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Definition
| Collection of frequencies available for communication, considered a natural resource available for public use. |
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| Grants organizations in different locations exclusive rights to use each frequency. It also determines what frequency ranges can be used for what purposes. |
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| Governing body that sets standards for international wireless services, including frequency allocation, signaling, and protocols used by wireless devices; wireless transmission and reception equipment, satellites. |
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Similarities between wires and wireless
Page 346 |
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Definition
Use the same layer 3 and higher protocols.
Air provides no fixed path for signals to follow. |
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| Antennas for wireless transmission |
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Definition
| Each type of wireless service requires an antenna specifically designed for that service |
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Single direction
used when the source needs to communicate with one destination.
Point-to-point link. |
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Definition
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REFLECTION, A wireless signal will bounce off objects whose dimension are large compared with the signals average wavelength.
Wavelengths between 1 and 10 meters
signals reflect more readily off conductive materials like metal rather than insulators, like concrete. |
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Advantage: signals bounce off walls and other obstacles they have a better chance of reaching their destination.
Disadvantage:
Signals travel different distances between their transmitter and receiver, multiple instances of the same signal can arrive at a receiver at different times, causing misinterpreted data, and data errors. |
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| Error Correction algorithm |
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Definition
| Detects the errors and the sender will have to retransmit the signal. The more errors that occur the slower the throughput. |
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Definition
Multipath signaling is a significant cause of fading.
Excessive fading can cause dropped calls or slow data transmission. |
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Definition
Wireless signals experience this.
Wireless signals are amplified (analog) or repeated (digital) to strengthen the signal so it can be clearly received. |
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Definition
This is the most severe problem with wireless technologies.
Because the atmosphere is saturated with electromagnetic waves.
Center of a metropolitan area is more apt to suffer. |
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| Obstacles that affect signal travel |
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Definition
Pass through them
Be absorbed into them
Be subject to three phenomena
Reflection: bounce back to source
Diffraction: splits into secondary waves
Scattering: diffusion in multiple different directions |
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Frequency range: 2.4–2.4835 GHz
11 unlicensed communications channels
Susceptible to interference
Unlicensed: no FCC registration required |
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Frequency bands
5.1 GHz, 5.3 GHz, 5.4 GHz, 5.8 GHz
24 unlicensed bands, each 20 MHz wide
Used by weather, military radar communications |
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| Contrast between narrow band and broadband |
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Definition
NarrowBand:
A transmitter concentrates the signal energy at a single frequency or in a very small range of frequencies.
Broadband:
Uses a relatively wide band of the wireless spectrum. Offer high throughputs. |
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Definition
Use of multiple frequencies to transmit a signal.
Signal never stays continuously within one frequency range during its transmission.
Less power per frequency than narrowhead signaling.
Less likely to interfere with narrowhead signals.
First used in WWII.
If not decoded it sounds like untelligible noise. |
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Definition
Devices in the U.S split 2.4 - 2.4835 band into 79 distinct frequencies.
(Implementation of Spread Spectrum) |
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Definition
Nodes positioned need to exchange data, can be arranged in a ad hoc fashion
In an ad hoc WLAN wireless nodes or stations, transmit directly to each other via wireless NIC's without intervening connectivity device. |
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Definition
| Wireless technology can be used to connect tow different parts of a LAN or two separate LAN's. Such connections typically use a fixed link with directional antennas between two access points. |
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| Results of more energy to signal propagation |
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Definition
Because point-to-point links only have to transmit in one direction, as a result their maximum transmission distance is greater.
Two WLAN's access points could be as far as 1000ft apart. |
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| Maximum number of stations |
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Definition
| 10 - 100 depending on the wireless technology used. |
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Definition
Wireless Access method
Equipment Manufacturer
Office Environment |
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Term
| Optimal transmission Speeds |
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Definition
| WLAN stations must remain within 300 ft. of an access point to maintain. |
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| Each wireless technology is defined by a standard that describes unique functions at both the _____and_____ |
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Definition
Physical
Data link layers of the OSI Model. |
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| IEEE released its first wireless network standard in_____ |
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Definition
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Definition
802.11b
802.11a
802.11g
802.11n |
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| Although some of their Physical layer services vary all four use_____ |
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Definition
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Definition
| Can either transmit or receive, but cannot do both simultaneously. |
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Definition
| Responsible for appending physical address to a data frame and for governing multiple nodes access to a single medium. |
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| 802.11 MAC services append 48 bit (or 6byte) physical addresses to a frame to identify its____and ____ |
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Definition
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Definition
verify each transmission means that 802.11 networks require overhead than 802.3.
Wireless network with a theoretical maximum throughput of 10MBPS will transmit less data per second than a wired Ethernet network with the same theoretical maximum throughput. |
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rated for 54Mbps
Achieve 20 - 25 Mbps |
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| Efficiency of the 802.11 network |
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| Function of the MAC sublayer described in the 802.11 standard. |
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| Stations transmit special frame...Probe |
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Definition
| Special signal....Beacon Frame |
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| Client Software for access points |
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Definition
Will prioritize the access point with the strongest signal and the lowest error rate.
Does not prioritize to the closest. |
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Definition
| A user brings their own access point to turn his workstation into an access point. |
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Definition
| Connecting to a different access point. |
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| Overhead required to manage access to the 802.11 wireless networks |
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Definition
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Definition
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Definition
| Association adn reassociation such as the probe and beacon frames. |
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Medium Access
Data delivery
Such as the ACK and RTS/CTS |
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Definition
| Carry data sent between stations. |
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| Data Frame contain _____address fields |
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Definition
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| Data frame address fields |
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Definition
Source Address
Transmitter Address
Receiver Address
Destination Address |
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| Transmitter and Receiver addresses refer to the ______ |
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Definition
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Definition
| How large a packet is fragmented, subdivided into smaller packets for more reliable delivery |
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| In 802.11 networks error checking and packet fragmentation is handled at the____ |
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Definition
| MAC sublayer of the Data Link layer |
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| Frame Control field in an 802.11 data frame holds information about the____ |
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Definition
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1999
2.4 - 2.4835 GHz
22MHz Channels
11Mbps actual is 5mbps
Least expensive
100 meters or 330 feet |
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Definition
Released after 802.11b
5GHz Bands
54Mbps actual...11-18Mbps
More expensive
Less likely to suffer interference
20 meters or 66 feet |
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Definition
11 - 54 Mbps..actual 20 to 25 Mbps
Can add 11b access point without interruption of service.
100 meters or 330 feet |
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Definition
Mid 2007
600Mbps
Use either 2.4Ghz or 5GHz frequency range
Manages frames, channels, and encoding.
400 meters or 1310 feet |
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Term
WiMax
World Wide Interoperability for Microwave Access |
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Definition
2011
Intel and Nokia banded together to promote and develop 802.16 products and services.
802.16
Alternative to DSL and T carriers with less cost. |
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Definition
2005
First version for mobile clients |
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