Channel estimation methods for preamble-based OFDM/OQAM modulations

OFDM/OQAM is a special type of multi-carrier modulation that can be considered as an alternative to conventional OFDM with cyclic prefix (CP) for transmission over multipath fading channels. Indeed, as it requires no guard interval, it has the advantage of a theoretically higher spectral efficiency. Furthermore if the pulse shape is well-localized in frequency, the resulting OFDM/OQAM signal satisfies stringent spectrum requirements. However, the classical channel estimation methods used for OFDM cannot be directly applied to OFDM/OQAM. In this paper we present an analysis of this problem and we describe a method for “pseudo” perfect channel estimation in OFDM/OQAM. Then we introduce two new realistic preamblebased channel estimation methods. The performance results are obtained by considering an IEEE 802.22 channel model with OFDM/OQAM and the proposed channel estimation methods are compared to the ones obtained with CP-OFDM.