24-01-2013, 02:27 PM
GSM EVOLUTION
GSM EVOLUTION.ppt (Size: 630.5 KB / Downloads: 28)
Evolution of Technologies
First Generation Analog devices)
Second Generation Digital devices)
Third Generation: (Higher Bandwidth)
Fourth Generation: (Still under process)
First Generation (1G)
The first generation of wireless mobile communications was based on analog signaling.
Analog systems, implemented in North America, were known as Analog Mobile Phone Systems (AMPS)
Analog systems were primarily based on circuit-switched technology and designed for voice, not data.
Uses FDMA (Frequency Division Multiple Access) for access control.
Disadvantages of Analog Systems
Wastage of bandwidth
More noise
Consume More Power
Devices will be large in size.
Evolution of Technologies – Paging Systems
One way
Numbers or short text
Group messages possible
Less bandwidth – single burst of 30 bytes.
Modern day paging systems – 930-932 Mhz band
Evolution of Technologies – Analog Cellular Phones
1946- First Car based phone
Single large transmitter, single frequency, PTT
1960- IMTS – Improved Mobile Telephone System
High powered(200 watt) transmitter on hill top – Two frequencies
IMTS supported 23 channels 150-450Mhz
Impractical due to limited capacity
Second Generation (2G)
The second generation (2G) of the wireless mobile network was based on low-band digital data signaling.
The most popular 2G wireless technology is known as Global Systems for Mobile Communications (GSM). GSM systems, first implemented in 1991, are now operating in about 140 countries and territories around the world.
2G networks are designed for voice along with some limited data services like SMS etc.
Uses FDMA/TDMA for access control.
Services include
Global roaming
Superior voice quality and video conference
Data always add–on services (e-mail, personal organizer, etc.)
Information for web surfing, music, news, corporate intranet, transportation service etc.
Purchasing – on-line shopping / banking, ticketing, gambling, games, etc.