An oversampled signal is a signal sampled at a frequency that is
higher than the Nyquist rate. WLAN signals maximize occupied bandwidth by using small
guardbands, which can pose problems for anti-imaging and anti-aliasing filters. Oversampling
increases the guardband width relative to the total signal bandwidth, which increases the
number of samples in the signal.
This function performs oversampling by using a larger IFFT and zero pad when generating an
OFDM waveform. This diagram shows the oversampling process for an OFDM waveform with
NFFT subcarriers made up of
Ng guardband subcarriers on either side of
Nst occupied bandwidth subcarriers.