Ofdm benchmark issue

GNU Radio
1

Hi everyone, I am newbie on gnuradio and I have a question about ofdm
benchmark. If I use benchmark_tx.py and benchmark_rx.py I have a good
performance, (an error rate below 10%).
However, if I only modify the benchmark_tx.py and I add only a
time.sleep(1) between send_pkt(payload) like is shown in the
following code of the benchmark_tx.py:

while n < nbytes:
if options.from_file is None:
data = (pkt_size - 2) * chr(pktno & 0xff)
else:
data = source_file.read(pkt_size - 2)
if data == ‘’:
break;
payload = struct.pack(’!H’, pktno & 0xffff) + data
send_pkt(payload)
n += len(payload)
print (n)
if options.discontinuous and pktno % 5 == 4:
time.sleep(1)
pktno += 1
time.sleep(1) # this is the line added
send_pkt(eof=True)

In this case, the packets error rate is above 50% and there are some
underruns on the transmitting screen.

Could someone explain me where is the problem and how can I solve it?

Thanks in advance,

Pablo B…

2

On Thu, Feb 14, 2013 at 2:44 PM, Pablo B. [email protected]
wrote:

    else:
    time.sleep(1)                     # this is the line added

This code must not be setting the burst conditions for the UHD driver
correctly. There’s some ongoing work that’s overhauling the OFDM code
for a
lot of the major advancements in GNU Radio since these benchmark scripts
were first written. I think this is the best place to look at that code
development:

git://github.com/benreynwar/gnuradio.git

Using the branch ‘ofdm’. Not sure how usable it is right now, though.

Tom