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Wireless 5

Chapter 5

TermDefinition
16-level quadrature amplitude modulation A modulation technique that sends 16 different signals simultaneously.
2x mode A proprietary transmission scheme that doubles the effective rate if an 802.11a network
64-level quadrature amplitude modulation A modulation technique that can transmit 1.125 Mbps over each of 48 subchannels
bandwidth The difference between the upper and lower frequencies
barker code The bit pattern used in direct sequence spread spectrum modulation
Channel A numeric value assigned to a frequency range
Chipping Code THe bit pattern used in direct sequence spread spectrum
Colocation Sharing a frequency band between similar devices
communication resilience Term used to describe transmissions that are less prone to interference
Convolutional Coding rate A type of error-correcting code
Differential binary phase shift keying a two level phase shift key used in 802.11b networks
Differential quadrature phase shift keying A four level phase change used in 802.11b networks
Direct sequence spread spectrum A wireless modulation technique that uses an expanded redundant code to transmit each data bit.
Dwell Time The amount of time that a transmission remains in a specific frequency in FHSS
Dynamic Frequency Selection A technology in which IEEE 802.11n WLANS using 40-mhz channels can automatically move to another channel or switch to 20=mhz operation to minimize interference.
Extended rate PHYs (ERP) A manadory mode for the faster 54 mbps IEEE 802.11g
Forward Error Correction (FEC) An IEEE 802.11a error correction technique that transmits a secondary copy along with the primary information.
Frequency hopping spread spectrum (FHSS) A modulation technique that uses a range of frequencies that change during the transmission
Full-Channel FHSS An FHSS technology in which the devices use a minimum 75 hop channels
Guard Interval (GI) A delay built-in into the receiver to allow to late-arriving symbols
High-Rate DSSS Transmission rates above 2 mbps in IEEE 802.11b
hopping code The sequence of changing frequencies in FHSS
hop time The time it takes to change frequency in FHSS
intersymbol interference Signal interference as a result of multipath transmission
microsecond on millionth of a second
milliseconds One thousandth of a second
Modulation and coding scheme (MCS) A system that assigns a numeric value to each of the 77 possible transmission combinations IEEE 802.11n
Multiplexing The process of sending multiple signals simulanwously
Narrowband transmission Radio signals that are sent on only one radio frequency or a very narrow portion of the frequencies
OSI reference model A seven-layer model that conceptually illustrates the steps of networking
Orthogonal Frequency Division Multiplexing A modulation technique that splits a signal high speed digital signal into several slower signals running in a parallel.
PBCC-22 (Packet Binary Convolutional Coding) An optional 802.11g technique for transmitting at 22 mbps
Phased Coexistence Operation An optional IEEE 802.11n technology that alternates between using 20-mhz and 40-mhz channels
Physical Layer Convergence Procedure Procedure (PLCP) A physical layer sublayer that reformats the data received from MSC layer (when transmitting) into a frame that the PMD sublayer can transmit listens to the medium to determine when the data can be sent
Physical Medium Dependant A physical layer sublayer that defines the standards for both the characteristics of the wireless medium and the method for transmitting and receiving data through that medium
primary channel The first channel of two bonded IEEE 802.11n channels
Quadrature phase shift keying An IEEE 802.11a modulation technique that increases the amount of data encoded to 250 kbps per channel
Reduced-channel FHSS A FHSS technology in which the devices use fewer than 75 hop channels
Secondary Channel The second channel of teo bonded IEEE 802.11n channels
Spectral Efficiency The efficiency of the radio measured in the number of bits per second
Spread-spectrum transmission A technique that takes a narrow, weaker signal and spreads it over a braoder portion of the radio frequency band
Symbols Radio frequency signals
Transmit power control An IEEE 802.11a technology to reduce interference
Turbo mode A proprietary transmission scheme used to double the effective rate of an 802.11a network
Variable Guard Interval An IEEE 802.11n technology that uses a reduced guard interval of 4000 nanoseconds
complementary code keying a coding technique used in 802.11b networks that consists of a set of 64 8-bit code words
Created by: 1076635061