How to see what kind of mac/phy schemes?

GNU Radio
1

Hi,

I’m a gnu radio newbie. Can anyone tell me how to see what kind of
mac/phy
schemes gnu radio comes with, and what is the capacity of gnu radio? Or
is
there any documentation about this?

Thanks.
Y

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2

Please, I want to know about some details of blocks at
MAC and PHY layer. E.g., what kind of MAC modules or blocks that gnu
radio can provide us? I’ve read the tutorial here
http://www.nd.edu/~jnl/sdr/docs/tutorials/9.html#tthFtNtAAB but I can
not find what I want.

Do you guys know whether there is any documentation about those blocks?
Or
would you kindly tell me where I can find them in the source code
directory? Since I’m the only one in our group who is exploring gnu
radio, it’s difficult to read or search without help of others. Thanks
for help.

yyzhuang wrote:

Hi,

I’m a gnu radio newbie. Can anyone tell me how to see what kind of mac/phy
schemes gnu radio comes with, and what is the capacity of gnu radio? Is
there any documentation about this?

Thanks.
Y

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3

Y,

Have you looked through the code available in in the
gnuradio-examples folder? I t covers the basic of getting started
with the available blocks.

Also you might want to have a look at the simple gnuradio manual
which covers all of the available functions:
www.ece.jhu.edu/~cooper/SWRadio/Simple-Gnuradio-User-Manual-v1.0.pdf

If you downloaded (or checked out) the source, most of the code you
will want to look at is in the gnuradio-core folder. Both the python
and C code is there so you can see how to instantiate things and how
to create blocks. A good place to start would be the converter blocks
(ie, float_to_char), they are nice and simple.

Finally, if you want to write a MAC/PHY block for use with gnuradio
a good place to start would be be here (probably before you dive into
the code):
http://www.gnu.org/software/gnuradio/doc/howto-write-a-block.html

Jason

4

Thanks Jason.

I’m reading some example scripts in the gnuradio-examples folder, and I
particularly interested in the
/gnuradio-examples/python/digital/tunnel.py.
What we are interested in is particularly in the MAC/PHY blocks. Do you
know
in which directory under gnuradio-core we can find it?

Thanks for help.

Best,
Y

Jason U. wrote:

Do you guys know whether there is any documentation about those blocks?

Hi,
–

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5

There is currently no MAC layer support. There has been some work in
supporting it through the new m-blocks, but I still believe there are
pieces missing for tightly timed CSMA MACs. The timestamps are great
for TDMA, but CSMA is still kind of left in the dark.

I’m working on it as research right now. I’ve implemented a CSMA and
TDMA MAC, but they’re currently not available. Hopefully I can wrap
them up by the end of August and release them.

  • George
6

On Wed, Jul 23, 2008 at 09:06:57AM -0700, yyzhuang wrote:

As I see from the simple manual and some source code, most of the blocks are
designed for PHY layer or hard ware. Should all the MAC layer functions
implemented by python application, or are there any existing MAC layer
blocks we can use directly? Thanks for help.

Y

Hi Y,

In the relatively near term, I’ll be gluing the message blocks
(m-blocks) and the GR flow graphs together. When that is complete, I
expect that what you’ll find is that the natural place to write MAC
layer stuff is in m-blocks while using the flow graph to implement the
PHY. This will use inband signaling on the USRP1 and/or USRP2 and
will give us precise control of time of transmission.

Eric

7

As I see from the simple manual and some source code, most of the blocks
are
designed for PHY layer or hard ware. Should all the MAC layer functions
implemented by python application, or are there any existing MAC layer
blocks we can use directly? Thanks for help.

Y

yyzhuang wrote:

with the available blocks.

MAC and PHY layer. E.g., what kind of MAC modules or blocks that gnu

Discuss-gnuradio Info Page

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8

Eric B. wrote:

In the relatively near term, I’ll be gluing the message blocks
(m-blocks) and the GR flow graphs together. When that is complete, I
expect that what you’ll find is that the natural place to write MAC
layer stuff is in m-blocks while using the flow graph to implement the
PHY. This will use inband signaling on the USRP1 and/or USRP2 and
will give us precise control of time of transmission.

Eric is right though. Despite my release of my own MACs, they are
forced to use a hacked up version of GMSK I wrote from a lack of glue
between the m-blocks and GR flow graphs… and no C++ daughterboard
support shoves you in to using a RFX2400 MIMO-B card. So, true MAC
support is pending on more.

  • George
9

On Wed, Jul 23, 2008 at 12:37:03PM -0400, George N. wrote:

Eric is right though. Despite my release of my own MACs, they are forced
to use a hacked up version of GMSK I wrote from a lack of glue between the
m-blocks and GR flow graphs… and no C++ daughterboard support shoves you
in to using a RFX2400 MIMO-B card. So, true MAC support is pending on
more.

  • George

Expect to see the C++ daughterboard support in 2 - 3 weeks.

Eric

10

Hi Eric,

I haven’t seen tutorials about how to use m-blocks yet. I’m curious and
want
to see how it works, although I’m not sure what I can get from it. Are
there
any examples about how to use the m-blocks in gnuradio-examples? Thanks

Y

Eric B. wrote:

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11

Thanks George. I’m still exploring Gnu Radio. Since I’m a student in
Computer
Science, I know very little about PHY and hardware, but our group will
work
with Electrical Engineering people as well.

Hope to see the new mac blocks.
Y

George N. wrote:

  • George

gnuradio-examples folder? I t covers the basic of getting started
to create blocks. A good place to start would be the converter blocks

Please, I want to know about some details of blocks at
radio, it’s difficult to read or search without help of others. Thanks

Is

Discuss-gnuradio Info Page

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12

yyzhuang wrote:

Thanks George. I’m still exploring Gnu Radio. Since I’m a student in Computer
Science, I know very little about PHY and hardware, but our group will work
with Electrical Engineering people as well.

I’m of a CS background, so I know exactly what you mean. Hang in there,
what Eric & crew have come up with for MAC support through m-blocks, and
my additions for more fine-grained MACs, should be easy to use with your
background.

  • George
13

Really thanks for the efforts. Surely more stuff will be added in the
future.
Maybe some day we can build up the entire protocol stack.

George N. wrote:

[email protected]
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14

yyzhuang wrote:

Really thanks for the efforts. Surely more stuff will be added in the future.
Maybe some day we can build up the entire protocol stack.

I think that GR has been great for PHY development and testing. If you
follow academic research at all in the CS network realm, you’ll find
that a trend has been PHY techniques to increase capacity of wireless
networks due to MAC inefficiencies. Like, Partial Packet Recovery (hi
Kyle), and in this years SIGCOMM conference “ZigZag.” All of these
works have used GR because of its PHY flexibility to evaluate these
kinds of approaches, which no other open source platform has been able
to provide as well as GR.

The MAC stuff is in the process, which I think we will then hopefully
see more research in MAC protocols done on GNU Radio. This puts it
further up the protocol stack… and then from there, we only work
further up :slight_smile:

  • George
15

http://gnuradio.org/trac/wiki/OtherCode

This is what I found:

BBN has written 802.11 code under funding from DARPA.

To get the code: cvs -d [email protected]:/cvs/adroitgrdevel co
adroitgrdevel. After GNU Radio is installed, build it using
bootstrap/configure/make install to the same prefix.

This has been tested on NetBSD, and reported to work on Linux.

The following has been reported working

* ? Mb/s transmit and receive without Barker code
* 1 Mb/s receive with the Barker code

Those experimenting with the code should be familiar with both GNU Radio
and
802.11; this is not a good area for beginners.

George N. wrote:

follow academic research at all in the CS network realm, you’ll find
further up :slight_smile:

  • George

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