SCMA系統(tǒng)在下行鏈路中的截止速率研究
發(fā)布時間：2019-03-11 08:05
【摘要】：稀疏碼分多址(Sparse Code Multiple Access,SCMA)是一種專門針對第五代移動通信系統(tǒng)(5G)提出的,非正交的,多址技術,該技術以低密度擴頻(Low Density Signature,LDS)多址技術為基礎,通過引入多維復數碼本/星座圖(Codebook/Constellation)的概念進一步獲得了額外的系統(tǒng)編碼與賦形增益。作為前景廣闊的非正交多址(Non-Orthogonal Multiple Access,NOMA)技術之一,SCMA系統(tǒng)能夠實現非常高的頻譜利用率。它不僅可以滿足未來5G通信網絡對海量用戶連接的需求,同時還能夠體現出高可靠、短時延、低功耗等多種優(yōu)點。本論文介紹了 SCMA系統(tǒng)的基本模型及其相關技術,對比于LDS-CDMA系統(tǒng),詳細介紹了 SCMA收發(fā)端原理和性能改進,并針對接收端檢測的消息傳遞算法(Message Passing Algorithm,MPA)的基本思想和運行原理進行了具體的講解。本文給出了幾種常見的SCMA碼本設計思想,主要應用于SCMA碼本母星座的設計。并通過對比SCMA的物理層模型,給出了 SCMA上/下行鏈路的相似性和差異性。SCMA系統(tǒng)容量的分析一直是相關課題的難度問題之一。我們通過分析其截止速率在一定程度上解決了相關問題。截止速率可以看作系統(tǒng)容量的下限,可用于表征系統(tǒng)可靠性,也可以用來判斷不同SCMA碼本的系統(tǒng)性能優(yōu)劣。本論文介紹了典型系統(tǒng)的截止速率及其重要相關參數,并進一步將其應用于SCMA系統(tǒng)的分析。為了增加SCMA系統(tǒng)截止速率分析的準確性,本論文給出了一種基于云狀分割(CloudPartition,CP)思想的分析方法,適用于SCMA下行鏈路。在此基礎上,對SCMA下行鏈路基于AWGN和Rayleigh兩種信道下的截止速率進行了理論分析。通過仿真結果,驗證了相關理論推導的實用性和準確性。
[Abstract]:Sparse Code Division multiple access (Sparse Code Multiple Access,SCMA) is a non-orthogonal, multi-access technology specifically designed for the fifth generation mobile communication system (5G), which is based on low density spread spectrum (Low Density Signature,LDS (LDSS) multiple access technology. By introducing the concept of multi-dimensional complex digital book / constellation graph (Codebook/Constellation), the additional system coding and shaping gain are obtained. As one of the promising non-orthogonal multiple access (Non-Orthogonal Multiple Access,NOMA) technologies, SCMA system can achieve very high spectrum efficiency. It can not only meet the needs of the future 5G communication network for massive user connections, but also show many advantages such as high reliability, short delay, low power consumption and so on. In this paper, the basic model of SCMA system and its related technologies are introduced. Compared with LDS-CDMA system, the principle and performance improvement of SCMA transceiver are introduced in detail, and the message passing algorithm (Message Passing Algorithm, for receiver detection is also introduced in detail. The basic idea and operation principle of MPA are explained in detail. In this paper, several common SCMA codebook design ideas are presented, which are mainly used in the design of SCMA codebook mother constellation. By comparing the physical layer model of SCMA, the similarity and difference of SCMA uplink / downlink are given. The analysis of SCMA system capacity has always been one of the difficult issues. We have solved the related problems to some extent by analyzing its cut-off rate. The cut-off rate can be regarded as the lower limit of the system capacity, can be used to characterize the system reliability, and can be used to judge the system performance of different SCMA codebooks. This paper introduces the cut-off rate of the typical system and its important parameters, and further applies it to the analysis of the SCMA system. In order to improve the accuracy of cut-off rate analysis for SCMA systems, this paper presents an analysis method based on cloud segmentation (CloudPartition,CP), which is suitable for SCMA downlink. On this basis, the cut-off rate of SCMA downlink based on AWGN and Rayleigh is analyzed theoretically. Through the simulation results, the practicability and accuracy of the relevant theoretical derivation are verified.
【學位授予單位】：西南交通大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TN929.5
本文編號：2438107
[Abstract]:Sparse Code Division multiple access (Sparse Code Multiple Access,SCMA) is a non-orthogonal, multi-access technology specifically designed for the fifth generation mobile communication system (5G), which is based on low density spread spectrum (Low Density Signature,LDS (LDSS) multiple access technology. By introducing the concept of multi-dimensional complex digital book / constellation graph (Codebook/Constellation), the additional system coding and shaping gain are obtained. As one of the promising non-orthogonal multiple access (Non-Orthogonal Multiple Access,NOMA) technologies, SCMA system can achieve very high spectrum efficiency. It can not only meet the needs of the future 5G communication network for massive user connections, but also show many advantages such as high reliability, short delay, low power consumption and so on. In this paper, the basic model of SCMA system and its related technologies are introduced. Compared with LDS-CDMA system, the principle and performance improvement of SCMA transceiver are introduced in detail, and the message passing algorithm (Message Passing Algorithm, for receiver detection is also introduced in detail. The basic idea and operation principle of MPA are explained in detail. In this paper, several common SCMA codebook design ideas are presented, which are mainly used in the design of SCMA codebook mother constellation. By comparing the physical layer model of SCMA, the similarity and difference of SCMA uplink / downlink are given. The analysis of SCMA system capacity has always been one of the difficult issues. We have solved the related problems to some extent by analyzing its cut-off rate. The cut-off rate can be regarded as the lower limit of the system capacity, can be used to characterize the system reliability, and can be used to judge the system performance of different SCMA codebooks. This paper introduces the cut-off rate of the typical system and its important parameters, and further applies it to the analysis of the SCMA system. In order to improve the accuracy of cut-off rate analysis for SCMA systems, this paper presents an analysis method based on cloud segmentation (CloudPartition,CP), which is suitable for SCMA downlink. On this basis, the cut-off rate of SCMA downlink based on AWGN and Rayleigh is analyzed theoretically. Through the simulation results, the practicability and accuracy of the relevant theoretical derivation are verified.
【學位授予單位】：西南交通大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TN929.5
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