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Cellular Telecommunications Glossary [A - E]

- a glossary of terms used with cell phone or cellular telecommunications technology

Glossary pages: [ 0 - 9 ] , [ A - C ] , [ D - F ] , [ G - J ] , [ K - N ] , [ O - S ] and [ T - Z ]


A-bis –
The standard for the link between the base transceiver station and the base-station controller.
ACELP - Algebraic Code Excited Linear Prediction
A vocoder used in GSM and NA-TDMA.
AFLT - Advanced Forward Link Trilateration.
A position location technique used on CDMA networks. It uses the measured time of arrival of radio signals to the mobile from the base stations. Using this information the network is able to determine the location of the mobile to an accuracy of around 200 metres.
A-GPS - Assisted GPS.
A position location technique used for cellular telecommunications that is based around the Global Positioning System (GPS). To provide a faster time to first fix and signal acquisition under poor signal conditions, assistance data is provided by the network to the mobile.
AMPS - Advanced Mobile Phone System.
The first generation analogue cellular system used in North America and many other countries around the globe. It used a 30 kHz channel spacing, and FM was used to carry the voice channel.
ARIB - Association of Radio Industries and Businesses.
The body responsible for telecommunications standards in Japan.
ARPU - Average Revenue Per User.
The figure for the average revenue generated by each user on a mobile phone network.
AuC - Authentication Centre.
It contains secure information about subscribers to a network including the permanent key of the subscriber’s SIM card. This information enables it to provide authentication and encryption parameters that verify the user's identity and ensure the confidentiality of each call protecting users and network operators from fraud.
AT - Access terminal.
This refers to the handset or “phone” used on a CDMA2000 1xEV-DO network. It is called an Access Terminal because EV-DO is a data only service.
AWGN - Additive White Gaussian Noise.
An emulation of “white” noise often used in testing receiver sensitivity. It is also used for testing CDMA systems because the noise simulates that which is generated by additional CDMA signals on the same channel.
Baseband -
The signal or signals that are used to modulate the radio carrier in the transmitter, and in this way the information can be carried by the radio signal. They may often be referred to as modulation. The baseband signals are recovered by the receiver by demodulating the received radio signal.
BSC - Base Station Controller.
Mobile network component that contains all the logic used to control the operations of the BTS and acts as an interface between the BTS and the MSC.
BTS - Base Transceiver Station.
The term for a mobile phone base station. A BTS contains the transmit and receive technology and also the antennas to supply a cellular radio cell.
CDG - CDMA Development Group.
This is the consortium of companies that was formed to promote the adoption, development and evolution of CDMA (i.e. cdmaOne and CDMA2000) wireless technology.
CDMA - Code Division Multiple Access.
A cellular telecommunications access technology using direct sequence spread spectrum techniques. By using DSSS it enables multiple users to gain access to a network by allocating them different spreading codes.
CDMA2000 –
This is a family of 3G cellular telephone standards. It includes CDMA2000 1X and beyond this the CDMA2000 1xEv, evolution technologies that offer higher data rate services.
CDMA2000 1X -
The first phase of CDMA2000 offering voice and data services. Peak data rates of 307 kbps can be achieved using a single channel and when two are used this increases to 614 kbps.
CDMA2000 1xEV -
The Evolution of CDMA2000 beyond 1X offering higher data rates. The two schemes that are currently live or being developed are CDMA2000 1xEV-DO and CDMA2000 1xEV-DV.
CDMA2000 1xEV-DO -
This is the Data only or Data Optimised evolution for CDMA2000. As the name implies this standard is optimised for data only and can offer data rates up to 2.45 Mbps under Release 0 of the standard or 3.1 Mbps under Release A. It uses separate channels from the existing 1X standard, and if voice traffic is to be handled an “Access Terminal” capable of using 1X must be used and this is carried on a different channel to the data. The EV-DO standard is defined under IS-856.
CDMA2000 1xEV-DV -
This the Data and Voice evolution for CDMA2000. It supports both data and voice on the same channel and data speeds of up to 3.1 Mbps can be achieved. The system is defined under IS-2000. The first offering appears in Release C of the standard where the high data rate is only available in the downlink, the uplink allows for data at the same rate as 1X. Release D allows for the high speed data in both directions.
cdmaOne -
This is the brand name for the second-generation CDMA system defined under the IS-95 standard. It operates in the 800 MHz or 1.9 GHz radio frequency bands and uses 1.25 MHz-wide channel bandwidth.
CELP -
Code Excited Linear Prediction. An digital voice coding scheme that predicts the signal using past samples.
CEPT -
The European Conference of Postal and Telecommunications Administrations (Conférence Européenne des Administrations des Postes et des Telecommunications). It is the European telecommunications authority and it exclusively addresses sovereign/regulatory matters for postal and telecommunications activities within Europe.
Chip -
A single bit of a pseudonoise sequence.
Chip rate -
The rate at which chips are sent. For CDMA networks where signals need to be spread over bandwidths of 1 MHz and more chip rates are measured in millions of chips per second, Mcps.
Churn –
This is the term for subscribers leaving one cell phone operator to go to another.
Circuit switched data –
This is the technique that is used when a complete circuit is dedicated to a particular data channel. The destination address is implicitly defined by the circuit that is selected. It offers a simple solution to sending data over a channel, although it is not as efficient as packet switched data because channel usage can be low and the channel cannot be shared.
CODEC - COder/DECoder.
A circuit used to convert analogue signals such as voice or video into a digital format for transmission over digital medium. A the receiver it also reconverts the signals to the original analogue form. The circuit or algorithm used may also include compression and decompression to reduce the level of data that needs to be transmitted. Codecs are widely used in mobile phones and different coding algorithms used dependent upon the phone system used and the application.
COFDM - Coded Orthogonal Frequency Division Multiplex.
A modulation scheme using a number of closely spaced orthogonal carriers. The data is spread oer these carriers and as a result it is resilient to multipath and other forms of interference. It is used for various forms of digital broadcasting and is being considered for the use with the fourth generation cellular telecommunications systems.
Correlation -
This is a process that occurs when using spread spectrum techniques and it is the process of synchronizing the phase of a local PN sequence within a radio receiver with that of the incoming spread signal in order to “despread” and recover the narrowband data signal.
CTIA - Cellular Telecommunications and Internet Association.
It offers many services including operating an equipment testing and certification program.

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