Re: [Discuss-gnuradio] In-band Signaling

[Johnathan Corgan]

On Tue, 2009-07-28 at 20:47 -0700, Jane Chen wrote:

> According to the explaination of the In-band Signaling in the link
> http://gnuradio.org/trac/wiki /InBandSignaling, In-band Signaling is
> what I need for the MAC layer implementation.. I try to find more
> information about it on the mailinglist or the Web. I am wondering if
> In-band Signaling  is not completed yet. Could anyone please tell me
> if In-band Signaling is completed in GNURadio 3.2.2 or not? It seems
> that there is no change log of the GNU Radio 3.2.2 on the download
> page or in the gnuradio-3.2.2 folder.

In-band signaling (basically, timed burst TX/RX instead of streaming)
was implemented for both USRP1 and USRP2 in their FPGAs.

However, the GNU Radio host code streaming architecture was/is
incompatible with it, and an alternative ("mblocks") that was developed
saw little usage.  I think this is primarily because it is difficult to
reuse any of the existing GNU Radio streaming blocks in conjunction with
it.

We are now focused on porting many of the features of the mblock library
into native GNU Radio blocks as part of the 3.3 development process.
This will allow (among other things) development of native GNU Radio
applications that can interact with the USRP1 and USRP2 in burst mode
vs. streaming mode.

There are users who are bypassing GNU Radio blocks altogether and
interfacing directly with low-level libusrp and libusrp2 libraries.
This allows them access to burst TX and RX functions, at the expense of
writing all their own application runtime and DSP code (OpenBTS is good
example of this.)

Johnathan