一种OFDM信号峰均比抑制算法设计
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摘要
针对移动通信系统中OFDM信号峰均比抑制算法实现复杂度高等问题,提出一种低复杂度的迭代限幅滤波峰均比抑制算法。算法首先根据功率门限P0与限幅因子α对OFDM信号的实部与虚部进行限幅处理,然后将限幅处理后的信号变换到频域进行滤波和星座扩展,最后将频域信号变换到时域,完成一次迭代限幅滤波处理。通过适当选择限幅因子α,算法仅需加法运算即可实现限幅处理。在迭代运算中,算法采用高于采样率的工作时钟复用FFT/IFFT变换单元,减少了发射机中峰均比抑制的资源消耗。仿真结果表明,所提出的算法在有效降低实现复杂度的同时,保持了较好的峰均比抑制和误比特率性能。
Aiming at the high implementation complexity of Peak-to-Average Power Ratio( PAPR) suppression methods for OFDM signals in the mobile communication system,an iterative clipping and filtering method with low complexity for PAPR suppression is proposed. Firstly,we suppress the amplitudes of OFDM signals' real parts and imaginary parts according to the power threshold P0 and clipping factor α. Then we convert the clipped signals in time domain into signals in frequency domain for next frequency filtering and constellation extension. Finally we convert the signals in frequency domain back to signals in time domain. Now one iterative step of clipping and filtering ends. This method can suppress the amplitudes of OFDM signals only with summation by selecting the appropriate clipping factor α. And in the iterative operations,this method can reduce the implementation resources in the transmitter by multiplexing the FFT / IFFT transform module with a working clock higher than the sampling frequency. Simulation results validate that the proposed method can effectively reduce the implementation complexity,meanwhile,it keeps the good PAPR suppression and BER performances.
Aiming at the high implementation complexity of Peak-to-Average Power Ratio( PAPR) suppression methods for OFDM signals in the mobile communication system,an iterative clipping and filtering method with low complexity for PAPR suppression is proposed. Firstly,we suppress the amplitudes of OFDM signals' real parts and imaginary parts according to the power threshold P0 and clipping factor α. Then we convert the clipped signals in time domain into signals in frequency domain for next frequency filtering and constellation extension. Finally we convert the signals in frequency domain back to signals in time domain. Now one iterative step of clipping and filtering ends. This method can suppress the amplitudes of OFDM signals only with summation by selecting the appropriate clipping factor α. And in the iterative operations,this method can reduce the implementation resources in the transmitter by multiplexing the FFT / IFFT transform module with a working clock higher than the sampling frequency. Simulation results validate that the proposed method can effectively reduce the implementation complexity,meanwhile,it keeps the good PAPR suppression and BER performances.
引文
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[2]Zhu X D,Pan W S,Li H,et al.Simplified Approach to Optimized Iterative Clipping and Filtering for PAPR Reduction of OFDM Signals[J].IEEE Transactions on Communications,2013,61(5):1891~1901.
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[4]Wang Y,Ge J H,Wang L,et al.Nonlinear Companding Transform for Reduction of Peak-to-Average Power Ratio in OFDM Systems[J].IEEE Transactions on Broadcasting,2013,59(2):369~375.
[5]Wang L Q,Tellambura C.A Simplified Clipping and Filtering Technique for PAR Reduction in OFDM Systems[J].IEEE Signal Processing Letters,2005,12(6):453~456.
[6]Hunziker T,Bernhard U P.Evaluation of Coding and Modulation Schemes Based on Golay Complementary Sequences for Efficient OFDM Transmission[C]//IEEE Vehicular Technology Conference,1998:1631~1635.
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[8]Xiao Y,Lei X,et al.A Class of Low Complexity PTS Techniques for PAPR Reduction in OFDM Systems[J].IEEE Signal Processing Letters,2007,14(10):680~683.
[9]马云思,周三文,闫朝星,等.无人机测控中OFDM发射机的设计与实现[J].遥测遥控,2015,36(4):45~50.Ma Yunsi,Zhou Sanwen,Yan Chaoxing,et al.Design and Implementation of OFDM Transmitter in UAV TT&C System[J].Journal of Telemetry,Tracking and Command,2015,36(4):45~50.
[10]Wang Y C,Luo Z Q.Optimized Iterative Clipping and Filtering for PAPR Reduction of OFDM Signals[J].IEEE Transactions on Communications,2011,58(1):33~37.
[11]Thompson S C,Proakis J G,Zeidler J R.The Effectiveness of Signal Clipping for PAPR and Total Degradation Reduction in OFDM Systems[C]//IEEE Global Telecommunications Conference,2005:2807~2811.
[2]Zhu X D,Pan W S,Li H,et al.Simplified Approach to Optimized Iterative Clipping and Filtering for PAPR Reduction of OFDM Signals[J].IEEE Transactions on Communications,2013,61(5):1891~1901.
[3]Saeedi H,Sharif M,Marvasti F.Clipping Noise Cancellation in OFDM Systems Using Oversampled Signal Reconstruction[J].IEEE Communication Letters,2002,6(2):73~75.
[4]Wang Y,Ge J H,Wang L,et al.Nonlinear Companding Transform for Reduction of Peak-to-Average Power Ratio in OFDM Systems[J].IEEE Transactions on Broadcasting,2013,59(2):369~375.
[5]Wang L Q,Tellambura C.A Simplified Clipping and Filtering Technique for PAR Reduction in OFDM Systems[J].IEEE Signal Processing Letters,2005,12(6):453~456.
[6]Hunziker T,Bernhard U P.Evaluation of Coding and Modulation Schemes Based on Golay Complementary Sequences for Efficient OFDM Transmission[C]//IEEE Vehicular Technology Conference,1998:1631~1635.
[7]Breiling H,Muller-weinfurtner S H,et al.SLM Peak-power Reduction without Explicit Side Information[J].IEEE Communications Letters,2001,5(6):239~241.
[8]Xiao Y,Lei X,et al.A Class of Low Complexity PTS Techniques for PAPR Reduction in OFDM Systems[J].IEEE Signal Processing Letters,2007,14(10):680~683.
[9]马云思,周三文,闫朝星,等.无人机测控中OFDM发射机的设计与实现[J].遥测遥控,2015,36(4):45~50.Ma Yunsi,Zhou Sanwen,Yan Chaoxing,et al.Design and Implementation of OFDM Transmitter in UAV TT&C System[J].Journal of Telemetry,Tracking and Command,2015,36(4):45~50.
[10]Wang Y C,Luo Z Q.Optimized Iterative Clipping and Filtering for PAPR Reduction of OFDM Signals[J].IEEE Transactions on Communications,2011,58(1):33~37.
[11]Thompson S C,Proakis J G,Zeidler J R.The Effectiveness of Signal Clipping for PAPR and Total Degradation Reduction in OFDM Systems[C]//IEEE Global Telecommunications Conference,2005:2807~2811.