Forum: GNU Radio 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
code:

 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)

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 Belzarena.