| 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
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| 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
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| 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.
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| 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.
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| 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).
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| 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.
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| 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.
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| 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.
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| 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).
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| 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.
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| ACIR: Adjacent Channel Interference Rati |
Adjacent Channel Interference Ratio (ACIR) is the ratio of wanted power to the interference power from the adjacent channels.
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| 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.
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| 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.
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| 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.
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| 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.
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| 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.
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| 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.
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| 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.
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| 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.
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| 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.
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| 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.
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| 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.
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| 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.
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| Adjacent channel interference |
Adjacent channel interference refers to signal impairment to one frequency due to presence of another signal on a nearby frequency.
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| 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.
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