The search functionality is under construction.
The search functionality is under construction.

Keyword Search Result

[Keyword] periodic autocorrelation(8hit)

1-8hit
  • New Almost Periodic Complementary Pairs

    Jiali WU  Rong LUO  Honglei WEI  Yanfeng QI  

     
    LETTER-Communication Theory and Signals

      Pubricized:
    2021/03/05
      Vol:
    E104-A No:9
      Page(s):
    1361-1364

    In this letter, we give a recursive construction of q-ary almost periodic complementary pairs (APCPs) based on an interleaving technique of sequences and Kronercker product. Based on this construction, we obtain new quaternary APCPs with new lengths.

  • 16-QAM Sequences with Good Periodic Autocorrelation Function

    Fanxin ZENG  Yue ZENG  Lisheng ZHANG  Xiping HE  Guixin XUAN  Zhenyu ZHANG  Yanni PENG  Linjie QIAN  Li YAN  

     
    LETTER-Sequences

      Vol:
    E102-A No:12
      Page(s):
    1697-1700

    Sequences that attain the smallest possible absolute sidelobes (SPASs) of periodic autocorrelation function (PACF) play fairly important roles in synchronization of communication systems, Large scale integrated circuit testing, and so on. This letter presents an approach to construct 16-QAM sequences of even periods, based on the known quaternary sequences. A relationship between the PACFs of 16-QAM and quaternary sequences is established, by which when quaternary sequences that attain the SPASs of PACF are employed, the proposed 16-QAM sequences have good PACF.

  • Aperiodic Complementary Sequences

    Zhimin SUN  Xiangyong ZENG  Yang YANG  

     
    LETTER-Communication Theory and Signals

      Vol:
    E97-A No:9
      Page(s):
    1998-2004

    For an integer q≥2, new sets of q-phase aperiodic complementary sequences (ACSs) are constructed by using known sets of q-phase ACSs and certain matrices. Employing the Kronecker product to two known sets of q-phase ACSs, some sets of q-phase aperiodic complementary sequences with a new length are obtained. For an even integer q, some sets of q-phase ACSs with new parameters are generated, and their equivalent matrix representations are also presented.

  • On Binary Sequence Pairs with Two-Level Periodic Autocorrelation Function

    Kai LIU  Chengqian XU  

     
    PAPER-Sequences

      Vol:
    E93-A No:11
      Page(s):
    2278-2285

    Binary sequence pairs as a class of mismatched filtering of binary sequences can be applied in radar, sonar, and spread spectrum communication system. Binary sequence pairs with two-level periodic autocorrelation function (BSPT) are considered as the extension of usual binary sequences with two-level periodic autocorrelation function. Each of BSPT consists of two binary sequences of which all out-phase periodic crosscorrelation functions, also called periodic autocorrelation functions of sequence pairs, are the same constant. BSPT have an equivalent relationship with difference set pairs (DSP), a new concept of combinatorial mathematics, which means that difference set pairs can be used to research BSPT as a kind of important tool. Based on the equivalent relationship between BSPT and DSP, several families of BSPT including perfect binary sequence pairs are constructed by recursively constructing DSP on the integer ring. The discrete Fourier transform spectrum property of BSPT reveals a necessary condition of BSPT. By interleaving perfect binary sequence pairs and Hadamard matrix, a new family of binary sequence pairs with zero correlation zone used in quasi-synchronous code multiple division address is constructed, which is close to the upper theoretical bound with sequence length increasing.

  • Construction of Multi-Dimensional Periodic Complementary Array Sets

    Fanxin ZENG  Zhenyu ZHANG  

     
    LETTER-Information Theory

      Vol:
    E93-A No:7
      Page(s):
    1392-1395

    Multi-dimensional (MD) periodic complementary array sets (CASs) with impulse-like MD periodic autocorrelation function are naturally generalized to (one dimensional) periodic complementary sequence sets, and such array sets are widely applied to communication, radar, sonar, coded aperture imaging, and so forth. In this letter, based on multi-dimensional perfect arrays (MD PAs), a method for constructing MD periodic CASs is presented, which is carried out by sampling MD PAs. It is particularly worth mentioning that the numbers and sizes of sub-arrays in the proposed MD periodic CASs can be freely changed within the range of possibilities. In particular, for arbitrarily given positive integers M and L, two-dimensional periodic polyphase CASs with the number M2 and size L L of sub-arrays can be produced by the proposed method. And analogously, pseudo-random MD periodic CASs can be given when pseudo-random MD arrays are sampled. Finally, the proposed method's validity is made sure by a given example.

  • Multiple L-Shift Complementary Sequences

    Yan XIN  Ivan J. FAIR  

     
    PAPER-Sequences

      Vol:
    E89-A No:10
      Page(s):
    2640-2648

    We introduce an extension of Golay complementary sequences in which, for each sequence, there exists another sequence such that the sum of aperiodic autocorrelation functions of these two sequences for a given multiple L-shift (L≥1) is zero except for the zero shift. We call these sequences multiple L-shift complementary sequences. It is well-known that the peak-to-average power ratio (PAPR) value of any Golay complementary sequence is less than or equal to 2. In this paper, we show that the PAPR of each multiple L-shift complementary sequence is less than or equal to 2L. We also discuss other properties of the sequences and consider their construction.

  • Searching for the Best Biphase and Quadriphase Quasi-Barker Sequences

    Ka Ming HO  Wai Ho MOW  

     
    LETTER

      Vol:
    E89-A No:9
      Page(s):
    2341-2344

    Barker sequences have been used in many existing communications and ranging systems. Unfortunately, the longest known biphase and quadriphase Barker sequences are of lengths 13 and 15, respectively. In this paper, we introduce the so-called quasi-Barker sequences which achieve the minimum peak sidelobe level one within a certain window centered at the mainlobe. As our key results, all the best biphase and quadriphase quasi-Barker sequences of lengths up to 36 and 21, respectively, were obtained by an efficient computer search. These sequences may provide better multipath resistance and tracking accuracy in ranging applications.

  • Autocorrelation Properties of Unified Complex Hadamard Transform Sequences

    Wee SER  Susanto RAHARDJA  Zinan LIN  

     
    LETTER-Spread Spectrum Technologies and Applications

      Vol:
    E85-A No:10
      Page(s):
    2280-2282

    The UCHT (Unified Complex Hadamard Transform) has been proposed as a new family of spreading sequences for DS-SSMA systems recently. In this Letter, the periodic autocorrelation (PAC) properties of the Unified Complex Hadamard Transform (UCHT) sequences are analyzed. Upper bounds for the out-of-phase PAC are derived for two groups of the UCHT sequences, namely the HSP-UCHT and the NHSP-UCHT sequences (the later is a more general representation of the well-known Walsh-Hadamard (WH) sequences). A comparison of the two bounds is performed. It turns out that the HSP-UCHT sequences have a lower upper bound for the out-of-phase PAC. This makes the HSP-UCHT sequences more effective than the WH sequences in combating multipath effect for DS-SSMA systems.