British Computer Society Presents
Mobile Telecommunication
By Nadine Mouali
Technical PresentationMonday 17 June, 2002
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Mobile TelecomAgenda
1. Overview of Cellular Systems
2. The Handset
3. The SIM Card
4. The Radio Interface and Microwave Transmission
5. The GSM Network
•The Base Station Subsystem
•The Network Subsystem
6. The Value Added Services on GSM
•Voice Mail
•SMS
•Fax and data
7. Coverage and Infrastructure Management
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Mobile TelecomIntroduction
Radio = 170 years old
Sender
Means
Reception
MassMedia
GSM = 20 years old
Telephone = 110 years old
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Mobile TelecomOverview of Cellular Systems
GSM
Group Special Mobile
Global System for Mobile Communication
DCS
Digital Cellular System
PCS
Personal Communications Services
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Mobile TelecomWhat’s a Cell ?
This is a cell
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Mobile TelecomCell Coverage
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Mobile TelecomCell Coverage in Belgium
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Mobile Telecom
Rationalized architecture - Easily maintainable by IT with significant resource savings
Quantum
IMS
SAP
DBGIS
DB
DB
Data
Base
GIS on MapGuideServer
TeleAtlas
Mapmaking
Tool
Web server
GIS clients
via web browser
background
Predicted coverage
Site, links, faults
Shops and Dealers
Geographical Information System for Coverage Management
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Mobile Telecom
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Mobile TelecomThe handset
• Handset is a transmitter and receiver (2 watt)
• Most important is the IMEI
• IMEI = International Mobile Equipment Identity
• This is a unique number
• Is the passport for the handset on the networkYou also need :
• MSISDN number (e.g. 0496/45.85.22)
• IMSI
• SIM
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Mobile TelecomWhat is a SIM Card ?
Credit card model
Plug-in model
SIM = Subscriber Identity Module
It’s the hart of all mobile communicationIt’s your personal passport on the network
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Mobile TelecomWhat is on a SIM Card ?
• SIM Serial• IMSI• Security Files :
• Secret Key (PIN1, PIN2, PUK)Secret Key (PIN1, PIN2, PUK)• Encrypting Key (ki)Encrypting Key (ki)
• User Information ---->
• Configuration Data
• Network Information• Channel Info Channel Info • Preferred NetworkPreferred Network• Location DataLocation Data• Prohibited NetworksProhibited Networks
• ADM = phonebook memory• 100 numbers of 14 digits100 numbers of 14 digits• 12 alphatags12 alphatags
• FDN = fixed phonebook memory• 20 numbers of 14 digits20 numbers of 14 digits• 12 alphatags12 alphatags
• SMS = short messages• 10 messages of 160 characters10 messages of 160 characters
• MSISDN = Mobile Subscription Integrated Service Digital Network
• 4 numbers of 12 digits ( memory help )4 numbers of 12 digits ( memory help )• they are your own mobile numbers ( voice, they are your own mobile numbers ( voice,
data, fax and 2nd line )data, fax and 2nd line )• SMSC = short messages service centre
number• +32486000005+32486000005
• SDN * = Service Dailling Numbers• 10 numbers of 14 digits10 numbers of 14 digits• 12 Alphatags ( fixed on the memory of the 12 Alphatags ( fixed on the memory of the
cardcard )
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Mobile TelecomWhat is a SIM Toolkit ?
• All GSM Services Can be updated or modified by OTA ( Over The Air programming. For this purpose, a SIM toolkit is provided in the Subscriber Identification Module.
• Simtoolkit is an application that is stored on your Simcard and offers you a 2-way communication between the network and the SIM
• It appears as an extra menu in the phone and offers intelligent value added services to the customer
• Examples:• Ordering pizza• Ordering a taxi• Paying your bills• etc...
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Mobile TelecomRadio Transmission
Radio Link
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Mobile Telecom
3 4 5 6 7 0 1 3 4 5 6 7 0 1
7 0 1 3 4 5 6 7 0 1 3 4 5 6 7
MS RX
MS TX
Monitoring
Operation of a mobile station in active speech or data communication using a single time slot.
The TDMA Frame
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Mobile Telecom
uplin
k
• From mobile phone to base station• Frequency 1710 MHz. / 1785 MHz.• Used for transmitting (Tx channel)• 374 up link-channels
The Radio Up Link
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Mobile Telecom
• From the base station to mobile phone• Frequency 1805 MHz / 1880 MHz• Used for receiving (Rx channel)• 374 down link-channels
downlin
k
The Radio Down Link
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Mobile TelecomRadio Transmission
Interfering Factors in Radio Link
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TREES
Radio Interference
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BUILDINGS
Radio Interference
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BUILDINGSInterference through reflection
Radio Interference
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WEATHER
Radio Interference
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Mobile Telecom
paper leadbrick
Radio Transmission Permeability
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Mobile TelecomMicrowave Transmission
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Mobile TelecomMicrowave transmission
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Mobile Telecom
5-10 km
Microwave transmission within a cell
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Mobile Telecom
Better coverage
here
Thanhere
BTS Site
Antennas (the BTS Sites) are on roofs of buildings or at elevated positions. It stands to reason that you will get better coverage, the higher up in the building you are.
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Mobile Telecom
Mobile Station
Base StationSub System
Network Switching Sub System
Public SwitchedTelephone Network
Operating Sub System
Basic Schedule of the GSM Network
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Mobile Telecom
Base StationController (BSC)
Star configuration
BS
BS BS
BS
The Base Station Sub System Configuration
BS
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Mobile Telecom
BSC
Closed loop
BS
BS
BS
BS
Daisy Chain Configuration
The Base Station Sub System Configuration
BS
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Mobile Telecom
Photo of base station high in the sky + microwave (source GIS)
Example of base station (microwave transmitter)
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Mobile Telecom
Motorway
Example of Base Station
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Mobile Telecom
Church
Example of Base Station
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Mobile Telecom
Rooftop ofBuilding
Example of Base Station
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Mobile Telecom
Top of lamppost
Example of Base Station
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Mobile Telecom
Base Station (BTS)
Base Station (BTS)
Base StationController (BSC)
Network Switching Sub System
(NSS)
Manhattan centre
The Functionality of a Base Station Sub System
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Mobile Telecom
BSC
BSC
BSC
BSC
BSC BSC
Base Subsystems and Network Subsystems
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Mobile Telecom
BSC
BSC
BSC
BSC
BSC BSC
MSC
Network Subsystems - The Switch
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Mobile TelecomBase Subsystems and Network Subsystems
Other telephone networks
Exchange
Base station
Base station
Telephone
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Mobile Telecom
Network Switching Sub System
Home LocationRegister (HLR)
Visitor LocationRegister (VLR)
Equipment IdentityRegister (EIR)
AuthenticationCentre
Echo Canceller
BTS
Public Switched Telephone Network
(PSTN)
Mobile SwitchingCenter (MSC)(controls HLR,VLRand EIR)
The Network Switching Sub System
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Mobile Telecom
PSTN
GATEWAYMSC
hlr vlr
Network Switching Sub System(NSS)
BSC
BTS
MSC
MS
A Call From a PSTN Phone to a Mobile Phone
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Mobile Telecom
MSCHLR
Network Switching Sub System (NSS)
VLR
MSC
BSC
RBS
RBS
MS
MS
A Call From Mobile to Mobile
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Mobile TelecomValue Added Services on the GSM network
• Voice Processing System (VPS)
• Short Message Service Centre (SMSC)
• Data and Fax facilities
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Mobile TelecomValue Added Services on the GSM network
Fax and Data Facilities :
• Separate Data and Fax number needed• PCMCIA card• Laptop and communication software
Advantages of FAX and Data on ISDN
• Digital system, does not recognize difference between speech, fax or data
• Standard sends on all 3 a speech signal
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Mobile Telecom
Examples of PCMCIA Cards :
Value Added Services on the GSM network
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Mobile TelecomSummary
1. Overview of Cellular Systems
2. The Handset
3. The SIM Card
4. The Radio Interface and Microwave Transmission
5. The GSM Network
•The Base Station Subsystem
•The Network Subsystem
6. The Value Added Services on GSM
•Voice Mail
•SMS
•Fax and data
7. Coverage and Infrastructure Management