第四代行動通訊系統 (4G)－－ Long Term Evolution Advanced (LTE Advanced) 陳昱仁 長庚大學資訊管理學系

第四代行動通訊系統 (Fourth Generation, 4G) 2008年3月，在國際電信聯盟-無線電通訊部門（ITU-R）指定一組用於4G標準的要求，命名為 IMT-Advanced 規範，設定4G服務的峰值速度要求在高速移動的通訊（如在火車和汽車上使用）達到100 Mbit/s，固定或低速移動的通訊（如行人和定點上網的用戶）達到1 Gbit/s 第一發布版本的LTE（3GPP Release 8）和WiMAX（IEEE 802.16e）支援遠小於1 Gbit/s的峰值位元率，它們不是完全IMT-Advanced的標準，但往往許多電信服務提供商宣傳其為4G網路 2009年9月，各項技術提案被提交給國際電信聯盟（ITU）為4G候選者，基本上所有的建議都是基於下列兩種技術： LTE-Advanced（3GPP Release 10）：由3GPP標準化 WirelessMAN-Advanced（IEEE 802.16m）：由IEEE標準化

IMT-Advanced International Mobile Telecommunications-Advanced (IMT-Advanced) systems are mobile systems that include the new capabilities of IMT that go beyond those of IMT-2000 Such systems provide access to a wide range of telecommunication services including advanced mobile services, supported by mobile and fixed networks, which are increasingly packet-based IMT-Advanced systems support low to high mobility applications and a wide range of data rates in accordance with user and service demands in multiple user environments IMT-Advanced also has capabilities for high quality multimedia applications within a wide range of services and platforms, providing a significant improvement in performance and quality of service

The “VAN diagram”

Requirements of IMT-Advanced Based on an all-Internet Protocol (IP) packet switched network Interoperability with existing wireless standards A nominal data rate of 100 Mbit/s while the client physically moves at high speeds relative to the station, and 1 Gbit/s while client and station are in relatively fixed positions Dynamically share and use the network resources to support more simultaneous users per cell Scalable channel bandwidth 5–20 MHz, optionally up to 40 MHz Peak link spectral efficiency of 15 bit/s/Hz in the downlink, and 6.75 bit/s/Hz in the uplink (meaning that 1 Gbit/s in the downlink should be possible over less than 67 MHz bandwidth) System spectral efficiency of up to 3 bit/s/Hz/cell in the downlink and 2.25 bit/s/Hz/cell for indoor usage Seamless connectivity and global roaming across multiple networks with smooth handovers Ability to offer high quality of service for multimedia support

Key features of IMT-Advanced a high degree of commonality of functionality worldwide while retaining the flexibility to support a wide range of services and applications in a cost efficient manner compatibility of services within IMT and with fixed networks capability of interworking with other radio access systems high quality mobile services user equipment suitable for worldwide use user-friendly applications, services and equipment worldwide roaming capability enhanced peak data rates to support advanced services and applications 100 Mbit/s for high and 1 Gbit/s for low mobility were established as targets for research

Principal technologies MIMO: To attain ultra high spectral efficiency by means of spatial processing including multi-antenna and multi-user MIMO Frequency-domain-equalization, for example Multi-carrier modulation (OFDM) in the downlink or single-carrier frequency-domain-equalization (SC-FDE) in the uplink: To exploit the frequency selective channel property without complex equalization Frequency-domain statistical multiplexing, for example (OFDMA) or (Single-carrier FDMA) (SC-FDMA, Linearly precoded OFDMA, LP-OFDMA) in the uplink: Variable bit rate by assigning different sub-channels to different users based on the channel conditions Turbo principle error-correcting codes: To minimize the required SNR at the reception side Channel-dependent scheduling: To utilize the time-varying channel Link adaptation: Adaptive modulation and error-correcting codes Relaying, including fixed relay networks (FRNs), and the cooperative relaying concept, known as multi-mode protocol

Candidate systems The first set of 3GPP requirements on LTE Advanced was approved in June 2008 On October 21, 2010, ITU-R Working Party 5D has completed the assessment of six candidate submissions for the global 4G mobile wireless broadband technology (IMT-Advanced) Harmonization among these proposals has resulted in two technologies, “LTE-Advanced” and “WirelessMAN-Advanced” (WiMAX Release 2, IEEE 802.16m-2011) being accorded the official designation of IMT-Advanced, qualifying them as true 4G technologies On December 6, 2010, ITU noted that while current versions of LTE, WiMax and other evolved 3G technologies (e.g., HSPA+) do not fulfill IMT-Advanced requirements for 4G, some may use the term "4G" in an "undefined" fashion to represent forerunners to IMT-Advanced that show "a substantial level of improvement in performance and capabilities with respect to the initial third generation systems now deployed"

IMT-Advanced技術趨勢演進

4G 技術標準 LTE Advanced（長期演進技術升級版） WiMAX-Advanced（全球互通微波存取升級版） LTE FDD（分頻雙工長期演進技術） LTE TDD（分時雙工長期演進技術）又稱TD-LTE 由上海貝爾、諾基亞西門子通訊、大唐電信、華為技術、中興通訊、中國移動、高通、ST-Ericsson等業者共同開發 WiMAX-Advanced（全球互通微波存取升級版） IEEE 802.16m是WiMAX的增強，由WiMAX Forum所主導

台灣 4G LTE 業者 電信業者 頻率 (MHz) 中華電信 895-905MHz / 940-950MHz 台灣大哥大 733-748MHz / 788-803MHz 1710-1725MHz / 1805-1820MHz 台灣之星 885-895MHz / 930-940MHz 亞太電信 703-713MHz / 758-768MHz 國碁電子（與亞太電信合併） 723-733MHz / 778-788MHz 905-915MHz / 950-960MHz 遠傳電信 713-723MHz / 768-778MHz 1735-1745MHz / 1830-1840MHz 1745-1755MHz / 1840-1850MHz

LTE Standardization effort started in late 2004 LTE focus: With HSPA (downlink and uplink), UTRA will remain highly competitive for several years IEEE is standardizing mobile WiMAX => Threat for loosing competitive edge LTE focus: Enhancement of the UTRA Optimisation of the UTRAN architecture To ensure the continued competitiveness of the 3GPP technologies for the future LTE was the first technology recognized by the Next Generation Mobile Network alliance to meet its broad requirements

Key Features of LTE Many different bands: 700/1500/1700/2100/2600 MHz Flexible Bandwidth: 1.4/3/5/10/15/20 MHz Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) => Both paired and unpaired spectrum 4x4 MIMO, Multi-user collaborative MIMO Beamforming in the downlink Data Rate: 326 Mbps/down 86 Mbps up (4x4 MIMO 20 MHz) Modulation: OFDM with QPSK, 16 QAM, 64 QAM OFDMA downlink, Single Carrier Frequency Division Multiple Access (SC- FDMA) uplink Hybrid ARQ Transmission Short Frame Sizes of 10ms and 1ms => faster feedback and better efficiency at high speed Persistent scheduling to reduce control channel overhead for low bit rate voice transmission IP based flat network architecture

Elements of the LTE System LTE encompasses the evolution of Radio access through E-UTRAN (eNodeB) Non-radio aspects under the term System Architecture Evolution (SAE) Entire system composed of LTE & SAE is called Evolved Packet System (EPS) At a high level a LTE network is composed of Access network comprised of E-UTRAN Core Network called Evolved Packet Core (EPC)

LTE Network Elements UE – User Equipment used to connect to the EPS (Evolved Packet System) Access Network ENB (eNodeB) – The evolved RAN consists of single node, the eNodeB that interfaces with UE; The eNodeB hosts the PHY, MAC, RLC & RRC layers; It handles radio resource management & scheduling Core Network (Evolved Packet Core-EPC) MME (Mobility Management Entity) – Performs paging, chooses the SGW during UE attach S-GW (Serving Gateway) – routes & and forwards user data packets P-GW (Packet Gateway) – provides connectivity between the UE and the external packet networks

LTE Network Architecture

New Functionalities of LTE-Advanced (LTE Release10) Carrier Aggregation Multiple Input Multiple Output (MIMO) (Spatial Multiplexing) Relay Nodes Coordinated Multi Point operation (CoMP) – R11

Carrier Aggregation

Multiple Input Multiple Output (MIMO)

Relay Nodes

Coordinated Multi Point operation (CoMP)