The Digital Predistortion of the SC-FDMA Signals in LTE Uplink System
International Journal of Electronics Letters
The single-carrier frequency-division multiple access (SC-FDMA) is used in the uplink of the long-term evolution (LTE) and LTE-advanced systems because of the lower peak-to-average-power ratio (PAPR) compared with the widely used orthogonal frequency-division multiplexing (OFDM) scheme. However, the non-linearity caused by the characteristic of the radio frequency (RF) power amplifiers (PAs) is still a critical problem, and there are few researches about the linearisation for the SC-FDMA signals. The digital predistorter is widely applied by employing digital baseband distortion ahead of the amplifier to compensate for the non-linearity effects and provide efficiency enhancements for high PAs in the different communication systems. This letter presents an efficient and flexible inverse autoregressive moving-average (ARMA) model-based digital predistorter to linearise the PA distortion with memory in the LTE uplink system. The proposed digital predistortion (DPD) algorithm is for the first time applied to SC-FDMA signals and verified with a series of experimental measurements. The spectrum regrowth of SC-FDMA signals is improved by up to 12 dB from both simulation and measurement. The proposed predistorter has been shown to solve the distortion problem caused by the memory effect effectively in RF PA.
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Changwen Zhu, Xiao Li, and Fu Li. (2015). The Digital Predistortion of the SC-FDMA Signals in LTE Uplink System. International Journal of Electronics Letters, Vol. 5, Issue 1. pages 62-68.