As a promising 6G technology, integrated sensing and communication (ISAC) gains growing interest. ISAC provides integration gain via sharing spectrum, hardware, and software. However, concerns exist regarding its sensing performance when compared to the dedicated radar. To address this issue, the advantages of widely deployed networks should be utilized. This paper proposes networked collaborative sensing (NCS) using multi-domain measurements (MM), including range, Doppler, and two-dimension angles. For the NCS-MM architecture, this paper proposes a novel multi-domain decoupling model and a novel guard band-based protocol. The proposed model simplifies multi-domain derivations and algorithm designs, and the proposed protocol conserves resources and mitigates NCS interference. In terms of performance limits, this paper derives the Cram\'er-Rao lower bound (CRLB) of position and velocity estimations in NCS-MM. An accumulated single-dimension channel model is proposed, which is proven to be equivalent to that of the multi-dimension model. The algorithms of both MM estimation and fusion are proposed. An arbitrary-dimension Newtonized orthogonal matched pursuit (AD-NOMP) is proposed to accurately estimate grid-less MM. The degree-of-freedom (DoF) of MM is analyzed, and a novel DoF-based two-stage weighted least squares (TSWLS) is proposed to reduce complexity without DoF loss. The numerical results show that the proposed algorithms approach their performance limits.

翻译：作为一项前景广阔的6G技术，集成感知与通信（ISAC）正获得日益增长的关注。ISAC通过共享频谱、硬件和软件实现集成增益。然而，与专用雷达相比，其感知性能仍存在疑虑。为解决这一问题，应充分利用广泛部署的网络优势。本文提出一种利用多域测量（MM）的网络化协同感知（NCS）方法，测量域包括距离、多普勒频移与二维角度。针对NCS-MM架构，本文提出一种新颖的多域解耦模型和一种基于保护带的新型协议。所提模型简化了多域推导与算法设计，所提协议则能节约资源并减轻NCS干扰。在性能极限方面，本文推导了NCS-MM中位置与速度估计的克拉美-罗下界（CRLB）。提出了一种累积单维信道模型，并证明其与多维模型等效。同时提出了MM估计与融合算法：提出任意维度牛顿化正交匹配追踪（AD-NOMP）算法以实现无网格MM的精确估计；分析了MM的自由度（DoF），并提出基于DoF的两阶段加权最小二乘（TSWLS）方法，在保持DoF不变的前提下降低计算复杂度。数值结果表明，所提算法能够逼近其理论性能极限。