在5G (the 5th Generation)行動通訊網路中，使用者設備(User Equipment, UE)要上傳資料到雲端伺服器(Internet Server)時，它必須先傳送控制封包(Control Packet, CP)到5G Core (5GC)進行註冊與認證，接著它才能上傳使用者封包(User Packet, UP)的資料到雲端伺服器。在UE與5GC的運作中，不管是CP或UP都要先傳到5GC，如此運作方式會沒有必要的增加UP終點端到終點端的延遲(End-to-End Delay, ETED)，為了解決這個問題，本論文提出一個使用多存取邊緣運算(Multi-access Edge Computing, MEC)的隧道(Tunnel)技術來完成控制封包與使用者封包的分流(Substream Separation of Control and User Packets, SSCU)，SSCU的運作機制可以分成三個部分，第一個部分是當一個CP或UP在UE產生時，SSCU會在UDP (Usrer Datagram Protocol)上新增一個封包轉傳控制協定(Packet Forwarding Control Protocol, PFCP)的標頭(Header)，我們使用PFCP標頭的訊息類型(Message Type, MT)欄位來區分CP與UP。第二個部分是SSCU在MEC建立一個隧道(Tunnel)，也就是在CP或UP原本的IP Header上另外增加一個新的IP Header。第三個部分是SSCU使用PFCP標頭的MT欄位在5GC解除隧道並接收CP。為了驗證我們所提出的SSCU在5G行動通訊網路上的效能改進，我們使用TCP/UDP Sockets來撰寫C語言的模擬程式，在不同背景資料流的影響下，我們分析比較CP與UP的 ETED、在路由器中CP與UP的封包遺失率、在Internet Server的UP接收位元率。

In 5G mobile communication networks, when a user equipment (UE) wants to uplaod its data to an Internet server, it will first transmit control packets (CP) to 5G Core (5GC) for the registration and authentication. After that, it may be able to transmit its data via user packets (UP) to the server. In the original UE and 5GC operations, both CP and UP must be sent to 5GC first, which unnecessarily increases the end-to-end delay (ETED) of UP. To solve this problem, in this thesis, we propose a tunnel-based solution leveraging Multi-access Edge Computing (MEC) for Substream Separation between Control and User Packets (SSCU). The mechanism of SSCU is divided into three parts. In the first part, when a CP or UP is generated, SSCU must add a Packet Forwarding Control Protocol (PFCP) header on the top of UDP (User Datagram Protocol). We use the Message Type (MT) field in the PFCP header to distinguish between CP and UP. In the second part, a tunnel is established at MEC, adding a new IP header to the original IP header of CP or UP. In the third part, SSCU utilizes the MT field in the PFCP header to release the tunnel and receive CP. To demonstrate the effectiveness of the proposed SSCU in 5G mobile communication networks, we use TCP/UDP sockets to perform simulation written in C. From the simulation results, we analyze and compare ETED between CP and UP, with and without the influence of background traffic. Additionally, we compare packet loss rates of CP and UP in a router, and UP receiving bit rate at an Internet server.

論文審定書 i
致謝 ii
摘要 iii
Abstract iv
目錄 v
圖目錄 viii
表目錄 x
第一章 導論 1
1.1 研究動機 1
1.2 研究方法 1
1.3 章節介紹 2
第二章 5G RAN與MEC 3
2.1 MEC 3
2.2 5G RAN 5
2.2.1 5GC 5
2.3 PFCP 8
2.4 隧道協定 10
2.4.1 GTP Header 11
2.4.2 GTP Tunnel 11
2.4 相關研究 12
第三章 控制與使用者封包的分流 16
3.1 5G RAN與MEC 16
3.1.1 傳統的5G RAN 17
3.1.2 SSCU的封包分流 17
3.2 SSCU的封包分流 18
3.2.1 SSCU的UE封包產生 18
3.2.2 SSCU的MEC Tunnel 19
3.2.3 SSCU在5GC的封包接收 21
3.2.4 SSCU在Internet Server的封包回傳 21
3.3 SSCU分流的運作流程 22
3.3.1 UE傳送封包的機制 22
3.3.2 MEC攔截並轉傳封包的流程 23
3.3.3 5GC接收封包的流程 24
3.3.4 Internet Server回傳封包的流程 25
第四章 模擬結果與分析 27
4.1 模擬拓樸 27
4.2模擬程式的虛擬碼 28
4.2.1 UE的虛擬碼 28
4.2.2 MEC Tunnel的虛擬碼 33
4.2.3 5GC的虛擬碼 35
4.2.4 Internet Server做封包回傳 37
4.2.5 路由器轉傳封包的虛擬碼 39
4.3 模擬結果與分析 44
4.3.1封包延遲時間 45
4.3.2 在路由器的封包遺失率 50
4.3.3 在Internet Server的UP接收位元率 51
4.3.4 整體封包的ETED 52
第五章 結論與未來工作 54
5.1 結論 54
5.2 模擬程式所遭遇的困難 54
5.3 未來工作 55
參考文獻 56
Acronyms 60
Index 62

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