Design and Evaluation of a Novel Short Prototype Filter for FBMC/OQAM Modulation

Filter-bank multi-carrier with offset quadrature amplitude modulation (FBMC/OQAM) is considered by recent research projects as one of the key enablers for the future 5G air interface. It exhibits better spectral shape and improves mobility support compared to orthogonal frequency-division multiplexing (OFDM) thanks to the use of a time and frequency localized prototype filter. The choice of this filter is crucial for FBMC/OQAM, due to its substantial impact on achieved performance and complexity levels. In the context of 5G, short frame sizes are foreseen in several communication scenarios to reduce system latency, and therefore short filters are preferred. In this context, a novel short filter allowing for near perfect reconstruction and having the same size as one OFDM symbol is proposed. Using frequency-spread (FS) implementation for the FBMC/OQAM receiver, analytical analysis and simulation results show that the proposed filter exhibits better robustness to several types of channel impairments when compared to state-of-the-art prototype filters and OFDM modulation. In addition, FS-based hardware architecture of the filtering stage is proposed, showing lower complexity than the classical polyphase network-based implementation.