高功率放大器是无线通信系统中非线性失真的主要来源之一.数字基带预失真技术能有效地降低系统非线性失真,提高系统传输性能.采用Hammerstein模型作为预失真器的模型结构,通过粒子群优化算法(particle swarm algorithm,PSO)估计预失真器系数,解决了梯度算法无法直接估计Hammerstein模型系数和易陷入局部极值等问题.通过对PSO算法进行并行优化设计,使算法最大加速度比达3以上,加快了算法处理速度.仿真结果表明新算法能够有效抑制系统带外频谱再生现象,减小相邻信道功率比(ACPR)达25dB.
High power amplifier (HPA) is one of the main sources of nonlinear distortion inwireless communication systems. Digital baseband predistortion technology can effectively reducethe nonlinear distortion and improve the system transmission performance. In this paper, aparticle swarm optimization (PSO) algorithm was used directly to estimate the parameters ofHammerstein predsitorter model and to solve the local maximum problem of gradient algorithms.The predistortion algorithm was optimized into a parallel computing structure which could lead tothe maximum acceleration rate of the algorithm greater than 3. Simulation results show that theproposed algorithm can effectively suppress the spectrum regrowth outside band and reduceACPR about 25 dB.