System Architecture

2018 Fall

Intro LTE (Chap1 and

part of Chap2)

Tomohisa Wada

Information Engineering

1

Previous LTE : two different radio waves

UMTS：Universal Mobile Communication System

GSM：Global System for Mobile Communications

2

Circuit Switch

Public Switch

Telephone

Network

Voice Call

Packet Switch

Web Email

Packet Data

Network

Constant Data Rate

& Minimum DelayGSM EDGE

radio access

network

UMTS

terrestrial

radio access

network

User Equipment

Detail of Air Interface (UMTS)

FDD: frequency division duplex

TDD: time division duplex

3

cell

celll

cellRadio Network Controller

1) Pass voice and packet amaong Node Bs

and Core network

2) Controll mobiles by signals

Review of OSI model

4

TRANSPORT LAYER

TCP(transmission control protocol):

does re-transmit.

Web, email etc.

UDP(user datagram protocol): no re-

transmit

Real time voice and video

NETWORK LAYER

IP(internet protocol): send packet

using IP address.

LTE is much simple : data main

No circuit switch in LTE

IP multimedia subsystem (IMS)

supports voice over IP call.

5

Evolved Packet Core

Key features of air interface

6

Key features

7

Number of all subscriptions

8

LTE subscriptions

9

3GPP specs

10

FDD

frequency

11

TDD

frequency

12

Freq used by LTE (2013)

13