1G
The first generation of analogue mobile phone technologies including AMPS, TACS and NMT.

 2G
The second generation of digital mobile phone technologies including GSM, CDMA IS-95 and D-AMPS IS-136.

 2.5G
The enhancement of GSM which includes technologies such as GPRS.

 3G
The third generation of mobile phone technologies covered by the ITU IMT-2000 family.

 3GPP
The 3rd Generation Partnership Project, a grouping of international standards bodies, operators and vendors with the responsibility of standardising the WCDMA based members of the IMT-2000 family.

 3GPP2
The counterpart of 3GPP with responsibility for standardising the CDMA2000-based members of the IMT-2000 family. 3GPP2 is spearheaded by ANSI.

 8PSK
Octantal Phase Shift Keying.

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 A5/1/2/3/8X
Encryption algorithms for GSM networks.

 AAL
ATM Adaptation Layer.

 ABR
Available Bit Rate.

 A-bis
Interface between the BSC and BTS in a GSM network.

 AB
Access Burst; used for random access and characterised by a longer guard period to allow for burst transmission from a MS that does not know the correct timing advance when first contacting a network.

 ACTE
Approvals Committee for Terminal Equipment.

 ACTS
Advanced Communications Technologies and Services – a European technology initiative.

 ACU
Antenna Combining Unit.

 ADPCM
Adaptive Differential Pulse Code Modulation; a form of voice compression that typically uses 32kbit/s.

 AFC
Automatic Frequency Control.

 AGCH
Access Grant Channel; downlink only, BTS allocates a TCH or SDCCH to the MS, allowing it access to the network.

 Air interface
In a mobile phone network, the radio transmission path between the base station and the mobile terminal.

 A-interface
Interface between the MSC and BSS in a GSM network.

 AM
Amplitude Modulation.

 AMPS
Advanced Mobile Phone System, the analogue mobile phone technology used in North and South America and in around 35 other countries. Operates in the 800MHz band using FDMA technology.

 AMR
Adaptive Multi-Rate codec. Developed in 1999 for use in GSM networks, the AMR
has been adopted by 3GPP for 3G.

 Analogue
The representation of information by a continuously variable physical quantity such as voltage.

 ANSI
American National Standards Institute. An non-profit making US organisation which does not carry out standardisation work but reviews the work of standards bodies and assigns them category codes and numbers.

 ANSI-136
See D-AMPS.

 API
Application Program Interface.

 ARIB
Association of Radio Industries and Businesses. An organisation established by Japan’s Ministry of Posts and Communications to act as the standardisation authority for radio communication and broadcasting.

 ARPU
Average Revenue Per User.

 ASCII
American Standard Code for Information Interchange.

 ASIC
Application Specific Integrated Circuit.

 ASP
Application Service Provider.

 Asymmetric Transmission
Data transmissions where the traffic from the network to the subscriber is at a higher rate than the traffic from the subscriber to the network.

 A-TDMA
Advanced Time Division Multiple Access.

 ATM
Asynchronous Transfer Mode; a multiplexed information transfer and switching method in which the data is organised into fixed length 53-octet cells and transmitted according to each application’s instantaneous need.

 AUC
Authentication Centre; the element within a GSM network which generates the parameters for subscriber authentication.

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 Bandwidth
A term meaning both the width of a transmission channel in terms of Hertz and the maximum transmission speed in bits per second that it will support.

 BCH
Broadcast Channels; carry only downlink information and are mainly responsible for synchronisation and frequency correction (BCCH, FCCH and SCH).

 BCCH
Broadcast Control Channel; the logical channel used in cellular networks to broadcast signalling and control information to all mobile phones within the network.

 B-CDMA
Broadband Code Division Multiple Access.

 B-ISDN
Broadband ISDN.

 BER
Bit Error Rate; the percentage of received bits in error compared to the total number of bits received.

 BERT
Bit Error Rate Test.

 Bit
A bit is the smallest unit of information technology. As bits are made up using the binary number system, all multiples of bits must be powers of two i.e. a kilobit is actually 1024 bits and a megabit 1048576 bits. Transmission speeds are given in bits per second (bit/s).

 Bluetooth
A low power, short range wireless technology designed to provide a replacement for the serial cable. Operating in the 2.4GHz ISM band, Bluetooth can connect a wide range of personal, professional and domestic devices such a laptop computers and mobile phones together wirelessly.

 BHCA
Busy Hour Call Attempts; the number of call attempts made during a network’s busiest hour of the day.

 BSC
Base Station Controller; the network entity controlling a number of Base Transceiver Stations.

 BSS
Base Station System/Subsystem.

 BTS
Base Transceiver Station; the network entity which communicates with the mobile station.

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 CAI
Common Air Interface; a standard developed for the UK’s public CT2 networks which enabled the same handset to be used on different networks.

 CAMEL
Customised Application for Mobile network Enhanced Logic; an IN feature in GSM networks that enables users to carry personal services with them when roaming into other networks that support CAMEL.

 CSE
CAMEL Service Environment.

 Capacity
A measure of a cellular network’s ability to support simultaneous calls.

 CB
Cell Broadcast.

 CC
Call Control; manages call connections.

 CCB
Customer Care and Billing.

 CCCH
Common Control Channels; a group of uplink and downlink channels between the MS and the BTS (see PCH, AGCH and RACH).

 CCS7
Common Channel Signalling No. 7.

 CDMA
Code Division Multiple Access; also known as spread spectrum, CDMA cellular systems utilise a single frequency band for all traffic, differentiating the individual transmissions by assigning them unique codes before transmission. There are a number of variants of CDMA (see W-CDMA, B-CDMA, TD-SCDMA et al).

 CDMAone
The first commercial CDMA cellular system; deployed in North America and Korea; also known as IS-95.

 CDMA2000
A member of the IMT-2000 3G family; backwardly compatible with cdmaOne.

 CDMA 1X
The first generation of cdma2000; the standardisation process indicated that there would be CDMA 2X and CDMA 3X but this no longer appears likely.

 CDMA 1X EV-DO
A variant of CDMA 1X which delivers data only.

 CDPD
Cellular Digital Packet Data; a packet switched data service largely deployed in the USA. The service uses idle analogue channels to carry the packetised information.

 CDPSK
Coherent Differential Phase Shift Keying.

 CDR
Call Detail Records; the record made within the cellular network of all details of both incoming and outgoing calls made by subscribers, The CDR is passed to the billing system for action.

 Cell
The area covered by a cellular base station. A cell site may sectorise its antennas to service several cells from one locationCell site. The facility housing the transmitters/receivers, the antennas and associated equipment.

 Cell splitting
The process of converting a single cell to multiple cells by sectorising the antennas in the cell site or constructing additional cells within a cell site.

 CELP
Code Excited Linear Prediction; an analogue to digital voice coding scheme, there are a number of variants used in cellular systems.

 CEPT
Conference of European Posts and Telecommunications. A organisation of national posts, telegraphs and telephone administrations. Until 1988, when this work was take over by ETSI, the main European body for telecommunications standardisation. CEPT established the original GSM standardisation group.

 CF
Call Forwarding.

 CI
Carrier to Interference ratio.

 CIBER
Cellular Intercarrier Billing Exchange Roamer Record.

 CID
Caller Identification.

 Circuit switching
A method used in telecommunications where a temporary dedicated circuit of constant bandwidth is established between two distant endpoints in a network. Mainly used for voice traffic; the opposite of packet switching.

 CLID
Calling Line Identification.

 CLIP
Calling Line Identification Presentation.

 CLIR
Calling Line Identification Restriction.

 CM
Connection Management; is used to set up, maintain and take down call connections.

 CMOS
Complementary Metal Oxide Substrate.

 Codec
A word formed by combining coder and decoder the codec is a device which encodes and decodes signals. The voice codec in a cellular network converts voice signals into and back from bit strings. In GSM networks, in addition to the standard voice codec, it is possible to implement Half Rate (HR) codecs and Enhanced Full Rate (EFR) codecs.

 Control signal
A signal sent to a cellular phone from a base station or vice versa which carries information essential to the call but not including the audio portion of a conversation.

 CPE
Customer Premises Equipment; all the equipment on the end user’s side of the network interface.

 CPU
Central Processing Unit.

 CRC
Cyclic Redundancy Check.

 CRM
Customer Relationship Management.

 CSS
Customer Support System.

 CT
Cordless Telephony.

 CT0
Zero generation cordless telephony; the earliest domestic cordless phones which used analogue technology and which had severe limitations in terms of range and security.

 CT1
First generation cordless telephony; Improved analogue phones with greater range and security; a number of European nations produced CT1 standards.

 CT2
Second generation cordless telephony; Using digital technology CT2 phones offered greater range, improved security and a wide range of new functionalities. Used in both domestic and cordless PABX deployments, CT2 was standardised as an interim ETS but was overwhelmed by DECT.

 CT2-CAI
Second generation cordless telephony-common air interface.

 CTA
Cordless Terminal Adaptor; a DECT term.

 CTM
Cordless Terminal Mobility.

 CTR
Common Technical Regulation; part of the ETSI standardisation process.

 CUG
Closed User Group.

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 D/A
Digital to Analogue conversion.

 DAC
Digital to Analogue Convertor.

 DAMA
Demand Assigned Multiple Access.

 D-AMPS
Digital AMPS, a US wireless standard also known as IS-136.

 DAN
DECT Access Node.

 DCA
Dynamic Channel Assignment.

 DCCH
Dedicated Control Channels; responsible for roaming, handovers, encryption etc. (See SDCCH, SACCH and FACCH).

 DCE
Data Communications Equipment.

 DCH
Data Clearing House.

 DCPSK
Differentially Coherent Phase Shift Keying.

 DCS1800
Digital Cellular System at 1800MHz, now known as GSM1800.

 DECT
Digitally Enhanced Cordless Telecommunications system, a second generation digital cordless technology standardised by ETSI.

 DEPSK
Differential Encoded Phase Shift Keying.

 DES
Digital Encryption Standard.

 DFSK
Double Frequency Shift Keying.

 Digital
a method of representing information as numbers with discrete values; usually expressed as a sequence of bits.

 DPCM
Differential Pulse Code Modulation.

 DPSK
Digital Phase Shift Keying.

 DQPSK
Digital Quadrature Phase Shift Keying.

 DS-CDMA
Direct Sequence CDMA.

 DSP
Digital Signal Processing.

 DSRR
Digital Short Range Radio; a UK standard for a low power, short range radio system designed for small voice and data networks.

 DTE
Data Terminal Equipment.

 DTMF
Dual Tone MultiFrequency; better know as Touch Tone. The tones generated by touching the keys on the phone are used for a variety of purposes including voice mail systems and voice messaging.

 DTX
Discontinuous Transmission.

 Dual Band
The capability of GSM infrastructure elements and handsets to work across both the 900MHz and 1800MHz bands. The capability to seamlessly handover between the two bands offers operators major capacity gains.

 DB
Dummy Burst; transmitted as a filler in unused timeslots of the carrier.

 Duplex
The wireless technique where one frequency band is used for traffic from the network to the subscriber (the downlink) and another, widely separated, band is used for traffic from the subscriber to the network (the uplink).

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 EDGE
Enhanced Data rates for GSM Evolution; effectively the final stage in the evolution of the GSM standard, EDGE uses a new modulation schema to enable theoretical data speeds of up to 384kbit/s within the existing GSM spectrum. An alternative upgrade path towards 3G services for operators, such as those in the USA, without access to new spectrum. Also known as Enhanced GPRS (E-GPRS).

 EEPROM
Electrically Erasable Programmable Read Only Memory.

 EFR
Enhanced Full Rate; a alternative voice codec that provides improved voice quality in a GSM network (see codec).

 EFT
Electronic Funds Transfer.

 EGSM
Extended (frequency range) GSM.

 EIR
Equipment Identity Register; a database that contains a list of all valid mobile stations within a network based on their IMEI.

 EIRP
Effective Isotropic Radiated Power.

 EPOC
The mobile phone operating system developed by Symbian. Derived from epoch-the beginning of an era-EPOC is a 32-bit operating environment which comprises a suite of applications, customisable user interfaces, connectivity options and a range of development tools.

 EPROM
Erasable Programmable Read Only Memory.

 Erlang
A dimensionless unit of average traffic density in a telecommunications network.

 ERMES
Enhanced Radio Messaging System; a paging technology developed by ETSI which was intended to allow users to roam throughout Europe. Adopted by a number of European and Middle Eastern countries, ERMES, like paging in general, was overtaken by the ubiquity of GSM.

 ERO
European Radiocommunications Office.

 ERP
Effective Radiated Power.

 ESMR
Enhanced Special Mobile Radio; a US PMR variant (see SMR).

 ESN
Electronic Serial Number; a 32-bit number that uniquely identifies a mobile phone.

 ESPRIT
European Strategic Programme for Research and Development in Information Technology.

 ETACS
Extended TACS; the extension of TACS by the addition of new frequencies.

 ETS
European Telecommunications Standard.

 ETSI
European Telecommunications Standards Institute: The European group responsible for defining telecommunications standards.

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 FACCH
Fast Associated Control Channel; similar to the SDCCH but used in parallel for operation of the TCH. If the data rate of the SACCH is insufficient borrowing mode is used.

 FB
Frequency Correction Burst; used for frequency synchronisation of the mobile.

 FCC
Federal Communications Commission; the US regulatory body for telecommunications.

 FCCH
Frequency Correction Channel; downlink only, correction of MS frequencies, transmission of frequency standard to MS etc.

 FDD
Frequency Division Duplex; a radio technique which uses paired spectrum; UMTS has an FDD element.

 FDMA
Frequency Division Multiple Access-a transmission technique where the assigned frequency band for a network is divided into sub-bands which are allocated to a subscriber for the duration of their calls.

 FEC
Forward Error Correction.

 FH
Frequency Hopping.

 FH-CDMA
Frequency Hopping CDMA.

 FMC
Fixed Mobile Convergence.

 FMI
Fixed Mobile Integration.

 FPLMTS
Future Public Land Mobile Telecommunications System, the original title of the ITU’s third generation concept now known as IMT-2000.

 FRA
Fixed Radio Access; see WLL.

 FSDPSK
Filtered Symmetric Differential Phase Shift Keying.

 FSK
Frequency Shift Keying; a method of using frequency modulation to send digital information.

 FSOQ
Frequency Shift Offset Quadrature Modulation.

 FSS
Fixed Satellite ServiceGb.
The interface between the PCU and the SGSN in a GSM/GPRS network.

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 Gc
The interface between the GGSN and the HLR in a GSM/GPRS network.

 Gd
The interface between the SGSN and the SMSC in a GSM/GPRS network.

 Gf
The interface between the SGSN and the EIR in a GSM/GPRS network.

 Gi
The interface between the GGSN and the Internet in a GPRS network.

 Gn
The interface between the GGSN and the SGSN in a GPRS network.

 Gp
The interfaces between the GGSN/SGSN and the Border Gateway in a GPRS network.

 Gr
The interface between the SGSN and the HLR in a GPRS network.

 Gs
The interface between the SGSN and the MSC in a GSM/GPRS network.

 GAIT
GSM/ANSI 136 Interoperability Committee.

 GAP
Generic Access Profile; a DECT term.

 Gbit/s
A unit of data transmission rate equal to one billion bits per second.

 GMSC
Gateway Mobile Services Switching Centre; the gateway between two networks.

 GCF
Global Certification Forum.

 Geostationary
Refers to a satellite in equatorial orbit above the earth which appears from the surface to be stationary.

 GERAN
GSM-EDGE Radio Access Network; the name for the evolution of GSM towards 3G based on EDGE.

 GGRF
GSM Global Roaming Forum.

 GGSN
Gateway GPRS Support Node; the gateway between a cellular network and a IP network.

 GHz
A unit of frequency equal to one billion Hertz per second.

 GMPCS
Global Mobile Personal Communications by Satellite.

 GMSK
Gaussian filtered Minimum Shift Keying; a refinement of FSK which minimises adjacent channel interference.

 GPRS
General Packet Radio Service; standardised as part of GSM Phase 2+, GPRS represents the first implementation of packet switching within GSM, which is a circuit switched technology. GPRS offers theoretical data speeds of up to 115kbit/s using multislot techniques. GPRS is an essential precursor for 3G as it introduces the packet switched core required for UMTS.

 GPS
Global Positioning System; a location system based on a constellation of US Department of Defence satellites. Depending on the number of satellites visible to the user can provide accuracies down to tens of metres. Now being incorporated as a key feature in an increasing number of handsets.

 GRX
GPRS Roaming Exchange.

 GSM
Global System for Mobile communications, the second generation digital technology originally developed for Europe but which now has in excess of 71 per cent of the world market. Initially developed for operation in the 900MHz band and subsequently modified for the 850, 1800 and 1900MHz bands. GSM originally stood for Groupe Speciale Mobile, the CEPT committee which began the GSM standardisation process.

 GSM MoU
The GSM Memorandum of Understanding, an agreement signed between all the major European operators to work together to promote GSM. The precursor of the GSM Association.

 GSM-R
GSM-Railway, A variant of GSM designed to meet the special communications needs of international train operators.

 Handoff
The transfer of control of a cellular phone call in progress from one cell to another, without any discontinuity.

 Hands-free
The operation of a cellular phone without using the handset; usually installed in vehicles.

 HCS
Hierarchical Cell Structure; the architecture of a multi-layered cellular network where subscribers are handed over from the macro to the micro to the pico layer depending on the current network capacity and the needs of the subscriber.

 HDLC
High level Data Link Control.

 HIPERLAN
High Performance Radio Local Access Network; a wireless local area network being standardised by ETSI (Also HIPERLAN2).

 HLR
Home Location Register; the database within a GSM network which stores all the subscriber data. An important element in the roaming process.

 HSCSD
High Speed Circuit Switched Data; a special mode in GSM networks which provides higher data throughput By cocatenating a number of timeslots, each delivering 14.4kbit/s, much higher data speeds can be achieved.

 HSPSD
High Speed Packet Switched DataIub
The interface between the Node B and the RNC in a UMTS network.

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 Iur
The interface between RNCs in a UMTS network.

 Iups
The connection between the RNC and the packet switched network in a GSM/GPRS/UMTS network.

 Iucs
The connection between the RNC and the circuit switched network in a GSM/GPRS/
UMTS network.

 I-ETS
Interim European Telecommunications Standard.

 I-mode
A service developed by Japanese operator NTT DoCoMo, I-mode delivers a huge range of services to subscribers and has proved enormously popular with some 30 million regular users. The revenue sharing model used for I-mode is being adopted by other operators as the basis for the new services enabled by GPRS and 3G.

 IMEI
International Mobile Equipment Identity.

 IMSI
International Mobile Subscriber Identity; an internal subscriber identity used only by the network.

 IMT-2000
The family of third generation technologies approved by the ITU. There are five members of the family: IMT-DS, a direct sequence WCDMA FDD solution IMT-TC, a WCDMA TDD solution IMT-MC, a multicarrier solution developed from cdma2000 IMT-SC, a single carrier solution developed from IS-136/UWC-136 IMT-FT, a TDMA/TDD solution derived from DECT.

 IN
Intelligent Network.

 INAP
Intelligent Network Application Part.

 Internet
A loose confederation of autonomous databases and networks. Originally developed for academic use the Internet is now a global structure of millions of sites accessible by anyone.

 Intranet
A private network which utilises the same techniques as the Internet but is accessible only by authorised users.

 IP
Internet Protocol.

 IPR
Intellectual Property Rights.

 IPv6
The next generation of IP addressing designed to replace the current system IPv4 which uses a 32 bit address code which limits the number of possible addresses. IPv6 uses a 128 bit code ensuring that the possible number of IP addresses will be virtually limitless.

 IrDA
Infra red Data Association.

 Iridium
A low earth orbit satellite communications system developed initially by Motorola.

 IS-54
The first evolution in the USA from analogue to digital technology. Used a hybrid of analogue and digital technology, superseded by IS-136.

 IS-95
Cellular standard know also as cdmaOne.

 IS-136
Cellular standard also known as TDMA or D-AMPS.

 ISDN
Integrated Services Digital Network.

 ISO
International Standards Organisation.

 ISP
Internet Service Provider.

 ITU
International Telecommunications Union.

 ITU-R
ITU Telecommunications Radio Sector.

 ITU-T
ITU Telecommunications Standardisation Sector.

 IWF
Interworking Function.

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 Java
A programming language developed by Sun Microsystems Java is characterised by the fact that programs written in Java do not rely on an operating system.

 JPEG
Joint Photographic Experts Group.

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 LAN
Local Area Network.

 LANS
Local Area Network Services.

 LAP
Link Access Protocol.

 LEO
Low Earth Orbit; refers to satellites which orbit the Earth at around 1,000 kilometres.

 LMSS
Land Mobile Satellite Service.

 LOS
Line of Sight.

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 MAC
Media Access Control; the lower sublayer of the OSI system.

 MAN
Metropolitan Area Network.

 MAP
Mobile Application Part.

 Mbit/s
Megabit: a unit of data transmission speed equal to one million bits per second.

 MHz
Megahertz; a unit of frequency equal to one million Hertz.

 MCPA
Multi Carrier Power Amplifier.

 MeXe
Mobile Execution Environment; likely to be based on Java, MeXe enables WAP-enabled devices to offer a wider range of features with greater security and flexibility, as well as greater control of telephony features.

 MFSK
Multiple Frequency Shift Keying.

 MMI
Man Machine Interface.

 MMS
Multimedia Messaging Service; an evolution of SMS, MMS goes beyond text messaging offering various kinds of multimedia content including images, audio and video clips.

 MMSK
Modified Minimum Shift Keying.

 MNO
Mobile Network Operator.

 Modulation
The process of imposing an information signal on a carrier. This can be done by changing the amplitude (AM), the frequency (FM) or the phase, or any combination of these.

 MoU
Memorandum of Understanding-see GSM MoU.

 MPEG
Motion Picture Experts Group; MPEG4 is a technology for compressing voice and video so that the information can be transmitted over normally difficult links such as mobile radio.

 MS
Mobile Station.

 MSC
Mobile Switching Centre; the switching centre of a mobile phone network, the MSC has interfaces to the BSCs, HLR, VLR and other MSCs.

 MSISDN
Mobile Station International ISDN Number.

 MSK
Minimum Shift Keying; Another term for FFSK.

 Multiplexing
A telecommunications technique where several channels can be combined to share the same transmission medium. The most common forms are Time Division Multiplexing (TDM) and Frequency Division Multiplexing (FDM).

 MVPN
Mobile Virtual Private Network.

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 N-AMPS
Narrowband AMPS.

 NB
Normal Burst; used to carry traffic and control channels except RACH.

 NET
Norme Europeenne de Telecommunications.

 NMT
Nordic Mobile Telephone system; an analogue cellular technology deployed in the Nordic countries in the late 1970’s; variations were also deployed in the Benelux countries and in Russia. NMT operated in the 450 and 900MHz bands and was the first technology to offer international roaming, albeit only in the Nordic countries.

 Node B
The element in a UMTS network which interfaces with the mobile station, analogous to a BTS in a GSM network.

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 OTA
Over the air activation (of services and tariff changes).

 O&M
Operations and Maintenance.

 OMC
Operations and Maintenance Centre.

 OMC-R
The radio OMC.

 OMC-S
The switching OMC.

 OSI
Open Systems Interconnection; a seven layer model for protocols defined by ISO.

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 PACS
Personal Access Communication System; a digital cordless technology developed initially by Bell Labs in the US, PACS was designed to compete with DECT.

 Packet switching
A communication system wherein the information is transmitted in packets of a set size. These packets have address headers and find their way to their destination by the most efficient route through the network. Compared to circuit switching where a connection is occupied until the traffic exchange is completed, packet switching offers considerable efficiencies as connections can be used by a number of users simultaneously.

 PAMR
Public Access Mobile Radio; Commercial service using trunking techniques in which multiple groups of users can set up their own closed systems within a shared public network.

 PAP
Public Access Profile; a DECT term.

 PCH
Paging Channel; downlink only, the MS is informed of incoming calls by the BTS via the PCH.

 PCM
Pulse Code Modulation; the standard digital voice format at 64kbit/s.

 PCMCIA
Personal Computer Memory Card Interface Association the body responsible for defining the standards and formats for memory expansion cards for laptop computers and PDAs. Now extended to cover cards for mobile phones.

 PCN
Personal Communications Network; a designation initially used in the UK to refer to networks operating in the 1800MHz band (see also DCS1800). No longer in use.

 PCS 1900
Personal Communications Systems 1900MHz; the terminology used in the US to describe the new digital networks being deployed in the 1900MHz band; rarely used today.

 PCU
Packet Control Unit; an element in a GPRS/UMTS network.

 PDA
Personal Digital Assistant.

 PDC
Personal Digital Communications; a digital cellular technology developed and deployed uniquely in Japan. A TDMA technology, PDC is incompatible with any other digital cellular standard.

 PEDC
Pan European Digital Communications; A designation occasionally used in the early 1990’s to describe GSM. No longer in use.

 Penetration
The percentage of the total population which owns a mobile phone.

 PHS / PHP
Personal HandyPhone System/Phone; a digital cordless technology developed in Japan which achieved great success. Deployed by NTT DoCoMo and other Japanese operators PHS offered two-way communications, data services and Internet access and eventually won some 28 million customers. Now in decline as cellular’s wide area capabilities offer better service.

 PIN
Personal Identifier Number.

 PKI
Public Key Infrastructure.

 PLMN
Public Land Mobile Network; any cellular operator’s network.

 PMR
Private Mobile Radiocommunications; two-way radio technology widely used for despatch and delivery services, taxi companies and the like. See TETRA.

 POCSAG
Post Office Code Standardisation Group; a now defunct industry grouping which standardised pager addressing systems.

 PoP
Points of Presence; a method of measuring the value of a cellular licence; the approximate number of potential customers within a geographical area.

 POTS
Plain Old Telephone Service.

 PROM
Programmable Read Only Memory.

 PSK
Phase Shift Keying.

 PSRCP
Public Safety Radio Communications Project; an initiative by the UK Government to standardise all emergency services communications on to a single digital technology (see TETRA).

 PSDN
Public Switched Data Network.

 PSPDN
Public Switched Packet Data Network.

 PSTN
Public Switched Telephone Network.

 PSU
Power Supply Unit.

 PTO
Public Telecommunication Operator.

 PTT
Posts, Telephone and Telegraph Administration.

 PTT
Push-to-Talk; a feature of PMR systems.

 PWT
Personal Wireless Telecommunications; a variant of DECT developed for use in the USA.

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 QAM
Quadrature Amplitude Modulation.

 QAPSK
Quadrature Amplitude Phase Shift Keying.

 QCELP
Quadrature Code Excited Linear Prediction.

 QoS
Quality of Service; a broad term to describe the performance attributes of an end-to-end connection.

 QPSK
Quadrature Phase Shift Keying.

 RACE
Research in Advanced Communications in Europe.

 RACH
Random Access Channel; uplink only, allows the MS to request an SDCCH in response to a page or for a call.

 RAM
Random Access Memory.

 RFP
Radio Fixed Part; equivalent to a base station in a DECT system.

 RCC
Radio Common Carrier.

 RELP
Regular pulse Excitation Linear Prediction coding.

 Reuse
The assignment of frequencies or channels to cells so that adjoining cells do not use the same frequencies and cause interference whereas more distant cells can use the same frequencies. Reuse expands the capacity of a cellular network by enabling the use of the same channels throughout the network.

 RP
Radio Part.

 RNC
Radio Network Controller; the element which controls the Node Bs within a UMTS network. It is roughly analogous to a BSC in a GSM network.

 Roaming
A service unique to GSM which enables a subscriber to make and receive calls when outside the service area of his home network e.g. when travelling abroad.

 Router
A device which forwards information in a network on a connectionless basis.

 RRM
Radio Resource Management, part of the UMTS infrastructure.

 RT
Remote Terminal.

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 SACCH
Slow Associated Control Channel; transmits continuous measurements in parallel with operation of TCH or SDCCH; needed for handover decisions.

 SAR
Specific Absorption Rate.

 SB
Synchronisation Burst; used for time synchronisation of the mobile.

 S-CDMA
Synchronous CDMA (see CDMA).

 SCH
Synchronisation Channel; downlink only frame synchronisation and identification of base station.

 SCP
Switching/Service Control Point.

 SDCCH
Stand-alone Dedicated Control Channel; communications channel between the MS and the BTS. Used for signalling during call set-up before a TCH is allocated.

 SDLC
Synchronous Data Link Control.

 SDMA
Spatial Division Multiple Access.

 SGSN
Serving GPRS Support Node; the gateway between the RNC and the core network in a GPRS/UMTS network.

 SIM
Subscriber Identity Module; A smart card containing the telephone number of the subscriber, encoded network identification details, the PIN and other user data such as the phone book. A user’s SIM card can be moved from phone to phone as it contains all the key information required to activate the phone.

 SoHo
Small Office/Home Office.

 Streaming
An Internet derived expression for the one-way transmission of video and audio content.

 STK
SIM ToolKit: specified within the GSM standard, this allows operators to add additional functions to the phone menu in order to provide new services such as mobile banking or email.

 SMR
Specialised Mobile Radio; the US term for private mobile radio (See PMR).

 SMS
Short Message Service; a text message service which enables users to send short messages (160 characters) to other users. A very popular service, particularly amongst young people, with 400 billion SMS messages sent worldwide in 2002.

 SMSC
SMS Centre-the network entity which switches SMS traffic.

 SMSCB
SMS Cell Broadcast.

 SMS-MO
SMS Mobile Originated.

 SMS-MT
SMS Mobile Terminated.

 SMS-PP
SMS Point to Point.

 SP
Service Provider.

 SQAM
Staggered Quadrature Amplitude Modulation.

 SQPSK
Staggered Quadrature Phase Shift Keying.

 SS
Supplementary Service Support; handles special services.

 SS7
Signalling System Number 7 (See CCS7).

 SSP
Service Switching Point.

 STM
Synchronous Transfer Mode.

 Symbian
A company created by Psion, Nokia, Ericsson and Motorola in 1998 with the aim of developing and standardising an operating system which enable mobile phones from different manufacturers to exchange information.
The operating system is known as EPOC. Matsushita has subsequently joined Symbian.

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 TACS
Total Access Communications System (an AMPS variant deployed in a number of countries principally the UK).

 TAP
Transferred Account Procedure; the essential charging methodology for international GSM roaming. There have been four TAP standards, TAP1, TAP2, TAP2+ and TAP3. The latter offers variable record length and is sufficiently flexible to support all future requirements arising from the move to 3G.

 TBR
Technical Basis for Regulation (part of the ETSI standardisation process).

 TCH
Traffic Channel.

 TD-CDMA
Time Division CDMA.

 TD-SCDMA
Time Division-Synchronous CDMA; a CDMA variant developed by Chinese vendors which is claimed to offer high data rates and greater coverage.

 TDD
Time Division Duplex; a radio technology for use in unpaired spectrum. WCDMA/UMTS includes a band for TDD mode usage and both PHS and DECT use this technology.

 TDMA
Time Division Multiple Access; a technique for multiplexing multiple users onto a single channel on a single carrier by splitting the carrier into time slots and allocating these on a as-needed basis.

 Telematics
A wireless communications system designed for the collection and dissemination of information, particularly refers to vehicle-based electronic systems, vehicle tracking and positioning, on-line vehicle navigation and information systems and emergency assistance.

 TETRA
Terrestrial Trunked Radio; a European developed digital private mobile radio technology which is now being extensively deployed worldwide.

 Tetrapol
A competitive digital PMR technology to TETRA developed by French vendors.

 TFTS
Terrestrial Flight Telephone System.

 Timeslot
A frame within a TDMA schema; has a time interval of 576 microseconds. Physical content of a timeslot is known as a burst. Five different burst types exist, they are distinguished by different TDMA frame divisions (see NB, FB, SB, AB and DB).

 TIPHON
Telecommunications and Internet Protocol Harmonisation over Networks; an ETSI project designed to support the market for voice communications and voice band communications. In particular TIPHON will ensure that users on IP-based networks can communicate with those on circuit switched networks.

 TMN
Telecommunications Management Network.

 TMSI
Temporary Mobile Subscriber Identity; covers the IMSI to prevent over-the-air interception and tracing.

 TRAU
Transcoder Rate Adapter Unit; the transport unit for a 16kbit/s traffic channel on the A-bis interface.

 Tri-band
Refers to a mobile phone able to operate on the three internationally designated GSM frequencies- 900, 1800 and 1900MHz.

 TrueSync
A technology which enables the optimal synchronisation of calendars, address books, action lists and memoranda. It enables multi-point, one-step synchronisation of wireless and wireline devices, desktop computers and server-based applications and services.

 TRX
Transmitter/receiver (transceiver).

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 UI
User Interface.

 Um
The air interface between the BTS and the MS in a GSM network.

 Uu
The air interface between the Node B and the MS in a UMTS network.

 UMTS
Universal Mobile Telecommunications System; the European entrant for 3G; now subsumed into the IMT-2000 family as the WCDMA technology.

 UPN
Universal Personal Number.

 UPT
Universal Personal Telecommunications.

 URL
Uniform Resource Locator; the addressing system of the Internet.

 USO
Universal Service Obligation.

 UTRA
Universal Terrestrial Radio Access; the air interface component of WCDMA.

 UTRAN
Universal Terrestrial Radio Access Network; the UMTS radio access network comprising the RNC, Node B and the air interface.

 USIM
Universal Subscriber Identity Module; the 3G equivalent of the GSM SIM.

 UWB
Ultra Wide Band.

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 VAS
Value Added Services.

 VBR
Variable Bit Rate.

 VHE
Virtual Home Environment.

 VLR
Visitor Location Register.

 Vocoder
Voice coder.

 VoIP
Voice over Internet Protocol.

 VPN
Virtual Private Network.

 VSAT
Very Small Aperture Terminal.

 VSELP
Vector Sum Excited Linear Prediction.

 WAP
Wireless Application Protocol; a de facto standard for enabling mobile phones to access the Internet and advanced services. Users can access websites and pages which have been converted by the use of WML into stripped-down versions of the original more suitable for the limited display capabilities of mobile phones.

 WARC
World Administration Radio Conference; an ITU conference held at regular intervals to determine the allocation of spectrum for various services.

 WCDMA
Wideband CDMA; the technology created from a fusion of proposals to act as the European entrant for the ITU IMT-2000 family.

 WLL
Wireless Local Loop; a technique for providing telephony and low speed data services to fixed customers using wireless. Regarded as having considerably potential for rapidly addressing the telecommunications gap in developing countries. A number of different WLL solutions have been marketed based on cellular and cordless technologies.

 WLAN
Wireless Local Area Network; a short range radio network normally deployed in traffic hotspots such as airport lounges, hotels and restaurants. WLAN enables suitably equipped users to access the fixed network wirelessly, providing high speed access (up to 11Mbit/s download) to distant servers. The key WLAN technologies are the IEEE802.11 family and ETSI HIPERLAN/2.

 WML
Wireless Markup Language; a markup language developed specifically for wireless applications. WML is based on XML.

 WQAM
Weighted Quadrature Amplitude Modulation.

 WWW
World Wide Web.

XML
eXtended Markup Language.

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