本文選題：NOMA + 5G　； 參考：《西南交通大學》2017年碩士論文

【摘要】：隨著4G網(wǎng)絡的商用部署,5G移動通信技術的研究已經(jīng)如火如荼,面對5G海量連接、高頻譜效率和高容量的要求,非正交多址接入(NOMA)技術以其優(yōu)異的頻譜效率引起了業(yè)界廣泛地關注。NOMA技術引入功率域,實現(xiàn)多用戶功率域復用,在接收端通過串行干擾消除技術達到信號檢測的目的。由于NOMA技術在發(fā)送端主動引入了干擾,因而接收端的信號檢測成為NOMA關鍵技術點。本文針對NOMA系統(tǒng)下行鏈路信號的檢測以及接收機展開研究。論文首先對NOMA技術的基本原理做了介紹,并以兩個用戶的系統(tǒng)模型為例,定量驗證了相較于OFDMA系統(tǒng),NOMA系統(tǒng)帶來的性能增益。隨后論文介紹了功率分配和信號檢測兩個關鍵技術,以及MIMO技術相關原理。然后,利用模塊化的思想搭建NOMA系統(tǒng)下行鏈路的鏈路級仿真平臺�；谠撈脚_分別研究了單天線與多天線場景中Ideal SIC接收機、Symbol-level SIC接收機以及Codeword-level SIC接收機的接收性能。通過仿真分析發(fā)現(xiàn),在合理分配發(fā)送功率前提下,Codeword-level SIC接收機誤碼率性能與Ideal SIC接收機基本保持一致,而Symbol-level SIC接收機的性能則較差;隨著用戶間功率分配因子差值的增加,接收機的性能有所提高;提高用戶調(diào)制階數(shù),接收機對錯誤傳播更加敏感,性能變差。此外,在單天線場景中,以最大化加權和速率為功率分配準則,對功率分配算法進行了研究,得到結(jié)論功率分配因子取值不僅與用戶信噪比差值有關還與自身信噪比有關。在多天線場景中,研究了傳輸分集和空間復用兩種模式下接收機的性能,仿真結(jié)果表明,傳輸分集模式下接收機的性能均好于空間復用模式下接收機的性能。在多天線場景中,由于不僅存在用戶間的干擾,還存在流間干擾,使得Symbol-level SIC接收機對錯誤傳播更加敏感,導致Symbol-level SIC接收機的接收性能大幅度降低,故針對錯誤傳播(EP)問題對容量的影響進行了仿真分析,仿真結(jié)果表明EP會很大程度的影響系統(tǒng)容量。最后,引入了一種基于聯(lián)合檢測的算法,在接收端通過聯(lián)合星座圖直接檢測用戶信號,減少了干擾信號重建的過程。通過仿真發(fā)現(xiàn),該接收機性能遠遠優(yōu)于Symbol-level SIC接收機,且與Codeword-level SIC接收機相比,復雜度降低大約50%。
[Abstract]:With the commercial deployment of 4G network, the research of 5G mobile communication technology has been in full swing, facing the requirement of 5G mass connection, high spectrum efficiency and high capacity. Non-orthogonal multiple access (NOAA) technology has attracted wide attention because of its excellent spectral efficiency. Noma technology is introduced into power domain to realize multi-user power domain multiplexing and signal detection is achieved by serial interference cancellation at the receiver. Because the interference is introduced into the transmitter by NOMA technology, the signal detection at the receiving end becomes the key technology of NOMA. In this paper, the detection of downlink signal and receiver of NOMA system are studied. Firstly, the basic principle of NOMA technology is introduced, and the performance gains compared with OFDMA system are quantitatively verified by taking the system model of two users as an example. Then the paper introduces two key technologies of power allocation and signal detection, as well as the related principles of MIMO technology. Then, the link-level simulation platform of NOMA downlink is built by modularization. Based on this platform, the performance of Ideal SIC receiver Symbol-level SIC receiver and Codeword-level SIC receiver in single-antenna and multi-antenna scenarios are studied. The simulation results show that the BER performance of Codeword-level SIC receiver is basically the same as that of Ideal SIC receiver under the premise of reasonable allocation of transmission power, but the performance of Symbol-level SIC receiver is poor, and with the increase of power allocation factor difference between users, the BER performance of Codeword-level SIC receiver is basically the same as that of Ideal SIC receiver. The performance of the receiver is improved and the receiver is more sensitive to the error propagation and the performance becomes worse when the user modulation order is increased. In addition, in the single antenna scene, the maximum weighted sum rate is taken as the power allocation criterion, and the power allocation algorithm is studied. It is concluded that the power allocation factor is not only related to the difference of the user's SNR but also to its own signal-to-noise ratio (SNR). In the multi-antenna scene, the performance of receiver in transmission diversity mode and spatial multiplexing mode is studied. The simulation results show that the performance of receiver in transmission diversity mode is better than that in spatial multiplexing mode. In the multi-antenna scene, the Symbol-level SIC receiver is more sensitive to error propagation due to not only interuser interference but also inter-stream interference, which results in a significant decrease in the reception performance of the Symbol-level SIC receiver. Therefore, the effect of error Propagation (EPN) problem on the capacity is simulated and analyzed. The simulation results show that EP will greatly affect the capacity of the system. Finally, an algorithm based on joint detection is introduced to detect user signals directly through joint constellation at the receiving end, which reduces the reconstruction process of interference signals. The simulation results show that the performance of the receiver is much better than that of the Symbol-level SIC receiver, and the complexity of the receiver is reduced by about 50% compared with the Codeword-level SIC receiver.
【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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本文編號：1860349