Virtual Antenna Array and Fractional Fourier Transform-Based TOA Estimation for Wireless Positioning

Virtual Antenna Array and Fractional Fourier Transform-Based TOA Estimation for Wireless Positioning
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DOI：
10.3390/s19030638
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发表时间：
2019-02
期刊：
Sensors (Basel, Switzerland)
影响因子：
--
通讯作者：
Zhigang Chen;Lei Wang;Mengya Zhang
Zhigang Chen;Lei Wang;Mengya Zhang
中科院分区：
其他
文献类型：
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作者：
Zhigang Chen;Lei Wang;Mengya Zhang

文献摘要

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本文提出了一种用于 OFDM WLAN 系统的新型虚拟天线阵列和基于分数傅里叶变换 (FRFT) 的二维超分辨率到达时间 (TOA) 估计算法。该算法利用直线或准直线移动轨迹上等间隔位置的信道频率响应（CFR），即虚拟天线阵列的CFR，来提取多径的TOA信息。同时，使用新的类线性调频二次函数来近似信道多径在空间维度上的相位变化，这比传统的线性函数更合理，特别是对于相对较大的虚拟天线阵列尺寸。利用FRFT域中类线性调频多径能量集中的特性，首先利用FRFT分离出类线性调频多径分量，然后对分离的多径分量进一步采用现有的频域TOA估计方法，得到多径的TOA估计。因此，该算法能够更多地利用多径在空间维度上的特性，从而能够有效提升多径分辨率，在不需要真实天线阵列的情况下实现更好的多径TOA估计性能。仿真结果证明了该算法的有效性。
In this paper, a novel virtual antenna array and fractional Fourier transform (FRFT)-based 2-dimension super-resolution time-of-arrival (TOA) estimation algorithm for OFDM WLAN systems has been proposed. The proposed algorithm employs channel frequency responses (CFRs) at the equi-spaced positions on a line or quasi-line moving trajectory, i.e., the CFRs of a virtual antenna array, to extract multipaths’ TOA information. Meanwhile, a new chirp-like quadratic function is used to approximate the channel multipaths’ phase variation across the space dimension, which is more reasonable than the traditional linear function, especially for relatively big virtual antenna array sizes. By exploiting the property of chirp-like multipaths’ energy concentration in the FRFT domain, the FRFT can be first used to separate chirp-like multipath components, then the existing TOA estimation methods in frequency domain can be further employed on the separated multipath components to obtain the multipaths’ TOA estimates. Therefore, the proposed algorithm can make more use of the multipaths’ characteristics in the space dimension, thus it can efficiently enhance the multipath resolution and achieve better multipaths’ TOA estimation performance without requiring a real antenna array. Simulation results demonstrate the effectiveness of the proposed algorithm.