Tp-Link TL-WN321G [39/41] Appendix a glossary

TL-WN321G 54Mbps Wireless USB Adapter User Guide

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Appendix A: Glossary

802.11b - The 802.11b standard specifies a wireless networking at 11 Mbps using

direct-sequence spread-spectrum (DSSS) technology and operating in the unlicensed radio

spectrum at 2.4GHz, and WEP encryption for security. 802.11b networks are also referred to as

Wi-Fi networks.

802.11g - Specification for wireless networking at 54 Mbps using direct-sequence

spread-spectrum (DSSS) technology, using OFDM modulation and operating in the unlicensed

radio spectrum at 2.4GHz, and backward compatibility with IEEE 802.11b devices, and WEP

encryption for security.

Ad-hoc Network - An ad-hoc network is a group of computers, each with a wireless adapter,

connected as an independent 802.11 wireless LAN. Ad-hoc wireless computers operate on a

peer-to-peer basis, communicating directly with each other without the use of an access point.

Ad-hoc mode is also referred to as an Independent Basic Service Set (IBSS) or as peer-to-peer

mode, and is useful at a departmental scale or SOHO operation.

DSSS (Direct-Sequence Spread Spectrum) - DSSS generates a redundant bit pattern for all data

transmitted. This bit pattern is called a chip (or chipping code). Even if one or more bits in the chip

are damaged during transmission, statistical techniques embedded in the receiver can recover

the original data without the need for retransmission. To an unintended receiver, DSSS appears

as low power wideband noise and is rejected (ignored) by most narrowband receivers. However,

to an intended receiver (i.e. another wireless LAN endpoint), the DSSS signal is recognized as the

only valid signal, and interference is inherently rejected (ignored).

FHSS (Frequency Hopping Spread Spectrum) - FHSS continuously changes (hops) the carrier

frequency of a conventional carrier several times per second according to a pseudo-random set of

channels. Because a fixed frequency is not used, and only the transmitter and receiver know the

hop patterns, interception of FHSS is extremely difficult.

Infrastructure Network - An infrastructure network is a group of computers or other devices,

each with a wireless adapter, connected as an 802.11 wireless LAN. In infrastructure mode, the

wireless devices communicate with each other and to a wired network by first going through an

access point. An infrastructure wireless network connected to a wired network is referred to as a

Basic Service Set (BSS). A set of two or more BSS in a single network is referred to as an

Extended Service Set (ESS). Infrastructure mode is useful at a corporation scale, or when it is

necessary to connect the wired and wireless networks.

Spread Spectrum - Spread Spectrum technology is a wideband radio frequency technique

developed by the military for use in reliable, secure, mission-critical communications systems. It is

designed to trade off bandwidth efficiency for reliability, integrity, and security. In other words,

more bandwidth is consumed than in the case of narrowband transmission, but the trade off

produces a signal that is, in effect, louder and thus easier to detect, provided that the receiver

knows the parameters of the spread-spectrum signal being broadcast. If a receiver is not tuned to

the right frequency, a spread-spectrum signal looks like background noise. There are two main