免信令的上行非正交多址方法研究

发布时间：2018-01-23 23:49

本文关键词： 免信令传输非正交多址技术大连接支持稀疏恢复扩展码设计　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：在满足了人与人之间的通信后,物联网为无线通信的发展注入了新的活力。移动互联网和物联网已经成了发展第五代移动通信(5G)系统的两大驱动力。为了满足5G通信的通信需求,一个新型的多址技术至关重要。第一代移动通信(1G)到第四代移动通信(4G)系统上行通信采用的都是正交的多址技术,面对5G通信的新要求,这些正交多址技术的不足日益凸显出来,包括频谱效率低、大连接支持能力差等。为此,通信的研究和标准制定工作对可以提供更高频谱效率、更高接入量的非正交多址技术给予了重视。目前正在研究的上行非正交多址技术包括稀疏码分多址(SCMA,sparse code multipleaccess)、多用户共享接入(MUSA,multi-usershared access)以及图样分割多址(PDMA,pattern division multiple access)等。相对于正交的多址技术,这些非正交的多址技术可以极大提高系统的频谱效率和大连接支持能力。不过这些非正交多址技术依然存在一些需要克服的技术困难。其次,除了 MUSA,它们在提出之初并没有特别考虑通信用户的多址接入过程。如果5G系统同样采用以往系统中基于竞争的多址接入协议,则会面临繁重的接入信令负担,甚至产生信令风暴。这种情况下,即使是非正交多址技术的优势也会被严重削弱。针对上述问题,论文提出了免信令的上行非正交多址方法,并对其中的关键问题开展了研究。具体地,论文的主要内容包括:1)提出了免信令的上行非正交多址方法提出的方法中,数据包首先进行扩展码扩展处理,其结果是增加数据包的符号数量,扩展后的数据包再通过系统分配好的时频资源进行传输,接收端进行多天线接收并完成数据的恢复。该过程中,用户传输数据包的时频资源早在用户注册网络,或者第一次有数据包发送,或者系统为了平衡负载而进行资源的再分配时就已经给定,系统动态而频繁的无线资源分配并不需要。因此,所提方法可以免去接入信令开销。同时,通过非正交扩展,系统允许相当多的用户使用相同的时频资源。因此相对于正交的多址方法,方法在频谱效率、大连接的支持能力上也有非常明显的优势。2)免信令上行非正交多址方法的数据恢复根据提出的方法,同时考虑用户传输行为的稀疏性,论文建立了块稀疏的非正交多址模型。由于采用的是免接入过程的多址方法,哪些用户有传输数据包接收端预先并不知道。因此,数据恢复的任务包括检测有传输数据包的用户和解调这些用户发送的数据符号。在这个问题上,论文借鉴稀疏恢复中迭代的块正交匹配追踪(BOMP,block orthogonal matching pursuit)算法提出了 PICNBOMP(perfect interference cancellation based and normalized BOMP)算法。PICNBOMP 的主要思想是将通信信号中常见的错误纠检错编码融入到迭代算法中进行完美干扰消除,由此获得了提高数据恢复准确性和降低恢复复杂度的双重优势。特别地,该算法体现的思路具有普适性,其对于控制迭代算法的误差传播非常有效。只要消息具有纠检错编码结构以及多个消息之间存在干扰,它们的迭代恢复即可借鉴论文中提高算法的思想。3)免信令上行非正交多址方法的扩展码设计所提方法中,扩展码至关重要,它的作用包括携带用户身份信息、直接影响用户传输数据之间的干扰和方法的实现复杂度等。扩展码以预编码矩阵的形式出现在方法中。基于PICNBOMP算法,论文从稀疏恢复算法用户检测和符号解调的准确性角度出发对预编码矩阵应该满足的条件进行了分析研究。分析的结果表明列正交的预编码矩阵有利于提高恢复准确性。论文接着给出了三种列正交的预编码矩阵设计实例,其中非常稀疏的正交预编码矩阵还可以极大降低方法的实现复杂度。为了进一步降低稀疏恢复中用户检测的复杂度,论文设计了结构化的预编码矩阵。相对于已有的非正交多址技术中的码本/序列/图样设计,论文提出的非正交多址方法中的预编码矩阵设计非常简单,随机产生的正交的预编码矩阵就可以获得相当不错的多址性能。
[Abstract]:To meet the communication between people and things has injected new vitality to the development of wireless communication. The mobile Internet and the Internet of things has become the development of the fifth generation mobile communication system (5G) of the two major driving force. In order to meet the communication needs of 5G communication, a new multiple access technology is very important. The first generation of mobile communication (1G) to the fourth generation mobile communication system (4G) uplink communication are using orthogonal multiple access technology, facing the new requirements of 5G communication, lack of these orthogonal multiple access technology has become increasingly prominent, including low spectrum efficiency, high connection support ability. Therefore, research and communication standards the work can provide higher spectrum efficiency, non orthogonal multiple access technology with higher access amount given attention. Uplink is currently studying the non orthogonal multiple access techniques including sparse CDMA (SCMA, sparse code, multipleaccess) with Users share access (MUSA, multi-usershared access) and multiple access pattern segmentation (PDMA, pattern division multiple access). Compared with the orthogonal multiple access technology, the non orthogonal multiple access technology can greatly improve the spectrum efficiency and high connection support. However these non orthogonal multiple access technology, there are still some need to overcome technical difficulties. Secondly, in addition to MUSA, they are not particularly considering the multiple access communication of users in the process put forward at the beginning. If the 5G system also uses multiple access protocol based on competition in previous system, will face heavy burden access signaling, and even signaling storm. In this case, even if it is non orthogonal multiple access technology advantage will be seriously impaired. Aiming at the above problems, the proposed uplink signaling free non orthogonal multiple access method, and the key problems are studied. Specifically, the main contents of this paper include: 1) proposed uplink signaling method proposed free non orthogonal multiple access method, data packet first spreading code is processed, the result is to increase the number of symbol data packets, packet expanded through the system to allocate good time-frequency resources for transmission, reception the end of multi antenna receiving and data recovery. In this process, the user data packet transmission time frequency resource in network user registration, or the first packet, or the system of resource redistribution in order to balance the load and has been given, the radio resource allocation system dynamic and frequent. So don't need, the proposed method can be removed from the access signaling overhead. At the same time, the non orthogonal expansion system allows a considerable number of users use the same time-frequency resources. So compared with the method of orthogonal multiple access methods, in the spectrum efficiency Rate, ability to support connection has the obvious advantages of.2 signaling) free uplink non orthogonal multiple access method for data recovery based on the proposed method, considering the sparsity of user transmission behavior, the non orthogonal multiple access model block sparse. Due to the use of the multiple access method of free access process which users transmit data packets, the receiver is not known in advance. Therefore, the data recovery tasks include detection of transmitted data symbols user data packet transmission and demodulation of these users. In this issue, based on the block orthogonal sparse recovery iterative matching pursuit (BOMP block, orthogonal matching pursuit) algorithm is proposed for PICNBOMP (perfect interference cancellation based and normalized BOMP) algorithm.PICNBOMP is the communication signals in common error correcting encoding into iterative algorithm In perfect interference, thus obtained to improve accuracy and reduce the data recovery recovery advantages complexity. Especially, the algorithm embodies the ideas of universality, it is very effective to control the error propagation algorithm. As long as the message is there is interference between EDAC encoding structure and a plurality of messages, their iterative you can learn to improve the recovery algorithm.3 in this thesis) method proposed non orthogonal spreading code free signaling uplink multiple access methods, the spreading code is essential, its effects include carrying the user identity information, directly influences the realization method between user interference and data transmission. The complexity of spreading codes to pre encoding matrix appear in the method. Based on the PICNBOMP algorithm, the restoration algorithm of user detection and symbol demodulation accuracy from the sparse point of view of the precoding matrix should be full The condition was analyzed. The analysis results show that column orthogonal precoding matrix can improve the recovery accuracy. Then the paper gives the three column orthogonal precoding matrix design examples, including orthogonal pre encoding very sparse matrix method also can greatly reduce the complexity of implementation. In order to further reduce the complexity of sparse recovery user detection, this paper designed a structured precoding matrix. Compared with the codebook / non orthogonal multiple access technology has been in the series / pattern design, the design of precoding matrix non orthogonal multiple access method proposed in the paper is very simple, orthogonal random precoding matrix can obtain multiple access performance good.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN929.5

【相似文献】