Difference between blks and blks2


#1

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


#2

On Sun, May 10, 2009 at 1:11 AM, Colby B. removed_email_address@domain.invalid
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


#3

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