摘要
针对传统的记忆多项式数字预失真方法,在对包络跟踪功率放大器线性化时遇到的问题,从电路模型的特性出发,进行了分析,根据分析结果进行数学建模,在传统方法的基础上,提出了一种新的记忆多项式建模方法,即增加了当前时刻和记忆时刻的交叉相乘项,并截断了记忆时刻的高阶非线性项.仿真的结果表明,新方法比传统的记忆多项式方法能带来更好的线性化效果,ACPR(adjacent channel power ratio)降低约4dB,NMSE(normalized mean square error)降低约2.5dB,而且系统的复杂度也有所简化.
A novel model in digital predistortion for ETPA （envelope tracking power amplifier） was proposed. By analyzing the ETPA operating mode, a new mathematical model was obtained to simulate the unique CharaCteristic of circuit. The new model was reconstructed based on the traditional MP （memory polynomial） model, by adding cross terms between different time periods and truncating the nonlinearity orders of memory terms. The simulation results show that the proposed model can provide ACPR improvement of about 4 dB and NMSE improvement of about 2.5 dB comps/red with the traditional memory polynomial model, with some reduction in system complexity as well.
基金
新一代无线通信网重大科技专项(2010ZX03007-003)
华为高校科技基金资助
关键词
功率放大器
包络跟踪
数字预失真
记忆多项式
power amplifier
envelope tracking
digital predistortion
memory polynomial
