The coefficients of digital predistortion (DPD) models are often extracted by the least square (LS) method, which has high computational complexity because of the operations of the large matrix. In this letter, a low complexity coefficient extraction method for instantaneous sample indexed magnitude-selective affine (I-MSA) model is proposed. The proposed method uses the tangent of the midpoint of the piecewise function to fit the curve. Therefore, the LS coefficient extraction only needs a small amount of data near the midpoint, rather than using all the data in the segmented region. Simulation and experimental results have confirmed that compared with the original LS method, the proposed method has similar modeling accuracy and linearization performance, but the computational complexity of coefficient extraction is greatly reduced.

中文翻译：

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瞬时样本索引幅度选择性仿射行为模型的切线逼近系数提取方法

数字预失真(DPD)模型的系数提取往往采用最小二乘法(LS)，由于矩阵运算量大，计算复杂度高。在这封信中，提出了一种用于瞬时样本索引幅度选择仿射（I-MSA）模型的低复杂度系数提取方法。所提出的方法使用分段函数中点的切线来拟合曲线。因此，LS系数提取只需要中点附近的少量数据，而不是使用分割区域内的所有数据。仿真和实验结果证实，与原LS方法相比，该方法具有相似的建模精度和线性化性能，但系数提取的计算复杂度大大降低。