On the other hand , the present research results were mainly about the narrowband interference mitigation , and the influence of wideband nonstationary interference for dsss is more important , so we should research more noval anti - jam technology and systems in the military environment 此外,大多数抗干扰研究成果集中在窄带干扰抑制上,宽带非平稳干扰对扩频系统的影响逐渐引起人们重视。因此,需要研究新型的抗干扰技术与体系。
Thirdly , the dissertation presents an anti - interference technology of adaptive array for non - spread spectrum signal using a pilot signal , by which a non - spread spectrum system can use the decoupled 2 - d rake receiver and the original non - spread spectrum system need not be modified 第三，提出了采用扩频信号作为导引信号的非扩频信号自适应阵列天线抗干扰方法。该方法使得非扩频系统可以采用解耦合空时2 - drake接收机，而且不改变原非扩频系统。
This thesis investigates the application and implementation of adaptive array based on mmse criteria in the presence of strong man - made interferences and aperiodic spread spectrum codes , including reference signal generating , afc in adaptive antennas array , and an application of adaptive antennas for a general non - spread spectrum signal , ssb ( single sideband ) communication system is presented . the thesis is outlined as follows 论文研究了在强人为干扰和非周期扩频码情况下，基于mmse准则的扩频系统自适应天线阵的实现和应用问题，包括参考信号提取、自适应天线阵中的afc ，并给出了在非扩频信号单边带ssb ( singlesideband )信号通信系统中的自适应天线的应用。
Multicarrier wireless communications have been widely investigated in the past decades . recently , two - dimensional spread spectrum ( 2d - ss ) system has drawn a lot of attention because of its full utilization of spreading characteristics in the frequency domain and time domain . compared with multicarrier code division multiplex access ( mc - cdma ) , 2d - ss system can effectively mitigate multiple access interference ( mai ) due to spreading in the time domain 当前多载波无线通信技术得到了广泛的研究,二维扩频通信系统是近年来提出的新的扩频通信方式,由于二维扩频系统从时域和频域上分别对数据信号进行频谱扩展,因此它同时具有时域扩频和频率扩频通信系统的特点,是对传统的一维时域直接序列扩频和多载波扩频的推广。
To assure that the hybrid ds - fh spread - spectrum communication mode has better capability of information safety and inference suppression , i bring forward a design scheme of ds - fh spread - spectrum communication system and solving effectively the crucial problem such as how to choose the user address , how to choose the hopping frequency and how to avoid the collision of the frequency which is used by different users at the same time 为保证系统可靠、有效地工作，本文提出了一种ds - fh混合扩频系统的设计方案，并且有效地解决了系统的用户选址、频率选择和频率碰撞等关键问题。通过系统设计仿真证实了ds - fh混合扩频系统具有优于ds系统的抗干扰性能，并在一定程度上提高了系统的抗远近效应能力。
Secondly , we apply tk operator to the cross - correlation of received signal code and pn code to separate the multi - paths . it comes to a conclusion that tk operator can separate the multi - paths within less than the chip period accurately of spread - spectrum system with space - modulation by simulation . at last , we apply this algorithm to the practical signal collected by gps tap , and from the result we can drop a conclusion the tk algorithm is practical 本文首先阐述了时空调制扩频信号原理以及在多径干扰下时空调制接收机的性能和teager - kaiser接收机的原理;接着对时空调制扩频系统的解调信号与伪码的互相关函数采用tk接收机进行多径分离,仿真结果表明, tk接收机对时延在一个码片内的时空调制扩频通信多径信号有很好的分离效果;最后用数据采集器对一个gps信号进行接收和多径的估计,验证了该算法在实际的运用中对多径的扩频信号有很好的分离效果。
