  This paper conveys the theoretical sensing capability of a Joint
Communication and Sensing (JCAS) system that utilizes a True-Time-Delay (TTD)
array configuration. The TTD beamformer separates subcarrier beams into
different angular locations for wide-beam coverage. The bistatic sensing
performance of a TTD array configuration is modeled as a function of the number
of array elements and the fractional power supplied by the transmitter. The
sensing capability when employing a TTD array configuration is derived using
the Cram\'er-Rao Lower Bound (CRLB) of a bistatic delay-AOA(Angle Of
Arrival)-phase log-likelihood function which is obtained by cross-correlating
complex eigenvectors extracted from the quadratic time-frequency domain
representation of multicomponent phase-coded signals. The multicomponent
phase-codes used here are synchronization signals that are defined by the 5G
communications standard. The bistatic delay-AOA-phase estimation capability
whilst utilizing these signals and a TTD configuration was seen to be highly
non-linear with respect to the number of elements and fractional power supplied
for the surveillance scenario shown; an allocation of 30 antenna elements
supplied with maximum power made a sub-meter and sub-degree estimation
capability theoretically possible.

Signal Processing