Technologies
Part 1
F. Ricci
2010/2011
,Content
Wireless communication standards
Computer Networks
Reference model for a network architecture
Frequencies and regulations
Wireless communication technologies
Signals
Bandwidth limited signals
Signal modulation
Data transfer rate
Signal propagation
Most of the slides of this lecture come from prof. Jochen
Schiller’s didactical material for the book “Mobile
Communications”, Addison Wesley, 2003.
,Analogue vs. Digital
Analogue transmission of analogue data
The air pressure variations (analogue data) are
converted (microphone) into an electrical
analog signal in which either the instantaneous
voltage or current is directly proportional to
the instantaneous air pressure and then
transmitted (e.g., traditional phone or radio)
Analogue transmission of digital data
The electric analog signal is digitized, or
converted to a digital signal, through an
Analog-to-Digital converter and then
modulated into analogue signals and
trasmitted (e.g., digital phones as GSM).
, Wireless systems: overview
cordless wireless LAN
cellular phones satellites
phones
1980:
1981: CT0
NMT 450 1982:
1983: Inmarsat-A
AMPS 1984:
CT1
1986:
NMT 900 1987:
1988: CT1+
Inmarsat-C
1989:
CT 2
1991: 1991: 1991: 199x:
CDMA D-AMPS 1992: DECT proprietary
1992:
GSM-900 Inmarsat-B
1993: 1997:
Inmarsat-M
PDC HYPERLAN
1994: IEEE 802.11
GSM-1800 1998:
Iridium 1999:
802.11b, Bluetooth
2000: 2000:
analogue GPRS IEEE 802.11a
2001:
IMT-2000 (UMTS)
digital
200?:
Fourth Generation
(Internet based)
4G – fourth generation: when and how?