I have built a tx and a rx grc flowchart for OFDM using USRP. I found
range of the amplitude of the input is fairly small in order to get it
working (i.e., the USRP at the rx end can successfully decode the
I wound if anyone can share some thoughts about this? I’ve been stuck
for several days.
To quantify the packet reception performance, I modified
so that even when the crc test fails, the wrong packet is still fed to
output. In this way, I can evaluate the packet error rate (PER). Through
test, I found the const in multiply_const in the tx part (which
to amplitude adjustment) needs to be (0.05, 0.025). In this range, the
can be 0. However, when the const value increases, for example, to 0.06.
the PER is around 0.0044. When we further increase the const value to
the PER is above 10% or even higher. I guess this is probably because
input signal amplitude of the USRP needs to be in a certain working
However, it seems to me this range is too small. Besides, how can I find
some numerical statistics about the amplitude limitation? On the other
hand, if the amplitude is decreased to 0.02, many packets will be failed
synchronize. But I do observed that the packets successfully
are also correctly decoded. In other words, the PER is still 0, but the
number of packets correctly decoded is actually much smaller than the
number of packets sent.
I also tried to enable the two disabled blocks in the files but it is of
Thanks for any comments.