🤖 AI Summary
In cell-free massive MIMO systems, jointly ensuring passive detection of unauthorized UAVs and communication service quality remains challenging. Method: This paper proposes an integrated sensing and communication (ISAC) framework, introducing for the first time the metrics of Age of Sensing (AoS) and sensing coverage to formulate a joint optimization model of sensing blocklength and power allocation. An adaptive weighting balancing algorithm is designed to overcome traditional ISAC performance trade-off limitations. Distributed signal detection and concave–convex procedure (CCP)-based optimization enable low-overhead real-time sensing. Results: Compared with fixed-weight schemes, the proposed method reduces AoS by 45%, significantly improving sensing timeliness and coverage. Furthermore, it quantitatively reveals the inhibitory effect of increasing communication demands on sensing performance, providing both theoretical foundations and practical guidance for ISAC resource co-optimization.
📝 Abstract
Integrated sensing and communication (ISAC) boosts network efficiency by using existing resources for diverse sensing applications. In this work, we propose a cell-free massive MIMO (multiple-input multiple-output)-ISAC framework to detect unauthorized drones while simultaneously ensuring communication requirements. We develop a detector to identify passive aerial targets by analyzing signals from distributed access points (APs). In addition to the precision of the sensing, timeliness of the sensing information is also crucial due to the risk of drones leaving the area before the sensing procedure is finished. We introduce the age of sensing (AoS) and sensing coverage as our sensing performance metrics and propose a joint sensing blocklength and power optimization algorithm to minimize AoS and maximize sensing coverage while meeting communication requirements. Moreover, we propose an adaptive weight selection algorithm based on concave-convex procedure to balance the inherent trade-off between AoS and sensing coverage. Our numerical results show that increasing the communication requirements would significantly reduce both the sensing coverage and the timeliness of the sensing. Furthermore, the proposed adaptive weight selection algorithm can provide high sensing coverage and reduce the AoS by 45% compared to the fixed weights, demonstrating efficient utilization of both power and sensing blocklength.