Support vector machine （SVM） is powerful to solve some problems such as nonlinear classification, function estimation and density estimation. To consider the chaotic fh （frequency hopping）-code＇s characters in ch...Support vector machine （SVM） is powerful to solve some problems such as nonlinear classification, function estimation and density estimation. To consider the chaotic fh （frequency hopping）-code＇s characters in chaotic dynamic system, the forecasting model of the support vector machine in combination with Takens＇ delay coordinate phase reconstruction of chaotic times is established and the least squares model for large-scale problems is used in local training for this model. Finally, a fh-code series generated by Logistic-Kent mapping is applied to verify the local prediction model. Simulation results show that the high accuracy and fault tolerant SVM model has an excellent performance in predicting the fh code, with a very low mean square error and a high relative coefficient.展开更多
This study proposes a novel multi-fractal spectrumbasedapproach to distinguish linear block codes from its selfsynchronousscrambled codes. Given that the linear block codeand self-synchronous scrambled linear block co...This study proposes a novel multi-fractal spectrumbasedapproach to distinguish linear block codes from its selfsynchronousscrambled codes. Given that the linear block codeand self-synchronous scrambled linear block code share the propertyof linear correlation, the existing linear correlation-basedidentification method is invalid for this case. This drawback can becircumvented by introducing a novel multi-fractal spectrum-basedmethod. Simulation results show that the new method has highrobustness and under the same conditions of bit error, the lowerthe code rate, the higher the recognition rate. Thus, the methodhas significant potential for future application in engineering.展开更多
A new segmented correlating decoder of synchronous optical CDMA using modified prime sequence codes is proposed. The performance of the proposed system is analyzed under the assumption of Poisson shot noise model for ...A new segmented correlating decoder of synchronous optical CDMA using modified prime sequence codes is proposed. The performance of the proposed system is analyzed under the assumption of Poisson shot noise model for the receiver photodetector. The decoder technique is shown to be more effective to improve the bit error probability performance than the method using an optical hard-limiter.展开更多
基本LS(link space code)码具有“零相关窗”(IFW)且被用于传统大区域同步码分多址系统(LAS-CDMA),但其零相关窗的分布是不均匀的.对基本LS码片用矩阵中克罗内克积方法重新排列,得到了一类新的LS码,从数学上证明了这类新码非周期自相关...基本LS(link space code)码具有“零相关窗”(IFW)且被用于传统大区域同步码分多址系统(LAS-CDMA),但其零相关窗的分布是不均匀的.对基本LS码片用矩阵中克罗内克积方法重新排列,得到了一类新的LS码,从数学上证明了这类新码非周期自相关函数具有均匀的IFW,以及组内码字之间的IFW也是均匀分布的.码组间的非周期互相关函数具有均匀分布的IFW,或者完美理想互补的特点.计算机仿真结果验证了新码性质的正确性.展开更多
InterRange Instrumentation Group（IRIG-B（AC））code is usually used in the shooting range test for time information transmission and systems time synchronization.According to IRIG-B（AC）code format and modulation pr...InterRange Instrumentation Group（IRIG-B（AC））code is usually used in the shooting range test for time information transmission and systems time synchronization.According to IRIG-B（AC）code format and modulation principle,this paper presents IRIG-B（AC）coding circuit design scheme based on field programmable gate array（FPGA）.The B（AC）code signal is generated by AD7245,a digital-to-analog（D/A）converter.After amplified,the signal can be used directly for system time synchronization,and the amplitude of the signal can be adjusted according to different requirements.The IRIG-B（AC）encoder designed has been verified by test.The test results show that it can output accurate time information and has higher practicality.展开更多
This article proposes a time/frequency synchronization algorithm in the multiple input multiple output(MIMO)systems,in which the perfect complete generalized complementary orthogonal loosely synchronous code groups ar...This article proposes a time/frequency synchronization algorithm in the multiple input multiple output(MIMO)systems,in which the perfect complete generalized complementary orthogonal loosely synchronous code groups are used as the synchronization sequence.The synchronization algorithm is divided into four stages:1)synchronization in time domain by signal autocorrelation;2)synchronization in frequency domain by fast Fourier transform(FFT);3)multipath dissociation using coherent detection and fine time synchronization;4)fine frequency offset estimation by phase rotation.As per the perfect complete generalized complementary orthogonal loosely synchronous code groups,the cross-correlation and out-of-phase auto-correlation for any relative shift between any two codes is always zero.This ideal property makes the time/frequency synchronization algorithm simple and efficient.The simulation results show that even in the multipath fast fading channel with low signal noise ratio(SNR),the MIMO system can get synchronized both in the time domain and frequency domain with high stability and reliability.展开更多
Security vulnerability of denial of service (DoS) in time out-medium access control (T-MAC) protocol was discussed and analysis of power consumption at each stage of T-MAC protocol was carried out. For power efficient...Security vulnerability of denial of service (DoS) in time out-medium access control (T-MAC) protocol was discussed and analysis of power consumption at each stage of T-MAC protocol was carried out. For power efficient authentication scheme which can provide reliability, efficiency, and security for a general T-MAC communication, a novel synchronization and authentication scheme using authentication masking code was proposed. Authentication data were repeated and masked by PN sequence. The simulation results show that the proposed approach can provide synchronization and authentication simultaneously for nodes in wireless sensor network (WSN). 63 bits AMC code gives above 99.97% synchronization detection and 93.98% authentication data detection probability in BER 0.031 7.展开更多
基金the National Natural Science Foundation of China(10577007)Special Fund of Anti-InterferenceTechnology in Tactical Communication Defend Lab(51434020105ZS04).
文摘Support vector machine （SVM） is powerful to solve some problems such as nonlinear classification, function estimation and density estimation. To consider the chaotic fh （frequency hopping）-code＇s characters in chaotic dynamic system, the forecasting model of the support vector machine in combination with Takens＇ delay coordinate phase reconstruction of chaotic times is established and the least squares model for large-scale problems is used in local training for this model. Finally, a fh-code series generated by Logistic-Kent mapping is applied to verify the local prediction model. Simulation results show that the high accuracy and fault tolerant SVM model has an excellent performance in predicting the fh code, with a very low mean square error and a high relative coefficient.
基金supported by the National Natural Science Foundation of China(61171170) the Natural Science Foundation of Anhui Province(1408085QF115)
文摘This study proposes a novel multi-fractal spectrumbasedapproach to distinguish linear block codes from its selfsynchronousscrambled codes. Given that the linear block codeand self-synchronous scrambled linear block code share the propertyof linear correlation, the existing linear correlation-basedidentification method is invalid for this case. This drawback can becircumvented by introducing a novel multi-fractal spectrum-basedmethod. Simulation results show that the new method has highrobustness and under the same conditions of bit error, the lowerthe code rate, the higher the recognition rate. Thus, the methodhas significant potential for future application in engineering.
文摘A new segmented correlating decoder of synchronous optical CDMA using modified prime sequence codes is proposed. The performance of the proposed system is analyzed under the assumption of Poisson shot noise model for the receiver photodetector. The decoder technique is shown to be more effective to improve the bit error probability performance than the method using an optical hard-limiter.
基金Acknowledgments： This work was supported by the National Natural Science Foundation of China （No. 60773012） and Postdoctoral Science Foundation of China （No. 20070420184）, and in part by Joint Project KOSEF/NSFC Korea Research Foundation （No. KRF-D-2007-52 1-D00330）, and ETRI, Korea.
文摘基本LS(link space code)码具有“零相关窗”(IFW)且被用于传统大区域同步码分多址系统(LAS-CDMA),但其零相关窗的分布是不均匀的.对基本LS码片用矩阵中克罗内克积方法重新排列,得到了一类新的LS码,从数学上证明了这类新码非周期自相关函数具有均匀的IFW,以及组内码字之间的IFW也是均匀分布的.码组间的非周期互相关函数具有均匀分布的IFW,或者完美理想互补的特点.计算机仿真结果验证了新码性质的正确性.
基金The 10th Postgraduate Science and Technology Fund of North University of China(No.20131020)
文摘InterRange Instrumentation Group（IRIG-B（AC））code is usually used in the shooting range test for time information transmission and systems time synchronization.According to IRIG-B（AC）code format and modulation principle,this paper presents IRIG-B（AC）coding circuit design scheme based on field programmable gate array（FPGA）.The B（AC）code signal is generated by AD7245,a digital-to-analog（D/A）converter.After amplified,the signal can be used directly for system time synchronization,and the amplitude of the signal can be adjusted according to different requirements.The IRIG-B（AC）encoder designed has been verified by test.The test results show that it can output accurate time information and has higher practicality.
基金supported by the National Natural Science Foundation of China(90604035)
文摘This article proposes a time/frequency synchronization algorithm in the multiple input multiple output(MIMO)systems,in which the perfect complete generalized complementary orthogonal loosely synchronous code groups are used as the synchronization sequence.The synchronization algorithm is divided into four stages:1)synchronization in time domain by signal autocorrelation;2)synchronization in frequency domain by fast Fourier transform(FFT);3)multipath dissociation using coherent detection and fine time synchronization;4)fine frequency offset estimation by phase rotation.As per the perfect complete generalized complementary orthogonal loosely synchronous code groups,the cross-correlation and out-of-phase auto-correlation for any relative shift between any two codes is always zero.This ideal property makes the time/frequency synchronization algorithm simple and efficient.The simulation results show that even in the multipath fast fading channel with low signal noise ratio(SNR),the MIMO system can get synchronized both in the time domain and frequency domain with high stability and reliability.
文摘Security vulnerability of denial of service (DoS) in time out-medium access control (T-MAC) protocol was discussed and analysis of power consumption at each stage of T-MAC protocol was carried out. For power efficient authentication scheme which can provide reliability, efficiency, and security for a general T-MAC communication, a novel synchronization and authentication scheme using authentication masking code was proposed. Authentication data were repeated and masked by PN sequence. The simulation results show that the proposed approach can provide synchronization and authentication simultaneously for nodes in wireless sensor network (WSN). 63 bits AMC code gives above 99.97% synchronization detection and 93.98% authentication data detection probability in BER 0.031 7.
