2. Mobile telecommunication evolution:
2.1 History of Mobile Cellular Systems:
Radiophones have a long and varied history . In 1960 world‘s first partly automatic car phone system A(MTA), was launched. MTA phones were composed of vaccum tubes and relays , and had weight of 40 kg. In 1962, a more modern version called mobile system B (MTB)was launched , which was a push - button telephone . In 1971 the MTD version was launched , opening for equipment and gaining commercial success .
The first commercially automated cellular network (the 1G generation ) was launched by NTT in 1979 . within five years , the NTT network became the first nation – wide 1G network . In 1981. This was followed by the simultaneous launch of the Nordic Mobile Telephone ( NMT ) system . then came the Advanced Mobile Phone system ( AMPS ) in 1982 .
The first “ modern“ network technology on digital 2G (second generation ) cellular technology was launched in 1991 on the GMS standard . In 2001 the first commercial launch of 3G ( third Generation ) on the WCDMA standard .
One of the newest 3G technologies to be implemented is High-Speed Downlink Packet Access ( HSDPA ) . It is an enhanced 3G ( third generation ) mobile telephone communications protocol in the High-Speed Packet Access (HSPA) family,also coined 3.5G, 3G+ or turbo 3G, which allows networks based on Universal Mobile Telecommunications system (UMTS) to have higher data transfer speeds and capacity.
2.2 Advanced Mobile Phone System--1G--(AMPS):
AMPS was invented by Bell Laps and first installed in the United States in 1982.It was also used in England, where it was called TACS, and in Japan, where it was called MCS-L1.
In first generation cellular technology, the system was fully analog, and is not in use today.
The features were:
- 12.5 MHz uplink.
- 12.5 MHz downlink.
- 416 channels, of 30 Hz each.
- Control and traffic channels.
- Every device has a hardware Numeric Assignment Module (NAM) used to identify the device.
- The Mobile Telephone Switching Office (MTSO) maintains a blacklist of NAMs.
- Devices in blacklist may not communicate in the network.
First Generation Cellular Mobile Radio Systems
Country
|
System
|
Frequency range
[ MHZ ]
|
Introduced in year
|
USA
|
AMPS
|
800
|
1979
|
Japan
|
NTT-MTS
|
800
|
1979
|
Sweden, Norway, Finland, Denmark
|
NMT
|
450 , 900
|
1981 – 86
|
Great Britain
|
TACS
|
900
|
1985
|
Germany
|
C450
|
450
|
1985
|
France
|
Radiocom2000
NMT
|
450
900
|
1985
1989
|
Italy
|
RTMS
TACS
|
450
900
|
1985
1990
|
2.3 Second Generation ( 2G ):
Afurther and very significant innovation in mobile radio communications took place with the introduction of the second generation cellular mobile system (e.g. GSM ).
2.4 Global System for Mobile communications (GSM)
2.4.1 History of GSM:
During the early 1980s, analog cellular telephone systems were experiencing rapid growth in Europe,particulary in the united kingdom,but also in france and germany. Each country developed its own system,which was incompatible with everyone else‘s in equipment and operation.
The Europeans realized this early on , and in 1982 the Conference of European Posts and Telegraphs (CEPT) formed a study group called the Group Special Mobile (GSM) to study and develop a pan-European public land mobile system. The proposed system had to meet certain criteria :
· Good subjective speech quality
· Low terminal and service cost
· Support for international roaming
· Ability to support handheld terminals
· Support for range of new services and facilities
· Spectral efficiency
· ISDN compatibility
Pan-European means European-wide. ISDN throughput at 64 kbs was never envisioned indeed, the highest rate a normal GSM network can achieve is 9.6 kbs.
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