A generalized memory polynomial model for digital predistortion of RF power amplifiers
A generalized memory polynomial model for digital predistortion of RF power amplifiers
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DOI：
10.1109/tsp.2006.879264
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发表时间：
2006-10-01
影响因子：
5.4
通讯作者：
Pastalan, John
中科院分区：
文献类型：
--
作者：
Morgan, Dennis R.;Ma, Zhengxiang;Pastalan, John
使用宽带信号运行的传统射频 (RF) 功率放大器，例如通用移动电信系统 (UNITS) 中的宽带码分多址 (WCDMA)，必须从其峰值功率电平大幅回退，以控制带外杂散发射，也称为“频谱再生”。因此，与相同功率输出相比，使这些放大器适应宽带操作需要更大的尺寸和更高的成本。另一种广受欢迎的解决方案是在放大器之前采用数字基带预失真来补偿非线性效应，从而使其能够更接近其最大输出功率，同时保持较低的频谱再生。该技术的最新改进包括预失真模型中的记忆效应，这随着带宽的增加而变得至关重要。在本文中，我们将一般的 Volterra 表示与经典的 Wiener、Hammerstein、Wiener-Hammerstein 和并行 Wiener 结构联系起来，并继续描述一些基于记忆多项式的最先进的预失真模型。然后，我们提出了一种新的广义内存多项式，该多项式实现了迄今为止的最佳性能，如本文中使用实际 30 W、2 GHz 功率放大器从测试台获得的实验结果所证明的那样。
Conventional radio-frequency (RF) power amplifiers operating with wideband signals, such as wideband code-division multiple access (WCDMA) in the Universal Mobile Telecommunications System (UNITS) must be backed off considerably from their peak power level in order to control out-of-band spurious emissions, also known as "spectral regrowth." Adapting these amplifiers to wideband operation therefore entails larger size and higher cost than would otherwise be required for the same power output. An alternative solution, which is gaining widespread popularity, is to employ digital baseband predistortion ahead of the amplifier to compensate for the nonlinearity effects, hence allowing it to run closer to its maximum output power while maintaining low spectral regrowth. Recent improvements to the technique have included memory effects in the predistortion model, which are essential as the bandwidth increases. In this paper, we relate the general Volterra representation to the classical Wiener, Hammerstein, Wiener-Hammerstein, and parallel Wiener structures, and go on to describe some state-of-the-art predistortion models based on memory polynomials. We then propose a new generalized memory polynomial that achieves the best performance to date, as demonstrated herein with experimental results obtained from a testbed using an actual 30-W, 2-GHz power amplifier.