In this article, an exponential companding (EC) scheme, which can reduce PAPR without raising the average output power level, is proposed for universal filtered multi carrier (UFMC) signals. However, EC scheme degrades the BER performance. Therefore, an optimal nonlinear companding transform named as “modified exponential companding” (MEC), which can use two companding levels based on a threshold value, is proposed. The proposed MEC scheme shows enhanced PAPR and BER performances than EC scheme. Moreover, the MEC provides more design flexibility and freedom with an unchanged average output power level. Furthermore, a hybrid scheme is also proposed to improve PAPR performance, where clipping operation is employed on MEC signal based on an appropriate clipping threshold. Simulation results illustrate that proposed MEC scheme offers improved system performance with a net gain of 7.22 dB than conventional EC and μ‐law techniques. Besides, the proposed hybrid scheme with clipping ratio 1.3 proffers enhanced PAPR reduction of 8.85 dB and improved net gain of 7.95 dB. Also, the proposed EC, MEC, and hybrid schemes can provide lesser spectrum side‐lobe levels than μ‐law. Finally, the UFMC system with the proposed hybrid scheme is verified by employing wireless open‐access research platform (WARP) as hardware over real‐time channel.

中文翻译：

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通用滤波多载波系统最优的带削波非线性压扩变换

本文针对通用滤波多载波（UFMC）信号提出了一种指数扩展（EC）方案，该方案可以在不提高平均输出功率水平的情况下降低PAPR。但是，EC方案会降低BER性能。因此，提出了一种最优的非线性压扩变换，称为“修正指数压扩”（MEC），它可以基于阈值使用两个压扩级别。所提出的MEC方案显示出比EC方案增强的PAPR和BER性能。此外，MEC在不改变平均输出功率水平的情况下提供了更多的设计灵活性和自由度。此外，还提出了一种混合方案来改善PAPR性能，其中基于适当的限幅阈值对MEC信号进行限幅操作。μ律技术。此外，提出的限幅比为1.3的混合方案可提高PAPR降低8.85 dB，并提高净增益7.95 dB。而且，提出的EC，MEC和混合方案可以提供比μ律小的频谱旁瓣电平。最后，通过采用无线开放访问研究平台（WARP）作为实时通道上的硬件，验证了提出的混合方案的UFMC系统。