Ofdm question

Hi everyone, I have a question about ofdm benchmark. If I use
benchmark_tx.py and benchmark_rx.py without any change I have an error
rate below 10%.
However, if I only modify the benchmark_tx.py and I add only a
sleep(1) between packets transmissions like is shown in the following

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

then the packets error rate is above 50%. Could someone explain me
where is the problem and how can I solve it?

Thanks in advance,

Pablo B…