Frame detection and timing acquisition for OFDM transmissions with unknown interference
Frame detection and timing acquisition for OFDM transmissions with unknown interference
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DOI：
10.1109/twc.2010.03.091213
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发表时间：
2010-03
影响因子：
10.4
通讯作者：
L. Sanguinetti;M. Morelli;H. Poor
中科院分区：
文献类型：
--
作者：
L. Sanguinetti;M. Morelli;H. Poor
帧检测和定时捕获是正交频分复用系统中受窄带干扰（NBI）困扰的具有挑战性的任务。大多数现有的解决方案通过利用训练符号的重复结构在时域中操作，并且在NBI存在的情况下遭受相当大的性能损失。在这项工作中，提出了一种新的解决方案，其中帧检测是在频域中完成的基础上，一个合适的似然比测试。为了增加对NBI的弹性，干扰功率被视为从对应的似然函数中平均出来的滋扰参数。由此产生的测试统计量取决于分数载波频率偏移（CFO），这是很容易估计。提出了一种无需CFO估计的替代方案。在帧检测之后，测试统计量被用作定时度量，以准确地定位训练符号在接收到的数据流中的位置。计算机仿真表明，所提出的解决方案是非常强大的NBI和优于现有的替代品在严重的干扰情况下。这一优势的代价是计算负担的大幅增加。
Frame detection and timing acquisition are challenging tasks in orthogonal frequency-division multiplexing systems plagued by narrowband interference (NBI). Most existing solutions operate in the time domain by exploiting the repetitive structure of a training symbol and suffer from considerable performance loss in the presence of NBI. In this work, a novel solution in which frame detection is accomplished in the frequency domain on the basis of a suitable likelihood ratio test is presented. In order to increase the resilience to NBI, the interference power is treated as a nuisance parameter that is averaged out from the corresponding likelihood functions. The resulting test statistic depends on the fractional carrier frequency offset (CFO), which is easily estimated. An alternative scheme that dispenses from CFO estimation is also proposed. After frame detection, the test statistic is employed as a timing metric to accurately locate the position of the training symbol within the received data stream. Computer simulations indicate that the proposed solutions are remarkably robust to NBI and outperform existing alternatives in a severe interference scenario. The price for this advantage is a substantial increase in the computational burden.