  In this paper, we study resource allocation algorithm design for secure
multi-user downlink ultra-reliable low latency communication (URLLC). To
enhance physical layer security (PLS), the base station (BS) is equipped with
multiple antennas and artificial noise (AN) is injected by the BS to impair the
eavesdroppers' channels. To meet the stringent delay requirements in secure
URLLC systems, short packet transmission (SPT) is adopted and taken into
consideration for resource allocation design. The resource allocation algorithm
design is formulated as an optimization problem for minimization of the total
transmit power, while guaranteeing quality-of-service (QoS) constraints
regarding the URLLC users' number of transmitted bits, packet error
probability, information leakage, and delay. Due to the non-convexity of the
optimization problem, finding a global solution entails a high computational
complexity. Thus, we propose a low-complexity algorithm based successive convex
approximation (SCA) to find a sub-optimal solution. Our simulation results show
that the proposed resource allocation algorithm design ensures the secrecy of
the URLLC users' transmissions, and yields significant power savings compared
to a baseline scheme.
