  Millimeter-wave (mmWave) radar is widely used in vehicles for applications
such as adaptive cruise control and collision avoidance. In this paper, we
propose an IEEE 802.11ad-based radar for long-range radar (LRR) applications at
the 60 GHz unlicensed band. We exploit the preamble of a single-carrier (SC)
physical layer (PHY) frame, which consists of Golay complementary sequences
with good correlation properties, as a radar waveform. This system enables a
joint waveform for automotive radar and a potential mmWave vehicular
communication system based on IEEE 802.11ad, allowing hardware reuse. To
formulate an integrated framework of vehicle-to-vehicle (V2V) communication and
LRR based on a mmWave consumer wireless local area network (WLAN) standard, we
make typical assumptions for LRR applications and incorporate the full duplex
radar assumption due to the possibility of sufficient isolation and
self-interference cancellation. We develop single- and multi-frame radar
receiver algorithms for target detection as well as range and velocity
estimation within a coherent processing interval. Our proposed radar processing
algorithms leverage channel estimation and time-frequency synchronization
techniques used in a conventional IEEE 802.11ad receiver with minimal
modifications. Analysis and simulations show that in a single target scenario,
a Gbps data rate is achieved simultaneously with cm-level range accuracy and
cm/s-level velocity accuracy. The target vehicle is detected with a high
probability of detection ($>$99.9$\%$) at a low false alarm of 10$^{-6}$ for an
equivalent isotropically radiated power (EIRP) of 43 dBm up to a vehicle
separation distance of 200 m.
