Wireless Technologies

Wireless devices: small enough to easily carry or wear, have sufficient computing power to perform productive tasks and can communicate wirelessly with the Internet and other devices.

The wireless application protocol (WAP) is the standard that enables wireless devices to access Web-based information and services.

WAP-compliant devices contain microbrowsers, which are Internet browsers with a small file size that can work within the confines of small screen sizes on wireless devices and the relatively low bandwidths of wireless networks.

Microwave transmission systems are widely used for high-volume, long-distance, point-to-point communication. Point-to-point  has two characteristics: first, the transmitter and receiver must be in view of each other (called line-of-sight); and second, the transmission itself must be tightly directed from transmitter to receiver.

Satellite transmission systems make use of communication satellites; three types of satellites, each in a different orbit:

·         Geostationary (GEO): orbits 22,300 miles directly above the equator and maintains a relatively fixed position in relation to a dish on earth;     excellent for TV signals.

·         Medium-earth-orbit (MEO): are located 6,000 miles above the earth’s surface and move; used for the GPS system.

·         Low-earth-orbit (LEO): are 400 to 700 miles above the surface, so they move much faster with respect to a point on the earth’s surface; require many to cover the earth.

Global Positioning System: a wireless system that uses MEO satellites to enable users to determine their position anywhere on the earth.

Internet over satellite: allows users to access the Internet via GEO satellites from a dish mounted on the side of their homes.

Wireless Computer Networks and Internet Access

Short-range wireless networks generally have a range of 100 feet or less.

Medium-range wireless networks are the familiar wireless local area networks (WLANs). The most common type of medium-range wireless network is Wireless Fidelity (Wi-Fi).

Wide-area wireless networks connect users to each other and to the Internet over geographically dispersed distances.

Mobile Computing and Mobile Commerce

The characteristics, mobility and broad reach, create five value-added attributes that break the barriers of geography and time:

n  Ubiquity: mobile device can provide information and communications regardless of user’s location.

n  Convenience, Instant connectivity: Internet-enabled mobile device makes it easy and fast to access the Web, intranets, and other mobile devices without booting up a PC or placing a call.

n  Personalization: information can be customized and sent to individual consumers (e.g., as a short message service).

n  Localization of products and services: knowing a user’s location helps companies advertise their products and services.

Pervasive Computing

Pervasive Computing (Ubiquitous computing) is invisible “everywhere computing” that is embedded in the objects around us – the floors, the lights, our cars, washing machine, microwave oven, cell phones, clothes, and so on. (e.g., smart home, smart appliances)

Radio frequency identification (RFID) technology allows manufacturers to attach tags with antennas and computer chips on goods and then track their movement through radio signals.

Wireless sensor networks (WSNs) are networks of interconnected, battery-powered, wireless sensors that are placed into the physical environment.

Wireless Security

Four major threats:

·         Rogue access point: is an unauthorized access point to a wireless network.

·         War driving: is the act of locating WLANs while driving around a city or elsewhere.

·         Eavesdropping: refers to efforts by unauthorized users to try to access data traveling over wireless networks.

·         RF (Radio frequency) jamming: is when a person or a device intentionally or unintentionally interferes with your wireless network transmissions.