Long Term Evolution LTE Air Interface Core Network

課程目標 • 讓 學 生 了 解 Long Term Evolution (LTE)的 Air Interface與 Core Network之演進 • Evolved Universal Terrestrial Radio Access Network Access Network (E-UTRAN)與 System Architecture Evolution (SAE)的網路架構 • LTE/SAE網路協定之RRC Connection Procedures之簡介 • Evolved Packet Core元件的相關知識 4 L A B

LTE之演進與簡介 • Long Term Evolution (LTE) 指3 GPP (The 3 rd Generation Partnership Project ) Release 8 以後的版本，主要為R 8、R 9 版本，亦被稱為 3. 9 G • 雖然 3 GPP R 8/R 9常被電信營運商誇稱為 4 G LTE，但嚴格 來說，直到 3 GPP R 10才真正符合國際電信聯 (International Telecommunication Union；ITU)的4 G標準 6 L A B

3 GPP與LTE之演進 (Study on All IP Network) (MTC) Rel. 7 3 GPP Rel. 8 3 GPP Rel. 9 (LTE; 3. 9 G) 2009 2010 3 GPP Rel. 11 3 GPP Rel. 10 2013 2012 8 Rel. 13 (B 4 G) (LTE-A; 4 G) 2011 Rel. 12 2014 2015 2016 L A B

LTE之主要技術 • All IP之扁平化網路架構 • 主要技術架構 – 下載為正交分頻多重存取(OFDMA；Orthogonal Frequency Division Multiple Access) – 上載為單載波分頻多重存取(SC-FDMA；Single-Carrier Frequency-Division Multiple Access) – 多輸入多輸出(MIMO；Multiple Input Multiple Output) – 利用上述技術提高頻譜利用效率及無線網路容量 9 L A B

LTE/SAE網路架構－演進 • 相對於 3 GPP Universal Mobile Telecommunications System (UMTS，為最廣泛應用之3 G技術)，LTE包含以下的演進 – Radio Access • Evolved Universal Terrestrial Radio Access Network (E -UTRAN) – Non-Radio Aspect • System Architecture Evolution (SAE) • 以High Level的角度觀之，LTE網路包含 – 核心網路Evolved Packet Core (EPC) in SAE – 接取網路E-UTRAN 11 L A B

LTE/SAE網路架構－演進(Cont. ) UMTS 3 G UTRAN Gateway GPRS Support Node GGSN Serving GPRS Support Node SGSN RNC Node. B LTE EPC in SAE S 1 RNC Node. B Radio Network Controller e. Node. B X 2 e. Node. B E-UTRAN 12 L A B

LTE/SAE之架構 3 GPP Access EPC in SAE E-UTRAN e. Node. B HSS MME PCRF UE S-GW Wi. Fi AP ANDSF P-GW e. PDG Abbreviation List UE: User Equipment MME: Mobility Management Entity S-GW: Serving Gateway P-GW: Packet Data Network Gateway e. PDG: Evolved Packet Data Gateway HSS: Home Subscriber Server AP: Access Point PCRF: Policy and Charging Rules Function ANDSF: Access network discovery and selection function Internet Non-3 GPP Access 13 L A B

LTE/SAE之訊息傳輸 • 區分為Control Plane與User Plane以便管理 • Control Plane UE e. NB MME • User Plane UE e. NB S-GW 14 P-GW L A B

Evolved Universal Terrestrial Radio Access Network • E-UTRAN為LTE無線部份之架構 • E-UTRAN包含UE (User Equipment)及Evolved Node. B (簡稱 e. Node. B或e. NB) • UE與e. NB透過LTE-Uu無線通訊界面互相通訊，LTE-Uu可 分為三層 15 L A B

LTE-Uu－Layer 3 • Layer 3 – Non-Access Stratum (NAS) • 移動管理 • Bearers設定 • 用戶認證 – Radio Resource Control (RRC) • 無線資源管理 • RRC之下各層的設定 16 L A B

LTE-Uu－Layer 2 • Layer 2 – Packet Data Convergence Protocol (PDCP ) • 處理標頭壓縮 • 加密運算 – Radio Link Control (RLC) • ARQ與HARQ等重傳 • 封包分割與重組 – Medium Access Control (MAC) • Qo. S (Quality of Service) 排程 17 L A B

LTE-Uu－Layer 1 • Layer 1 – Physical (PHY) • 將資料轉為實體訊號發送 • 包含OFDMA與MIMO技術 18 L A B

LTE-Uu之協定架構－ User Plane Protocol Stack Layer 3 Layer 2 Layer 1 UE e. NB RRC PDCP RLC MAC PHY 19 L A B

LTE-Uu之協定架構－ Control Plane Protocol Stack UE Layer 3 Layer 2 Layer 1 e. NB NAS MME NAS RRC PDCP RLC MAC PHY 20 L A B

RRC Connection Procedures • RRC的狀態分為 RRC_IDLE 與 RRC_CONNECTED • IDLE狀態下UE不會被分配到無線資源 • 需要傳輸資料時， UE 轉入 RRC_CONNECTED程序以 取 得無線資源 • 以下介紹四種RRC控制程序 – RRC Connection Establishment – RRC Initial Security Activation – RRC Connection Reconfiguration – RRC Connection Release 22 L A B

RRC Connection Procedures－ RRC Connection Establishment UE E-UTRAN RRCConnection. Request RRCConnection. Setup. Complete RRC連線成功 RRC 狀態： RRC_IDLE 變成 RRC_CONNECTED L A B

RRC Connection Procedures－ RRC Connection Establishment (Cont. ) UE E-UTRAN RRCConnection. Request RRCConnection. Reject RRC連線失敗 RRC 狀態維持在RRC_IDLE 24 L A B

RRC Connection Procedures－ RRC Initial Security Activation UE E-UTRAN Security. Mode. Command Security. Mode. Complete 完成UE與e. NB之驗證 後可做保密性及資料完整性等安全防護 25 L A B

RRC Connection Procedures－ RRC Connection Reconfiguration UE E-UTRAN RRCConnection. Reconfiguration. Complete 可設定Handover等各種無線相關控制 26 L A B

RRC Connection Procedures－ RRC Connection Release UE E-UTRAN RRCConnection. Release RRC 狀態： RRC_CONNECTED變成RRC_IDLE 27 L A B

LTE/SAE元件－ System Architecture Evolution • 基於GPRS核心網路(General Packet Radio Service Core Network)的演進 • 演進理念 – 加強 Packet Switched Technology 以處理快速成長的 IP Traffic • Higher Data Rates • Lower Latency • Packet Optimized System – 更高Throughput • Fully IP Based Network • Simplified Network Architecture • Distributed Control 29 L A B

LTE/SAE元件－ Evolved Packet Core • SAE的主要組成部份為EPC (Evolved Packet Core ) • EPC又被稱為SAE核心 (SAE Core) • EPC之作用與GPRS網路相似 – 通過Mobility Management Entity (MME)、Serving Gateway (S-GW)和Packet Data Network Gateway (PDNGW或P-GW)等子元件實現 31 L A B

LTE/SAE元件－ Evolved Packet Core (Cont. ) • Main Logical Nodes – Mobility Management Entity (MME) – Serving Gateway (S-GW) – Packet Data Network Gateway (PDN Gateway或P-GW) • Other Nodes and Functions – Home Subscriber Server (HSS) – Access Network Discovery and Selection Function (ANDSF) – Evolved Packet Data Gateway (e. PDG) – Policy and Charging Rules Function (PCRF) 32 L A B

LTE/SAE元件－ Home Subscriber Server (HSS) • • 包含與用戶相關信息和訂閱相關信息的中央資料庫 支援呼叫和會話建立(Call and Session Establishment) 用戶認證和訪問授權 HSS 植基於 pre-Rel-4 Home Location Register (pre-Rel. HLR) and Authentication Center (Au. C) 36 L A B

LTE/SAE元件－ Evolved Packet Data Gateway (e. PDG) • 確保數據傳輸的UE通過不可信的非 3 GPP接入網連接到 EPC • e. PDG與UE之間會建立一個Internet Protocol Security (IPSec) 隧道 38 L A B

EPC Protocol Stack－MME Protocols • MME Protocols包含 – S 1 -MME stack • 支援與e. NB之間的S 1 -MME Interface • The integrated S 1 MME interface stack consists of Internet Protocol (IP), Stream Control Transmission Protocol (SCTP), S 1 Application Part (S 1 AP) – S 11 stack • 支援與S-GW之間的S 11 Interface • The integrated S 11 interface stack consists of IP, User Datagram Protocol (UDP) and Evolved GPRS Tunneling Protocol-Control (e. GTP-C) 40 L A B

EPC Protocol Stack －S-GW Protocols • S-GW Protocols包含 – 支援與MME之間S 11 Interface 的S 11 control plane stack – 支援與P-GW之間S 5/S 8 Interface的S 5/S 8 Control Plane Stack – 支援與P-GW之間S 5/S 8 Interface的S 5/S 8 Data Plane Stack – 支援與e. NB之間S 1 User Plane Interface的S 1 Data Plane Stack – 支援與Serving GPRS support node (SGSN)之間S 4 User Plane Interface的S 4 Data Plane Stack 41 L A B

EPC Protocol Stack －P-GW Protocols • 包含 – S 5/S 8 Control Plane Stack • 支援與S-GW之間S 5/S 8 Interface • The integrated control plane stack for the S 5/S 8 interfaces consists of IP, UDP and Evolved GPRS Tunneling Protocol-Control (e. GTP-C) – S 5/S 8 Date Plane Stack • 支援與S-GW之間S 5/S 8 interface • The integrated data plane stack for the S 5/S 8 interface consists of IP, UDP and Evolved GPRS Tunneling Protocol-User Data Tunneling (e. GTP-U) 42 L A B

台灣的LTE電信營運廠商與其得標頻段 (1/2) 得標者 中華電信 台灣大哥大 得標頻段 B 2 (上下行各10 MHz) C 5(上下行各15 MHz) 上行895~905 MHz 上行1725~1735 MHz 上行1755~1770 MHz 下行940~950 MHz 下行1820~1830 MHz 下行1850~1865 MHz A 4 (上下行各15 MHz) C 1 (上下行各15 MHz) 上行733~748 MHz 上行1710~1725 MHz 下行788~803 MHz 下行1805~1820 MHz B 1 (上下行各10 MHz) 台灣之星 上行885~895 MHz 下行930~940 MHz 46 L A B

台灣的LTE電信營運廠商與其得標頻段 (2/2) 得標者 得標頻段 A 1 (上下行各10 MHz) 亞太電信 上行703~713 MHz 下行758~768 MHz A 3 (上下行各10 MHz) 國基電子 上行723~733 MHz 上行905~915 MHz 下行778~788 MHz 下行950~960 MHz A 2 (上下行各10 MHz) 遠傳電信 B 3 (上下行各10 MHz) C 4 (上下行各10 MHz) 上行713~723 MHz 上行1735~1745 MHz 上行1745~1755 MHz 下行768~778 MHz 下行1830~1840 MHz 下行1840~1850 MHz 47 L A B

參考資料 • 3 GPP TS 23. 002: Network architecture http: //www. 3 gpp. org/dynareport/23002. htm • 3 GPP TS 36. 300: Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN) http: //www. 3 gpp. org/dynareport/36300. htm • 3 GPP TS 36. 331: Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification http: //www. 3 gpp. org/dynareport/36331. htm 48 L A B

參考資料(Cont. ) • Wikipedia: LTE https: //en. wikipedia. org/wiki/LTE_(telecommunication) • Wikipedia: SAE https: //en. wikipedia. org/wiki/System_Architecture_Evolution • 國家通訊傳播委員會 NCC http: //www. ncc. gov. tw/chinese/index. aspx • 郭昱賢、林盈達「LTE 架構、協定與效能」，2011。 Document Available at http: //speed. cis. nctu. edu. tw/~ydlin/miscpub/YHGuo-LTE. pdf 49 L A B