Exact Intersymbol Interference Analysis for Upsampled OFDM Signals with Symbol Timing Errors

Heon HUH  Feng LU  James V. KROGMEIER  

IEICE TRANSACTIONS on Communications   Vol.E100-B   No.8   pp.1472-1479
Publication Date: 2017/08/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2016EBP3433
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
orthogonal frequency-division multiplexing,  blind synchronization,  minimum interference power,  symbol timing,  oversampling,  upsampling,  

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In OFDM systems, link performance depends heavily on the estimation of symbol-timing and frequency offsets. Performance sensitivity to these estimates is a major drawback of OFDM systems. Timing errors destroy the orthogonality of OFDM signals and lead to inter-symbol interference (ISI) and inter-carrier interference (ICI). The interference due to timing errors can be exploited as a metric for symbol-timing synchronization. In this paper, we propose a novel method to extract interference components using a DFT of the upsampled OFDM signals. Mathematical analysis and formulation are given for the dependence of interference on timing errors. From a numerical analysis, the proposed interference estimation shows robustness against channel dispersion.