Electronically steerable parasitic array radiator (ESPAR) antenna is a novel low-cost technique to gain comparable diversity order to that of using multiple antennas while maintaining one radio frequency (RF) front-end, low power consumption, and simple wiring at the mobile receiver. It has huge potential to realize high energy efficiency for multiple and massive antennas systems. The main drawback of the ESPAR based OFDM system is that the channel estimation (CE) usually should be realized in time-domain with a huge computational complexity (CC) because the received signal to each parasitic element is overlapped each other both in frequency and time domain. This article will propose three ways to reduce the complexity of CE for the ESPAR-OFDM system. The parallel multi-column compressive sensing (CS) algorithm was first introduced to detect all locations of channel impulse response simultaneously using one small segment of sensing matrix. Furthermore, by exploiting the symmetrical properties of Digital Fourier transform (DFT), the size of matrix to decrease the CC of matrix operation. Finally, by selecting a small set of row vectors of sensing matrix at the receiver side, the CC involved in CS algorithm can be reduced. From the analysis and simulated results, the proposed method can obtain more than 90% CC reduction for CE of ESPAR-OFDM receiver can be confirmed.

中文翻译：

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ESPAR-OFDM接收机的信道估计的低复杂度实现

电子可控寄生阵列辐射器（ESPAR）天线是一种新颖的低成本技术，能够获得与使用多个天线相当的分集等级，同时保持一个射频（RF）前端，低功耗和移动接收机的简单接线。它具有巨大的潜力，可以为多个大型天线系统实现高能效。基于ESPAR的OFDM系统的主要缺点是，信道估计（CE）通常应在时域内以巨大的计算复杂度（CC）实现，因为到每个寄生元件的接收信号在频率和时间上都相互重叠领域。本文将提出三种降低ESPAR-OFDM系统CE复杂度的方法。首次引入并行多列压缩感测（CS）算法，以使用一小段感测矩阵同时检测通道脉冲响应的所有位置。此外，通过利用数字傅立叶变换（DFT）的对称特性，可以减小矩阵的大小，从而降低矩阵运算的CC。最后，通过在接收器侧选择一小组传感矩阵的行向量，可以减少CS算法中涉及的CC。通过分析和仿真结果，所提出的方法可以确认ESPAR-OFDM接收机的CE降低CC超过90％。矩阵的大小以减少矩阵运算的CC。最后，通过在接收器端选择一小组传感矩阵的行向量，可以减少CS算法中涉及的CC。通过分析和仿真结果，所提出的方法可以确认ESPAR-OFDM接收机的CE降低CC超过90％。矩阵的大小以减少矩阵运算的CC。最后，通过在接收器端选择一小组传感矩阵的行向量，可以减少CS算法中涉及的CC。通过分析和仿真结果，所提出的方法可以确认ESPAR-OFDM接收机的CE降低CC超过90％。