Fair Integrated Sensing and Communication for Multi-UAV-Enabled Internet of Things: Joint 3-D Trajectory and Resource Optimization

Unmanned aerial vehicle (UAV) has been widely used as an aerial base station (BS) to assist the ground communications for Internet of Things (IoT) due to its wide-area coverage, high mobility and line-of-sight (LoS) communication link. In this paper, a multi-UAV enabled IoT is considered, where the UAVs provide integrated sensing and communication (ISAC) services to the IoT nodes. The radar mutual information (MI) is introduced to measure the sensing performance of ISAC from the information theory perspective. To achieve fair communications, we seek to maximize the minimum communication rate per IoT node by jointly optimizing node scheduling, transmit power and 3D trajectory of the UAV under the constraint of radar MI for each IoT node. The formulated non-convex multi-variable optimization problem is divided into three subproblems, including UAV scheduling optimization, UAV transmit power optimization, and UAV 3D trajectory optimization. The near-optimal solutions of the original optimization problem can be achieved by proposing a three-layer iterative optimization algorithm to optimize the three subproblems iteratively. The simulation results demonstrate that the proposed optimization scheme can obviously improve communication rate under the constraint of radar MI as well as achieve fair communication for each node.