Forum: GNU Radio Difference between blks and blks2

Hi all,

So I am not too familiar with the history of how GNU-Radio has evolved 
over
the past few years and I am wondering what are the fundamental 
differences
between blks and blks2(old revisions vs new revisions)?

A question I am asking is why did the BBN people who wrote the 802.11b 
code
make their own DPSK mod/demod and did not use the function blocks 
provided
by gnuradio?  Were those blocks simply not available at the time?

Last question.  Has the functionality of teh the DB/QPSK modulations in 
the
blks2 library been tested? I'm in the process of cleaning up the 802.11b
code, and if I can relay on gnu-radio libraries, rather than custom
C++/python code, that would be better.

Thanks,
Colby

On Sun, May 10, 2009 at 1:11 AM, Colby Boyer <csboyer@berkeley.edu> 
wrote:

> So I am not too familiar with the history of how GNU-Radio has evolved over
> the past few years and I am wondering what are the fundamental differences
> between blks and blks2(old revisions vs new revisions)?

The blks2 modules use the new style hierarchical blocks
(gr.hier_block2).  The old style (gr.hier_block) was deprecated (but
still available) in GNU Radio 3.1, and now on the development trunk
and in the 3.2 release, have been removed.

> A question I am asking is why did the BBN people who wrote the 802.11b code
> make their own DPSK mod/demod and did not use the function blocks provided
> by gnuradio?  Were those blocks simply not available at the time?

Possibly, the timeline sounds right.

> Last question.  Has the functionality of teh the DB/QPSK modulations in the
> blks2 library been tested? I'm in the process of cleaning up the 802.11b
> code, and if I can relay on gnu-radio libraries, rather than custom
> C++/python code, that would be better.

Yes, they have been tested and used in a variety of real-world,
commercial applications of GNU Radio.  There were a couple serious
bugs in them that have been fixed as part of 3.2.

Johnathan

I agree with you doug.  After reading through the BBN code, that seems 
like
why they did that.  DBPSK and DQPSK appear to be backward compatible
decoding wise.

I think the reason why you cannot transmit/decode DQPSK packets is that 
the
entire packet is encoded as DQPSK and not part DBPSK and part DQPSK. 
The
decoding algorithm then fails.

--Thanks