臺灣博碩士論文加值系統

近年來行動網路的興起及智慧型行動裝置的普及，造成有越來越多行動裝置具有連網功能，隨時隨地上網成為習慣；使用者對網路的需求越來越高，但不希望有延遲或無法傳輸資料的情況發生，因此，如何降低干擾或提升使用者的服務品質是一個重要的議題，隨著IEEE 802.11標準中802.11n及802.11ac通訊協定使用2.4GHz與5GHz雙頻基地台的出現，讓此議題有更新的進展。在本篇論文中，我們希望藉由佈建不同種類的基地台(單頻、雙頻或三頻)和配置不同的通訊協定(802.11 g/n/ac)及頻道，達到降低頻道間的干擾和維持使用者的服務品質，也就是讓使用者的延遲能盡量降低。主要希望可以運用於機場基地台之佈建，因為機場是人流最多最密集的區域，各種網路需求都會產生，且不同商家和機場本身就有不同的基地台配置，每個人所使用的手機型號和應用也不同，因此會是干擾最常發生也最需要解決的場合。
我們將上述的配置問題轉化成一數學規劃問題，目標式為最小化使用者的延遲，並提出一個以拉格蘭日鬆弛法為基礎的解題方法，透過鬆弛某些限制式，讓我們可以更快速的獲得可行解，再轉化為原問題的可行解，以求得最佳化的參數運用於配置規劃，其結果可以給機場的管理者和網路服務營運商作為佈建基地台的參考。

With the traffic demands are increased in 802.11 wireless networks, more and more mobile devices have applications connected to the Internet. Under this trend, the delay situations and unstable transmission environments are not satisfied on data rate requirements. Therefore, how to reduce the interference and improve the user''s Quality of Service (QoS) is an important issue. With the appearance of protocol using 5GHz band and appearance of dual-band and tri-band APs, let this issue having new development. In this thesis, we consider through the placement of the APs and choose different types of AP, each of which have to select corresponding protocol, and channel assignment to reduce co-channel interference and maintain user’s QoS, namely enable user’s delay can lower as far as possible. We mainly hope the AP assignment algorithm can be used in airport. Because airport is the most populous places, many demand of internet will happened. Stores in airport and airport itself will have different AP configuration, this may cause more interference. Therefore, airport will be most interference place and must be solved.
We apply mathematical model to describe the above assignment problem. Objective function will be minimum user’s delay. A Lagrangean Relaxation (LR) based method will be proposed to solve the problem. Through relaxing some constraints, enable us to obtain solution more quickly. Than transform the solution to solution of primal problem, getting the optimal parameters for the configuration planning. The result can be a reference of AP assignment for manger of airport and Internet Service Providers (ISP).

謝誌..........I
論文摘要..........III
Thesis Abstract..........V
Table of Contents..........VII
List of Figures..........IX
List of Tables..........XI
Chapter 1 Introduction..........1
1.1 Background..........1
1.2 Motivation..........4
1.3 Literature Survey..........6
1.3.1 IEEE 802.11 Protocols..........6
1.3.2 Types of Access Point..........8
1.3.3 Interference & SINR..........9
1.3.4 AP Assignment & Channel Assignment..........10
1.3.5 Network Delay..........11
1.4 Thesis Organization..........13
Chapter 2 Problem Formulation..........15
2.1 Problem Description..........15
2.1.1 Network Model..........15
2.1.2 Propagation Model..........16
2.1.3 Capture Interference Model..........18
2.1.4 Wi-Fi Channel Model..........18
2.1.5 AP Combination Model..........19
2.1.6 Coverage Model..........19
2.2 Mathematical Formulation..........21
Chapter 3 Solution Approach..........29
3.1 Introduction to the Lagrangean Relaxation..........29
3.2 Solution Approach..........31
3.2.1 Lagrangean Relaxation Problem..........31
3.2.2 The Dual Problem..........44
3.2.3 Initial Primal Feasible Solution..........46
3.2.4 Get Primal Feasible Solution..........49
Chapter 4 Experience Results..........53
4.1 Simple Algorithms..........53
4.2 Experiment Environments..........54
4.3 Scenarios Design..........57
4.4 Experimental Results..........59
4.5 Results Discussion..........62
Chapter 5 Conclusions and Future Work..........63
5.1 Conclusions..........63
5.2 Future Work..........64
Reference..........65

[1]Y. Li, X. Wang, and S.A. Mujtaba, “Cochannel Interference Avoidance Algorithm in 802.11 Wireless LANs,” Proc. of the 2003 IEEE 58th Vehicular Technology Conference(VTC 2003), Oct. 2003, Vol. 4, pp. 2610 – 2614.
[2]A. Iyer, C. Rosenberg, and A. Karnik, “What is the Right Model for Wireless Channel Interference?,” IEEE Trans. on Wireless Communications, May 2009, Vol. 8, No. 5, pp. 2662 – 2671.
[3]H.S. Kim, E. Kim, and H. Kim, “QoE-driven Wi-Fi Selection Mechanism for Next Generation Smartphones,” Proc. of the 2012 First IEEE Workshop on Enabling Technologies for Smartphone and Internet of Things (ETSIoT 2012), Jun. 2012, pp. 13 – 18.
[4]Y. Shi, Y. Thomas Hou, J. Liu, and S. Kompella, “How to Correctly Use the Protocol Interference Model for Multi-hop Wireless Networks,” Proc. of the tenth ACM international symposium on Mobile ad hoc networking and computing (MobiHoc 2009), May 2009, pp. 239 – 248.
[5]S. Chieochan, E. Hossain, and J. Diamond, “Channel Assignment Schemes for Infrastructure-based 802.11 WLANs: A Survey,” IEEE Trans. on Communications Surveys & Tutorials, Feb. 2010, Vol. 12, No. 1, pp. 124 – 136.
[6]M. Elwekeil, M. Alghoniemy, H. Furukawa, and O. Muta, “Lagrangian Relaxation Approach for Low Complexity Channel Assignment in Multi-cell Wlans,” Proc. of the 2013 International Conference on Computing, Networking and Communications (ICNC 2013), Jan. 2013, pp. 138 – 142.
[7]A. Eisenblatter, H.F. Geerdes, and I. Siomina. “Integrated Access Point Placement and Channel Assignment for Wireless LANs in an Indoor Office Environment,” Proc. of the IEEE International Symposium on World of Wireless, Mobile and Multimedia Networks(WoWMoM 2007), Jun. 2007, pp. 1 – 10.
[8]P. Chatzimisios, V. Vitsas, and A.C. Boucouvalas. “Throughput and Delay Analysis of IEEE 802.11 Protocol,” Proc. of the 2002 IEEE 5th International Workshop on Networked Appliances, Oct. 2002, pp. 168 – 174.
[9]P. Raptis, V. Vitsas, K. Paparrizos, P. Chatzimisios, A.C. Boucouvalas, and P. Adamidis, “Packet Delay Modeling of IEEE 802.11 Wireless LANs,” Proc. of the 2nd International Conference on Cybernetics and Information Technologies, Systems and Applications (CITSA 2005), Jul. 2005, Vol. 7176.
[10]P. Raptis, V. Vitsas, K. Paparrizos, P. Chatzimisios, and A.C. Boucouvalas, “Packet Delay Distribution of the IEEE 802.11 Distributed Coordination Function,” Proc. of the 6th IEEE International Symposium on World of Wireless Mobile and Multimedia Networks(WoWMoM 2005), Jun. 2005, pp. 299 – 304.
[11]P. Chatzimisios, A.C. Boucouvalas, and V. Vitsas, “IEEE 802.11 packet delay-a finite retry limit analysis,” Proc. of the 2003 IEEE Global Telecommunications Conference(GLOBECOM 2003), Dec. 2003, Vol. 2, pp. 950 – 954.
[12]M.A.R. Siddique and J. Kamruzzaman, “VoIP Capacity over PCF with Imperfect Channel,” Proc. of the 2009 IEEE Global Telecommunications Conference(GLOBECOM 2009), Dec. 2009, pp. 1 – 6.
[13]B. Sikdar, “An Analytic Model for the Delay in IEEE 802.11 PCF MAC-Based Wireless Networks,” IEEE Trans. on Wireless Communications, Apr. 2007, Vol. 6, No. 4, pp. 1542-1550.
[14]S. Sendra, J. Lloret, C. Turro, and J.M. Aguiar, “IEEE 802.11a/b/g/n short–scale indoor wireless sensor placement,” International Journal of Ad Hoc and Ubiquitous Computing, Oct. 2014, Vol. 15, No. 1-3, pp. 68-82.
[15]M. Lott and I. Forkel, “A multi-wall-and-floor model for indoor radio propagation,” Proc. of the 2001 IEEE 53rd Vehicular Technology Conference(VTC 2001), May 2001, Vol. 1, pp. 464 – 468.16.
[16]AP55Specsheet Retrieved June 10, 2016, from www.cyberoam.com/downloads/Sophos/Specsheet/AP55Specsheet.pdf
[17]MCS : Index Retrieved June 10, 2016, from mcsindex.com