基于编码的协作通信技术研究

发布时间：2018-06-10 15:25

本文选题：协作通信 + 空时编码　；参考：《大连理工大学》2014年博士论文

【摘要】：协作通信技术利用多用户间的协作,共享彼此的资源,从而获得一定的空间分集增益,提高了系统的有效性和可靠性。协作通信技术不仅可以应用在蜂窝移动通信网中,还可以应用于传感器网络、无线自组织网络等多种场合,因此成为近年来通信领域研究的热点。本文在深入分析国内外研究工作的基础上,针对基于编码的协作通信技术展开研究,取得的主要成果如下：以移动通信系统下行链路为系统模型,提出了一种基于Alamouti空时编码的放大转发协作传输协议。首先,推导了瑞利衰落信道下M-PSK(M-ary Phase Shift Keying)调制时该系统的误符号率及高信噪比区域的渐进表达式。该方案能获得阶数为4的分集增益,有效提高了系统的可靠性。其次,推导了信源与中继的最佳功率分配闭式表达式,使系统总功率不变时系统的误符号率最小。研究了基于数字喷泉码的单中继协作传输技术,提出了两种编码方法。针对中继协作传输的计算复杂度和传输延迟问题,提出了一种分布式数字喷泉码——DLT码(Decomposed Luby Transform codes, DLT),设计了DLT码的两层编码度分布函数,并提出了一种基于DLT码的协作通信传输协议。与现有的无码率传输相比,该方案在各链路的丢包率较大时能有效减少中继节点的复杂度和系统传输延迟。针对误符号率的差错平台问题,提出了一种新的规则变量节点度LT码编码方法,该方法省去了现有方法中对变量节点度值表的排序、查找和更新过程,降低了编码复杂度,并利用对度分布的修正改善了解码瀑布区域,最后将该编码方法应用到单中继协作通信系统,并对误符号率进行了分析。与现有方法相比,该方法能节省系统编解码时间,在有效降低误符号率差错平台的同时,减少了译码所需信源平均传输次数。为了提高多中继无码率传输的频谱效率,提出了一种基于网络编码和中继选择的多中继无码率协作传输协议。该方法先建立成功译码的中继集合,利用中继选择策略选择最佳中继参与协作,与此同时源节点发送当前消息块与下一个数据块的网络编码信息,即可同时获得分集增益和网络编码增益。此外,将准静态瑞利衰落信道等效成相应的删除信道,推导了目的端译码需要的数据包数的概率质量函数和译码所需的平均传输次数,并讨论了中继集合大小对系统性能的影响。与现有的多中继无码率传输方案相比,该方法能有效减少系统平均传输次数,从而提高系统传输效率。
[Abstract]:Cooperative communication technology uses cooperation among multiusers and shares each other's resources to gain a certain spatial diversity gain and improves the effectiveness and reliability of the system. The cooperative communication technology can be applied not only in cellular mobile communication networks but also in sensor networks, wireless self-organizing networks and so on. On the basis of in-depth analysis of the research work at home and abroad, this paper studies the cooperative communication technology based on coding. The main achievements are as follows: using the downlink of the mobile communication system as the system model, a kind of amplified and forward cooperative transmission protocol based on Alamouti space-time coding is proposed. First, the error symbol rate and the high signal to noise ratio region of M-PSK (M-ary Phase Shift Keying) modulation in Rayleigh fading channel are derived. The scheme can obtain the diversity gain of the order of 4, which can effectively improve the reliability of the system. Secondly, the optimal power distribution closed expression of the source and the following is derived to make the total work of the system. The error rate of the system is the smallest when the rate is constant.
A single relay cooperative transmission technology based on digital fountain code is studied, and two coding methods are proposed. A distributed digital fountain code, DLT code (Decomposed Luby Transform codes, DLT), is proposed for the computation complexity and transmission delay of relay cooperative transmission. The two layer coding degree distribution function of the DLT code is designed and proposed. A cooperative communication transmission protocol based on DLT code is proposed. Compared with the existing non bit rate transmission, the scheme can effectively reduce the complexity of the relay nodes and the system transmission delay when the packet loss rate is large in each link. A new normalized variable node degree LT code coding method is proposed for the error platform error platform problem, which is saved by the method. The process of sorting, searching and updating the variable node degree table, reducing the coding complexity and using the correction of the degree distribution to improve the decoding waterfall area. Finally, the coding method is applied to the single relay cooperative communication system, and the false symbol rate is analyzed. Compared with the existing method, the method can save the system. In order to improve the frequency efficiency of the multi relay without code rate transmission, a kind of multi relay non bit rate cooperative transmission protocol based on network coding and relay selection is proposed. In order to improve the frequency efficiency of multi relay without code rate transmission, a relay set of successful decoding is first established. The relay selection strategy is used to select the best relay to participate in cooperation, while the source node sends the network coding information of the current message block and the next block of data, and the diversity gain and network coding gain can be obtained simultaneously. In addition, the quasi static Rayleigh fading channel is equivalent to the corresponding deletion channel, and the number of destination decode needs is derived. According to the probability mass function of the packet number and the average transmission times required for decoding, the effect of the relay set size on the system performance is discussed. Compared with the existing multi relay without code rate transmission scheme, this method can effectively reduce the average transmission times of the system and thus improve the transmission efficiency of the system.
【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN929.5

【参考文献】