Constellation mapping

GNU Radio
1

I want to do constellation mapping in pyhton. I have code that does a
gr.packed_to_unpacked_bb and then gr.chunks_to_symbols_bc using a
constellation of:

constellation=array((1+1j,1-1j,-1-1j,-1+1j),Complex)

My understanding is that this is the constellation mapping for QPSK. I
want to do constellation mapping for BPSK and 64-QAM. I don’t have a
lot of GNU radio experience so I’m not really sure how to do this. Is
all I do is change the array (all the possibilities from 4+4j to -4-4j
for 64-QAM and 1+0j to -1+0j for BPSK) and the code will do the rest to
map the data for the other modulation schemes?

Thanks for the help in advance,
Nick

2

On Sun, Mar 04, 2007 at 06:20:07PM -0500, [email protected] wrote:

I want to do constellation mapping in pyhton. I have code that does
a gr.packed_to_unpacked_bb and then gr.chunks_to_symbols_bc using a
constellation of:

constellation=array((1+1j,1-1j,-1-1j,-1+1j),Complex)

Use this:

constellation=(1+1j,1-1j,-1-1j,-1+1j)

My understanding is that this is the constellation mapping for QPSK.
I want to do constellation mapping for BPSK and 64-QAM. I don’t
have a lot of GNU radio experience so I’m not really sure how to do
this. Is all I do is change the array (all the possibilities from
4+4j to -4-4j for 64-QAM and 1+0j to -1+0j for BPSK) and the code
will do the rest to map the data for the other modulation schemes?

Have you looked at the mpsk code that’s in the tree? Most of this
stuff is already in place. I believe that Tom R. is working on
QAM too.

Thanks for the help in advance,
Nick

Eric

3

Have you looked at the mpsk code that’s in the tree? Most of this
stuff is already in place. I believe that Tom R. is working on
QAM too.

Yep, you can already look in python/gnuradio/blksimpl for DBPSK and
DQPSK.
I’m finishing up the tests on the new stuff now and hopefully will get
those
checked in to the trunk by the end of today.

This will include D8PSK and a number of square QAM modulations up to
M=256.
These are currently disabled until the receivers are finished, but the
code
will be there to see how I’m doing it. The modulators have been verified
using our signal analyzer.

Tom