Enhanced time of arrival estimation and quantization for positioning in LTE networks
Enhanced time of arrival estimation and quantization for positioning in LTE networks
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增强了 LTE 网络中定位的到达时间估计和量化
DOI：
10.1109/pimrc.2016.7794634
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
I. Siomina
中科院分区：
文献类型：
--
作者：
Henrik Rydén;Ali A. Zaidi;S. M. Razavi;F. Gunnarsson;I. Siomina
观测到达时间差（OTDOA）是长期演进（LTE）网络中的下行链路定位方法，其中用户设备（UE）测量从多个基站接收的参考信号的到达时间（TOA）。 TOA 测量结果以参考信号时间差 (RSTD) 测量结果报告给网络，用于确定 UE 的位置。估计位置的准确性取决于测量和报告的 RSTD（相当于 TOA）的准确性。 UE可以通过测量估计的信道脉冲响应中的第一信道抽头的时间延迟来确定TOA。在室内环境中，这通常是一项重要的任务，因为室内环境中的现场线 (LOS) 信号可能很弱甚至不存在。本文提出了一种迭代方法来检测估计的信道脉冲响应中的第一个信道抽头。使用 ITU Macro 3D 信道模型评估所提出方法的性能。所提出的迭代方法被证明总是优于常用的固定阈值/非迭代方法。此外，本文还分析了 RSTD 量化分辨率在已经具备良好质量的 TOA 估计的情况下的影响。通过引入更高分辨率，已经表明LTE规范中当前的RSTD报告是有限的，并且可以通过更精细的RSTD报告分辨率来进一步提高定位精度。
Observed Time Difference of Arrival (OTDOA) is a downlink positioning method in Long Term Evolution (LTE) networks, in which a User Equipment (UE) measures the time of arrival (TOA) of reference signals received from multiple base stations. The TOA measurements are reported to the network in terms of reference signal time difference (RSTD) measurements, which are used to determine the position of the UE. The accuracy of the estimated position relies on the accuracy of the measured and reported RSTDs (equivalently TOAs). A UE can determine TOA by measuring the time delay of the first channel tap in the estimated channel impulse response. This is usually a nontrivial task in indoor environments where the line-of-site (LOS) signal can be weak or even non-existent. This paper proposes an iterative method for the detection of the first channel tap in an estimated channel impulse response. The performance of the proposed method is evaluated using an ITU Macro 3D channel model. The proposed iterative method is shown to always outperform a commonly used fixed threshold/non-iterative method. Furthermore, the paper analyzes the impact of RSTD quantization resolution in scenarios where a good quality of TOA estimation is already available. By introducing higher resolutions, it has been shown that the current RSTD reporting in LTE specifications is limiting, and the positioning accuracy can be further improved by a finer RSTD reporting resolution.