Continuous unconstrained PSO-PTS strategy to maximize HPA energy efficiency for FBMC-OQAM systems

In filter bank multi-carrier (FBMC) with offset quadrature amplitude modulation (OQAM) systems, the major limitation of FBMC-OQAM signaling is the high peak-to-average power ratio (PAPR). High PAPR results in increased hardware complexity and is also prone to non-linear effects of high-power amplifiers (HPA). The existing HPA energy-efficient optimization strategies are constrained severely by the scarcity and heterogeneity of signal distribution in the degree of freedom. This paper theorizes the optimal FBMC-OQAM signal distribution, which has a global and steady feature and evaluates the maximal HPA efficiency-suited multi-carrier modulation (MCM) signal. This paper first proposes that the Binary Particle Swarm Optimization based Partial Transmit Sequence (BPSO-PTS) with the Input-Back Off Modulation Error Ratio (IBO-MER) scheme traces the signal distribution for maximal HPA efficiency to save supply-side energy. This paper further proposes Continuous-Unconstrained Particle Swarm Optimization based PTS(CUPSO-PTS) with IBO-MER to obtain the theoretical boundaries and drastically accelerate convergence in the continuous-unconstrained searching space. To decrease the computational complexity of MER calculation, this paper proposes the CUPSO with IBO Signal-to-Distortion Ratio (IBO-SDR), enabling it to meet more practical applications. The simulation results show that the proposed scheme outperforms conventional IBO and HPA efficiency schemes.