基于循环自相关的NC-OFDM信号参数的盲估计
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摘要
在认知无线电(CR)环境中,频率资源不足的问题越来越严重,而非连续正交频分复用(NC-OFDM)能够工作在非连续的频谱环境。针对NC-OFDM信号的参数估计问题,提出一种循环自相关的方法。该方法首先分析循环平稳信号特点,然后根据NC-OFDM信号的循环自相关,在循环频率α以及时延τ切面图具有离散谱线特征进行参数估计,最后对NC-OFDM信号的循环自相关进行数值仿真。仿真结果表明在低信噪比下,能有效估计NC-OFDM信号的参数及识别零前缀的正交频分复用信号(ZP-OFDM),且实验证明关闭近90%的子载波数目都能够实现NC-OFDM信号的参数的盲估计。
In the cognitive radio(CR) environment,the problem of insufficient frequency resources gets severe,however noncontinuous orthogonal frequency division multiplexing(NC-OFDM) can work in the non-continuous spectral environment. This paper proposed cyclic autocorrelation method to deal with the important problem of parameter estimation of NC-OFDM signals.Firstly,it analyzed the characteristics of cyclostationary of signals. Then according to the cyclic autocorrelation of the NCOFDM signal,it estimated the parameters with the characteristics of the discrete spectral lines in the cyclic frequency α and the time delay τ cutaway. Finally,this paper simulated the cyclic autocorrelation of the NC-OFDM signals. The simulation results show that the parameters of NC-OFDM signal can be effectively estimated and recognized zero-prefix orthogonal frequency division multiplexing signals(ZP-OFDM) at low signal-to-noise ratio,and the experiments show that close to 90% of the number of subcarriers,can achieve NC-OFDM signals parameter blind estimation.
In the cognitive radio(CR) environment,the problem of insufficient frequency resources gets severe,however noncontinuous orthogonal frequency division multiplexing(NC-OFDM) can work in the non-continuous spectral environment. This paper proposed cyclic autocorrelation method to deal with the important problem of parameter estimation of NC-OFDM signals.Firstly,it analyzed the characteristics of cyclostationary of signals. Then according to the cyclic autocorrelation of the NCOFDM signal,it estimated the parameters with the characteristics of the discrete spectral lines in the cyclic frequency α and the time delay τ cutaway. Finally,this paper simulated the cyclic autocorrelation of the NC-OFDM signals. The simulation results show that the parameters of NC-OFDM signal can be effectively estimated and recognized zero-prefix orthogonal frequency division multiplexing signals(ZP-OFDM) at low signal-to-noise ratio,and the experiments show that close to 90% of the number of subcarriers,can achieve NC-OFDM signals parameter blind estimation.
引文
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[9]陈奎,黄为勇,田传耕.基于Matrix Pencil的OFDM信号的TOA/AOA定位[J].计算机应用研究,2013,30(2):534-536,540.(Chen Kui,Huang Weiyong,Tian Chuangeng.Matrix Pencil joint TOA/AOA positioning algorithm for OFDM[J].Application Research of Computers,2013,30(2):534-536,540.)
[10]蒋清平,杨士中,张天骐.OFDM信号循环谱分析及参数估计[J].计算机应用研究,2010,27(3):1133-1135.(Jiang Qingping,Yang Shizhong,Zhang Tianqi.Cyclic spectrum analysis and parameters estimation of OFDM signals[J].Application Research of Computers,2010,27(3):1133-1135.)
[11]蒋清平,杨士中,张天骐.OFDM信号循环自相关分析及参数估计[J].华中科技大学学报:自然科学报,2010,38(2):118-121.(Jiang Qingping,Yang Shizhong,Zhang Tianqi.Cyclic autocorrelation analysis and parameter estimation of OFDM signals[J].Journal of Huazhong University of Science and Technology:Natural Science,2010,38(2):118-121.)
[12]王玉娥,张天骐,白娟,等.基于循环自相关的OFDM调制识别方法[J].电视技术,2012,36(5):44-48.(Wang Yu’e,Zhang Tianqi,Bai Juan,et al.Recognition of OFDM signals based on cyclic autocorrelation[J].Video Engineering,2012,36(5):44-48.)
[13]郑航,郭建新,周东旭.NC-OFDM多种群自适应免疫优化子载波分配算法[J].空军工程大学学报:自然科学报,2015,16(3):77-81.(Zheng Hang,Guo Jianxin,Zhou Dongxu.Multi-colony adaptive immune optimization based subcarrier allocation algorithm in NC-OFDM[J].Journal of Air Force Engineering University:Natural Science,2015,16(3):77-81.)
[2]何雪云,宋荣芳,周克琴.认知无线电NC-OFDM系统中基于压缩感知的信道估计新方法[J].通信学报,2011,32(11):85-94.(He Xueyun,Song Rongfang,Zhou Keqin.Compressive sensing based channel estimation for NC-OFDM systems in cognitive radio context[J].Journal on Communications,2011,32(11):85-94.)
[3]韩英华,汪晋宽,赵强.基于交叉熵的NC-OFDM系统最优导频序列设计算法[J].中国科技论文,2015,10(2):134-138.(Han Yinghua,Wang Jinkuan,Zhao Qiang.Optimal pilot sequence design alogorithm for NC-OFDM system based on cross entropy[J].China Sciencepaper,2015,10(2):134-138.)
[4]孙慧,杨守义,穆晓敏.NC-OFDM系统导频设计的离散粒子群算法[J].电子技术应用,2014,40(7):99-102.(Sun Hui,Yang Shouyi,Mu Xiaomin.Pilot design for NC-OFDM system based on discrete particle swarm optimization[J].Application of Electronic Technique,2014,40(7):99-102.)
[5]周东旭,贾月岭,郭建新.NC-OFDM中改进的子载波预留PAPR抑制算法[J].计算机工程,2015,41(10):10-13,19.(Zhou Dongxu,Jia Yueling,Guo Jianxin.Improved tone reservation PARRsuppression algorithm in NC-OFDM[J].Computer Engineering,2015,41(10):10-13,19.)
[6]Bolcskei H.Blind estimation of symbol timing and carrier frequency offset in wireless OFDM systems[J].IEEE Trans on Communications,2001,49(6):998-999.
[7]Jang I G,Piao Z Y,Dong Z H,et al.Low-power FFT design for NC-OFDM in cognitive radio systems[C]//Proc of IEEE International Symposium on Circuits and Systems.Piscataway,NJ:IEEE Press,2011:2499-2452.
[8]Kryszkiewicz P,Bogucka H.In-band-interference robust synchronization algorithm for an NC-OFDM system[J].IEEE Trans on Communications,2016,64(5):2143-2154.
[9]陈奎,黄为勇,田传耕.基于Matrix Pencil的OFDM信号的TOA/AOA定位[J].计算机应用研究,2013,30(2):534-536,540.(Chen Kui,Huang Weiyong,Tian Chuangeng.Matrix Pencil joint TOA/AOA positioning algorithm for OFDM[J].Application Research of Computers,2013,30(2):534-536,540.)
[10]蒋清平,杨士中,张天骐.OFDM信号循环谱分析及参数估计[J].计算机应用研究,2010,27(3):1133-1135.(Jiang Qingping,Yang Shizhong,Zhang Tianqi.Cyclic spectrum analysis and parameters estimation of OFDM signals[J].Application Research of Computers,2010,27(3):1133-1135.)
[11]蒋清平,杨士中,张天骐.OFDM信号循环自相关分析及参数估计[J].华中科技大学学报:自然科学报,2010,38(2):118-121.(Jiang Qingping,Yang Shizhong,Zhang Tianqi.Cyclic autocorrelation analysis and parameter estimation of OFDM signals[J].Journal of Huazhong University of Science and Technology:Natural Science,2010,38(2):118-121.)
[12]王玉娥,张天骐,白娟,等.基于循环自相关的OFDM调制识别方法[J].电视技术,2012,36(5):44-48.(Wang Yu’e,Zhang Tianqi,Bai Juan,et al.Recognition of OFDM signals based on cyclic autocorrelation[J].Video Engineering,2012,36(5):44-48.)
[13]郑航,郭建新,周东旭.NC-OFDM多种群自适应免疫优化子载波分配算法[J].空军工程大学学报:自然科学报,2015,16(3):77-81.(Zheng Hang,Guo Jianxin,Zhou Dongxu.Multi-colony adaptive immune optimization based subcarrier allocation algorithm in NC-OFDM[J].Journal of Air Force Engineering University:Natural Science,2015,16(3):77-81.)