Improved channel estimation in OFDM systems in the presence of CFO

TLDR: In this article, the authors considered the problem of pilot-aided accurate least squares (LS) channel estimation in the presence of carrier frequency offset (CFO) and showed how to select the pilot sequence with element values constrained to plus or minus one.

Abstract: We consider the problem of pilot-aided accurate least squares (LS) channel estimation in the presence of carrier frequency offset (CFO). We first formulate the mean square error (MSE) of the LS channel estimator in the presence of CFO and then show how to select the pilot sequence (with element values constrained to plus or minus one) that minimizes the MSE. Our main conclusion is that, in the presence of CFO accurate channel estimates can be obtained by transmitting identical pilot symbol on all subcarriers. We demonstrate our results via computer simulations.