Cooperative Detection for MEC Aided Multi-Static ISAC Systems

This paper investigates a mobile edge computing (MEC) aided multi-static integrated sensing and communication (ISAC) system. In the considered system, each device has a task to be offloaded to MEC server for computation. Meanwhile, a sensing receiver (SR) has to detect a point target. To enhance detection probability, devices and base station (BS) collaboratively transmit radar signals and then SR detects the target of interest based on received radar echoes. Specifically, the whole task execution period is divided into two phases. In the first phase, devices offload partial of their tasks and simultaneously transmit radar signals for target sensing. In the second phase, the MEC server at the BS computes offloaded tasks and meanwhile devices along with BS transmit radar signals for sensing. Therefore, the entities in the system constitute a multi-static ISAC framework. Radar signal processing for multi-static sensing system is designed and the corresponding cooperative detection probability is derived. To ensure high energy efficiency, an optimization problem is formulated to minimize energy consumption of all devices under task computation and detection probability constraints by adjusting devices’ and BS’s beamforming, task partitioning, and phase duration allocation. This problem is efficiently solved by iteratively optimizing beamforming subproblem, time and task division subproblem through weighted minimum mean square error, successive convex approximation and search methods. Simulations verify the effectiveness of the proposed MEC aided cooperative sensing algorithm compared with non-cooperative sensing scheme.