实用性非相关混沌数字调制技术关键问题研究

Compared with traditional direct sequence spread spectrum communications, non-coherent chaotic digital modulation technology will have broad application prospects due to some advantages, including good privacy, simple circuits, free of channel estimation, no need for spread spectrum code synchronization and so on. At present, two critical problems need to be solved when non-coherent chaotic digital modulation technology is used: on one hand, restricted by current integrated electronic technology, the required delay lines are difficult to implement and hard to integrate in high speed communications; on the other hand, all proposed multi-access schemes are affected by the transmitted reference, which degrades the system performance and makes performance enhancement inevitable. As a result, from the view point of practicability, this project intends to study aforementioned key issues deeply, and our research mainly includes: (1) Utilize new orthogonal separation mechanism for signal concurrent transmission to construct simple, applicable and delay-line-free communication systems based on non-coherent chaotic digital modulation and find practical solutions to improving their performance under different transmission conditions. (2) Design novel multi-access communication schemes in which the negative effects from transmitted reference are weakened or eliminated so as to achieve better performance (such as enhanced data security, reduced multi-user interferences and decreased bit error rate et al) and to improve the system practicality. Studies on our project will help to open the way for non-coherent chaotic digital modulation to step into the practical application stage in multi-user and high speed communications.

与传统直接序列扩频通信相比，非相关混沌数字调制技术具有保密性好、电路简单、无需信道估计和扩频码同步等优势，因此展现出了广阔的应用前景。现阶段，非相关混沌数字调制技术在实际应用中有两个关键问题亟待解决：一方面，受到当前集成电子工艺的限制，系统必需的延时线在高速通信中难以实现、不易集成；另一方面，已有的多址方案都受到传输参考的不利影响，系统性能有待改善。因此，本课题从实用性的角度出发，拟对上述关键问题展开深入研究，主要研究内容包括：(1)利用新的信号正交分隔传输机制，构造简单实用的无延时线非相关混沌数字调制通信系统，针对不同的传输条件探索相应的性能提升方法；(2)在设计多址通信方案时考虑减小或消除传输参考的负面影响，改善系统性能（如：数据安全性、用户间干扰、比特误码率等），增强系统的实用性。本课题的研究可以为非相关混沌数字调制技术在多用户高速通信中的应用迈入实用阶段扫清障碍。

本项目从实用性角度出发，主要围绕无延时线非相关混沌数字调制技术以及减弱传输参考对多址系统性能不利影响的相关策略这两个方面展开了深入研究。本项目严格按照研究计划进行，实现了预期目标，取得了一系列创新成果：1）基于QPSK中的同相信道和正交信道，提出了一种全新的无延时传输参考信号分隔机制；2）分别针对FM-DCSK和DCSK系统，构造了基于QPSK的简单无延时线数字调制解调系统；3）在新构建的基于QPSK的无延时线数字调制解调系统中引入多级正交DCSK调制，大幅提升系统比特传输速率；4）将多载波技术和多级CSK调制相结合，设计了适合现代无线移动通信的多载波混沌移位键控调制通信系统；5）基于频率分集技术，探索了多载波DCSK系统中的减噪方法，减小参考信号和信息信号中的噪声；6）研究了减弱传输参考对多址系统性能不利影响的相关策略；7）设计了基于Walsh码的CDSK多用户混沌数字通信方案。上述创新成果，为非相关混沌数字调制技术在多用户高速通信中的应用迈入实用阶段奠定了理论基础。.在本项目的支持下，项目组成员已经在IEEE Transactions on Circuits and Systems I: Regular Papers、IEEE Transactions on Circuits and Systems II: Express Briefs、International Journal of Bifurcation and Chaos等权威期刊以及NOLTA、IWCFTA等知名国际会议上发表或录用高水平论文20篇（其中SCI收录10篇），申请国家发明专利2项，出版中文学术专著1本。