Chapter 12: Wireless Networking Flashcards
how is data passed in wireless communication systems
they modulate data onto electromagnetic signals like radio and light waves
higher frequency carries … data over a … distance with … susceptibility to interference
carries more data but over a shorter distance and with more susceptibility to interference
Wireless communication systems use … as a medium access control protocol
CSMA/CA
CSMA/CA
carrier sense multiple access with collision avoidance
MAC
medium access control protocol
radio frequency band
a subset of the radio spectrum designated for a specific use
Wi-Fi systems operate in the … GHz bands
2.4-GHz and 5-GHz bands
Wireless communications systems use one of two modulation techniques
spread spectrum or orthogonal frequency division multiplexing
OFDM
orthogonal frequency division multiplexing
Spread spectrum modulation techniques include …
frequency hopping spread spectrum and direct sequence spread spectrum
FHSS
frequency hopping spread spectrum
DSSS
direct sequence spread spectrum
DSSS
spreads the data being transmitted over a wider spectrum than normally needed to overcome interference; relies on a chip sequence to let receiving stations know how to reconstruct the transmitted data
FHSS uses ….
uses a single subchannel at a time, but rapidly changes channels in a particular hope sequence
WLANs
Wireless local area networks
two forms of WLANs
infrastructure and ad hoc
Environments segmented into different WLANs by using …
using different SSIDs
802.11a
provides up to 54 Mbps and operates in the 5-GHz band
802.11b
provides a transfer rate of up to 11 Mbps and works in the 2.4 GHz frequency range
802.11g
operates in the 2.4-GHz band and supports data rates of up to 54 Mbps
802.11n
aka Wi-Fi 4; supports throughputs of up to 100 Mbps and works in the 5-GHz band
IEEE 802.11ac
Wi-Fi 5; an extension of 802.11n which increases throughput to 1.3 Gbps and is backward compatible with a, b, g, and n
802.11ax standard
aims to address efficiency rather than faster speeds
Li-Fi
wireless networking tech which uses light rather than radio waves to transmit and receive data
802.16
MAN wireless standard; allows wireless traffic to cover large geographical areas where stations can be as far as 70 km apart, using 2.4-GHz and 5-GHz bands
MAN
metropolitan area network
802.15.4 standard
defines the physical layer and Media Access Control sublayer of wireless personal area networks