具有两级互碰撞特性的新型跳频序列集构造

为实现无线通信网灵活的多级误码率传输保证,从跳频通信的物理层技术出发,提出了一类随机性较好且具有两级互碰撞特性的新型跳频序列集。基于传统汉明最优跳频序列和代数变换,给出了一类满足两级互碰撞特性的跳频序列集的构造算法,通过实例和仿真分析了该跳频序列集的频点碰撞特性。与传统跳频序列集相比,该类跳频序列可提供两级灵活的互碰撞值,为实现跳频多址接入系统两级误码率传输保证提供了基础。该序列具有明显的性能优势,在未来民用和战术跳频通信中具有广阔的应用前景。     

一种新的低/零碰撞区跳频序列集构造方法

低/零碰撞区跳频序列能够应用于准同步跳频通信系统中以缓解多址干扰的影响。提出了一种新的基于交织方法的低/零碰撞区跳频序列集构造方法。针对序列集的不同参数设计合理的移位序列,通过交织变换构造具有最优或次优性的低/零碰撞区跳频序列集。对不同参数进行了数值仿真,得到和所提方法一致的结论,且该方法构造的序列集具有更低的周期碰撞次数,实用性更强。新的低/零碰撞区跳频序列集可以应用于准同步跳频通信系统中,从而获得更优的性能。     

Z4上两类具有最优自相关四元序列的线性复杂度研究

线性复杂度是序列密码中重要的安全性指标.针对Z4上两类具有最优自相关的四元序列,对其线性复杂度进行研究.利用Galois理论,分别得到了由Legendre序列、双素数序列及广义GMW序列构造的四元序列线性复杂度的精确值.     

一类混沌跳频序列的性能分析

对一类基于混沌映射,由混沌轨道多值量化和比特抽取相结合产生的跳频序列进行了性能分析。理论分析和统计性能实验表明,该方法构造的跳频序列是贝努利随机序列,其汉明相关函数服从泊松分布。在相同的条件下(频率数目和序列长度相同),其均匀分布性、汉明相关值和线性复杂度与其它方法产生的混沌跳频序列相当,然而其所需的迭代次数却大大减少,从而能够产生更多的跳频序列,非常适合在跳频多址通信中应用。     

跳码直扩系统的伪随机序列应用

跳码直扩及扩展的跳码／跳频通信系统中,扩频序列随时间跳变,系统抗干扰和反侦察性能有一定程度的增强。通过Berlekamp-Massey迭代算法对GOLD序列与DFS结构的混沌序列进行线性复杂度分析,结果表明低线性复杂度的码字反侦察性能差,进而将影响跳码直扩系统抗相关干扰的性能,而混沌序列在随机特性尤其是线性复杂度方面的性能良好,因而在跳码直扩系统中具有重要的应用价值。     

跳码直扩系统的伪随机序列应用

跳码直扩及扩展的跳码/跳频通信系统中,扩频序列随时间跳变,系统抗干扰和反侦察性能有一定程度的增强.通过Berlekamp-Massey迭代算法对GOLD序列与DFS结构的混沌序列进行线性复杂度分析,结果表明低线性复杂度的码字反侦察性能差,进而将影响跳码直扩系统抗相关干扰的性能,而混沌序列在随机特性尤其是线性复杂度方面的性能良好,因而在跳码直扩系统中具有重要的应用价值.     

有大线性复杂度的FH码序列

本文进一步研究了P.V.Kumar提出的跳频码序列的构造方法,分析了两种码序列的线性复杂度,并就第二种码序列给出了一种保证有大线性复杂度的构造方法。     

基于混沌序列的无碰撞区跳频序列构造方法

为了提升多用户跳频系统在复杂场景下的顽存能力，提出了一种基于成熟的混沌序列构造性能优良的无碰撞区跳频序列集的方法。与已有的无碰撞区跳频序列构造方法相比，该方法能够利用已有混沌序列在高复杂度和长周期性能方面的良好性质，构造的序列集能够达到非汉明相关的理论界。理论分析和仿真结果表明，该方法构造的序列具有更好的均匀性、随机性、复杂度等统计特性，为跳频通信系统在多用户组网通信应用时提供更强的安全可靠性。     

基于混沌的宽间隔跳频序列

提出了一种用混沌映射方法产生党间隔跳频序列的方法,分析了混沌宽间隔跳频序列的平衡特性及汉明相关特性,并讨论了序列的线性复杂度和抗破译能力。实验表明,该跳频序列性能良好,适用于短波跳频系统。     

交织法构造无碰撞区跳频序列集

为构造一类适用于跳频通信系统的跳频序列集,基于移位序列和交织法,提出了一种新的构造NHZ(无碰撞区)跳频序列集的方法。该方法得到的NHZ跳频序列集的参数可以达到理论界限,是一类最优NHZ跳频序列集,并且参数可以灵活设定。与已有的方法相比,得到的NHZ序列集中序列长度大于频点个数,该类NHZ序列集可以适用于更多的场合。     

新的具有最优平均汉明相关性的跳频序列族

平均汉明相关值是评价跳频序列族性能的一个重要参数。首先给出了Whiteman广义分圆类的一个推广,并且给出该推广的分圆类的一些性质。其次,基于推广的Whiteman广义分圆类构造了新的跳频序列族,并证明了新构造的跳频序列族关于平均汉明相关界是最优的。     

Algebraic Constructions of Optimal Frequency-Hopping Sequences

Frequency-hopping (FH) spread spectrum and direct-sequence spread spectrum are two main spread-coding technologies. Frequency-hopping sequences are needed in FH code-division multiple-access (CDMA) systems. In this correspondence, three classes of optimal frequency-hopping sequences are constructed with algebraic methods. The three classes are based on perfect nonlinear functions, power functions, and norm functions, respectively. Both individual optimal frequency-hopping sequences and optimal families of frequency-hopping sequences are presented.     

d-元广义分圆序列的线性复杂度及自相关函数性质分析

该文推广了Liu Fang等人(2010)给出的周期为pn, p为奇素数,n为正整数的广义分圆序列的构造,并确定了新构造序列的线性复杂度和自相关函数值的分布。结果表明,推广的构造保持了原构造的高线性复杂度等伪随机特性。由于取值更灵活,较之原构造新构造序列的数量要大得多。     

Frequency-hopping code sequence designs having large linear span

In frequency-hopping spread-spectrum multiple-access communication systems, it is desirable to use sets of hopping patterns that, in addition to having good Hamming correlation properties and large period, are also derived from sequences having large linear span. Here, two such frequency hopping code sequence designs that are based on generalized bent functions and generalized bent sequences are presented. The Hamming correlation properties of the designs are optimal in the first case and close to optimal in the second. In terms of the alphabet size p (required to be prime in both cases), the period and family size of the two designs are given by (p², p) and (p ⁿ, p^n/2+1) (n an even integer), respectively. The finite field sequences underlying the patterns in the first design have linear span exceeding p, whereas still larger linear spans (when compared to the sequence period) can be obtained using the second design method     

一种混沌序列密码的产生

受到时延混沌系统对时延时间段初值函数极端敏感特点的启发,利用一一映射与混沌映射相组合在数字滤波器的结构上产生混沌密码序列,使序列同样受到时延时间段初值的影响,增加序列的复杂度,提高保密通信的安全性,并给出了理论分析。同时对该序列的相关性等特性进行了模拟,将其与混沌跳频、非一一映射所产生的混沌序列进行比较,证明了该方法是可行性。     

Linear complexity of quaternary sequences with odd period and low autocorrelation

Equivalence between two classes of quaternary sequences with odd period and best known autocorrelation are proved. A lower bound on the linear complexity of these sequences is presented. It is shown that the quaternary sequences have large linear complexity to resist Reeds and Sloane algorithm attack effectively.     

One-coincidence sequences with specified distance between adjacentsymbols for frequency-hopping multiple access

Frequency hopping spread-spectrum systems have been popular in multiple-access communication systems. In such frequency-hopping multiple-access systems, multilevel sequences are used to specify which frequency will be used for transmission at any given time. One-coincidence sequences with specified distance between adjacent symbols for frequency-hopping multiple access are described. In such sequences, the distances between any adjacent symbols in any sequence are more than some specified amount. A theoretical bound is derived for the sequences, and two theorems on the construction of the sequences are given     

Comments on `Code acquisition for a frequency-hopping system'

For the original article see ibid., vol.COM-35, no.5, p.566-8 (1987). It is pointed out that in the paper by I. Vajda and G. Einarsson the proposed sets of frequency-hopping sequences, that permit the correct resynchronization in FH-MFSK (frequency-hopping multiple-frequency-shift-keyed) multiple-access systems, are only the special case of the Reed-Solomon sets of asynchronous frequency-hopping sequences previously derived. For the case when the number of available frequencies is prime, another class of FH-MFSK sequences with good resynchronization and interference properties is presented     

Fp上pn-周期序列的1-错线性复杂度

周期序列的线性复杂度和k-错线性复杂度是衡量密钥流序列随机性的两个重要指标.该文给出了Fp上pn-周期的序列所有可能的1-错线件复杂度的值以及具有给定1-错线性复杂度的序列个数.更进一步,该文给出了Fp上pn-周期的序列1-错线性复杂度的期望.     

GF(3)上新型自缩控序列的周期与线性复杂度

Self-Shrinking Control (SSC) sequences are a class of important pseudo-random sequences, and pseudo-random sequences are widely used in many fields, such as communication encryption, recoding technology. In these applications, sequences are usually required to have large periods and high linear complexity. In order to construct pseudo-random sequences with higher period and higher linear complexity, a new SSC sequence model based on the m-sequence in GF (3) is constructed, the period and the linear complexity of the generated sequence are studied by using finite domain theory, this model greatly improves the period and the linear complexity of the generated sequence, and obtains a more accurate upper bound value of the linear complexity of the generated sequence. Thus, the anti-attack ability and security performance of the generated sequence in communication encryption are improved.