Re: benchmark_ofdm with -s 16

Hi Mikie,

sorry for the late answer. I haven’t checked this mailing-list for about
a week.

When you’re seeing only the ‘TIMEOUT’ message, something is not right.
Let me know which daughterboards you’re using and with which options
you’re doing the benchmark.

Regards,
Hoo Chang.

From: Mikyung H. [email protected]
To: [email protected]
Sent: Tuesday, June 17, 2008 5:33:37 PM
Subject: Re: [Discuss-gnuradio] benchmark_ofdm with -s 16

Hi Hoo Chang,

This is Mikie. I am a grad student at UT Austin.
I read your entry in gnuradio mailing list.
I am trying out this example myself.
How do you know you how many packets you receive?

Running this example, I think the sender is transmitting,
but looks like the receiver cannot receive.

gr_fir_ccf: using SSE
gr_fir_fff: using SSE

some warnnings.
Then prints “TIMEOUT”

Do you have any suggestion?
Thanks!
Mikie


Hi,

when I send from the ‘benchmark_ofdm_tx.py’ with option -s 16, then
about 200
of the packets in the end are lost at the receiver side.
Might it be a problem at the code, or am I doing anything wrong or
missing
something?

These are the command I used:
…/benchmark_ofdm_tx.py -T A -f 2.45G -i 512 -M 0.04 -s 16
(Then it transmits 2500 packets each of size 16)

…/benchmark_ofdm_rx.py -R A -f 2.45G -d 256
(Then I get about 2300 to 2480 packets received at the receiver side)

More insteresting:
when I send the pre-saved data, which is saved from the
‘benchmark_ofdm_tx.py’,
direct to the USRP, then about 150 to 200 packets are lost

  • that is:
    I get about 2300 to 2370 packets received at the receiver side.

Any ideas or comments?

Thanx,
Hoo Chang.

Then prints “TIMEOUT”

Do you have any suggestion?
Thanks!
Mikie

That occurs when the receiver script sees a preamble sync message but
then
doesn’t see anything else come through. It’s a debug message that
shouldn’t
actually be there. It’s the normal operation of the receiver when it
doesn’t
see OFDM traffic.

(Then it transmits 2500 packets each of size 16)
I get about 2300 to 2370 packets received at the receiver side.
16 subcarriers is a really small number to use and it’s likely not being
picked
up by the receiver.

Tom