A novel DPSS filter optimization scheme to reduce the intrinsic interference of FBMC-QAM systems

In order to reduce the intrinsic interference of the filter bank multicarrier-quadrature amplitude modulation (FBMC-QAM) system, a novel filter optimization scheme based on discrete prolate spheroidal sequences (DPSS) is proposed. Firstly, a prototype filter function based on DPSS is designed, since the eigenvalue can be used as an indicator of the energy concentration of DPSS, so a threshold is set, and the sequence with the most concentrated energy is selected under the threshold, that is, the sequence with the eigenvalue higher than the threshold, and the prototype filter function is rewritten as a weighted sum function of multiple eigenvectors. Under the energy constraints of the filter, the relationship between the eigenvectors and the intrinsic interference function is established, and the function problem is transformed into an optimization problem for the weighted coefficients. Through the interior point method, the most suitable weight is found to obtain the minimum intrinsic interference result. Theoretical analysis and simulation results show that compared with the prototype filters such as Type1 and CaseC, the DPSS filter applying the proposed optimization algorithm can effectively suppress the intrinsic interference of the system and obtain a better bit error rate (BER) performance. © 2024 Inst. of Scientific and Technical Information of China. All rights reserved.