Analysis of Iterative ICI Cancellation Algorithm for Uplink OFDMA Systems with Carrier-Frequency Offset

Min HUANG  Xiang CHEN  Shidong ZHOU  Jing WANG  

IEICE TRANSACTIONS on Communications   Vol.E90-B   No.7   pp.1734-1745
Publication Date: 2007/07/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.7.1734
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
orthogonal frequency-division multiplex access (OFDMA),  inter-carrier interference (ICI),  carrier-frequency offset (CFO),  iterative algorithm,  interference-power-evolution (IPE) chart,  decision-feedback equalization (DFE),  

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In orthogonal frequency-division multiplex access (OFDMA) uplink, the carrier-frequency offsets (CFOs) between the multiple transmitters and the receiver introduce inter-carrier interference (ICI) and severely degrade the performance. In this paper, based on the perfect estimation of each user's CFO, we propose two low-complexity iterative algorithms to cancel ICI due to CFOs, which are denoted as the basic algorithm and the improved algorithm with decision-feedback equalization (DFE), respectively. For the basic one, two theorems are proposed that yield a sufficient condition for the convergence of iterations. Moreover, the interference-power-evolution (IPE) charts are proposed to evaluate the convergence behavior of this interference cancellation algorithm. Motivated by the IPE chart, the procedure of DFE is introduced into the iterations, which is the basic idea of the improved algorithm. For this improved algorithm, the error-propagation effect are analyzed and suppressed by an efficient stopping criterion. From IPE charts and simulation results, it can be easily observed that the basic algorithm has the same capability of ICI cancellation as the linear optimal minimum mean square error (MMSE) method, but offers lower complexity, while the improved algorithm with DFE outperforms the MMSE method in terms of the bit-error rate (BER) performance.