Integrated sensing and communication (ISAC) is a cornerstone technology for 6G networks, offering unified support for high-rate communication and high-accuracy sensing. While existing literature extensively covers link-level designs, the transition toward large-scale deployment necessitates a fundamental understanding of network-level performance. This paper investigates a network ISAC model where a source node communicates with a destination via a relay network, while intermediate nodes concurrently perform cooperative sensing over specific spatial regions. We formulate a novel optimization framework that captures the interplay between multi-node routing and sensing coverage. For a one-dimensional path network, we provide an analytical characterization of the complete sensing-throughput region. Extending this to general network topologies, we establish that the sensing-throughput Pareto boundary is piecewise linear and provide physical interpretations for each segment. Our results reveal the fundamental trade-offs between sensing coverage and communication routing, offering key insights for the design of future 6G heterogeneous networks.

翻译：集成感知与通信（ISAC）是6G网络的关键技术，为高速率通信和高精度感知提供统一支持。现有文献广泛涵盖了链路级设计，而向大规模部署的过渡需要对网络级性能形成根本性理解。本文研究一种网络ISAC模型，其中源节点通过中继网络与目标节点通信，而中间节点同时在特定空间区域执行协同感知。我们构建了一个新颖的优化框架，以捕捉多节点路由与感知覆盖之间的相互作用。针对一维路径网络，我们给出了完整感知-吞吐量区域的解析表征。将此推广至一般网络拓扑，我们证明了感知-吞吐量帕累托边界是分段线性的，并为每个分段提供了物理解释。我们的结果揭示了感知覆盖与通信路由之间的基本权衡，为未来6G异构网络的设计提供了关键见解。