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1.3 WIRELESS TECHNOLOGIES
Wireless networking technologies range from global voice and data networks to infrared light and radio frequency technologies optimized for short-range wireless connections. Devices commonly used for wireless networking include portable computers, desktop computers, handheld computers, PDAs, cellular phones, pen-based computers and pagers. Wireless technologies have evolved substantially over the past few years and, depending on their range, can be classified in different ways.
WIRELESS TECHNOLOGIES Wireless Wide Area Network
This network is designed to enable users to access the Internet via a wireless wide area network (WWAN) access card and a PDA or laptop. Data speeds are very fast compared with the data rates of mobile telecommunications technology, and their range is also extensive. Cellular and mobile networks based on CDMA and GSM are good examples of WWAN.
Wireless Local Area Network
This network is designed to enable users to access the Internet in localized hotspots via a wireless local area network (WLAN) access card and a PDA or laptop. While data speeds are relatively fast compared with the data rates of mobile telecommunication technology, their range is limited. Among the various WLAN solutions, Wi-Fi is the most widespread and popular.
Wireless Personal Area Network
This network is designed to enable the users to access the Internet via a wireless personal area network (WPAN) access card and a PDA or laptop. While data speeds are very fast compared with the data rates of mobile telecommunications technology, their range is very limited.
Wireless Region Area Network
This network is designed to enable the users to access the Internet and multimedia streaming services via a wireless region area network (WRAN). Data speeds are very fast compared with the data rates of mobile telecommunication technology as well as other wireless network, and their range is also extensive. The specific charter of the WRAN working group is to ‘develop a standard for a cognitive radio-based air interface for use by license-exempt devices on a non-interfering basis in spectrum that is allocated to the TV Broadcast Service’. WRAN, which is presently in its infant stage, is the most recent addition to a growing list of wireless access network acronyms defined by coverage area.
Fixed Local area Wide area
Figure 1.6 Wireless technologies, bandwidth versus distance
We will deal with two types of wireless networks, WLAN and WWAN (Figure 1.6).
1.4 THIRD-GENERATION MOBILE SYSTEMS
The remarkable growth of cellular mobile telephony as well as the need for wireless data services promises an impressive potential for a market that combines high speed with the convenience of mobile technology. Universal Mobile Telecoms Service (UMTS) Generation 3 will offer users an alternative with high-speed access, allowing connectivity from any location on the planet (Table 1.1).
First-generation Mobile Systems
The first wireless generation introduced analogue systems transmitting over radio frequencies, used primarily for voice. The operation of first-generation mobile phones was based on analogue radio technology. It was composed of three elements - mobile telephone, cell sites and mobile switching centres (MSC). The system was designed using two different radio channels. The first was the control channel, and the second was the voice channel.
THIRD-GENERATION MOBILE SYSTEMS Table 1.1 Various cellular and mobile technologies
Technology speed Launch Benefits Drawbacks Bottom-line
GPRS 171.2 kbps 2001 Packet data Data rates Will be the
for GSM may most successful
world disappoint technology
HSCSD 115 kbps In use Dedicated Low Will not be
channels deployment, mainstream
EDGE 384 kbps 2003 Higher data Expensive, Will not
Classic rates for little be able to
both packet terminal compete with
and circuit support W-CDMA
EDGE 250 kbps 2002 Higher data AT&T Unlikely to
Compact rates for (main be successful
both packet proponent)
and circuit has changed
CDMA/ 115 kbps In use Interim Only adopted Most carriers
IS-95B packet in Japan and will prefer