Per Coefficient Filter Optimization for Rectangular and Quincunx QAM-FBMC

Abstract

Quadrature amplitude modulation based filter-bank multicarrier (QAM-FBMC) is a promising technology for future wireless communication systems. When we compare QAM-FBMC systems with the classical orthogonal frequency division multiplexing (OFDM), QAM-FBMC can provide better spectral efficiency, better confinement and lower out-of-band energy (OOBE) due to the use of well frequency-localized prototype filters. These advantages come at the cost of increasing the intrinsic interference and consequently the degradation of the bit error rate (BER). In this work, we consider both the conventional rectangular QAM-FBMC and the so-called quincunx QAM-FBMC which uses a hexagonal lattice structure in the frequency-time plane instead of the rectangular lattice. We optimize and compare the efficiency of prototype filters with different overlapping factors for both rectangular and quincunx QAM-FBMC systems. For this, we search the filter coefficients that minimize the intrinsic interference (ISI) observed at the receiver. The simulation results show that the proposed optimization problems can improve the BER performance of both, rectangular and quincunx QAM-FBMC systems.

Keywords

• Filter-bank multicarrier
• QAM-FBMC
• HQAM-FBMC
• quincunx lattice
• prototype filter design
• wireless communication