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V 2.2 Copyright SystemExperts 2001,2002,2003

191

Glossary

3G (third generation) An industry term used to describe the next, still-to-come generation of wireless applications. It

represents a move from circuit-switched communications (where a device user has to dial in to a network) to broadband,

high-speed, packet-based wireless networks (which are always "on"). The first generation of wireless communications

relied on analog technology, followed by digital wireless communications. The third generation expands the digital

premise by bringing high-speed connections and increasing reliability.

802.11 A family of wireless specifications developed by a working group of The Institute of Electrical and Electronics

Engineers. These specifications are used to manage packet traffi c over a network and ensure that packets do not collide—

which could result in loss of data—while traveling from their point of origin to their destination (that is, from device to

device).

AMPS (advanced mobile phone service) A term used for analog technologies, the first generation of wireless technologies.

Analog Radio signals that are converted into a format that allows them to carry data. While cellular phones and other wireless

devices still use analog in geographic areas where there is little or no coverage by digital networks, analog will eventually

give way to faster digital networks, analysts say.

AP (Access Point) A base station in a wireless LAN. Access points are typically standalone devices that plug into an Ethernet

hub or server. Like a cellular phone system, users can roam around with their mobile devices and be handed off from one

access point to the other.

BlackBerry Two-way wireless device, made by Waterloo, Ontario-based Research in Motion, that allows users to check e-

mail and voice mail (translated into text), as well as page other users via a wireless network service. Also known as a

RIM device, it has a miniature qwerty keyboard for users to type their messages. It uses the SMS protocol. BlackBerry

users must subscribe to a wireless service that allows for data transmission.

Bluetooth A short-range wireless specification that allows for radio connections between devices within a 30-foot range of

each other.

CDMA (code division multiple access) U.S. wireless carriers, such as Sprint PCS and Verizon, use CDMA to allocate

bandwidth for users of digital wireless devices. CDMA distinguishes between multiple transmissions carried

simultaneously on a single wireless signal. It carries the transmissions on that signal, freeing network room for the

wireless carrier and providing interference-free calls for the user. Several versions of the standard are still under

development. CDMA promises to open up network capacity for wireless carriers and improve the quality of wireless

messages and users' access to the wireless airwaves. It's an alternative to GSM, which is popular in Europe and Asia.

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Glossary (cont.)

CDPD (cellular digital packet data) Telecommunications companies can use CDPD to transfer data on unused cellular

networks to users. If one section, or "cell," of the network is overtaxed, CDPD automatically allows for the reallocation of

resources.

COFDM (Coded Orthogonal Frequency Division Multiplexing) The same as OFDM except that forward error correction is

applied to the signal before transmission. This is to overcome errors in the transmission due to lost carriers from

frequency selective fading, channel noise and other propagation effects. For the discussion of terms OFDM and COFDM

are used interchangeably

Cellular Technology that sends analog or digital transmissions from transmitters that have areas of coverage called cells. As a

user of a cellular phone moves between transmitters from one cell to another, the user's call travels from transmitter to

transmitter uninterrupted.

Circuit switched Used by wireless carriers, this method lets a user connect to a network or the Internet by dialing in, such as

with a traditional phone line. It's a dial-in Internet service provider for wireless device users. Circuit-switched connections

can be slow and unreliable compared with packet-switched networks, but for now circuit-switched networks are the

primary method of Internet and network access for wireless users in the United States.

Dual-band mobile phonePhones that support both analog and digital technologies by picking up analog signals when digital

signals fade. Most mobile phones are not dual-band.

Extensible Authentication Protocol (EAP) An extension to PPP, that provides a standard support mechanism for

authentication schemes such as token cards, Kerberos, Public Key, and S/Key.

EDGE (enhanced data GSM environment) A faster version of the GSM standard. It is faster than GSM because it can carry

messages using broadband networks that employ more bandwidth than standard GSM networks.

FDMA (frequency division multiple access) An analog standard that lets multiple users access a group of radio frequency

bands and eliminates interference of message traffic.

Frequency hopping spread spectrum A method by which a carrier spreads out packets of information (voice or data) over

different frequencies. For example, a phone call is carried on several different frequencies so that when one frequency is

lost another picks up the call without breaking the connection.

GPS (Global Positioning System) A series of 24 geo-synchronous satellites that continually transmit their position. GPS is

used in personal tracking, navigation, and automatic vehicle location technologies.

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