01 Introduction to GSM_1

8/14/2019 01 Introduction to GSM_1

1/24

SYSTEM TRAINING

Introduction to GSMTraining Document

6-66861version 3.2

Nokia Networks Oy 1 (24)


2/24

Introduction to GSM

The information in this document is subject to change without notice and describes only theproduct defined in the introduction of this documentation. This document is intended for theuse of Nokia Networks' customers only for the purposes of the agreement under which thedocument is submitted, and no part of it may be reproduced or transmitted in any form ormeans without the prior written permission of Nokia Networks. The document has been

prepared to be used by professional and properly trained personnel, and the customerassumes full responsibility when using it. Nokia Networks welcomes customer comments aspart of the process of continuous development and improvement of the documentation.

The information or statements given in this document concerning the suitability, capacity, orperformance of the mentioned hardware or software products cannot be considered bindingbut shall be defined in the agreement made between Nokia Networks and the customer.However, Nokia Networks has made all reasonable efforts to ensure that the instructionscontained in the document are adequate and free of material errors and omissions. NokiaNetworks will, if necessary, explain issues which may not be covered by the document.

Nokia Networks' liability for any errors in the document is limited to the documentarycorrection of errors. Nokia Networks WILL NOT BE RESPONSIBLE IN ANY EVENT FORERRORS IN THIS DOCUMENT OR FOR ANY DAMAGES, INCIDENTAL ORCONSEQUENTIAL (INCLUDING MONETARY LOSSES), that might arise from the use of thisdocument or the information in it.

This document and the product it describes are considered protected by copyright accordingto the applicable laws.

NOKIA logo is a registered trademark of Nokia Corporation.

Other product names mentioned in this document may be trademarks of their respectivecompanies, and they are mentioned for identification purposes only.

Copyright Nokia Networks Oy 2008. All rights reserved.

2 (24) Nokia Networks Oy 6-66861version 3.2


3/24

Contents

Contents

1 Module objectives ..................................................................................5

2 Introduction ............................................................................................6 2.1 Mobile communications: Basic concepts..................................................6 2.2 Channel organisation in GSM/GPRS .....................................................11 2.2.1 Physical channel and TDMA frame ............................ ............................12 2.3 The Public Land Mobile Network............................................................13 2.4 GSM Specifications................................................................................14 2.5 GSM background and requirements ......................................................15 2.6 Advantages of GSM ...............................................................................16

3 Evolution of GSM .................................................................................18 3.1 The next step: UMTS .............................................................................21

4 Review questions.................................................................................23

6-66861version 3.2



4/24

Introduction to GSM

Preface

Already in the early days, GSM was superior to analogue mobile networks.When the standardisation work for GSM began in 1982, CEPT (ConfrenceEuropenne des Postes et Tlcommunications), could use experiences fromanalogue networks such as NMT (Nordic Mobile Telephone) and TACS (TotalAccess Communication System) to create a better digital network.

One main reason for the great success of GSM is that it was a European-wideproject already from the very beginning. Furthermore, the digital mobile systemenabled the supply of more sophisticated services, such as SMS (Short MessageService), and bearer services for data transmission.

Thanks to the global popularity of GSM, we may now use our mobile stations inmore than 130 countries, a fact that has made both business and leisuretravellers' lives much more convenient.

Still today, standardisation continues to specify new features for GSMnetworks. This ambitious work creates opportunities for the operators todifferentiate themselves in a competitive environment. Today, we are more andmore focusing on faster wireless transmission and the introduction of packetswitched data.

The 3G (Third Generation) network technologies are also already specified andin many parts of the world operational. The 3G version in Europe, is namedUMTS (Universal Mobile Telecommunications System). Its air interface will bebased on WCDMA (Wideband Code Division Multiple Access) transmission.3G networks provide substantially higher capacities than 2G.

This technically oriented material will help you to better understand the windowof opportunities today and in the near future. Your active participation will bean essential ingredient for a successful and fulfilling training.



5/24

Module objectives

1 Module objectivesAfter completing this module, the participant should be able to:

Name the key terms in mobile communications

List the main improvements from 1G to 2G mobile communicationssystems

Identify five events in the GSM evolution and connect each with thecorrect year

without using any references.

6-66861version 3.2



6/24

Introduction to GSM

2 Introduction

2.1 Mobile communications: Basic concepts

From ancient to modern times, mankind has been looking for means of longdistance communications. For centuries, letters proofed to be the most reliableway to transmit information. Fire, flags, horns, etc. were used to transmitinformation faster.Technical improvements in the 19 th century simplified long distancecommunications: Telegraphy, and later on telephony. Both techniques werewireline.

In 1873, J. C. Maxwell laid the foundation of the electro-magnetic theory bysummarising empirical results in four equations, which are still valid today. Itwould however be several decades before Marconi made economic use of thistheory by developing devices for wireless transmission of Morse signals (about1895). Already 6 years later, the first transatlantic wireless transmission of Morse signals took place. Voice was transmitted the first time in 1906 (R.Fesseden), and one of the first radio broadcast transmission 1909 in New York.

DuplexSimplex

o n e - w a y

two-way

Figure 1. Transmission

The economically most successful wireless application in the first half of the20 th century was radio broadcast. There is one transmitter, the so-called radiostation. Information, such as news, music, etc. is transmitted from the radiostation to the receiver equipment, the radio device. This type of one-waytransmission is called simplex transmission . The transmission takes place onlyin one direction, from the transmitter to the receiver. When we take a human



7/24

Introduction

conversation, a technical solution is required, where the information flow cantake place in two directions. This type of transmission is called duplextransmission . Walky-talky was already available the early 30ies. This systemalready allowed a transmission of user data in two directions, but there was alimitation: The users were not allowed to transmit at the same time. In otherwords, you could only receive or transmit user information. This type of transmission is therefore often called semi-duplex transmission. For telephonyservices, a technical solutions is required, where subscribers have theimpression, that they can speak (transmit) and hear (receive) simultaneously.This type of transmission solution is regarded as full duplex transmission.

The first commercial wireless car phone telephony service started in the late1940 in St. Louise, Missouri (USA). It was a car phone service, because at thattime, the mobile phone equipment was bulky and heavy. Actually, in the start-up, it filled the whole back of the car. But it was a real full duplex transmissionsolution. In the 50ies, several vehicle radio systems were also installed in

Europe. These systems are nowadays called single cell systems . The user datatransmission takes place between the mobile phone and the base station (BS). A base station transmits and receives user data. While a mobile phone is onlyresponsible for its users data transmission and reception, a base station iscapable to handle the calls of several subscribers simultaneously. Thetransmission of user data from the base station to the mobile phone is calleddownlink (DL), the transmission from the mobile phone to the base stationuplink (UL) direction. The area, where the wireless transmission betweenmobile phones and the base station can take place, is the base stations supplyarea, called cell .

cell = supply area

BasestationDownlink (DL)

Uplink(UL)

Figure 2. Single Cell System

Single cell systems are quite limited. The more and more distant the subscriberis from the base station, the lower the quality of the radio link. If the subscriberis leaving the supply area of the cell, no communication is possible any more. In

6-66861version 3.2



8/24

Introduction to GSM

other words, the mobile communication service was only available within thecell. In order to overcome this limitation, cellular systems were introduced. Acellular mobile communication system consists of several cells, which canoverlap. By doing so, a whole geographical area can be supported with themobile communication service.

Figure 3. Cellular System

But what happens, when a subscriber moves during a call from one cell toanother cell? It would be very annoying, if the call is dropped. If the subscriberis leaving a cell, and in parallel is entering a new cell, then the system makesnew radio resources available in the neighbouring cell, and then the call ishanded over from on cell to the next one. By doing so, service continuation isguaranteed, even when the subscriber is moving. The process is calledhandover (HO) .

Arles

Nimes

Avignon

Salon- de-Provence

Cavaillon

Orange

Carpentras

Aix-en-Provence

Coverage

Arles

Nimes

Avignon

Salon- de-Provence

Cavaillon

Orange

Carpentras

Arles

Nimes

Avignon

Salon- de-Provence

Cavaillon

Orange

Carpentras

Aix-en-Provence

Coverage



9/24

Introduction

Mobile phone is active,e.g. a call takes place

Service continuationwithout interruption

Figure 4. Handover

A handover takes place during a call, i.e. when the mobile phone is in active(dedicated) mode. A mobile phone can also be in idle mode. In this case, themobile phone is switched on, but no resources are allocated to it to allow userdata transmission. In this mode, the mobile phone is still listening toinformation, broadcasted by the base station. Why?Imagine, there is a mobile terminated call. The mobile phone is then paged in

the cell. This means the phone receives information that there is a mobileterminated call. A cellular system may consist of hundreds of cells. If themobile network does not know, in which cell the mobile phone is located, itmust be paged in all of them. To reduce load on networks, paging in is done insmall parts of a mobile an operators network. Mobile network operators groupcells in administrative units called location areas (LA) . A mobile phone ispaged in only one location area.

But how does the cellular system know, in which location area the mobilephone is located? And how does the mobile phone know? In every cell, systeminformation is continuously transmitted. The system information includes thelocation area information. In the idle mode, the mobile phone is listening to thissystem information. If the subscriber moves hereby from one cell to the nextcell, and the new cell belongs to the same location area, the mobile stays idle. If the new cell belongs to a new location area, then the mobile phone has tobecome active. It starts a communication with the network, informing it about itnew location. This is stored in databases within the mobile network, and if thereis a mobile terminated call, the network knows where to page the subscriber.The process, where the mobile phone informs the network about its newlocation is called Location Update Procedure (LUP).

6-66861version 3.2



10/24

Introduction to GSM

Location Area 1

Location Area 2

Location Area 3

no Location Update

Location Update

Location Area=

registrationarea of onesubscriber

Figure 5. Location Update and Paging

With the introduction of cellular mobile communication systems, we refer togenerations. First generation mobile communication systems are

TACS (Total Access Communications System)

NMT (Nordic Mobile Telephony)

AMPS (Advanced Mobile Phone Service)

C450

etc.

All of them were commercially launched in the 80s of the last century.The 1 st generation mobile communication systems often offered national widecoverage. But there were limitations:Most of them did not support roaming. Roaming is the ability to use an otheroperators network infrastructure. International roaming is the ability to go evento another country and use the local operators infrastructure.



11/24

Introduction

Roaming=

ability to usedifferent

operatorsinfrastructure

GSM subscriber

from Spain

can use GSM networkin Australia, givenroaming agreementbetween home operatorand visited operator

Example:

Figure 6. Roaming

Most 1 st generation mobile communication systems only support speechtransmission, but not data transmission, such as fax. Supplementary services,well known from ISDN, were not available, such as number indication and callforwarding, when busy. The transmission takes place unprotected via the radiointerface as a consequence, eavesdropping is possible. Finally, mobilecommunication started to become a mass market. And the radio interface is themain bottleneck in terms of capacity. Improved solutions were urgentlyrequired. This led to the inauguration of the 2 nd generation mobilecommunication systems, one of which is GSM.

2.2 Channel organisation in GSM/GPRS

In GSM 900, 25 MHz spectrum has been frequency divided into 124 bands,each having a bandwidth of 200 kHz. On each of the 200 kHz bands a carriercan be transmitted at the centre frequency of the band. The carriers are thusfrequency division multiplexed.

6-66861version 3.2



12/24

Introduction to GSM

UPLINK DOWNLINK

GSM900: 890 MHz - 915 MHz 935 MHz - 960 MHz

GSM1800: 1710 MHz - 1785 MHz 1805 MHz - 1880 MHz

1 2 3 ...

Channel 1 - 1241 - 374

200 kHz

1 2 3 ...

Duplex frequency 45 MHz / 95 MHz

guard band

Figure 7. FDD and FDMA organisation in GSM

Each carrier is further time divided into timeslots (TSL) and each timeslot isreferred to as a physical channel . It is possible to share a physical channelamongst many processes or users. This sharing is referred to as logicalchannels .

2.2.1 Physical channel and TDMA frame

TDMA frame= 8 timeslots

01

23

4 5

76

01

23

45

76

01

23

45

200 kHz

Physcial channel,e.g. allocated to one

subscriber with FR voice &no frequency hopping

frequency

t i m e

TDMA frame

Figure 8. TDMA frame and physical channel



13/24

Introduction

Time Division Multiple Access (TDMA), is a method of sharing a resource (inthis case a radio frequency) between multiple users, by allocating a specifictime (known as the time slot ) for each user. This is in contrast to the analoguemobile systems where one radio frequency is used by a single user for theduration of the conversation. In Time Division Multiple Access (TDMA)systems each user either receives or transmits bursts of information only in theallocated time slot. These time slots are allocated for speech only when a userhas set up the call. Some timeslots are, however, used to provide signalling andlocation updates etc. between calls. The main benefit of the time based systemis higher capacity than in earlier systems.

In GSM, a TDMA frame is defined as a grouping of TSLs which are numbered0 to 7 as shown above. It has duration of 4.615ms (8 x 577 s).

TDMA frames are transmitted one after another. Every TDMA frame isallocated a frame number .

Um is the acronym for the GSM radio interface. It is an open interface, i.e. it isvery accurately specified and thus vendor independent. A subscriber can usemobile phones from any manufacturer without bothering about the operatorsGSM infrastructure and supplier, as long as the network elements are compliantwith the GSM specifications.

2.3 The Public Land Mobile Network

A mobile operators network is called Public Land Mobile Network. It is

subdivided into three parts:

Base Station Subsystem (BSS)

Network Switching Subsystem (NSS)

Network Management Subsystem (NMS)

The Network Switching Subsystem is responsible for switching, mobilitymanagement, and traffic element, i.e. that here network elements such asexchanges and data bases can be found. The exchanges are responsible forswitching, while the data bases are used to keep track of the current location of the subscriber and his mobile phone. Mobile subscribers can be anywhereworldwide. This creates a challenge when there is a call since even in a mobilenetwork a subscribers location must be known before a call can be set up.There are millions of cells, were the subscriber and his mobile phone can belocated. The NSS databases serve to locate mobile subscribers when needed.

The Base Station Subsystem is responsible for the link between a mobile phoneand a network exchange. The radio interface must contain many functions toenable mobile calls. For example user data must be protected by ciphering of user data in the base station and the mobile phone. The transmission must bereliable which invokes error protection methods. If a mobile subscriber wants to

6-66861version 3.2



14/24

Introduction to GSM

make a call, physical resources must be allocated to the user in a controlledmanner. The tasks of the BSS can be summarised under the key terms RadioResource Management (RRM) and Radio Link Management (RLM).

The Network Management System supports the operator in remote network supervision. Fault, configuration, and performance management are centraltasks performed within the NMS.

Very important open interfaces are the Um interface and the A-interface. Openinterfaces guarantee interworking of network elements from different vendors.An operator may select the NSS from one vendor, the BSS from a secondvendor and the subscriber may use any vendors mobile phone.

A

NMSNMS

NSSNSSBSSBSSO&M

Air

MS

Network SwitchingSubsystem

Switching Mobili ty Management Connection Management Charging

Base Stat ion Subsystem Radio Resource Management Radio Link Management Network Management System

Fault Management Configuration Management Performance Management

Figure 9. The Public Land Mobile Network (PLMN)

2.4 GSM Specifications

One reason for the major success of GSM is, that it is very accuratelystandardised. The standard is open, i.e. it is available to everyone. The EuropeanStandards Telecommunications Institute (ETSI) is responsible for the GSM

standards. The GSM technical specifications are grouped in this way:

01General Description of a GSM PLMN02 Services03 Network Functions04 MS - BSS Interface05 Radio Path06 Speech Processing Functions07 Terminal Adaptation Functions



15/24

Introduction

08 BSS - MSC Interface09 Network Inter Working[10 Service Inter Working]11 Type Approval Procedures12 Operation and Maintenance

2.5 GSM background and requirements

At the beginning of the 1980s a problem was that the European countries wereusing many different, incompatible mobile phone systems. These systems arereferred to as 1G (first generation) systems. In Europe, the most common 1Gsystem was NMT (Nordic Mobile Telephone) and TACS (Total AccessCommunications System). In the United States, as well as in other Americancountries, AMPS (Advanced Mobile Phone System) was, and still is, a widelyestablished system.

With the passage of time, the need for telecommunication services wasremarkably increased. Due to this, CEPT (Confrence Europenne des Postes etTlcommunications) founded a group to specify a common mobile system forWestern Europe. This group was named Groupe Spciale Mobile and thesystem name GSM arose.

This abbreviation has since been interpreted in other ways, but the mostcommon expression nowadays is Global System for Mobile communications.GSM is a 2G (second generation) system

Figure 10. GSM Global System for Mobile communications

6-66861version 3.2



16/24

Introduction to GSM

At the beginning of the 1990s, the lack of a common mobile system was seen tobe a general, worldwide problem. For this reason the GSM system has nowspread also to the Eastern European countries, Africa, Asia and Australia. TheUSA, South America in general, and Japan has made a decision to adopt othertypes of mobile systems, which are not compatible with GSM. However, in theUSA the Personal Communication System (PCS) has been adopted, which usesGSM technology with a few variations.

During the time the GSM system was being specified, nationaltelecommunication markets were deregulated. Requirements for openness andcompetition were built into the specifications as follows:

There should be several network operators in each country. This wouldlead to competition in tariffs and service provisioning and it would ensurethe rapid expansion of the GSM system. The prices of the equipmentwould fall and the users would find the cost of calls reducing.

The GSM system must be an open system, meaning that it should containwell-defined interfaces between different system parts. This enables theequipment from several manufacturers to coexist and hence improves thecost efficiency of the system from the operator's point of view.

GSM networks must be built without causing any major changes to thealready existing Public Switched Telephone Networks (PSTN).

In addition to the commercial demands, some other objectives were defined:

The system must be Pan European.

The system must maintain a good speech quality.

The system must use radio frequencies as efficiently as possible.

The system must have high/adequate capacity.

The system must be ISDN compatible (Integrated Services DigitalNetwork) and compatible with other data communication specifications.

The system must maintain good security both for subscriber andtransmitted information.

2.6 Advantages of GSM

Due to the requirements set for the GSM system, many advantages will beachieved. These advantages can be summarised as follows:

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.



17/24

Introduction

With ISDN compatibility, new services are offered.

International roaming is technically possible within all countries using theGSM system.

The large market increases competition and lowers the prices both forinvestments and usage.

6-66861version 3.2



18/24

Introduction to GSM

3 Evolution of GSMOne key factor for the success of GSM was that the standardisation work wasnot completed after 1989. It was initially decided that GSM would evolve overtime. With improvements in computing and radio access technology, GSM willoffer continuous improvement and more services. In 1995 the Phase 2 recommendations were frozen. The GSM 900 and GSM 1800 specificationswere merged and additional supplementary services were defined, the shortmessage service was improved and improvements in radio access and SIMcards were introduced.

After the Phase 2 recommendations, GSM continues to evolve at full speed.Many new features are being introduced to GSM and the number of improvements is so large that together they are called "Phase 2+" features.These Phase 2+ features are frozen at regular intervals under what are known as

"Releases".The following list highlights some important years in the short history of GSM:

1982 CEPT initiated a new cellular system. The European Commission(EC) issued a directive that required member states to reservefrequencies in the 900 MHz band for GSM to allow for roaming.

1986 CEPT tested eight experimental systems in Paris.

1987 Memorandum of Understanding (MoU). Allocation of the frequencies:- 890 - 915 MHz uplink (from mobile to base station)- 935 - 960 MHz downlink (from base station to mobile)

1988 European Telecommunications Standard Institute (ETSI) was created.ETSI includes members from administrations, industry, and usergroups.

1989 Final recommendations and specifications for GSM Phase 1.

1990 Validation systems implemented and the first GSM World Congressin Rome with 650 participants.

1991 First official call in the world with GSM on 1 st July.

1992 World's first GSM network launched in Finland. The first roamingagreement was made. By December there were 13 networks operatingin 7 areas. Australian operators were the first non-European

signatories of the GSM MoU. New frequency allocation for GSM1800 (DCS 1800).- 1710 - 1785 MHz (uplink)- 1805 - 1880 MHz (downlink)

1993 GSM demonstrated for the first time in Africa at Telkom '93 in CapeTown. Roaming agreements between several operators. By December1993 there were 32 GSM networks operating in 18 areas.



19/24

Evolution of GSM

1994 The first GSM network in Africa was launched in South Africa. TheGSM Phase 2 data/fax bearer services were launched. By December1994 there were 69 GSM networks in operation.

1995 There were 117 GSM networks operating around the world. Fax, data,and SMS roaming was implemented. The GSM phase 2standardisation was completed, including adaptation for GSM 1900(PCS 1900). The first GSM 1900 network was implemented in theUSA. Telecom '95 was held in Geneva where Nokia demonstrated33.6 Kbits/s multimedia data via GSM.

1996 By December there were 120 networks operating. The 8K SIM waslaunched in addition to prepaid GSM SIM cards.

1998 HSCSD (High Speed Circuit Switched Data) trials in Singapore. Over2 million GSM 1900 users in the USA and a total of 120 million GSM900/1800/1900 users worldwide.

1999 The first mobile data call using GPRS (General Packet Radio Service)in a live network was made. The first HSCSD (High Speed CircuitSwitched Data) networks are launched. In December, the 271 millionsubscribers sent over 3 billion short messages (G-mails) worldwide. InJanuary 2000 there were 359 GSM networks operating in 132different countries.GSM 850 support: UL: 824 849 MHz and DL: 869 894 MHz (forNorth America).Location Based Services (LBS) services standardised. LBS can becombined with GPS (Global Positioning System), so that a subscribercan determine his geographical location extremely accurately.

Operator Specific Access (OSA) specified: with it, open applicationprogramming interfaces between an operators network infrastructureand external VASP are given. It allows service provision fromexternal VASP without knowledge of the operators internal network infrastructure.The 3G mobile communications system UMTS was specified inDecember. It is based on the GSM standards to allow a smoothevolution from the 2 nd generation to the 3 rd generation. This ought toguarantee an investment protection for GSM operators.

2000 The first GPRS network is launched.Second release of UMTS delayed to year 2001

2001 The Multimedia Messaging Service (MMS) was standardised.GSM 700 supported; UL: 747 762 MHz and DL: 777 792 MHzUMTS and GSM standardised at 3GPP; UMTS/GSM Rel. 4standardised

2002 UMTS/GSM Rel. 5 standardised (IMS) was standardised forGSM/GPRS and UMTS.More than 40 MMS services have been launched this year in countriessuch as Czech Republic, Hungary, Germany, and Hong Kong. MMS(Multimedia Messaging Service) enables personalised multimedia

6-66861version 3.2



20/24

Introduction to GSM

messages, which can include images, texts, photos, etc. It is forecastedby the analyst Foster, that in the year 2007, that MMS will account formore than 30% of the mobile messaging revues. MMS is especiallyflexible, when transmitted via the GPRS infrastructure.At the end of the year 2002, more that 120 operators are commerciallyoffering GPRS, and more than 40 operators are testing GPRS orbuilding up a GPRS infrastructure.Smartphones are under development for GSM/GPRS and UMTS toallow a wide range of mobile services, such as mobile Internet, mobilegambling, enhanced LDAs, video messaging, agnostic services, etc.

2003 First commercial starts of UMTS network operators in Europe.

2004 More than one billion people, almost one in six of the worldspopulation, are now using GSM mobile phones. More than 200countries and territories has adopted GSM and it has become a trulyglobal standard for mobile communications. As the choice of 80 percent of all new mobile customers, GSM has driven wireless take-up tothe extent that mobile phones now outnumber fixed telephone linesglobally

0

200

400

600

800

1000

1200

1400

Dec 97 Dec 98 Dec 99 Dec 00 Dec 01 Dec 02 Dec 03 Dec 04 Dec 05

Figure 11. GSM customers worldwide and customer forecast (Dec 2002)



21/24

Evolution of GSM

0

5

10

15

20

25

30

J a n 0 0

A p r 0

0 J u l

0 0

O k t 0

0 J a n

0 1

A p r 0

1 J u l

0 1

O k t 0

1 J a n

0 2

A p r 0

2 J u l

0 2

Billion

Jan 00 Jul 00 Jul 01 Jul 02Jan 00 Jan 02

Source: GSM Association

Figure 12. SMS growth during the last three years

In some European countries, SMS has reached saturation, e.g. it only slightlygrowing on a very high level. It is assumed, that MMS will substitute SMS overthe next years.

3.1 The next step: UMTSThe third generation solution UMTS, is expected to complete the globalisationprocess of the mobile communication. UMTS will mostly be based on GSMtechnical solutions due to two reasons. Firstly, the GSM technology dominatesthe market, and secondly, great investments made to GSM should be utilised asmuch as possible. Based on this, the specification bodies created a vision abouthow mobile telecommunication will develop within the next decade. Throughthis vision, some requirements for 3G were short-listed as follows:

The system to be developed must be fully specified (like GSM). Thespecifications generated should be valid worldwide.

The system must bring clear added value when comparing to the GSM inall aspects. However, in the beginning phase(s) the 3G system must bebackward compatible at least with GSM and ISDN.

Multimedia and all of its components must be supported throughout thesystem.

The radio access of the 3G must be generic. The services for the end-users must be independent of the access: radio access and the network infrastructure must not limit the services to be generated. That is, the

6-66861version 3.2



22/24

Introduction to GSM

technology platform is one issue and the services using the platformanother issue.

The 3G system is expected to run a very high data rate that will allow us to have

multimedia traffic through the wireless network. Enhanced packet switchingand routing techniques are to be deployed to support video traffic and otherreal-time traffic in the 3G wireless network. The 3G system will use theBroadband Integrated Services Digital Network (B-ISDN) to provide dataservices between the existing data networks and the wireless network.

The Global 3G Partnership Project (3GPP) incorporating many organisations(ITU-T, ETSI, ARIB and ANSI) is developing standards for the 3G systems.These documents can be viewed at www.3gpp.org .

http://www.3gpp.org/http://www.3gpp.org/


23/24

Review questions

4 Review questionsIn the following questions, please select one alternative that you think is thebest answer for the particular question . There may not be a perfect answer,select the one you think is the most correct.

1. Name advantages of cellular systems to single cell systems.

2. Explain the difference between handover and location update procedure.

3. Which of the following is a requirement for the GSM specifications?

a. The system must be compatible with existing mobile standards.

b. The system must be standardised globally.

c. The system must be built without causing any major changes in theexisting Public Switched Telephone Networks (PSTN).

d. All of the above.

4. Which two statements in the following are generally seen as advantagesof GSM over analogue networks?

a. Data transmission is supported in the whole GSM network.

b. It is only possible to use an analogue mobile telephone in the ownnetwork.

c. GSM mobile stations can be used in other digital mobile networks,for instance in NMT and TACS networks.

d. GSM is a more secure system than analogue systems with respectto subscriber information and transmission.

6-66861version 3.2



24/24

Introduction to GSM

5. Match the year in the left-hand column with the corresponding significantGSM event in the middle column.

Year Event Correct year

1982 Allocation of GSM frequencies

2000 Experimental test in Paris

1995 Frequency allocation for GSM 1800

1989 First official GSM call in the world

1991 Initiation of a new system

1987 ETSI begins the specification work for 3G/UMTS

1992 Final recommendations Phase 1

1999 Phase 2 recommendations frozen1986 Total GSM subscribers exceeds 300 million

24 (24) Nokia Networks Oy 6 66861

Documents

01 Introduction to GSM_1