中国邮电高校学报(英文) ›› 2016, Vol. 23 ›› Issue (6): 47-52.doi: 10.1016/S1005-8885(16)60069-9

• Wireless • 上一篇    下一篇

Low sampling rate technique based frequency-domain random demodulation for broadband digital predistortion

赵景梅1,刘元安1,于翠屏1,余建国1,2   

  1. 1. 北京邮电大学
    2.
  • 收稿日期:2016-08-12 修回日期:2016-12-24 出版日期:2016-12-31 发布日期:2016-12-30
  • 通讯作者: 赵景梅 E-mail:yuanjie0405@sina.com
  • 基金资助:
    国家重点基础研究发展计划资助 (973 Program);国家863计划;国家自然基金重大科研仪器设备研制专项

Low sampling rate technique based frequency-domain random demodulation for broadband digital predistortion

  • Received:2016-08-12 Revised:2016-12-24 Online:2016-12-31 Published:2016-12-30
  • Supported by:
    National Key Basic Research Program of China (973 Program);863 Program;National Natural Science Foundation of China for the Major Equipment Development

摘要: This paper proposes a combination technique of the frequency-domain random demodulation (FRD) and the broadband digital predistorter (DPD). This technique can linearize the power amplifiers (PAs) at a low sampling rate in the feedback loop. Based on the theory of compressed sensing (CS), the FRD method preprocesses the original signal using the frequency domain sampling signal with different stages through multiple parallel channels. Then the FRD method is applied to the broadband DPD system to restrict the sampling process in the feedback loop. The proposed technique is assessed using a 30 W Class-F wideband PA driven by a 20 MHz orthogonal frequency division multiplexing (OFDM) signal, and a 40 W GaN Doherty PA driven by a 40 MHz 4-carrier long-term evolution (LTE) signal. The simulation and experimental results show that good linearization performance can be achieved at a lower sampling rate with about 24 dBc adjacent channel power ratio (ACPR) improvement by applying the proposed combination technique FRD-DPD. Furthermore, the performance of normalized mean square error (NMSE) and error vector magnitude (EVM) also has been much improved compared with the conventional technique.

关键词: power amplifiers, digital predistortion, CS, frequency-domain random demodulation

Abstract: This paper proposes a combination technique of the frequency-domain random demodulation (FRD) and the broadband digital predistorter (DPD). This technique can linearize the power amplifiers (PAs) at a low sampling rate in the feedback loop. Based on the theory of compressed sensing (CS), the FRD method preprocesses the original signal using the frequency domain sampling signal with different stages through multiple parallel channels. Then the FRD method is applied to the broadband DPD system to restrict the sampling process in the feedback loop. The proposed technique is assessed using a 30 W Class-F wideband PA driven by a 20 MHz orthogonal frequency division multiplexing (OFDM) signal, and a 40 W GaN Doherty PA driven by a 40 MHz 4-carrier long-term evolution (LTE) signal. The simulation and experimental results show that good linearization performance can be achieved at a lower sampling rate with about 24 dBc adjacent channel power ratio (ACPR) improvement by applying the proposed combination technique FRD-DPD. Furthermore, the performance of normalized mean square error (NMSE) and error vector magnitude (EVM) also has been much improved compared with the conventional technique.

Key words: power amplifiers, digital predistortion, CS, frequency-domain random demodulation

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