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Submitted By :- Ankita SoganiRoll no :- 17Batch :- E.C.E (A-1 )
Under taken at:-
ERICSSION INDIA PVT. LTD.
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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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Developed by Group Spéciale Mobile (founded 1982) which was aninitiative of CEPT ( Conference of European Post andTelecommunication )
Aim : to replace the incompatible analog system
Presently the responsibility of GSM standardization resides withspecial mobile group under ETSI ( European telecommunicationStandards Institute )
Full set of specifications phase-I became available in 1990
Under ETSI, GSM is named as ³ Global System for Mobilecommunication ³
Today many providers all over the world use GSM (more than135countries in Asia, Africa, Europe, Australia, America)
More than 1300 million subscribers in world and 45 million subscriber in India.
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Improved spectrum efficiency
. International roaming
. Low-cost mobile sets and base stations
. High-quality speech
. Compatibility with ISDN and other telephonecompany services.
. Support for new services
. Q o S
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1.Tele Services
Telecommunication services that enable voice communication by mobile phones.
Offered services:- Mobile telephony, Emergency calling
2.Bearer Services
Include various data services for information transfer between GSM and other
networks like PSTN, ISD N etc.
Short Message Service (SMS), fax, voice mailbox, electronic mail,etc.
3.Supplementary Services
Call Waiting
Call Hold
Call Barring
Call Forwarding
Call Conferencing
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A cell is the basic unit of a cellular system and is defined as the area of
radio coverage given by one BS antenna system. Each cell is assigned a
unique number called Cell Global Identity (CGI).
advantage
Frequency reuse ² same frequency in many cell sites
Cellular expansion ² easy to add new cellsHandover ² moving between cells
The reuse frequency distance
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M acrocells(3 to 35 km)M icrocells(0,1 to 1 km)
Picocells(0,01 to 1km)
Nanocells(1m to 10m
Umbrella cells covers several microcells
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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)
A uthentication Center
( AUC)
Equipment Identity
Register (EIR)
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Mobile Equipment
Portable, vehicle mounted, hand held device. Uniquely identified by an IMEI (International Mobile Equipment
Identity). Voice and data transmission . Monitoring power and signal quality of surrounding cells for
optimum handover. Power level : 0.8W ² 20 W 160 character long SMS.
Subscriber Identity Module (SIM)
A llows user to send and receive calls and receive other
subscribed services Smart card contains the International Mobile Subscriber Identity
(IMSI) Encoded network identification details Key Ki, Kc and A3, A5 and A 8 algorithms Protected by a password or PIN Can be moved from phone to phone ² contains key information to
activate the phone
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Base Transceiver Station (BTS)
Encodes,encrypts,multiplexes,modulates and feeds the RF
signals to the antenna.
House the radio transceivers of the cell.
Communicates with Mobile station and BSC.
Handle the radio link protocols.
Base Station Controller (BSC)
The BSC is the connection between the mobile station and theMobile service Switching Center (MSC).
Manages Radio resources for BTS. A ssigns Frequency and time slots for all MS·s in its area. Handles call set up. Handover for each MS.
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Mobile Switching Center (MSC)
Heart of the network. Manage communication between GSM and other networks. Identify the origin , destination and type of the call. Billing information and collection.
supervises operation of the rest of the network components Mobility management GMSC: Gateway MSC act as a bridge between mobile network and
fixed network.
Home Location Register (HLR)
It acts as a permanent store for a person's subscription informationuntil that subscription is canceled.
The information stored includes:
Subscriber identity
Subscriber supplementary services
Subscriber location information
Subscriber authentication information
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Visitor Location Register (VLR)
Temporary database which updates whenever new MS enters its area, by HLR
database Controls those mobiles roaming in its area . Database contains IMSI,MSISD N,MSR N,Location Area, authentication key Tracks and periodically updates the database on which phones are turned on
and ready to receive a call.
Authentication Center (AUC)
Authenticate the subscribers. Ciphering keys used to ensure network security. 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 White List, The Black List and the GrayList.
Only one EIR per PLM N.
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The initial design used the 900 MHz range Uplink to BTS 890 - 915 MHz Downlink to MS 935 - 960 MHz Duplex distance 45MHz Carrier Seperation 200KHz There are 124 channels A nd each channel can carry 8
TDM A users Modulation GMSK Usually an operator does not have access to the full range GSM technology is also used on other frequencies :- 4500,
800, 1800,1900 MHz
Maximum range is 35 kilometers due to timing requirements MS power is max 2 W for the handheld devices
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1. MS sends dialled number to BSS .2. BSS sends dialled number to
MSC.3. MSC checks VLR if MS is
allowed the requestedservice.MSC asks BSS to allocateresources for call.
5. MSC routes the call to GMSC.6. GMSC routes the call to local
exchange of called user.7. Answer back(ring back) tone isrouted from called user to MS byGMSC,MSC,BSS.
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1. Calling a GSMsubscribers.
2. Forwarding call toGMSC.
3. Signal Setup to HLR.
4. Request MSRN from VLR.
6. Forward responsibleMSC to GMSC.
7. Forward Call to currentMSC.
8. Get current status of MS.10. Paging of MS.12. MS answers.14. Security checks.16. Set up connection.
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Mobile telephony
Telemetry System
A utomatic meter reading
Value A
dded Services Other A pplications:-
Call waiting
Call divert
RoamingSMS
MMS
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