Difference between revisions of "WiFi abbreviations"

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| OFDM || Orthogonal Frequency Division Multiplexing || Popular Spread Spectrum technology transmitting between 52 subcarriers
 
| OFDM || Orthogonal Frequency Division Multiplexing || Popular Spread Spectrum technology transmitting between 52 subcarriers
 
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| FEC || Forward Error Correction || Allows the receiving system to detect and correct bit errors.
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| WWAN || Wireless Wide Area Network || Wireless Network spanning wide areas for example GSM or LTE
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| WMAN || Wireless Metropolitan Area Network || Wireless Network spanning cities for example WiMax
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| WPAN || Wireless Personal Area Network || Wireless Network spanning small personal areas for example Bluetooth or infrared
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| WLAN || Wireless Local Area Network || Wireless Network spanning buildings/campusses for example WiFi/802.11
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| IS || Integration Service || The process of transforming the MSDU (802.11) frame to other frame standards. Normally ethernet
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| DS || Distribution System ||
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| CAM || Content Addressable Memory || MAC address table in a switch used to process packets based on destination MAC address
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| DSS || Distributed System Services ||
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| MSDU || MAC Service Data Unit || Upper layer information in data unit in the body of a 802.11 data frame
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| WDS || Wireless Distribution System ||
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| SSID || Service Set Identifier ||
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| BSS || Basic Service Set ||
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| BSSID || Basic Service Set Identifier ||
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| BSA || Basic Service Area ||
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| ESS || Extended Service Set ||
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| IBSS || Independent Basic Service Set ||
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| MBSS || Mesh Basic Service Set ||
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| AP || Access point || Gives wireless clients access to the network services.
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| DCF || Distributed Coordination Function || The 802.11 fundamental media access method.
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| PCF || Point Coordination Function || Access Point coordinated media access.
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| HCF || Hybrid Coordination Function ||
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| CSMA/CA || Carrier Sense Multiple Access with Collision Avoidance || Wireless media access method principle.
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| IFS || Interframe Space || period of time that exists between transmissions of wireless frames.
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| RIFS || Reduced Interframe Space || Highest priority IFS
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| SIFS || Short Interframe Space || Second highest priority IFS
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| PIFS || PCF Interframe Space || Middle priority IFS
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| DIFS || DCF Interframe Space || Lowest priority IFS
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| AIFS || Arbitration Interframe Space || IFS used by QoS stations
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| EIFS || Extended Interframe Space || IFS used with retransmissions.
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| ACK frame || Acknowledge Frame|| Acknowledge the reception of a frame by transmitting an acknowledge frame.
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| RTS || Request To Send || A signal requesting the wireless media.
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| CTS ||Clear To Send || A signal after RTS acknowledging permission to transmit. 
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| NAV || Network Allocation Vector || A timer initiated by the Duration field in 802.11 frames by stations. It is illegal to transmit in this period. Also known as Virtual Carrier sense. Operates on OSI layer 2.
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| CCA  || Clear Channel Assesment || Listening to physical medium if a transmission is in progress. Also known as Physical Carrier Sense. Operates on OSI layer 1.
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| PCF || Point Coordination Function || The AP uses polling to ask the clients if they want media access. DCF and PCF are two different media access methods, which can work together.
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| PC || Polling Coordinator || When the AP actively coordinates PCF it's called a PC
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| CFP || Contention Free Period || When the AP uses PCF it alternates between DCF and PCF. When works in PCF mode during CFP.
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| CP || Contention Period || When an AP works as PC in PCF mode the CP is the period it actively poll the clients
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| EDCA || Enhanced Distributed Channel Access || Extension of DCF using up to eight user priority (UP) levels ginving QoS at the MAC level.
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| EDCAF || EDCA Function || Frames with highest priority access have the lowest back-off values.
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| UP || User Priority || Used in EDCA to give up to eight UP levels making QoS possible. Identical to 802.3D (CoS) QoS priority
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| AC_BK || Access Category Background || Low priority highest back-off value
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| AC_BE || Access Category Best Effort || Low priority high back-off value
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| AC_VI || Access Category Video || Low priority low back-off value
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| AC_VO || Access Category Voice || Low priority lowest back-off value
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| HCCA || HCF Controlled Channel Access ||
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| CAP || Controlled Acess Phase || Used in HCCA mode to allow contention free transfer of QoS data.
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| HC || Hybrid Coordinator || QoS aware centralized coordinator build into an AP
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| TXOP || Transmit Opportunity || When a HCF-compliant contends for the medium it receives an alooted amount of time to send frames called TXOP
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[[Category:WiFi]]
 
[[Category:WiFi]]

Latest revision as of 13:26, 24 February 2014

Abbreviations

WiFi or 802.11 abbreviations
Abb. meaning Notes
ASK Amplitude Shift Keying Keying 0's and 1's by altering the radio carriers amplitude
FSK Frequency Shift Keying Keying 0's and 1's by altering the radio carriers frequency
PSK Phase Shift Keying Keying 0's and 1's by altering the radio carriers phase
MPSK Multiple Phase Shift Keying Keying more than one bit at a time by using four or more phases
IR Intended Radiator The active RF transmitter
RF Radio Frequency Rate of oscillation in the range of around 3 kHz to 300 GHz corresponding to radio waves
FSPL Free Space Path Loss Loss of amplitude of the signal in free space over distance
ISI Intersymbol Interference Signal misinterpreted by receiver due to multipath signals out of phase
EIRP Equivalent isotropically radiated power The highest RF signal strength transmitted from a particular antenna. Often expressed in dBm
RSSI Received Signal Strength Indicator power level received by the receiver radio in dbm
mW Milli Watt 0,001 Watt
dB Decibel Logarithmic unit used to express the ratio between two values. dB = 10 x log10 Ratio1 / Ratio2
dBm Decibel milliwatt Decibel relative to 1 mW of power.
dBi Decibel isotropic Antenna gain compared to a theoretical isotropic antenna
dBd Decibel dipole Antenna gain compared to a theoretical isotropic antenna. Add 2,14 dB to get dBi
SNR Signal to Noise Ratio Distance between received signal and noise floor. Expressed in dB
DRS Dynamic Rate Switching Switching to a higher/lower data rate as the received signal increases/decreases
ISM Industrial Scientific and Medical 902 - 928 MHz, 2,4 - 2,5 GHz and 5,725 - 5,875 GHz bands
UNII Unlicensed National Information Infrastructure Three 5 Ghz bands each with 100 MHz bandwidth
UNII-1 UNII-1 (lower band) 5,150 - 5,250 GHz band ( 4 channels )
UNII-2 UNII-2 (Middle band) 5,250 - 5,350 GHz band ( 4 channels )
UNII-2E UNII-2 Extended 5,470 - 5,725 GHz band 255 MHz bandwidth ( 11 channels )
UNII-3 UNII-3 (Upper band) 5,725 - 5,825 GHz band ( 4 channels )
FHSS Frequency Hopping Spread Spectrum Transmitting data in small chunks hopping from frequency to frequency
DSSS Direct Sequence Spread Spectrum Transmitting data is spread across the range of frequencies of the channel. 11 bit PN
GFSK Gaussian Frequency Shift Keying FSK modulator using a Gaussian filter to reduce spectral width.
PN Pseudorandom number Used with DSSS to encode 1 bit to 11 bits to reduce transmission errors.
CCK Complementary Code Keying Used with HR-DSSS to encode 4 bits data to 8 bits using a 8 bit PN
HR-DSSS High Rate DSSS Uses CCK encoding to get higher data rate than DSSS
DQPSK Differential Quadrature Phase Shift Keying Modulation using four phase shifts each representing two bits
OFDM Orthogonal Frequency Division Multiplexing Popular Spread Spectrum technology transmitting between 52 subcarriers
FEC Forward Error Correction Allows the receiving system to detect and correct bit errors.
WWAN Wireless Wide Area Network Wireless Network spanning wide areas for example GSM or LTE
WMAN Wireless Metropolitan Area Network Wireless Network spanning cities for example WiMax
WPAN Wireless Personal Area Network Wireless Network spanning small personal areas for example Bluetooth or infrared
WLAN Wireless Local Area Network Wireless Network spanning buildings/campusses for example WiFi/802.11
IS Integration Service The process of transforming the MSDU (802.11) frame to other frame standards. Normally ethernet
DS Distribution System
CAM Content Addressable Memory MAC address table in a switch used to process packets based on destination MAC address
DSS Distributed System Services
MSDU MAC Service Data Unit Upper layer information in data unit in the body of a 802.11 data frame
WDS Wireless Distribution System
SSID Service Set Identifier
BSS Basic Service Set
BSSID Basic Service Set Identifier
BSA Basic Service Area
ESS Extended Service Set
IBSS Independent Basic Service Set
MBSS Mesh Basic Service Set
AP Access point Gives wireless clients access to the network services.
DCF Distributed Coordination Function The 802.11 fundamental media access method.
PCF Point Coordination Function Access Point coordinated media access.
HCF Hybrid Coordination Function
CSMA/CA Carrier Sense Multiple Access with Collision Avoidance Wireless media access method principle.
IFS Interframe Space period of time that exists between transmissions of wireless frames.
RIFS Reduced Interframe Space Highest priority IFS
SIFS Short Interframe Space Second highest priority IFS
PIFS PCF Interframe Space Middle priority IFS
DIFS DCF Interframe Space Lowest priority IFS
AIFS Arbitration Interframe Space IFS used by QoS stations
EIFS Extended Interframe Space IFS used with retransmissions.
ACK frame Acknowledge Frame Acknowledge the reception of a frame by transmitting an acknowledge frame.
RTS Request To Send A signal requesting the wireless media.
CTS Clear To Send A signal after RTS acknowledging permission to transmit.
NAV Network Allocation Vector A timer initiated by the Duration field in 802.11 frames by stations. It is illegal to transmit in this period. Also known as Virtual Carrier sense. Operates on OSI layer 2.
CCA Clear Channel Assesment Listening to physical medium if a transmission is in progress. Also known as Physical Carrier Sense. Operates on OSI layer 1.
PCF Point Coordination Function The AP uses polling to ask the clients if they want media access. DCF and PCF are two different media access methods, which can work together.
PC Polling Coordinator When the AP actively coordinates PCF it's called a PC
CFP Contention Free Period When the AP uses PCF it alternates between DCF and PCF. When works in PCF mode during CFP.
CP Contention Period When an AP works as PC in PCF mode the CP is the period it actively poll the clients
EDCA Enhanced Distributed Channel Access Extension of DCF using up to eight user priority (UP) levels ginving QoS at the MAC level.
EDCAF EDCA Function Frames with highest priority access have the lowest back-off values.
UP User Priority Used in EDCA to give up to eight UP levels making QoS possible. Identical to 802.3D (CoS) QoS priority
AC_BK Access Category Background Low priority highest back-off value
AC_BE Access Category Best Effort Low priority high back-off value
AC_VI Access Category Video Low priority low back-off value
AC_VO Access Category Voice Low priority lowest back-off value
HCCA HCF Controlled Channel Access
CAP Controlled Acess Phase Used in HCCA mode to allow contention free transfer of QoS data.
HC Hybrid Coordinator QoS aware centralized coordinator build into an AP
TXOP Transmit Opportunity When a HCF-compliant contends for the medium it receives an alooted amount of time to send frames called TXOP
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