Aspects of UMTS Author: Tassilo Bassermann. 6. April 2004UMTS Tassilo Bassermann Outline of report...

Aspects of UMTS

Author: Tassilo Bassermann

6. April 2004 UMTSTassilo Bassermann

Outline of report

Cellular standards Evolution of wireless communication systems

UMTS Characteristics Features and services of UMTS

UMTS Architecture Cell Hierarchy Network Architecture

UMTS Technology Multiplexing


Wireless Communication Systems

First Generation (1G): Analog Cellular Transmission of analog voice information Most prominent technology: AMPS (Advanced

Mobile Phone System) In Germany: A- B- and C-Net (1958, 1972,

1985) Immense annual growth rates, rising to nearly

20 million subscribers worldwide by 1990



Second Generation (2G): Development driven by need to improve

transmission quality, system capacity and coverage

Introduction of digital technologies (early 90´s) Services:

Domination of speech transmission Demands for fax, SMS, data transmission

Circuit switched networks



Second Generation (2G): 2G Technologies



Transition from 2G to 3G (2.5G): Intermediate standards to 3G Motivation: Avoiding costs for new

transmission technologies and infrastructure HSCSD (High Speed Circuit Switched Data) GPRS (General Packet Radio Service)

New Core Network (routing) Importance of IP and internet access



Transition from 2G to 3G (2.5G): EDGE (Enhanced Data for Global Evolution)

GSM/GPRS upgrade (TDMA/FDMA) Modulation Enhancement (8-PSK, Phase Shift

Keying) Attractive for operators which cannot afford a

licence for the radio spectrum Possible data rate of 384 kbit/s



Third Generation (3G): Requirements:

High data rates Flexible operating environments Spectral efficiency/capacity Multimedia services Packet data network and IP mobility Global roaming Quality of service Interoperability with 2G networks



Third Generation – IMT-2000: IMT-2000 (International Mobile

Telecommunications at 2000 MHz) A standard created by the ITU (International

Telecommunications Union) Different standards grouped together, to

support existing infrastructure



IMT – 2000:


UMTS Characteristics

UMTS (Universal Mobile Telecommunication Standard): Defined by Third Generation Partnership Project

(3GPP) in 1999 European Version of 3G mobile communication

system Spectrum allocation (Europe):



UMTS – Licenses (Germany):

Operator Paired Packets Bil. DM Unpaired Packets Bil. DM

E-Plus / Hutchinson

2 16,42 1 0,0736

Group 3G 2 16,45 1 0,1227

Mannesmann Mobilfunk

2 16,47 1 0,121

Mobilcom 2 16,37 1 0,121

T-Mobil 2 16,58 1 0,1227

Viag Interkom 2 16,52

SUM 12 98,81 5 0,561



UMTS – Services: Information (online information) Education (virtual school) Entertainment (audio on demand) Community Services (administration transactions) Business Information (mobile office) Communication (video-conference) Business Services (virtual banking) Special Services (online support)



UMTS – Service Classes: Conversational (real-time, voice-video, low

jitter, low delay) Streaming (real-time, multimedia, low jitter) Interactive (limited response time, browsing,

database retrieval, low round trip delay time, low BER)

Background (stable transactions, e-mail, file transfer, low BER)



UMTS Advantages: Improved capacity (4 to 5 times higher

compared with GSM) Variable bit rate Quick and secure connection establishment Breathing cells Improved signal to noise ratio Broadband spectrum Macro diversity


UMTS Architecture

Cell Hierarchy

Cell Range Max. data rate Max. Velocity

Macro cell 2km 144kbit/s 500km/h

Micro cell 1km 384kbit/s 120km/h

Pico cell 60m 2Mbit/s 10km/h


UMTS Architecture


UMTS Technology

UTRAN (UMTS Terrestrial Radio Access Network): Two essential radio interface models

UTRA-FDD (Frequency Division Duplex)

UTRA-TDD (Time Division Duplex)


UMTS Technology

UTRA – FDD: Paired frequency bands Two 5 MHz bands, for uplink and downlink Duplex distance of 190 MHz Signal spreading (Channelization code) W-CDMA Transfer rate of 3.84 million symbols per

second (Mcps) Primary technology for UMTS in Europe


UMTS Technology

UTRA – TDD: Unpaired frequency bands One single 5 MHz band Usage of time slots

Configuration of symmetric services Configuration of asymmetric services Advantage for data transmissions

One frame (10 ms) consists of 15 timeslots Signal spreading (Channelization code) W-CDMA combined with TDMA


UMTS Technology

FDD – TDD:


UMTS Technology

W-CDMA (Wideband Code Division Multiple Access): Motivation:

Use of Code-Multiplexing to transfer different signals over the same carrier

Separation through different code patterns Receiver uses an orthogonal code, to demultiplex

the specific signal


UMTS Technology

W-CDMA: Method to compare two (orthogonal) codes:


UMTS Technology

W-CDMA: Signal coding:

Non Return To Zero Transmission

Signal bit combined with code pattern (chips)

Every bit is substituted with the resulting pattern

Increased data rate Increased need of bandwidth Band spreading


UMTS Technology

W-CDMA: Usage of constant chip rate

7,68 Mcps = bit rate * spreading factor (downlink) 3,34 Mcps = bit rate * spreading factor (uplink)

FDD spreading factor (4, 8, 16, 32, 64, 128, 256, 512(DL))

TDD spreading factor (1,2,4,8,16) Possibility to increase signal power of user equipment,

through reduction of the bit rate


UMTS Technology

Bit rate – spreading factor (FDD):

Bit rate Uplink Downlink

15kbit/s 256 512

30kbit/s 128 256

60kbit/s 64 128

120kbit/s 32 64

240kbit/s 16 32

480kbit/s 8 16

960kbit/s 4 8

1920kbit/s Not possible 4


UMTS Technology

Creation of orthogonal codes (channelization codes, spreading codes):


UMTS Technology

Channelization code: Possibility to change data rate every 10 ms Requirement:

Synchronous coded signals Downlink synchronous (station to user equipment) Uplink asynchronous (user equipment to station)

Additional code required Scrambling code


UMTS Technology

Scrambling Code: Synchronous and asynchronous orthogonal

codes Terminal Separation (uplink) Cell Separation (downlink) Does not affect bandwidth Multiplication with spreaded signal is

transmitted


Conclusion

UMTS offers several advantages for operators and users compared with GSM

Necessary net coverage achieved (25% of population, Germany)

No experience with new technologies / risks Expensive user equipment Attractive competitors (GPRS, EDGE) Cautious operators after immense licence costs UMTS (FOMA) success in Japan (NTT

DoCoMo)


Sources

Riemer, Rudolf. UMTS – A Technical Overview. 2004. 6 April 2004 <http://www.umtslink.at/>.

UMTS. 4 Feb 2004. International Engineering Consortium. 6 April 2004 <http://www.iec.org/tutorials/umts>.

UMTS Resources. 8 Feb 2004. 6 April 2004 <http://www.3gnewsroom.com/html/whitepapers/>.

3G Wireless Standards. March 2004. Siemens mobile. 6 April 2004 <http://www.siemens-mobile.com/>.

Thomas, Andrew. 3G-Technology Specification. 2004. 6 April 2004 <http://www.three-g.net/>.


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Aspects of UMTS Author: Tassilo Bassermann. 6. April 2004UMTS Tassilo Bassermann Outline of report...

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