5G超密集网络中的联合设备定位和时钟同步
Joint Device Positioning and Clock Synchronization in 5G Ultra-Dense Networks
摘要：
在本文中，我们将讨论5G无线接入网络中高效准确的设备定位和跟踪的前景和关键技术。建立在超密集网络的前提下，以及在接入节点（AN）的多载波波形和天线阵列的采用，我们首先制定了扩展的卡尔曼滤波器（EKF）为基础的解决方案，计算高效的联合估计和跟踪的到达时间（ToA）和到达方向（DoA）的用户节点（UN）使用上行链路参考信号。然后，提出了第二EKF阶段，以便将来自一个或多个AN的各个DoA/ToA估计融合到UN位置估计中。由于所有处理都在网络侧进行，因此UN侧的计算复杂度和能耗保持在最低水平。本文中提出的级联EKF还考虑了UN和AN之间不可避免的相对时钟偏移，从而获得接入链路的可靠时钟同步作为有价值的副产品。建议的级联EKF方案，然后修改和扩展到更一般的和具有挑战性的情况下，不仅联合国有时钟偏移对网络时间，而且AN本身并不相互同步的时间。最后，在基于METIS项目的室外马德里地图模型以及完整的基于光线追踪的传播建模的基础上，提供了在现实的5G网络设置上对所提出的解决方案的全面性能评估。所获得的结果清楚地表明，通过使用所开发的方法，移动设备的亚米级定位和跟踪精度在未来以低于6 GHz频率运行的5G无线电接入网络中确实在技术上是可行的，尽管存在与时钟偏移相关的现实假设，甚至可能在不同步的网络元素下。
英文摘要：
In this article, we address the prospects and key enabling technologies for highly efficient and accurate device positioning and tracking in 5G radio access networks. Building on the premises of ultra-dense networks as well as on the adoption of multicarrier waveforms and antenna arrays in the access nodes (ANs), we first formulate extended Kalman filter (EKF)-based solutions for computationally efficient joint estimation and tracking of the time of arrival (ToA) and direction of arrival (DoA) of the user nodes (UNs) using uplink reference signals. Then, a second EKF stage is proposed in order to fuse the individual DoA/ToA estimates from one or several ANs into a UN position estimate. Since all the processing takes place at the network side, the computing complexity and energy consumption at the UN side are kept to a minimum. The cascaded EKFs proposed in this article also take into account the unavoidable relative clock offsets between UNs and ANs, such that reliable clock synchronization of the access-link is obtained as a valuable by-product. The proposed cascaded EKF scheme is then revised and extended to more general and challenging scenarios where not only the UNs have clock offsets against the network time, but also the ANs themselves are not mutually synchronized in time. Finally, comprehensive performance evaluations of the proposed solutions on a realistic 5G network setup, building on the METIS project based outdoor Madrid map model together with complete ray tracing based propagation modeling, are provided. The obtained results clearly demonstrate that by using the developed methods, sub-meter scale positioning and tracking accuracy of moving devices is indeed technically feasible in future 5G radio access networks operating at sub-6GHz frequencies, despite the realistic assumptions related to clock offsets and potentially even under unsynchronized network elements.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
