本文選題：5G + 頻譜效率�。� 參考：《北京交通大學》2017年碩士論文

【摘要】：隨著通信技術的飛速發(fā)展,5G時代已經(jīng)到來,對于通信系統(tǒng)的要求也隨之越來越高。更高的傳輸速率,超大規(guī)模的用戶容量,超低的通信時延,更好的用戶體驗,以及更高的頻譜利用率等等特點。本文主要針對提高頻譜效率,以及大規(guī)模用戶通信兩個場景進行討論。對于提高頻譜效率,正交頻分復用(OFDM)技術作為一種重要的多載波技術,不僅在4G系統(tǒng)中得到了廣泛使用,而且作為5G系統(tǒng)的重要候選波形之一仍然被眾多研究人員所推崇。但是與前幾代移動通信系統(tǒng)相比,5G系統(tǒng)設計時不僅要考慮移動寬帶業(yè)務,同時也會考慮未來對于海量機器連接以及高可靠低時延業(yè)務的支持。OFDM存在一些固有的缺點:比如對于頻率同步誤差,時間非同步,多普勒擴展等都比較敏感,所以如果對于未來更加多樣化的業(yè)務,更高的頻譜效率以及海量連接,如果繼續(xù)僅僅使用OFDM 一種波形技術是不夠的。因此本文主要針對于幾種新型的OFDM變形技術進行相關的研究比較與理論分析。同時基于LTE鏈路級平臺,分別在不同調制方式,用戶干擾、時延、多徑、峰值平均功率比/立方度量、誤差矢量幅度等幾個方面進行相關的仿真驗證。展示了在不同情境下,不同波形的優(yōu)缺點。此外,為了解決大規(guī)模用戶通信可能產(chǎn)生的擁堵問題,基于競爭的隨機接入機制便成為物理層對于未來5G中的一個研究熱點。在這種通信模式下,同時多用戶傳輸碰撞會導致信令的擾亂,進而使接收端無法正常的做接收信號的檢測。本文針對上述情景設計了一種新型結構的前導序列�？梢酝ㄟ^這種具有特定結構的前導序列來檢測碰撞用戶,同時在碰撞檢測的過程中也可以估計信道。本文對提出的前導序列方案在衰落信道,多徑信道以及異步等場景進行了理論分析與仿真驗證。仿真結果證實了本文提出方案的準確性與魯棒性。
[Abstract]:With the rapid development of communication technology, the requirement of communication system is becoming higher and higher. Higher transmission rate, large user capacity, ultra-low communication delay, better user experience, and higher spectrum efficiency. This paper mainly discusses the two scenarios of improving spectrum efficiency and large-scale user communication. As an important multicarrier technology, orthogonal Frequency Division Multiplexing (OFDM) is not only widely used in 4G systems, but also one of the important candidate waveforms for 5G systems. However, compared with previous generations of mobile communication systems, the design of the 5G system should not only consider mobile broadband services, At the same time, it will also consider that the future support for mass machine connections and high reliability and low delay traffic. OFDM has some inherent disadvantages: for example, frequency synchronization error, time non-synchronization, Doppler spread and so on are more sensitive. So it is not enough to use only one waveform technology of OFDM for more diversified services, higher spectral efficiency and mass connection in the future. Therefore, this paper mainly focuses on several new OFDM deformation technology related research and theoretical analysis. At the same time, based on the LTE link-level platform, simulations are carried out in different modulation modes, user interference, delay, multipath, peak-to-average power ratio / cubic metric, error vector amplitude and so on. The advantages and disadvantages of different waveforms in different situations are shown. In addition, in order to solve the problem of congestion caused by large-scale user communication, the competition-based random access mechanism has become a research focus in the physical layer for the future 5G. In this communication mode, simultaneous multi-user transmission collision will lead to the disturbance of signaling, which makes the receiver unable to detect the received signal normally. In this paper, a new structure leading sequence is designed for the above scenarios. The collision user can be detected by the preamble sequence with a specific structure, and the channel can be estimated during the collision detection process. In this paper, theoretical analysis and simulation of the proposed preamble scheme in fading channel, multipath channel and asynchronous channel are carried out. Simulation results show that the proposed scheme is accurate and robust.
【學位授予單位】：北京交通大學
【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：1817026