  The performance of millimeter wave (mmWave) communications strongly relies on
accurate beamforming both at base station and user terminal sides, referred to
as beam alignment (BA). Existing BA algorithms provide initial yet coarse angle
estimates as they typically use a codebook of a finite number of discreteized
beams (angles). Towards emerging applications requiring timely and precise
tracking of dynamically changing state of users, we consider a system where a
base station with a co-located radar receiver estimates relevant state
parameters of users and simultaneously sends OFDM-modulated data symbols. In
particular, based on a hybrid digital analog data transmitter/radar receiver
architecture, we propose a simple beam refinement and initial state acquisition
scheme that can be used for beam and user location tracking in a dynamic
environment. Numerical results inspired by IEEE802.11ad parameters demonstrate
that the proposed method is able to improve significantly the communication
rate and further achieve accurate state estimation.
