  This correspondence paper studies a network integrated sensing and
communication (ISAC) system that unifies the interference channel for
communication and distributed radar sensing. In this system, a set of
distributed ISAC transmitters send individual messages to their respective
communication users (CUs), and at the same time cooperate with multiple sensing
receivers to estimate the location of one target. We exploit the coordinated
power control among ISAC transmitters to minimize their total transmit power
while ensuring the minimum signal-to-interference-plus-noise ratio (SINR)
constraints at individual CUs and the maximum Cram\'{e}r-Rao lower bound (CRLB)
requirement for target location estimation. Although the formulated coordinated
power control problem is non-convex and difficult to solve in general, we
propose two efficient algorithms to obtain high-quality solutions based on the
semi-definite relaxation (SDR) and CRLB approximation, respectively. Numerical
results show that the proposed designs achieve substantial performance gains in
terms of power reduction, as compared to the benchmark with a heuristic
separate communication-sensing design.
