IMPROVED INTERFERENCE APPROXIMATION METHOD FOR PREAMBLE-BASED CHANNEL ESTIMATION IN FBMC/OQAM

摘要

Filter bank-based multicarrier modulation (FBMC) usingoffset quadrature amplitude modulation (OQAM), knownas FBMC/OQAM (or OFDM/OQAM), provides an attractivealternative to the conventional cyclic prex-based orthogonalfrequency division multiplexing (CP-OFDM), especiallyin terms of increased robustness to frequency offsetand Doppler spread, and high bandwidth efciency. It suffers,however, from an inherent (intrinsic) imaginary intercarrier/inter-symbol interference that complicates signal processingtasks such as channel estimation (CE). Recently, theso-called interference approximation method (IAM) was proposedfor preamble-based CE. It relies on the knowledge ofthe pilot's neighborhood to approximate this interference andconstructively exploit it in simplifying CE and improving itsperformance. The IAM preamble with nulls at the neighboringtime instants that results in optimum CE performancewas recently reported. This paper investigates an extendedversion of it, which can provide signicant improvementthrough an appropriate exploitation of the interfering symbolsfrom neighboring time instants as well. Simulation resultsare presented that compare the methods, with each otherand with CP-OFDM, in both mildly and highly frequencyselectivechannels.