Glossary

1XMC (Multi-Carrier)

Also called 1XRTT, a narrowband CDMA system that offers data speeds of up to 384 kbps.

1Xtreme

Narrowband CDMA system promoted by Motorola and Nokia, offering data rates of up to 5.2 Mbps.

3G (third generation)

Generic name for mobile systems offering performance similar to an ISDN line, the first two generations being the existing analog and digital cellular networks respectively.

3XMC (Multi-Carrier)

Wideband CDMA system offering data rates of up to 4 Mbps.

802.11

IEEE committee responsible for setting wireless LAN standards.

Air Interface

The physical layer protocol used to send information over radio waves, including the multiplexing and modulation schemes.

AM (Amplitude Modulation)

Method of encoding data onto a wave by varying its transmission power.

AMPS (Advanced Mobile Phone System)

The analog mobile phone standard used in North and South America and some parts of Asia.

ANSI (American National Standards Institute)

Body that formally approves standards in the U.S.

ANSI-136

Narrowband TDMA standard, which uses the same frequency as the analog AMPS system, and hence is also known as Digital AMPS.

antenna

Electrical conductor used to transmit and/or receive radio waves.

bandwidth

The amount of radio spectrum used by or available to a service.

baud rate

The number of modulation symbols transferred per second. A modulation symbol may represent one or more bits.

bit (binary digit)

The smallest unit of information, a single 0 or 1.

Bluetooth

Initiative from more than 1,000 companies to set a standard for ubiquitous wireless networks. It aims to fit a 1 Mbps transceiver onto a single chip priced at $1.

BRAN (Broadband Radio Access Network)

European project that aims to create wireless local loop and LAN standards, including HiperLan, HiperLink and HiperAccess.

bridge

A device that passes data between separate networks without examining or processing it.

broadcast

Transmission intended for more than one recipient.

BSC (Base Station Controller)

Device that converts signals to and from the format used when they are transmitted over the air. One BSC may control several base stations.

BTS (Base Transceiver Station)

Powerful radio equipment that cellular operators need to place at the center of each cell, usually called simply a base station.

byte

A group of bits, usually eight, that represents a character and is handled as a unit.

capacity

The raw data rate of a communications link, measured in bits per second.

CDMA (Code Division Multiple Access)

A method of sharing frequency among many users by encrypting each user's signal using a different code.

cdma2000

A group of technologies that upgrade cdmaOne networks to data rates of at least 2 Mbps.

cdmaOne

A brand name of the CDMA Development Group, a vendor association, for the present CDMA standards IS-95a and IS-95b.

CDPD (Cellular Digital Packet Data)

A way to send data packets over one channel in an AMPS network.

carrier frequency

A waveform that can be modulated to carry information.

cellular

Any wireless network made from overlapping radio cells, especially the older analog mobile phone systems.

CEPT (Conference of European Post and Telecommunications Authorities)

Former intergovernmental body that designed the GSM system.

channel

A communications path between two or more points.

circuit-switched

A type of network that temporarily creates an actual physical path between parties while they are communicating.

CLEC (Competitive Local Exchange Carrier)

A company that runs telecommunications networks in competition with the local phone operator, often over the operator's own copper network.

C-Netz

An analog cellular system used in Germany and other central European countries.

Codec (Coder/decoder)

Software used to convert analog signals, such as voice, to digital data.

compression

A technique that eliminates redundant information to increase data throughput.

connectionless

A protocol or service that does not require a logical connection and does not send automatic acknowledgements when data is received.

connection-oriented

A protocolor service that sets up a logical (but not necessarily physical) connection between communicating parties.

cordless

A private wireless system that provides short-range mobility.

core network

The physical infrastructure that links together all the radio transceivers in a cellular network. Existing core networks are circuit-switched and will have to be replaced by IP backbones for data services.

CT2 (Cordless Telephony 2)

A mobile technology developed in the UK that allowed people to make calls but not receive them. Also known as Telepoint.

daisychaining

The connection of multiple devices serially, often in a ring topology.

D-AMPS (Digital AMPS)

Narrowband TDMA standard that uses the same frequencies as the analog AMPS system, also known as ANSI-136.

datagram

A unit of data that can be delivered independently of others, used in connectionless services.

DECT (Digital European Cordless Telephony)

A cordless standard designed to work alongside GSM.

de-facto standard

A system that has become widely used, although not ratified by any standards body. Examples include WAP and the Qwerty keyboard.

DSL (Digital Subscriber Line)

A family of technologies that transmit data over unused frequencies in ordinary copper phone lines.

DSP (digital signal processor)

A high-speed processor designed for digitizing analog signals and vice versa, used in all mobile phones.

DSSS (Direct Sequence Spread Spectrum)

A spread spectrum system that transmits on many frequencies simultaneously.

EDGE (Enhanced Data rates for Global Evolution)

An advanced upgrade to GPRS systems, which uses improved modulation to triple data capacity.

encryption

The process of encoding data before transmission so that an eavesdropper cannot decipher it.

ERMES (European Radio Messaging System)

A paging standard used in Europe.

Ethernet

An industry standard LAN system that operates at 10, 100, 1,000 and 10,000 Mbps.

ETSI (European Telecommunications Standards Institute)

Europe's main standards body, whose projects include GSM, UMTS, and DECT.

extranet

A network using Internet protocols, usually including the World Wide Web, to communicate with select individuals outside an organization.

FCC (Federal Communications Commission)

A government agency responsible for licensing spectrum and regulating telecommunications in the U.S.

FDD (Frequency Division Duplex)

The allocation of one frequency to the uplink and another to the downlink, allowing simultaneous transmission and reception. Also known as paired spectrum.

FDMA (Frequency Division Multiplex Access)

A method of sharing spectrum between users by dividing it into discrete channels.

FHSS (Frequency Hopping Spread Spectrum)

A spread spectrum system that rapidly switches between seemingly random frequencies.

fiber

Strands of glass used to carry optical signals.

Flex

A popular paging system developed by Motorola.

FM (Frequency Modulation)

A method of encoding data onto a wave by varying its transmission frequency.

FSK (Frequency-Shift Keying)

A type of FM that uses discrete tones to represent symbols in a data stream.

geostationary

A perfectly circular orbit exactly 35,785 km above the equator, in which a satellite will remain stationary with respect to the Earth's surface.

geosynchronous

An orbit of average height 35,785 km above the equator, not necessarily exactly circular. Geosynchronous satellites may move north or south and up or down, but not east or west.

GGSN (Gateway GPRS Support Node)

An interface between a GPRS network and an external network such as the Internet.

GMSC (Gateway Mobile Switching Center)

The interface between a mobile network and the PSTN.

GMSK (Gaussian Minimum-Shift Keying)

A phase modulation technique which employs one bit per waveform symbol, used in GSM.

GPRS (General Packet Radio Service)

An upgrade to GSM networks that offers each user up to eight 14.4 kbps channels, and employs packet-switching to use bandwidth more efficiently.

ground station

Installation of radio equipment designed to track and control satellites.

GSM (Global System for Mobile Communications)

A wideband TDMA standard originally developed in Europe but used worldwide.

Handoff

The transfer of a mobile terminal from one base station to another as it moves between cells; also called handover.

Handheld PC

Microsoft's name for small devices that run Windows CE and have a keyboard.

HDR (High Data Rate)

A narrowband CDMA system developed by Qualcomm that offers high-speed data, but not voice.

HiperAccess

A proposed future wireless local loop technology using the 5 GHz band.

HiperLan

Two incompatible wireless LAN systems that operate in the 5GHz band.

HiperLink

A proposed future wireless LAN or local loop system using 17 GHz spectrum.

HLR (Home Location Register)

A database that keeps track of all the mobile terminals that usually reside within a group of cells.

HomeRF

A wireless LAN standard designed for consumer devices operating in the 2.4 GHz ISM band.

HSCSD (High Speed Circuit Switched Data)

A software upgrade to GSM networks that gives each user up to four 14.4 kbps circuits.

HTML (Hypertext Markup Language)

A programming code used to describe Web pages and interpreted by a browser.

infrared

Light with frequencies just below the visible spectrum, used by lasers and for simple cordless networking.

IrDA (Infrared Data Association)

A consortium governing the standards supported by the infrared ports fitted to many laptops and PDAs.

IEEE (Institute of Electrical Engineers)

A professional society responsible for many networking standards, notably Ethernet and its wireless derivative 802.11.

iDEN (Integrated Digital Enhanced Network)

A digital PMR system developed by Motorola and operated in the U.S. by Nextel.

IMT-2000 (International Mobile Telecommunications)

An ITU initiative to create a global standard for third-generation wireless data networks, providing 2 Mbps when stationary and 384 kbps when mobile. Includes three modes of operation: UMTS/WCDMA, EDGE/UWC-136, and cdma2000.

IP (Internet Protocol)

The protocol governing how data packets are routed across the Internet.

IP Address

A unique number of either 32 or 128 bits that specifies a device on the Internet or other IP network.

IS-54

An older version of the ANSI-136 or D-AMPS standard, lacking its text messaging features.

IS-95a

The first CDMA standard, better known under the brand name cdmaOne. It offers high-quality voice, and data at up to 14.4 kbps.

IS-95b

A software upgrade to IS-95a, which increases the maximum data rate to 115.2 kbps.

IS-95c

Another name for 1XMC, the upgrade to IS-95b that increases maximum data rate to 384 kbps.

ISDN (Integrated Services Digital Network)

A fully digital communications network, providing channels of 64 kbps each.

ITU (International Telecommunications Union)

An agency of the United Nations that covers worldwide communications regulation and allocates radio spectrum.

Java

A programming language developed by Sun Microsystems, and usually interpreted within a Web browser.

jitter

Variation in latency, which in extreme cases can cause packets to arrive in the wrong order.

key

A code used to encrypt and/or decrypt messages.

LAN (Local Area Network)

A data network connecting nearby devices, usually within the same building or office.

latency

The time taken for a unit of information to pass through a part of a network, such as a wire or router.

leased line

A dedicated circuit that permanently connects two or more locations and is for their sole use.

LMDS (Local Multipoint Distribution Service)

High-speed, short-range wireless local loop technology.

MAN (Metropolitan Area Network)

A high speed communications network operating within a city, usually based on fiber or microwave radio.

MBS (Mobile Broadband System)

A proposed future 4G mobile system, promising multi-megabit capacity by 2010.

MCDN (Micro Cellular Digital Network)

A proprietary mobile data network developed by Metricom. It uses a mixture of licensed and unlicensed frequencies and is marketed as Ricochet.

MExE (Mobile Execution Environment)

European standard for wireless devices that include WAP and Java.

MMDS (Multipoint Multichannel Distribution System)

A television broadcasting system adapted for use as a wireless local loop technology.

MMM (Mobile Media Mode)

A branding mark that appears on WAP-compatible hardware and services.

mobile network

A wireless network which allows users to move around freely and remain connected.

Mobitex

A packet-switched mobile data network designed by Ericsson and operated in the U.S. by Bell South.

modulation

A technique for encoding a user's information into a carrier signal.

MS (Mobile Station)

A mobile terminal such as a phone, PC card, or PDA.

MSC (Mobile Switching Center)

The telephone exchange that aggregates and switches voice calls to and from a mobile network.

multicast

A message transmitted separately to several recipients.

multimedia

A combination of two or more media, usually including video or sound.

multiplexing

Division of a channel into two or more subchannels so that it can be shared by more than one user or application.

multipoint

A base station that can connect to several subscribers at once, either by blanketing an entire area or by targeting them with individual antennas.

node

Anything connected to a network.

NTSC (National Television Systems Committee)

A TV broadcasting system using 525 picture lines and a refresh rate of 60Hz, used in North America and Japan.

OFDM (Orthogonal Frequency Division Multiplex)

A system that divides a high-capacity data stream into multiple streams of lower capacity and sends each separately.

packet

A datagram that is routed between an origin and a destination, both of which are encoded into the packet itself rather than into the route.

packet-switched

A type of network in which small units of data are routed through a network based on the address contained within each packet. Packets may take different routes to the same destination, where they will be reassembled.

paging

A radio system for transmitting short text messages, usually only one-way.

PAL (Phase Alternate Line)

TV broadcasting system developed in Germany and the UK that uses 650 picture lines and a 50 Hz refresh rate.

PAN (Personal Area Network)

A very short-range wireless data network that connects all the gadgets carried by a person, interacting as necessary with those of other people.

PCN (Personal Communications Network)

Another name for GSM, particularly systems based on frequencies in the 1800 MHz band.

PCS (Personal Communications Service)

A generic name for any digital mobile voice or data service, especially those which use the 1900 MHz band in the U.S.

PCU (Packet Control Unit)

A device that must be added to older GSM base stations if they are to carry GPRS traffic.

PDA (Personal Digital Assistant)

A pocket-sized computer typically used to store names and addresses, but increasingly incorporating wireless communications applications.

PDC (Personal Digital Cellular)

A TDMA digital standard used only in Japan, based on D-AMPS.

phase modulation

A method of encoding data onto a carrier by varying the phase of its waves.

PHS (Personal Handyphone System)

A Japanese telepoint standard that allows users to make calls while roaming, but not to receive them.

PMR (Private Mobile Radio)

A cellular system that allows direct communication between two terminals when out of range of a base station. Examples include iDEN and TETRA.

point-to-point

A direct link between two nodes.

protocol

A set of rules governing the format and transmission of data.

PSK (Phase-Shift Keying)

A type of phase modulation that uses preset phase changes to represent digital symbols, rather than relative changes of phase.

PSTN (Public Switched Telephone Network)

The regular non-mobile telephone system.

QAM (Quadrature Amplitude Modulation)

A combination of amplitude and phase modulation, used in many mobile systems.

RBOC (Regional Bell Operating Company)

One of the local telcos spun off from AT&T in 1984, known as Baby Bells.

roaming

The movement of a mobile terminal outside its home cell, especially to another network in another country.

routing

Decisions regarding the communications path taken by a message or telephone call.

satellite

An orbital communications relay station, usually placed in a geostationary position.

SGSN (Serving GPRS Support Node)

A computer that routes data between a GPRS backbone and a mobile terminal, via a base station.

SIM (Subscriber Identity Module)

A smart card that fits inside digital phones or wireless data devices and contains all information particular to a mobile subscriber, including phone number, network operator, and the user's phone directory.

SMS (Short Message Service)

A feature available with some mobile phones that allow users to send and receive short alphanumeric messages.

SSL (Secure Sockets Layer)

An encrypting protocol designed for secure transactions over the Internet.

TACS (Total Access Communication System)

An analog cellular system used in Europe and Africa, but being phased out in favor of GSM.

TCP/IP (Transport Control Protocol)

A connection-oriented protocol used on the fixed Internet to verify that sent data has been received.

TDD (Time Division Duplexing)

The sharing of a frequency band between the uplink and downlink, so that a user cannot transmit and receive at once.

TDMA (Time Division Multiple Access)

A method of sharing one frequency between several users by dividing it into discrete time slots; often used to refer to the D-AMPS system.

Telepoint

A cordless system that allows a phone to make calls by connecting to low-power base stations in public places, such as railway stations, airports, and shopping malls.

TETRA (Terrestrial Trunked Radio)

A European standard for digital PMR, offering data rates up to 28.8 kbps.

UMTS (Universal Mobile Telecom System)

A European standard for third-generation wireless networks, using WCDMA and new spectrum in the 2 GHz band.

U-NII (Unlicensed National Information Infrastructure)

Spectrum set aside by the FCC for unlicensed data links.

USSD (Unstructured Supplementary Services Data)

A protocol for two-way alphanumeric messaging over a digital mobile network, allowing users to interact in real-time with a remote server such as a WAP gateway.

UWC-136 (Universal Wireless Communications)

Another name for EDGE, the TDMA-based 3G network.

WAP (Wireless Application Protocol)

Stack of protocols designed for sending simplified Web pages to wireless devices. It replaces Web protocols with its own, and requires that pages be written in WML instead of HTML.

Web Clipping

A proprietary system developed by 3COM that delivers Web content to Palm devices.

WCDMA (Wideband CDMA)

A CDMA system that uses 5 GHz channels and can hand calls over to GSM.

WML (Wireless Markup Language)

A programming language used to specify Web pages optimized for small wireless devices such as mobile phones.