臺灣博碩士論文加值系統

在長期演進系統(Long Term Evolution ; LTE)中由於OFDMA技術的實現可以消除大部分細胞(Cell)內的干擾，但是由於各個Cell間並不知道鄰近Cell資源分配情形，因此很容易在Cell的邊緣處產生干擾，即所謂的細胞間干擾(inter cell interference ; ICI)，此種情形使得Cell邊緣的用戶(User Equipment ;UE)遭受嚴重的干擾，導致邊緣用戶的訊號品質降低影響系統產能。因此許多論文提出各種方法來解決ICI的問題，其中較多人討論的方法如：部份頻率重複使用(Fraction Frequency Reuse ; FFR)、軟頻率重複使用(Soft Frequency Reuse ; SFR)。
然而FFR、SFR是通過限制外部區域可用的頻寬資源來避免對鄰近的Cell造成干擾，因此對整個Cell而言可利用的頻寬資源會因此減少，而且頻寬資源的分配並沒有依據各服務區域內的人數進行改變，如此一來當Cell內各服務區域內的用戶數改變時，其整體資源的利用率會因此降低，為了提昇資源利用率故提出了動態調整頻寬資源的FFR和SFR。
雖然動態調整頻寬資源的確可以改善資源利用率降低的情況，但由於調整時仍需避免ICI的產生，使得一個Cell需要進行調整時必須與鄰近的Cell一起調整，如此一來勢必要花上大量的時間進行資料的交換並且需要經過大量的演算才能達到最佳化。因此我們提出一個簡單、快速的演算法使得在動態調整頻寬資源時，不需與鄰近的Cell一起調整頻寬資源仍可以避免ICI。

In the LTE system, the bandwidth will be divided by the time and frequency into many resource blocks, then user can use these different resource blocks to transmit data. Thus LTE can avoid most intra cell interference. However, due to the cell doesn’t know what the situation of resource allocation by other neighboring cell, they will make interference to each other easily, called inter cell interference. In this situation, the user who is on the cell edge will suffer more interference. Thus, there are many papers proposed to solve the inter cell interference (ICI) problem, such as: FFR (Fractional Frequency Reuse) and SFR (Soft Frequency Reuse).
Although these methods can avoid interference to nearby cell through restricting the available frequency resources in their own cell’s sectors, the available resources will be reduced. In addition, when network topology have changed, these methods doesn’t adjust their frequency resources of each sector, as a result, the overall throughput will be reduced. There are some researches proposed dynamic FFR and dynamic SFR to solve aforementioned problems.
Although the dynamic adjustment method can enhance the overall throughput, avoiding ICI must be considered. That is, we have to adjust neighbor cell’s frequency at the same time, this will need much of the time to exchange data or massive calculation.
So we propose a simple and fast algorithm to dynamically adjust frequency resources which don’t need to adjust neighbor cell’s frequency at the same time but still can avoid ICI.

摘要 i
Abstract ii
誌謝 iii
圖表目錄 vi
第一章 緒論 8
1.1、 簡介 8
1.2、 研究動機與目的 9
1.3、 章節概要 11
第二章 LTE以及LTE-A概述 12
2.1、 LTE以及 LTE-A系統演進 12
2.1.1 LTE、LTE-A規格簡介 12
2.1.2 中繼站介紹 13
2.1.3 傳輸架構 16
2.1.4 LTE訊框架構 20
2.1.5 下載控制訊息 23
2.1.6 FFR、SFR介紹 24
2.2、 相關研究 27
第三章 頻寬調整機制介紹 31
3.1、 系統基本架構 31
3.2、 系統環境 33
3.3、 研究方法 34
3.3.1 FFR的初始資源分配 35
3.3.2 用戶移動的方法 37
3.3.3 頻寬調整的方法 39
第四章 模擬環境設定與結果 45
4.1.、 模擬環境 45
4.2.、 系統參數 47
4.3.、 效能評估項目與模擬結果分析 49
4.3.1. 平均系統產能 50
4.3.2. 封包丟棄率 63
第五章 結論以及未來研究 74
參考文獻 76

[1] 3GPP TSG RAN WG1：”Evolved Universal Terrestrial Radio Access (E-UTRA), Physical Channels and Modulation (Release 11) ” 3GPP TS 36.211, Dec. 2012
[2] 3GPP TSG RAN WG1：”Evolved Universal Terrestrial Radio Access (E-UTRA), Further advancements for E-UTRA physical layer aspects (Release 9) ” 3GPP TR 36.814, Mar. 2010
[3] Dahlman Erik, Parkvall Stefan and Skold Johan.(2011)”4G LTE/LTE-Advanced for Mobile Broadband”. Academic Pr
[4] "4G LTE Advanced Relay" [Online]. Available: http://www.radio-electronics.com/info/cellulartelecomms/lte-long-term-evolution/4g-lte-advanced-relaying.php
[5] "3GPP LTE - Evolved UTRA - Radio Interface Concepts" [Online]. Available: http://ecee.colorado.edu/~ecen4242/LTE/radio.htm
[6] " LTE:Physical layer Concept (Frame structure, Resource Block and Resource Element 概念) " [Online]. Available: http://xdxdd.blogspot.tw/2012/11/ltephysical-layer-concept-frame.html
[7] " LTE: LTE:Channel Quality Indicator(CQI) feedback " [Online]. Available: http://xdxdd.blogspot.tw/2012/09/lte-ltechannel-quality-indicatorcqi.html
[8] 3GPP TSG RAN WG1：”Evolved Universal Terrestrial Radio Access (E-UTRA), Physical layer procedures (Release 11) ” 3GPP TS 36.213, Feb.2012
[9] M Porjazoski and B Popovski, "Contribution to analysis of Intercell interference coordination in LTE: A fractional frequency reuse case," 2010 Global Mobile Congress (GMC), vol., no., pp.1,4, 18-19 Oct. 2010
 
[10] Du Yang, J. Bastos, C. Verikoukis and J. Rodriguez "Location-aided round robin scheduling for fractional frequency reused LTE-A relay network," 2012 IEEE 17th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD), , vol., no., pp.11,15, 17-19 Sept. 2012
[11] Jianguo Liu, Dongyao Wang, JiYong Pang, Jun Wang Dongyao and Gang Shen, "Inter-cell interference coordination based on soft frequency reuse for relay enhanced cellular network," 2010 IEEE 21st International Symposium on Personal Indoor and Mobile Radio Communications (PIMRC), vol., no., pp.2304,2308, 26-30 Sept. 2010
[12] Yiwei Yu, E Dutkiewicz, Xiaojing Huang, M. Mueck and Gengfa Fang "Performance analysis of soft frequency reuse for inter-cell interference coordination in LTE networks," 2010 International Symposium on Communications and Information Technologies (ISCIT), vol., no., pp.504,509, 26-29 Oct. 2010
[13] D Ogata, A Nagate and T Fujii , "Multi-BS Cooperative Interference Control for LTE Systems," 2012 IEEE 75th Vehicular Technology Conference (VTC Spring), vol., no., pp.1,5, 6-9 May 2012
[14] T Novlan, J.G. Andrews, Sohn Illsoo, R.K. Ganti and A. Ghosh "Comparison of Fractional Frequency Reuse Approaches in the OFDMA Cellular Downlink," 2010 IEEE Global Telecommunications Conference (GLOBECOM 2010), vol., no., pp.1,5, 6-10 Dec. 2010
[15] Manli Qian, Hardjawana W., Yonghui Li, Vucetic B, Jinglin Shi and Xuezhi Yang "Inter-cell interference coordination through adaptive soft frequency reuse in LTE networks," 2012 IEEE Wireless Communications and Networking Conference (WCNC), vol., no., pp.1618,1623, 1-4 April 2012
 
[16] Jun Wang, Jianguo Liu, Dongyao Wang, Jiyong Pang, Gang Shen and Jinhui Chen "Load Balance Based Dynamic Inter-Cell Interference Coordination for Relay Enhanced Cellular Network," 2012 IEEE 75th Vehicular Technology Conference (VTC Spring), vol., no., pp.1,5, 6-9 May 2012