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

Abstract

AbstractIn 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.