Looking at the ofdm receiver at ofdm_rx grc, I see that schmidl and cox
synchronisation algorithm uses sync1 and sync2 which are two ofdm
symbols that help in frequency offset correction and also timing
to detect the start of the packet.
Then there is channel estimator block in grc that again uses preamble
symbol to detect coarse frequency offset. In the entire implementation
haven’t seen the use of pilot symbols in each ofdm symbol for either
channel estimation or synchronisation. So does that mean that if you are
using a packet structure with a preamble there is no need of pilots for
I get this doubt because benchmark_rx.py which uses ofdm gives you a
terminal option saying occupied tones which can be set by user at
So if you can set or increase occupied tones to any number less than fft
length, then that means you can be flexible with increasing or
pilot symbols to a value that you want. Am I right?