wireless terms 3
IMEI
International Mobile Station Equipment Identity
Internet Mode
A wireless service launched in Japan in spring 1999 by NTT DoCoMo. The service is accessed by a wireless packet network (PDC-P) and the contents are described in a subset of the HTML language.
IMAP4
Internet Messaging Access Protocol
A remote mailbox access protocol. It enables efficient operation such as downloading only essential data by first acquisitioning the e-mail header prior to actual e-mail download. This feature makes the protocol well suited to remote environments.
Acronym | Description | Explanation |
I | In-Phase | For PSK modulation, the reference phase channel. See also Q. |
IF | Intermediate Frequency | The operating frequency in superheterodyne receivers where amplification, filtering and level control prior to demodulation is accomplished. |
IMSI | International Mobile Station Identity | |
IMT-2000 | International Mobile Telecommunication 2000 | A term used by the International Telecommunication Union, a United Nations agency, to describe the third generation mobile telephony due to be ready in 2000. Can also be applied to mobile telephone standards that meet a number of requirements in terms of transmission speed and other factors. |
IMTS | Improved Mobile Telephone Service | |
IN | Intelligent Network | Often referred to as the Advanced Intelligent Network, this is a network of equipment, software and protocols used to implement features on the network and support switching and control functions. |
Internet capability | Functionality in a wireless network enabling access to the Internet for web page viewing and e-mail purposes. | |
IP | Internet Protocol | A set of instructions defining how information is handled as it travels between systems across the Internet. |
IPR | Intellectual Property Rights | Also known as patents, these are the rights of an inventor or assignee to develop and commercialize an invention and license it, usually for a fee, to other manufacturers. |
IPv6 | Internet Protocol version 6. | The latest IP version. Address exhaustion is prevented by means of a long address field, thereby enabling further Internet expansion. In addition, security and mobility are built into the protocol. Currently utilized IP addresses are almost all IPv4, and with the present rate of Internet growth this type of address will be exhausted by 2010. IPv6 on the other hand enables 10 to the 29th power more available addresses than the previous IPv4. |
IS-136 | EIA Interim Standard 136 – NADC with Digital Control Channels | The North American digital mobile telephony standard based on TDMA technology. It is the version of the TDMA specification resulting in a fully digital 2nd generation system and is backward compatible with analog AMPS. See also TDMA and D-AMPS. |
IS-2000 | EIA Interim Standard 2000 (see cdma2000) | A standard for current CDMA systems providing a migration path to 3G services. |
IS-41 | Inter-network connection protocol for connecting systems based on both analog and digital US standards. | Inter-network connection protocol for connecting systems based on both analog and digital US standards. |
IS-54 | EIA Interim Standard for U.S. Digital Cellular | Original TDMA digital standard. Implemented in 1992. This standard was the first to permit the use digital channels in AMPS systems. It used digital traffic channels but retained the use of analog control channels. This standard was replaced by the IS-136 digital standard in 1996. |
IS-95a | EIA Interim Standard 95 (see cdmaOne) | The original digital mobile telephony standard based on CDMA technology. See also CDMA. |
1S-95b | Upgraded version of IS-95a that increases the maximum data rate to 115.2 kb/s. | |
ISDN | Integrated Services Digital Network. | A technology offering switched and fixed high speed transmission of voice, data and video through the existing telephone infrastructure. The service is based on 1 or more 64 kbps digital channels and does not use traditional modems. |
ISI | Inter-Symbol Interference | An interference effect where energy from prior symbols in a bit stream is present in later symbols. ISI is normally caused by filtering of the data streams. |
ITU | International Telecommunications Union | A United Nations agency that deals with telecommunications issues. |
IWF | Interworking Function | A technique for interfacing data between a wireless system and the telephone network. It usually involves the use of modems or data terminal adapters to convert the data transmitted over the air interface and mobile network to a format that can be recognized and carried by the public telecommunications network. |
jitter | Variation in the amount of time that it takes packets to traverse the network and arrive at a destination. | |
kHz | kiloHertz | A radio frequency measurement (one kilohertz = one thousand cycles per second). |
LAI | Location Area Identity | Information carried in the SIM of GSM handsets that identify the subscriber’s home area. This is used for billing and sub-net operation purposes. |
LAN | Local Area Network | A small data network covering a limited area, such as within a building or group of buildings. |
LAS-CDMA | Large Area Synchronized Code Division Multiple Access | A technology developed by LinkAir that offers higher spectral efficiency and moving speed for better mobile-application support.Also, its asymmetric traffic, higher throughput, and smaller delay provide improved IP support.Currently LAS-CDMA is being considered for phase 2 of the 1xEV standards.A LAS-CDMA TDD variant is compatible with systems such as TD-SCDMA. |
Lee’s model | A slope-intercept propagation prediction model developed at Bell Laboratories and popularized by William Lee. The model assumes an initial condition at a short distance from a base station and uses that as one end of a slope intercept model to predict path loss between a base station and a mobile unit. | |
line speed | Data transmission rate over a physical or wireless medium, typically given in number of bits per second. | |
link | The radio connection between a transmitter and a receiver. | |
link budget | A calculation involving the gain and loss factors associated with the antennas, transmitters, transmission lines and propagation environment used to determine the maximum distance at which a transmitter and receiver can successfully operate. | |
LMDS | Local Multipoint Distribution System | |
LNA | Low Noise Amplifier | |
location registration | One of several computer databases used to maintain location and other information on mobile subscribers. See HLR and VLR. | |
logical channel | A communications channel derived from a physical channel. A physical channel, i.e. RF channel, typically carries a data stream that contains several logical channels. These usually include multiple control and traffic channels. | |
LOS | loss of signal | |
LOS | line of sight | A description of an unobstructed radio path or link between the transmitting and receiving antennas of a communications system. |
LPA | linear power amplifier | The final amplification stage in a multicarrier transmitter that has been designed and optimized to produce a linear response. By operating in the linear mode, the amplifier reduces the non-linear effects that produce intermodulation products and side-lobe spectra that cause adjacent channel interference. |
LPC | Linear Predictive Coding | |
LSB | Least Significant Bit | In a binary coding scheme, the bit having the least numerical value. Analogous to the units position in a decimal number. |
lu | Standardized interface between a Radio Network Controller Network and Packet Subsystem (e.g. RNC-3GSGSN). | |
lub | Interface between a Base Station and Radio Network Controller. | |
lur | Open RNC-RNC interface. | |
MAC | Medium Access Control | |
macro cell | A large cell in a wireless system capable of covering a large physical area. Macrocells are used in rural areas and other areas where subscriber or traffic densities are low. | |
MAHO | Mobile Assisted Handoff | A handoff technique involving feedback from the mobile station as part of the handoff process. The feedback is usually in the form of signal level and quality measurements on the downlink and signal level measurements from neighbor cells. |
MAP | Mobile Application Part | |
MASHO | Mobile Assisted Soft Handoff | See MAHO. |
MC-CDMA | Multi-Carrier Code Division Multiple Access | Typically, this means the combination of three IS-95 carriers to form one wideband carrier. It is an evolution of IS-95 for third generation systems. Also called cdma2000. The current nomenclature is temporary, with a formal name for this technology to be determined under 3GPP2. |
Mcps | Mega Chips per Second | A measure of the number of bits (chips) per second in the spreading sequence of direct sequence spreading code. |
MHz | Megahertz | A unit of frequency equal to one million hertz or cycles per second. Wireless communications occur in the 800 MHz, 900 MHz and 1900 MHz bands. |
micro cell | A base station with a very small coverage area designed to provide service in areas having a very high density of mobile subscribers. Microcells are traditionally used in convention centers, airports and similar areas. | |
MIN | Mobile Identification Number | |
m-law companding | A type of non-linear (logarithmic) quantizing, companding and encoding technique for speech signals based on the m-law. This type of companding uses a m factor of 255 and is optimized to provide a good signal-to-quantizing noise ratio over a wide dynamic range. | |
MM | Mobility Management | Functions that track the location of a mobile station as it moves within a given area. |
MMM | Mobile Media Mode | The WWW:MMM logo is a marketing innovation comprising a unifying industry-wide marketing symbol representing leading edge web-based products and services. |
MMS | Multimedia Messaging Service | MMS is a new standard that is being defined for use in advanced wireless terminals. The service concept is derived from Short Message Service and allows for non-real-time transmission of various kinds of multimedia contents like images, audio, video clips, etc. As a further evolution of the current text mail, for example, electronic postcards, audio/video clips, etc. can be sent. |
mobile phone network | A network of cells. Each cell is served by a radio base station from where calls are forwarded to and received from your mobile phone by wireless radio signals. | |
MOS | Mean Opinion Score | |
MPE | multi-pulse excited | A multi-pulse process for determining the position and amplitude of sample pulses in a speech codec. |
MPEG | Moving Picture Experts Group | The group that has defined the standards for compressed video transmission. Can also refer to the file format itself. |
MPEG4 | Moving Picture Experts Group Compression Standard Version 4. | MPEG4 is a technology for compressing voice, video and related control data and is one of the MPEG (Moving Picture Experts Group) international standards. It is currently a focus of attention due to the fact that it enables high speed and stable video transmission even in heretofore difficult environments such as mobile communication. Incorporation of this leading edge technology will imbue 3G terminals with a rich multimedia capability. |
MS | Mobile Station | The term used to describe the customer terminal in a wireless network. |
MSA | Metropolitan Statistical Area | A geographic area over which a cellular operator is licensed to provide service. MSAs are groups of counties in metropolitan areas having common financial, commercial and economic ties and were first used to license cellular service in the early ’80s. MSAs cross state lines in some instances. MSAs were first used by the Dept. of Commerce to collect economic data. |
MSB | Most Significant Bit | In a binary coding scheme, the bit having the greatest numerical value. Analogous to the left-most numeric position in a decimal number. |
MSC | Mobile Switching Center | The location providing the mobile switching function in a second generation network wireless network. The MSC switches all calls between the mobile and the PSTN and other mobiles. |
MSK | Minimum Shift Keying | |
MTA | Major Trading Area | A geographic area over which a PCS operator is licensed to provide service. MTAs are a group of BTAs having common financial, commercial and economic ties and were first used to license PCS service in the middle ’90s. MTAs can be many times larger a cellular MSA and can cross multiple state lines in some instances. MTAs are used by the Rand-McNally corporation to summarize economic data. MTAs are one of the largest licensing areas used by the FCC. |
MTSO | Mobile Telephone Switching Office | The location providing the mobile switching function in a first generation wireless network. The MTSO switched all calls between the mobile and the PSTN and other mobiles. |
multiple access | The process of allowing multiple radio links or users to address the same radio channel on a coordinated basis. Typical multiple access technologies include FDMA, TDMA, CDMA, and FHMA. | |
NADC | North American Digital Cellular | |
NAM | Number Assignment Module | The programmable module in an AMPS analog phone used to contain the MIN, ESN, home system ID and other information. |
N-AMPS | Narrowband Advanced Mobile Phone System | Combines the AMPS transmission standard with digital signaling information to effectively triple the capacity of AMPS while adding basic messaging functionality. |
NM | Network Management | |
NMC | Network Management Center | An operations center used to manage network resources such as the MSC, location registers and base stations. |
NML | Network Management Layer | |
NMT | Nordic Mobile Telephony | The common Nordic standard for analog mobile telephony as established by the telecommunications administrations in Sweden, Norway, Finland and Denmark in the early 1980s. NMT systems have also been installed in some European countries, including parts of Russia, and in the Middle East and Asia. NMT is operated in 450 MHz and 900 MHz bands. |
NMT-450 | Nordic Mobile Telephony – 450 | An early cellular system developed and operated in northern Europe utilizing the 450 MHz band. |
node | A point of connection in a network. A node is often a device on the network that can process a transmission or forward it to anogther node. | |
Node B | 3G UMTS base station transceiver. Node B (also called the base station controller or radio base station) provides the gateway between the handset/RF interface and the radio network controller via the Iub interface. | |
noise figure | A figure of merit for receivers and preamplifiers representing the amount of excess noise added to the signal by the amplifier or receiving system itself. The lower the noise figure, the less excess noise is added to the signal. | |
NRZ | Non Return to Zero | |
NSS | Network Switching Subsystem | |
Nyquist rate | The minimum sampling rate proposed by Nyquist for converting a band limited waveform to digital pulses. The rate must be at least twice the highest frequency of interest in the waveform being sampled. | |
OAM&P | Operations, Administration, Maintenance & Provisioning Center | An operations center used to operate, administer, maintain and provision the network. |
OCQPSK | Orthogonal Complex Quadrature Phase Shift Keying | |
OFDM | Orthogonal Frequency Division Multiplex | |
OMC | Operations & Maintenance Center | A location used to operate and maintain a wireless network. |
OQPSK | Offset Quadrature Phase Shift Keying | A type of QPSK modulation that offsets the bit streams on the I and Q channels by a half bit. This reduces amplitude fluctuations and helps improve spectral efficiency. |
ORFS | Output Radio Frequency Spectrum | A measurement for GSM signals that tests for interference in the adjacent frequency channels (ARFCNs) and results from two effects: modulation within the bursts and the power that ramps up and down, or switching transients. ORFS is a critical GSM transmitter measurement. |
OSI | Open System Interconnect | |
OVSF | Orthogonal Variable Spreading Function | |
PA | Power Amplifier | A device for taking a low or intermediate-level signal and significantly boosting its power level. A power amplifier is usually the final stage of amplification in a transmitter. |
PABX | Private Automatic Branch Exchange | A customer premise telephone switching system capable of interfacing to a telephone central office with trunk groups and routing calls based on a 3 or 4 digit telephone extension number. |
packet | A piece of data transmitted over a packet-switching network such as the Internet. A packet includes not just data but also address information about its origination and destination. | |
packet radio | A radio system that operates by sending data in packets. | |
PACS | Personal Access Communications System | |
PAD | Packet Assembler/Disassembler | The part of a packet transmission system that segments the transmit data into packets and returns the receive data to longer messages. [5] |
pad | See attenuator. | |
PAM | pulse amplitude modulation | A technique for encoding the samples of an analog waveform as part of the PCM process. Also used to display the amplitude of QAM signals in an eye diagram. |
path loss | The amount of loss introduced by the propagation environment between a transmitter and receiver. | |
PBX | Private Branch Exchange | An exchange system used in companies and organizations to handle internal and external calls. |
PCH | Paging Channel | |
PCIA | Personal Communications Industry Association | A leading international trade association representing the personal communications services (PCS) industry. Its primary objective is to advance regulatory policies, legislation, and technical standards in this industry. |
PCM | Pulse Code Modulation | |
PCN | Personal Communications Network | A standard for digital mobile phone transmissions operating at a frequency of 1800 MHz (also referred to as GSM 1800). It is used in Europe and Asia Pacific. |
PCS | Personal Communications Services | Generally, a marketing term used to describe a wide variety of two-way digital wireless service offerings in North America operating at 1900 MHz. PCS services include next generation wireless phone and communication services, wireless local loop, inexpensive walk-around communications service with lightweight, low-powered handsets, in-building cordless voice services for business, in-building wireless LAN service for business, enhanced paging service as well as wireless services integrated with wired networks. A Personal Communications System refers to the hardware and software that provide communications services. |
PCS | Personal Communications System | The infrastructure used to provide personal communications services. |
PCU | Packet Control Unit | A device that must be added to older GSM base stations if they are to carry GPRS traffic. Functions include converting packet data into a format that can be transferred over the air interface, managing radio resources,and implementing quality of service (QoS) measurements. |
PDA | Personal Data Appliance/Assistant | Also known as Personal Digital Appliance. |
PDC | Personal or Pacific Digital Cellular | A Japanese standard for digital mobile telephony in the 800 MHz and 1500 MHz bands. To avoid the previous problem of lack of compatibility between the differing types of earlier analog mobile phones in Japan (i.e. NTT type and US developed TACS type), digital mobile phones have been standardized under PDC. In the case of the PDC standard, primarily six channel TDMA (Time Division Multiple Access) technology is applied. PDC, however, is a standard unique to Japan which renders such phone units incompatible with devices which adopt the more worldwide prevalent GSM standard. Nevertheless, digitalization under the standard enables ever smaller and lighter mobile phones which in turn has spurred market expansion. As a result, over 93% of all mobile phones in Japan are now digital. |
Probability Density Function | ||
PHP | Personal Handy Phone | The mobile hand-set used with the Japanese Personal Handy Phone system. |
PHS | Personal Handy Phone System | |
physical channel | The actual radio channel that carries the various logical and traffic channels in a wireless system. | |
pico cell | Very small cell in a mobile network for boosting capacity within buildings. | |
pilot pollution | A type of co-channel interference in CDMA systems caused when the pilot code from a distant cell or base station is powerful enough to create an interference problem. | |
PIN | Personal Identification Number | A code used for all GSM-based phones to establish authorization for access to certain functions or information. The PIN code is delivered together with your subscription. |
PLL | Phase Locked Loop | PLL is a major component in the frequency synthesizer scheme. This device provides a wide, flexible range of internal frequency dividers which allow the designer the ability to create a synthesizer to match design requirements. |
PLMN | Public Land-Mobile Network | A European term used to describe the GSM system. |
PMR | Private Mobile Radio | Generally for use within a defined user group such as the emergency services or by the employees of a mining project. |
PN | Pseudo-Noise | Historically, the Ministry of Post, Telecommunications and Telegraph. Now a term to describe the incumbent, dominant operator in a country, many of which are being or have been privatized. |
PNCQPSK | Pseudo-Noise Complex Quadrature Phase Shift Keying | The spreading technique that uses basic complex scrambling and PN signals for Is and Qs. For more information see Agilent application note “HPSK Spreading for 3G”. |
point to point | A direct link between two network nodes. | |
POCSAG | Post Office Code Special Advisory Group | |
power control | A technique for managing the transmit power in base stations and mobiles to a minimum level needed for proper performance. Downlink power control applies to base stations and uplink power control to mobiles. Power control is used in nearly all wireless systems to manage interference, and in the case of mobiles, to extend battery life. | |
power spectral density | Power normalized to 1 Hz. Knowing the power spectral density and system bandwidth, the total power can be calculated. | |
PQA | Palm Query Applications | |
PRBS | Pseudo-Random Binary Sequence | |
PRMA | Packet Reservation Multiple Access | |
PSD | Power Spectral Density | See power spectral density. |
PSK | Phase Shift Keying | A broad classification of modulation techniques where the information to be transmitted is contained in the phase of the carrier wave. |
PSTN | Public Switched Telephone Network | Standard domestic and commercial phone service. |
Q | Quadrature-Phase | The quadrature phase channel in a phase shift keyed system having more that 2 phase states. |
QAM | Quadrature Amplitude Modulation | Ã? |
QCIF | Quarter CIF (1/4 CIF). A video image format which employs 176 horizontal pixels and 144 vertical lines. | Although resolution is courser than CIF, QCIF consumes less memory while still achieving an acceptable level of clarity on small displays such as those incorporated in mobile phones. |
QoS | quality of service | A measure of the quality of the signal transmitted over the RF channel. In some systems, the QoS measurement is used to dynamically adjust operational parameters such as transmitter power levels and coding rates. |
QPSK | Quadrature Phase Shift Keying | Ã? |
RAB | Radio Access Bearer | |
RACE | Research in Advanced Communications Equipment | |
RACH | Random Access Channel | The channel used by mobiles in GSM and W-CDMA systems to attempt to gain access to the system when first attaching to it. |
radio port | The T1P1 PCS architecture model equivalent to the BTS. | |
RAN | Radio Access Network | |
random access | A technique for radio access to a network where an access message is not coordinated or administered by the network and can collide with other attempts by others to access the network over the same channel. | |
Rayleigh fading | A type of signal fading caused by independent multipath signals having a Rayleigh PDF. | |
RC | Radio Configuration | RC defines the physical channel configuration of cdma2000 (IS-2000) signals. Each RC specifies a set of data rates based on either 9.6 or 14.4 kbps. RC1 is the backwards-compatible mode of cdmaOne for 9.6 kbps voice traffic. It includes 9.6, 4.8, 2.4, 1.2 kbps data rates and operates at Spread Rate 1 (SR1). RC3 is a cdma2000 specific configuration based on 9.6 kbps that also supports 4.8, 2.7, and 1.5 kbps for voice, while supporting data at 19.2, 38.4, 76.8, and 153.6 kbps. RC3 also operates at SR1. For more information see Agilent application note “Performing cdma2000 Measurements Today”. |
REAG | Region | A geographic area over which a WCS operator is licensed to provide service. REAGs are a group of economic areas (EAs) and were first used to license WCS service in the late ’90s. REAGs are very large, with 6 REAGs covering the entire continental United States. |
receive diversity | The process of providing two independent receiving systems and spatially separated antennas to overcome fading effects on the radio signal. | |
registration | This is the process by which a mobile station informs the immediate service provider of its presence in the network and its desire to receive service. | |
Repeater | Receives radio signals from the base station. They are then amplified and re-transmitted to areas where radio shadow occurs. Repeaters also work in the opposite direction, i.e. receiving radio signals from mobile telephones, then amplifying and re-transmitting them to the base station. | |
reuse factor | Also known as frequency reuse factor, is the number of distinct frequency sets used per cluster of cells. | |
RF | radio frequency | Electromagnetic waves in the frequency range of 30 kHz to 300 GHz. [2] |
RNC | Radio Network Controller under the UMTS system. | A complex network element of the RAN that connects to and co-ordinates as many as 150 base stations in W-CDMA systems. It is involved in managing activities such as hand-over of active calls between base stations. |
Roaming | Within your home network, this means that your mobile phone automatically sets up communication procedures with different radio base stations when on the move. International roaming means that you can use networks other than your own when traveling abroad. | |
Router | A data switch that handles connections between different networks. A router identifies the addresses on data passing through the switch, determines which route the transmission should take and collects data in so-called packets which are then sent to their destinations. | |
Routing | The forwarding of data packets in packet-switched networks, to the intended address. | |
RPE-LTP | Regular Pulse Excited-Long Term Prediction | A type of speech coding using regularly spaced pulses in an excitation frame and a long term predictor to model the fine structure (pitch). |
RSA | Rural Service Area | A geographic area over which a cellular operator is licensed to provide service. RSAs are a group of rural counties having common financial, commercial and economic ties and were used to license cellular service Rural areas in the latter ’80s. RSAs cross state lines in some instances and were developed during a public rule making process at the FCC in 1987 and 1988.. |
RSSI | Received Signal Strength Indication | |
S/I | signal-to-interference ratio | |
S/N | signal-to-noise ratio | |
SACCH | Slow Associated Control Channel | |
sampling | The first process performed in the conversion of analog waveforms to a digital format. It converts a continuous- time signal into a discrete-time signal or sequence of numbers. | |
SAT | Set-up Audio Tone | An audio tone in the 6 kHz range added to the downlink or forward channel in analog cellular systems. The mobile detects and returns the tone. The SAT tone is used to determine channel continuity, and only one SAT tone is usually assigned to a base station or sector. |
SCCH | Signaling Control Channel | |
SCH | Synchronization Channel | A logical channel used by mobile stations to achieve time synchronization with the network. Used in GSM, cdma2000, and W-CDMA systems. [1] |
SDCCH | Slow Dedicated Control Channel | |
SDH | Synchronous Digital Hierarchy | An international standard for synchronous optical transmission. This standard allows the world-wide connection of digital networks. |
SDMA | Space Division Multiple Access | Also known as multiple beam frequency reuse, this technique employs spot beam antennas to reuse frequencies by pointing the antenna beams using the same frequency in different directions. |
SFHMA | Slow Frequency Hopped Multiple Access | |
shadow fading | A phenomenon that occurs when a mobile moves behind an obstruction and experiences a significant reduction in signal power. | |
SHF | Super High Frequency | |
Signal Booster | Compensates for loss of effect (weakening of the signal in the co-axial cable) between the outer antenna and the phone. Applies to both incoming and outgoing signals. | |
SIM Card | Subscriber Identity Module Card | |
slow fading | A long term fading effect changing the mean value of the received signal. Slow fading is usually associated with moving away from the transmitter and experiencing the expected reduction in signal strength. | |
SMR | Specialized Mobile Radio | |
SMS | Short Messaging Service (Service Management System) | |
SNR | Signal-to-Noise Ratio | |
spread spectrum | A term used to describe a system that uses spectrum spreading techniques in its operation. | |
SR | Spread Rate | Spread rate is also known as the chip rate and is the rate of the digital code used to spread the information. The spreading rate is typically at least 100x the information rate. |
SS | Spread Spectrum | See spread spectrum. |
SS7 | Signal System 7 | |
SSD | Shared Secret Data | |
STD | Selective Transmit Diversity | |
supplementary services | A group of network layer protocol functions that provide call independent functions for mobile phones. These include: call forwarding, follow-me, advice of charge, reverse charging, etc. | |
Symbian | Owned by Ericsson, Nokia, Motorola, Panasonic and Psion, Symbian creates an advanced, open, standard operating system – Symbian OS – for its licensees. Symbian OS is designed for next-generation mobile phones and enables a broad, international, developer community. Phones using Symbian OS include the Ericsson R380 and Nokia 9210. | |
symmetric | In communications networks, providing the same data rate in each direction. | |
TAMS | Temporary Mobile Station Identity | |
TCH | Traffic Channel | A logical channel that allows the transmission of speech or data. In most second generation systems, the traffic channel can be either full or half-rate. |
TCH/F | Traffic Channel – full rate | |
TCH/H | Traffic Channel – half rate | A traffic channel using half rate voice coding. |
TCM | Trellis Code Modulation | A type of channel coding that, unlike block and convolutional codes, provide coding gain by increasing the size of the signal alphabet and use multi-level phase signalling. |
TCP | Transmission Control Protocol | TCP/IP is the standard communications protocol required for computers communicating over the Internet. To communicate using TCP/IP, computers need a set of software instructions or components called a TCP/IP stack. |
TDD | Time Division Duplex | A duplexing technique dividing a radio channel in time to allow downlink operation during part of the frame period and uplink operation in the remainder of the frame period. See also duplex. |
TDMA | Time Division Multiple Access | A technology for digital transmission of radio signals between, for example, a mobile telephone and a radio base station. In TDMA, the frequency band is split into a number of channels which in turn are stacked into short time units so that several calls can share a single channel without interfering with one another. Networks using TDMA assign 6 timeslots for each frequency channel. TDMA is also the name of a digital technology based on the IS-136 standard. TDMA is the current designation for what was formerly known as D-AMPS. See also IS-136 and D-AMPS. |
TDN | Temporary Directory Number | |
TD-SCDMA | Time Division Synchronous Code Division Multiple Access | A new technology developed by Siemens and the China Academy of Telecommunication Technology. TD-SCDMA is part of the ITU 3G standard harmonization and will likely be adopted by some operators in China. This proposed standard is 1.6 MHz wide and uses multiple timeslots, synchronous CDMA, and new detection and interference cancellation schemes. |
TDTD | Time Division Transmit Diversity | |
terminal | In wireles communications, used synonymously with such terms as mobile handset, mobile station, user equipment, or mobile device. | |
TIA | Telecommunications Industry Association (U.S.) | |
time dispersion | Time dispersion is a manifestation of multipath propagation that stretches the signal in time so that the duration of the received signal is greater than the transmitted signal. | |
TOA | Time of Arrival | A location technique that uses GSM timing to triangulate the position of a handset relative to active base stations. Accuracy is good indoors and in areas of dense base-station coverage, and TOA can be used with legacy handsets. Specialized equipment is needed at the base station, however, and planning, deployment, and maintenance costs can be high. |
transceiver | A transmitter and receiver contained in one package. A 2-way radio or cell phone is an example of a transceiver. | |
transmission plane | In a wireless communications network, the transmission plane consists of layered protocols that transfer user information and provide control procedures such as flow control and error correction. | |
transmit diversity | A technique utilizing multiple transmit stations to originate the downlink signal and improve performance. The station used is determined by either a fixed pattern or a quality measurement at the mobile. See also TDTD, STD and TSTD. | |
TSTD | Time Switched Transmit Diversity | |
TTA | Telecommunications Technology Association (Korea) | A telecommunications standards setting body in Korea. |
TTC | Telecommunications Technology Committee (Japan) | A private-sector corporate body established in 1985 to prepare domestic standards relevant to Japanese telecommunications. |
tunneling | Sending data intended for a private network through the public network using a temporary, secure path. Tunneling enables virtual private networks to send data across the Internet, for example. Several protocols exist for tunneling, including the point-to-point protocol (PTPP) developed by Microsoft and others, and the generic routing encapsulation (GRE) protocol developed by Cisco Systems. | |
UDP | User Datagram Protocol | An alternative to TCP used widely in streaming audio and video applications. UDP does not insist on retransmission of dropped packets, thus it uses bandwidth more efficiently in applications with less need for error detection and correction. |
UE | User Equipment | In a 3G UMTS network, User Equipment (also called the mobile station or handset) includes mobile cellular telephones, handheld personal digital assistants (PDAs), and cellular modems connected to PCs. |
UHF | Ultra High Frequency | The RF spectrum between 300 MHz and 3 GHz. |
UL | Uplink | See uplink. |
UMTS | Universal Mobile Telecommunications System | Third generation telecommunications system based on W-CDMA DS. |
UNIX | A computer operating system. UNIX is designed to be used by many people at the same time and has TCP/IP built-in. It is a very common operating system for servers on the Internet. | |
uplink | The transmission path from the mobile station up to the base station. | |
UPT | Universal Personal Telecommunications | |
USIM | Universal Subscriber Identity Module | This upgrade to the SIM card enables use with IMT-2000. |
UTRA | UMTS Terrestrial Radio Access | |
UTRAN | UMTS Terrestrial Radio Access Network | The radio access network based on the UTRA standard. |
UUT | Unit Under Test | An acronym describing some type of electrical apparatus connected to test instrumentation. The apparatus can range from a simple circuit a complex subsystem such as a mobile phone, base station or MSC. See also DUT. |
UWC | Universal Wireless Consortium | Body of vendors and operators promoting and implementing the IS-136 digital standard. Also specifying the future development of the standard and facilitating roaming agreements between IS-136 operators. |
VAD | voice activity detector | The device that detects voice activity and allows DTX to operate. VAD, in conjunction with DTX reduces power consumption in the mobile station and RF interference in the system by muting the transmitter when there is no voice to transmit. |
VHF | Very High Frequency | |
VLR | Visitor Location Register | |
VOIP | Voice Over Internet Protocol | A technology for transmitting ordinary telephone calls over the Internet using packet-linked routes. VoIP is not simply for voice over IP, but is designed to accommodate two-way video conferencing and application sharing as well. |
VPN | Virtual Private Network | |
VSELP | Vector Sum Excited Linear Predictive | A type of speech coding using an excitation signal generated from three components: the output of a long term or pitch filter and two codebooks. VSELP was used in the IS-54 standard and operated at a rate of 8 kbps. |
W3C | World Wide Web Consortium | A sector-wide body which promotes standardization of WWW technology. Major Internet related vendors are consortium members, and to date the body has standardized a range of crucial technologies including HTTP, HTML, |
Walsh Code | A group of spreading codes having good autocorrelation properties and poor crosscorrelation properties. Walsh codes are the backbone of CDMA systems and are used to develop the individual channels in CDMA. For IS-95, here are 64 codes available. Code 0 is used as the pilot and code 32 is used for synchronization. Codes 1 though 7 are used for control channels, and the remaining codes are available for traffic channels. Codes 2 through 7 are also available for traffic channels if they are not needed. For cdma2000, there exists a multitude of Walsh codes that vary in length to accommodate the different data rates and Spreading Factors of the different Radio Configurations. For more information see Agilent application note “Performing cdma2000 Measurements Today”. | |
WAN | Wide Area Network | A network of computers and interconnected LANs, typically spread out over a large area. |
WAP | Wireless Application Protocol | A free, unlicensed protocol for wireless communications that makes it possible to create advanced telecommunications services and to access Internet pages from a mobile telephone. WAP is a de facto standard that is supported by a large number of suppliers. See also http://www.wapforum.org |
WCA | Wireless Communications Association | The Wireless Communications Association represents the fixed broadband wireless access industry worldwide. It’s mission is to advance the interests of the wireless systems that provide data (including Internet and e-commerce), voice and video services on a subscription basis through land-based towers to fixed reception/transmit devices. |
WCDMA | Wideband Code Division Multiple Access | See W-CDMA. |
W-CDMA | Wideband-Code Division Multiple Access | |
WDM | Wavelength Division Multiplexing | A new technology that uses optical signals on different wavelengths to increase the capacity of fiber optic networks in order to handle a number of services simultaneously. |
WLAN | Wireless Local Area Network | A wireless version of the LAN. Provides access to the LAN even when the user is not in the office. |
WLL | Wireless Local Loop | A wireless connection of a telephone in a home or office to a fixed telephone network. |
WML | Wireless Markup Language | A markup language developed specifically for wireless applications. WML is based on |
WOS | Wireless Office Systems | A technology that allows the user to transfer calls to a mobile telephone. |
WPABX | Wireless Private Automatic Branch Exchange | A customer premise telephone switching system using wireless technology to link the individual user stations to the central switching unit. The WPABX is capable of interfacing to a telephone central office with trunk groups and routing calls based on a 3 or 4 digit telephone extension number. |