GSM Intro
Document Sample


GSM
Introduction
History of Mobile Communications
The beginnings: Radio transmission
„archaic mobile communication” • 1873 Maxwell’s theory of electromagnetic waves
• Visual transmission (smoke / light) • 1887 H. Hertz: experimental proof
• Audible transmission (drums, horns) • 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
Electronic communication: • 1907 1st mobile transmission: radio station - train
„terrestrial network”
• Telegraph
1st telegraph line 1843 Washington
• Telephone
P. Reis 1861
A.G. Bell 1876 World exhibition Philadelphia
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
450.4 – 457.6 / 460.4 – 467.6
GSM400 35 Rural environment
478.8 – 486 / 488.8 – 496
GSM900 890 – 915 / 935 – 960 124 Worldwide except
E-GSM 880 – 905 / 925 – 960 174 America
Worldwide except
GSM1800 1710 – 1785 / 1805 – 1880 374
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.