Tom, in your email exchange with Richard Clarke on 29 Jan 2008, as shown below, it was mentioned that a multi-path channel model might be integrated into GNU Radio library.
I am wondering whether this has happened or not? If not, do you still have code written by Richard's student? If so, would you suggest ways that I can get a copy of the code.
The FTP that Richard set up is not accessible now.
Tue, 29 Jan 2008 23:20:24 +0000
Richard Clarke wrote:
I have had a Summer student doing some work on this (a year
ago now). He implemented a GNU Radio module that can
do Rayleigh channel simulation. He based it on a
particular paper (I'd have to look it up) for the
implementation. He verified the statistical performance of his implementation
against the Matlab Rayleigh channel model and against theory
and found it to be a close match. I'm not entirely convinced of
the delayed multiple path aspects of the
design/implementation but haven't had time to look
into it further. In fact as it stands I believe the
GNU Radio module (at C++ level) only handles a single flat fading
path and doing multiple delayed paths is done at the python module
level and which invokes multiple instances of the Flat fading Rayleigh
C++ GNU Radio module.
I'd welcome another set of eyes and someone more
experienced than I am with GNU Radio to help finish
off this potentially very useful addition to the GNU
Radio code base.
That sounds great; please let us contribute it. We have a basic
channel model in Python that implements an AWGN channel,
but has a filter, which you can set the taps to do
fading. It'd be nice if we could enhance this to
implement a Rayleigh, and even Rician channel (Nakagami, too, for
those of you who really care about this stuff).
Sounds like your student did some version of Jakes' model.
At least, that's where I'd start. I have this in Matlab
from an old class project that I was going to see about
resurrecting, but it'd be great to have it already
implemented in GNU Radio.