information about the file
usrp_spectrum_sense.py, but would like to know how to implement spectrum
sensing (including detection of energy) in gnuradio-companion.

Could anyone help me?

2

I am actually doing something similar for cognitive radio, the best way
to
go about it is to follow the tutorial online for how to write a signal
processing block
http://www.gnu.org/software/gnuradio/doc/howto-write-a-block.html (I do
find a little vague on some parts); you can browse google for a more in
depth guide from University of Notre Dame. Keep in mind the FFT is a
vector
output so you need adjust your sensing block to accept such a stream. If
you understand the underlying concepts of spectrum sensing then you
should
be able to program it. For example, energy detection is based of the
Chi-squared test at a certain threshold of energy. Plenty of white
papers
covering spectrum sensing.

-Jon