Chapter 8 Flashcards
def. wireless
Telecommunications in which electromagnetic waves carry the signal between communicating devices
What are three reasons individuals are finding wireless devices convenient and productive to use?
- people can make productive use of time that was formerly wasted (ex. public transport)
- people can take devices with them, work locations are more flexible
- enables people to schedule their working time around personal and professional obligations
What are the 3 major advantages of wireless devices to users?
- They are small enough to easily carry or wear.
- They have sufficient computing power to perform productive tasks.
- They can communicate wirelessly with the Internet and other devices
def. dematerialization
- what exhibits this?
occurs when the functions of many physical devices are included in one other physical device
-smart phones exhibit this
What is a downside of smart phones?
people can use them to copy and pass on confidential information
What are the major types of wireless media?
microwave, satellite, radio
def. microwave transmission systems
A wireless system that uses microwaves for high-volume, long-distance, point-to-point communication
what are the advantages of microwave transmission systems?
- High bandwidth
- Relatively inexpensive
def. line of sight
means that the transmitter nad receiver are in view of each other
What are some disadvantage of microwave transmissions?
- Must have unobstructed line of sight
- Susceptible to environmental interference
def. satellite transmission systems
A wireless transmission system that uses satellites for broadcast communications
What are some advantages of satellite transmission systems?
- High bandwidth
- Large coverage area
What are some disadvantages of satellite transmission systems?
- Expensive
- Must have unobstructed line of sight
- Signals experience propagation delay
- Must use encryption for security
What are the three basic types of telecommunications satellites?
- geostationary-earth-orbit (GEO),
- medium-earth-orbit (MEO),
- low-earth-orbit (LEO)
What overcomes the microwave data relay stations when speaking about satellites?
the enormous footprint—the area of Earth’s surface reached by a satellite’s transmission—overcomes the limitations of microwave data relay station
What is the most basic rule governing satellite footprint size?
The higher a satellite orbits, the larger its footprint
def. propagation delay
Any delay in communications from signal transmission time through a physical medium
Why is tracking LEO satellites more difficult than tracking MEO satellites?
they move much more quickly relative to a point on earth
What tracks satellites?
receivers
LEO satellites can pick up signals from ______ transmitters, unlike GEO and MEO satellites
weak
What are some advantages of LEO satellites?
- can pick up signals from weak transmitters. This feature makes it possible for satellite telephones to operate via LEO satellites, because they can operate with less power using smaller batteries.
- they consume less power and cost less to launch.
What is a disadvantage of LEO satellites?
footprints are small, meaning that more are needed to cover the planet
def. global positioning system (GPS)
A wireless system that uses satellites to enable users to determine their position anywhere on Earth
-supported by 24 MEO satellites
Internet over Satellite (IoS) uses what kind of satellies?
GEO
What are disadvantages if GEO satellites in terms of IoS
- involve a propagation delay
- can be disrupted by environmental influences
def. radio transmission
The use of radio-wave frequencies to send data directly between transmitters and receivers
Advantages of radio transmission?
- High bandwidth
- Signals pass through walls
- Inexpensive and easy to install
Disadvantages of radio transmission?
- Creates electrical interference problems
- Susceptible to snooping unless encrypted
- when you travel too far away from the source, the signal breaks up and fades to static
def. satellite radio (or digital radio)
A wireless system that offers uninterrupted, near CD-quality music that is beamed to your radio from satellites
ex. Sirium XM
What is the range of short-range wireless networks (in general)
30 metres or less
What are three basic short-range networks?
bluetooth, ultra-wideband, near-field communication
def. bluetooth
Chip technology that enables short-range connection (data and voice) between wireless devices
def. personal area network
A computer network used for communication among computer devices close to one person
def. ultra-wideband (UWB)
A high-bandwidth wireless technology with transmission speeds in excess of 100 Mbps that can be used for applications such as streaming multimedia from, say, a personal computer to a television
def. near-field communications (NFC)
The smallest of the short-range wireless networks that is designed to be embedded in mobile devices such as cell phones and credit cards
def. wireless local area networks (WLANs)
A computer network in a limited geographical area that uses wireless transmission for communication
What is the most common type of medium-range wireless network?
Wireless Fidelity (Wi-Fi)
def. Wireless Fidelity (or Wi-Fi)
A set of standards for wireless local area networks based on the IEEE 802.11 standard
def. wireless access point
An antenna connecting a mobile device to a wired local area network
def. hotspot
A small geographical perimeter within which a wireless access point provides service to a number of users
What are the major benefits of Wi-Fi?
- low cost
- ability to provife simple Internet access
What is the greatest facilitator of wireless internet?
-Wi-FI