  In this study, a novel transmission scheme is proposed to serve radar-sensing
and communication objectives at the same time and allocated bandwidth. The
proposed transmitted frame non-orthogonally superimposes two different
waveforms, which are frequency modulated continuous-wave (FMCW) for
radar-sensing and orthogonal frequency division multiplexing (OFDM) for
communication. Also, the receiver scheme that performs channel estimation via
radar-sensing functionality without degrading data rate of communication
operation is introduced. As numerically evaluated, the proposed system achieves
good sensing accuracy even if the signal-to-noise ratio (SNR) is low, and
communication performance is only 0.6 dB less at the target bit-error rate
(BER) of 1% compared to the assumption of perfect channel state information
(CSI) without any pilot overhead over OFDM subcarriers.
