Enhancing the security of the wireless communication is necessary to guarantee the reliable of the data transmission, due to the broadcast nature of wireless channels. In this paper, we provide a novel technology refe...Enhancing the security of the wireless communication is necessary to guarantee the reliable of the data transmission, due to the broadcast nature of wireless channels. In this paper, we provide a novel technology referred to as doubly multiple parameters weighted fractional Fourier transform(DMWFRFT), which can strengthen the physical layer security of wireless communication. This paper introduces the concept of DM-WFRFT based on multiple parameters WFRFT(MP-WFRFT), and then presents its four properties. Based on these properties, the parameters decryption probability is analyzed in terms of the number of parameters. The number of parameters for DM-WFRFT is more than that of the MP-WFRFT,which indicates that the proposed scheme can further strengthen the the physical layer security. Lastly, some numerical simulations are carried out to illustrate that the efficiency of proposed DM-WFRFT is related to preventing eavesdropping, and the effect of parameters variety on the system performance is associated with the bit error ratio(BER).展开更多
Recently,a weighted fractional Fourier transform(WFRFT)based hybrid carrier(HC)system has been proposed,which can converge single-carrier(SC)and multi-carrier(MC)systems.The cost and power dissipation of analog compon...Recently,a weighted fractional Fourier transform(WFRFT)based hybrid carrier(HC)system has been proposed,which can converge single-carrier(SC)and multi-carrier(MC)systems.The cost and power dissipation of analog components often dominate in practical HC systems.Therefore,in this paper,we analyze the baseband HC signal characteristics,including average signal power,power spectral density(PSD),probability density function(PDF),peak-to-average power ratio(PAPR),and complementary cumulative distribution function(CCDF),using a continuous-time HC signal approximation method.Through theoretical analysis and simulation validation,it is proved that the approximation method does not change the average signal power,bandwidth and out-of-band emission(OOBE).The theoretical PDF expression of HC signal with the approximation method is then proposed.Furt her more,the PDF can also explain why the PAPR of baseband continuous-time HC signal is higher than that of discrete-time HC signal.The PAPR performance and the power amplifier(PA)efficiency of HC systems in different conditions are analyzed.Through the PDF analysis of HC signal envelope and the numerical computations of PAPR.it is shown that the approximation method can offer a precise characteristic description for HC signal,which can help to improve the system PAPR performance and the PA efficiency.展开更多
Directional modulation(DM)is one of the most promising secure communication techniques.However,when the eavesdropper is co-located with the legitimate receiver,the conventional DM has the disadvantages of weak anti-sc...Directional modulation(DM)is one of the most promising secure communication techniques.However,when the eavesdropper is co-located with the legitimate receiver,the conventional DM has the disadvantages of weak anti-scanning capability,anti-deciphering capability,and low secrecy rate.In response to these problems,we propose a twodimensional multi-term weighted fractional Fourier transform aided DM scheme,in which the legitimate receiver and the transmitter use different transform terms and transform orders to encrypt and decrypt the confidential information.In order to further lower the probability of being deciphered by an eavesdropper,we use the subblock partition method to convert the one-dimensional modulated signal vector into a twodimensional signal matrix,increasing the confusion of the useful information.Numerical results demonstrate that the proposed DM scheme not only provides stronger anti-deciphering and anti-scanning capabilities but also improves the secrecy rate performance of the system.展开更多
The fractional Fourier transform （FRFT） has multiplicity, which is intrinsic in fractional operator. A new source for the multiplicity of the weight-type fractional Fourier transform （WFRFT） is proposed, which can...The fractional Fourier transform （FRFT） has multiplicity, which is intrinsic in fractional operator. A new source for the multiplicity of the weight-type fractional Fourier transform （WFRFT） is proposed, which can generalize the weight coefficients of WFRFT to contain two vector parameters m,n ∈ Z^M . Therefore a generalized fractional Fourier transform can be defined, which is denoted by the multiple-parameter fractional Fourier transform （MPFRFT）. It enlarges the multiplicity of the FRFT, which not only includes the conventional FRFT and general multi-fractional Fourier transform as special cases, but also introduces new fractional Fourier transforms. It provides a unified framework for the FRFT, and the method is also available for fractionalizing other linear operators. In addition, numerical simulations of the MPFRFT on the Hermite-Gaussian and rectangular functions have been performed as a simple application of MPFRFT to signal processing.展开更多
文摘Enhancing the security of the wireless communication is necessary to guarantee the reliable of the data transmission, due to the broadcast nature of wireless channels. In this paper, we provide a novel technology referred to as doubly multiple parameters weighted fractional Fourier transform(DMWFRFT), which can strengthen the physical layer security of wireless communication. This paper introduces the concept of DM-WFRFT based on multiple parameters WFRFT(MP-WFRFT), and then presents its four properties. Based on these properties, the parameters decryption probability is analyzed in terms of the number of parameters. The number of parameters for DM-WFRFT is more than that of the MP-WFRFT,which indicates that the proposed scheme can further strengthen the the physical layer security. Lastly, some numerical simulations are carried out to illustrate that the efficiency of proposed DM-WFRFT is related to preventing eavesdropping, and the effect of parameters variety on the system performance is associated with the bit error ratio(BER).
基金the National Natural Science Foundation of China(No.61671179)the National Basic Research Program of China(No.2013CB329003)the Funding of Science and Technology on Communication Networks Laboratory。
文摘Recently,a weighted fractional Fourier transform(WFRFT)based hybrid carrier(HC)system has been proposed,which can converge single-carrier(SC)and multi-carrier(MC)systems.The cost and power dissipation of analog components often dominate in practical HC systems.Therefore,in this paper,we analyze the baseband HC signal characteristics,including average signal power,power spectral density(PSD),probability density function(PDF),peak-to-average power ratio(PAPR),and complementary cumulative distribution function(CCDF),using a continuous-time HC signal approximation method.Through theoretical analysis and simulation validation,it is proved that the approximation method does not change the average signal power,bandwidth and out-of-band emission(OOBE).The theoretical PDF expression of HC signal with the approximation method is then proposed.Furt her more,the PDF can also explain why the PAPR of baseband continuous-time HC signal is higher than that of discrete-time HC signal.The PAPR performance and the power amplifier(PA)efficiency of HC systems in different conditions are analyzed.Through the PDF analysis of HC signal envelope and the numerical computations of PAPR.it is shown that the approximation method can offer a precise characteristic description for HC signal,which can help to improve the system PAPR performance and the PA efficiency.
文摘加权分数傅里叶变换(Weighted fractional Fourier transform,WFRFT)技术可以极大地改变信号的特性,使信号的统计特性多样化,从而有效地保障通信信息安全。为解决单参数WFRFT通信抗扫描能力不足的问题,以单参数WFRFT为切入点,深入研究单参数分数域的形成机理,分析其潜在的微观特征和暗特征,从而提出了一种基于跳转向量的隐性WFRFT通信方法(Implicit WFRFT communication method of jump vector,IWVJ)。利用调制阶数与星座图的关系,建立了跳变矩阵和跳变向量,并以此制定了控制规则。此外,通过跳变向量控制获得动态调制阶数,从而达到安全通信的目的。仿真结果表明,IWVJ方法对授权接收机具有较高的反变换解调相似度和较低的误码率,相比于具有普适扫描能力的非授权接收机性能更优。同时对解调阶数误差、基础调制阶数和跳转频率等参数的设置给出了适用的建议,使IWVJ方法能够更好地应用于通信系统,为具有抗干扰、抗截获和抗欺骗能力的保密通信提供技术依据。
基金supported by National Natural Science Foundation of China(No.62171445)。
文摘Directional modulation(DM)is one of the most promising secure communication techniques.However,when the eavesdropper is co-located with the legitimate receiver,the conventional DM has the disadvantages of weak anti-scanning capability,anti-deciphering capability,and low secrecy rate.In response to these problems,we propose a twodimensional multi-term weighted fractional Fourier transform aided DM scheme,in which the legitimate receiver and the transmitter use different transform terms and transform orders to encrypt and decrypt the confidential information.In order to further lower the probability of being deciphered by an eavesdropper,we use the subblock partition method to convert the one-dimensional modulated signal vector into a twodimensional signal matrix,increasing the confusion of the useful information.Numerical results demonstrate that the proposed DM scheme not only provides stronger anti-deciphering and anti-scanning capabilities but also improves the secrecy rate performance of the system.
基金the National Natural Science Foundation of China(Grant No.60572094)the Doctorship Foundation of China Educational Depart-ment(Grant No.1010036620602)the National Natural Science Foundation of China for Distinguished Young Scholars(Grant No.60625104)
文摘The fractional Fourier transform （FRFT） has multiplicity, which is intrinsic in fractional operator. A new source for the multiplicity of the weight-type fractional Fourier transform （WFRFT） is proposed, which can generalize the weight coefficients of WFRFT to contain two vector parameters m,n ∈ Z^M . Therefore a generalized fractional Fourier transform can be defined, which is denoted by the multiple-parameter fractional Fourier transform （MPFRFT）. It enlarges the multiplicity of the FRFT, which not only includes the conventional FRFT and general multi-fractional Fourier transform as special cases, but also introduces new fractional Fourier transforms. It provides a unified framework for the FRFT, and the method is also available for fractionalizing other linear operators. In addition, numerical simulations of the MPFRFT on the Hermite-Gaussian and rectangular functions have been performed as a simple application of MPFRFT to signal processing.
