Training sequence selection for frequency offset estimation in frequency selective channels

Author: Besson O.   Stoica P.  

Publisher: Academic Press

ISSN: 1051-2004

Source: Digital Signal Processing, Vol.13, Iss.1, 2003-01, pp. : 106-127

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Abstract

We consider the problem of optimal training sequence selection for frequency offset estimation in frequency-selective channels. Since it is desired that the optimal training sequence does not depend on a particular estimation method, we examine the Crame´r–Rao bound (CRB) for the problem at hand. For a fairly large class of training sequences, an expression for the asymptotic CRB is derived which depends in a simple way on the channel impulse response and the training sequence correlation. Based on the asymptotic CRB, two methods are presented to select an optimal training sequence. First, we consider a minmax problem which consists in minimizing the worst-case asymptotic CRB and whose solution is shown to be a white training sequence. Next, an expression for the training sequence that minimizes the asymptotic CRB is derived. Numerical simulations illustrate the estimation performance obtained with these training sequences.© 2002 Elsevier Science (USA)