本发明提供一种估计方法，用以为一功率放大器之前置补偿估计一组复数因子中之复数个复数因子。针对一计算期间，一复数因子自该组复数因子中被选出。于该计算期间内，该复数因子之一估计解利用一迭代计算被产生。该迭代计算令该估计解经过一任意次数之迭代后朝向一最终解收敛。该任意次数之迭代未受该计算期间之一时间长度限制。该估计解经过该迭代计算中各次迭代后产生之一累积误差被计算出来。一收敛条件是否已成立系根据该累积误差来决定。当该收敛条件成立时，结束该估计。

To estimate complex factors for use in predistortion of a power amplifier, a complex factor is selected a set of complex factors a computation interval. A solution value is estimated for the selected complex factor during the computation interval by an iterative computation that constrains the estimated solution value towards a final solution value over an arbitrary number of iterations that is not bounded by the duration of the computation interval. A cumulative error in the estimated solution value is computed at each iteration over consecutive computation intervals. From the cumulative error, it is determined whether a convergence criterion is met and, if so, the estimating is terminated. The termination occurs independently of the solution value estimated for any one of the complex factors in the set.