跳频抗干扰系统的空时编码技术研究

【作者】 杨坤；

【导师】 武刚；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2009， 硕士

【摘要】 在无线通信环境中,多径衰落信道导致的字符间干扰,及其他信号发射源产生的有意或无意的干扰,如部分频带干扰、多音干扰、转发式干扰,都会造成接收端接收到的信号失真,系统误码率增加,通讯质量降低。跳频技术以其优良的抗干扰性能和多址组网性能,已成为军用抗干扰通信的主流技术。与快跳频技术相比,慢跳频技术并不能获得频率分集增益,迫切需要引入新的分集技术,以提高其链路传输性能。近十几年中,较多的研究关注于结合多天线接收分集的慢跳频系统的设计与性能分析。而随着多天线发射分集技术的发展,结合空时码的慢跳频系统则成为了基于多天线信号处理及编码对跳频系统的一个重要研究方向。其中,空时分组码,以及由空时分组码衍生的空频分组码、空时频分组码由于具有较低的解码复杂度,且可提供多天线分集增益,而得到广泛的研究。因此,本论文主要研究了基于空时分组码的慢跳频技术的设计方法与系统性能。并且,在多种衰落和干扰信道下,对慢跳频-空时分组码系统与慢跳频-空时频分组码系统进行了性能仿真研究。重点分析和讨论了不同系统设计方案性能增益的差别。论文第一部分概述了跳频与空时编码技术,以及跳频抗干扰系统与多天线技术结合的研究现状,并指出了本文的主要贡献。论文第二部分首先综述了跳频抗干扰技术的系统模型与信号模型,并分别研究了信道中的衰落因素对慢跳频系统抗干扰性能的影响,以及空时分组码对信道中的衰落因素的抑制效果。在上述研究基础上,本论文给出了跳频抗干扰系统与多天线发射技术结合的一般系统模型与信号模型,并提出了一种基于空时分组码的慢跳频技术的两种系统设计方案:慢跳频-空时分组码系统和慢跳频-空时频分组码系统。最后给出了空时码与慢跳频系统结合——即广义多天线慢跳频系统的空时编码技术的设计准则。论文第三部分首先在准静态衰落、瑞利衰落和多径衰落三种衰落信道条件下进行了大量的计算机仿真,研究比较了所提方案在部分频带干扰、多音干扰、转发式干扰环境下的抗干扰性能增益,并进一步提出了基于空时分组码的慢跳频技术在多径衰落信道下的性能提升方案。最后,论文的第四部分对全文进行了总结,并指出了未来的研究方向。更多还原

【Abstract】 In wireless communication environments, the reliability of received signals degrade seriously at the receiver, because of the inter symbol interference (ISI) caused by multipath fading channels and intentional or accidental jamming from other signals, such as partial-band noise jamming (PBNJ), multi-tone noise jamming (MTNJ) and follower jamming. Frequency-hopping (FH) technology for its excellent performance of anti-jamming and multiple access networks has become the mainstream of military anti-jamming communications technology. Compared with the fast frequency-hopping (FFH) technology, the slow frequency-hopping (SFH) technology can not get the frequency diversity gain. Therefore, in order to improve the performance of SFH transmission link, there is an urgent need to introduce diversity technology.The last ten years, more research attention to the design and performance analysis about a combination of multi-antenna receive diversity and SFH system. With the progress of multi-antenna transmit diversity technology, the combination of space-time coding (STC) and SFH system has become based on the multi-antenna signal processing and coding of the FH system as an important research direction. Among them, the space-time block coding (STBC), as well as space-frequency block coding (SFBC) and space-time-frequency block coding (STFBC) derived from STBC, because of their lower decoding complexity and providing multi-antenna diversity gain, have been extensive research.Therefore, the design methods and system performance of the SFH technology based on STBC are investigated in this thesis, as well as the corresponding performance simulation is investigated in a variety of fading and jamming channels. Analysis and discussion focus on the difference between the performance gain of the two system design.The first part, we give an overview of the status and progress of the FH and STBC, as well as the combination of multi-antenna technology and FH system, and indicate the main contribution of this thesis.The second part, the system model and signal model of FH system are detailedly summarized. According to the anti-fading performance study of SFH system and STBC system, the general system model and signal model about the combination of multi-antenna transmit technology and FH system are given, and we propose two system design of a SFH technology based on STBC: slow frequency-hopping - space-time block coding (SFH-STBC) system and slow frequency-hopping - space-time-frequency block coding (SFH-STFBC) system, as well as the design criteria for the combination of STC and SFH is given.The third part, the performance gain simulation are investigated and compared over jamming environments (PBNJ, MTNJ and follower jamming) and three types of fading channels, quasi-static fading, Rayleigh fading and multipath fading channels, and the schemes to increase the performance of the SFH technology based on STBC over multipath fading channels are proposed.Finally, some conclusion of the whole dissertation is drawn, and the further research issues and possible direction are pointed out.更多还原