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作 者:胡峰[1] 蔡超时[1] 刘昌银[1] 方伟伟[1]
机构地区:[1]中国传媒大学,北京100024
出 处:《电视技术》2014年第9期170-174,共5页Video Engineering
摘 要:高峰均功率比一直是掣肘OFDM系统性能的最大障碍。为了更精确地评估峰均比抑制对功放失真的影响,提出了最优CCDF(OCCDF)迭代收敛准则。新准则考虑放大器中每个子载波的失真,限定MER条件下得到尽可能低的放大器输入功率回退(IBO),获得最高功放效率所匹配的OFDM整体信号分布。基于此,在CMMB系统中给出了一种高效的时域削波结合星座图扩展(ACE)的峰均比抑制技术。采用OCCDF迭代峰均比抑制方案实验结果:MER=40 dB条件下,基于ACE峰均比抑制的OFDM系统相比抑制前获得了3.05 dB的功放IBO性能改善。对应到功率放大器的性能改善:功放效率提升了15.74%,总功耗和管耗分别降低了22.2%和40.19%。Orthogonal frequency division multiplexing (OFDM) is limited mainly by its high peak-to-average power ratio (PAPR). In this work, an optimal CCDF (OCCDF) convergence criterion is proposed since it can predict high-power amplifier (HPA) power distortion more accurately. In this e- valuation criterion, an analytical approach to calculate the non-linear distortions of each sub-carrier is proposed, to achieve a minimized input power back off (IBO) of HPA with more suited OFDM signals for a MER limited. Based on this evaluation platform, a clipping with active constellation exten- sion (ACE) in CMMB system is simulated. It finally gives the performance results obtained with the proposed evaluation platform: The implementation of OCCDF method is shown to offer a 3.05 dB IBO performance gain (at a MER of 40 dB), an improvement of 15.74% in HPA efficiency, a reduction of 22.2% and 40.19% in the total power and power dissipation, respectively when compared to the traditional OFDM transmission without reducing PAPR.
关 键 词:正交频分复用 峰均比抑制 互补累积分布函数 最优互补累积分布 迭代收敛准则 星座图扩展
分 类 号:TN929.5[电子电信—通信与信息系统]
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