GSM

Introduction

History of Mobile Communications

The beginnings:

„archaic mobile communication”• Visual transmission (smoke / light)• Audible transmission (drums, horns)

Electronic communication: „terrestrial network”• Telegraph

1st telegraph line 1843 Washington• Telephone

P. Reis 1861A.G. Bell 1876 World exhibition Philadelphia

Radio transmission• 1873 Maxwell’s theory of electromagnetic

waves• 1887 H. Hertz: experimental proof• 1895 Marconi: 1st wireless transmission• 1901 1st transatlantic transmission• 1903 Telefunken GmbH, AEG, Siemens +

Halske• 1906 1st speech and sound transmission• 1909 1st radio broadcast• 1907 1st mobile transmission: radio station -

train

Single Cell Systems• The first Mobile Telephone Service to

offer duplex connections comparable to fixed network based telephone services started in 1946 as a car phone service in St. Louis, Missouri.

• Comparable mobile telephone services appeared in post-war Europe some years later.

Cellular Mobile Radio Systems• The breakthrough in capacity was

achieved with the introduction of the Cellular Radio System in the late 1970s/early 1980s.

• The coverage of the supply area of a mobile communication operator involves many radio cells with cellular radio systems, in which the aforementioned limitation of the available HF frequency range is neatly circumvented through the repeated use of the HF channels.

Single Cell Systems – Cellular Systems

‘1G’ Cellular Mobile Radio Systems

• Information transmission of first generation cellular mobile radio system takes place via analogue radio interface.

• These systems were tested in many countries in the end of the 70s.

‘2G’ Cellular Mobile Radio Systems

• A further and very significant innovation in mobile radio communications took place with the introduction of the second generation cellular mobile radio system (e.g. GSM) in the early 90s.

• Transmission via radio interface is now digital.

‘2G’ Cellular Mobile Radio Systems

• Along with a significant improvement of transmission quality and expansion of services, there has been a considerable increase in capacity.

• The increase in subscribers led to more convenient, lighter and less expensive equipment with a wide range of possibilities for use.

Portable Mobile Equipment• Mobile phones were first introduced in

1988. The weight of the equipment decreased from 1 kg to less than a 100 g within few years.

• At the same time, mobility clearly improved despite decreasing weight owing to improvements in rechargeable batteries.

GSM

The GSM Recommendations• The GSM Standard is a consistent and

open standard for cellular mobile communication systems established by the ETSI.

• All aspects of the realization of the GSM Standard have been established in now more than 150 recommendations (technical specifications).

The GSM Recommendations• At the same time the Recommendations

are flexible enough for the different realizations of various vendors.

• The Recommendations are organized into 12 series according to different aspects.

• This structure reflects the structure of the PLMN (Public Land Mobile Network) system and its interfaces.

GSM Recommendation

The Evolutionary Concept• GSM Phase 1: (closed 1991) comprises

all of the most important prerequisites for digital information transmission. Speech transmission is of the greatest importance here. Data transmission is also defined (0.3 to 9.6 kbps). GSM Phase 1 comprises only a few supplementary services such as call forwarding and barring.

The Evolutionary Concept• GSM Phase 2: (closed 1995)

Supplementary Services comparable to ISDN were included in the standard. Technical improvements have been specified, e.g. the Half Rate Speech. In Phase 2, the decision on future downward-compatibility with older versions is of high importance.

The Evolutionary Concept• GSM Phase 2+: Individual topics are

discussed separately and the update is added to the GSM standard in Annual Releases. Main topics are new Supplementary Services as the ASCI services, the IN feature CAMEL and VHE are very important. Especially the introduction of features to achieve higher data rates, i.e. HSCSD, GPRS and EDGE has received much attention. GSM Phase 2+ thus paves the way to 3G (UMTS).

GSM Adaptations

Frequency Range [MHz]Useable HF channels

Application Area

GSM400450.4 – 457.6 / 460.4 – 467.6478.8 – 486 / 488.8 – 496

35 Rural environment

GSM900E-GSM

890 – 915 / 935 – 960880 – 905 / 925 – 960

124174

Worldwide except America

GSM1800 1710 – 1785 / 1805 – 1880 374Worldwide except America

GSM1900 1850 – 0910 / 1930 – 1990 299 America

GSM-R 876 – 880 / 921 – 925 19 Railway systems

PLMN - Public Land Mobile Network• A PLMN is a terrestrial mobile

communication network set up and run by public and private operators.

• It is used to provide public mobile communication services.