  Ambiguity performance is a critical criterion in radar sensor design, which
indicates the ambiguities arising from multiple target estimation and
detection. We considered a requirement-driven selection of OFDM reference
signal (RS) patterns based on ambiguity performances for bi-static sensing in
integrated communication and sensing with minimal modifications of current RSs.
An RS pattern with a staggering offset of a linear slope that is relatively
prime to the RS comb size is suggested for standard-resolution sensing
algorithms to obtain the best ambiguity performances. Moreover, an extended
guard interval design is proposed to increase the maximum time delay, that is
inter-symbol interference (ISI) free using post-FFT sensing algorithms. The
proposed techniques are promising to extend the distance and speed without
ambiguities and ISI for sensing.
