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  • 學位論文

802.16網狀基地台換手機制之研究

A Study of Handover on 802.16 Wireless Networks with Mesh Base Stations

指導教授 : 張進福

摘要


WiMAX系統(也稱做802.16)為新一代的無線寬頻接取網路,規格中將現今最新潮先進的行動通訊技術訂立其中,而在其所訂立的行動版本中,新增了使用裝置的行動支援,讓行動多媒體應用具有更多的可能性,本研究也本著此規格所著重的行動性,而將重點放在研究行動通訊系統中的換手技術,換手技術是行動式通訊系統很重要的一個環節,若是無法處理得當的話,往往使用者便會感到不耐,在本文中我們會對802.16e所訂立的換手程序做一個詳細的介紹,並且仔細分析其中各個步驟對於換手延遲時所造成的影響,除此之外,本研究假設了一個環境,此環境的基地台大部分為網狀模式的網狀基地台,其中大部分基地台並無法直接取得網際網路上的資訊,而必須經由路由的程序才可以與此區域中的系統基地台連線進而取得網際網路上的資訊,此特殊環境的設定是考量到在城市或是在深山偏遠地區,若要布建網路需要花費大量的成本,而且有些地方重新布建實體網路實屬不易,所以我們才會設定此網狀基地台環境,本研究將802.16e中的各項換手機制套用在此環境上,並且發現網狀基地台環境中路由延遲對於各個換手機制均造成很大的效能衰退,所以我們提出了一個簡單的機制,改善這之中某些換手機制在網狀基地台環境下的換手失敗率效能,並在最後一章對於觀察到的現象作結論與心得建議。

並列摘要


Mobile WiMAX followed the 802.16e standards provides broadband services with high mobility capability under wireless environment. Handover is an essential function for every mobile communication systems and users suffer handover failure due to handover process and channel resource. WiMAX operates under two modes : PMP (Point to Multi-point) mode and Mesh mode. Mesh mode provide the networks with larger data coverage, subscriber stations and Base stations in mesh mode have self-configured and self-organized capabilities. Mesh mode in WiMAX reduce the cost of constructing a network in metropolitan area or in rural area due to its radio access characteristic for Base stations. In this thesis, we only focus on the environment with mesh base stations, the mobile subscriber stations use PMP mode to access services. In this way, the handover procedures are extended to execute routing process to the base stations which connect to Internet after the regular handover procedures finished. Therefore the handover time will be longer to increase the failure rate. Different handover mechanism (hard handover and soft handover) are discussed in this thesis, we founded that routing delay due to mesh base stations environment dominates the handover failure rate in some handover types. There is a comparison of handover performance in standard environment and in mesh base stations environment. To reduce the effect of routing delay, this thesis propose a simple method to make the neighbor base stations do the routing procedure in advance, and the simulation result show it works.

並列關鍵字

802.16 802.16e WiMAX Mesh Base station Handover

參考文獻


[21]李松晃,簡述無線通訊技術,國家系統晶片設計中心,國研科技 第五期 2005 一月出版,Page 40-44
[5]陳子宏,IEEE 802.16 Mesh networks 排程控制訊息成本之效能分析,碩士論文 國立暨南國際大學資訊工程學系(研究所),June 2007.
[9] 陳緯航,802.16 換手機制之實現與效能評估 Implementation, Evaluation , and Comparison of 802.16 MAC Layer Handover Mechanisms,碩士論文,國立台灣大學電機資訊學院電信工程學研究所,2007年七月。
[3] Jeffrey G. Andrews, Arunabha Ghosh , and Rias Muhamed. Fundamentals of WiMAX: Understanding Broadband Wireless Networking.
[4] Ian F. Akyildiz, Xudong Wang, Weilin Wang, Wireless mesh networks: a survey,Computer Networks 47 (2005) 445–487

被引用紀錄


陳柏任(2009)。WiMAX與LTE間異質無線網路共構研究與效能提升〔碩士論文,國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342%2fNTU.2009.02604
潘欣侑(2012)。WiMAX 微基站服務換手加速機制之研究〔碩士論文,大同大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0081-3001201315112405

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