OFDM系統(tǒng)中限幅非線性失真迭代對消法性能分析
Analysis of the Performance of Iterative Estimation and Cancellation of Clipping Distortion in OFDM
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摘要: 限幅技術(shù)常用于正交頻分復(fù)用系統(tǒng)中以抑制高峰值平均功率比,為抑制限幅造成的帶內(nèi)失真和帶外輻射,可以在接收端進行限幅噪聲的迭代估計和對消。該文提出對限幅帶來的非線性失真進行迭代估計和對消的效果要比僅對限幅噪聲進行估計對消好。前者在理想情況下能完全恢復(fù)出發(fā)端未限幅前的信號,但后者將始終受到由限幅帶來的信號衰減的影響。理論分析和仿真結(jié)果驗證了該結(jié)論及性能,同時數(shù)字結(jié)果表明,該算法能有效改進系統(tǒng)性能。在歸一化限幅門限為1.2時,只通過一次迭代就能提高2dB。
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關(guān)鍵詞:
- 正交頻分復(fù)用; 峰值平均功率比; 限幅; 迭代估計和對消
Abstract: Clipping is usually applied to decrease the high peak-to-average power ratio caused by OFDM with interference both inside and outside the signal bandwidth. To resolve this problem, an iterative estimation and cancellation of clipping non-linear distortion scheme is proposed. This paper presents that the performance of estimation and cancellation of clipping non-linear is better than that of clipping noise. The method of iterative estimation and cancellation of clipping non-linear distortion can resume the signal before clipping perfectly with the ideal a priori information. However, if receiver only estimate and cancel the clipping noise the signal will still be influenced by the attenuation caused by clipping. Analysis and simulation results prove the conclusion. And it is shown by numerical simulation results that system performance can be improved evidently. When the clipping threshold is 1.2, the performance is improved about 2 dB with only one iterative estimation and cancellation. -
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