23-07-2012, 04:02 PM
MOBILE TELEPHONE SYSTEM
16361_MOBILE TELEPHONE SYSTEM.ppt (Size: 320.5 KB / Downloads: 36)
First-Generation Cellular
wireless communications used only analog signals.
voice is sent using frequency modulation (FM)
1G systems make use of a limited number of channels
4-KHz voice channel.
slow 20- to 30-kbps data rates.
LACK of capacity to support an authentication and encryption mechanism.
Second-Generation Cellular
wireless communications used both analog and digital signals.
Voice and data is sent.
2G systems enable enhanced services—such as short messaging, authentication, and phone software updates—to be accessed wirelessly.
GPRS 171.2kbps data rates.
GSM 474 kpbs data rates.
capacity to support an authentication and encryption mechanism
It is more secure as compare to 1G.
Third-Generation Cellular
wireless communications used both analog and digital signals.
Voice and data is sent.
3G systems enable enhanced services—to support multimedia applications.
UMTS 2mbps data rates.
capacity to support an authentication and encryption mechanism
It is more secure as compare to 1G and 2G.