Lte

LTE Wireless layer protocol introducedContents 1. What is LTE 2. SAE network structure Introduction 3. LTE wireless layer protocol architecture 本 PPT 使用资料的截止时间： 2006.04 一 . 什么是 LTE Abbreviation for Long Term Evolution Of LTE & SAE For long-term (10 years or longer) to ensure the competitiveness of the 3GPP Change the network architecture New air interface technology Reduce system complexity And heterogeneous systems LTE 的目标 Reduce the delay of the user plane and control plane delay (see next page) Higher downlink rate --- the DL 100Mbps / UL 50Mbps Support the optimization of the PS domain Higher system capacity (active> = 200/Cell the 5M spectrum) Better coverage (5km-30km-100km) Lower cost of deployment One-way delay of the user plane latency: RAN / the UE's IP layer User plane latency less than 5ms (no-load network + the tabloids text) Control plane latency: Less than 50msec Active (Cell_DCH) Dormant (Cell_PCH) Less than 100msec Camped-state (idle) . SAE network structure Introduction GERAN Gb Iu GPRS Core S3 S4 S7 PCRF Rx+ UTRAN HSS Evolved RAN S1 MME UPE S5 S6 Inter AS Anchor Gi Evolved Packet Core S2 S2 Op. etc…) non 3GPP IP Access * Color coding: red indicates new funct WLAN 3GPP IP Acces s ional element / interface . (IMS. IP Serv. PSS.二 . mobility management Stored UE control plane context. the state.About MME functional body . TA Mobility management Authentication and key management Signaling encryption. including the UE ID. integrity protection Management and distribution of user temporary ID . UPE 功能体简介—用户面处理  数据的路由和转发  用户面加密终结点  头压缩  存储 UE 用户面上下文，包括基本 IP 承载信息 、路由信息等  eNB 间切换 (3GPP AS 间切换 ) 用户面支持  LTE_IDLE 时下行数据触发 / 发起 paging . IASA 功能体简介—系统间用户面支持  处理不同接入系统间的用户面切换  数据的路由和转发  计费数据收集  到 PDN 的网关功能  部分功能可能和 UPE 合作 . LTE 的连接状态  LTE_Detached 网络没有 UE 的信息  LTE_IDLE 网络知道 UE 的 TA( 见下页 ) UE 进行 Cell/TA 更新  LTE_ACTIVE UE 可进行数传 网络和 UE 协作进行移动性处理 . Tracking Area  GSM: LA/RA ； UMTS: URA  LTE 使用统一的 TA 概念  LTE_IDLE 时网络对 UE 位置的知识精度为 TA  TA 边界 TA Update 信令过多的解决方式： 一个小区属于多个 TA 一个 UE 属于多个 TA . UE.g. server) End-to-End Service SAE Bearer Service external Bearer Service SAE Radio Bearer Service SAE Access Bearer Service Physical Radio Bearer Service Physical Bearer Service .SAE 的承载概念 SAE System UE eNodeB AGW Peer entity (e. LTE 无线层协议架构 降低系统的复杂性  减少传输信道个数 ( 如使用共享信道，删除 DCH)  减少 MAC 层实体个数 ( 如删除 MAC-d)  删除 BMC 层以及 CTCH( 使用 MBMS 代替 )  删除下行宏分集  删除 UTRAN 的压缩模式 ( 使用 scheduling gap)  RRC 的简化 ( 如删除 CELL_FACH 态 ) .三 . E-UTRAN 网络结构  eNB---E-UTRAN NodeB  aGW---E-UTRAN Access Gateway  E-UTRAN 由 eNB 组成  eNB 提供 RLC/MAC/PHY & RRC 功能  eNB 通过 S1 和 aGW 连接  可能在 eNB 以上存在 RRM Server 节点 . eNB Inter Cell RRM Connection Mobility Cont . RB Control Radio Admission Control eNB Measurement Configuration & Provision Dynamic Resource Allocation (Scheduler) RRC RLC MAC PHY S1 PDCP User Plane internet RRM Server (optional) Inter-Cell RRM Database (optional) aGW Control Plane SAE Bearer Control MM Entity aGW User Plane . eNB 功能  UE attach 时的 aGW 选择  调度和传输 paging messages  调度和传输 BCCH 信息  上下行资源分配  RB 控制、无线资源准入  LTE_ACTIVE 时的移动性管理 . aGW 功能 ( 参考前面 MME 、 UPE 、 IASA 功能 )  发起寻呼  LTE_IDLE 态 UE 信息管理  移动性管理  用户面加密处理  PDCP  SAE Bearer 控制  NAS 信令的加密和完整性保护 . 用户面协议栈 UE PDCP RLC MAC PHY RLC MAC PHY eNB aGW PDCP . DL based on OFDMA . DL based on OFDMA  FDD: UL based on OFDMA.物理层选择  FDD: UL based on SC-FDMA. DL based on OFDMA  FDD: UL/DL based on MC-WCDMA  TDD: UL/DL based on MC-TD-SCDMA  TDD: UL/DL based on OFDMA  TDD: UL based on SC-FDMA. 下行传输信道  BCH---Broadcast Channel  PCH---Paging Channel  DL-SCH---Downlink Shared Channel  NCH---Notification Channel (FFS)  MCH---Multicast Channel (FFS) 上行传输信道  UL-SCH---Uplink Shared Channel  RACH---Random Access Channel (FFS) . ARQ .. Segm.. ARQ Segm.. ARQ . ARQ BCCH PCCH Scheduling / Priority Handling MAC Multiplexing UE 1 Multiplexing UE n HARQ HARQ Transport Channels ..网络侧 L2 下行示意图 SAE Bearers ROHC PDCP Ciphering Ciphering Ciphering Ciphering ROHC ROHC ROHC Radio Bearers RLC Segm. Logical Channels Segm. .. Segm. ARQ . ARQ Logical Channels Logical Channels Scheduling / Priority Handling MAC Multiplexing HARQ RACH Transport Channels .UE 侧 L2 上行示意图 SAE Bearers ROHC PDCP Ciphering Ciphering ROHC Radio Bearers RLC Segm. MAC 层功能 ( 网络侧每 Cell 一个 MAC 实体 )  逻辑信道和传输信道的映射，复用和解复用  数据量测量  HARQ 功能  UE 内的优先级调度和 UE 间的优先级调度  TF 选择  Padding (FFS)  RLC PDU 的按序提交 (FFS) . 逻辑信道  BCCH---Broadcast Control Channel  P(N)CCH---Paging (and Notification) Control Channel  CCCH---Common Control Channel (FFS)  MCCH---Multicast Control Channel (FFS)  DCCH---Dedicated Control Channel  DTCH---Dedicated Traffic Channel  MTCH---Multicast Traffic Channel . 逻辑信道和传输信道的映射 PCCH BCCH CCCH DCCH DTCH MCCH MTCH Logical channels Transport channels PCH BCH RACH SCH MCH . RLC 层功能  支持 AM 、 UM 、 TM 数据传输 (FFS)  ARQ  数据切分 ( 重切分 ) 和重组 ( 级联 FFS)  SDU 的按序投递  数据的重复检测  协议错误检测和恢复 (Reset FFS)  aGW 和 eNB 间的流控 (FFS)  SDU 丢弃 (FFS) . PDCP 层功能—位于 UPE  头头头，只支持 ROHC 算法  用户面数据加密 (FFS)  下层 RLC 按序投递时， PDCP 的重排缓冲 (FFS ，主要用于跨 eNB 切换 ) . 控制面协议栈 UE NAS RRC RLC MAC PHY RRC RLC MAC PHY eNB aGW NAS . NAS 功能  SAE bearer 管理  鉴权  aGW 和 UE 间信令加密控制  用户面信令加密控制  移头性管理  LTE_IDLE 时的寻呼发起 . RRC 层功能  系统消息广播和寻呼  建立、管理、头放 RRC 连接  RRC 信令的加密和完整性保护 (FFS)  RB 管理  移动性管理  广播 / 多播服头支持 (FFS)  NAS 直传信令传递 (FFS) . RRC 连接状态  RRC_IDLE eNB 不存储 UE 上下文 对应 LTE_IDLE  RRC_CONNECTED eNB 有 UE 上下文 网络侧知道 UE 的 Cell 级位置 可进行数传 对应 LTE_ACTIVE . Perform Authentication . TMSI . TA-ID.状态转换图 Inactivity .IMSI UE position: .Cell reselection DL activity: .Allocate DRX for PCH Power-Up Perform “Registration” .Allocate C-RNTI Change of PLMN/deregistration .Known by network at cell level Mobility: .None New traffic . IP address .ID unique in cell (C-RNTI) .PLMN/Cell selection DL/UL activity: .Allocate C-RNTI.Handover DL/UL activity: .1 or more IP addresses UE position: .ID unique in Tracking Area (TA-ID) . TMSI .Deallocate TA-ID.ID unique in Tracking Area (TA-ID) .Does not exist Allocated UE-Id(s): . security key information) Allocated UE-Id(s): .Not known by network Mobility .Release C-RNTI .UE is configured with DRX period LTE_ACTIVE RRC: RRC_CONNECTED RRC Context in network: .IMSI.Establish security relation LTE_IDLE RRC: RRC_IDLE Context in network: . TA-ID.Known by network at Tracking Area (TA) level Mobility: .Includes all information necessary for communication Allocated UE-Id(s): .g.1 or more IP addresses UE position: .Deallocate C-RNTI. TMSI.IMSI. IP address .UE may be configured with DRX/DTX periods LTE_DETACHED RRC: NULL RRC Context in network: . IP address Timeout of periodic TA-update .Includes information to enable fast transition to LTE_ACTIVE (e. UE ID  IMSI & IMEI  TMSI for MME  TMSI for UPE (FFS)  C-RNTI  Random value for contention resolution . HARQ & ARQ  N-Channel 停等式 HARQ  HARQ 下行基于异步重传 ( 类似 HSDPA)  HARQ 上行基于同步重传 ( 类似 HSUPA)  RLC ARQ 进行 RLC SDU 或 PDU 重传 (FFS)  RLC ARQ 可基于状头头 告或 HARQ 信息 . 数据调度  MAC 头头头源分配  DL-SCH 和 UL-SCH 使用不同的 scheduler  UE 通过 scheduling channel 接收资源分配  调度基于待发数据量和无线质量、 QoS  除传统测量外，可增加额外测量 ( 如区分小区中 心和边缘， FFS) . E-UTRAN 移动性管理 RRC_CONNECTED 状态：  UE 根据网络的测量控制和邻区信息进行测量  网络侧控制上报准则 ( 周期触发 FFS)  网络侧控制 HO RRC_IDLE 状态：  小区重选过程 .  基本公共信息占用频带不能超过 UE 最小能力  HO 和频率重配  邻区列表不区分同频、异频 频带分布示意图： BS TX CCH TX UE1 RX UE2 RX UE3 RX UE4 RX BS TX CCH TX BS CCH TX TX UE5 RX BS CCH TX TX UE6 RX BS CCH TX TX UE7 RX 20 MHz Cell A Cell B Cell C Cell D Cell E .  Non gap assisted measurement (for handover)  Gap assisted measurement (for handover)  使用哪种方式依赖于 UE 能力和频带分布  UE 决定是否需要 gap  网络侧需要知道 UE 的测量方式，指导 scheduler  Gap 的获得方式： DRX/DTX 或 packet scheduling . .UTRAN 和 E-UTRAN 间的切换 UTRAN CELL_DCH E-UTRAN RRC_CONNECTED 1. UTRAN RRC Connected Configuration Stored CELL/URA_PCH LTE MM Idle Configuration Stored 3. CELL_FACH RRC_IDLE 2. IDLE LTE MM Idle Configuration Stored UMTS MM Configuration Stored 4.  E-UTRAN 和 UTRAN 间可切换  E-UTRAN 和 GERAN 间， FFS  UTRAN CELL_DCHE-UTRAN RRC_CONNECTED  UTRAN CELL_FACHE-UTRAN RRC_IDLE  UTRAN CELL/URA_PCHE-UTRAN RRC_IDLE  UTRAN RRC_IDLEE-UTRAN RRC_IDLE . The activation/deactivation of ciphering of the U-Plane is not controlled by the eNB NOTE 3: Key set for RRC protection cannot be used to derive NAS and user-plane keys. . NOTE 2: The protocol stack layer in which the ciphering takes place is FFS.鉴权和加密终结点 Ciphering NAS Signalling U-Plane Data RRC Signalling (AS) MAC Signalling (AS) Required and terminated above eNB (NOTE 1) Required and terminated in aGW (NOTE 2) Need is FFS Need is FFS Integrity Protection Required and terminated above eNB (NOTE 1) Need is FFS Required and terminated in eNB (NOTE 3) Need is FFS NOTE 1: “Above eNB” means that the termination point is in either the aGW or above (FFS) and that the activation/deactivation is not controlled by the eNB. 2 [3] 3GPP TR 25.814 1.参考文献 [1] 3GPP TS 25.3.0 draft .813 0.0 [2] 3GPP TS 25.882 1.2.3 [4] 3GPP TR 23.8.1.913 7.