适用于直扩认知通信场合的频谱可控复合序列生成理论与方法

Due to the ability of channel adaptation and low power density communication, Direct-Sequence Spread-Spectrum is most likely to become the supporting technology for the physical layer of cognitive radio. The topic of improving communion communication ability, either between cognitive users or between cognitive user and authorized users, becomes imperative for DSSS cognitive communication system.One possible solution is Spreading sequence generation technology, which provides controllable spectrum characteristics and satisfies the demand of "template concealed".Therefore, theory and method of generating spreading sequence with controllable spectrum structures will be the key technical problem for DS/SS cognitive communication..This project is mainly focused on the conception and solution of generating Spectrum controllable Composite sequences which can be used in DSSS cognitive communication environment. Key research topic: (1) method of generating DSSS cognitive signals based on the co-design of "code type compound" and "waveform shaping"; (2) Mapping theory of binary pseudo stochastic sequence and waveform spectrum characteristics; (3) A general method of generating spectrum characteristics controllable waveform based on the mapping theory of binary pseudo stochastic sequence and waveform spectrum characteristics. .This topic regards theory and method of generating spreading sequence which controls spectrum structures as the research object, which is planned to be mainly studied from theoretical and methodological aspects, and they are as follows: (1) Method of generation of DS/SS cognitive signal based on co-design of code type compound and waveform shaping; (2) binary pseudo stochastic sequence/waveform spectrum characteristic mapping theory; (3) A general method of communication signal waveform whose spectrum characteristic could be controlled, based on binary pseudo stochastic sequence/ waveform spectrum characteristic mapping theory..Through researches mentioned above, we provide theoretical and technical support for implementation of DSSS cognitive communication technology, by exploring theoretical foundations and actual solutions of generating spectrum controllable composite sequences in DSSS cognitive communication environment.

由于具有较强的信道适应能力和低功率密度通信能力，直扩通信方式有望成为认知无线电的物理层支撑技术。如何提高认知用户间和认知用户/授权用户间的共融通信能力，这是直扩认知通信系统急需解决的问题。具有频谱特征可控且满足"掩蔽模板"需求特征的扩频序列生成技术是有望成为解决这一问题的技术途径。因此，频谱可控扩频序列的生成理论与方法成为直扩认知通信的关键性技术问题。.本课题以适用于直扩认知通信场合的频谱可控复合序列生成理论与方法为研究对象，拟从理论和方法两个层面，重点研究（1）基于码型复合和波形成型联合设计的直扩认知信号生成方法、（2）二元伪随机序列/波形频谱特征映射理论、（3）基于二元伪随机序列/波形频谱特征映射理论的频谱特征可控通信波形生成的一般性方法。.通过以上的研究，探索适用于直扩认知通信场合的频谱可控复合序列生成的理论依据和解决方法，为直扩认知通信在认知通信场合的应用提供理论支撑和技术储备。

本课题以适用于直扩认知通信场合的频谱可控复合序列生成理论与方法为研究对象，旨在提高直扩认知用户间和认知用户/授权用户间的共融通信能力。.本课题针对“基于码型复合和波形成型联合设计的直扩认知信号生成方法”的研究，首先从构建具有频谱可控功能的复合序列的单元序列出发，选取几种典型序列，对其代数和相关特性及频谱特征进行研究，获得码元分布的内在规律性和优选方法，扩展了二元伪随机序列选取的种类。其次，通过对不同复合方式的频谱可控复合序列的研究，验证了复合方式的可行性及复合序列功率谱的可控性。最后，在波形成型设计方面，构建基于Walsh函数正交系统的完备正交基，通过加权处理方式，获得满足频谱需求多样化的方法。同时针对基于频谱可控的基带复合序列的直扩认知信号，设计不同的调制函数，改善基带脉冲波形的深陷特征，提高信号频谱可控的灵活性。.本课题针对“二元伪随机序列/波形频谱特征映射理论”的研究，首先利用压缩循环谱理论，获得复合序列中单元序列序号、序列码片速率和信号载频的对应关系；其次从直扩认知系统与窄带授权系统相互影响的角度，利用频谱重叠度概念，为直扩系统提供了一个适用于认知环境下的信号设计准则。并在此基础上，研究使数字扩频系统发射信号具有频谱凹陷功能的方法。.基于以上的研究成果，本课题设计“多址直扩认知通信系统的解决方案”并搭建演示验证平台，主要完成自适应压缩宽带频谱感知、基于复合序列的直扩认知信号的多种捕获方法、设计基于支撑集估计的压缩扩频接收系统和二重扩频通信系统、基于波形集设计的多址直扩认知通信、基于复合序列码位移模型的直扩认知系统等各个关键技术环节的研究。.希望通过以上研究，建立利用特殊伪随机序列的频谱可控特性，实现对授权用户的频带进行规避的认知技术思想，对现有常规认知通信的技术缺陷进行补充，为直扩通信应用于认知通信场合提供理论支撑和技术储备。