一种基于QRD—RLS分数倍时延估计的方法

数字预失真技术可以有效的增大功放线性工作区间来提高功放效率。数字预失真做为自适应系统，在直接学习和间接学习架构中都试图使得进入预失真器的信号与从功放耦合的反馈信号的差值趋于最小。因此输入信号和功放反馈信号在时域上必须要严格对齐，从保证预失真器的收敛。但是由于进入预失真器的信号经过处理后，再经由DAC、射频处理链路、反馈射频链路和反馈下变频得到对应的反馈信号，使得两者间存在一定时延差。常见的延时估计法有插值估计法和基于自适应算的估计算法，文章提出的基于QRD—RLS的延时估计方法具有实现简单以及适应性好的特点。

A Fraction-Delay Estimation Method Based on QRD-RLS

Digital predistortion （DPD） technology can effectively increase power amplifier＇s linear working zone to improve Power amplifier efficiency. DPD as a self-adaption system try to minimize the error between the input signal to predistorter and the feedback signal from PA in direct learning and indirect learning struct both. The predistorter input signal and feedback signal must be aligned strictly in time domain so that the convergence of the predistorter can be assured. But there is delayed time between them due to the feedback signal take a longer path which after the predistorter process, entering the DAC,downlink analog link,feedback analog link and feedback digital-down-convert. The interpolation estimation and adaptive estimation are common estimation algorithms. Fraction delay estimation based QRD-RLS presented in this paper has features of realized easily and adapting well.