Gigabit等級分碼多工式乙太被動式光纖網路平台於場式可程式化閘陣列上之實作

CDMA Gigabit-Ethernet Passive Optical Network Design and Implementation in FPGA

廖彥鈞(Yen-Chun Liao)

指導教授 ： 吳靜雄

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.00564

摘要

隨著網際網路的快速發展，用戶對頻寬的需求量也大幅增加。研究顯示，自1990年開始網路上資料的傳輸量正以超過百分之百的速度在快速增加(在1995及1996年增加量甚至超過1000%)。骨幹網路在頻寬使用率上，由於光通訊原件科技的大幅進步以及DWDM應用逐漸成熟的影響下，一直都是處於非飽和的狀態上，但是現今頻寬供給的量似乎並沒有跟著頻寬需求一起大幅成長，最主要的瓶頸還是出在最後一哩(last mile)的接取網路上。為了要解決頻寬不足的瓶頸，在最後一哩必須引進光纖設備，考量到乙太網路在區域網路的廣泛佔有率以及容易擴充與管理的特性，被動式乙太光纖網路結合了低成本的乙太網路設備與低成本的光纖網路架構，應該是下一代存取網路的最佳方案之一。

在本篇論文中，我們設計並實作了一個全新同步演算法的被動式乙太光纖網路。在我們提出的系統裡上行端採用同步光分碼多工存取方式而非常見之分時多工存取來避免碰撞。我們採用完美相差碼來作為同步分碼多工之展頻碼。我們實作上架設了包含一個光線路終端(Optical Line Terminal)與兩個光網路單元(Optical Network Unit)的被動式乙太光纖網路雛形系統。同時我們也驗證了所提出的同步方式並且可以達到125微微秒以內的誤差。我們利用場式可程式化閘陣列(FPGA)來實作光線路終端與光網路單元之電路。在本文中，我們詳細描述所有系統模組的設計流程與操作原理並包含整體系統的完整模擬。最後成功的完成20公里上傳十億兩千五百萬位元下傳壹百億位元乙太被動式光網路。

關鍵字

被動式乙太光纖網路 ； 光分碼多工 ； 完美相差碼 ； 光線路終端 ； 光網路單元

並列摘要

In recent years the bandwidth of backbone network has experienced substantial growth, but little has changed in the access networks. To solve bandwidth bottlenecks of access network, optical fibers are necessary in the last mile. Considering that Ethernet, which is low cost and easy to installation and management, has conquered the ground in local area networks (LANs), Ethernet passive optical network (EPON) may be the best solution for the broadband access. EPON combines the low cost Ethernet equipment and low cost fiber infrastructure, which is the promising candidate of next generation of last mile.

In this thesis, we design and implement an EPON with a new upstream scheme for fiber-optic code division multiple access (CDMA) systems. In the proposed system, we adopt Synchronous Optical CDMA scheme in the upstream traffic rather than the conventional scheme of time division multiple access (TDMA). Perfect difference codes are adopted as our synchronous spreading codes. An EPON system which includes one optical line terminal (OLT) and two optical network units (ONUs) is experimentally implemented. System synchronization is realized and the synchronization error less than 125ps is achieved. The OLT/ONU circuits are implemented by a Field-Programmed-Gate-Array. We describe the design flow and operation principle of each module, and complete the whole simulation of the system. Finally, we demonstrate a 20 km EPON system with downlink 10Gbps and uplink 1.25Gcps transmission rates successfully.

並列關鍵字

EPON ； OCDMA ； PDC ； OLT ； ONU

參考文獻

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[5] Po-Chiun Huang, “Design and Implementation of an Ethernet Passive Optical Network Using Perfect Difference Codes,” M.S. Thesis 2003, Graduate Institute of Communication Engineering, National Taiwan University.

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