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Blind CFO Estimators for OFDM/OQAM Systems With Null Subcarriers

Tilde Fusco and Mario Tanda
Dipartimento di Ingegneria Elettronica e delle Telecomunicazioni, Universit`a di Napoli Federico II, via Claudio 21, I-80125 Napoli, Italy.
Abstract—This paper deals with the problem of blindcarrier-frequency offset (CFO) estimation in OFDM systemsbased on offset quadrature amplitude modulation(OFDM/OQAM) with null subcarriers. Specifically, by assumingthat the number of subcarriers is sufficiently large,the received signal is modeled as a complex Gaussianrandom vector (CGRV). Since the OFDM/OQAM signalresults to be a noncircular (NC) process, by exploiting thegeneralized probability density function for NC-CGRVs, theunconditional maximum likelihood (ML) algorithm for CFOestimation in non dispersive channel is proposed. Moreover,a modified version of the unconditional ML CFO estimatoris considered. The performance of the derived algorithms,assessed via computer simulation, is compared with thatof recently proposed estimators exploiting the second-ordercyclostationarity and with the Gaussian Cram´er-Rao bound.

Index Terms—Blind estimation, carrier-frequency offset,null subcarries, OFDM/OQAM systems.

Cite: Tilde Fusco and Mario Tanda, "Blind CFO Estimators for OFDM/OQAM Systems With Null Subcarriers," Journal of Communications, vol. 2, no. 3, pp. 17-23, 2007.
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