本文選題：傳輸時間間隔 + 子幀長度　； 參考：《北京交通大學(xué)》2017年碩士論文

【摘要】：更高的數(shù)據(jù)速率,更低的數(shù)據(jù)延遲一直都是無線通信系統(tǒng)演進(jìn)的目標(biāo),也是第四代移動通信技術(shù)(4th Generation,4G)相對于上一代移動無線通信技術(shù)的顯著優(yōu)勢。而與4G相比,第五代移動通信技術(shù)(5th Generation,5G)更是明確提出了要進(jìn)一步增大用戶數(shù)據(jù)峰值速率、減小空中接口時延。作為4G和5G之間的過渡階段,長期演進(jìn)技術(shù)升級版后續(xù)(Long Term Evolution-Advanced Pro,LTE-APro)的目標(biāo)之一就是在4G的基礎(chǔ)上進(jìn)一步減小用戶時延,增大系統(tǒng)吞吐量,為5G的到來做好鋪墊�？紤]到縮減用戶時延可以提高無線資源的利用效率,提高控制信令的傳輸速度,減小呼叫設(shè)置或承載設(shè)置時間,而傳輸時間間隔(Transmission Time Interval,TTI)是用戶傳輸時延的重要組成部分,本文提出了通過優(yōu)化TTI來減小用戶傳輸時延的方法。雖然第三代合作伙伴計(jì)劃(3rd Generation Partnership Project,3GPP)提出的各種預(yù)調(diào)度策略可以減小一部分時延,但是不能很好地兼顧效率問題,本文提出的通過優(yōu)化TTI減小用戶傳輸時延的方法就不存在效率問題,因此,本文的研究工作非常有必要。為了優(yōu)化TTI,降低系統(tǒng)傳輸時延、提高系統(tǒng)吞吐量,本文主要做了兩階段的工作。第一階段,在長期演進(jìn)(Long Term Evolution,LTE)系統(tǒng)中,TTI在時間長度上對應(yīng)著一個子幀的長度,因此可以通過優(yōu)化子幀結(jié)構(gòu)的方法來優(yōu)化TTI。在對物理層信道和信號做出適應(yīng)性改進(jìn),保證后向兼容性的前提下,將LTE下行鏈路子幀長度從14個正交頻分復(fù)用技術(shù)(Orthogonal Frequency Division Multiplexing,OFDM)符號分別縮減為7個OFDM符號和2個OFDM符號。并在靜態(tài)控制開銷的前提下,通過設(shè)置最大調(diào)度用戶數(shù)目以及數(shù)據(jù)包大小等條件,進(jìn)行了仿真分析,可得在信道條件良好時,子幀長度越短,即TTI越小,系統(tǒng)時延改善越明顯。第二階段的工作在動態(tài)控制開銷的前提下展開,分為兩部分。第一部分,通過設(shè)置數(shù)據(jù)包大小、慢啟動閾值等條件,進(jìn)行了仿真分析。在信道條件良好時,TTI越小,系統(tǒng)性能增益越大。但是由于TTI越小,對硬件的要求越高,對規(guī)范協(xié)議的改動越大,實(shí)現(xiàn)難度也越大。在第二部分工作中,為了兼顧系統(tǒng)性能與實(shí)現(xiàn)難度,即在子幀長度為7個OFDM符號的情況下實(shí)現(xiàn)最大的系統(tǒng)增益,本文又提出了優(yōu)化上行鏈路接入時延和混合自動重傳請求(Hybrid Automatic Repeat Request,HARQ)肯定應(yīng)答/否定應(yīng)答(Acknowledgement/Non-acknowledgement,ACK/NACK)往返時延的方法。仿真證明,在采用此種方法后,子幀長度為7個OFDM符號時,以傳統(tǒng)TII的系統(tǒng)性能作為參考量,對于系統(tǒng)低負(fù)載情況下的小區(qū)邊緣用戶和中心用戶,系統(tǒng)時延可以減少45.6%和40.6%,優(yōu)于沒有采用此方法的子幀長度為2個OFDM符號的系統(tǒng)性能表現(xiàn),兼顧了系統(tǒng)性能增益與實(shí)現(xiàn)難度。
[Abstract]:Higher data rates and lower data delays have been the goal of the evolution of the wireless communication system and the significant advantage of the fourth generation 4th Generation (4G) relative to the previous generation of mobile wireless communication technology. Compared with the 4G, the fifth generation mobile communication technology (5th Generation, 5G) is more clearly proposed to increase. User data peak rate, reducing air interface delay. As a transition phase between 4G and 5G, one of the goals of Long Term Evolution-Advanced Pro, LTE-APro is to further reduce user delay on the basis of 4G, increase system throughput, paving for the arrival of 5G. Considering the reduction of users Time delay can improve the utilization efficiency of wireless resources, improve the transmission speed of the control signaling, reduce the call setting or load setting time, and the Transmission Time Interval (TTI) is an important part of the user's transmission delay. This paper proposes a method to reduce the transmission delay of the user through the optimization of TTI. Although the third generation of the method is used to reduce the time delay of the user. The various pre scheduling strategies proposed by 3rd Generation Partnership Project (3GPP) can reduce a part of the time delay, but can not give consideration to the efficiency problem well. The method proposed in this paper does not exist the efficiency problem by optimizing the method of reducing the transmission delay of the user by TTI. Therefore, the research work of this paper is very necessary. In order to reduce the TTI transmission delay and improve the system throughput, this paper mainly does two stages of work. In the first stage, in the Long Term Evolution (LTE) system, TTI corresponds to the length of a subframe in the length of time. Therefore, the method of optimizing the subframe structure to optimize the TTI. in the physical layer channel and signal can be optimized. On the premise of adaptive improvement and ensuring backward compatibility, the LTE downlink subframe length is reduced from 14 orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM) symbols to 7 OFDM symbols and 2 OFDM symbols respectively. Under the premise of static control overhead, the number and number of the maximum scheduling users are set by setting the number and number of the maximum scheduling. According to the package size and other conditions, the simulation analysis is carried out. When the channel condition is good, the shorter the sub frame length is, the smaller the TTI is, the more obvious the improvement of the system delay. The second stage is divided into two parts under the premise of dynamic control overhead. The first part, the simulation analysis is carried out by setting the packet size, the slow start threshold and so on. When the channel conditions are good, the smaller the TTI, the greater the system performance gain. But the smaller the TTI, the higher the requirement for the hardware, the greater the change to the specification protocol, the greater the difficulty. In the second part, the maximum system increase is achieved in order to give consideration to the system performance and the realization of the difficulty, that is, in the case of the subframe length of 7 OFDM symbols. This paper also proposes a method to optimize the uplink access delay and the Hybrid Automatic Repeat Request (HARQ) affirmative response / negative response (Acknowledgement/Non-acknowledgement, ACK/NACK) round-trip delay. The simulation proves that, when this method is adopted, the length of the subframe is 7 OFDM symbols, and the system is based on the traditional TII. As a reference, the system delay can be reduced by 45.6% and 40.6% for small cell edge users and central users under low load conditions. It is superior to the system performance performance of 2 OFDM symbols without using the subframe length of this method, which takes into account the performance gain and difficulty of the system.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN929.5

【參考文獻(xiàn)】

相關(guān)期刊論文 前4條

1 刁興玲;;高通:推進(jìn)LTE-A Pro,引領(lǐng)5G之路[J];通信世界;2016年13期

2 劉瑞強(qiáng);;LTE-Advanced Pro關(guān)鍵技術(shù)及其演進(jìn)概述[J];電信網(wǎng)技術(shù);2015年11期

3 陳裕通;魏國廷;;LTE系統(tǒng)RRC層RRC連接建立過程研究[J];內(nèi)江科技;2014年02期

4 張占全;王天石;;分組數(shù)據(jù)業(yè)務(wù)模型在三代移動通信系統(tǒng)中的研究[J];科技風(fēng);2009年07期

相關(guān)會議論文 前1條

1 劉翔;李川;;LTE TDD與FDD制式技術(shù)對比與融合組網(wǎng)策略分析[A];四川省通信學(xué)會2014年學(xué)術(shù)年會論文集[C];2014年

相關(guān)碩士學(xué)位論文 前6條

1 張力;低成本MTC室內(nèi)覆蓋增強(qiáng)技術(shù)研究[D];重慶大學(xué);2014年

2 張娜;LTE隨機(jī)接入中最優(yōu)接入控制算法的研究[D];武漢理工大學(xué);2013年

3 郭瑞龍;LTE系統(tǒng)覆蓋性能的研究[D];內(nèi)蒙古大學(xué);2012年

4 王顯賀;3G移動數(shù)據(jù)業(yè)務(wù)中HTTP和FTP業(yè)務(wù)建模研究與實(shí)現(xiàn)[D];北京郵電大學(xué);2012年

5 楊姍;LTE-A CoMP系統(tǒng)的關(guān)鍵技術(shù)研究及性能分析[D];北京郵電大學(xué);2012年

6 劉朝陽;LTE下行鏈路仿真平臺設(shè)計(jì)實(shí)現(xiàn)及物理層關(guān)鍵技術(shù)分析[D];西安科技大學(xué);2011年

，

本文編號：1999517