基于分块FFT的CSK调制信号高效解调算法  

An Efficient Demodulation Algorithm for CSK Modulated Signals Based on Block FFT

作　　者：李晔 张墩利 肖园园 陈华明[2] LI Ye;ZHANG Dunli;XIAO Yuanyuan;CHEN Huaming(College of Intelligent Manufacturing,Hunan Open University,Changsha 410004,China;College of Electronic Science and Technology,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]湖南开放大学智能制造学院,湖南长沙410004 [2]国防科技大学电子科学学院,湖南长沙410073

出　　处：《无线电工程》2023年第6期1321-1327,共7页Radio Engineering

基　　金：国家自然科学基金(61801522)。

摘　　要：码移键控(Code Shift Keying,CSK)调制通过增加码相位偏移维度,能够在不改变信号频谱的基础上提高电文速率。由于CSK调制信号在解调时需要计算各种码相位偏移的相关值,因此会显著增加接收端电文解调的复杂度。为了降低CSK信号解调的复杂度,提出了基于分块快速傅里叶变换(Fast Fourier Transform,FFT)的高效解调算法。该算法对重采样后的基带数据进行奇偶分块,将传统时域循环相关转换为频域乘积运算,并基于高效的FFT算法达到降低相关值计算复杂度的目的。对于CSK(6,1023)调制,所提算法需要的复乘法和复加法仅约为传统时域相关算法的17.2%和31.2%,大幅降低了CSK信号解调的计算复杂度。Code Shift Keying(CSK)modulation could improve the message rate without changing the spectrum by adding the dimension of code phase offset.However,the correlation values of various code phase offsets are needed and the computational complexity of the message demodulation at the receiving end will be significantly increased.In order to reduce the complexity of CSK signal demodulation,an efficient demodulation algorithm based on block Fast Fourier Transform(FFT)is proposed.The algorithm firstly divides the resampled baseband signal into odd and even blocks,and then converts the traditional time domain cyclic correlation into frequency domain product.For CSK(6,1023)modulation,the complex multiplication and complex addition required by the proposed algorithm are only about 17.2%and 31.2%of the traditional algorithm,which greatly reduce the computational complexity of signal demodulation.

关 键 词：卫星导航 低轨导航增强系统 CSK调制 信号解调 计算复杂度 

分 类 号：TN96[电子电信—信号与信息处理]