An adaptive soft clipping method for spectrum sharing OFDMA systems

Fujiwara, Toru; Tomisato, Shigeru; Hata, Masaharu; Fujii, Hiromasa; Asai, Takahiro; Okumura, Yukihiko

doi:10.1109/pimrc.2009.5450169

Cited by 1 publication

(2 citation statements)

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“…Two soft clipping CFR techniques were proposed in [5] and [6]; however, little information was provided on the spectral performances of the proposed techniques. Moreover, there has been little research done on the PAPR of the resulting signal.…”

Section: Optimized Soft Clipping Techniquementioning

confidence: 99%

See 1 more Smart Citation

Optimized Spectrum Constrained Crest Factor Reduction Technique Using Polynomials

Amiri

Helaoui

Boulejfen

et al. 2015

IEEE Trans. Commun.

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This paper proposes a new peak-to-average power ratio (PAPR) reduction technique using a polynomial soft clipping function identified through a nonlinear constrained optimization. The power efficiency optimization problem of a linearized power amplifier can be considered as the minimization of the PAPR constrained by meeting the spectral mask requirements of the signal standard. It is demonstrated that the proposed approach can reduce the PAPR from 9.9 dB to 5.5 dB while meeting the spectral mask of the WCDMA standard. To compare the results with the traditional clipping and filtering method, the 5.5 dB PAPR clipped signal using the clipping and filtering technique was compared with the soft clipped signal. With the same efficiency, the error vector magnitude (EVM) for the soft clipped signal improved from 4.5% to 1.3% using post-compensation. Later, clipping and filtering is combined with the soft clipping technique. It is shown that the combined structure can reduce the PAPR to 3.4 dB, while passing the adjacent channel power ratio and EVM requirements. The performance of the proposed method in the presence of AWGN and fading channels has been evaluated for 64QAM modulations using OFDM modulated symbols.

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Section: Optimized Soft Clipping Techniquementioning

confidence: 99%

“…However, soft clipping can be easily compensated for. Two soft clipping methods have been proposed [5,6]. Both of these approaches were established based on the Saleh PA model, which has only two parameters.…”

mentioning

confidence: 99%