删除信道网络喷泉码分析及优化设计
发布时间：2018-07-25 15:53
【摘要】：宽带通信技术发展至今,利用互联网进行工作交流已成为人们日常生活不可或缺的一部分。用户数量和网络数据流通量的急速增长对网络传输的速度和可靠性提出了新的要求。为了提高网络的传输效率和系统整体的吞吐率,大量的学者致力于对网络通信技术各个领域的研究。从而涌现出了大量的新兴技术,数字喷泉编码技术和网络编码技术就是其中较为有效的两种。两者分别利用时间和空间资源以达到提高网络传输效率的目的。而网络喷泉码将两者结合,更加充分地利用时间空间两维资源,实现网络吞吐率的最大化。网络喷泉码作为一种新颖的性能良好的编码技术,为网络大数据的实时传输和存储提供了新的有效手段。本文也将在传统喷泉码的基础上,利用网络编码技术,产生性能更好的网络喷泉码。研究主要围绕着LT码展开。针对直传网络、广义协作分布式网络和多用户的蝴蝶型网络提出各模型下网络喷泉码对应的度分布描述和度分布设计方法。主要工作如下:1.针对点对点直传模型,在删除信道下对LT(Luby Transform,LT)码的渐进性能进行推导,得出其下限,并通过仿真证明此下限与渐进性能匹配。利用LT码的渐进性能与其下限,得出以最小复杂度为目标的优化模型LP 1和LP 2。新的以最小复杂度为目标的优化模型对简单直传情况下的LT码有着良好的优化效果,得到的度分布的性能优于传统的RSD(Robust Soliton Distribution,RSD)分布。特别是LP 2模型,它的计算复杂度较低,而且优化效果明显,对开销和理想误码率的控制进一步增强,在我们为模型设置的开销参数之内就能达到所设置的误码率。将上述LT码在直传模型下的各种性质与优化模型向SLT(Systematic Luby Transform,SLT)码进行了推广,利用“与或树”分析的方法,得到SLT码的渐进性能并提出针对SLT码的优化模型SLP 1和SLP 2。仿真证明优化所得的度分布性能优于经典的RSD分布与TDD分布,且SLP 2对性能的控制性仍然存在。2.对协作分布式数字喷泉码进行了研究。首先在广义分布式数字喷泉码的基础上,增加直传的路径,建立了协作分布式数字喷泉码模型,并给出此模型下各信源的多元度分布描述。然后,使用与或树分析方法对此模型的渐进性能和下限进行推导,将直传模型下的最小复杂度的优化模型推广到此模型下,为协作分布式数字喷泉码度分布的实例化设计提供了思路。最后,使用改进的差分进化算法改进原有优化算法,提出新的针对两信源以上的更加高效的优化求解方法,从而实现了复杂模型下LT码的实例化。3.本文进一步对多用户的网络模型展开研究。针对最简单的蝴蝶型网络,给出各信源针对各个目的节点的度分布,渐进性能和其下限。之后,我们定义了新的网络数字喷泉码性能描述指标——渐进吞吐率,并使用一定的近似处理,得到吞吐率的表达式。仿真证明,此吞吐率的表达式适用于大多数渐进误码率曲线成“Z”字型的度分布,且真实值与理论值的差距极小。根据上述吞吐率的表达式,我们为蝴蝶型网络设计了最大吞吐率的优化模型以达到数字喷泉码的实例化,为蝴蝶型网络数字喷泉码提供了实例化设计。
[Abstract]:With the development of broadband communication technology, the use of the Internet has become an indispensable part of people's daily life. The rapid growth of the number of users and the flow of network data has put forward new requirements for the speed and reliability of network transmission. In order to improve the transmission efficiency of the network and the overall throughput of the system, a large number of studies have been made. A large number of new technologies are emerging, and digital fountain coding and network coding are two more effective. Both of them use time and space resources to improve the efficiency of network transmission. Using two dimensional resources in time and space to maximize the network throughput, the network fountain code, as a novel coding technique with good performance, provides a new and effective means for real-time transmission and storage of large data in the network. This paper will also use the network coding technology to produce a better network based on the traditional fountain code. The research mainly focuses on the LT code. Aiming at the direct transmission network, the generalized cooperative distributed network and the multi user butterfly network, the degree distribution description and degree distribution design method corresponding to the network fountain codes under each model are proposed. The main work is as follows: 1. for the point to point direct mode, the LT (Luby Transform, LT) code under the deleted channel The asymptotic performance is derived and its lower limit is obtained. Through the simulation, it is proved that the lower limit is matched with the progressive performance. Using the gradual performance and the lower limit of LT code, the optimization model, LP 1 and LP 2., which aims at the minimum complexity, has a good optimization effect on the LT code under the single direct transmission condition. The performance of the obtained degree distribution is better than the traditional RSD (Robust Soliton Distribution, RSD) distribution. Especially, the LP 2 model has a low computational complexity, and the optimization effect is obvious. The control of the cost and the ideal bit error rate is further enhanced, and the bit error rate set can be reached within the overhead parameters set for the model. The properties and optimization models of LT codes are generalized to SLT (Systematic Luby Transform, SLT) codes. The asymptotic performance of SLT code is obtained by means of "or tree" analysis, and the optimization model of SLT code, SLP 1 and SLP 2., is proposed. The degree distribution performance of the optimization model, SLP 1 and SLP 2., is better than the classic RSD distribution and TDD. Distribution, and the controllability of SLP 2 for performance still exists in the research of cooperative distributed digital fountain code. First, on the basis of the generalized distributed digital fountain code, a cooperative distributed digital fountain code model is established by adding the direct transmission path, and the multivariate distribution of each source is described under this model. Then, the use of and or tree are used. The asymptotic performance and the lower limit of the model are derived, and the optimization model of the minimum complexity under the direct transmission model is extended to this model, which provides an idea for the instantiation design of the cooperating distributed digital fountain code distribution. Finally, the improved differential evolution algorithm is used to improve the original optimization algorithm, and a new two letter is proposed. The more efficient optimization solving method above the source, thus realizing the instantiation of LT code under the complex model.3. this paper further studies the multi user network model. For the simplest butterfly type network, the degree distribution, the progressive performance and the lower limit of each source are given for each destination node. The performance description of the word fountain code is the progressive throughput rate, and the expression of the throughput rate is obtained by using certain approximate processing. The simulation shows that the expression of the throughput is suitable for the degree distribution of most progressive bit error rate curves into the "Z" type, and the difference between the real value and the theoretical value is very small. Butterfly network designs the optimization model of the maximum throughput to achieve the instantiation of the digital fountain code, and provides instantiation design for the butterfly network digital fountain code.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN911.22
本文编号：2144309
[Abstract]:With the development of broadband communication technology, the use of the Internet has become an indispensable part of people's daily life. The rapid growth of the number of users and the flow of network data has put forward new requirements for the speed and reliability of network transmission. In order to improve the transmission efficiency of the network and the overall throughput of the system, a large number of studies have been made. A large number of new technologies are emerging, and digital fountain coding and network coding are two more effective. Both of them use time and space resources to improve the efficiency of network transmission. Using two dimensional resources in time and space to maximize the network throughput, the network fountain code, as a novel coding technique with good performance, provides a new and effective means for real-time transmission and storage of large data in the network. This paper will also use the network coding technology to produce a better network based on the traditional fountain code. The research mainly focuses on the LT code. Aiming at the direct transmission network, the generalized cooperative distributed network and the multi user butterfly network, the degree distribution description and degree distribution design method corresponding to the network fountain codes under each model are proposed. The main work is as follows: 1. for the point to point direct mode, the LT (Luby Transform, LT) code under the deleted channel The asymptotic performance is derived and its lower limit is obtained. Through the simulation, it is proved that the lower limit is matched with the progressive performance. Using the gradual performance and the lower limit of LT code, the optimization model, LP 1 and LP 2., which aims at the minimum complexity, has a good optimization effect on the LT code under the single direct transmission condition. The performance of the obtained degree distribution is better than the traditional RSD (Robust Soliton Distribution, RSD) distribution. Especially, the LP 2 model has a low computational complexity, and the optimization effect is obvious. The control of the cost and the ideal bit error rate is further enhanced, and the bit error rate set can be reached within the overhead parameters set for the model. The properties and optimization models of LT codes are generalized to SLT (Systematic Luby Transform, SLT) codes. The asymptotic performance of SLT code is obtained by means of "or tree" analysis, and the optimization model of SLT code, SLP 1 and SLP 2., is proposed. The degree distribution performance of the optimization model, SLP 1 and SLP 2., is better than the classic RSD distribution and TDD. Distribution, and the controllability of SLP 2 for performance still exists in the research of cooperative distributed digital fountain code. First, on the basis of the generalized distributed digital fountain code, a cooperative distributed digital fountain code model is established by adding the direct transmission path, and the multivariate distribution of each source is described under this model. Then, the use of and or tree are used. The asymptotic performance and the lower limit of the model are derived, and the optimization model of the minimum complexity under the direct transmission model is extended to this model, which provides an idea for the instantiation design of the cooperating distributed digital fountain code distribution. Finally, the improved differential evolution algorithm is used to improve the original optimization algorithm, and a new two letter is proposed. The more efficient optimization solving method above the source, thus realizing the instantiation of LT code under the complex model.3. this paper further studies the multi user network model. For the simplest butterfly type network, the degree distribution, the progressive performance and the lower limit of each source are given for each destination node. The performance description of the word fountain code is the progressive throughput rate, and the expression of the throughput rate is obtained by using certain approximate processing. The simulation shows that the expression of the throughput is suitable for the degree distribution of most progressive bit error rate curves into the "Z" type, and the difference between the real value and the theoretical value is very small. Butterfly network designs the optimization model of the maximum throughput to achieve the instantiation of the digital fountain code, and provides instantiation design for the butterfly network digital fountain code.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN911.22
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