  In this paper, we propose a novel scheme to estimate the six dimensional (6D)
motion parameters of dynamic target for monostatic integrated sensing and
communications (ISAC) system. We first provide a generic ISAC framework for
dynamic target sensing based on massive multiple input and multiple output
(MIMO) array. Next, we derive the relationship between the sensing channel of
ISAC base station (BS) and the 6D motion parameters of dynamic target. Then, we
employ the array signal processing methods to estimate the horizontal angle,
pitch angle, distance, and virtual velocity of dynamic target. Since the
virtual velocities observed by different antennas are different, we adopt plane
fitting to estimate the dynamic target's radial velocity, horizontal angular
velocity, and pitch angular velocity from these virtual velocities. Simulation
results demonstrate the effectiveness of the proposed 6D motion parameters
estimation scheme, which also confirms a new finding that one single BS with
massive MIMO array is capable of estimating the horizontal angular velocity and
pitch angular velocity of dynamic target.
