A new signal injection method with PSO for multi-carrier predistortion

Abstract

In multi-carrier transmitters, nonlinear characteristic of power amplifiers (PAs) results in intra-band distortion and inter-band distortion. The intra-band distortion exists in most single-carrier transmitters as well, and can be removed by traditional digital predistortion (DPD) techniques. However, the inter-band distortion is rather unique for the multi-carrier linearization. A channel-selective multi-cell DPD architecture which deals with the intra-band and inter-band distortion separately is used in this paper. Furthermore, a new signal injection method with particle swarm optimization (PSO) is proposed to suppress the inter-band distortion in the paper. The injected inter-band signals are firstly reconstructed by a memory polynomial DPD, and then their amplitude and phase are fine-tuned by a PSO algorithm. Simulation results show that the method restrains inter-band distortion significantly and accelerates the convergence speed of PSO algorithm.