Chapter 8 Review
Geostationary Earth Orbit (GEO)
22,300 mile orbit, 8 satellites, used for TV signals
Low Earth Orbit (LEO)
400-700 mile orbit, many satellites, used for telephone and internet
Middle Earth Orbit (MEO)
6,434 mile orbit, 10-12 satellites, used for Global Positioning Systems (GPS)
Global Positioning Systems (GPS)
A wireless system that utilizes satellites to enable users to determine their position anywhere on Earth; Supported by 24 MEO satellites
Short-Range Wireless Networks
Bluetooth, Ultra-Wideband, Near-Field communications
Wide-Area Wireless Networks
Cellular Radio (Cellular telephones), Wireless Broadband (or WiMax)
Three Major Advantages of Wireless Devices (3)
Communicate wirelessly with the Internet & other devices
WTM Radio Disadvantages
Creates electrical interference problems, Susceptible to 'snooping' unless encrypted
Mobile Commerce
Electronic commerce transactions conducted in a wireless environment, especially via the Internet
WTM Satellite Disadvantages
Expensive; Requires unobstructed line of sight; Signals experience propagation delay; Requires the use of encryption for security
Three Types of Satellites
Geostationary Earth Orbit (GEO), Middle Earth Orbit (MEO), Low Earth Orbit (LEO)
WTM Radio Advantages
High Bandwidth, Signals pass through walls, Inexpensive and easy to install
WTM Satellite Advantages
High bandwidth; Large coverage area
WTM Microwave Advantages
High bandwidth; Relatively Inexpensive
Pervasive Computing
Invisible "everywhere computing" that is embedded in the objects around us
WTM Infrared Advantages
Low to medium bandwidth, Used only for short distances
Two Major Characteristics of Mobile Computing
Mobility and Broad Reach
Internet over Satellite Advantage
Propagation delay; Disrupted by environmental conditions
Internet over Satellite Disadvantage
Provides Internet services to remote areas of Earth
Mobile Computing
Refers to a real-time connection between a mobile device and other computing environments, such as the Internet or an Intranet
WTM Infrared Disadvantages
Requires an unobstructed line of sight
WTM Microwave Disadvantages
Requires an unobstructed line of sight; Susceptible to environmental interference
Four Major Threats of Wireless Security
Rogue access points, war driving, eavesdropping, radio-frequency jamming
Characteristics of LEO
Satellites move rapidly relative to point on Earth; Large number needed for global coverage; Requires only low-power transmitters; Negligible transmission delay; Least expensive to build and launch; Shortest orbital life
Characteristics of MEO
Satellites move relative to point on Earth; Moderate number needed for global coverage; Requires medium-powered transmitters; Negligible transmission delay; Less expensive to build and launch; Moderate orbital life
Characteristics of GEO
Satellites stationary relative to point on Earth; Few satellites needed for global coverage; Transmission delay; Most expensive to build and launch; Longest orbital life
Three Major Advantages of Wireless Devices (1)
Small enough to easily carry or wear
Three Major Advantages of Wireless Devices (2)
Sufficient computing power to perform productive tasks
5 Value-Added Attributes of Mobility and Broad Reach
Ubiquity, convenience, instant connectivity, personalization, localization of products and services
Drivers of M-Commerce
Widespread availability of mobile devices, Declining prices, Bandwidth improvement
Medium-Range Wireless Networks
Wireless Fidelity (WiFi), Wireless Mesh Networks
Types of WiFi
Wireless Local Area Network (WLAN), Wi-Fi Direct, MiFi, Super Wi-Fi
One Major Disadvantage for Business Regarding Wireless Devices
Workers can capture and transmit sensitive proprietary information