Overlap-Save FBMC Receivers

Abstract

Future communication systems are foreseen to support several services with different requirements. Waveform designs based on filter-bank multi-carrier with offset quadrature amplitude modulation (FBMC/OQAM) can offer interesting advantages in this context, such as low out-of-band power leakage and high spectral efficiency due to the lack of guard intervals. However, downsides of FBMC/OQAM with respect to a typical orthogonal frequency-division multiplexing (OFDM) solution include higher latency, higher complexity and difficulties in adapting some existing OFDM techniques such as MIMO Alamouti. To address these issues, novel FBMC receivers suitable for short prototype filters are proposed. Based on the Overlap-Save algorithm, the proposed receivers improve error-rate performance on multipath channels and support asynchronous communication. We show that complexity can be further reduced by efficiently processing blocks of FBMC symbols jointly, and that user mobility support can be traded off for additional complexity reductions in a flexible way through polynomial decomposition of the equalizer stage. Finally, we show that a block-Alamouti scheme can be applied, and we propose a MIMO equalizer with improved error-rate performance on time-varying channels, compared to the typical FBMC block-Alamouti equalizer.