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Aspects of UMTS
Author: Tassilo Bassermann
Outline of report
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Cellular standards
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UMTS Characteristics
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Evolution of wireless communication systems
Features and services of UMTS
UMTS Architecture
Cell Hierarchy
 Network Architecture
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UMTS Technology
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Multiplexing
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Wireless Communication Systems
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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
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Wireless Communication Systems
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Second Generation (2G):
Development driven by need to improve
transmission quality, system capacity and
coverage
 Introduction of digital technologies (early 90´s)
 Services:
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Domination of speech transmission
Demands for fax, SMS, data transmission
Circuit switched networks
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Wireless Communication Systems
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Second Generation (2G):
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2G Technologies
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Wireless Communication Systems
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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)
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New Core Network (routing)
Importance of IP and internet access
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Wireless Communication Systems
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Transition from 2G to 3G (2.5G):
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EDGE (Enhanced Data for Global Evolution)
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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
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Wireless Communication Systems
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Third Generation (3G):
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Requirements:
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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
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Wireless Communication Systems
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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
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Wireless Communication Systems
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IMT – 2000:
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UMTS Characteristics
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UMTS (Universal Mobile Telecommunication
Standard):
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Defined by Third Generation Partnership Project
(3GPP) in 1999
European Version of 3G mobile communication
system
Spectrum allocation (Europe):
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UMTS Characteristics
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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
12
98,81
5
0,561
SUM
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UMTS Characteristics
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UMTS – Services:
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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)
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UMTS Characteristics
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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)
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UMTS Characteristics
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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
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UMTS Architecture
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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
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UMTS Architecture
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UMTS Technology
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UTRAN (UMTS Terrestrial Radio Access
Network):
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Two essential radio interface models
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UTRA-FDD (Frequency Division Duplex)
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UTRA-TDD (Time Division Duplex)
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UMTS Technology
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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
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Tassilo Bassermann
UMTS Technology
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UTRA – TDD:
Unpaired frequency bands
 One single 5 MHz band
 Usage of time slots
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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
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UMTS Technology
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FDD – TDD:
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UMTS Technology
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W-CDMA (Wideband Code Division
Multiple Access):
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Motivation:
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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
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UMTS Technology
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W-CDMA:
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Method to compare two (orthogonal) codes:
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UMTS Technology
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W-CDMA:
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Signal coding:
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Non Return To Zero
Transmission
Signal bit combined with code
pattern (chips)
Every bit is substituted with
the resulting pattern
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Increased data rate
Increased need of bandwidth
Band spreading
UMTS
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UMTS Technology
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W-CDMA:
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Usage of constant chip rate
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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
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UMTS Technology
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Bit rate – spreading factor (FDD):
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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
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UMTS Technology
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Creation of orthogonal codes (channelization
codes, spreading codes):
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UMTS Technology
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Channelization code:
Possibility to change data rate every 10 ms
 Requirement:
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Synchronous coded signals
Downlink synchronous (station to user equipment)
Uplink asynchronous (user equipment to station)
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Additional code required
Scrambling code
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UMTS Technology
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Scrambling Code:
Synchronous and asynchronous orthogonal
codes
 Terminal Separation (uplink)
 Cell Separation (downlink)
 Does not affect bandwidth
 Multiplication with spreaded signal is
transmitted
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Conclusion
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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)
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Sources
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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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Tassilo Bassermann
End of Session
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6. April 2004
Thank you for your attention!
UMTS
Tassilo Bassermann