CAJ | 학술논문

过高的峰均比（PAPR,peak-to-average power ratio）是正交频分复用技术（OFDM,Orthogonal Frequency-Di-vision Multiplexing）的一个主要缺陷。PAPR抑制技术的应用可以最大限度地减小的非线性失真,提高功率放大器（HPA,High Power Amplifier）的效率。在OFDM系统中,随着载波数的增加,PAPR性能会变差。本文使用了一种削波滤波（CF,Clipping＆Filtering）与星座图扩展（ACE,Active Constellation Extension）相结合的方法,可以在无数据率损失的情况下减小PAPR。在本方案中,计算出一个标准OFDM信号的PAPR数据作为参考。先对信号进行CF操作,把信号的PAPR值限制到很低的幅度,再用星座图扩展的方法恢复MER指标,就可以让信号进入非线性功放之前降低PAPR,并保证带外噪声符合发射机的要求。最后,把经过处理的OFDM信号和原始OFDM信号同时送入不同功率回退（IBO）参数的HPA进行了对比。实验结果表明,把信号送入功率回退为7dB的HPA,经过PAPR抑制算法处理的信号带肩比可以改善2dB以上,MER改善1dB以上。
과고적봉균비（PAPR,peak-to-average power ratio）시정교빈분복용기술（OFDM,Orthogonal Frequency-Di-vision Multiplexing）적일개주요결함。PAPR억제기술적응용가이최대한도지감소적비선성실진,제고공솔방대기（HPA,High Power Amplifier）적효솔。재OFDM계통중,수착재파수적증가,PAPR성능회변차。본문사용료일충삭파려파（CF,Clipping＆Filtering）여성좌도확전（ACE,Active Constellation Extension）상결합적방법,가이재무수거솔손실적정황하감소PAPR。재본방안중,계산출일개표준OFDM신호적PAPR수거작위삼고。선대신호진행CF조작,파신호적PAPR치한제도흔저적폭도,재용성좌도확전적방법회복MER지표,취가이양신호진입비선성공방지전강저PAPR,병보증대외조성부합발사궤적요구。최후,파경과처리적OFDM신호화원시OFDM신호동시송입불동공솔회퇴（IBO）삼수적HPA진행료대비。실험결과표명,파신호송입공솔회퇴위7dB적HPA,경과PAPR억제산법처리적신호대견비가이개선2dB이상,MER개선1dB이상。
High peak-to-average power ratio（PAPR） is one of the major drawbacks of Orthogonal Frequency-Division Multiplexing（OFDM）.PAPR reduction can be utilized to decrease the nonlinear distortion and to improve the power efficiency of the nonlinear HPA（high power amplifier）.In an OFDM system,as the frame size increases,the PAPR probability performance will get worse.In this paper,a novel approach,clipping-and-filtering（CF） scheme with the proposed active constellation extension（ACE） algorithm is presented to reduce the PAPR without any date rate loss.In our proposal,the target PAPR is firstly set and the level clipping is fundamentally used.ACE algorithm is then applied to improve be MER performance characteristics for the OFDM system.Finally,we analyze the PAPR reduction effects on HPA and show the performance variation in the HPA nonlinear characteristic according to change of IBO（input back off） value.By the results of proposed method,we can confirm that the proposed combined system shows better MER and shoulder level performance even in when the effect of HPA is considered.