Glossary & Acronyms

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1G	First Generation Wireless: Analog Cellphones
1xRTT	Single Carrier (1x) Radio Transmission Technology: This technology supports peak data speeds up to 144 kbps, and up to a doubling of voice capacity.
2G	Second generation wireless systems: digital cellphones
2.5G	2G plus faster data services, also known as GPRS
3G	Third generation wireless systems: generally applied to wideband mobile services and applications.
3GPP	Third Generation Partnership Project: set up to expedite the development of open globally-accepted technical specifications for 3G.
3GPP2	Third Generation Partnership Project 2: Collaborative Third Generation (3G) telecommunications specification-setting project comprising North American and Asian interests on the development of the next generation CDMA2000 wireless communications.
3GSP	3G service provider. It is mobile operators that have 3G license to provide 3G services to customers.
802.11	IEEE standards for wireless LANs with specs for 1-2, 11 and 24 Mbps with access points typically covering 50-100 meters each.
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A/D	Analog-to-digital
AC	Alternating current
ACPR	Adjacent-channel power radio
ADC	Analog-to-digital converter
AGC	Automatic gain control
Air Interference	In mobile phones, the 'air interface' denotes the specification of the radio transmission between base station and mobile phone. It defines the frequency use (frequencies), the bandwidth of the individual radio channels (channels), the encoding methods used (W-CDMA, TD-CDMA, CDMA2000) and other quantities used by the radio technology.
ALU	Arithmetic logic unit
AMPS	Advanced mobile phone system: North American analog cellular phone system. Operates in the 800 MHz frequency band. AMPs is used in South America and Asia Pacific. It has not been deployed in Eastern Europe.
Analog	The technology which until recently was the norm for mobile phones, for example, 1G. It gives lower call quality and a major security risk.
ANSI	American National Standards Institution
Antenna	A device used for receiving or transmitting signals.
AODV	Ad-Hoc On Demand Distance Vector
ARIB	Association of Radio Industry and Businesses. A Japanese standard-setting body, organizational partner of the 3GPP and 3GPP2.
ARPU	Average revenue per customer
ASIC	Application-Specific Integrated Circuit
ASK	Amplifier Shift Keying
ASP	Application Service Provider
Asynchronous Transmission	A mode in which the sending and receiving serial hosts know where a character begins and ends because each byte is framed with additional bits, called a start bit and a stop bit. A start bit indicates the beginning of a new character; it is always 0 (zero). A stop bit marks the end of the character. It appears after the parity bit, if one is in use.
ATM	Asynchronous Transfer Mode: A high bandwidth, controlled-delay fixed-size packet switching and transmission system. Uses fixed-size packets also known as "cells"; ATM is often referred to as "cell relay." ATM will provide the basis for future broadband ISDN standards.
AWGN	Additive White Gaussian Noise
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BAN	Body Area Network: Wireless communication between various components attached to the body, such as data spectacles, earphones, microphones and sensors for medical applications and for work and leisure.
Bandwidth	Technical term for the capacity of a transmission channel. Because capacity, or even maximum speed, is generally dependent on the frequency range available, the 'bandwidth' (i.e., the width of a frequency band) usually has the same meaning as the maximum transmission speed available to a subscriber.
Base Station	The central radio transmitter/receiver that maintains communications with a mobile radiotelephone with a given range
BER	Bit Error Rate
Bluetooth	A global initiative by Ericsson, IBM, Intel, Nokia and Toshiba to set a standard for cable-free connectivity between mobile phones, mobile PCs, handheld computers and other peripherals. It will use short-range radio links in the 2.gGHZ Instrumentation Scientific and Medical (ISM) "free band".
BPS	Bits Per Second: Data transmission speed, the number of pieces of information transmitted per second.
BPSK	Binary Phase Shift Keying
Broadband	A classification of the information capacity or bandwidth of a communication channel. Broadband is generally taken to mean bandwidth higher than 2 Mbps.
Broadcast	The simultaneous transmission of data or voice to a number of stations.
BTS	Base Transceiver Station: Technical term for a mobile phone base station. A BTS contains the transmit and receive technology and also the aerials to supply a radio cell. Several BTSs are administered by a BSC (Base Station Controller), which is in turn under an MSC (Mobile Switching Center). Existing BSCs and BTSs can be extended for new radio technology to allow the network operator to reuse existing aerial sites for UMTS radio networks.
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Call Drop Rate	A dropped call rate out of completed sending calls (a sending call drop rate) or out of completed receiving calls (a receiving call drop rate).
Carrier	A licensed company (network operator) may market any number of communication services for voice and data. Carriers offer their services to both end-customers (private or business) and other carriers. In the latter case, the service simply consists of transport capacity for long-distance traffic. For example, local/regional network operators will buy transport capacity from carriers that operate on a global basis.
CCRR	Co-Channel Rejection Ratio
CDMA	Code Division Multiple Access: The code division technology was originally developed for military use over 30 years ago. CDMA is a multiple access technique, which uses code sequences as traffic channels within common radio channels - used for CDMA One (IS-95) air interface.
CDMA2000	Common name for IMT-2000 CDMA Multi-Carrier.
CDMA2000 1x	The first step in the evolution to 3G is CDMA2000 1X, which improves packet data transmission capabilities and speeds in the network, and also boosts voice capacity by nearly two times over today's CDMA capacities. Speed of up to 144kpps.
CDMA2000 1xEV-DO	(Evolution Data-Only). CDMA2000 1XEV represents the second step in the evolution of CDMA2000. Commercially launched early this year, offers data speeds of up to 2.4 Mbps on a separate 1.25 MHz carrier.
CDMA2000 1xEV-DV	(Evolution Data-Voice). CDMA2000 1XEV represents the second step in the evolution of CDMA2000. Recently approved by ITU as a 3G technology, will provide data and voice together on a single 1.25 MHz channel, with data rates of up to 4.8 Mbps.
CDMA2000 3X	3G technology which offers voice and data on a 5MHz carrier (or 3 times [3X] the 1.25 MHz carrier).
CDMAOne (IS-95)	CDMAOne is a digital mobile phone standard based on the CDMA principle, which is used in North America, Korea and Japan. CDMAOne uses frequency ranges around 800MHz and 1900MHz. For migration to third generation mobile telephony, CDMAOne networks can be upgraded to the CDMA2000 broadband standard.
CDPD	Cellular Digital Packet Data: A digital cellular standard used in some smart phones. Transmission rates are limited to 19.2 kbps.
Cell	The basic geographical unit of a cellular communications system. Service coverage of a given area is based on an interlocking network of cells, each with a radio base station (transmitter/receiver) at its center. The size of each cell is determined by the terrain and forecasted number of users.
Cellular	Circuit-switched voice telephone communications via cellular radio channels. The service area is divided into many cells and in each there is a base station handling the communications in that particular cell.
Cellphone	An American term for mobile phone.
CGI	Common Gateway Interface
Channels	An individual UMTS radio channel is defined in the IMT 2000 standard as having a bandwidth of 5 MHz. This means that an individual UMTS radio channel, for example, ranges from 1900 to 1905 MHz. How many radio channels a UMTS provider can make available to customers depends on which frequency spectrum has been won in the auctioning of UMTS mobile phone frequencies. Each radio channel can transport more than one connection. So that more than one subscriber can use the same channel, multiple access methods such as W-CDMA (FDD), TD-CDMA (TDD) or CDMA2000 are used for 3G networks. It nevertheless depends on the service profile of the connection how many connections per channel can be managed at the same time. It is also true that in the planning of the radio network, the effect of cellular respiration for CDMA should be considered.
Circuit switching	A method of communicating in which a dedicated communications path established between two devices through one or more intermediate switching nodes. Unlike packet switching, digital data are sent as a continuous stream of bits. Bandwidth is guaranteed, and delay is essentially limited to propagation time. The telephone system uses circuit switching.
CMOS	Complementary Metal-Oxide Semiconductor
Core Network	The switching part of the UMTS network. It provides call control and performs mobility and high-level security functions such as location updating and authentication. Core network includes a radio access network, terminals and applications.
Core Router	Core routers are switching computers used on the main connection links (backbone) of a network. These switching computers are particularly powerful, and specialize in the transfer of huge data volumes over the information highway.
COTS	Commercial Off-Of-The-Shelf
Coverage	The geographical reach of a mobile phone network or system.
CMRR	Common-Mode Rejection Ratio
CPE	Customer Premise Equipment
CSD	Circuit Switched Data: is the traditional technology used for the exchange of data. A circuit connection is made that is exclusively reserved for the individual’s use. Payment is then made in accordance with the duration of the connection. This can be inefficient, for example when connecting to the internet using WAP, as more time is spent reading the information than is spent exchanging data, however you continue to pay when you are reading. For corporate e-mail services however, applications have been developed where the user works “off line” and then only connects to the server to download and receive e-mails.
CTIA	Cellular Telecommunications Industry Association: A trade group representing cellular, PCS and enhanced specialized mobile radio carriers.
CW	Continuous Wave
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DC	Direct Current
DCS	Distributed Communications System or Digital Cellular System
DCT	Discrete Cosine Transfer
DDS	Direct Digital Synthesis
DECT	Digital European Cordless Telephone
Digital	The newest form of wireless communications that takes all voice transmissions and converts them to computer language (zeros and ones, or “binary” language) and then reconstructs them into the original voice format at the other end. More secure than its original sibling, analog, and also relatively impervious to static or fading signals.
Downlink	Technical term for data transmission in the direction from the network, the provider or the Internet provider to the subscriber. (The return channel is know as the uplink.)
Dropped Call	A wireless call that is unintentionally disconnected due to a system problem, lack of channel availability or dead spot in coverage.
DS-FDD	Direct Spread Frequency Division Duplex. European asynchronous W-CDMA FDD mode.
DSP	Digital Signal Processor
DS-WCDMA	Direct Sequence/Spread Wideband Code Division Multiple Access: A 3G radio interface for UMTS, also known as UTRA FDD or WCDMA-DS, and adopted as the IMT-DS 3G standard.
Dual band	Dual band mobile phones can work on networks that operate on different frequency bands. This is useful if you move between areas covered by different networks.
Dual mode	Dual mode mobile phones work on more than one network (for example, CDMA2000 and WCDMA).
DUT	Device Under Test
DVB	Digital Video Broadcasting: Harmonized digital TV that covers all media (satellite, cable and terrestrial). It supports Internet services at speed up to 6 Mbps and can be used on mobile devices.
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EEPROM	Electrically Erasable Programmable Read-Only Memory
EDGE	Enhanced Data rates for GSM Evolution. EDGE has been developed for those networks that didn't but a UMTS license and while it promises only about a third of the bandwidth, most UMTS services will also have a form using EDGE. Speed of upto 184kbps will be possible.
E-GPRS	Enhanced GPRS, another term for EDGE.
EMC	Electromagnetic Compatibility
EMI	Electromagnetic Interference
EPOC	A new operating system for mobile multimedia terminals developed by Symbian.
ESD	Electrostatic Discharge
ETSI	European Telecommunications Standards Institute: It specified the UMTS radio access with the creation of several working groups who set out to develop radio solutions presented by various compaines.
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FCC	Federal Communications Commission
FDD	Frequency Division Duplex: First variation of W-CDMA to be standardized and will appear commercially for the first time in Japan, mid 2001
FDM	Frequency-Division Multiplexing: A scheme in which numerous signals are combined for transmission on a single communications line or channel. Each signal is assigned a different frequency (subchannel) within the main channel.
FEM	Finite-Element Method
FET	Field-Effect Transistor
FFT	Fast Fourier Transform
FHSS	Frequency-Hopping, Spread Spectrum
FIFO	First-In, First-Out
FIR	Finite Impulse Response
Fixed Access	A terminal access to the network that users wired technology.
FOMA	Freedom of Mobile Multimedia Access: DoCoMo's brand name for 3G services, based on the W-CDMA format.
FPGA	Fine-Pitch Ball Grid Array
Frequency	Rate of signal oscillation in hertz, meaning the number of times the wave form repeats itself in second (measured in Hertz (Hz) where one Hz is one cycle per second). The frequencies band assigned to GSM is 900-1800 MHz. For 3G the band assigned are between 1885-2025 Mhz and 2110-2200 Mhz
FSK	Frequency Shift Keying
FWA	Fixed Wireless Access: An emerging terrestrial system for radio access in the 4GHz and 25GHz bands. It is the use of wireless technology to replace copper to connect subscribers to the telephone network and Internet.
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GaAs	Gallium Arsenide
Gain	Ratio of output power divided by input power (usually expressed in decibels or dB)
GaN	Gallium Nitride
Gb	Gigabit
GB	Gigabyte
GFSK	Gaussian Filtered Frequency Shift Keying
GHz	Gigahertz. One billion radio waves, or cycles, per second. Equal to one thousand Megahertz.
GMPCS	Global Mobile Personal Communications via Satellite: A group of proposals for advanced satellite based systems to extend the coverage afforded by terrestrial cellular systems and aiming to provide world-wide coverage of mobile services. Three projects called Iridium, Globalstar and ICO came out from it.
GMSK	Gaussian Minimum Shift Keying
GPIB	General Purpose Interface Bus
GPRS	General Packet Radio Service: GPRS is hailed as the 2.5 for mobile phones and will be with us from the beginning of 2001. GPIs will give you a permanent connection at about 50kbps or so to your mobile phone.
GPS	Global Positioning System: A worldwide radio-navigation system that was developed by the US. Department of Defense. In addition to military purposes it is widely used in marine, terrestrial navigation and location based services.
GSM	Global System for Mobile Communications: The mobile phone platform used in Europe and much of the rest of the world- though it is not mainstream in the USA. Dual band phones are capable of operating on other bandwidths aboard.
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Handoff	A function enabling communications to continue without gaps when a subscriber's hardware(telephone set or modem) is not within service area of a base station as a communication route is automatically transited and connected from one base station to another.
HBT	Heterojunction Bipolar Transistor
HDR	High Data Rate
HEMT	High Electron Mobility Transistor
HSCSD	High-Speed Circuit-Switched Data: In using HSCSD a permanent connection is established between the called and calling parties for the exchange of data. As it is circuit switched, HSCSD is more suited to applications such as videoconferencing and multimedia than 'bursty' type applications such as email, which is more suited to packet switched data.
HTTP	Hypertext Transfer Protocol
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I and Q	In-Phase And Quadrature
I/O	Input/Output
IC	Integrated Circuit
IF	Intermediate Frequency
IM	Intermodulation
iMode	Japanese network NTT DoCoMo has had a great deal of success with iMode, with the main advantage over WAP being that it is packet-switched network. Thus, it actually runs at the same speed of connection as WAP, but because the network is packet switched, it works considerably faster- and in color.
IMD	Intermodulation Distortion
IMT-2000	International Mobile Telecommunications 2000: The ITU initiative for a service that will provide radio access to the global telecommunications infrastructure, through both satellite and terrestrial systems, serving fixed and mobile users in public and private networks. In other words, third-generation services.
InP	Indium Phosphide
IP	Internet Protocol
IS-41	Inter-network connection protocol for connecting systems based on both analog and digital US standards.
IS-54	First-generation TDMA in 1991
IS-95	First-generation CDMA (CDMAONE).
IS-136	Second-generation TDMA in 1994. Also called "Digital AMPS" or "D-AMPS."
ISM	Industrial, Scientific and Medical
ITU	International Telecommunications Union. A United Nations organization responsible for co-ordinating global telecommunications activities, especially in the areas of standards setting, radio spectrum allocation and regulation.
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JEDED	Joint Electron Device Engineers Council
JSP	Java Server Pages
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kpbs	Kilobits per second, for example, data services for 2G operates at maximum speed of 9.6kbps.
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LAN	Local Area Network
LCC	Leadless Chip Carrier
LDMOS	Laterally Diffused Metal Oxide Silicon
Linearity	Describes how closely an output signal is to a perfectly scaled multiple of a corresponding input signal
LMDS	Local Multipoint Distribution Service
LNA	Low-Noise Amplifier
LO	Local Oscillator
Location-based Service	A service that tracks a cellular phone user's location within the mobile network and provides a variety of additional services: E911 service automatically notifies an emergency center of a user's location when he/she is in an urgent situation. Location Based Billing Service provides a discount rate when calling and receiving at a specific area. Tracking service grasps and manages the location of a person and an object. Location Based Information Service provides local information on the area near subscribers. All these services are made possible by a wide range of technology; GPS + Cell based (location)Tracking, Measuring Signal Attenuation (between a subscriber's hardware and a base station), Server Aided GPS System, Assisted GPS Tracking made of DSP Software based device and TOA(Time Of Arrival)/TDOA(Time Difference Of Arrival) Tracking. Server Aided GPS System was developed by SnapTrack, tested and verified at CDMA, GSM networks and is now under commercialization.
LOS	Line of Sight
LPF	Low-Pass Filter
LSI	Large Scale Integration
LTCC	Low-Temperature Co-Fired Ceramic
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MAN	Metropolitan Area Network: A regional computer or communication network spanning the area covered by an average to large city.
MC-CDMA	Multi-carrier Code Division Multiple Access: This 3G standard is an evolution of IS-95, combining three IS-95 carriers to form one wideband carrier. It is also known as cdma2000.
MDS	Multipoint Distribution Systems
MHz	Megahertz: One million radio waves, or cycles, per second. Equal to one thousand Kilohertz.
Micro Cells	In large cities, mobile phone operators are increasingly converting their networks to small cell structures (cells). Larger mobile phone cells with diameters from 10 to 20 miles are "macro cells". Radio cells in the mid- range (with a diameter of about one mile) are "micro cells". Even smaller are pico cells, which often only range a few hundred meters. The miniaturization of radio cells allows more subscribers to be supplied over a given area.
Microwave	The range in the electromagnetic spectrum from 300 MHz to 30 GHz (with corresponding wavelengths from 100 cm to 1 cm)
MMAC	Million Multiply Accumulate Operations
MMDS	Multichannel Multipoint Distribution Service
MMIC	Monolithic Microwave Integrated Circuit
Mobile radio network	Network using radio frequencies to connect mobiles to the fixed or mobile network.
MOSFET	Metal-Oxide Semiconductor Field-Effect Transistor
MOU	Minutes Of Use
MSPS	Million Samples Per Second
Multi-access portal	A service that provides Web access from a range of mobile, fixed and cable television devices.
MVNO	Mobile Virtual Network Operators: A company that buys network capacity from a network operator to offer its own branded mobile subscriptions and value-added services.
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Narrowband	A classification of the information capacity or bandwidth of a communication channel. Narrowband is generally taken to mean a bandwidth of 64kbit/s or less.
Node B	A 3G name for base station.
NRZ	Non-Return to Zero
NTC	Negative Temperature Coefficient
NTIA	National Telecommunications and Information Administration: The US federal government's spectrum management authority.
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OEM	Original Equipment Manufacturer
OFDM	Orthogonal frequency-division multiplexing: A method of digital modulation in which a signal is split into several narrowband channels at different frequencies. OFDM is similar to conventional frequency-division multiplexing (FDM). The difference lies in the way in which the signals are modulated and demodulated. Priority is given to minimizing the interference, or crosstalk, among the channels and symbols comprising the data stream. Less importance is placed on perfecting individual channels.
OHG	Operators Harmonization Group: A group of industry operators established to meet on harmonization issues. The group is working towards a way of harmonisation between CDMA2000 and W-CDMA.
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PA	Power Amplifier
Package	Leaded assembly (inside of which one or more die is mounted and connected) for use in larger circuits
PAN	Personal Area Network: Typically covers the few meters surrounding a user's workspace and provides the ability to synchronize computers, transfers files and gain access to local peripherals like printers and a range of pocket hardware. A technology like Bluetooth may enable wireless PAN.
PAR	Peak-to-Average Ratio
PCB	Printed Circuit Board
PCM	Pulse Code Modulation
PCMCIA	Personal Computer Memory Card Interface Association (now simply referred to as PC Card)
PCS	Personal Communications Services: Any of several types of wireless, voice and/or data communications systems, typically incorporating digital technology. PCS licenses are most often used to provide services similar to advanced cellular mobile or paging services. However, PCS can also be used to provide other wireless communications services, including services that allow people to place and receive communications while away from their home or office, as well as wireless communications to homes, office buildings and other fixed locations.
PDA	Personal Digital Assistant
PDC	Personal Digital Cellular: The digital wireless standard used in Japan. PDC uses TDMA air interface.
PECL	Positive Emitter-Coupled Logic
PGA	Pin Grid Array
PHEMT	Pseudomorphic High-Electron Mobility Transistor
Pico Cell	Very small cell in a mobile network for boosting capacity within buildings.
PIM	Personal Information Management: Functionality started with the Filofax, with all your personal data held in paper form in a single package. The personal organizer came along to store the data electronically with the ability to store the same information on your PC and synchronize the two. The same functionality is now finding its way into mobile phones, which also have the synchronization capability.
PLL	Phase-Locked Loop
Power Amplifier (PA)	A class of amplifiers that have the primary purpose of delivering high output power (usually accompanied by significant dissipated power)
PPM	Parts Per Million
PSK	Phase Shift Keying
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QAM	Quadrature Amplitude Modulation
QPSK	Quadrature Phase Shift Keying
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Radio interface	System enabling a mobile terminal to communicate with the network. Numerous discussions were held within ETSI in 1997 on the standardisation of a radio interface for UMTS. On 29 January 1998 the SMG committee adopted the UMTS Terrestrial Radio Access standard (UTRA). UTRA was adopted by the ITU in March 1999 as a radio interface standard for IMT 2000.
RAM	Random Access Memory
RF	Radio Frequency: The range in the electromagnetic spectrum loosley defined from 30 MHz to 3 GHz (with corresponding wavelengths from 1000 cm to 10 cm)
RF Power	A class of engineering -- circuits and signals primarily concerned with power levels ranging from a few watts to tens of thousands of watts in the RF spectrum.
RF Power Transistor	A discrete packaged transistor used in the amplification of RF power
RFI	Radio Frequency Interference
RFIC	Radio Frequency Integrated Circuit
RFID	Radio Frequency Identification
RMS	Root-Mean-Square
Roaming	Taking your phone aboard and be able to use it.
ROM	Read-Only Memory
RTT	Radio Transmission Technology: An air interface or standard for mobile phone transmissions.
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SAR	Successive Approximation Register
Satellite Mobile Phone	There are various satellite- supported mobile phone networks. The oldest network, "Inmarsat", requires large terminals. The "Iridium" network developed by Motorola and other companies came out with much smaller terminals, proved to be an economic failure, and is no longer in operation. In principle the ITU specifications for IMT-2000 also provide for optional satellite supply. They would come into question for UMTS supply in sparsely populated areas, deserts, or on the open seas. Because of the poor economic track record of satellite mobile phones to date, however, no concrete steps for satellite use in future UMTS networks are planned.
Satellite network	Network using radio frequencies relayed by satellite.
SDH	Synchronous Digital Hierarchy
SDMA	Space Division Multiple Access: A technique makes it possible to increase the capacity of a cellular mobile radio system by taking advantage of spatial separation between users. The base station does not transmit the signal to the entire cell area, as in conventional access techniques, but concentrates power in the direction of the mobile unit for which the signal is directed, reducing it in the directions where other units are present.
SDRAM/SORAM	Synchronous Dynamic Random Access Memory
Service provider	The mobile company that sends you bills and owns your signature on a contract.
SEU	Single-Event Upset
Si	Silicon
SiC	Silicon Carbide
SIM	Subscriber Identity Module
SIR	Serial Infrared
SMA	Standardization Management Activity
Smart Antenna	It solves the capacity problems of mature mobile cellular networks. By directing radio signals to an intended target rather than broadcasting throughout the entire cell area, they increase the network's capacity. The more elaborate smart antenna systems can communicate with multiple mobile stations in the same cell, on the same channel, thereby exploiting their spatial separation.
SMD	Short Message Delivery
SMR	Specialized Mobile Radio
SMS	Short Messaging Service: Popularly known as "text messages". Analysis said it will be the main revenue generator for 3G operators.
SMT	Surface-Mount Technology or Surface-Mount Toroidal
SNR	Signal-to-Noise Ratio
Soft handoff	In wireless communication, soft handoff refers to the overlapping of repeater coverage zones, so that every cell phone set is always well within range of at least one base station. In some cases, mobile sets transmit signals to, and receive signals from, more than one repeater at a time.
Software radio	An emerging technology which allows network operators to simultaneously support multiple communications standards (GSM, CDMA, W-CDMA, 3G etc) on the one network infrastructure without begin bound by a particular standard.
SOIC	Small-Outline Integrated Circuit
SONET	Synchronous Optical Network
SPDT	Single-Pole Double-Throw
Spectrum	The range of electromagnetic radio frequencies used in the transmission of sound, data and television.
SSPA	Solid State Power Amplifier
Streaming Media	Technical term for digital audio or video transmissions via the Internet. The sound and image data are sent as a data stream to the subscriber, hence the term "streaming". A variety of deferred data streams can be output from a streaming media server on the Net. Each receiver can thus receive the same content deferred. Normally, a packet- switched or asymmetric transmission method is used.
S-UMTS	Satellite UMTS: A satellite-based system that, independently of the terrestrial mobile networks and can provide some of the ground based UMTS system's capabilities.
Switching	On a telecommunications network, switching means routing traffic by setting up temporary connections between two or more network points. This is done by devices located at different locations on the network, called switches (or exchanges). The basic structure of a telecommunications network therefore comprises transmission media, interconnected by exchanges. "Packet" and "circuit" switching are two techniques used by telecommunications networks. The first is used by IP networks, and the second by traditional networks (PSTN).
Synchronous	Type of transmission in which the transmission and reception of all data is synchronized by a common clock and the data is usually transmitted in blocks rather than individual characters. Can also mean that the data stream has the same capacity in both directions.
Synchronous mode	Standard for data transmission - data is transferred without start and stop bits together with a clock signal to synchronize the receiver. This mode gives higher data throughput than asynchronous mode, but can be less secure.
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TCP	Transmission Control Protocol
TCXO	Temperature-Controlled Oscillator
TDD	Time Division Duplex: This will be the second variation of W-CDMA which will be standardized towards the end of 2001, to appear commercially towards the end of 2003. This version is especially suited to indoor environments where there is a need for high traffic density.
TDM	Time Division Multiplexing: A scheme in which numerous signals are combined for transmission on a single communications line or channel. Each signal is broken up into many segments, each having very short duration.
TDMA	Time-Division Multiple Access: TDMA services can be delivered in the 800 MHz and 1900 MHz frequency bands.
TD-SCDMA	Siemens developed this special transmission method for UMTS together with the China Academy of Telecommunications Technology (CATT). TD-SCDMA is to be used for setting up UMTS mobile phone networks in China. It combines the SCDMA technique developed by CATT with the TD-CDMA method proposed by Siemens and other manufacturers. The S in 'SCDMA' refers to the special synchronous mode: All radio base stations transmit and receive synchronously: they prevent unavoidably occurring feedback interferences with asynchronous radio methods. An advantage of the TD-SCDMA technique is that it is also suitable for unpaired frequency ranges (frequencies, duplex separation).
Terminal	A terminal can be a notebook computer, PC, TV, phone, mobile device, appliance etc.
TETRA	Trans European Trunked Radio
Triple-band	It means phone understand the American 1900MHz frequency band as well as the European 900MHz and 1800MHz.
TSOP	Thin Small Outline Package
TTL	Transistor-Transistor Logic
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UART	Universal Asynchronous Receiver Transmitter
UDP	User Datagram Protocol
UICC	USIM Integrated Circuit Card. The UICC is the chip card used in mobile terminals in 3G telecom networks-Systems. The UICC is an essential component for UMTS, just as the SIM is for GSM. Extending the concept of the SIM card, the UICC contains the USIM application and also provides a platform for other IC Card applications. It ensures the integrity and security of all kinds of personal data, enabling secure support for all kinds of multi-application schemes.
UMTS	Universal Mobile Telecommunications Service: This is almost universally subscribed to standard for the third generation and is generally based on W-CDMA (Wideband Code Division Multiple Access). UMTS will launch in 2002, but full services for the general public will not arrive until around 2005. It promises a permanent internet connection of at least 384kbps and up to about 2mbps, combined with highly integrated devices and a super-fast back end.
UNII	Unlicensed National Information Infrastructure
Uplink	Technical term for data transmission in the direction from the subscriber to the network, or rather back to the provider or Internet provider. Also called back channel . The opposite transmission direction, the 'transmission channel', is called the 'uplink' in technical jargon.
UTRA	UMTS Terrestrial Radio Access: A term use for UMTS radio access solution, applied to W-CDMA and TD-CDMA .
UTRAN	UMTS Terrestrial Radio Access Network: A term describing the Radio Network Controllers and Node Base stations of a UMTS network. The UMTS network, built around an IP-optimized core network carrying all traffic types. UTRAN will support both UTRA Frequency Division Duplex (FDD) and Time Division Duplex (TDD) radio interfaces allowing flexible, high-bandwidth support, and will be connected to an IP-optimized core network through a UTRAN Gateway.
UWC-136	Universal Wireless Communications 136. Proposed by the TIA and adopted by the ITU for 3G, UWC-136 is a 3G TDMA standard that allows the US TDMA community to migrate from 1st (IS-136) to 3rd (UWC-136) generation systems. The standard uses a wideband TDMA technique.
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VCO	Voltage-Controlled Oscillator
VCSEL	Vertical Cavity Surface-Emitting Laser
VCXO	Voltage-Controlled Crystal Oscillator
VOD	Video On Demand: A service that allows subscribers to watch programs at the time when they want
VOFDM	Vector Orthogonal Frequency Division Multiplexing
VSAT	Very Small Aperture Terminal (Satellite Service)
VSWR	Voltage Standing Wave Radio
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WAN	Wide Area Network: A general term referring to a large network spanning a country or around the world. The Internet is a WAN. A public mobile communication system is a WAN.
WAP	Wireless Application Protocol: A technology designed to provide users of mobile terminals with limited access to the Internet. It offers information in text form on the screen of your phones, but it's hardly the World Wide Web.
W-CDMA	Wideband Code-Division Multiple Access: One of two 3G standards that makes use of a wider spectrum than CDMA and therefore can transmit and receive information for faster and more efficiently. Co-developed by NTT DoCoMo, it is being backed by most European mobile operators and is expected to compete with cdma2000 to be the de facto 3G standard.
Wideband	A classification of the information capacity or bandwidth of a communication channel. Wideband is generally taken to mean a bandwith between 64kbits/s and 2Mbit/s.
Wireless Access	A terminal access to the network that uses wireless technology.
WLAN	Wireless Local Area Network
WMAN	Wireless Metropolitan Area Network: A regional wireless computer or communication network spanning the area covered by an average to large city.
WML	Wireless Markup Language: A markup language developed specifically for wireless applications. WML is based on XML.
W-TDMA	Wideband-Time Division Multiple Access: A technique based on time division transmission which is similar to that used by GSM but provides a much higher transmission rate. It was submitted as a solution for UMTS radio interface, but was rejected.