Ahmed Serien, Ahmed Majid, Bensmida Souheil, Hammi Oualid
Department of Electrical Engineering, College of Engineering, American University of Sharjah, Sharjah P.O. Box 26666, United Arab Emirates.
Institute of Sensors, Signals and Systems, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburg EH14 4AS, UK.
Sensors (Basel). 2024 May 27;24(11):3439. doi: 10.3390/s24113439.
The feasibility of implementing digital predistortion for next-generation wireless communication is faced with a dilemma due to the ever-increasing demand for faster data rates. This causes the utilized bandwidth to increase significantly, as seen in the 5G NR standard in which bandwidths as high as 400 MHz are utilized. Hence, the development of new predistortion techniques in which the forward and feedback paths operate at lower sampling rates is of utmost importance to realize efficient and practical predistortion solutions. In this work, a novel predistortion technique is presented by which the predistortion is divided between the digital and analog domains. The predistorter is composed of a memoryless AM/AM gain function that is implementable in the analog domain, and a nonlinear model with memory effects in the digital domain to relax the sampling rate requirements on both the forward and feedback paths. Experimental validation was carried out with a 20 MHz and a 40 MHz 5G signal, and the results indicate minimal linearization degradation with a sampling rate reduction of 50% and 30%, respectively. This sampling rate reduction is concurrently applied in the digital-to-analog converter of the forward path and the analog-to-digital converter of the feedback path.
由于对更快数据速率的需求不断增加，下一代无线通信中实现数字预失真的可行性面临两难境地。这导致所使用的带宽显著增加，如在5G NR标准中，高达400 MHz的带宽被使用。因此，开发前向和反馈路径以较低采样率运行的新预失真技术对于实现高效且实用的预失真解决方案至关重要。在这项工作中，提出了一种新颖的预失真技术，通过该技术将预失真划分在数字和模拟域之间。预失真器由一个可在模拟域实现的无记忆AM/AM增益函数以及一个在数字域具有记忆效应的非线性模型组成，以放宽对前向和反馈路径的采样率要求。使用20 MHz和40 MHz的5G信号进行了实验验证，结果表明分别将采样率降低50%和30%时，线性化性能的下降最小。这种采样率降低同时应用于前向路径的数模转换器和反馈路径的模数转换器。
