本文選題：OFDM + MIMO��； 參考：《蘭州交通大學(xué)》2017年碩士論文

【摘要】：隨著4G技術(shù)的不斷完善,LTE網(wǎng)絡(luò)已在我國(guó)大規(guī)模商用。雖然LTE系統(tǒng)利用OFDM技術(shù)解決了小區(qū)內(nèi)干擾問(wèn)題,但其使用的同頻組網(wǎng)方案又給系統(tǒng)帶來(lái)了嚴(yán)重的小區(qū)間干擾。為了解決小區(qū)間干擾,3GPP制定了幾種干擾抑制方案,主要包括干擾隨機(jī)化、干擾消除和干擾協(xié)調(diào)三種,其中干擾協(xié)調(diào)因?yàn)槌杀镜?可實(shí)現(xiàn)性好,成為了干擾抑制技術(shù)的主流。干擾協(xié)調(diào)技術(shù)同樣也存在缺陷,尤其是用戶劃分算法會(huì)直接影響它的性能,因此,論文將提出一種新的用戶劃分算法,以期能完善干擾協(xié)調(diào)技術(shù)并減輕小區(qū)間干擾。論文首先介紹了LTE的網(wǎng)絡(luò)結(jié)構(gòu)和空中接口,隨后分析了OFDM技術(shù)和MIMO技術(shù),這兩種技術(shù)既是4G的核心,又決定了LTE網(wǎng)絡(luò)的抗干擾能力,其中OFDM技術(shù)能有效提高系統(tǒng)的頻帶利用率,并減輕多徑效應(yīng),而MIMO技術(shù)可明顯改善系統(tǒng)的吞吐量和可靠性。文中還介紹了幾種干擾抑制方式,其中包括了干擾協(xié)調(diào)技術(shù)中的SFR方案和FFR方案。由于SFR方案性能優(yōu)秀,且兼具靈活性和實(shí)用性,因此論文將以它為基礎(chǔ)對(duì)改進(jìn)算法進(jìn)行研究。為了測(cè)試改進(jìn)算法的性能,文中基于SFR技術(shù)搭建了LTE系統(tǒng)級(jí)仿真平臺(tái),平臺(tái)搭建分兩步完成,首先需要根據(jù)LTE協(xié)議規(guī)范確定仿真流程和基本參數(shù);隨后需要從基站、用戶、噪聲模型、業(yè)務(wù)模型、陰影衰落等方面進(jìn)行建模仿真。論文還列舉了系統(tǒng)的性能評(píng)估參數(shù),主要包括SINR和吞吐量?jī)煞N。仿真平臺(tái)搭建完成后,論文又研究了用戶數(shù)目變化時(shí)SFR技術(shù)的性能,此處得到的數(shù)據(jù),可與后文的仿真結(jié)果作對(duì)比。本文研究的重點(diǎn)是SFR中用戶分類算法對(duì)系統(tǒng)性能的影響,因此文中簡(jiǎn)要講解了幾種SFR中的用戶劃分算法,并詳細(xì)分析了它們的缺點(diǎn),原有的用戶劃分算法普遍使用固定閾值對(duì)用戶進(jìn)行一次性的分類,這種分類方式雖然簡(jiǎn)單,但準(zhǔn)確性不高。針對(duì)原有算法的不足,論文提出了一種同時(shí)考慮距離和SINR的用戶劃分新方案,改進(jìn)后的算法能準(zhǔn)確找到小區(qū)中受干擾最嚴(yán)重的中距用戶,并對(duì)他們進(jìn)行更合理的二次劃分。本文在提出新算法的同時(shí),也進(jìn)行了仿真驗(yàn)證,仿真結(jié)果表明,新的用戶劃分算法能更加有效地利用頻帶資源,同時(shí)提升邊緣用戶的吞吐量,論文據(jù)此得出了改進(jìn)算法比原有算法更優(yōu)秀的結(jié)論。
[Abstract]:With the continuous improvement of 4G technology, LTE network has been widely used in China.Although the LTE system uses OFDM technology to solve the problem of intra-cell interference, the scheme of co-frequency network has brought serious inter-cell interference to the system.In order to solve the problem of intercellular interference (3GPP), several interference suppression schemes have been developed, including randomization of interference, elimination of interference and coordination of interference, among which interference coordination has become the mainstream of interference suppression technology because of its low cost and good realizability.Interference coordination technology also has some defects, especially the user partition algorithm will directly affect its performance. Therefore, this paper will propose a new user partition algorithm in order to improve interference coordination technology and reduce inter-cell interference.This paper first introduces the network structure and air interface of LTE, then analyzes the OFDM technology and MIMO technology. These two technologies are not only the core of 4G, but also determine the anti-jamming ability of LTE network. OFDM technology can effectively improve the frequency band efficiency of the system.And reduce the multipath effect, and MIMO technology can obviously improve the throughput and reliability of the system.Several interference suppression methods are also introduced, including SFR scheme and FFR scheme in interference coordination technology.Due to the excellent performance, flexibility and practicability of the SFR scheme, this paper will study the improved algorithm based on it.In order to test the performance of the improved algorithm, this paper builds a LTE system-level simulation platform based on SFR technology. The platform is built in two steps. Firstly, the simulation flow and basic parameters need to be determined according to the LTE protocol specification.Noise model, traffic model, shadow fading and other aspects of modeling and simulation.The performance evaluation parameters of the system are listed, including SINR and throughput.After the completion of the simulation platform, the performance of SFR technology is studied when the number of users changes. The data obtained here can be compared with the simulation results.This paper focuses on the impact of user classification algorithms in SFR on system performance. Therefore, several user partition algorithms in SFR are briefly explained, and their shortcomings are analyzed in detail.The original user partition algorithm generally uses fixed threshold to classify users at one time. Although this classification method is simple, but the accuracy is not high.In view of the shortcomings of the original algorithm, a new user partition scheme considering both distance and SINR is proposed. The improved algorithm can accurately find the most seriously disturbed users in the cell, and give them a more reasonable quadratic partition.In this paper, the new algorithm is proposed, and the simulation results show that the new user partition algorithm can make more effective use of frequency band resources and improve the throughput of edge users.Based on this, the conclusion that the improved algorithm is better than the original algorithm is obtained.
【學(xué)位授予單位】：蘭州交通大學(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)：1756313