| 摘要: |
| 根据上扫频和下扫频线性调频(LFM)信号的特性，针对传统的超宽带无线通信系统中线性调频扩频技术存在的调制效率低、误码率性能低、实现复杂高等问题，结合线性调频（Chirp）扩频以及循环移位编码(CCSK)扩频，提出了一种基于线性调频信号的循环移位线性调频扩频技术(CS-CSS)。首先，将输入数据映射在循环移位因子(CSF)上；然后，根据CSF数值对基带所产生的Chirp信号进行循环移位达到调制的目的；最后，在解调端经过加窗处理、快速傅里叶变换（FFT）得到与发射端对应的CSF，从而得到发送的数据。误符号率的仿真结果与理论推导公式相吻合，从调制效率和误码率性能上讲，该方案相比线性调频二进制正交键控(Chirp BOK)系统具有超过10 dB的误码率性能。因此，该方案具有更好的误码率性能、更高的调制效率及实现更低的复杂度。 |
| 关键词: 超宽带通信 线性调频信号 Chirp扩频调制效率 循环移位编码 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目（61272120）；陕西省科技统筹项目（2016KTZDGY02-04-02） |
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| A new spread spectrum modulation technology based on LFM signal |
| WU Jin,KONG Hui |
| () |
| Abstract: |
| According to the characteristics of the up-chirp and down-chirp linear frequency modulation(LFM) signal,a new spread spectrum technology called Cyclic-Shift Chirp Spread Spectrum(CS-CSS) combing with the Chirp spread spectrum(CSS) and the Cyclic Code-Shift Keying(CCSK) is proposed to solve the problem of low modulation efficiency,low bit error rate(BER) performance and complex implementation in traditional ultra-wide band(UWB) wireless communication systems.Firstly,the input data is mapped on the Cyclic-Shift Factor(CSF). Then,cyclic shift is performed for the Chirp signal collected from baseband and produced by CSF value to realize modulation. Finally,by adding window function processing and fast Fourier transform(FFT) the CSF matching with the transmitter is obtained and the original data is produced. Because the BER-SNR performance between theoretical analysis and simulation is matched,in the perspective of modulation efficiency and BER performance,the proposed scheme has a BER performance over 10 dB compared with Chirp Binary Orthogonal Keying(Chirp BOK) system. In conclusion,it has better BER performance,higher modulation efficiency and easy implementation. |
| Key words: ultra-wide band communication linear frequency modulation signal Chirp spread spectrum modulation efficiency cyclic code shift keying |
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