4G Introduction

4GA historical and practical guide

PrologueEvolution To Mobile Operator

10 MHz

Set up a podcast to provide your family weekend entertainment, kind of like a 1G provider


1 MHz

now neighbors want to join

You use FDMA to provide 10 neighbors


1 MHz

more neighbors want to join

You use TDMA on each 1MHz carrierbecause not everyone is using

it the same time anyway


Far far away friends want to join

Mobility, security, policy control, planning… Congratulations! You are now a mobile operator!

A Little History: 1G• 1980

• Lack of roaming: various local systems

• Bad security

• Poor battery

https://img1.etsystatic.com/005/0/6011536/il_340x270.400991407_ig0s.jpg

https://img1.etsystatic.com/005/0/6011536/il_340x270.400991407_ig0s.jpg

A Little History: 2G• 1990, it’s all about voice, good voice and roaming voice

• GSM: Global System for Mobile Communications, the success of mobile

• FDD/TDMA-FDMA

• SMS

• 10^2 kbit/s

http://upload.wikimedia.org/wikipedia/commons/thumb/d/d1/Gsm_structures.svg/350px-Gsm_structures.svg.png

http://upload.wikimedia.org/wikipedia/commons/thumb/d/d1/Gsm_structures.svg/350px-Gsm_structures.svg.png

Problem of 2G

• 2G focus on voice, results in an air interface very inefficient for data packet

• Various advances in MAC layer technology, notably CDMA

Voice Data

Bit Rate small CBR Variable BRCan be large

Band Width 64 Kbit/s 2Mbit/s

Packet small large

Delay small depends

CDMA• Better auto correlation

• Low cross correlation between different spread code’s output signal

• Frequency reuse factor of 1 (as oppose to 4 in GSM)

• Improved security

• Hard to be jammed

Input Signal

Spreading Code

Output Signal

A Little History: 3GThe Vision

The Martini Vision: Anyone, Anywhere, Any Medium

A Little History: 3G

IMT 2000 family Common term mode of operation

中華電信

IMT-DSDirect Sequence

CDMAW-CDMA FDD v

IMT-MCMulti Carrier

CDMACdma2000 FDD v

IMT-TDTime Devision

CDMATD-CDMA TD-SCDMA TDD

IMT-SCSingle Carrier EDGE FDD

IMT-FTFrequency Time DECT TDD

In Reality

3G: UMTSUniversal Mobile Telecommunications System

UE NodeB SGSN GGSNInternet

HLR

MSC GMSC

User Equipment

Serving GPRSSupport Node

Gateway GPRSSupport Node

Packet Data Network(packet Switch Stream, IP Multimedia System)

UTRAN Core Network

UE NodeB

UE NodeB

RNC

RNC

Public Phone

Network

Signaling Network

Mobile Switching Center

Gateway MSC

Home Location Register

Radio Network

Controller



HLR

MSC GMSC

User Equipment




UTRAN Core Network

RNC

Public Phone

Network

Signaling Network


Gateway MSC


• You bought a phone right outside NTHU, turn it on

• Your subscription is based on a 15 digits number in your SIM.

• After the phone found network, the number is sent to HLR.

• Your phone and HLR now share the same key for communication.

Radio Network

Controller



HLR

MSC GMSC

User Equipment




UTRAN Core Network

RNCRadio

Network Controller

Public Phone

Network

Signaling Network


Gateway MSC


• First you make a call to inform your dad 付清節快樂 (happy father’s paying day)

• Your UE requests MSC about a particular number.

• MSC checks with HLR to see if you are permitted to call.

• MSC set up resources required in RAN (radio access network) and CN (core network).

• When the call ends, MSC and GMSC are involved in producing call detail record.



HLR

MSC GMSC

User Equipment




UTRAN Core Network

RNCRadio

Network Controller

Public Phone

Network

Signaling Network


Gateway MSC


• Now you are riding your scooter back to NCTU.

• After a while idle, your phone moves from Mobility Management (MM) connect to MM-IDLE. To avoid excessive location update, few NodeB’s are grouped into a location area. Location update happens only when you enter new location area.

• So your phone happily sits idle and listen if it receives call or location update.



HLR

MSC GMSC

User Equipment




UTRAN Core Network

RNCRadio

Network Controller

Public Phone

Network

Signaling Network


Gateway MSC


• When your dad tries to call you (he decides he don’t won’t to pay for this cell phone), GMSC looks up HLR to see which MSC is serving you. All NodeB’s of that location area broadcast to wake up your cellphone.

• During call, you are constantly moving, so hand over is required. In CDMA, you are often connected to multiple cell towers at once, this facilitates soft handover.



HLR

MSC GMSC

User Equipment




UTRAN Core Network

RNCRadio

Network Controller

Public Phone

Network

Signaling Network


Gateway MSC


• Now you are wondering what is RNC, so you open your browser.

• To send or receive packets, a PDP (packet data protocol) context need to be established.

• PDP context signals SGSN and GGSN to set up context for packet data session. Context include a subscriber IP and a QoS request.

• After done browsing, you deactivates the PDP context.



HLR

MSC GMSC

User Equipment




UTRAN Core Network

RNCRadio

Network Controller

Public Phone

Network

Signaling Network


Gateway MSC


• QoS request is simply ignored by most (all) operators.



HLR

MSC GMSC

User Equipment




UTRAN Core Network

RNCRadio

Network Controller

Public Phone

Network

Signaling Network


Gateway MSC


• Now mobile operator is sending you a SMS message to inform about the data usage volume.

• GGSN checks HLR to obtain your routing area, but also obtains that you have no PDP context active. A paging message is broadcast requesting your phone to set up PDP context so that the message can be sent.

Key notes on 2G/3G2G 3G

Data Rate 10 kbit/s 10 kbits/s

MAC Scheme TDMAFDMA CDMA

Available Bandwidth

2x5 MHzwith TDMA 2x15 MHz

Cost and Market see next few slides

2 4

Bandwidth: 2G vs 3Gtype bandwidth winning bid

(in billion) winner

A W-CDMA 2 x 15MHz+ 5MHz 10.2 遠致

B W-CDMA 2 x 10MHz+ 5MHz 7.7 聯邦

C W-CDMA 2 x 15MHz+ 5MHz 10.3 台灣

D W-CDMA 2 x 15MHz+ 5MHz 10.2 中華

E CDMA2000 2 x 20MHz 10.6 亞太

2G1. About to be “recycled”

2. At the time CHT got its 2G license. It is still government run.

3G: around 49 billion NTD

Revenue: 2G vs 3G

3G growth

• Question: Why is it growing like this? Slow, exponential, finally slow.

Problem with 3G• Why has it been slow to take off?

Small coverage, lack of cheap and power friendly terminal, lack of killer app

• W-CDMA cell breathing frequency reuse factor of 1 -> all senders and receivers interfere with each other-> number of UE affects edge data rate-> making cell tower planning more difficult

• Packet network scalabilityGGSN is a huge gateway that last for a long time (it is not just a bottle neck, it is a static battle neck…)

LTE• It is not 4G

ITU made it clear… LTE is part of IMT-2000 3G family. We call LTE 3.9G, because despite its enormous improvement on bandwidth (around 50 Mbit/s), it did not meet 4G standard (100 Mbit/s).

• It is designed to expect an all-packet-switching network.3G was designed for both, but is in fact very inefficient on IP.

• TLACongratulations, you are ready for more TLA’s (three letter acronym).

3GPP

LTE

EPS

E-UTRAN

SAE

EPC

Release 8

Third Generation Partnership Project

Long Term Evolution System Architecture Evolution

Evolved Packet CoreEvolved UTRAN

Evolved Packet System

3GPP

LTE

EPS

E-UTRAN

SAE

EPC

Release 8





Term used for marketing

3GPP

LTE

EPS

E-UTRAN

SAE

EPC

Release 8





Terms withactual meaning

Terms withactual meaning

Term should have been used

for marketing

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC

User Equipment Evolved NodeB Serving Gateway PDN Gateway Packet Data Network(packet Switch Stream, IP Multimedia System)

E-UTRAN Core Network (EPC)

MobilityManagement

Entity

HomeSubscriber

Server

Evolved ServingMobile Location Center

Gateway MobileLocation Center

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



So called “cell phone” but could be other devices

On a UE, UMSI: Unique Mobility Subscriber Id identifies a subscriber. UMEI: Unique Mobility Equipment Id identifies equipment. UMEI can be obtained by typing *#06#

EPS Architecture

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC


MobilityManagement

Entity

HomeSubscriber

Server



So called “cell tower”

e-NodeB • Provide radio access to UE’s (Uu interface). • Interface: logical connection between

endpoint.

Uu

S1-MME

S1-U


EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Control Traffic

Uu S1-U

S1-MME

Data

e-NodeB • Separate control plan and data plan. • Tunnels control traffic between UE and MME

(S1-MME interface). • Tunnels data between UE and services

(S1-U interface).


EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Control Traffic

Uu S1-U

S1-MME

Data

e-NodeB • Concert with other eNodeB’s to handle

mobility (X-2 interface).


UEUser Equipment

Uue-NodeB

X-2

Control Traffic

Data

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Uu S1-U

S1-MME

MME • Keep track of UE’s. • Setting up and tearing down sessions.

S11

S6a

S5 SGi

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Uu S1-U

S1-MME

MME • Authentication and gate keeping.

S11

S6a

S5 SGi

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Uu S1-U

S1-MME

MME • Selecting S-GW and P-GW. • Primary responsibilities are divided into

EMM (Evolved Mobility Management) and ESM (Evolved Session Management).

• A user is on al most one MME at all time.

S11

S6a

S5 SGi

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Uu S1-U

S1-MME

HSS • Database of subscriber information. • Queried by MME. • Holds security information of all SIM cards

of a mobile network. • Keeps a “birds eye view” of what users are

located in what network (i.e. what SIM is registered with which MME). Similar to HLR in UMTS.

S11

S6a

S5 SGi

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Uu S1-U

S1-MME

S-GW • One or more S-GW’s can serve one or more

eNB’s. • One UE can be served by only one S-GW. • Receives instructions from MME to self up

and teardown UE sessions. • Handle signaling between MME and P-GW. • Handle IP packet between UE and P-GW.

S11

S6a

S5 SGi

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Uu S1-U

S1-MME

S-GW • One or more S-GW’s can serve one or more

eNB’s. • One UE can be served by only one S-GW. • Receives instructions from MME to self up

and teardown UE sessions.

S11

S6a

S5 SGi

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Uu S1-U

S1-MME

S-GW • Handle signaling between MME and P-GW.

S11

S6a

S5 SGi

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Uu S1-U

S1-MME

S-GW • Handle IP packet between UE and P-GW.

S11

S6a

S5 SGi

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Uu S1-U

S1-MME

P-GW • Provide access to external PDN • One UE can be associated with multiple P-

GW if it connect to multiple PDN’s. • Dictates the QoS and bandwidth parameter

for subscriber’s session.

S11

S6a

S5 SGi

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Uu S1-U

S1-MME

PCRS • The core function of a PCRF is to make

policy decisions for the network.That means it needs inputs (eg: from a subscriber database, from real-time network information, from a billing system, from local configuration) and it needs to translate that into a decision to direct the policy enforcer (PCEF) to take appropriate actions.

S11

S6a

S5 SGi

EPS Architecture

PCRS

Gx

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Uu S1-U

S1-MME

PCRS • What is the difference between PCRS and

PCEF in P-GW? • In CSFB, is PCRS involved? • Why can’t PCRS simply be a function of P-

GW?

S11

S6a

S5 SGi

EPS Architecture

PCRS

Gx

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server



Uu S1-U

S1-MME

AS vs NAS • AS (access stratum): link to link

communication. • NAS (non-access stratum): provide

communication between access network and core network. NAS makes the direct communication between MME and UE possible.

S11

S6a

S5 SGi

EPS Architecture

PCRS

Gx

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS

E-SMLC GMLC



MobilityManagement

Entity

HomeSubscriber

Server

Uu



S1-U

S1-MME

Control plan - - - - - - - - - - User plan - - - - - - - - - -

S11

S6a

S5 SGi

EPS Architecture

UE e-NodeB

MME

S-GW P-GW

PDN(PSS, IME)

HSS



MobilityManagement

Entity

HomeSubscriber

Server

Uu S1-U

S1-MMES11

S6a

S8 SGi

Roaming ScenarioRoaming User Foo

Visited Network (VPLMN,

visited PLMN)

Foo’s SubscribedNetwork (HPLMN, home public

land mobile network)

Architectural Comparison

UE e-NodeB

MME

S-GW P-GW

HSS

User Equipment Evolved NodeB Serving Gateway PDN Gateway

MobilityManagement

Entity

HomeSubscriber

Server

UE NodeB

SGSN GGSN

HLR

MSC GMSC

User Equipment



RNCRadio

Network Controller

Signaling Network


Gateway MSC


Control plan - - - - - - - - - - User plan - - - - - - - - - -


UE e-NodeB

MME

S-GW P-GW

HSS


MobilityManagement

Entity

HomeSubscriber

Server

UE NodeB

SGSN GGSN

HLR

MSC GMSC

User Equipment



RNCRadio

Network Controller

Signaling Network


Gateway MSC


With X-2 interface, eNodeB’s can communicate with each other to handle mobility, so RNC is merged into eNodeB.


UE e-NodeB

MME

S-GW P-GW

HSS


MobilityManagement

Entity

HomeSubscriber

Server

UE NodeB

SGSN GGSN

HLR

MSC GMSC

User Equipment



RNCRadio

Network Controller

Signaling Network


Gateway MSC


The forwarding function of MSC and SGSN is handled by S-GW, while the session management function is handled by MME.


UE e-NodeB

MME

S-GW P-GW

HSS


MobilityManagement

Entity

HomeSubscriber

Server

UE NodeB

SGSN GGSN

HLR

MSC GMSC

User Equipment



RNCRadio

Network Controller

Signaling Network


Gateway MSC


GMSC and GGSN correspond to P-GW and HLR correspond to HSS is pretty much accurate.

2013年度綜合財報

2014 第三季股東說明會講稿

2015 ⼀一⽉月份營運報告（內含2014⽉月營運報告）

Reference

1. 中華電信財務報表：http://www.cht.com.tw/ir/upload/files/CHT2013_AnnualReport_0528Chinese.PDF

2. Wisely, David. IP for 4G. John Wiley & Sons, 2009.

3. Kasera, Sumit, and Nishit Narang. 3G Mobile Networks: Architecture, Protocols and Procedures Based on 3GPP Specifications for UMTS WCDMA Networks. McGraw-Hill Professional Publishing, 2005.

4. Russell’s Youtube Channel: https://www.youtube.com/user/QuadraticSquared

http://www.cht.com.tw/ir/upload/files/CHT2013_AnnualReport_0528Chinese.PDF

https://www.youtube.com/user/QuadraticSquared

Engineering

4G Introduction