  OFDM sensing is gaining increasing popularity in wideband radar applications
as well as in joint communication and radar/radio sensing (JCAS). As JCAS will
potentially be integrated into future mobile networks where OFDM is crucial,
OFDM sensing is envisioned to be ubiquitously deployed. A fast Fourier
transform (FFT) based OFDM sensing (FOS) method was proposed a decade ago and
has been regarded as a de facto standard given its simplicity. In this article,
we introduce an easy trick -- a pre-processing on target echo -- to further
reduce the computational complexity of FOS without degrading key sensing
performance. Underlying the trick is a newly disclosed feature of the target
echo in OFDM sensing which, to the best of our knowledge, has not been
effectively exploited yet.
