在無線網路研究領域裡，網路模擬軟體一直是研究人員用來觀測及評估其研究概念的重要工具。在經費有限的現實考量下，非商用開放原始碼模擬軟體常成為學術界的首選。由於學術研究具備了創新與超越的本質，所以常面臨現有模組功能不足而需新增或修改的情形。若選用系統架構的先天體質不佳，日後不論是維護、修改或是擴充功能都將變得困難且費時費力。因此，如何選擇一個合適的模擬軟體是一個重要的決定。
　　為了使模擬軟體的系統架構具備擴充彈性及模擬結果具備可信度，本論文提出以設計模式 (Design Patterns) 作為系統架構設計規範的想法，並提出一個網路模擬器架構，稱為 CCG 網路模擬器 (CCG network simulator; CCGns)。CCGns 遵循 IEEE 802.16-2009 標準，使用Java程式語言撰寫，遵從物件導向設計原則，將設計模式運用於系統架構中，是一個以離散事件為基礎的虛擬網路模擬器。由八個套件組成，分別是實體層 (physical layer; PHY)、媒體存取控制層 (media access control layer; MAC)、網路層 (network layer; NET)、事件 (event; EVT)、裝置 (device; DEV)、拓樸 (topology; TPY)、排程 (scheduler; SCH)、和報告 (report; RPT) 套件。主要貢獻包含了六個部分：在實體層套件中提出一個可更換訊框結構的架構、一個結合了實體位址與參考位址定址方法的訊框結構建立方法、以及一個二階段式最小變異數頻寬分配演算法；在媒體存取控制層套件中提出了一個可調整規模的訊息管理與處理架構；在拓樸套件中提出了一個適用於多重跳躍中繼網路架構的建立和操作方法；在排程套件中提出了一個以複數因子為基礎具備同類比較能力的排程單元為基礎的通用排程操作介面架構。
　　本論文不是第一個將設計模式運用於無線網路模擬軟體系統架構的研究，但運用的設計範式數量及種類是最多的，並提供統一塑模語言 (Unified Modeling Language; UML) 圖說明系統架構。在模擬結果方面，特別注重控制訊息處理程序對時間相關的效能評估項目的影響，例如控制訊息的類型、數量和處理程序對輸出資料量、封包延遲時間、封包佇列長度、封包等待時間、以及封包丟棄率的影響，並以數學平均值計算方式驗證模擬結果，以證實此系統架構具備精確的可信度。相信本論文提出的模擬器架構對於需要實作網路模擬軟體的研究人員將會有極大助益。

A network simulator always is an important tool to observe and evaluate the study concept for wireless networks. Considering the restriction of the limited budget, the non-commercial open source simulation software often becomes the top choice of academia. Since the natures of academic study are innovation and excellence, a simulator frequently encounters that the existing modular functions are inadequate and need to be appended or modified. If a selected simulator inherently has poor architecture, the maintenance, recondition, and expansion of functions will become more difficult and more time-consuming in the future, while it is difficult to understand and reuse by the successors. Therefore, how to select a most suitable simulator is an important issue.
In order to make a simulator have flexible architecture and believable results, design patterns are proposed as the norms to design system architecture. To realize this idea, we surveyed six most used simulators, i.e., J-Sim, NS-2, NS-3, OMNet++, OPNET, and QualNet, to ponder their system architectures and design concepts from the source codes and the related literatures of the modular function expansion. We propose a network simulator architecture, named as CCG network simulator (CCGns), which is a discrete-event virtual network simulator and follows the IEEE 802.16-2009 standard. CCGns obeys the object oriented design principles and is coded by the Java language. CCGns comprises eight packages for physical layer (PHY), medium access control layer (MAC), network layer (NET), events (EVT), devices (DEV), topologies (TPY), scheduler (SCH), and reports (RPT), respectively. The main contribution includes six aspects which propose an exchangeable frame structure architecture (AEFSA), a combination of physical address and reference address to build frame structure (CPARABFS), a two-stage minimum variance bandwidth allocation (TSMVBA), a scalable MAC messages management and processing architecture (SM3PA), an applicable for multi-hop relay network architecture (AMRNA), and a comparable compound factors-based common scheduler operating interface architecture (C2FCSOIA).
To the best of our knowledge, this article is not the first one to apply the design patterns for the simulator architectures of wireless network, but we use more design patterns and types than the others and also provide the unified modeling language (UML) figures to explain the system architectures. We particularly focus on how the management procedure of control messages influences the time-related performance evaluation metrics, e.g., how the amount and processing time of different control messages affect data output rate, packet delay, packet queue length, packet waiting time and packet drop ratio. By using mathematic calculation to verify the simulation results, the proposed system architecture has been proven to possess excellent fidelity. We hope this study will benefit researchers who need to implement their network simulators.

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