LTE 网络基础总结

EPS (Evolved Packet System) Network Architecture & Protocol

这里收集了LTE网络的基础知识，大部分都是图片，方便理解和记忆。

1  网络演进方向

• All-IP based
• Reduced network cost
• Reduce data latency and signaling load
• Better network topology scalability and reliability
• Inteworking and seamless mobility among heterogeneous Access Netwroks
• Better always-on user experience
• Simpler and more flexible Qos support
• Higher level of security

网络演进

PS域演进

2  EPS 网络实体及接口

LTE网络实体图 

EUTRAN图及包含实体

eNodeB 作用
          1     Radio Resource Management

          2     IP header compression

          3     MME selection

          4     E-UTRAN synchronization and interference control

          5     User Plane Data routing

          6     Encryption procetion of user data




EPC图及包含实体

MME 作用

         1     NAS signaling and its security

         2     AS security control

         3     MME selection in handover

         4     S-GW/P-GW selection

         5     Romaing and Autherication

         6     Tracking Area List Management

         7     EPS bear management

         8     Inter CN node signaling for mobility between 3GPP Access Network



S-GW 作用

         1    E-UTRAN and 3GPP Access anchoring

         2    E-UTRAN IDEL model DL data buffing

         3    Package routing and forwarding

         4    Transport level Qos

         5    UL and DL charging per UE PDN and CQI


P-GW 作用

         1    IP address allocation

         2    Transport level Qos

         3    Package filter

         4    User Plan anchoring for 3GPP <-> Non 3GPP

3  EPS 用户和控制面的协议栈

S1 Control Plan protocol Stack

UE  -  eNodeB  -  MME

MME  -  HSS

MME  -  S-GW

User Plan

UE  -  SGW  -  PGW

4 EPS NAS Overview

包括协议 

-    EMM:   Evolved Mobility Management

-    ESM:    Evolved Session Management


基本过程
EMM 
Registration Procedure
    -    Attach, Detach
    -    Tracking Area Update


Security Procedure
    -    UE Identity Reallocation
    -    UE Identification
    -    Security Model Control
    -    EMM Information
    -    Authentication


EMM Connection Procedure
    -     SMS
    -     Paging
    -     Service Request

ESM
EPC to UE
    -    Default EPS bearer activation
    -    Dedicate EPS bearer activation
    -    EPS bearer modification
    -    EPS bearer deactivication



UE to EPC
    -     UE requeset PDN connectivity
    -    UE requeset PDN modification
    -    UE requeset PDN disconnectivity


EPS Network Topology

一些概念和图可以对应起来，从图上看比较直观，比背诵概念要强些。

Tracking Area:  

MME Area:  

MME-Pool:  

EPS Idle and Active States 状态迁移

EPS Idle and Active States Use Case