Journal of South China University of Technology (Natural Science Edition) ›› 2010, Vol. 38 ›› Issue (2): 116-120.doi: 10.3969/j.issn.1000-565X.2010.02.022

• Electronics, Communication & Automation Technology • Previous Articles     Next Articles

Fast Synchronization for M-Ary Orthogonal Spread Spectrum

Xiong Hai-liang1 Li Wen-gang1  Sun De-chun1 Yang Hong1.2  Yi Ke-chu 1   

  1. 1. State Key Laboratory of Integrated Service Networks, Xidian University, Xi＇an 710071, Shaanxi, China; 2. Institute of Spacecraft System Engineering, China Academy of Space Technology, Beijing 100094, China
  • Received:2009-02-19 Revised:2009-06-28 Online:2010-02-25 Published:2010-02-25
  • Contact: 熊海良（1981-），男，博士生，主要从事数字通信、导航与定位研究． E-mail:hlxiong@mail．xidian．edu．cn
  • About author:熊海良（1981-），男，博士生，主要从事数字通信、导航与定位研究．
  • Supported by:

    国家自然科学基金资助项目（60572148,60702060）;高等学校学科创新引智计划项目（B08038）

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Abstract:

Proposed in this paper is a novel method of M-ary orthogonal spread spectrum, with which the potential periodicity of transmitted signals is eliminated and the data are hard to detect or intercept. Thus, both the anti-jamming and the anti-intercept capabilities of the system are well guaranteed. In the condition of long pseudo code and large carrier Doppler frequency shift, the number of FFT points in the conventional synchronous acquisition algorithm is too large, the complex multiplication is of high computational complexity and large time cost, and the parameter evaluation acquired in a long duration is not applicable for carrier tracking because it is too old. In order to solve these problems, an improved fast synchronous acquisition algorithm is proposed, which helps to search for the code synchronization point and estimate the cartier frequency offset for correction, with the computational complexity obviously reduced.

Key words: M-ary orthogonal spread spectrum, Doppler frequency shift, synchronous acquisition, carrier frequency offset