差分跳频软正交多址及其增强技术

【作者】 邢卫民；

【导师】 李少谦；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2010， 硕士

【摘要】 作为短波跳频通信的一个重要方向,差分跳频(DFH)受到了很多研究人员的关注,这种相关跳频方式可以提供比以往跳频系统更快的数据传输速率和更好的抗干扰抗截获性能。另外,差分跳频系统平台全面基于DSP数字系统,是短波跳频数字化的一个重要突破。许多学者对DFH体制的基本性能做了大量研究,目前有关频率转移函数G函数和频率序列译码的论著已有很多,但是,有关DFH多址技术和组网技术的研究却是基本空白,这也是DFH至今没有真正大规模应用的一个重要原因。本文就是从DFH多址这一必须要认真研究的方面出发,提出自己的一套多址方案。本文在介绍了差分跳频技术的基本特点之后,首先将常用的多址技术应用于DFH进行了研究探讨,在公平比较原则下,得出了DFH的频分多址方式的AWGN信道下性能要优于时分多址方式,但是其扩频抗干扰能力相对要弱于时分多址方式这一结论。同时也研究了针对G函数族设计的码分多址方式。由于这种方式还处于可能性讨论阶段,所以本文只提出了一种针对双用户的分散频率碰撞点的G函数设计,虽然本文没能将这种方式扩展至多用户情况,但是仍然可以考虑将它作为一种可行的双工技术。本文的重点是提出了一种差分跳频软正交多址方式,它结合了差分跳频频分多址和传统跳频码分多址的优势,该方式的地址码由类似传统跳频的跳块序列码来实现,纠错性能由差分编码实现,根据地址码的设计分为正交和准正交两种情况,该方式在不降低用户跳扩频增益的前提下,在同步正交编码时,系统的AWGN误码性能与差分跳频频分多址性能相同。在准正交编码多址的情况下,系统为干扰受限系统,针对这一情况,本文采用了一种并行多址干扰消除接收技术来提高系统性能,并验证了这种技术的有效性。论文最后,对研究工作进行了归纳,并提出了进一步研究的研究内容和方向。更多还原

【Abstract】 As an important direction for short wave frequency hopping technology, differential frequency hopping has been the concern of many researchers. This kind of correlated frequency hopping system can provide a data transfer speed faster than ever before, and better resistance to jamming and interception capabilities. The DFH radio basically based on the DSP platform, so it is an important breakthrough in frequency hopping system digitalization. Due to the efforts of many scholars, the papers of the G function and frequency sequence decoding of DFH is vary more, but the research of DFH multi-access and networking technology is basically a blank, This is one important reason why DFH is not in equipment. This paper is from the point of DFH multi-access and proposed my own solutions.After describes the basic characteristics of differential frequency hopping technology, this paper at first studied the performance of DFH system when using traditional multi-access method. Under conditions of fair, find out that DFH frequency division multiple access method is superior to time-division multiple access method in AWGN performance, but its spread-spectrum anti-jamming capability is weaker than TDMA method. This paper also studied the design of G function family for multi-access approach. Because of this approach is still at the discussion stage of possibility, here just designed one approach for two users’condition, which is to decentralize frequency collision to design the G function. Although this approach can not be extended up to the case of multi-user, it is also can be a solution of duplex technology.The focus of this paper is to present a soft-orthogonal multiple access method of differential frequency hopping, and this method is a combination of DFH frequency division multiple access method and traditional frequency hopping CDMA method. The soft-orthogonal multi-access can be divided into two kinds of situations, orthogonal and quasi-orthogonal. Under the premise of not reducing spreading gain, the system BER performance is the same with DFH frequency division multiple access method in the orthogonal conditions. In the quasi-orthogonal case, the system is an interference limited system. For the problem of multi-access interference, this paper used a method of parallel multi-access interference cancellation technology, and verified the effectiveness of this technology by simulations.At final, this paper given a summary of the research, and proposed some directions of further research.更多还原