Pilot-based channel estimation for FBMC/OQAM systems under strong frequency selectivity

Abstract

Scattered pilot-aided channel estimation in offset QAM-based filter bank multicarrier (FBMC/OQAM) systems has so far been only considered for channels of mild frequency selectivity. In more demanding scenarios, the classical auxiliary pilot (AP) idea has been shown to result in severe error floors. In this paper, a novel pilot-aided channel estimation method is developed which for the first time extends the applicability of the AP idea to highly frequency selective channels. The development relies on a Taylor series approximation of the signal model, which is able to accurately and concisely describe such scenarios. The obtained channel estimate can be viewed as a linear combination of the outputs of multiple parallel analysis filter banks each employing a derivative of the original prototype filter. The reported simulation results corroborate the analysis, demonstrating the effectiveness of the proposed method in estimating channels of strong frequency selectivity.