BLG609E Network Architecture+WiMAX Revised

8/3/2019 BLG609E Network Architecture+WiMAX Revised

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Alper Yegin, rfan Ali BLG 609E, 20121

Overview of Wireless NetworkArchitectures

February 2012

Alper Yegin

[email protected]

Irfan Ali

[email protected]


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Objective of this lecture

Understand the need of defining an architecture for wirelessnetworks

Get an understanding of the process of how standards are writtenand from where to get standards documents

Understand the evolution of GSM family of standardsCircuit Switch (CS) domainPacket Switch (PS) domain

Understand LTE architecture Understand WiMAX architecture Basic procedure of Attach (Registration) to illustrate how the entire

architecture works

LTE Long Term Evolution

WiMAX Worldwide Interoperabil ity for Microwave Access


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Overview of this lecture

Process of StandardsWhy a cellular network architecture?How is cellular network architecture defined?Components of architecture (protocols, interfaces, etc)From Lab to Standards to Products to Deployment

GSM (3GPP) family of StandardsGSM ArchitectureUMTS ArchitectureLTE Architecture

WiMAX Standard


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Story

Internet

Mobile

terminal

Base Station

Access

Gateway

Core

Gateway

Web

server

Network discoveryand selection

Network entry

Mobility

management

Location andpower management

Quality-ofservice

Interworking

Fault tolerance


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Why Standards?

Cell phones from a large number of cellphone vendors(Nokia, Samsung, Motorola, Apple, etc.) need to workwith infrastructure of a large number of infrastructure-

vendors (Ericsson, Nokia Siemens Networks (NSN),

Huawei, Alcatel-Lucent, Samsung, etc).

Need for an open and well specified interface between cellphonesand the infrastructure. Operators would like to buy infrastructure from different

vendors.

Need for open and well specified interfaces in the infrastructure. Law of large numbers Lower-cost systemOpen and well specified systems attract a large number of vendors

to build systems (networks and cell phones)


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How?

Operators and vendors form an open alliance to definespecifications (standards) for systemsDefining entire system

3GPP Alliance (GSM [ETSI], UMTS, LTE)3GPP2 Alliance (CDMA)WiMAX Forum (WiMAX)ITU (Fixed telephony network, SS7, )IETF (Internet, e.g.: IP, TCP, UDP, PPP, )

Defining limited-scope systemsIEEE (Ethernet, WiFi, 802.16m, RS 232, RS 485, etc)

3GPP 3rd Generation Partnership Project

WiMAX Worldwide Interoperability for Microwave Access

ETSI European Telecommunication Standards Institue

UMTS Universal Mobile Telecommunications System

CDMA Code Division Multiple Access

ITU International Telecommunications Union

IETF Internet Engineering Task Force

SS7 Signalling System 7

IEEE Institute of Electrical and Electronic Engineers


7/34Alper Yegin, rfan Ali BLG 609E, 20127

Systems Engineering and building blocks ofsystem model

Systems engineering is an interdisciplinary field of engineering thatfocuses on how complex engineering projects should be designedand managed over the life cycle of the project.

In this course we will be focused on the design of cell phone systems System: There are many definitions of what a system is in the field

of systems engineering. Below are a few authoritative definitions:

ANSI/EIA-632-1999: "An aggregation of end products and enablingproducts to achieve a given purpose."

IEEE Std 1220-1998: "A set or arrangement of elements and processesthat are related and whose behavior satisfies customer/operational needs

and provides for life cycle sustainment of the products."

ISO/IEC 15288:2008: "A combination of interacting elements organized toachieve one or more stated purposes."

Source: Wikipedia



Systems Engineering Process

Source: Wikipedia



Systems Engineering Process and StandardsProcess

Standards

ProcessService

Requirements

Technology

DesignO

bjectives

Internet Connectivity Service Continuity Quality of Service Authenticate and Authorization Secure connection

Radio technology (CDMA,OFDM, ..)

Security Mechanisms Hardware technology

Stage-1, Stage-2 and Stage-3Specs

Conformance testingspecification

Reduce cost Reduce complexity Based on existing Design

System

Specification

ProductDevelopment

Request forProposal

(RFP)

OperatorsVendors



The 3GPP Process of Developing a New System/Feature/Service

The process is applied to both big features e.g., LTEand to smaller features, e.g., Emergency-call support inLTE.

STAGE-1

Defines Service

requirements

STAGE-2

Defines architecture

network elements &

high level flows STAGE-3

Defines protocols

(state m/c,messages)

Timeline

Level ofDetail

Low

High

ConformanceTesting

Specifications

Stages are defined in ITU-T Specification Recommendation I.130.

http://www.itu.int/rec/T-REC-I.130/en



The 3GPP Standards Process applied to LTE

STAGE-1

Defines service

requirements STAGE-2

Defines architecture

network elements & high

level flows

Timeline

Level ofDetail

TR 25.913 Requirementsfor evolved UTRA andUTRAN

Rates: DL: 100 Mbps, UL: 50Mbps (for 20 MHz spectrum)

Control plane latency (idle->active < 100 ms)

TS 22.278 Servicerequirements for the

Evolved Packet System Support of non-3GPP accesses Differentiated quality of

Service.

TS 23.401 GRPS

Enhancements for E-UTRANAccess

Describes the overall LTE system

architecture

TS 36.300 E-UTRA & E-UTRANOverall Description

Describes the Radio AccessNetwork part of LTE

Large number of specs (key)

36.331 Radio Resource Control 24.301 Non Access Stratum (NAS) 24.274 Generic Tunneling Protocol

(GTP) ,

2Q 2004 March 20081Q 2005 Dec 2008

STAGE-3Defines protocols

(state m/c,

messages)

Stages are defined in ITU-T Specification Recommendation I.130.

http://www.itu.int/rec/T-REC-I.130/en

March 2007



What are the components of CommunicationSystem Architecture Specification?

A model of the system is created. An abstraction of reality designed to answer specific questions about the real world An imitation, analogue, or representation of a real world process or structure; or A conceptual, mathematical, or physical tool to assist a decision maker.

Key components of model description are: Block Diagrams: Block diagram is a diagram of a system, in which the principal parts or

functions are represented by blocks connected by lines, that show the relationships ofthe blocks. (a.k.a., NRM Network Reference Model)

Message Sequence Charts/ Sequence Diagrams: A sequence diagram shows objectinteractions arranged in time sequence. It depicts the objects and classes involved in

the scenario and the sequence of messages exchanged between the objects needed

to carry out the functionality of the scenario. (a.k.a., call flows)

Protocol level State Diagram: State diagrams model the system as composed of a finitenumber of states and the events that lead to transition between these states. (a.k.a.,

state machine)

Source: Wikipedia



Block Diagram example: LTEArchitecture

UE

MME

HSS

Serving

GWPDN GW

Operators IPServices

Internet

S6a

S11

S1u

S1-MME

LTE-Uu

S5

SGi

eNB

S10

X2

Online

Charging

Function

Onffline

Charging

Function

Billing

Domain

Ro

Rf

Bx

Functional EntityLogical Entity

Network Entity

InterfacesReference Points

SGi

eNB Enhanced Node B

MME Mobility Management Entity

S-GW Serving GatewayPDN GW Packet data network GW

HSS Home Subscriber System



14

Message Sequence Chart Example: Restaurant



15

State Diagram Example: Enhanced Mobility Management(EMM) States in Mobile for LTE

EMM-NULLEMM-TRACKING-

AREA-UPDATING-INITIATED

EMM-DEREGISTERED

- DETACH requested

(not power off)

EMM-REGISTERED

Any state

EMM-DEREGISTERED-

INITIATED

- ATTACH

requested

DETACH requested(power off)

- DETACH accepted- Lower layer failure

- TAU

requested

- TAU accepted- TAU failed

EMM-REGISTERED-

INITIATED

EMM-SERVICE-REQUEST-INITIATED

- SR accepted- SR failed

- SR initiated

-

TAU rejected(#13, #15, #25)

-

- ATTACH rejected

-Network init. DETACH requested-Lower layer failure

- enableS1 mode

- disable S1 andS101 mode

TAU rejected

(other causes)-

ATTACHaccepted and

default EPS bearer

context activated

-

- enable S1 andS101 mode

- disableS1 mode

-Network init. DETACH requested- local DETACH- intersystem change to cdma2000

HRPD completed

- SR rejected(#13, #15, #18,#25, #39)



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LTE/EPC Specifications

UE

MME

HSS

Serving

GW

PDN GW

PCRF

Internet

S6a

S11

S1u

S1-MME

LTE-Uu

S5

Gx

Rx

SGieNB

S10

X2

SPR

Sp

Stage-1SpecificationStage-2SpecificationStage-3Specification

Stage-1: 22.278

E-UTRAN Stage-2:36.300

Evolved Packet Core Stage 2: 23.401

29.274 GTPC

29.281 GTPU

29.274 GTPC

36.410 General

36.411 Layer 1

36.412 (Sig xport)

36.413 (S1AP)

29.212

29.213 Sig Flow

36.201,211,213,214 PHY

36.321 MAC

36.322 RLC

36.323 PDCP

36.331 RRC

36.410 General

36.411 Layer 1

36.414 (Data xport)

29.281 GTPU

PCC Stage 2: 23.203Charging Stage 2: 32.240

36.420 General

36.421 Layer 1

36.422 (Sig xport)

36.424 (Data xport)

36.423 (X2AP)

29.281 GTPU

29.214

36.304 Idle

36.306 Capability

36.314 Measurement

23.122 Idle-NAS

24.301 NAS

Unspecified

Online

Charging

Function

Offline

Charging

Function

Billing

Domain

Gy/Ro

Gz/Rf

Bx

32.251

32.251

General:

23.003 Identifiers

29.303 DNS

33.401 Security Stage 2&3

S9

29.215

29.061

29.272

36.133 RRM Reqds

OperatorServices

Link to get latest 3GPP specs per release: ftp://ftp.3gpp.org/Specs/latestLink to find out what a spec covers: http://www.3gpp.org/Specification-Numbering



17

Protocols and Architecture

A communications protocol is a formal description of message formats andthe rules for exchanging those messages (source: Wikipedia).

Protocol: A formal set of procedures that are adopted to ensurecommunication between two or more functions within the same layer of ahierarchy of functions (source: ITU-T I.112).

Protocols are typically created for meeting a simple function and assumesimple architecture, e.g.: Point to Point Protocol (PPP) (RFC 1661): Setting up serial link between a PPP

client and PPP Server

Mobile IPv6: IP-layer mobility support between an IPv6 client and a MIPv6 homeagent.

IEEE 802.16e: Physical and MAC layer protocols between two modems usingOFDM technology.

Network architecture is the design of a communications network to meet acomplex set of functionality.

It includes specifying functional elements, reference points between them,protocols running on those reference points, and the interactions.

3GPP LTE architecture WiMAX architecture 3GPP2 architecture



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Reference point, Interface and Protocols

Reference point: A conceptual point at the conjunction of two non-overlapping functional groups (source: ITU-T I.112).

Interface: The common boundary between two associated systems(source: ITU-T I.112). Terms reference point andinterface are used inter-changeably in

standards

One or more protocols are used on a reference point. In case of 3GPP up-to a maximum of one user-plane and one control-plane protocolis used on an interface For WiMAX, multiple protocols may exist on a reference point.

ASN

GW CSN

R3

R3MIPFAEAPauthr

AAAclient

MIPHA

EAPserver

AAAserverMIPv4, EAP, Radius

SGW PGW

S5

SGW PGW

S5

GTP

(GTPC + GTPU)

3GPP WiMAX

GPRS General Packet Radio System

GTP GPRS Tunneling Protocol

EAP Extensible Authentication ProtocolAAA Authentication Authorization and

Accounting



19

WiMAX Standard =

WiMAXForum

(full-stackend-to-endarchitecture

definedbyWMFNWG)

IEEE

(PHYandMAClayers

forairlinkdefinedby

IEEE802.16WG)

3GPP

(e.g.,PCC,IMS)

IETF

(e.g.,MIP,EAP,

DHCP,IPv6,etc.)

OMA

(e.g.,OMA-DM)

DSLF

(e.g.,TR-69)

IEEE Institute of Electrical and Electronics Engineers

WG Working Group

PCC Policy and Charging Control

IMS Internet Multimedia System

IETF Internet Engineering Task Force

MIP Mobile IP

OMA Open Mobile AllianceDM Device Management

DSLF Digital Subscriber Line Forum


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Packaging

IETF

WiMAXForum

NWG

IEEE802.16e

IETF

WiMAXstandards WiMAXproduct

IEEE802.16e

WiMAXForum

NWGWiMAXForum

NWG

IEEE802.16e

IETF

WiMAXdeployment


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Wireless Technology Lifecycle

Labresearch

Industryinterest

SDOTechnology

spec.

Productspec.

Product DeploymentMarket

use


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Iterations

Labresearch

Industryinterest

SDOTechnology

spec.

Productspec.


use


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Bumpy Ride

Labresearch

Industryinterest

SDOTechnology

spec.

Productspec.


use


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Source: Adapted from, Amitava Ghosh, WiMAX or LTE or what else and beyond IEEE Radio and Wireless Week, 18 22 Jan 2009

3GPP R9LTE,EPC

3GPP R10LTE-A

From Standards to Products

Samsung Craft

TeliaSonera, Sweden


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WiMAX Network Architecture


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WiMAX

WiMAX is a IEEE 802.16d/e/m standard-based technology enablingthe delivery of last mile mobile wireless access at broadband

speeds.

CharacteristicsBroadband (Rel. 1 primarily for 5 MHz. Rel 1.5 supports up-to 20 MHz)Orthogonal Frequency Division Multiple Access (OFDMA)All-IPNon-line of sightFixed, nomadic, and mobile deployment


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WiMAX Evolution

Source: Kamran Etemad, Overview of Mobile WiMAX Technology and Evolution, IEEE Communications Magazine, October 2008


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WiMAX Network Architecture: PS Domain only

Internet,

IMS

BS BS BS

ASN-GW(FA)

ASN-GW(FA)

MIP HA

R3

R8

Access Service Network(ASN)

R6

Connectivity Service Network(CSN)

AAA Server

R4

DHCP Server

R1

MS

NRM Network Reference Model


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WiMAX Network Architecture

Handover function

Paging agent

Authentication

relay

RRC

Service flow

management

OAM

Security

Context function

Inter BS Mobility

Anchoring

Foreign Agent

MS IP address

Allocation

BS

ASN-GW

MIP HA

R6

Authentication server

AAA Server

User-Plane

Functional Entity

Control-Plane

Functional Entity Radio Bearer

Transmission (L1/

L2/L3)

Subscription Inter ASN-GW

Mobility Anchoring

Internet,

IMS

BS BS BS

ASN-GW(FA)

ASN-GW(FA)

MIP HA

R3

R8

R6

AAA Server

R4

DHCP Server

R3

R1

MS

Paging controller

Host configuration

Functional Decomposition


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802.16 PHY

802.16 MAC

CS

IPv6 [IPv4]

802.16 PHY

802.16 MAC

CS

PHY

L2 / Intra ASN

Data Path

MS BS

PHY

IPv6 [IPv4]

L2 / Intra ASN

Data Path

PHY

IPv6 / IPv4

L2

PHY

IPv6 / IPv4

PMIPv6PMIPv6

L2

MAG LMA

R1 R6 R3/R5

Control and Data Planes

802.16 PHY

802.16 MAC

CS

IPv6 [IPv4]

802.16 PHY

802.16 MAC

CS

PHY

L2 / Intra ASN

Data Path

MS BS

PHY

IPv6 [IPv4]

L2 / Intra ASN

Data Path

PHY

GRE / IPv6 /IPv4

L2

PHY

GRE / IPv6 /IPv4

IPv6 [IPv4]IPv6 [IPv4]

L2

MAG LMA

PHY

IPv6 [IPv4]

L2

CN

R1 R6 R3

ASN CSN 3rd Party

(ASN-GW)

Protocol Stack

(ASN-GW)

(Core Router)

(Core Router)

Other end


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MS Performs attach Part 1 of 3

2. Ranging and PHY

adjustment

ASN-GW

3. SBC-REQ(MSID, Capabilities)

4. MS Pre-attachment Req

(MSID)

5. MS Pre-attachment

Resp6. SBC-RSP (Auth

framework)

7. MS Pre-attachment Ack

8.AuthRelay_EAP_Transfer

(EAP Payload: EAP Request/Identity)9. PKMv2-RSP/EAP

Transfer (EAP

Request/ Identity)

10. PKMv2-REQ/EAP-

Transfer(EAP Response/

Identity -NAI)11.AuthRelay_EAP_Transfer(

EAP Response / Identity-NAI)

BSMS

1. DL channel acqusition,

MAC synch, UL ch. params.

Call Flow


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LMA

InternetMS Performs Attach Part 2 of 3

AAAServer

BSMS

12. EAP Authentication Method(e.g. EAP-TTLS, EAP-TLS, EAP-AKA)

13 EAP Success is

indicated and security

context is acquired

14. AuthRelay_EAP_Transfer(EAP Payload, EAP-Success)

15. PKMv2-RSP/EAP-

Transfer(EAP Success)

24 Connections

Establishment (DSA-REQ/

RSP/ ACK)

25 Data Path Establishment

18. PKMv2 3whs, key req/

reply

16. Key_Change_Directive

(AK Context)

17. Key_Change_Ack

19. REG-REQ 20. MS Attachment

Request

21. MS Attachment Resp

22. REG-RSP

23. MS Attachment Ack

ASN-GW


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LMA

InternetMS Performs Attach Part 3 of 3

AAAServer

BSMS ASN-GW

26. Proxy Binding Update 27. Access Request

28. Access Accept

29. Proxy Binding Ack.

30. Router advertisement

31. DHCPv6 Solicit

32. DHCPv6 Advertise

33. DHCPv6 Request

34. DHCPv6 Reply


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WiMAX Identifiers

Device identifier 48-bit Ethernet-like MAC address: 00-1A-45-C2-FE-9D Every WiMAX device is manufactured with a unique MAC address and a X.509

certificate

MAC address can be cryptographically authenticated using PKI (a.k.a.device authentication)

Identifier of MS in the ASN. Subscriber identifier

NAI (RFC 4282): [email protected] Identifier of the subscriber in the CSN.

A subscriber can use multiple devices Exception:

Device identifier can also substitute for subscriber identifier. 1-to-1mapping between Bob and 00-1A-45-C2-FE-9D

BLG609E Network Architecture+WiMAX Revised

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