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

【摘要】：隨著通信技術(shù)的飛速發(fā)展,5G時(shí)代已經(jīng)到來,對(duì)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(shí)延,更好的用戶體驗(yàn),以及更高的頻譜利用率等等特點(diǎn)。本文主要針對(duì)提高頻譜效率,以及大規(guī)模用戶通信兩個(gè)場(chǎng)景進(jìn)行討論。對(duì)于提高頻譜效率,正交頻分復(fù)用(OFDM)技術(shù)作為一種重要的多載波技術(shù),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(dòng)通信系統(tǒng)相比,5G系統(tǒng)設(shè)計(jì)時(shí)不僅要考慮移動(dòng)寬帶業(yè)務(wù),同時(shí)也會(huì)考慮未來對(duì)于海量機(jī)器連接以及高可靠低時(shí)延業(yè)務(wù)的支持。OFDM存在一些固有的缺點(diǎn):比如對(duì)于頻率同步誤差,時(shí)間非同步,多普勒擴(kuò)展等都比較敏感,所以如果對(duì)于未來更加多樣化的業(yè)務(wù),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(shù)是不夠的。因此本文主要針對(duì)于幾種新型的OFDM變形技術(shù)進(jìn)行相關(guān)的研究比較與理論分析。同時(shí)基于LTE鏈路級(jí)平臺(tái),分別在不同調(diào)制方式,用戶干擾、時(shí)延、多徑、峰值平均功率比/立方度量、誤差矢量幅度等幾個(gè)方面進(jìn)行相關(guān)的仿真驗(yàn)證。展示了在不同情境下,不同波形的優(yōu)缺點(diǎn)。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(jìng)爭(zhēng)的隨機(jī)接入機(jī)制便成為物理層對(duì)于未來5G中的一個(gè)研究熱點(diǎn)。在這種通信模式下,同時(shí)多用戶傳輸碰撞會(huì)導(dǎo)致信令的擾亂,進(jìn)而使接收端無法正常的做接收信號(hào)的檢測(cè)。本文針對(duì)上述情景設(shè)計(jì)了一種新型結(jié)構(gòu)的前導(dǎo)序列�？梢酝ㄟ^這種具有特定結(jié)構(gòu)的前導(dǎo)序列來檢測(cè)碰撞用戶,同時(shí)在碰撞檢測(cè)的過程中也可以估計(jì)信道。本文對(duì)提出的前導(dǎo)序列方案在衰落信道,多徑信道以及異步等場(chǎng)景進(jìn)行了理論分析與仿真驗(yàn)證。仿真結(jié)果證實(shí)了本文提出方案的準(zhǔn)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(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN929.5

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本文編號(hào)：1817026