摘要
针对传统直接序列扩频通信复杂多径环境下性能受限且频谱利用效率低的问题,提出了一种时频混合直接序列扩频接收机结构的循环前缀(CP)块传输结构扩频系统,采用频域最大比合并(MRC)同时实现均衡和解扩过程,在获得最佳接收性能的同时,省略了IFFT过程,显著降低了计算复杂度。在此基础上,提出了利用恒包络零自相关(CAZAC)序列取代m序列作为扩频序列,在不增加计算复杂度的同时显著提升系统的性能。最后,提出了一种基于循环码移位键控(CCSK)的高速扩频通信方法,解决了传统直接序列扩频频谱利用效率低、传输速率受限的问题,并利用傅里叶变换时域循环移位的性质,设计了一种低实现复杂度的CCSK解扩方法,将CCSK解扩所需的乘法次数由O(N^(2))降为O(Nlog N),极大减少了资源消耗。仿真结果表明,相较于已有直接序列扩频方法,所提方法无论是在高斯还是复杂多径信道环境下均获得了3 dB左右的性能增益。
In response to the problem of limited performance and low spectral efficiency in complex multipath environ-ments of traditional direct sequence spread spectrum communication,a cyclic prefix(CP)block transmission structure spread spectrum system with a time-frequency hybrid direct sequence spread spectrum receiver structure was proposed.The system adopted maximum ratio combination(MRC)in the frequency domain to achieve equalization and de-spreading processes simultaneously,while achieving optimal reception performance and omitting the IFFT process to reduce computational complexity significantly.On this basis,it was proposed to replace the m-sequence with the constant amplitude zero auto correlation(CAZAC)sequence as the spread spectrum sequence,which significantly improved the system performance without increasing computational complexity.Finally,a high-speed spread spectrum communication method based on cyclic code shift keying(CCSK)was proposed to solve the problems of low spectrum utilization effi-ciency and limited transmission rate in traditional direct sequence spread spectrum.By utilizing the property of Fourier transform time-domain cyclic shift,a low implementation complexity CCSK decoding method was designed,which re-duced the multiplication number required for CCSK de-spreading by O(N^(2))reduced to O(Nlog N),greatly reducing resource consume.The simulation results show that compared to existing direct sequence spread spectrum methods,the proposed method achieves approximately 3 dB gain in both Gaussian and complex multipath channel environments.
作者
辜方林
彭进霖
黄育侦
曹圣群
赵海涛
魏急波
GU Fanglin;PENG Jinlin;HUANG Yuzhen;CAO Shengqun;ZHAO Haitao;WEI Jibo(School of Electronic Science,National University of Defense Technology,Changsha 410073,China;Chinese Academy of Military Science,Beijing 100097,China;Intelligent Perception and Processing Laboratory,Beijing 100094,China)
出处
《通信学报》
EI
CSCD
北大核心
2023年第12期78-85,共8页
Journal on Communications
基金
国家自然科学基金资助项目(No.61931020)。
关键词
直接序列扩频
最大比合并
循环码移位键控
实现复杂度
direct sequence spread spectrum
maximum ratio combination
cyclic code shift keying
implementation complexity
