Gnuradio land speed record?

I’m curious what people do with the wideband capability of the
gnuradio/usrp and what is the widest bandwidth signal one can really
process with available computers?

For reference I have a ~2.4 GHz core 2 duo laptop. For a 200 kHz FM
demodulator I consume about 40% of one cpu. That’s pretty much the
simplest useful thing anyone can do so that maps to my laptop might be
able to process 1 MHz bandwidth continuously.

Similarly, my hard drive can’t really keep up with 32 Mbyte/s recording.
So if samples are 16-bit and you really can’t afford lost data it seems
like recording is limited to maybe 10 MHz or so bandwidth.

However, with gigabit Ethernet you can send 100 Mbyte/s or more. What’s
the most anyone has recorded or processed continuously? What level of
compexity was the processing?

Thanks,
Clark

On 07/30/2010 09:33 AM, Clark P. wrote:

Similarly, my hard drive can’t really keep up with 32 Mbyte/s
recording. So if samples are 16-bit and you really can’t afford lost
data it seems like recording is limited to maybe 10 MHz or so
bandwidth.

However, with gigabit Ethernet you can send 100 Mbyte/s or more.
What’s the most anyone has recorded or processed continuously? What
level of compexity was the processing?

With RAID arrays or SSDs, it isn’t that hard anymore to sustain 100 MB/s
recording to disk. With 4 and 6 core systems and the i7 architecture
you can get more than 5X the performance of your laptop.

There are a lot of applications using the full 25 MHz of RF bandwidth.
You just need to pay a lot of attention to efficiency of your program
and algorithms.

Matt

On 07/30/2010 01:19 PM, Daniel H. wrote:

With RAID arrays or SSDs, it isn’t that hard anymore to sustain 100
hardware and custom software, but the fundamentals are the same.
available is almost certainly not something you want to look at without
reading the license very carefully, but here’s the link to the project
website:

I don’t think you need to read the license carefully to realize you do
not want to download the code.

  1. No commercial use clause.
  2. You cannot distribute derived works.
  3. You grant MS the right to use your modifications to the code.

Even if you are in an academic situation, you need to think about your
future in the commercial space before looking at the code.

Philip

On 07/30/2010 01:01 PM, Matt E. wrote:

For reference, an early version of my IRA radio astronomy receiver was
able to do single-channel
at 16MHz bandwidth, using a Core 2 Extreme 9770 and 8GB of memory and
a USRP1.

The IRA code does a number of things

 o compute total power over the entire bandwidth
 o compute an FFT with 1Hz resolution (that's a 16 million point 

FFT)
o do a SETI analysis of the resulting FFT
o do a transient signal analysis of the total power data
o run a narrowband interference filter based on an FFT filter
o run a GUI with lots of bells 'n whistles


Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

With RAID arrays or SSDs, it isn’t that hard anymore to sustain 100 MB/s
recording to disk. With 4 and 6 core systems and the i7 architecture you can
get more than 5X the performance of your laptop.

There are a lot of applications using the full 25 MHz of RF bandwidth. You
just need to pay a lot of attention to efficiency of your program and
algorithms.

For ‘speed record’ type information, you might be interested in SORA, a
software radio project from Microsoft Research. They use different
hardware and custom software, but the fundamentals are the same.

As Matt points out, efficiency is a function of engineering. Using
modern
processors, 64-bit architecture, multicore, software LUTs, and a variety
of other optimizations they were able to fully process 802.11g signals
of
20 MHz bandwidth and sustain reception of 54 Mbps signals including
Viterbi decoding, etc. I see no reason this couldn’t be done with
USRP(2) / GNU Radio… but looking at Microsoft’s author list they had a
lot of developers working pretty hard on it!

There’s not a ton of detail in the original paper, and what code is
available is almost certainly not something you want to look at without
reading the license very carefully, but here’s the link to the project
website:

http://research.microsoft.com/en-us/projects/sora/

and the original paper:

http://research.microsoft.com/apps/pubs/default.aspx?id=79927

Dan


process with available computers?
just need to pay a lot of attention to efficiency of your program and
20 MHz bandwidth and sustain reception of 54 Mbps signals including

and the original paper:

http://research.microsoft.com/apps/pubs/default.aspx?id=79927

Dan

Thanks that’s a good data point! So a huge corporation with infinite
resources tops out at about 20 MHz sustained processing of what I would
call a real world practical signal. -Clark


process with available computers?

You just need to pay a lot of attention to efficiency of your program
and algorithms.

Matt

Good point, if you remove the CPU bottleneck and go straight to storage
you can do 100 MByte/s. Now is gigE the best for that or would SATA be
better? Seems like once you buy the networking and storage equipment
you’ve blown your budget relative to the usrp price.

Yeah, I’d be interested in what those 25 MHz apps are. Maybe we need a
contest for widest bandwidth, practical, most useful application on
gnuradio. One ground rule though would be that the cost of the
processing device has to be less than the USRP2, for example.

Thanks,
Clark


a USRP1.

Discuss-gnuradio mailing list
[email protected]
http://lists.gnu.org/mailman/listinfo/discuss-gnuradio

Now was the FFT continuous, i.e. you got one output bin for every input
sample or you did snapshots? Thanks

On Fri, 30 Jul 2010, Clark P. wrote:

and the original paper:

http://research.microsoft.com/apps/pubs/default.aspx?id=79927

Dan

Thanks that’s a good data point! So a huge corporation with infinite resources tops out at about 20 MHz sustained processing of what I would call a real world practical signal. -Clark

I think that should be thought of as a lower bound not an upper bound
:).
They accomplished their goal of handling dot11g and haven’t (that I’m
aware of) moved on to anything harder (yet).

Aside: reading the paper doesn’t come with any licensing terms, and
there’s even ASM code in the appendix for a SIMD-enabled FIR filter at
the
end.

Dan


Date: Fri, 30 Jul 2010 10:19:35 -0700

algorithms.
Viterbi decoding, etc. I see no reason this couldn’t be done with
and the original paper:
Their infinite resources are in fact limited by their management’s mindset and inability to think clearly about the
consequences of their business model, the impact of the Internet, etc. A guy like Ballmer is just a much a reason why
Linux exists as is Linus himself. His rhetoric about GPL being a cancer, Linux developers are communists, etc. has
provided “infinite inspiration” to the guys with limited resources.

SORA may be a useful data point, but advise to carefully consider the source.

-Jeff

This is true. And I seem to recall Gates saying basically that the
reason windows is coded so inefficiently is because the hardware will
always increase faster than Microsofts bad coding. I have an internet
explorer process running right now that’s use 80 megabytes of memory!
Years ago we ran an entire graphical interface and gui in 64 kByte on
the commodore 64.

Clark P. wrote:

recording. So if samples are 16-bit and you really can’t afford lost

Thanks,
Clark


Discuss-gnuradio mailing list
[email protected]
http://lists.gnu.org/mailman/listinfo/discuss-gnuradio

I use the 25MHz sample-rate to test algorithms. In one application I
transmit during 0.1ms and then use 10ms to process the data. This is for
doing research on algorithms. It’s still different from pure off-line
processing as I can do feedback, MAC-algorithms and so on.

I would actually like to have more than 25MHz maybe 100MHz to be able to
work with bandwidths such as 40MHz.

BR/
Per

On Jul 30, 2010, at 1:30 PM, Philip B. wrote:

I don’t think you need to read the license carefully to realize you do not want to download the code.

  1. No commercial use clause.
  2. You cannot distribute derived works.
  3. You grant MS the right to use your modifications to the code.

Even if you are in an academic situation, you need to think about your future in the commercial space before looking at the code.

On Jul 30, 2010, at 3:48 PM, Daniel H. wrote:

Aside: reading the paper doesn’t come with any licensing terms, and there’s even ASM code in the appendix for a SIMD-enabled FIR filter at the end.

Old topic, but just to be complete (since I was looking into it anyway):

The license is found when you try to download the SDK:

<
http://research.microsoft.com/en-us/downloads/35a929d6-0cb0-4318-968a-69d05c9bbc65/

Adding to what Philip wrote above: The code runs on Windows only, and
requires the use of their special “radio control board” -as well as- a
USRP1/2 or WARP as the radio front-end to do actual over the air
communications. - MLD

On 07/30/2010 09:33 AM, Clark P. wrote:
recording to disk. With 4 and 6 core systems and the i7 architecture you can

reading the license very carefully, but here’s the link to the project

Thanks that’s a good data point! So a huge corporation with
infinite resources tops out at about 20 MHz sustained
processing of what I would call a real world practical signal.

Their infinite resources are in fact limited by their management’s
mindset and inability to think clearly about the
consequences of their business model, the impact of the Internet, etc.
A guy like Ballmer is just a much a reason why
Linux exists as is Linus himself. His rhetoric about GPL being a
cancer, Linux developers are communists, etc. has
provided “infinite inspiration” to the guys with limited resources.

SORA may be a useful data point, but advise to carefully consider the
source.

-Jeff

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