  Orthogonal time frequency space (OTFS) is a promising alternative to
orthogonal frequency division multiplexing (OFDM) in high-mobility beyond 5G
communications. In this paper, we consider the problem of radar sensing with
OTFS joint radar-communications waveform and derive a novel OTFS radar signal
model by explicitly taking into account the intersymbol interference (ISI) and
inter-carrier interference (ICI) effects. On the basis of the new model, we
show how ISI and ICI phenomena can be turned into an advantage to surpass the
maximum unambiguous detection limits in range and velocity, arising in existing
OFDM and OTFS radar systems. Moreover, we design a generalized likelihood ratio
test based detector/estimator that can embrace ISI and ICI effects. Simulation
results illustrate the potential of embracing ISI/ICI and demonstrate its
superior detection and estimation performance over conventional baselines.
