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 dedicated radar systems. To address this issue, the advantages of widely deployed networks should be utilized, and this paper proposes networked collaborative sensing (NCS) using multi-domain measurements (MM), including range, Doppler, and two-dimension angle of arrival. In 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. To determine the performance limits, this paper derives the Cram\'er-Rao lower bound (CRLB) of three-dimension position and velocity in NCS-MM. An accumulated single-dimension channel model is used to obtain the CRLB of MM, 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 equations without DoF loss. The numerical results show that the performances of the proposed algorithms are close to their performance limits.

翻译：作为一项有前景的6G技术，通感一体化（ISAC）正获得越来越多的关注。通感一体化通过共享频谱、硬件和软件实现一体化增益。然而，与专用雷达系统相比，其感知性能仍引发关注。为解决该问题，应充分利用广泛部署网络的优势。本文提出一种基于多域测量（MM）的网络协同感知（NCS）架构，其中多域测量包括距离、多普勒及二维到达角。在NCS-MM架构中，本文提出新颖的多域解耦模型与基于保护带的协议。所提模型简化了多域推导与算法设计，所提协议则节约资源并缓解NCS干扰。为确定性能极限，本文推导了NCS-MM中三维位置与速度的克拉美-罗下界（CRLB）。采用累积单维信道模型获取MM的CRLB，并证明该模型与多维模型等效。同时提出MM估计与融合的算法：提出任意维度牛顿化正交匹配追踪（AD-NOMP）以精确估计无网格MM；分析MM的自由度（DoF），并提出基于自由度的新型两阶段加权最小二乘（TSWLS）算法，在无自由度损失条件下减少方程数量。数值结果表明，所提算法的性能接近其理论极限。