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There are 63 names in this directory beginning with the letter A.
A-Band cellular

In the U.S. cellular service industry, A-Band cellular is the alternative carrier to the regional Bell operating company's cellular subsidiary

A-Key

A-key is a secret number issued to a cellular phone that is used in conjunction with a subscriber's shared secret data information for authentication

A-MIMO: Adaptive Multiple Input Multiple

Adaptive Multiple Input Multiple Output (A-MIMO or Adaptive MIMO) is a scheme to enhance the MIMO technology by employing adaptive coding and modulation techniques for the purpose of improving channel capacity, diversity, and robustness of wireless communications. In an adaptive MIMO system, the system parameters are jointly optimized to adapt to the changing channel conditions through link adaptation techniques that can track the time-varying characteristics of the wireless channel. The goal is to maximize the resources available in multiple antenna channels by using optimal schemes at all times.

A2DP: Advanced Audio Distribution Profil

The Advanced Audio Distribution Profile (A2DP) in Bluetooth specifies the protocols and procedures that define the distribution of high quality audio content, in either mono or stereo on Asynchronous Connectionless Link (ACL) channels.

AAS: Adaptive Antenna System

Adaptive Antenna System (AAS), also called Advanced Antenna System, is a technology to enable the network operators to increase the wireless network capacity. In addition, adaptive antenna systems offer the potential of increased spectrum efficiency, extended range of coverage and higher rate of frequency reuse. Adaptive antenna systems consist of multiple antenna elements at the transmitting and/or receiving side of the communication link, whose signals are processed adaptively in order to exploit the spatial dimension of the mobile radio channel. Depending on whether the processing is performed at the transmitter, receiver, or both ends of the communication link, the adaptive antenna technique is defined as multiple-input single-output (MISO), single-input multiple-output (SIMO), or multiple-input multiple-output (MIMO).

Absolute Grant

Absolute Grant (AG), a term used in the mobile wireless channel definition, means the absolute value of the power offset permitted for the power usage.

Absorption Spectrum

Absorption Spectrum is a diagram which shows the wavelengths of electromagnetic radiation absorbed by a material. The material could be a gas, a solute or a solid. An absorption spectrum is, in a sense, the inverse of an emission spectrum.

AC: Authentication Center (or AUC)

The Authentication Centre (AC or AUC) is a function to authenticate each SIM card that attempts to connect to the GSM core network (typically when the phone is powered on). Once the authentication is successful, the HLR is allowed to manage the SIM and services described above. An encryption key is also generated that is subsequently used to encrypt all wireless communications (voice, SMS, etc.) between the mobile phone and the GSM core network.

ACCH: Associated Control Channel

Associated Control Channel(ACCH) is the GSM signalling channels associated with a user’s traffic channel or dedicated signalling channel. Two ACCH are defined for GSM Circuit Switched operation. These are SACCH (Slow Associated Control Channel) and FACCH (Fast Associated Control Channel). In GPRS packet operation, an ACCH is allocated in conjunction with a PDTCH (Packet Data Traffic Channel) and is termed as PACCH (Packet Associated Control Channel).

ACELP: Algebraic Code Excited Linear Pre

Algebraic Code Excited Linear Predictive (ACELP) is an algebraic technique used to populate codebooks for CELP speech coders. This technique results in more efficient codebook search algorithms.

ACIR: Adjacent Channel Interference Rati

Adjacent Channel Interference Ratio (ACIR) is the ratio of wanted power to the interference power from the adjacent channels.

ACLR: Adjacent Channel Leakage Ratio

Adjacent Channel Leakage Ratio (ACLR) is a measure of transmitter performance for WCDMA. It is defined as the ratio of the transmitted power to the power measured after a receiver filter in the adjacent RF channel. This is what was formerly called Adjacent Channel Power Ratio. ACLR is specified in the 3GPP WCDMA standard.

ACPR: Adjacent Channel Power Ratio

Adjacent Channel Power Ratio (ACPR) is a measurement of the amount of interference, or power, in the adjacent frequency channel. ACPR is usually defined as the ratio of the average power in the adjacent frequency channel (or offset) to the average power in the transmitted frequency channel. It is a critical measurement for CDMA transmitters and their components. It describes the amount of distortion generated due to nonlinearities in RF components. The ACPR measurement is not part of the cdmaOne standard.

ACS: Adjacent Channel Selectivity

Adjacent Channel Selectivity (ACS) is a measurement of a receiver's ability to process a desired signal while rejecting a strong signal in an adjacent frequency channel. ACS is defined as the ratio of the receiver filter attenuation on the assigned channel frequency to the receiver filter attenuation on the adjacent channel frequency.

ACTS: Advanced Communications Technology

Advanced Communications Technology and Services (ACTS) is an organization in Europe spearheading the development of 3G technologies in Europe. ACTS succeeded RACE and is focusing on wideband multiple access techniques.

Ad hoc

Ad hoc, also known as Ad hoc mode, refers to a short-term wireless network framework created between two or more wireless network adapters without going through an access point. In other words, an Ad hoc network allows computers to “talk” (send data) directly to and from one another. Ad hoc networks are handy for quickly trading files when you have no other way of connecting two or more computers. For an ad hoc network to work, each computer on the network needs a wireless network card installed, and you must set your wireless network cards (installed in each computer on the network) to Ad Hoc mode.

Ad hoc mode

Ad hoc mode refers to a wireless network in which devices can communicate directly with one another without using an AP or a connection to a regular network.

Ad hoc network

Ad hoc network refers to a short-term wireless network framework created between two or more wireless network adapters without going through an access point. Ad hoc networks are handy for quickly trading files when you have no other way of connecting two or more computers.

Adaptive array antennas

Adaptive array antenna is a type of advanced smart antenna technology that continually monitors a received signal and dynamically adapts signal patterns to optimize wireless system performance. The arrays use signal processing algorithms to adapt to user movement, changes in the radio-frequency environment and multi-path and co-channel interference.

Adaptive Equalizer

Adaptive Equalizer is a channel equalizer whose parameters are updated automatically and adaptively during the transmission of data. These equalizers are commonly used in fading channels to improve transmission performance.

Adaptive power control

Adaptive power control is a technique employed by wireless infrastructure systems that lowers the power of a signal in a cell site whenever the site detects that the user's phone is close to the source of the signal. This saves power in the phone, and thus saving battery life too.

ADC: Analog-to-Digital Converter

Analog-to-Digital Converter (ADC, A/D or A to D) is an electronic device that converts continuous signals to discrete digital numbers. The reverse operation is performed by a digital-to-analog converter (DAC). ADC can uniquely represents all analog input values within a specified total input range by a limited number of digital output codes.

Adjacent Channel

Adjacent Channel is a channel or frequency that is directly above or below a specific channel or frequency. First-adjacent is immediately next to another channel, and second-adjacent is two channels away, and so forth. Information on adjacent channels is used in keeping stations from interfering with one another.

Adjacent channel interference

Adjacent channel interference refers to signal impairment to one frequency due to presence of another signal on a nearby frequency.

ADPCM: Adaptive Differential Pulse Code

Adaptive Differential Pulse Code Modulation(ADPCM) is the process by which analog voice samples are encoded into high-quality digital signals. The first ADPCM standardized by the CCITT is G.721 for 32 kbps. Later came the standards G.726 and G.727 for 40, 32, 24 and 16 kbps. ADPCM is used to send sound on fiber-optic long-distance lines as well as to store sound along with text, images, and code on a CD-ROM.

AGC: Automatic Gain Control

Automatic Gain Control (AGC) is a system which holds the gain and, accordingly, the output of a receiver substantially constant in spite of input-signal amplitude fluctuations.

AGCH: Access Grant Channel

Access Grant Channel(AGCH) is a downlink control channel used in GSM systems to assign mobiles to a Stand-alone Dedicated Control Channel (SDCCH) for initial assignment.

AGPS: Assisted Global Positioning System

Assisted Global Positioning System (AGPS) is a method used for determining mobile station (MS) location in terms of universal latitude and longitude coordinates. This capability has been mandated for wireless carriers in the United States by the Federal Communication Commission, so emergency callers can be easily located in times of crisis. AGPS implies that the mobile not only has GPS hardware and software but that the wireless network is providing the mobile with short assistance messages.

AIN: advanced intelligent network

Advanced Intelligent Network (AIN) was Introduced by AT&T Network Systems in 1991 to enable service providers to define, test and introduce new multimedia messaging, PCS and cell routing.

Air Interface

In wireless communications, the air interface is the radio frequency (RF) part of the network that transmits signals between base stations and end-user equipment. The air interface is defined by specifications for a specific format such as GSM, cdma2000, GPRS, or W-CDMA.

AirPort

AirPort is the Apple's marketing name for its 802.11b wireless networking technology. AirPort, based on IEEE 802.11b, is a local area wireless networking system from Apple Computer and certified as compatible with other 802.11b devices. A later family of products based on the IEEE 802.11g specification is known as AirPort Extreme, offering speeds of up to 54 megabits per second and interoperability with older products.

Airtime

Airtime is the time elapsed between the start of a call achieved by connecting to your service provider's network and the termination of a call achieved by pressing the end button. Network connection time includes signals received prior to voice transmission, such as busy signals and ringing.

Aliasing

Aliasing is a type of signal distortion that occurs when sampling frequency of a signal is less than the Nyquist rate.

ALOHA

ALOHA is a packet-based radio access protocol developed by the University of Hawaii where every packet sent is acknowledged. Lack of an acknowledgement is an indication of a collision and results in a retransmission.

AM: Amplitude Modulation

Amplitude Modulation (AM) uses amplitude variation in proportion to the amplitude of the modulating signal, and is usually taken as DSB-LC for commercial broadcast transmissions and DSB-SC for multiplexed systems.

AMC: Adaptive Modulation and Coding

Adaptive Modulation and Coding (AMC) is an alternative link adaptation method in 3G mobile wireless communication. AMC provides the flexibility to match the modulation-coding scheme to the average channel conditions for each user. With AMC, the power of the transmitted signal is held constant over a frame interval, and the modulation and coding format is changed to match the current received signal quality or channel conditions.

Amplifier

Amplifier, or electronic amplifier, is commonly used in radio and television transmitters and receivers, high-fidelity (“hi-fi”) stereo equipment, microcomputers and other electronic digital equipment, and guitar and other instrument amplifiers.

AMPS: Advanced Mobile Phone System ervic

Advanced Mobile Phone System (AMPS) Service is the analog mobile phone system standard, introduced in the Americas during the early 1980s. Though analog is no longer considered advanced at all, the relatively seamless cellular switching technology AMPS introduced was what made the original mobile radiotelephone practical, and was considered quite advanced at the time.

AMR: Advanced Multi Rate Codec

Advanced Multi Rate Codec (AMR) is a speech codec standardized by ETSI for GSM. The codec adapts its bit-rate allocation between speech and channel coding, thereby optimizing speech quality in various radio channel conditions. For this reason, 3GPP (under which the next stage GSM speech quality will be realized) has selected the AMR codec as an essential speech codec for the next generation system.

AMS: Adaptive MIMO Switching

Adaptive MIMO Switching (AMS) is a scheme to switch between multiple MIMO modes to maximize spectral efficiency with no reduction in coverage area. In an adaptive MIMO switching system, the system parameters are jointly optimized to adapt to the changing channel conditions through link adaptation techniques that can track the time-varying characteristics of the wireless channel. The goal is to maximize the resources available in multiple antenna channels by using optimal schemes at all times.

AMTA: American Mobile Telecommunications

American Mobile Telecommunications Association (AMTA) is a trade group, based in Washington, D.C., representing specialized mobile radio operators

Analog System

Analog system uses an analog transmission method to send voice, video and data-using analog signals, such as electricity or sound waves, that are continuously variable rather than discreet units as in digital transmissions. Mobile analog systems include AMPS, NMT and ETACS.

Analog Transmission

Analog Transmission refers to signals propagated through the medium as continuously varying electromagnetic waves.

Angle diversity

Angle diversity is a technique using multiple antenna beams to receive multipath signals arriving at different angles.

Antenna

Antenna is a device which radiates and/or receives radio signals.

Antenna beamwidth

Antenna beamwidth, also known as the half-power beamwidth, is the angle of an antenna pattern or beam over which the relative power is at or above 50% of the peak power.

Antenna directivity

Antenna directivity, also known as antenna gain, is the relative gain of the main beam of an antenna pattern to a reference antenna, usually an isotropic or standard dipole.

Antenna gain

Antenna gain, also known as antenna directivity, is the relative gain of the main beam of an antenna pattern to a reference antenna, usually an isotropic or standard dipole.

AP: Access point

Access points act as a central transmitter and receiver of WLAN radio signals. Access points used in home or small business networks are generally small, dedicated hardware devices featuring a built-in network adapter, antenna, and radio transmitter. Access points support Wi-Fi wireless communication standards.

APC: Automatic Power Control

Automatic Power Control (APC) is a technique of measuring the performance of a radio channel and adjusting the power of the transmitter to a level appropriate for link characteristics.

APCM: Adaptive Pulse Code Modulation

Adaptive Pulse Code Modulation (APCM) is a technique used to share occupied bandwidth among a maximum number of subscribers during peak times by reducing the signal sampling rates of each subscriber.

APS: Application Support

Application Support (APS) is a sublayer in the ZigBee protocol stack. The responsibilities of the APS sub-layer include maintaining tables for binding to match two devices together based on their services and their needs, and forwarding messages between bound devices. The APS sub-layer is also responsible to determine the responsibilities of the ZDO, to initiate/respond to binding requests, and to establish a secure relationship between network devices.

ARCH: Access Response Channel

Access Response Channel (ARCH), a logic sub-channel of SPACH specified in IS-136, carries wireless system responces from the cell site to the user equipment.

ARDIS: Advanced Radio Data Information S

Advanced Radio Data Information Service (ARDIS) is a wireless two-way data network jointly owned and operated by Motorola and IBM.

ARFCN: Absolute Radio Frequency Channel

Absolute Radio Frequency Channel Numbers (ARFCN) is a channel numbering scheme used to identify specific RF channels in a GSM radio system.

ARIB: Association of Radio Industries an

Association of Radio Industries and Businesses (ARIB) is the Japanese standards-setting organization.

ARQ: Automatic Repeat Request

Automatic Repeat Request (ARQ) is a communication protocol in which the receiving device detects errors and requests retransmissions. When the receiver detects an error in a packet, it automatically requests the transmitter to resend the packet. This process is repeated until the packet is error free or the error continues beyond a predetermined number of transmissions. ARQ is sometimes used with Global System for Mobile (GSM) communication to guarantee data integrity.

ASN: Access Service Network

Access Service Network (CSN), a concept in the mobile WiMAX network, provides full mobility, seamless handoffs, Quality of Service, security and subscriber/connection/resource management.

Attenuation

Attenuation refers to decreasing in signal magnitude between two points. These points may be along a radio path, transmission line or other devices.

Attenuator

Attenuator is a device specifically designed to decrease the magnitude of a signal transmitted through it.

AUC: Authentication Center

The Authentication Center (AUC) is a device, usually located in the HLR of a GSM system, to authenticate each SIM card that attempts to connect to the GSM core network (typically when the phone is powered on). Once the authentication is successful, the HLR is allowed to manage the SIM and services described above. An encryption key is also generated that is subsequently used to encrypt all wireless communications (voice, SMS, etc.) between the mobile phone and the GSM core network.

Average power

Average power is the peak power averaged over time and is usually applied to pulsed systems where the carrier power is switched on and off.

AWGN: Additive White Gaussian Noise

Additive White Gaussian Noise (AWGN) is the statistically random radio noise characterized by a wide frequency range with regards to a signal in a communications channel.

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