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8/9/2019 global syastem for mobile
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GLOBAL SYSTEM FOR
MOBILE
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HISTORY
The Europeans realized this early on,
and in 1982 the Conference of
European Posts and Telegraphs (CEPT)
formed a study group called the Groupe
Spcial Mobile (GSM) to study and
develop a pan-European public land
mobile system. The proposed systemhad to meet certain criteria:
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PURPOSES
Good subjective speech quality
Low terminal and service cost
Support for international roaming
Ability to support handheld terminals
Support for range of new services and
facilities
Spectral efficiency
ISDN compatibility
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ARCHITECTUREARCHITECTURE
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GSM network consists of the followingcomponents:
Mobile station. The GSM mobile station (ormobile phone) communicates with other parts ofthe system through the base-station system.
SIM:Subscriber Identification Module. A SIM cardcontains its unique serial number, internationalunique number of the mobile user (IMSI), securityauthentication and ciphering information,temporary information related to the local network
(also temporary local id that has been issued tothe user), a list of the services the user hasaccess to and two passwords (PIN for usual useand PUK for unlocking).
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GSM Base station system (BSS).
Base transceiver station (BTS). The basetransceiver station (BTS) handles the radiointerface to the mobile station. The basetransceiver station is the radio equipment(transceivers and antennas)
Base station controller (BSC). The BSCprovides the control functions and physicallinks between the MSC and BTS. Itprovides functions such as handover, cellconfiguration data and control of RF powerlevels in base transceiver stations. Anumber of BSCs are served by a MSC
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GSM Switching System
Mobile services switching center (MSC). TheMSC performs the telephony switching functionsof the system. It also performs such functions asnetwork interfacing, common channel signalling,
and others.
Home location register (HLR). The HLRdatabase is used for storage and managementof subscriptions. The home location register
stores permanent data about subscribers,including a subscriber's service profile, locationinformation, and activity status.
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Visitor location register (VLR). The VLR
database contains temporary informationabout subscribers that is needed by themobile services switching center (MSC) inorder to service visiting subscribers. When
a mobile station roams into a new mobileservices switching center (MSC) area, thevisitor location register (VLR) connected tothat MSC will request data about themobile station from the HLR, reducing the
need for interrogation of the home locationregister (HLR).
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Authentication center (AUC). The AUC
provides authentication and encryptionparameters that verify the user's identityand ensure the confidentiality of each call.The authentication center (AUC) alsoprotects network operators from fraud.
Equipment identity register (EIR). The EIRdatabase contains information on the
identity of mobile equipment to preventcalls from stolen, unauthorized or defectivemobile stations.
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CALL INPROGRESS-
STEPS 1) MS initialization after switched-on
2) Service request
3) Authentication and security 4) MS attach and detach
5) Location update
6) Outgoing voice call 7) Incoming voice call
8) SMS and special services
9) Call hand over
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GSM SPECIFICATIONS-1
RF SpectrumGSM 900
Mobile to BTS (uplink): 890-915 MhzBTS to Mobile(downlink):935-960 Mhz
GSM 1800Mobile to BTS (uplink): 1710-1785 MhzBTS to Mobile(downlink): 1805-1880Mhz
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GSM SPECIFICATIONS-2
Carrier Separation : 200 Khz
Duplex Separation : 45 Mhz No. of RF carriers : 124
Access Method : TDMA/FDMA
Modulation Method : GMSK Modulation data rate : 270.833 Kbps
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FDMA
Frequency Division Multiple
Access orFDMA is a channel access
method used in multiple-access
protocols as a channelization protocol.
FDMA gives users an individual
allocation of one or several frequency
bands, orchannels
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TDMA
Time division multiple access (TDMA)
is a channel access method for shared
medium networks. It allows several
users to share the samefrequencychannel by dividing the signal into
different time slots. The users transmit in
rapid succession, one after the other,each using his own time slot.
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EVOLUTION
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1-G
1G (or 1-G) refers to the first-generation
ofwireless telephone technology, mobile te
lecommunications.
The 1G system in GSM all power
allocation and handoffs strategies were
decided by MSC and then executed byBSC.
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2-G
GSM differs from its predecessors in that
both signaling and speech channels
are digital, and thus is considered a second
generation (2G) mobile phone system.
GSM also pioneered a low-cost (to the
network carrier) alternative to voice calls,the short message service (SMS, also called
"text messaging").
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The basic difference is that the
interfernce of MSC is reduced
as compared to 1-G the
power and handoff allocationdepends on THE BSC unless
in the case of roaming where
the MSCs are different.
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2.5-G
2.5 Generation ( Future of GSM)
HSCSD (High Speed ckt Switched
data)
Data rate : 76.8 Kbps (9.6 x 8 kbps)
GPRS (General Packet Radio service)
Data rate: 14.4 - 115.2 Kbps
EDGE (Enhanced data rate for GSM
Evolution)
Data rate: 547.2 Kbps (max)
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HSCSD-High-speed circuit-switched data
is the ability to use multiple time slots at
the same time. Using the maximum of fourtime slots, this can provide an increase in
maximum transfer rate of up to 57.6 kbit/s.
GPRS General Packet Radio Service
(GPRS) is a packet oriented Mobile Data
Service available to users of GlobalSystem for Mobile Communications
(GSM).
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GPRS can be used for services such
as WAP access, SMS, MMS, and forInternet communication services
such as email and World Wide Web
access. 2G cellular systemscombined with GPRS are often
described as "2.5G", that is, a
technology between the second (2G)
and third (3G) generations of mobile
telephony.
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EDGE Enhanced Data rates for
GSM Evolution (EDGE) is a digital
mobile phone technology that
allows increased data transmission
rates and improved data
transmission reliability. EDGE is
generally classified as 2.75G,
although it is part of the 3G
definition.
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3-G
3G is the third generation of telecommunicationhardware standards and general technology
for mobile networking.
3G networks enable network operators to offer
users a wider range of more advanced
services while achieving greater network
capacity through improved spectral efficiency.
Services include wide-area wireless voice
telephone, video calls, and broadband wireless
data, all in a mobile environment.
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Additional features also include HSPA data
transmission capabilities, which provides
users with data rates up to 14.4 Mbit/s on
the downlink and 5.8 Mbit/s on the uplink.
HSPA:High-Speed Packet Access (HSPA)is a 3G mobile telephony communications
protocol in the HSPA family, which allows
networks based on Universal Mobile
Telecommunications System (UMTS) to
increase data capacity and speed up
transfer rates.
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HSPA+ - HSPA+, also known as Evolved
HSPA is a wireless broadband standard
that provides HSPA data rates up to 42Mbit/s on the downlink and 22 Mbit/s on the
uplink .
UMTS Universal Mobile
Telecommunications System (UMTS) is one
of the third-generation (3G) cell phone
technologies, which is also being developedinto a 4G technology. It is closely related to
GSM/EDGE as it borrows and builds upon
concepts from GSM
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4-G
4G working group has defined the
following as objectives of the 4G
wireless communicationstandard:
A spectrally efficient system .
High network capacity: moresimultaneous users per cell.
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A nominal data rate of 100 Mbit/s
while the client physically moves athigh speeds relative to the station,
and 1 Gbit/s while client and station
are in relatively fixed positions as
defined by the ITU-R.
A data rate of at least 100 Mbit/s
between any two points in the world.
Smooth handoffacrossheterogeneous networks.
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Seamless connectivity and
global roaming across multiplenetworks.
High quality of service for next
generation multimedia support (real timeaudio, high speed data, HDTV video
content, mobile TV, etc).
Interoperability with existing wirelessstandards.
IP, packet switched network.
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LTE Long Term Evolution (LTE) is the
name given to a project to improve theUMTS mobile phone standard to cope
with future technology evolutions. Goals
include improving spectral efficiency,lowering costs, improving services,
making use of new spectrum and
reframed spectrum opportunities, and
better integration with other openstandards.
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CDMA
CDMA employs analog-to-digital conversion(ADC) in combination with spread
spectrum technology. Audio input is first
digitized into binary elements. The frequency of
the transmitted signal is then made to vary
according to a defined pattern (code), so it can
be intercepted only by a receiver whose
frequency response is programmed with thesame code, so it follows exactly along with the
transmitter frequency. There are trillions of
possible frequency-sequencing codes, which
enhances privacy and makes cloning difficult.
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CDMA CELL
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GSMCELL
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THANX