在NCTUns平台上模擬IEEE 802.16j Transparent mode WiMAX網路

Abstract

全球互通微波存取技術 (Worldwide Interoperability of Microwave Access , 簡稱WiMAX)為近年來新興的無線寬頻存取技術，其目的為增加傳統固接網路中用戶端 (last-mile)網路接取不足的頻寬。IEEE 802.16j (Mobile Multi-hop Relay WiMAX, 簡稱 MMR WiMAX)為目前正在制訂的WiMAX新的標準草案，此標準草案是以移動式IEEE 802.16e為基礎所延伸的標準，提供在WIMAX網路下資料多段轉傳 (multi-hop relay)的能力與增進基地台涵蓋率 (coverage)，並且藉由中繼台 (Relay Station)的佈建降低建置基地台所需的昂貴成本與提高WiMAX系統傳輸效能。 在本篇論文中，我們在NCTUns網路模擬器裡開發IEEE 802.16j 中控型排程機制的穿透式網路模組。我們所開發的模擬模組在此種網路拓樸下提供三種新的節點，分別是MR-BS (Multi-hop Relay Base Station)、FRS (Fixed Relay Station)和MS (Mobile Station)，供使用者方便建置網路拓樸。在媒體存取控制層，我們的模組支援簡單的用戶端路徑選擇演算法和動態調整設備台間使用的調變方式；而實體層的部份，則是採用OFDMA TDD模式並且搭配穿透式網路訊框架構來設計。根據我們的模組實作，可以提供對IEEE 802.16j穿透式網路研究有興趣的使用者一個方便的模擬平台。

WiMAX is a new broadband wireless access technology, which is designed to provide a last-mile solution for metropolitan area networks. The IEEE 802.16j (MMR WiMAX) draft standard is currently under development and based on the IEEE 802.16e (Mobile WiMAX) standard. It not only provides multi-hop relay capability but also extends base station coverage by deploying relay stations around base stations. In addition, by deploying cost-effective relay stations, the IEEE 802.16j can reduce the number of base stations that should be deployed in the network, which greatly reduces the deployment cost of a network.

In this thesis, we developed the IEEE 802.16j centralized scheduling transparent WiMAX network protocol modules on the NCTUns network simulator. We implemented three new types of nodes, MR-BS (Multi-hop Relay Base Station), FRS (Fixed Relay Station) and MS (Mobile Station). The developed MAC-layer modules support a simple subscriber path selection algorithm and an adaptive modulation scheme to boost network performance. At the physical layer, we use the OFDMA TDD mode collocating frame structure in transparent-mode WiMAX network. Our work provides a convenient simulation platform for researchers that are interested in IEEE 802.16j transparent mode WiMAX networks.