A Comparative Study Between Next Generation UMTS · PDF fileA Comparative Study Between Next Generation UMTS and WiMAX Systems 7/36. The WiMAX Physical Layer OFDMA ((p )OFDM ... WCDMA

A Comparative Study Between Next yGeneration UMTS and WiMAX

Systemsy

10 07 200810.07.2008

Student: Noureddine OuertaniSupervisors:

P f D t h Ad l J kProf. Dr. techn. Admela JukanSaid Zaghloul

Outline

Motivation Comparaison of the Physical Layer Comparaison of the Overall Architecture Comparaison of the Overall Architecture Comparaison of the QoS Management

C l i Conclusion

A Comparative Study Between Next Generation UMTS and WiMAX Systems 2/36

Motivation

What is WiMAX ?

• Worldwide Interoperability for Microwave Access.• Operates in the 10 to 66 GHz and the 2 to 11 GHz(IEEE 802.16)

What is WiMAX ?

pfrequency ranges.• Promises data transfer rates: up to 108 Mbit/s.

Source: www.wimax-forum.com

Wh t i UMTS ?• Universal Mobile Telecommunication System.• Operates in the following frequency ranges:

What is UMTS ?

• HSDPA : High Speed Downlink Packet Access1920 MHz – 1980 MHz (Uplink)2110 MHz – 2170 MHz (Downlink)

• Promises data transfer rates:t 14 4 Mbit/ ith HSDPA

• HSDPA : High Speed Downlink Packet Access.

• HSUPA : High Speed Uplink Packet Access.up to14.4 Mbit/s with HSDPAup to 5.8 Mbit/s with HSUPA


Source: www.umts-store.net

Evolution

(IEEE 802.16)Source: www.wimax-forum.com


Source: www.umts-store.net

PART ONEComparaison of the Physical Layerp y y

WiMAX Physical Layer

UMTS Physical Layer

- Some selected aspects -


The WiMAX Physical Layer Transmission Technique : OFDMq

•Divide the existing bandwidth W into N = W/∆f orthogonal•Divide the existing bandwidth W into N = W/∆f orthogonal frequencies (channels), the so called OFDM-subcarriers or subcarriers.

•Simultaneous transmission of these N narrow-band orthogonal frequencies instead of a single carrier transmission.

ampit deampitude

∆fFrequency spectrum of a single carrierFrequency spectrum of N orthogonal subcarriers

ffrequency

W Source: ”WiMAX”, Nuaymi (modified)A Comparative Study Between Next Generation UMTS and WiMAX Systems 6/36

The WiMAX Physical Layer Realisation of OFDM

• Matrix computation : Application of an IFFT operator (Inverse Fast• Matrix computation : Application of an IFFT operator (Inverse Fast Fourrier Transform Operator) on N modulation symbols possibly different modulated : BPSK, QPSK, QAM-16, QAM-64

•Result : OFDM-signal,where each (modulation) symbol is transmitted on one of the orthogonal subcarriers (frequencies).

serial/parallel

X(0) ... X(N -1) X(0)

IFFTconversion

X(N -1)OFDM

signal

T

TSource: ”WiMAX”, Nuaymi (modified)


The WiMAX Physical Layer OFDMA (OFDM Multiple Access)( p )

Idea:Idea:

• OFDM-design intented for a single user (signal) transmission.

• Association of a multiple access technique like TDMA or FDMA to OFDM toAssociation of a multiple access technique like TDMA or FDMA to OFDM to get multiuser transmissions.

Principle: p

• Division of OFDM subcarriers into sets of subcarriers, the so calledsubchannels.

• Subcarriers composing a subchannel must not be adjacent.

→ New dimension→ New dimension.


The WiMAX Physical Layer OFDMA (OFDM Multiple Access)( p )

D t b iData subcarriers

Right guardLeft guard Right guard

subcarriers

Left guard

subcarriers

Subchannel 1 Subchannel 2 Subchannel 3 Subchannel 4 DC

DC : direct current Null carrier (no transmission)Source: ”WiMAX”,Nuaymi (modified and siplified)


Illustration of the OFDMA Multiple Accessp

A time and a subchannel allocation for each communication process of aA time and a subchannel allocation for each communication process of a downlink and an uplink user, respectively.

Subchannels User 1

User 2

User 3

User 4

User 5

Source: ”WiMAX”,Nuaymi (modified)

TimeOFDM OFDMOFDM OFDMSymbol n Symbol n+1 Symbol n+2 Symbol n+3


The WiMAX Physical LayerLink Adaptionp

• Radio link OK → Use a high-level modulation (exp: 64-QAM)Radio link OK → Use a high level modulation (exp: 64 QAM)

• Radio link bad → Use a low-level but robust modulation (exp: QPSK)

Source: www.csie.ndhu.edu.tw/~robert/Wimax/WiMax-

Architecture pdfArchitecture.pdf


The UMTS Physical Layer Transmission Technique : CDMAq

• All users send at the same time and with the same frequency. code

• Separation of users via codes

•Application of spread spectrum t h itechnique.

• Transmit bit sequence is multiplied by a connection- frequencyp yspecific code signal and thus spread in the frequency range.

timetimeSource: script „fundamentals of radio communications“ Prof.Dr.-Ing.T Kürner


Illustration of the CDMA Transmission Process

Data signal d(t)+1

Time tBit time

g ( )+1

1-1

+1Code signal c(t)

-1Spread signal c(t).d(t)

Time t

+1p g ( ) ( )

Ti t

(+1).c(t) (+1).c(t)(+1).c(t)(-1).c(t)

Source: Lüders, “ Mobilfunksysteme“ (modified)-1

Time t

A Comparative Study Between Next Generation UMTS and WiMAX Systems 13 /36

CDMA uses orthogonal codes of variable lengthg

Exp : Walsh-Hadamard codes SF =16Exp : Walsh-Hadamard codes

SF =2SF =4

SF 16SF =8

SF =1

Bit time: TBit time: T

Chip time: T

Spread factor: SF = T / Tbi

bit

chip

chipbitT

Source: script „fundamentals of radio communications“ Prof.Dr.-Ing.T Kürner

Spread factor: SF = T / Tbit chipchipT


WCDMA (Wideband CDMA)( )

The sent signal is strongly spread. → Higher bandwidth.The sent signal is strongly spread. Higher bandwidth.

fdP/dfdP/df

ffN b d i l B d b d i l

PowerS d i l

Interference

Narrow band signal Broad band signalSource: „mobile communications“ Jochen Schiller

Spread signal→ Robustness against narrow band interference impulses.


Source: script „mobile communications“ Prof.Dr.-Ing.L Wolf f

HSDPA / HSUPA

UMTS rel 5 introduced a high speed downlink packet access (HSDPA) UMTS rel-5 introduced a high speed downlink packet access (HSDPA) with speeds (data rates) in the order of 8 - 10 Mbit/s

Current HSDPA deployments support down-link speeds of 1.8, 3.6, 7.2 and 14 4 Mbit/s14.4 Mbit/s → useful for asymmetrical services that require the largest part of their

capacity in the Downlink. Downlink__ Downlink

__ Uplink

• HSDPA uses Adaptive modulation(QPSK,16-QAM )

HSDPAHSDPASource: script „fundamentals of radio communications“ Prof.Dr.-Ing.T Kürner


HSDPA / HSUPA

Downlink UMTS rel-6 introduced a high speed

uplink packet access (HSUPA) with speeds up to 5.8 Mbit/s→ useful for asymmetrical services

__ Downlink

__ Uplink

→ useful for asymmetrical services that require the largest part of their capacity in the Uplink.

HSUPA Symmetrical services that require

high data rates on both downlink- and uplink-connections can use both

HSUPA__ Downlink

__ Uplinkuplink-connections can use both HSDPA and HSUPA.

HSUPA and HSUPASource of the figures: script „fundamentals of radio communications“ Prof.Dr.-Ing.T Kürner


Summary of PART ONEy

Transmission technique

WiMAX Physical Layer OFDMAy y

UMTS Physical Layer WCDMAy y


PART TWOComparaison of the Overall Architecturep

The WiMAX Overall Architecture

The UMTS Overall Architecture



WiMAX Architecture Is Standardized…Why?

MobilePedestrian Mobility

y

Fixed Outdoor Mobile Data

Pedestrian Mobility

Fixed indoor

Fixed OutdoorWiMAX-

outdoor antenna

BackhaulBSC

Mobile sers

Base stationEnterprise/campus

BSC : Base Station Controller

Fixed users Mobile usersSource: www.csie.ndhu.edu.tw/~robert/Wimax/WiMax-Architecture.pdf (modified)

Nomadic users


The WiMAX Overall Architecture:The Network Reference Model

NSP

NAP

NSP

ASP Network or I t t

ASN

CSN

Mobile

t ti

ASNInternet

station

NAP : Network Access ProviderASN: Access Service NetworkCSN C ti it S i N t kNAP : Network Access Provider

NSP : Network Service ProviderCSN: Connectivity Service NetworkASP : Application Service Provider

A Comparative Study Between Next Generation UMTS and WiMAX Systems 21/36For more info see: WiMAX-Forum paper [1]

The WiMAX Overall Architecture:The Network Access Provider (NAP)( )

ASN 1 :Profile AASN GWR1 R6

ASN 1 :Profile A

BSR4R3

R4

R1 R6BS

R4

R1 R6Black-box (1 or more black b ) N i t ASN R3

ASN GWR1 R6ASN 2 :Profile A

ASN: Access Service NetworkASN GW: ASN gatewayR1 R6: Reference points

R8

ASN 2 :Profile CASN 2 Profile B

boxes) No intra ASN interoperability possible

R4

ASN 2 :Profile A R1…R6: Reference pointsBS: WiMAX base station

ASN 2 :Profile CASN 2 :Profile B


The UMTS Overall Architecture Is Classified In Domains.

Mobile Equipment CA

+

EquipmentSource: www.dcinside.com

Core

Network

Access

Network

Source: www.itwissen.info

DomainDomain

UMTS Subscriber Identity Module

User Equipment Domain Infrastructure Domain


The UMTS Overall Architecture :The Access Network Domain

RNC RNCBSCBSC

Node B Node BBTS BTSBTS : BaseRNS : Radio Network System

Base Station Subsystem

BTS : Base Transceiving Station

RNC:Radio Network Controller

UTRAN :UMTS terrestrial radio access network

GSM Radio Access NetworkBSC :Base Station Controller RNC:Radio Network Controller

RAN : Radio Access NetworkA Comparative Study Between Next Generation UMTS and WiMAX Systems 24/36


Mobile Equipment CA

+

EquipmentSource: www.dcinside.com

Core

Network

Access

Network


DomainDomain




The UMTS Overall Architecture :The Core Network Domain (rel-5) ( )

UMTS rel-5 specifies a radically different core network The GSM/GPRS basedMSC: Mobile Switching Center SGSN: Serving GPRS Support NodeHSS H S b ib SPSDN: Public Switched Data Network PDN: Public Data NetworkUMTS rel 5 specifies a radically different core network.The GSM/GPRS based network (UMTS rel-4) will be replaced by an almost all-IP-core

MSC: Mobile Switching Center SGSN: Serving GPRS Support Node

VLR: Visitor Location Register GGSN: Gateway GPRS Support Node

GMSC: Gateway MSC Application ServerInternet

HSS: Home Subscriber ServerEIR: Equipment Identity Register

PSDN: Public Switched Data Network PDN: Public Data Network

GMSC: Gateway MSC IMS: IP Multimedia Subsystem PDNPSDNCircuit Switched (CS)

Packet Switched (PS) HSS

GGSNGMSC( )Domain

( )DomainCore

Network EIRMSC/VLR SGSN


RAN BSCBSC

Summary of PART TWOy

WiMAX Overall Architecture UMTS Overall ArchitectureThe Network Reference Model The UMTS Domains

1 The User Equipment Domain1. The Mobile Station2. The Network Access Provider3 Th N t k S i P id

1. The User Equipment Domain 2. The infrastructure Domain2.1.The Access Network Domain2 2 Th C N t k D i3. The Network Service Provider

Three ASN profiles

2.2. The Core Network Domain

Radio Access Network RANp1. GSM RAN2. UTRAN


UMTS rel-5 :almost all-IP-core

PART THREEComparaison Of The QoS Managementp Q g

The QoS Classes of WiMAX and UMTS

A WiMAX QoS Management Scenario



The QoS Classes of WiMAX and UMTSQ

Corresponding Example of supportedQoS Class of UMTSCorrespondingQoS Class of WiMAX

Example of supported service

Background Best Effort (BE) data transfer ( Email)

Interactive Non-real-time Polling Service (nrtPS)

interactive services(online video games… )( )

Streaming Real-time Polling Service (rtPS)

video transmission video-on-demand, internet-radio

Conversational Extended Real-time Polling Service (ertPS)

direct communication like telephony and video telephony.

Unsolicited Grant VoIP with activity detection


Unsolicited Grant Service (UGS)

y

A WiMAX QoS Management ScenarioQ g

user1 user2WiMAX BS 1

WiMAX- core network

What happens in the base station and the mobile station ?

V IP ith t il i

WiMAX-BS 2WiMAX-BS 1

VoIP without silence suppression

Video transmissionTFTP CS- CPS

HTTPEmail

SAP SAP

MACMAC -CPSMAC - CS


Summary of PART THREEy

• Both WiMAX and UMTS define QoS classes to differenciate services.

• Services are mapped into QoS Classes.


Summaryy

WiMAX UMTS

Physical layer OFDM WCDMA

Defined through the Network Reference Model

Divided into Domains

Two Radio AccessOverall Architecture

Network Reference Model

Th ASN fil

Two Radio Access Networks

Three ASN profiles Almost all-IP-core with release 5

QoS


QoS Management Through mapping of services into QoS Classes.

Conclusion

3G(W CDMA)3G(W-CDMA)

WiMAX

The figure (left) shows a test Mobile-WiMAX base station co-locating at existing 3G base site.

Both technologies WiMAX and UMTS are beeing developed and are evoluating at the same time (remember Motivation).( )

•So, which technology is going to convince and

WiMAXWiMAX

gain more users ?

• Which technology is going to establish itself as standard in the few next years ?

Source: www.softbank.co.jp

standard in the few next years ?


References

Books:Books:1. “WiMAX”,Nuaymi Loutfi2. “HSDPA/HSUPA for UMTS: High Speed Radio Access for Mobile

Communications”, Holma and Toskala.3. “ Mobilfunksysteme“,Lüders IEEE papers :1. “A Survey on Mobile WiMAX”

“N t k A hit t f 4G C t C id ti ”2. “Network Architecture for 4G: Cost Considerations”3. “Extending 3G/WiMAX Networks and Services through Residential

Access Capacity”4 “High-Speed Packet Access Evolution in 3GPP Release 7”4. High-Speed Packet Access Evolution in 3GPP Release 7

3GPP papers :1 “Service Requirements for the All-IP Network (AIPN)” stage1 (rel8)1. Service Requirements for the All IP Network (AIPN) stage1 (rel8)2. “Architecture enhancements for non-3GPP accesses” (rel8)


References

WiMAX-Forum papers :WiMAX Forum papers :1. “A technical overview and performance evaluation”, march 2006Websites:1. www.wimaxforum.org/technology/downloads/g gy2. www.tech-invite.com/Ti-ims-releases.html#fig53. www.tik.ee.ethz.ch/~mobydick/related_work/umts/p36-

45_allIP_UMTS.pdf3 i tf / di /05 / lid /16 4 df4. www3.ietf.org/proceedings/05nov/slides/16ng-4.pdf

5. www.csie.ndhu.edu.tw/~robert/Wimax/WiMax-Architecture.pdf6. www.hsdpa.com7 it issen info7. www.itwissen.info8. www.dcinside.comScripts:1 “ Fundamentals of radio communications“ Prof Dr Ing T Kürner1. Fundamentals of radio communications , Prof.Dr.-Ing.T Kürner2. “ Mobile communications “, Prof.Dr.-Ing. L Wolf


Thank you for your attention !y y


Backup Slidesp

Th WiMAX h i l l / T i i t h i OFDM1. The WiMAX physical layer / Transmission technique : OFDM2. Scalable OFDMA3. Sublayers of the WiMAX-MAC layer4 The WiMAX Mobile Station4. The WiMAX Mobile Station5. The WiMAX Network Reference Model6. WiMAX uses Sliding Window ARQ Mechanism 7 WiMAX-MAC uses Hybrid-ARQ7. WiMAX-MAC uses Hybrid-ARQ8. WCDMA (Wideband CDMA)9. WiMAX Architecture Is Standardized.10 The UMTS Overall Architecture Is Classified In Domains10. The UMTS Overall Architecture Is Classified In Domains.11. The UMTS overall-architecture :The Core Network Domain (rel-5)12. The QoS classes of WiMAX13. QoS Management Scenario (WiMAX)Q g ( )14. The QoS classes of UMTS

A Comparative Study Between Next Generation UMTS and WiMAX Systems Backup 1/16

The WiMAX physical layer Transmission technique : OFDMq

OFDM-subcarriers orthogonal to each otherOFDM-subcarriers orthogonal to each other

→ Elimination of interference between the channels.

Possibility of different digital modulation for each subcarrier (BPSK• Possibility of different digital modulation for each subcarrier (BPSK, QPSK, QAM-16, QAM-64)

• Reduced frequency bandwidth ↔ Longer time periods• Reduced frequency bandwidth ↔ Longer time periods

• Data symbol duration N times longer as in the single carrier transmissiontransmission.

→ Better multipath resistance with regard to a single carrier.

→ Higher system robustness→ Higher system robustness.


Scalable OFDMA (SOFDMA)( )


Sublayers of the WiMAX-MAC layerSublayers of the WiMAX-MAC layery yy y

CS-SAPService-specific

convergence sublayer (CS)

MAC-SAPMAC common part

convergence sublayer (CS)MAC-

layersublayer (MAC CPS)

Security sublayer

PHY-SAPPhysical layer

(PHY)

PHY-

layer (PHY)layer

source: A paper of the IEEE communications magazine dec 2007 with the title: „A survey on mobile WiMAX“ (modified)A Comparative Study Between Next Generation UMTS and WiMAX Systems Backup 4/16

The Mobile Station


The WiMAX Network Reference Model


The WiMAX Overall Architecture:The Network Reference Model

Visited NSP NAP

CSN ASP network or Internet ASN

Mobile

t ti

ASN

station

Home NSPNAP : Network Access ProviderASN: Access Service NetworkCSN C ti it S i N t k

ASP network or Internet

CSN

Home NSPNAP : Network Access Provider

NSP : Network Service ProviderCSN: Connectivity Service NetworkASP : Application Service Provider

A Comparative Study Between Next Generation UMTS and WiMAX Systems 7/18For more info see: WiMAX-Forum paper [1]

WiMAX uses Sliding Window ARQ Mechanism


WiMAX-MAC uses Hybrid-ARQy Q


WCDMA (Wideband CDMA)( )

The sent signal is strongly spread.The sent signal is strongly spread.

→ Higher bandwidth.

→ Robustness against narrow-band interference impulses.

Some technical features of UMTS-WCDMA :

Radio channels are 5 MHz wide.

Chip rate of 3.84 Mcps.

Supports 2 basic modes of duplex: frequency division and time divisiondivision.


WiMAX Architecture Is Standardized.

• Creation of the network specification.

• Definition of the network requirements and priorities.

Source: www.wimax.com



Mobile Equipment

Home

Network

+

EquipmentServing

Network

Source: www.dcinside.com Access

Network

Domain

T itNetwork

DomainSource: www.itwissen.info

Network

DomainTransit

Network


Core Network Domain

Domain



The UMTS Overall Architecture is Classified In Domains.

Mobile Equipment

Home

Network

+

EquipmentSource: www.dcinside.com Access

Network

DomainServing

Network T it


Network

Domain

Network

DomainTransit

Network


Core Network Domain

Domain



The UMTS overall-architecture :The Core Network Domain (rel-5)( )

�Source : http://www.tech-invite.com/Ti-ims-releases.html#fig5


The UMTS overall-architecture :The Core Network Domain (rel-5)( )

�Source : http://www.tech-�i i /Ti i l�invite.com/Ti-ims-releases�.html#fig5


The QoS classes of WiMAXQ

1 Unsolicited Grant Service (UGS) :1. Unsolicited Grant Service (UGS) :- real-time data stream fixed-size data packets issued periodically.- Exp: Voice over IP without silence suppression.

2 Real-time Polling Service (rtPS):2. Real-time Polling Service (rtPS):- real-time data streams with variable size that are issued periodically. - Exp: MPEG (Moving Pictures Experts Group) video transmission.

3 Non-real-time Polling Service (nrtPS):3. Non-real-time Polling Service (nrtPS):- delay-tolerant data streams that are composed of variable-size data packets for which a minimum data rate is compulsory.- Exp: FTP transmission.p

4. Best Effort (BE):- data without minimum service guarantees. Exp: Email

5. Extended Real-time Polling Service (ertPS):5. Extended Real time Polling Service (ertPS):- combination of UGS and rtPS-class variable rate real-time applications having rate and delay requirements. Exp: VoIP with activity detection.


QoS Management Scenario (WiMAX)Q g ( )

CS-SAPService-specific

convergence sublayer (CS)

The figure shows the sublayers of the WiMAX-MAC layer .

MAC-SAPMAC common part

convergence sublayer (CS)MAC-

layerWhere does the QoS management happen?

sublayer (MAC CPS)

Security sublayerHere !

PHY-SAPPhysical layer

(PHY)

PHY-

layerMAC: Medium Access Control


(PHY)layer

source: A paper of the IEEE communications magazine dec 2007 with the title: „A survey on mobile WiMAX“ (modified)

SAP: Service Access Point

The QoS classes of UMTS

1 Background: QoS-Class for data transfer ( Email)

Q

1. Background: QoS-Class for data transfer ( Email)- requires the lowest error rate possible.- non-critical restrictions (demands) on bandwidth, delay and jitter.2. Interactive : QoS-Class for the use of interactive services ( web-browsing, ( g

online video games… )- requires the lowest error rate possible.- higher demands concerning delays.3 Streaming: QoS Class for sharing services ( video on demand internet3. Streaming: QoS-Class for sharing services ( video-on-demand, internet-

radio…)- a minimum bandwidth is required.- jitter is allowed within certain limits.

Bit t iti l- Bit errors are not critical.4. Conversational: QoS-Class for direct communication like telephony

and video telephony.- similar requirements to the requirements of the streaming-class.s a equ e e ts to t e equ e e ts o t e st ea g c ass- but jitter and delay must also be small.


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A Comparative Study Between Next Generation UMTS · PDF fileA Comparative Study Between Next Generation UMTS and WiMAX Systems 7/36. The WiMAX Physical Layer OFDMA ((p )OFDM ... WCDMA