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A brief introduction GSM system
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Introduction to GSM system
Wade Hwang
Introduction to GSM systemIntroduction to GSM system
Introduction to GSM system
23/4/8Introduction to GSM system,
Wade Hwang2
Outline
Migration of GSM system
History of public wireless communication
History of GSM system
Working principle of GSM system
Concept of GSM system
Main components
Network structure
Important interfaces
Features of GSM system
Introduction to GSM system
CDMA
GSM
TDMA
PHS (IP-Based)
64 Kbps
GPRS
115 Kbps
CDMA 1xRTT
144 Kbps
EDGE
384 Kbps
cdma20001X-EV-DV
Over 2.4 Mbps
W-CDMA (UMTS)
Up to 2 Mbps
2G2.5G
2.75G 3G
1992 - 2000+2001+
2003+
1G
1984 - 1996+
2003 - 2004+
TACS
NMT
AMPS
GSM/GPRS
(Overlay) 115 Kbps
9.6 Kbps
9.6 Kbps
14.4 Kbps/ 64 Kbps
9.6 Kbps
PDC
Analog Voice
Digital Voice
Packet Data
IntermediateMultimedia
Multimedia
PHS
TD-SCDMA
2 Mbps?
9.6 Kbps
iDEN
(Overlay)
iDEN
Source: U.S. Bancorp Piper Jaffray
23/4/8Introduction to GSM system,
Wade Hwang3
History of public wireless communication
Introduction to GSM system
23/4/8Introduction to GSM system,
Wade Hwang4
1997
500
1000
2000
1000
2003
1500
400
2005
2000
2500
2007
3000
Global mobile-phone subscribers hit 2B (Oct 05)
3000Subscribers
(Millions)
UMTS 100 Million
History of public wireless communication
Introduction to GSM system
23/4/8Introduction to GSM system,
Wade Hwang5
History of GSM system
1982 1984 1985 1986 1987 1988 1989 1991 1992 1993 1994 2000 2001 2002 2003 2004 2006 2007 2008
Group Special Mobile (GSM) is formed by the
Confederation of European Posts and Telecommunications
(CEPT) to design a pan-European
mobile technology.
Trials of different digital radio transmission
schemes and different speech codecs in
several countries, with comparative evaluation by CEPT GSM in Paris.
Basic parameters of
the GSM standard agreed in February.
TDMA, RPE—LTP, GMSK
Completion of first set of
detailed GSM specifications
for infrastructure
tendering purposes.
first GSM call made
by Radiolinja in Finland.
Group Special Mobile defines
the GSM standard as the internationally
accepted digital cellular
telephony standard.
92 First international
roaming agreement
signed between Telecom
Finland and Vodafone (UK). First SMS sent.
02 95% of nations
worldwide have GSM networks.
06 GSM SURPASSES
TWO BILLION
CUSTOMERS.
03 First EDGE
networks go live.
First commercial
GPRS services
launched.
GSM surpasses 3
Billion connections
Introduction to GSM system
23/4/8Introduction to GSM system,
Wade Hwang6
Outline
Migration of GSM system
History of public wireless communication
History of GSM system
Working principle of GSM system
Concept of GSM system
Main components
Network structure
Important interfaces
Features of GSM system
Introduction to GSM system
23/4/8Introduction to GSM system,
Wade Hwang7
Concept of GSM system
GSM operation section (worldwide)
PLMN operation section (one or more in a country)
MSC operation section (one district controlled by a MSC)
LAI (Locating & paging district)
Cell (a specific area covered by a BTS)
Introduction to GSM system
23/4/8Introduction to GSM system,
Wade Hwang8
LAI (Location Area Identity)
Each location area of a public land mobile network (PLMN) has its own unique identifier which is known as Location Area Identity (LAI).
PLMN (Public Land Mobile Network)
A public land mobile network (PLMN) is a network that is established and operated by an administration or by a recognized operating agency (ROA) for the specific purpose of providing land mobile telecommunications services to the public. For example, in china, MNC (Mobile Network Code) of China Mobile’s GSM network is ‘00’, while China Unicom’s is ‘01’.
GSM operation section
Worldwide wireless communication network.
MSC operation section
One district controlled by a MSC
CELL
A specific area covered by a BTS
Concept of GSM system
Introduction to GSM system
23/4/8Introduction to GSM system,
Wade Hwang9
Main components
NSS (Network Switching Subsystem)
It carries out switching functions and manages the communications between mobile phones and the Public Switched Telephone Network.
BSS (Base Station Subsystem)
Responsible for handling traffic and signaling between a mobile phone and the network switching subsystem.
OMC (Operations and Maintenance Center)
The functional entity from which the network operator monitors and controls the system.
MS (Mobile Station)MS refers to the Mobile Phone. i.e. the handset held by the users in the mobile network.
Introduction to GSM system
23/4/8Introduction to GSM system,
Wade Hwang10
Network structure and main interfaces
Introduction to GSM system
23/4/8Introduction to GSM system,
Wade Hwang11
Important interfaces
Um - The air interface between the MS (Mobile Station) and the BTS.
Call control, measurement reporting, Handover, Power control, Authentication, Authorization, Location Update and so on.
Abis - The interface between the BTS and BSC.
BTS supervision and telecom signaling, and carries synchronization from the BSC to the BTS and MS.
A - The interface between the BSC and Mobile Switching Center.
Carrying Traffic channels
Ater - The interface between the BSC and Transcoder.
Gb - Connects the BSS to the Serving GPRS Support Node (SGSN) in the GPRS Core Network.
Introduction to GSM system
23/4/8Introduction to GSM system,
Wade Hwang12
Outline
Migration of GSM system
History of public wireless communication
History of GSM system
Working principle of GSM system
Concept of GSM system
Main components
Network structure
Important interfaces
Features of GSM system
Introduction to GSM system
23/4/8Introduction to GSM system,
Wade Hwang13
Features of GSM system
Spectrum efficiencyImproved spectrum efficiency due to new technologies utilized such as efficient modulator and demodulator, channel coding, Interleaving, equalization and Vocoder
System capacity3-5 times higher than TACS due to TDMA, half-speed Vocoder and other technologies adopted.
Voice qualitySame voice quality in the coverage where the signal strength is higher than threshold.
Open interfacesNot only open air interface but also open interfaces between system components, enables flexibility.
SecurityAuthentication, encryption and TMSI (temporary mobile subscriber identity).
RoamingSIM (subscriber identity module) and IMSI.
Introduction to GSM system
23/4/8Introduction to GSM system,
Wade Hwang14
Q&AThank you