Multi-Node Multi-Band Cooperative Integrated Sensing and Communications: State-of-the-Art, Challenges and Opportunities

Integrated sensing and communication (ISAC), a pivotal advancement in 6G networks, can increase spectrum utilization and support innovative applications such as digital twins and smart cities. Nonetheless, existing single-node ISAC networks face challenges such as restricted coverage, limited sensing capabilities, and the inability to meet the stringent quality of service (QoS) requirements for combined sensing and communication. Multinode multi-band cooperative ISAC (MNMB-ISAC) networks have emerged as a promising strategy to overcome these challenges. In this study, we introduce a user-demand-driven MNMB-ISAC framework that exploits the advantages of ISAC, multi-node cooperative ISAC, and multi-band cooperative ISAC. This network architecture is designed to provide specialized services for a variety of communications or sensing requirements, substantially improving the network performance through cooperative resource allocation strategies. The empirical performance evaluations confirm the efficacy of the MNMB-ISAC approach in ensuring high QoS, guaranteeing mobility services, and improving edge coverage. Furthermore, we examine the challenges encountered by MNMB-ISAC and prospective research avenues. This work is expected to stimulate further breakthroughs in the domain of cooperative ISAC.