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GSM

Introduction



History of Mobile Communications

The beg innings:

Åarchaic mobile communicationµ

� Visual tr ansmission ( smok e / light)

� Audible tr ansmission (drums, horns)

Electronic communication:

Åt err estrial networkµ

� Teleg r aph1st t eleg r aph line 1843 Washing ton

� Telephone

P. Reis 1861

A.G. Bell 1876 World exhibition Philadelphia

Radio tr ansmission

� 1873 Max well·s t heory of electromag netic waves

� 1887 H. Hertz: experiment al proof

� 1895 Marconi: 1st wir eless tr ansmission

� 1901 1st tr ansatlantic tr ansmission� 1903 Telefunk en GmbH, AEG, Siemens + Halsk e

� 1906 1st speech and sound tr ansmission

� 1909 1st r adio broadcast

� 1907 1st mobile tr ansmission: r adio st ation - tr ain



Single Cell Systems

� The fir st Mobile Telephone Ser v ice to off er duplex

connections compar able to fixed network based

t elephone ser v ices st art ed in 1946 as a car phoneser v ice in St . Louis, Missouri.

� Compar able mobile t elephone ser v ices appear ed in

post -war Europe some y ear s lat er .



Single Cell Systems ² Cellular Systems



¶1G· Cellular Mobile Radio Systems

� Infor mation tr ansmission of fir st gener ation cellular

mobile r adio sy st em t ak es place v ia analog ue r adio

int erf ace.

� These sy st ems wer e t est ed in many countries in t he end

of t he 70s.




� A furt her and very sig nificant innovation in mobile r adio

communications took place wit h t he introduction of t he

second gener ation cellular mobile r adio sy st em ( e.g.

GSM) in t he early 90s.

� T r ansmission v ia r adio int erf ace is now dig it al.




� Along wit h a sig nificant improvement of tr ansmission

quality and expansion of ser v ices, t her e has been a

consider able incr ease in capacity .

� The incr ease in subscriber s led to mor e convenient ,

light er and less expensive equipment wit h a wide r ange

of possibilities for use.



Portable Mobile Equipment

� Mobile phones wer e fir st introduced in 1988. The

weight of t he equipment decr eased from 1 k g to less

t han a 100 g wit hin f ew y ear s.

� At t he same time, mobility clearly improved despit e

decr easing weight owing to improvement s in

r echar geable batt eries.



GSM



The GSM Recommendations

� The GSM St andard is a consist ent and open st andard

for cellular mobile communication sy st ems est ablished

by t he ETSI.

� All aspect s of t he r ealization of t he GSM St andard have

been est ablished in now mor e t han 150

r ecommendations (t echnical specifications).



The GSM Recommendations

� At t he same time t he Recommendations ar e flex ible

enough for t he diff er ent r ealizations of various vendor s.

� The Recommendations ar e or ganized into 12 seriesaccording to diff er ent aspect s.

� This structur e r eflect s t he structur e of t he PLMN ( Public

Land Mobile Network) sy st em and it s int erf aces.



GSM Recommendation



The Evolutionary Concept

� GSM Phase 1: (closed 1991) comprises all of t he most

import ant pr er equisit es for dig it al infor mation

tr ansmission. Speech tr ansmission is of t he g r eat est

import ance her e. Dat a tr ansmission is also defined ( 0.3

to 9.6 k bps). GSM Phase 1 comprises only a f ew

supplement ary ser v ices such as call forwarding and

barring.




� GSM Phase 2: (closed 1995) Supplement ary Ser v ices

compar able to ISDN wer e included in t he st andard.

Technical improvement s have been specified, e.g. t he

Half Rat e Speech. In Phase 2, t he decision on futur e

downward-compatibility wit h older ver sions is of high

import ance.




� GSM Phase 2+: Indiv idual topics ar e discussed separ at ely

and t he updat e is added to t he GSM st andard in Annual

Releases. Main topics ar e new Supplement ary Ser v ices as

t he ASCI ser v ices, t he IN f eatur e CAMEL and VHE ar e very import ant . Especially t he introduction of f eatur es to

achieve higher dat a r at es, i.e. HSCSD, GPRS and EDGE has

r eceived much att ention. GSM Phase 2+ t hus paves t he

way to 3G (UMTS).



GSM Adaptations

F r equency Range [MHz] Useable HF channels Application Ar ea

GSM400450.4 ² 457.6 / 460.4 ² 467.6

478.8 ² 486 / 488.8 ² 49635 Rur al env ironment

GSM900

E-GSM

890 ² 915 / 935 ² 960

880 ² 905 / 925 ² 960

124

174

Worldwide ex cept

America

GSM1800 1710 ² 1785 / 1805 ² 1880 374Worldwide ex cept

America

GSM1900 1850 ² 0910 / 1930 ² 1990 299 America

GSM-R 876 ² 880 / 921 ² 925 19 Railway sy st ems



PLMN - Public Land Mobile Network

� A PLMN is a t err estrial mobile communication network

set up and run by public and privat e oper ator s.

� It is used to prov ide public mobile communication

ser v ices.

mhhi 01 01 gsm intro bg

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