systra training programme
DESCRIPTION
Introduction to GSM Digital Communications Traffic Management Signalling Transmission Network Planning & Optimization Nokia ImplementationTRANSCRIPT
SYSTRATraining
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INTRODUCTION
&
EXPECTATIONS
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TRAINING TIMING
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09:30 To 11:00 – Training
11:00 To 11:15 – Break
11:15 To 13:00 – Training
13:00 To 14:00 – Lunch Break
14:00 To 15:30 – Training
15:30 To 15:45 – Break
15:45 To 17:00 - Training
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Contents
Introduction to GSM Digital Communications Traffic Management Signalling Transmission Network Planning & Optimization Nokia Implementation Next Step
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Introduction to GSM
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Module ObjectivesAt the end of this module, you are able to:
• Fundamentals of Cellular Systems
• GSM evolution
• Advantages of GSM over analogue networks
• Interfaces of GSM networks
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Basic concept - 1GSM vs. fixed network Telephony
Local Exchange
MobileSwitchingCentre
fixed medium
Mobile Station
fixed location
Variable Location
Diffuse Medium
Telephone
SONOFON
M N
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Telephony Communication is a basic need in today’s world. Telephone has become part of life.
Fixed Line Telephony
Shortcomings
No Mobility
Long wait for new connections
Security problems.
Prone to Failures(Line disconnection etc)
Very little in the name of value added services
Telephone
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Wireless Communications ModelDisplay
Acoustic coupler
Satellite dish Reciever
Transmitter
Source
Media of transmission is Radio Media of transmission is Radio FrequencyFrequency
Display
Reciever
Transmitter
Source
IBM PS/2
ASCII Printer
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Types Of Wireless Communications
SimplexThe direction of transmission is in one direction only.e.g. Broadcast services?(AM/FM Radios,Television)Paging Services
In this type of communication there is a transmitter which transmits RF carrier ( modulated with information signal), this is received by the receiver which demodulates the information.
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•Half Duplex The direction of transmission is alternate in both directions, e.g. Trunked Radios.
Direction of transmission is in both directions but it is not simultaneous, it is alternate.
Both the ends will have transmitter plus receiver so that at a time if one end transmits the other end will receive only and vice versa.
Push to talk radios are commonly used by police and military.
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Duplex
The direction of transmission is simultaneous in both directions, e.g. Cordless Telephones, Mobile Phones, Microwave Radios.
In Duplex transmission both the terminals will transmit and receive simultaneously. This is the requirement in today’s world requiring advanced wireless mobile applications.
Definitely simultaneous communication is not possible on the same channel.
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Wireless Communications BandsWireless Communications Bands
MF : 300KHz-3MHz(AM Radio)
HF : 3 MHz-30MHz
VHF : 30MHz-300MHz(FM Radio,
Paging services)
UHF : 300MHz-3GHz(Mobile Radios, Cordless
Phones)
SHF : 3GHz-30GHz(Microwave Band)
Selection of Band depends upon Application
Frequency Band is subdivided into Application Bands
Application Band is further divided into Technology Channels
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GSM History19811981 analogue cellular introduced
Franco-German study of digital pan-european cellular system
19821982 Groupe Spécial Mobile (GSM) formed within CEPT
19861986 Permanent group to create standards for a digital system
19871987 MoU signed by over 18 countries
19891989 GSM was moved into the ETSI organisation
GSM name changed to Global System for Mobile communications.
The committees working on the system changed from GSM to SMG
19901990 DCS1800 (edited GSM900) specification developed
19921992 Australia was the first non-European country to join the MoU
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GSM History Continued….
19941994 First GSM Network was launched in South Africa
By December 1994 there were 69 GSM networks in operation
19981998 HSCSD (High Speed Circuit Switched Data) trials in Singapore
19991999 First mobile data call using GPRS in a live network was made
20012001 MMS (Multimedia Messaging Service) has been standardized
20032003 UMTS Network operators in Europe..
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GSM Evolutionary Steps
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Scenarios across GSM in the World
USA: PCS1900
UK: GSM900DCS1800
Thailand: DCS1800
Canada:PCS 1900
Argentina,Brazil,Chile:DCS 1800 Malaysia:
DCS 1800
CIS, Denmark, Finland,France, Germany,Greece, Hungary,Poland, Norway, Sweden, Switzerland: GSM900DCS 1800
Singapore: DCS1800
Hong Kong:PCS 1900
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StandardisationETSI
European Telecommunications Standards Institute• Financed by EU
• Co-operation of suppliers and operators
• Specification of European telecommunications standards
ETSI- standards :• Cellular GSM 900/1800 - GPRS - UMTS
• Cordless DECT
• Paging ERMES
• Trunked radio TETRA
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GSM Standards
The GSM Standard is divided into phases (phase 1, phase 2 and phase 2+) all the phases has been finalized by ETSI.
Many of the GSM networks in operation today are currently using the phase 2+. However many of the GSM network operators are starting to implement UMTS (3G support).
The ETSI GSM standard specification is around 5500 pages, and are divided into12 series.
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GSM Status
Specification start-up: 1980
First network in operation: Jan. 1992 (Radiolinja, Finland)
Forecast in 1995:
• At the ITU's Telecom '95 event, were stated that we will reach 100 million subscribers Worldwide before the year 2000.
September 1997: ~55 million subscribers.~1 new subscriber each second.~250 networks in 110 countries.
July 1998:
• More than15 months early then year 2000 the magic figure of 100 million subscribers was reached.
Today : Over 200 million subscribers. 369 networks in 137 countries.
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NMS
NSSBSS
GSM Architecture & Interfaces
BSCHLR/AC/EIR
TCSM
MSC/VLR
BTS
AbisInterface
AterInterface
AInterface
AirInterface
TC
Ater’Interface
O&M Interface
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GSM Architecture & Interfaces
BSC
HLR/AC/EIRTCSM
MSC/VLR
BTS
AbisInterface
AterInterface
AInterface
AirInterface
TC
Ater’Interface
Air interface OPEN• 13 kb/s traffic channels• 8 channels / TRX• some channels reserved for signalling• blocking
Ater interface PROPRIETARY• 16 kb/s traffic channels• up to 120 traffic channels / 2M frame• 64 kb/s CCS#7 signalling• 64 kb/s channels for X.25 NMS connection• blocking
Abis interface PROPRIETARY• 13 kb/s traffic channels• up to 96 traffic channels / 2M frame• one TRXSIG signalling channel / TRX• one BCFSIG signalling channel / BTS• 16, 32 or 64 kb/s signalling rates
A interface OPEN• 64 kb/s traffic channels• 30 traffic channels / 2M frame• 64 kb/s CCS#7 signalling• 64 kb/s channels for X.25 NMS connection
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Interfaces in GSM
Um : MS - BTS (air or radio interface)A : MSC – BSCAbis : BSC – BTS (proprietary interface)Ater : BSC – TRAU (sometimes called Asub)
(proprietary interface)B : MSC – VLRC : MSC – HLRD : HLR – VLRE : MSC – MSCF : MSC – EIRG : VLR - VLR.
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Advantages of GSM
•GSM uses radio frequencies efficiently, and due to the digital radio path, the system tolerates more intercell disturbances.
•The average speech quality is better than in analogue systems.
•Data transmission is supported throughout the GSM system.
•Speech is encrypted and subscriber information security is guaranteed.
•With ISDN compatibility, new services are offered.
•International roaming is technically possible within all countries using the GSM system.
•The large market increases competition and lowers the prices both for investments and usage.
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GSM Specifications
One reason for the major success of GSM is, that it is very accurately standardised. The standard is open, i.e. it is available to everyone. The European Standards Telecommunications Institute (ETSI) is responsible for the GSM standards. The GSM technical specifications are grouped in this way:
01 General Description of a GSM PLMN02 Services03 Network Functions04 MS - BSS Interface05 Radio Path06 Speech Processing Functions07 Terminal Adaptation Functions08 BSS - MSC Interface09 Network Inter Working10 Service Inter Working
11 Type Approval Procedures12 Operation and Maintenance
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Basic Idea of Digital Communication
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Transmission Techniques
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Transmission media
Transmission techniques
Transmission methods
Fibre
Coaxial cable
Copper cable
Microwave radioTerrestrial/satellite
PDH SDH
PCMISDN ATM
HDSL
CATV
Transmission Techniques
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Transmission TechniquesMultiplexing
ITU- Standard:• 8000 samples per sec @ 8bit = 64 kbit/s
• 32 * 64 kbit/s = “2 Mbit/s” line
Lines can be de-/ multiplexed into lines of higher data rates• 8Mbit/s, 34 Mbit/s, 140Mbit/s etc...
....
32 * 64 kbit/s
MUX
2 Mbit/s MUX/deMUX
1 sec1 sec
8 Mbit/s2 Mbit/sMUX/
deMUX
1 sec
....
32 * 64 kbit/s
MUX
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Transmission TechniquesPDH
PDH (Plesiochronous Digital Hierarchy)• Voice spectrum ~ 4kHz
• Sampling rate 8 kHz
• 8 bits per sample
• Divided into 32 TS (TDM)USA : 24 timeslots
Higher Order PDH Bitrates
Europe : 2.048 Mb/sUSA : 1.554 Mb/s
M
U
XM
U
X
140 M
34 M
34 M
34 M
34 M
8 M8 M
8 M
8 MM
U
X
2 M
2 M
2 M
2 M
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SDH (Synchronous Digital Hierarchy)• All network elements are synchronized to Primary Rate
Clock (PRC)
• Worldwide standard : interfacing to USA possible
Europe USA• STM- 1c (51.7 Mb/s) = STS-1
• STM- 1 (155.52 Mb/s) = STS-3
• STM- 4 (622.08 Mb/s) = STS-12
• STM-16(2488.32 Mb/s) = STS-48
• STM-64(9953.28 Mb/s) = STS-192STM-4
STM-1STM-1STM-1STM-1
Transmission TechniquesSDH
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Leased Lines
Transmission lines rented from a “3rd party” operator
Leased line provider is usually also a competitor
Contra• High operating costs• Unpredictable lead times
(installation)• Difficult to deploy (may
include digging, groundwork..)
• No control over the physical route or the quality of the link
Pro• No implementation
effort for buyer• No extra
infrastructure to buy• Long distances are
uncritical
Analyse cost structure of Leased Line tariffs to decide
whether LL or microwave links are more economical
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GENERAL RULE for TS allocation0 : Synchronization1 - 24 : TCH25 - 30 : TRX/BCF SIG31 : Loop control
Max 12 TRX per 2 Mbit frame
AbisInterface
AirInterface
BSCMSC
AInterface
Ater’Interface
TC SM
AterInterface
BTS2
BTS1
bits 1 2 3 4 5 6 7 8TS
0 Synchronisation1 BTS 12 TRX 13 BTS 14 TRX 25 BTS 16 TRX 37 BTS 28 TRX 19 BTS 210 TRX 211 BTS 212 TRX 313 BTS 314 TRX 115 BTS 316 TRX 217 BTS 318 TRX 319 BTS 320 TRX 421 BTS 322 TRX 523 BTS 324 TRX 625 BTS 1 TRX 1 SIG BTS 1 BCF SIG BTS 1 TRX 2 SIG
26 BTS 1 TRX 3 SIG BTS 2 TRX 1 SIG BTS 2 BCF SIG
27 BTS 2 TRX 2 SIG BTS 2 TRX 3 SIG
28 BTS 3 TRX 1 SIG BTS 3 BCF SIG BTS 3 TRX 2 SIG
29 BTS 3 TRX 3 SIG BTS 3 TRX 4 SIG
30 BTS 3 TRX 5 SIG BTS 3 TRX 6 SIG
31 Loop bits / LCB / MCB
BTS 11+1+1
BTS 21+1+1
BTS 32+2+2
Leased Lines2 Mbit Frame Allocation (Abis)
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Modulation
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Modulation is the process of encoding information from a message source in a manner suitable for transmission
Modulating signal = baseband signal Modulated signal = bandpass signal
Demodulation is the process of extracting the baseband message from the modulated carrier
Modulation TechnologiesBasics
Modulation
fc
bandpass
f0
baseband
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Modulation TechnologiesModulation in GSM
GMSK Gaussian Minimum Shift Keying
• Simple binary digital phase modulation scheme
• Excellent power and bandwidth efficiencies
Constant envelope & continuous phase • Noise-resistant
• Limited bandwidth
Implementation of transmitters and receivers are easy and cheap
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Channelization can be done by three methodsFDMA (Frequency Division Multiple Access)Each terminal (MS) has full time use of part of the spectral allocation. The FDMA technique divides the allocation in to a number of narrowband portions (channels). Each mobile station confines its signal energy within an allocated channel.
TDMA (Time Division Multiple Access )In TDMA each terminal has part time-use of part of the spectral allocation.TDMA technique breaks down the allocation in to a number of time slots (channels). Each mobile station confines its signal energy within an allocated time slot.
CDMA ( Code Division Multiple Access)In CDMA each terminal has full-time use of the entire spectral allocation and spreads its signal energy over the entire bandwidth. Base stations and terminals use codes unique to each signal to distinguish those signals coincident in time and frequency.
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GSM band is divided in to 200 KHz channels.
All the mobile technologies do not need very large bandwidth for single user communication. Because of Duplex requirements a pair of channels is required for simultaneous communication.
Power
FDMAFrequency
Time
Channelization MethodsChannelization Methods
FDMA FDMA
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FDMA / TDMA Grid
Frequency separation is 200 KHz in case of GSM and 30 KHz in case of IS-54
There are 8 time slots in case of GSM and 6 time slots in case of IS-54
Power
FDMA/TDMA Frequency
Ti me
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Channelization Methods
Power
Time
CDMA Channels
Frequency Channel is divided in to code channels.Each 1.25 MHz FDMA channel is divided in to 64 code channels
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Physical channel and TDMA frame
TDMA frame= 8 timeslots
01
23
45
76
01
23
45
76
01
23
45
200 kHz
Physcial channel, e.g. allocatedto one
subscriber with FR voice &no frequency hopping
frequencytim
e
TDMA frame
TDMA:
Is a method of sharing a resource (in this case a radio frequency) between multiple
Users by allocating a specific time (known as a time slot) for each user.
TDMA frame is defined as a grouping TSs that are numbered 0 to 7 as shown above.
Its has duration of 4.615ms ( 8 * 577us)
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Power Budget
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Installation Examples
Pole mounting for roof-top mounting
Tower mounting for directional antennas
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Antennas Categories
Omnidirectional antennas• Radiation patterns is constant in the horizontal
plain
• Useful in flat rural areas
Directional antennas• Concentrate main energy into certain direction
• Larger communication range
• Useful in cities, urban areas, sectorised sites
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Power BudgetBasics
Power budget is used to calculate the maximum allowed path loss
Main factors depend on equipment characteristics • BTS & MS TX power
• BTS & MS RX sensitivity
Other factors can be classified into 3 categories and have to be estimated
• Loss factors
• Gain factors
• Margins
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path loss = 154 dB
combiner loss = 5 dB
Feeder Loss = 4 dB
Rx Sensitivity- 102 dBm
Tx Power45 dBm (30W)
AntennaGain = 16dBi
- 102 dBm
52 dBm
36 dBm
40 dBm
Power BudgetDownlink
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path loss = 154 dBFeeder Loss = 4 dB
Tx Power33 dBm (2W)
AntennaGain = 16 dBi
DiversityGain = 4 dB
33 dBm
- 121 dBm
- 101 dBm
- 105 dBm
Rx Sensitivity -105 dB
Power BudgetUplink
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~ 3 … 5 dB losses 50 … 70% of
signal power is lost before even
reaching the TX antenna
Power BudgetLoss Factors
At BS side• Connectors (UL/DL)
• Cables (UL/DL)
• Isolator (DL)
• Combiner (DL)
• Filter (UL/DL)
At MS side• MS Antenna
– Polarization (UL/DL)
– Connection (UL/DL)
• External cable
man
y m
ete
rs
cables &connectors
filter
combiner
BS output
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Power BudgetGain Factors
At BS side
• Antenna gain (UL/DL)
– Main antenna parameter
– Slight difference between DL and UL
– The antenna models in use should be defined at the very beginning of the project
• Diversity gain (UL)
– Diversity can be implemented in many ways, with different gains
• LNA gain (UL)
• Booster or power amplifier gain (DL)
• Frequency hopping gain (UL/DL)
– FH improves average link quality, but it isn’t taken into account in power budget calculations
At MS side
• External antenna
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Erlang
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ErlangDefinition
Erlang is the unit of traffic• Definition
2 formulas• Erlang B: for systems that support no queuing
• Erlang C: for systems that support queuing
Seconds 3600
)()( Erlangs
timeonconversatiaveragehourpercallsx
Agner Krarup Erlang (1878-1929)
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Traffic Management
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Module ObjectivesAt the end of this module, you are able to:
• Subsystems of GSM
• Different network elements (generic architecture)
• Mobility concept (handover, location update, paging)
• Supplementary services offered by GSM networks
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BTS
Network Architecture
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System Overview
BaseStation
ControllerBSC
Public Switched
Telephone Network
BaseMobile Station
(MS)
MobileSwitching
CentreMSC
(PSTN)
StationSubsystem
(BSS)
A-Inter
A-bis
Um
2 Mbit/s PCMAir Interface
BTS
Base Transceiver
Station BTS
Base Transceiver
Station BTS
Base Transceiver
Station BTS
Base Transceiver
Station BTS
Base Transceiver
Station BTS
Base Transceiver
Station BTS
Equip. IdRegister
EIR
Authen.CentreAUC
VisitorLocationRegister
VLR
HomeLocationRegister
HLRMobile
SwitchingCentreMSC
MAPISUP / TUP
MAP
MAP MAP
ISUP / TUP
ISUP / TUP
MAP
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GSM Network Interfaces
Rf Test Equipment
PSTN
SS#7SS#7LAP-DLAP-DmAbis Interface
1
24
57
8*
0
3
6
9
#
1
24
57
8*
0
3
6
9
#
1
24
57
8*
0
3
6
9
# BTS
BTS
BTS
BSC
BSC
BSC
MSC
MSC
MSC
Um Interface
Protocol Analyzers
Protocol Analyzers
Protocol Analyzers
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System Building Blocks
HomeLocation Register
VisitorLocation Register
Mobile Switching Centre
BaseStation Controller
Base TransceiverStation
MSC BTSBSC
VLR
HLR
SONOFON
M N
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HLR (Home Location register)
“Home Base” of information regarding customers subscribing to a particular operators GSM network
Keeps track of subscriber profile, conditions and whereabouts
MSC BTSBSC
VLR
HLR
SONOFON
M N
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BTS
HLR contains
Subscriber information:
• IMSI (International Mobile Subscriber Identity)
• MSISDN (International Mobile Station ISDN Number)
• MS Category (e.g. payphone)
• Authentication vectors (RAND, SRES and Kc: AUC and SIM)
• Allowed services (subscription data)
Mobile location information:
• VLR number
• (MSRN - Mobile Station Roaming Number)
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VLR (Visitor Location register)Database with information about mobile users present/active in the network segment served by the MSC
Handles true visitors as well as subscribers of the operator himself
MSC BTSBSC
VLR
HLR
SONOFON
M N
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BTS
VLR contains.
Subscriber information:
• IMSI
• TMSI - Temporary Mobile Subscriber Identity
• MS category
• Authentication vectors
• Allowed services
Mobile location information:
• MSRN - Mobile Station Roaming Number
• LAI - Location Area Identity
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BTS (Base Transceiver Station)
Contains the radio transmitters and receivers (transceivers) covering a certain geographical area of the GSM network
MSC BTSBSC
VLR
HLR
SONOFON
M N
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BSC (Base Station Controller)
Controls a group of BTS’s in relation to power control and handover.
The combination of a BSC and its BTS’s is called a Base Station Subsystem (BSS).
The interface between the BTS & BSC and the is called the A-bis interface.
MSC BTSBSC
VLR
HLR
SONOFON
M N
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MSC (Mobile Switching Centre)Serves a number of BSS’s (Base Station Subsystem) via the A-interface.
Responsible for call control (set-up, routing, control and termination of the calls)
Management of inter-MSC handover and supplementary services, and for collecting charging/accounting information.
Gateway to other GSM networks and public-switched networks)
MSC BTSBSC
VLR
HLR
SONOFON
M N
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BTS
AUC - Authentication Centre
Contains the individual subscriber-identification key (also contained in the SIM), and provides the subscriber data to the HLR and VLR used for authentication and encryption of calls.
AUC
HLR
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BTS
EIR - Equipment Identity Registration
Stores information about mobile stations in use and may block calls from a MS if the MS is stolen, not type-approved or has faults which may disturb the network.
Each MS is identified by a unique International Mobile Station Equipment Identity (IMEI)
MSC
EIR
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BTS
TRAUTranscoder Rate Adaptation Unit
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BTS
TRAU
TRAU - Transcoder / Rate Adaptation Unit Functions:
• Conversion of speech from 64 kbit/s on PCM (A-law) to 16 kbit/s on the GSM radio interface
• Intermediate rate adoption of data from V.110 frames to the special TRAU frames on the A-bis interface
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Possible Locations of the TRAU
13Kbit/s speech channel
TRAU
BTS BSC MSC
BTS BSC MSC
BTS BSC MSC
TRAU
TRAU
Um A-bis A-Interface
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BTS
GSM Speech Encoding
Bandwidth: 13 kbit/s
Encoding algorithm: Regular Pulse Excitation with Long Term Prediction (RPE LTP):
• Speech is sampled 8000 times per second
• Each sample is converted into a 13 bit digital value
• Every 20 ms a 260 bit segment is generated (13 kbit/s)
• The segment is divided by importance into 182 class 1 bits and 78 class 2 bits
• For protection, the 182 class 1 bits are mapped into 378 bits
• The resulting 456 bits (378 + 78) are divided into 8x57 bits
• The data are transmitted in 4 consecutive TDMA blocks
Resulting overall delay is 57.5 msec.
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BTS
Control of TRAU
TRAU is controlled by BTS
In-band signalling used, if TRAU not at BTS
Control functions:
• Shift between speech and data
• Shift between full rate and half rate channels
• Timing of speech frames (BSS - MS)
• Comfort noise (Discontinuous Transmission)
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BTS GSM Bands
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GSM 900 Radio (Um) Interface Physical Channels
In GSM approx. 1000 radio channels has been assigned in the 900 MHz band. More precisely:
• 890 - 915 MHz “Uplink”
• 935 - 960 MHz “Downlink”
A combination of frequency and time division is used.
• 124 carriers
• Carrier spacing is 200 kHz
• 8 timeslots per carrier
BTS
Downlink
Uplink
Ch1 890
Ch124 915
Ch1 935
Ch124 960
SONOFON
M N
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DCS-1800 Radio (Um) Interface Physical Channels
In GSM 1800 2992 radio channels has been assigned in the 1800 MHz band. More precisely:
• 1710 - 1785 MHz “Uplink”
• 1805 - 1880 MHz “Downlink”
A combination of frequency and time division is used.
• 374 carriers
• Carrier spacing is 200 kHz
• 8 timeslots per carrier
BTS
Downlink
Uplink
Ch1 1710
Ch374 1785
Ch1 1805
Ch374 1880
SONOFON
M N
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GSM Bandwidth & Main Parameters900 MHz & 1800 MHz
GSM 900 :
GSM 1800 :
Channel spacing 200kHz
Usual bandwidth values (GSM900): 5 ..8 MHz per operator in one or more
sub-bands
1710 1785 1805 1880
duplex distance: 95 MHz
890 915 935 960
duplex distance: 45 MHz
Operator A Operator B Op. BOp. Anot allocated
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GSM 1900 :
2 x 60 MHz at channel spacing 200kHz ~300 channels
Band divided into sub-bands A..F
sub-bands A, B, C : 2 x 15 MHz spectrum
sub-bands D, E, F : 2 x 5 MHz
1850 1910 1930 1990
duplex distance: 80 MHz
Operator A Operator DOp. B Op. EOperator C Op. F
GSM Bandwidth & Main Parameters 1900 MHz
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GSM 900 GSM 1800• Frequency band 890 - 960 MHz 1710 - 1880
MHz
• Number of channels 124 (125) 372 (375)
• Channel spacing 200 kHz 200 kHz
• Multiplex technologies TDMA/FDMATDMA/FDMA
• Mobile power 0,8 / 2 / 5 W 0,25 / 1 W
There are no major differences between
GSM 900 and GSM 1800
GSM Bandwidth & Main Parameters
Summary
84 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS Radio Channels
85 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Same in GSM900 and GSM1800
FCH
Traffic Channels (TCH)
TCH/9.6FTCH/ 4.8F, HTCH/ 2.4F, H
Dedicated Channels
(DCH)
Broadcast Channel(BCH)
Control ChannelsCommon ControlChannel (CCCH)
SCH BCCH(Sys Info)
TCH/FAGCH RACH SDCCH FACCH/ Bm
FACCH/ Lm
TCH/HPCH
Common Channels (CCH)
Logical Channels
SACCH
Logical ChannelsOverview of Logical Channels
86 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Common Channels
87 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Logical ChannelsBroadcast Channels (BCH)
Frequency Correction Channel (FCCH)• Unmodulated carrier: like a flag for the MS which enables it to find the
frequency among several TRXs
Synchronisation Channel (SCH)• Contains the Base Station Identity Code (BSIC) and a reduced TDMA
frame number
Broadcast Control Channel (BCCH)• Contains detailed network and cell specific information as:
Frequencies, Frequency hopping sequence, Channel combination, Paging groups, Information on neighbour cells
• Careful frequency plan needed
• BCCH is not allowed to involve in Frequency Hopping
88 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Logical ChannelsCommon Control Channels (CCCH)
Paging Channel (PCH)• It is broadcast by all the BTSs of a Location Area in the case of a
mobile terminated call
Random Access Channel (RACH)• It is used by the mobile station in order to initiate a transaction, or as a
response to a PCH
Access Grant Channel (AGCH)• Answer to the RACH. Used to assign a mobile a SDCCH
89 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Radio (Um) Interface Common Control Channels
Broadcast: BCCH
• Carry system info intended for everybody, e.g. Location Area Identity
Paging: PCH
• To request a specific Mobile User to react/reply, e.g. when there is a call for him
Random Access: RACH
• Used by the Mobile Station to initiate contact with the network, e.g. when trying to start a call
Access Granted: AGCH
• Used to respond to the RACH to inform that the Mobile is now being allowed to access the network
90 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GSM BCH
Broadcast ChannelBroadcast Channel
One BCH on all the time, in every cellBCH Information carried in Timeslot 0 other Timeslots can be used for TCH or filled with dummy data
Allows Mobile to Synchronize
Identifies Network Carries Paging and other Control Information
91 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GSM RACH
Random Access ChannelRandom Access Channel
Used by the mobile to get attention
Mobile doesn't know path delay
So RACH has to be a special
SHORT BURSTSHORT BURST
Mobile sends normal burst after getting Timing Advance
92 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Dedicated Channels
93 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Logical ChannelsDedicated Channels (DCH)
Stand Alone Dedicated Control Channel (SDCCH)• System signalling: call set-up, authentication, location update,
assignment of traffic channels and transmission of SMS
Slow Associated Control Channel (SACCH)• Transmits measurement reports (UL)• Power control, time alignment, short messages (DL)
Fast Associated Control Channel (FACCH)• Mainly used for handover signalling• It is mapped onto a TCH and replaces 20 ms of speech
Traffic Channels (TCH)• Transfer user speech or data, which can be either in the form of Half
rate traffic (6.5 kbit/s) or Full rate traffic (13 kbit/s).
94 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Radio (Um) Interface Dedicated Control Channels
Stand-alone Dedicated : SDCCH
• Used for settling practicalities such as roaming, authentication, encryption and call control before allocating the traffic channel
Slow Associated: SACCH
• Associated to a TCH
• Used together with the Traffic Channel to deal with control and measurement of radio signals
Fast Associated: FACCH
• Large bandwidth version of the SACCH
• Used for sudden control action such as handovers
• Implemented a robbed bits in a TCH
95 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Radio (Um) Interface Logical Channels
Traffic channels (TCH):
• Carrying Voice/data
• Bm: 13 kbit/s user data
• Lm: Half rate (6,5 kbit/s)
Common control channels (CCCH):
• Channels that all Mobile Stations can share
Dedicated control channels (DCCH):
• Control channels for individual Mobile Stations
96 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GSM SACCH
Slow Associated Control ChannelSlow Associated Control Channel
DOWNLINKDOWNLINKMobile Tx Power Commands Mobile Timing AdvanceCell's Channel Configuration
UPLINKUPLINKReceived signal quality report (RXQual)Received signal level report (RXLev)Adjacent BCH power measurements Mobile's status
97 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GSM FACCH
Fast Associated Control ChannelFast Associated Control Channel
Used by BS and MS to send largeamounts of data FAST
Rapid message exchange for hand-offsControl Bits are either side of midamble:
Indicate if TCH or FACCH
98 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GSM SDCCH
Stand Alone Dedicated Control ChannelStand Alone Dedicated Control Channel
Used during Call Setup
Used for Short Messaging Services (SMS)
Stepping Stone between BCH and TCH
Used for Authentication Etc.
99 © Nokia Siemens Networks Presentation / Author / DateFor internal use
FCCH
SCH
PCH
AGCH
BCCH
CCCH
Common Channels
Dedicated Channels
Logical ChannelsDownlink
SACCHFACCH
SDCCH
TCH/F
TCH/H
DCCH
TCH
100 © Nokia Siemens Networks Presentation / Author / DateFor internal use
RACH CCCHCommon Channels
SDCCHSACCH
FACCH
TCH/F
TCH/H
DCCH
TCH
Dedicated Channels
Logical ChannelsUplink
101 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Search for frequency correction burst FCCHSearch for synchronisation sequence SCHRead system in formations BCCH
Listen for paging PCHSend access burst RACHWait for signalling channel allocation AGCHCall setup SDCCH
FACCHTraffic channel is assigned TCHConversation TCHCall release FACCH
idle mode
'off' state
dedicated mode
idle mode
Logical ChannelsUse
102 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
GSM Cell Structure
103 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Cell Structure
R5xR
F1
F2
F3 F
4
F5
F6
F4
Omni-directional BTS
3-directional BTS
Safety distance
BTS
BTS
BTS
BTS To avoid interference between two cells using the same frequency, a safety distance of about 5 times the cell radius is required.A BTS may cover one cell (Omni-directional) or several cells (typical three directional cells).Each cell may be served by one or more TRXs depending on the required capacity.
Note: each TRX controls one carrier with eight TS.
104 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Handovers
The Handover process is the situation where a Mobile Station changes from being served by one Antenna to another
Handovers take place during a call
Handover are done automatically
Crossing the boundary of two adjacent cells is the typical example of a Handover
BTS BTS
105 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GSM Hand-Off
1
2
4
5
7
8
*
0
3
6
9
#
BCH
TCHMobile constantly monitorsreceived TCH quality (RxQual & RxLev)
106 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Radio (Um) Interface Neighbour Cells
Mobile station in IDLE mode
• Besides listening to the BCCH and the PCH the mobile station is measuring for neighbour cells.
Mobile station in active mode
• In active mode the mobile station is using the time between the down and uplink TS (three TS 2ms) to do neighbour cell measuring.
The mobile station can measure up to 31 neighbour cells.
• In practice the mobile station measures up to 12 neighbour cells.
• Very often only three or four cells are measured.
107 © Nokia Siemens Networks Presentation / Author / DateFor internal use
HandoversMajor types of handovers
• Intra BSC
• Inter BSC
• Inter MSC
Purpose of handover
• Poor quality connection– Avoid loosing contact
to the mobile station
• Fault in the MS or BTS/BSC
• Network management
Intra BSC
Inter BSC
Inter MSC
BSC
MSC - A
MSC - B
BSC
BSC
BTS
BTS
BTSBTS
SONOFON
M N
SONOFON
M N
SONOFON
M N
108 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
GSMSignalling procedures
109 © Nokia Siemens Networks Presentation / Author / DateFor internal use
System Overview
BaseStation
ControllerBSC
Public Switched
Telephone Network
BaseMobile Station
(MS)
MobileSwitching
CentreMSC
(PSTN)
StationSubsystem
(BSS)
A-Inter
A-bis
Um
2 Mbit/s PCMAir Interface
BTS
Base Transceiver
Station BTS
Base Transceiver
Station BTS
Base Transceiver
Station BTS
Base Transceiver
Station BTS
Base Transceiver
Station BTS
Base Transceiver
Station BTS
Equip. IdRegister
EIR
Authen.CentreAUC
VisitorLocationRegister
VLR
HomeLocationRegister
HLRMobile
SwitchingCentreMSC
MAPISUP / TUP
MAP
MAP MAP
ISUP / TUP
ISUP / TUP
MAP
110 © Nokia Siemens Networks Presentation / Author / DateFor internal use
A functional model
Call Management (CM)
• Call Control (CC)
• SMS
• Non Call-related SS
Mobility Management (MM)
Radio Resource Management (RR)
CM
MM
RR
BTSBSC MSC
VLR
HLRSONOFON
M N
111 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Call Management (CM)
Call Management takes care of the ordinary call-control procedure:
• Establishment and release of calls, as well as access to services and facilities.
CM is divided into:
• Call Control (CC), short messages services (SMS).
• Non-call-related supplementary services (SS).
112 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Mobility Management (MM)
Mobility Management handles roaming and authentication procedure.
113 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Radio Resource Management (RR)Radio Resource Management comprise:
• Paging.
• Radio-channel access.
• Ciphering.
• Handover.
• Radio-signal control
• Radio-signal measurement
114 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Special signalling procedures for GSM
Call Management
• Ordinary Call Control (as usual)
Mobility Management
• Location Updating (Roaming)
• Authentication
Radio Resource Management
• Paging
• Network Access
• Encryption
• Radio Signal Control
• Radio Signal Measurements
• Handover
115 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Area 1
Area 2
BTS BTS
BTS BTS
Location Updating (Roaming)
An MM procedure
Reasons for roaming:
• MS has detected that it has entered into a new location area (by listening to Broadcast system info)
Types of roaming:
• Inside same VLR area– The HLR does not need to know
• Another VLR area– In this case the HLR is informed
MSC
VLR
MSC
VLR
SONOFON
M N
116 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Call Setup
A CM procedure
Distinguish two types
• Mobile Terminating Call – i.e. a call from the fixed network to a Mobile
Station
• Mobile Originating Call– i.e. a call from a Mobile Station to the fixed
network
117 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Mobile Terminating Call
Problems and answers
• Where in the world is the Mobile Station – Look it up in the HLR
– (The HLR may have to ask the VLR)
• How to Make the Mobile Station Aware that a call is waiting
– Page it in the cell where it is located
• What does the MS do when being paged ?– Asks for a Radio channel
– Tells the system that it is ready
Now the usual setup flow follows
118 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Mobile Originating CallProblems and Answers
• How the mobile gets in contact with the network– Switch the MS on
– Request a channel
– Tell the network what kind of service is wanted
• How does the network respond– Verifies the Mobile identity (authentication)
– Assigns a traffic channel
And then everything proceed as usual
119 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTSGSM Services
120 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Services
Telephony
Data services (up to 9600 b/s)
Fax group 3 (special modem)
Short Message Service (SMS)
Supplementary services, e.g.
• Call Forwarding
• Call Barring
• Call Waiting
• Three Party Service
• Advice of Charge
121 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
GSM Features
Integrated voice/data (ISDN)
Improved performance
Improved security
• Digital encryption
• Authentication (IMSI)
• TMSI assignment
All types of Mobile Stations
Automatic roaming
Sophisticated radio functions
• Discontinuous transmission - DTX
• Frequency hopping
122 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTS
Services, phase 2 and 2+Half-rate and enhanced full-rate speech
New supplementary services:
• Display of called and calling user's number
• Multi-party conversations (up to 6 parties)
• Closed user groups / virtual private networks
• Call completion services (busy, no answer etc.)
• Intelligent network services (CAMEL)
• Roaming between GSM and DCS 1800 (PCS 1900)
High speed data services:
• High Speed Circuit Switched Data (HSCSD)
• General Packet Radio Service (GPRS)
123 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Frequency Hopping
124 © Nokia Siemens Networks Presentation / Author / DateFor internal use
What is Frequency Hopping?
• Changing the carrier frequency in the radio link between mobile station and base station during the connection.
125 © Nokia Siemens Networks Presentation / Author / DateFor internal use
FHBasics
Frequency Hopping is a sequential change of carrier frequency on the radio link between BS and MS• It averages the interference (interference diversity) and
• Minimizes the impact of fading (frequency diversity)
It is a standardised feature it is supported by all mobilesFrequency
Time
F1
F2
F3
126 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BRTSL 0 1 2 3 4 5 6 7
TRX-1
TRX-2
TRX-3
TRX-4
f1 B = BCCH timeslot. It does not hop.
f2
f3
f4
Time slot 0 of TRX-2,-3,-4 hop over f2,f3,f4.
Time slots 1...7 of all TRXshop over (f1,f2,f3,f4).
The TRXs operate at fixed frequencies: consecutive bursts in each time slot are switched through different TRXs
The 1st time slot of the BCCH TRX is not allowed to hop
The number of frequencies to hop over is determined by the number of TRXs (biggest limitation!)
FHBase-Band Frequency Hopping
127 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BTRX-1
Non-BCCH TRXs are hopping overthe MA-list (f1,f2,f3,...,fn) attached to the cell.
TRX-2
B = BCCH timeslot. TRX does not hop.
f1,f2,f3,fn
f1,f2,f3,fn
. . . .
All the TRXs except the BCCH TRX change their frequency for every TDMA frame
Thus the BCCH TRX doesn’t hop at allThe number of frequencies to hop over is limited to 63, which is the maximum length of the Mobile Allocation (MA) list
FHSynthesised Frequency Hopping
BB-FH is feasible with large configurations
RF-FH is viable with smaller configurations
128 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Frequency hopping
RTSL 0 1 2 3 4 5 6 7
TRX-1 f1
TRX-2 f2
TRX-3 f3
TRX-4 f4
• Synthesized Hopping:
• Base Band Hopping:
TRX-1
TRX-2
f1,f2,f3,f4,
f1,f2,f3,f4,
.....
B
B
B = BCCH timeslot. It does not hop.
Time slots 1...7 of all TRXshop over MA(f1, f2, f3, f4).This hopping group uses HSN-2.
MAIOs have to be different between
same RTSLs in same hopping group.
0 0 0 0 0 0 0
1 1 1 1 1 1 1
2 2 2 2 2 2 2
3 3 3 3 3 3 3
0
1
2
Time slot 0 of TRX-2,-3,-4 hop over MA (f2, f3, f4).This hopping group uses HSN-1.
B = BCCH timeslot. TRX does not hop.
Non - BCCH TRXs are hopping overthe MA -list (f1,f2,f3,...,fn) attached to the cell.
fa
(fb)
(fc)
MAIOs have to be different between
same RTSLs in same hopping group.
Only one hopping group. Only HSN-1 is meaningful.
TRX-3
0 0 0 0 0 0 0 0
1 1 1 1 1 1 1 1
129 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Network Planning & Optimization
130 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Network planning team
• data acquisition• site survey and selection• field measurement evaluation• NW design and analysis• transmission planning
Network design• number and configuration of BS• antenna systems specifications • BSS topology• dimensioning of transmission lines• frequency plan• network evolution strategy
Network performance• grade of service (blocking)• outage calculations• interference probabilities• quality observation
Customer requirements• coverage requirements• quality of service• recommended sites• subscriber forecasts
External information sources• topo- & morphological data• population data• bandwidth available• frequency co-ordination• constraints
Interactions with• external subcontractors• site hunting teams• measurement teams• Operator• switch planning engineers
Network Planning Scope
131 © Nokia Siemens Networks Presentation / Author / DateFor internal use
CoveragePlanning andSite Selection
ParameterPlanning
PropagationmeasurementsCoverageprediction
SiteacquisitionCoverageoptimization
External Interference Analysis
NetworkConfigurationand
Dimensioning
PRE-PLANNING
DETAILED PLANNING
Traffic distributionService distributionAllowed blocking/queuingSystem features
IdentificationAdaptation
Area / Cellspecific
Handoverstrategies
Maximumnetworkloading
Other RRM
NetworkOptimization
POST-PLANNING
Surveymeasurements
Statistical performance analysis
Quality Efficiency Availability
Capacity Requirements
Requirementsand strategyfor coverage,quality and
capacity,per service
Network Planning Process General
132 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Network Optimisation
“Improving network quality from a subscribers point of view”
“Improving network quality from an operators point of view”
133 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Optimisation needed to...
Maximise/Maintain network Quality• Radio Network has to follow city developements
Achieve Quality Criteria set by• Operator:
• Key Performance Indicators balance investment versus achieved quality
• Subscriber:• 110% coverage propability everywhere
134 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Optimisation Flow Chart
Tools
KPI
Documentati
on
Analyzation
N
Case closed
YSolution worked ?
Solution
More info
needed ?
Y
N
HW change
Parameter change
Performance Analysis
O&MFT CC DB
135 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Optimisation Inputs and Tools
Operation & Maintenance• Statistics
• Alarms
• Parameters (NMS/BSS)
Field Tests (TOM/NEMO, TEMS)• Drive tests
• CW measurements
Customer Complaints
Database consistancy checks (NetAct)• Planning tool <-> BSS/NMS
136 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Optimisation Solutions
• Parameter changes• Frequency changes• Neighbour changes etc...
• Hardware changes• Antenna tilt• Antenna orientation• Antenna changes• HW check• Adding/deleting cell• Adding/deleting site• Adding/deleting TRX
137 © Nokia Siemens Networks Presentation / Author / DateFor internal use
NOKIA Implementation
138 © Nokia Siemens Networks Presentation / Author / DateFor internal use
DX 200 Platform
139 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Nokia Implementation of GSM Network
140 © Nokia Siemens Networks Presentation / Author / DateFor internal use
DX200 Platform Common Features
Distributed processing architecture
meeting the cost-effective capacity
requirement
Modularity (Plug-In Unit, PIU) enabling
HW/SW upgrade and maintenance
w/o traffic disturbance
Fault Tolerant Computing Platform
Cartridge mechanics
141 © Nokia Siemens Networks Presentation / Author / DateFor internal use
NOKIA i-series NE CabinetNOKIA i-series NE Cabinet
142 © Nokia Siemens Networks Presentation / Author / DateFor internal use
DX 200 Platform
Signalling towards subscribers
Collecting dialled numbers
Collecting the charging data
Hunting for a free circuit
Making speech path connections
Signalling towards other exchanges
Analyzing and subscriber data
Supervising the processes running
Collecting statistical data
143 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Exchange
Computer Units
Message bus
Signalling towards
Subscribers
Collecting dialled
numbers
Collecting Charging
data
Making Speech path
connections
Signalling towards
other exchanges
Collecting statistical data
Supervising the processes
running
Hunting for a free circuit
Distributed Processing of DX200Distributed Processing of DX200
144 © Nokia Siemens Networks Presentation / Author / DateFor internal use
SWITCHING
CONTROL
MANAGEMENT
SYNCHRONISATION AND TIMING
TRUNK NETWORK INTERFACE
ET
INTERFACE FOR
MOBILE ACCESS
ET
DX 200 Network Element
Basic Principles of DX200Basic Principles of DX200
145 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BCSU BSC Signaling Unit
BTS Base Transceiver
Station
CLS Clock & Sync. Unit
ET Exchange Terminal
GSWB Bit Group Switch
MB Message Bus
MCMU Marker and CellularManagement Unit
MSC Mobile Services
Switching Center
OMU Operation &
Maintenance Unit
BCSU BSC Signaling Unit
BTS Base Transceiver
Station
CLS Clock & Sync. Unit
ET Exchange Terminal
GSWB Bit Group Switch
MB Message Bus
MCMU Marker and CellularManagement Unit
MSC Mobile Services
Switching Center
OMU Operation &
Maintenance Unit
BSC Functional UnitsBSC Functional Units
146 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GSW
ET
ET
ET
ET
CLS
Message Bus
M OMUSignaling Unit
CM
TopologyFile Edit LocateView Help
Mount431 74371950 79%/
NetworkTraff ic Help
I/O
Additional Unit
DX200 ArchitectureDX200 Architecture
147 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Base Station Controller (BSC)Base Station Controller (BSC)
ET
GSW
PCU
BCSU
AS7
MSC/TCSM2
SGSN
BTS
MCMU
TCH (Circuit Switched) TCH (Circuit Switched)
Data (Packet Switched)Data (Packet Switched)
Signalling (CCS7)Signalling (LAPD)
ET ET
148 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Rack Layouts of the DX 200 BSC2iBCB BCE R2A1-SCC1
9V
BSC2i
27
27
27
CLSCLAC
O1
O1
O1
O1
PSA20_2 PSA20_3
PSFP2 PSFP3
PSA20_0 PSA20_1
PSFP0 PSFP1
BCSU 3MC1C
BCSU 4MC1C
BCSU 6MC1
CBCSU 7MC1C
BCMSU 8 MC1C
OMUMC1C
MCMU 1MC1C
MCMU 0MC1C
2701
O1
GSWB 0
SW1C0
GSWB 1
SW1C1
CLSCLOC
BCSU 5MC1C
O1
O1
27
27
27
BCSU 1MC1C
BCSU 2MC1C
BCSU 0MC1C
ET5C0
19
37CBD
8
002
120
088
058
030
152
ET5C8
ET5C7
ET5C1
01
13
ET5C3
ET5C4
ET5C2
ET5C6
ET5C5
SD3C-S
01
13
149 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BSC3i Cabinet and unit configuration
PDFU 0PDFU-A
GSWB 0SW1C-C
CL
S 0
,1C
LOC
-B
GSWB 1SW1C-C
ET4C 0ET4C-B
(32*ET2E/A)
ET4C 1ET4C-B
(30*ET2E/A)
FTRB 0 FTRB 1
FTRB 2 FTRB 3
CPRJ45 CPGOCPGO
PDFU 1PDFU-A
PDFU 2PDFU-A
PDFU 3PDFU-A
OMUCM2C-A
BCSU 1CC3C-A
BCSU 0CC3C-A
BCSU 2CC3C-A
BCSU 4CC3C-A
BCSU 3CC3C-A
BCSU 5CC3C-A
BCSU 6CC3C-A
CC4C-ACC4C-AMCMU 1MCMU 0
150 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Group Switch GSWB
2 3 4 5 6
SW
64B
SW
64B
SW
64B
PS
C1
SW
64B
SWBUS4
151 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Switching functionality
Group Switch (GSW/GSWB)
Purpose: The GSW is the switching matrix. The basic function is to switch dynamic connections, each input is capable of being switched to any output. Internal semipermanent connections are established with MML. GSWB of BSC is capable of bitwise switching. Belonging to the M-GSW switching entity, GSW is a subunit of Marker M.
Type: Functional unit
Redundancy: 2N
152 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Operation & Maintenance Unit for BSC3i
•1 •2 •4 •5 •6 •7•3 •8 •9 •10
•AP
•DBG
•RST
•J7
•J6
•WO
•RUN•LF•OL
•TE
•AP•DRAM
•SB
•CPSI
•SCSI•ETx0•ERx0
•OPR•OPR
•AP•AP
•OPR
•ON
•OFF
• PS
C6
-A
• MB
IF-B
0
• MB
IF-B
1
• CP
U
• AS
7-B
2 /
AC
25
-A
• AS
7-B
1 /
AC
25
-A
• AS
7-B
0
• SE
RO
-A
• HW
AT
-A
•ETx1•ERx1
• OD
PU
-A +
M0
91
• HD
PU
-A +
WD
W18
-S
• HD
PU
-A +
WD
W18
-S
•12 •13 •14
•SW0
•SW1
•RST
153 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Management functionality
Operation and Maintenance Unit (OMU)
Purpose: The OMU is the unit controlling the automatic self-repair functions of the network element, it monitors the exchange continuously and starts recovery procedures if errors occur. The OMU contains the user interface for the operating personal to do the normal operation and maintenance tasks. The OMU contains the interfaces for I/O system.
Type: Computer unit
Redundancy: 2N or no redundncy
154 © Nokia Siemens Networks Presentation / Author / DateFor internal use
MCMU for BSC3i
1 2 4 5 6 73
DBG
RST
J7
J6
WO
RUN
LF
OL
TE
AP
DRAM
SB
CPSI
SCSI
ETx0
ERx0
OPROPROPR
ON
OFF
PS
C6
-A
MB
IF-B
0
MB
IF-B
1
CP
U
SW
CO
P-A
ETx1
ERx1
ES
B2
0
J5
OPR
RST
ES
B2
0
J5
OPR
RST
ET
H1
ET
H2
ET
H1
ET
H2
155 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Control functionality
Marker (M)Purpose: The Marker controls and supervises the GSW.Type: Computer unit with subunitsRedundancy: 2N
Central Memory (CM) Purpose: The CM is one of the most important units in the network element. It is the central RAM of the exchange, which holds all the system software and also keeps a copy of all exchange specific software data. It is responsible for loading and updating data automatically to system's hard disks.Type: Computer unit with no subunitsRedundancy: 2NIn the BSC the common units Marker and Central Memory are integrated into the same functional unit called Marker and Cellular Management Unit (MCMU).
156 © Nokia Siemens Networks Presentation / Author / DateFor internal use
External interfaces
Exchange Terminal (ET)
Purpose: The ET is the unit which handles the external 2 Mbit/s PCM circuits through electrical synchronisation and adaptation of external 2Mbit/s.
Type: Functional unit
Redundancy: none
157 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Synchronisation and timing
Clock and Synchronisation Unit (CLSU)
Purpose: The CLSU is responsible for generating the synchronisation signals for different units.
Type: Functional unit
Redundancy: 2N
158 © Nokia Siemens Networks Presentation / Author / DateFor internal use
BSC Signalling Unit BCSU for BSC3i
1 2 4 5 6 73 8 9 10
AP
DBG
RST
J7
J6
WO
RUNLF
OL
TE
APDRAM
SB
CPSI
SCSI
ETx0
ERx0
OPROPR
APAP
OPR
ON
OFF
PS
C6-
A
MB
IF-B
0
MB
IF-B
1
CP
U
AS
7-B
2
AS
7-B
1
AS
7-B
0
PC
U-B
3
PC
U-B
4ETx1
ERx1
RUN0
RUN1
RUN0
RUN1
159 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Net element specific Control and Signalling units in BSC
Base Station Controller Signalling Unit (BCSU)
Purpose: The BCSU takes care of signalling towards the BSC and the MSC as well and controlling theBTS.
Type: Computer unit
Redundancy: N+1
160 © Nokia Siemens Networks Presentation / Author / DateFor internal use
DX200 Software StructureDX200 Software Structure
System block
Service block
Program block
161 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Software StructureSoftware Structure
A fundamental part of the DX200 system software is the real-time operating system kernel, DMXRTE, implemented in each Control Computer. The operating system is a platform for other system level software and all the application software.
The most significant functions of the operating system are:▪ Scheduling of processor time
▪ Synchronisation of processes
▪ Exchange of messages between processes located in one computer or separate computers
▪ Time supervision
▪ Creation and deletion of processes
▪ Memory allocation and protection
▪ Observation of message traffic and processor load
▪ Initialisation of the operating system.
162 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Nokia NMS
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Functional units in the NMS/2000
164 © Nokia Siemens Networks Presentation / Author / DateFor internal use
NOKIA NMS 2000
The standard Nokia NMS 2000 consists of servers and operator positions that can be either application workstations or X terminals. These components are connected to a Local Area network. Servers are also provided and consist of a communications server, a database server and a standby server or combinations of these. A router is provided to allow communications to the various elements in the GSM network, which is connected to a Data Communication Network (DCN)
165 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Network ElementsOMC (NMS)
Operation and Maintenance Center
(Network Management System)• Fault monitoring
• Alarm handling
• Performance measurements
• OMC is connected to GSM network e.g. via X.25 link
• Supervises all network elements
• Collects measurement data
• Remote handling of network elements
necessary tool for network optimisation
166 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Nokia BTS
167 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Network ElementsTasks of BTS
Base Transceiver Station• Maintain synchronisation to MS
• RF signal processing (combining, filtering, coupling...)
• Diversity reception
• Radio interface timing
• Detect access attempts of mobiles
• De-/ encryption on radio path
• Channel de-/ coding & interleaving
• Perform frequency hopping
• Forward measurement data to BSC
typically 1 - 4 TRX / sectortypically 1 - 3 sectorsavg. 7,5 traffic channels per TRX
168 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Network Elements Talk-family Base Station
Key Functionality
Nokia Intratalk (indoors) and Citytalk (outdoors) are base stations that can accommodate up to 12 TRX in omni or sectored configurations in two cabinets. Nokia Flexitalk Base Station is a compact Base Station with flexible configuration from 1 boosted TRX to 2 TRX omni configuration. The modular architecture and various antenna combinations help to achieve the best coverage and capacity solution. Nokia Talk-family base stations support GSM data evolution with the capabilty to support high speed circuit switched data (HSCSD) and GPRS.Key Benefits
• Flexible configurations and solutions from initial coverage building to large capacity sites • Smooth evolution path to 3G services with co-siting solutions • Protected investment through future-proofed expandability • Field-proven technology with high reliability
169 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Network Elements MetroSite
• The Nokia MetroSite GSM BTS is a complete, all-climate microcellular base transceiver station.
• It can be used in GSM 900, GSM 1800, GSM 1900 systems, or as a GSM 900/GSM 1800 dual band BTS.
• Both omni and sectored configurations are supported.
• The small-sized Nokia MetroSite GSM BTScabinet accommodates up to four transceiver units (TRXs).
• In order to ensure high quality of calls, the Nokia MetroSite GSM BTS supports versatile features, such as frequency hopping.
170 © Nokia Siemens Networks Presentation / Author / DateFor internal use
MetroSite Concept
Nokia MetroSiteBase Station
Connected to FXC RRI orFC RRI indoor unit.
Connected to FXC RRI orFC RRI indoor unit.
Nokia MetroHopper
Radio
Nokia MetroHubTransmission Node
Nokia FlexiHopperMicrowave Radio
Nokia MetroSiteBattery Backup
Nokia MetroSite Antennas
171 © Nokia Siemens Networks Presentation / Author / DateFor internal use
New MetroSite Family Members
Nokia MetroSite WCDMA Base Station
Nokia FlexiHopper Microwave Radio (PDH)
Nokia MetroHopper Radio
Nokia UltraHopper Microwave Radio (SDH)
High-power Nokia MetroSite GSM Base Station
Nokia MetroSite GSM Base Station
Nokia MetroHub Transmission Node
Nokia MetroSiteBattery Backup Unit
172 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Nokia MetroSite Base Station Antennas
Directional 130 degrees: 6 dBi Omnidirectional: 2 dBi
Dual band 2 port antennas
• GSM 900 / GSM 900
• GSM 900 / GSM 1800
• GSM 1800 / GSM 1800
1 feeder per TRX
No internal combiners needed
RX diversity
External 2 to 1 combiner available for special cases
173 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Network Elements PrimeSite
• Nokia PrimeSite is a complete 1 TRX Base Transceiver Station for both indoor and outdoor use in 900 MHz (GSM 900), 1.8 GHz (GSM 1800), and 1.9 GHz(GSM 1900) systems.
• The product has been optimized for one carrier.
• The number of TRXs can be increased by chaining several Nokia PrimeSites with a single clock synchronization cable between each unit.
• Nokia PrimeSite conforms to both GSM Phase I and Phase II requirements.
• The product is in link balance with 2WMS for GSM 900, and 1WMS for GSM 1800 and GSM 1900.
174 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Network Elements InSite
Key Functionality Nokia InSite Base Station is a compact, one-transceiver picocellular base station (BTS) for a variety of indoor coverage and capacity solutions. This tiny GSM/GPRS BTS is available in 900 and 1800 and 1900 MHz. Weighing just 2.4 kg and no bigger in area than a sheet of A4 paper, it can be installed virtually anywhere. Compact and integrated system elements, highly automated configuration and flexible transmission, means this base station can be installed in about one-tenth the time of other base stations giving fast return on investment. Rollout can cost a fraction of that of conventional indoor networks.
Key Benefits Dedicated indoor solution at a fraction of the conventional cost, means less capital expenditure • Single TRX picocellular base station for smooth growth of your indoor network • Highly automated and integrated system speeds up implementation and enables faster return on investment • Compatibility with future technology developments helps ensure cost-effective network upgrades • Network integration typically achieved during one site visit by one person
175 © Nokia Siemens Networks Presentation / Author / DateFor internal use
SMS
176 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Short Message Services (SMS)
Extremely popular service, similar to the peer-to-peer instant messaging services in the Internet
Allows exchange of alphanumeric messages up to 160 characters
Two types of services:
• Broadcast
• Peer to peer
Uses the same infrastructure as GSM
SMS has instant delivery service as well as store-and-forward service
177 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Operations
SMS makes use of the GSM infrastructure, protocols, and the physical layer to manage the delivery of messagesEach message is treated individually, and is maintained and transmitted by the SMS center (SMSC)Short messages (160 char mapped into 140 bytes) are transmitted through the GSM infrastructure using SS-7Short messages are transmitted in time slots that are freed up in the control channels
178 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Reference Architecture
HLR VLR
SMS-GMSCSMS-IWMSC
MSC
MS
SMSC
179 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Cases of Short Messages
SM originating from an MS
• Goes to MSC for processing
• SMS-interworking MSC (SMS-IWMSC forwards the SM to the SMSC
Mobile terminated short message
• SM is forwarded by the SMSC to the SMS-gateway MSC (SMS-GMSC)
• Either the HLR or VLR is queried
• SM is either delivered to the BSC or forwarded to another MSC
180 © Nokia Siemens Networks Presentation / Author / DateFor internal use
NEXT STEP
181 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Evolution of GSM
182 © Nokia Siemens Networks Presentation / Author / DateFor internal use
HSCSDBasics
High Speed Circuit Switched Data• Data rate up to 57.6 kbit/s
• Multiple set of basic resources (TCH) is reserved for one high speed data call
• Data rate and number of reserved timeslots can be defined by the user application
• S7 implementation of the feature is for up to 4 channels (each channel corresponds to 9.6/14.4 kbit/s)
. . .
PSTNISDNPDN
IWF
MSCBSC/TRAUBTS
183 © Nokia Siemens Networks Presentation / Author / DateFor internal use
New Applications & Uses Feasible
GPRSBasics
General Packet Radio Service
End User (compared to 9.6 data & HSCSD): • Service differentiation opportunities
• Always connected
• Pay per bit transferred
• Higher speeds
• Faster session set up
Operator:• Service differentiation opportunities
• Catch Corporate business (including speech)
• Additional revenue for content
• Get more use out of network investment
• Path to 3rd Generation
184 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Introduction
GPRS (General Packet Radio Service)
• Reuse the existing GSM infrastructure
• Introduce packet-switched routing functionality– Better data transfer rates
– Low cost and connectivity-oriented
• Migration Path to 3G Networks
185 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GPRS - Overview
GPRS is an overlay on top of the GSM physical layer and network entities
Extends data capabilities of GSM
Provides connections to external packet data networks through the GSM infrastructure with short access time to the network for independent short packets (500-1000 bytes)
No hardware changes required for Base Station
Scalable, high throughput (21.4 kbps), support for voice and data
186 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GPRSCircuit Switched vs. Packet Switched
Circuit Switched
Packet Switched
187 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Packet-switched techniquevs. circuit-switchedIn circuit-switching, resources (e.g. a channel) are allocated to user for duration of connection
• Inefficient use of resources
• User pays for the whole connection
• High QoS: channel maintains real-time connection
In packet-switching, resources are allocated to user only for the time it takes to send each packet
• A channel can serve many users
• User pays by the packet
• Ideal for bursty data connections
188 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Comparison
Packet-switched
• High bit rates (up to 170kbit/s)
• Shared bandwidth
• Variable access times
• Friendly bill (based on volume)
• Robust application support– Frequent transmission of small
volumes
– Infrequent transmission of small or medium volumes
Circuit-switched
• Low bit rates (14.4kbit/s)
• Reserved bandwidth
• Fixed access time
• Unfriendly bill (based on duration)
• Limited application support– Large volumes
189 © Nokia Siemens Networks Presentation / Author / DateFor internal use
13 ©NOKIA CTXX 3218_3.0en.PPT / 14.09.2001
Telephone networks
Packet switched
Datanetworks
• End-to-end connection (call) establishment needed
• Dedicated resources (e.g. PCM-tsl) for one user are reserved during call establishment
• Only 30 - 40% of resources are effectively used for speech transfer
• Speech is transferred in real time
• Speech does not accept delays
• Errors in transmission are not so critical for speech
• Charging is usually based on time
• No connection needed
• Resources are shared between different user sessions, not dedicated
• Resources are requested on demand, more efficient use
• Packets are not sent in real time buffering and delay
• Error correction and detection possible
• Charging is usually based on volume number of packets
Circuit switched
190 © Nokia Siemens Networks Presentation / Author / DateFor internal use
14 ©NOKIA CTXX 3218_3.0en.PPT / 14.09.2001
Telephone networks
Packet switched
Datanetworks
Physical circuitPCM-tsl(CONS)
• End-to-end connection (call) establishment needed
• Dedicated resources (e.g. PCM-tsl) for one user are reserved during call establishment
• Only 30 - 40% of resources are effectively used for speech transfer
• Speech is transferred in real time• Speech does not accept delays• Errors in transmission are not so critical
for speech• Charging is usually based on time
Virtual circuit (VC) No VCX.25 IP
(CONS) (CLNS)
• No connection needed• Resources are shared between different
user sessions, not dedicated• Resources are requested on demand, more
efficient use• Packets are not sent in real time
buffering and delay• Error correction and detection possible• Charging is usually based on volume
number of packets
Circuit switched
191 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GPRS Architecture
192 © Nokia Siemens Networks Presentation / Author / DateFor internal use
MSC
SS7 signalingNetwork
PSTN
ISDN
BSCBTS
IP networksInternet
Packet Core
IP BackboneFirewall
Gateway GPRSSupport Node
Serving GPRS
Support Node
HLR
GGSN
SGSN
GPRSNetwork Overview
193 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GPRS Architecture - Components
New components introduced for GPRS services:
• SGSN (Serving GPRS Support Node)
• GGSN (Gateway GPRS Support Node)
• IP-based backbone network
Old components in GSM upgraded for GPRS services:
• HLR
• MSC/VLR
• Mobile Station
194 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Reference Architecture
Refer to handout
Uses GSM architecture
GPRS support nodes (GSN): responsible for delivery and routing of data packets between the MS and the external network
Serving GPRS support node (SGSN)
• Controls access to MSs that are attached to a group of BSCs (routing area (RA) of SGSN)
Gateway GPRS support node (GGSN)
• Logical interface to the Internet
GPRS Register (GR)
• Colocated with HLR and stores routing information
195 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GPRS ArchitectureSGSN – Serving GPRS Support Node
At the same hierarchical level as the MSC.
Transfers data packets between mobile stations and GGSNs.
Keeps track of the individual MSs’ location and performs security functions and access control.
Detects and registers new GPRS mobile stations located in its service area
Participates into routing, as well as mobility management functions.
196 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GPRS ArchitectureGGSN – Gateway GPRS Support Node
Provides inter-working between PLMN and external packet-switched networks.
Converts the GPRS packets from SGSN into the appropriate packet data protocol format (e.g., IP or X.25) and sends out on the corresponding packet data network.
Participates into the mobility management.
Maintains the location information of the mobile stations that are using the data protocols provided by that GGSN.
Collects charging information for billing purpose.
197 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GPRS ArchitectureBackbone Network
Tunnels of data and signaling messages between GPRS support nodes.
Protocol architecture based on the Internet Protocol (IP).
GTP (GPRS Tunneling Protocol) used to tunnel user data and signaling between GPRS Support Nodes. All PDP (Packet Data Protocol) PDUs (Protocol Data Units) shall be encapsulated by GTP.
198 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GPRS ArchitectureBackbone Network (cont.)
Two kinds of GPRS backbone Network:
• Intra-PLMN backbone network: The IP network interconnecting GSNs within the same PLMN.
• Inter-PLMN backbone network: The IP network interconnecting GSNs and intra-PLMN backbone networks in different PLMNs.
Two intra-PLMN backbone networks are connected via the Gp interface using Border Gateways and an inter-PLMN backbone network.
Border Gateway handles the packet transfer between GPRS PLMNs.
199 © Nokia Siemens Networks Presentation / Author / DateFor internal use
SW Upgrade in MSC/VLR and HLR
GPRS capable MS
NMS Upgrade to T12
MSC
ISDN/PSTN
NetworkEIR
HLR/AuC
SMSC
BSC
BTS
Um
HW and SW Upgrade in BSC (S9+PCU)
SW Upgrade in BTS
Internet or
Corporate LAN
GPRS Core
Network
GPRS Core Network Elements
New Services (APNs, WAP)
GPRSHW & SW Upgrades from GSM
200 © Nokia Siemens Networks Presentation / Author / DateFor internal use
GPRS ArchitectureInterfaces
TE MT BSS SGSN GGSN PDN TE
MSC/VLR HLR
SGSNCGF
EIR
BillingSystem
Other PLMN
GGSN
R Um
AGs
DGr
Gc
Gb Gn Gi
Gn Gp
Gf
GaGa
• CGF(Charging Gateway)
201 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Packet transfer
Intra-PLMN backbone
PLMN
202 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Packet Transfer
A laptop connects with a GPRS-capable handset.
The handset communicates with GSM base station.
Base station sends the GPRS packets to SGSN.
SGSN encapsulates packets
Handset location information is updated in other GSM components, such as HLR.
SGSN sends encaps. packets to GGSN.
GGSN decapsulates and sends to PDNs.
203 © Nokia Siemens Networks Presentation / Author / DateFor internal use
204 © Nokia Siemens Networks Presentation / Author / DateFor internal use
205 © Nokia Siemens Networks Presentation / Author / DateFor internal use
What is Traffic Management?
Traffic Management Procedure is subdivided into 2 areas:
1. What is Mobility Management?• Procedures that take care of the mobility of the user, such as the
GPRS attach, are called GPRS Mobility Management (GMM).
– The GMM procedures are similar to the mobility management for circuit switched users.
– Examples: GPRS Attach, GPRS Detach, Cell Update, Intra-SGSN Routing Area Update
2. What is Session Management?• Procedures that handle the GPRS MS connection management
to the external data networks are called Session Management (SM).
– Examples: PDP Context Activation
206 © Nokia Siemens Networks Presentation / Author / DateFor internal use
What sort of procedures are needed?
• MS switches on for the first time.
• MS indicates that it is switched on and ready. (GPRS Attach)
• MS indicates that it is switched off. (GPRS Detach)
• MS indicates that it wants to transmit data. (PDP Context Activation)
• MS indicates to stop data transmission. (PDP Context Deactivation)• • MS moves from one part to another of a service area. (Cell Update
and RA Update procedure)
• MS may roam into another networks service area. (Roaming)
• etc.
207 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Types of subscriber information Subscriber Identity
—How do we uniquely identify a subscriber?– IMSI, TMSI, IP Address
—Where will this information be maintained?
Subscriber Location —How do we know the location of the subscriber?
– Location Area (LA) and Routing Area (RA)
—Where will this information be maintained?
Subscriber Services —What sort of services is a subscriber allowed to access?—Where will this information be maintained?
Subscriber Authentication —What information is needed to authenticate the subscriber?
– Ki Algorithms, Triplets
—Where will this information be maintained?
208 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Type of info What info Where
Identity IMSI
TMSI
IP address
SIM, HLR, VLR,SGSN, GGSN
VLR, SGSN
MS, SGSN, GGSN
Location VLR-address
Location Area
Serving SGSN
Routing Area
HLR
SGSN, VLR
HLR, VLR
SGSN
Services Basic services,supplementary services,circuit switched bearerservices, GPRS serviceinformation
Basic services,supplementary services,CS bearer services
GPRS service information
HLR
VLR
SGSN
Authenticationdata
Ki, algorithms
Triplets
SIM, AC
VLR, SGSN
209 © Nokia Siemens Networks Presentation / Author / DateFor internal use
21 ©NOKIA CTXX 3218_3.0en.PPT / 14.09.2001
What are the advantages of GPRS to operators?• More revenue
• Huge potential market for data services—Data traffic rising faster than voice
• Fast roll-out and continuous network expansion—Operators can start small and develop GPRS capacity as traffic and
revenue start to increase
• GPRS uses excessive voice capacity for data (see next slide)
• Smooth path to 3G services (Covered in Evolution from 2G to 3G module)
210 © Nokia Siemens Networks Presentation / Author / DateFor internal use
EDGEBasics
Enhanced Data rate for Gsm Evolution (EDGE)• Update of the GSM standard towards 3G networks/mobiles
• Operators who do not get/want 3G-license (UMTS/WCDMA) can provide 3G-services anyway
• Enhancement results from introduction of new modulation (8-PSK) + channel coding schemes
• ECSD (Enhanced Circuit Switched Data): circuit switched channels/services. Updates HSCSD for 8-PSK modulation
• EGPRS (Enhanced GPRS): packet switched channels/services. Updates GPRS for 8-PSK modulation
211 © Nokia Siemens Networks Presentation / Author / DateFor internal use
EDGEEDGE in GSM/GPRS Networks
EDGE 8-PSK coverage
EDGE capable TRX, GSM compatible
EDGE GMSK coverage
A-bisBTS
BTS
MSC
Gn
GGSN
EDGE capable terminal,
GSM compatible
More capacity in interfaces to support higher data usage
GbBSC
A
SGSN
EDGE functionality in the network elements
212 © Nokia Siemens Networks Presentation / Author / DateFor internal use
EDGE
The fundamentals difference between GSM/GPRS and EDGE is that EDGE uses 8 PSK modulation, which encodes 3 bits per modulated symbol, compared with 1bit per symbol GMSK that is used for GSM and GPRS network.
EDGE will enable data rates of upto 473 Kbits/s per TRX for Enhanced GPRS (E-GPRS), with slightly reduced coverage.
Ability to handle Wireless multimedia services, Internet / Intranet, Videoconferencing and fast electronic mail transfer.
213 © Nokia Siemens Networks Presentation / Author / DateFor internal use
UMTSStandardisation
214 © Nokia Siemens Networks Presentation / Author / DateFor internal use
UMTSNetwork Architecture
Core NetworkRAN
Air
Air
Air
Iupacket
Iucircuit
Iur
Iur
RNC
RNC
RNC
Iub
Iub
Iub
BS
BS
BS
BS
BSBS
BSMSC
Serving GPRSSupport Node(SGSN type U)
IWUTC
IuIu
Circuit Domain
Packet Domain
215 © Nokia Siemens Networks Presentation / Author / DateFor internal use
UMTS UL(FDD)
60 MHz
UMTS(TDD)
20 MHz
1920
1900 2000 2100 2200
UMTS DL(FDD)
60 MHz
1980 2110 2170
UMTS(TDD)
15 MHz
20102025
UMTSAllocated Bandwidth
216 © Nokia Siemens Networks Presentation / Author / DateFor internal use
5 MHz
3.84 MHz
f
Guard Bands
UMTSWCDMA Carrier
217 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Frequency
Pow
er
den
sity
(W
att
s/H
z)
Unspread narrowband signal
Spread wideband signal
W
R
UMTSSpreading / Despreading
A narrowband signal is spread to a wideband signal
218 © Nokia Siemens Networks Presentation / Author / DateFor internal use
High bit rates
Spectral efficiency
Different qualityrequirements
Efficient packet data
Downlink capacity
WCDMA GSMCarrier spacing 5 MHz 200 kHz
Frequency reuse factor 1 1–18Power control frequency 1500 Hz 2 Hz or lower
Quality control Radio resource management algorithms
Network planning (frequency planning)
Frequency diversity 5 MHz bandwidth gives multipath diversity with
Rake receiverFrequency hopping
Packet data Load-based packet scheduling
Time slot based scheduling with GPRS
Downlink transmit diversity
Supported for improving downlink capacity
Not supported by the standard, but can be
applied
UMTSDifferences with GSM
219 © Nokia Siemens Networks Presentation / Author / DateFor internal use
3rd Generation Mobile Systems
A Summary of the main objectives for the IMT – 2000 air interface is shown below
Full coverage and mobility for 144Kbits/s, preferably 384Kbits/s
Limited coverage and mobility for 2 Mbits/s
Efficient use of the radio spectrum compared with existing systems
Flexible architecture to allow
the introduction of new
services
220 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Combined GSM and WCDMA Network
221 © Nokia Siemens Networks Presentation / Author / DateFor internal use
WCDMA Network
222 © Nokia Siemens Networks Presentation / Author / DateFor internal use
W-CDMA (Wideband CDMA)
For the 3rd Generation mobile systems, a high bit rate is required for multimedia data. Therefore, the spreading code must be of a higher bit rate.
IS 95 CDMA uses a bandwidth of 1.25MHz, but
W-CDMA systems for UMTS will occupy a bandwidth of 5MHz.
In the W-CDMA system the spreading codes are used to spread out the data signal to cover the whole wideband spectrum that is allocated for the data transfer.
223 © Nokia Siemens Networks Presentation / Author / DateFor internal use
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