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Presentation on GSM
Network
RAVI KUMAR
KHANDELWAL
VII SEM
EC-B
PRERAK KUMAR
JOSHI
VII SEM
EC -B
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COMPANY
Nokia SiemensNetworks
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NOKIA SIEMENS
Telecom Service Provisions
GSM
Basic
Internet
GSM Service Provider in INDIA
Basic Service Provide FOR VODAFONE.
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ORGANISATION STRUCTUREPROMOTERS
TECHNICAL PLANNING
IMPLEMENTATION OPERATIONS
OPERATIONS SYSTEM SUPPORT BILLING
IT ACTIVATIONS
MARKETING
CUSTOMER CARESALES
SUPPORT FUNCTIONS HR, ADMIN, ACCOUNTS
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Cellular Communication
A cellular system links Mobile subscribers to
Public Telephone System or to another Mobile
subscribers.
It removes the fixed wiring used in a traditional
telephone installation.
Mobile subscriber is able to move around,
perhaps can travel in a vehicle .
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The CELL
What is a cell ?
A cell is a certain area
that can be reached
with one transceiver
or
A small collection of
transceivers on
different channels at a
single base site.
The hexagonal-shaped communication cells are
artificial & are generated to simplify the planning &
design of a cellular network.
BTS
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Cells
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What is GSM ?
Global System for Mobile (GSM)
is a second generation cellular
standard developed to cater voice
services and data delivery using
digital modulation.
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GSM - IN CELLULAR TELEPHONY
Each Cell in the Cellular Network consists of
one or more RF carriers.
An RF carrier is a pair of radio frequencies One used in upward direction by MS - Uplink
Other used in downward direction by BTS -
Downlink
The transmit and receive frequencies are
separated by a gap of 45 MHz in GSM of 75 MHz
in DCS.
There are 124 carries in GSM Band. With each
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Uplink-Downlink
Downlink = 935 to 960 MHz
Uplink = 890 to 915 MHz
BTS Tx MS Rx
BTS Rx MS Tx
dl
ul
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SERVICES
It contains two phases. Phase 1 Phase 1 contains the most common services including: Voice telephony International roaming Basic fax/data services (up to 9.6 kbits/s) Call forwarding
Call barring Short Message Service (SMS) Phase 1 also incorporated features such as ciphering and Subscriber Identity Module (SIM) cards.
Phase 1 specifications were then closed and cannot be modified.
Phase 2 Additional features were introduced in GSM phase 2 including: Advice of charge Calling line identification Call waiting Call hold Conference calling Closed user groups Additional data communications capabilities
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GSMSyst r it t r
BSC
BSC
MSC
MS
MS
MS BTS
BTS
BTS
GMSC
PSTNISDNPDN
EIR
UC
HLR
VLR
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GSM System Architecture-I Mobile Station (MS)
Mobile Equipment (ME)
Subscriber Identity Module (SIM)
Base Station Subsystem (BSS)
Base Transceiver Station (BTS)Base Station Controller (BSC)
Network Switching Subsystem(NSS)
Mobile Switching Center (MSC)
Home Location Register (HLR)
Visitor Location Register (VLR)
Authentication Center (AUC)
Equipment Identity Register (EIR)
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System Architecture
Mobile Station (MS)
The Mobile Station is made up of two
entities:1. Mobile Equipment (ME)
2. Subscriber Identity Module (SIM)
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System Architecture
Mobile Station (MS)Mobile Equipment
Portable,vehicle mounted, hand helddevice
Uniquely identified by an IMEI(International Mobile Equipment Identity)
Voice and data transmission Power level : 0.8W 20 W
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System Architecture
Mobile Station (MS) contd
Subscriber Identity Module (SIM)
Smart card contains the International
Mobile Subscriber Identity (IMSI) Allows user to send and receive calls andreceive other subscribed services
Encoded network identification details- Key Ki,Kc and A3,A5 and A8 algorithms
Protected by a password orPIN Can be moved from phone to phone
contains key information to activate the ph
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SIM
Subscriber Identity Module
The SIM stores
Subscriber Parameters
Personal Data for identifying
Subscriber to the Network.
IMSI,, MSISDN, PIN, PUK, Ki,
(for Kc generation)
Space reserved for TMSI & LAI
--------
------
--------
------
Small SIM
Full Size SIM Card
--------
------
--------
------
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System Architecture
Base Station Subsystem (BSS)Base Station Subsystem is composed of
two parts that communicate across the
standardized Abis interface allowing
operation between components made by
different suppliers
1. Base Transceiver Station (BTS)
2. Base Station Controller (BSC)
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A BTS Cabinet
OUTER VIEWINNER VIEWNETC
OMP
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System Architecture
Base Station Subsystem (BSS)-Base Transceiver Station (BTS):
Encodes,encrypts,multiplexes,modulatesand feeds the RF signals to the antenna.
Communicates with Mobile station and
BSC
Consists of Transceivers (TRX) units
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System Architecture
Base Station Subsystem (BSS)
Base Station Controller (BSC):
Manages Radio resources forBTS
Assigns Frequency and time slots for allMSs in its area
Handles call set up
Transcoding and rate adaptation
functionality Handover for each MS
It communicates with MSC and BTS
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System Architecture
NetworkSwitching Subsystem(NSS)
Mobile Switching Center (MSC) Heart of the network Manages communication between GSM and
other networks
Call setup function and basic switching Call routing Billing information and collection Mobility management
- Registration
- Location Updating- InterBSS and inter MSC call handoff
MSC does gateway function while its customerroams to other network by using HLR/VLR.
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MOBILE SWITCHING CENTRE
NETC
OMP
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System Architecture
Network Switching Subsystem Home Location Registers (HLR)
- Permanent database about mobile subscribers ina large service area(generally one per GSMnetwork operator)
- Database containsIMSI,MSISDN,prepaid/postpaid, roamingrestrictions,supplementary services.
Visitor Location Registers (VLR)- Temporary database which updates whenever
new MS enters its area, by HLR database- Controls those mobiles roaming in its area- Reduces number of queries to HLR- Database contains
IMSI,TMSI,MSISDN,MSRN,LocationArea,authentication key
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System Architecture
Network Switching Subsystem
Authentication Center (AUC)- Protects against intruders in air interface- Maintains authentication keys and
algorithms and provides security triplets (RAND,SRES,Kc)
- Generally associated with HLR
Equipment Identity Register (EIR)- Database that is used to track handsets
using the IMEI (International MobileEquipment Identity)
- Made up of three sub-classes: The WhiteList, The Black List and the Gray List
- Only one EIR perPLMN
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GSM Specifications-1
RF Spectrum
GSM 900Mobile to BTS (uplink): 890-915 MHzBTS to Mobile(downlink):935-960 MHzBandwidth : 2* 25 MHz
GSM 1800
Mobile to BTS (uplink): 1710-1785 MHzBTS to Mobile(downlink) 1805-1880 MHzBandwidth : 2* 75 MHz
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GSM Specification-II
Carrier Separation : 200 KHz
Duplex Distance : 45 MHz
No. of RF carriers : 124 Access Method : TDMA/FDMA
Modulation Method : GMSK
Modulation data rate : 270.833 Kbps
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Call Routing
Call Originating from MS
Call termination to MS
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Outgoing Call1. MS sends dialed number to
BSS2. BSS sends dialed number to
MSC3,4 MSC checks VLR if MS is
allowed the requested
service. If so, MSC asks BSSto allocate resources for call.
5 MSC routes the call to GMSC6 GMSC routes the call to
local exchange of called user
7, 8,9,10 Answer back(ring back)
tone is routed from calleduser to MS viaGMSC,MSC,BSS
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Incoming Call
1. Calling a GSM subscribers2. Forwarding call to GMSC3. Signal Setup to HLR4. 5. Request MSRN from VLR
6. Forward responsible MSCto GMSC
7. Forward Call to currentMSC
8. 9. Get current status of MS
10.11. Paging of MS12.13. MS answers14.15. Security checks16.17. Set up connection
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Handovers
*Between 1 and 2 Inter
BTS / Intra BSC
*Between 1 and 3 Inter
BSC/ Intra MSC
*B
etween 1 and 4
InterMSC
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Characteristics of GSM Standard
Fully digital system using 900,1800 MHz frequencyband.
TDMA over radio carriers(200 KHz carrier spacing.
8 full rate or 16 half rate TDMA channels per carrier.
User/terminal authentication for fraud control. Encryption of speech and data transmission over the
radio path.
Full international roaming capability.
Low speed data services (up to 9.6 Kb/s).
Compatibility with ISDN.
Support of Short Message Service (SMS).
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Japanese
Hebrew
ThankYou
English
MerciFrench
Russian
DankeGerman
GrazieItalian
GraciasSpanish
ObrigadoPortuguese
Arabic
Simplified Chinese
Traditional Chinese
Tamil
Thai
Korean
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