| C/I |
carrier-to-interference ratio |
|
| C/N |
carrier-to-noise ratio |
See carrier-to-noise ratio. |
| CAI |
Common Air Interface |
A set of open standards describing the physical and logical characteristics of a link between a base station and mobile station. These standards are used by infrastructure and handset manufactures to design and build equipment that is capable of interoperating with each others systems. |
| carrier |
|
An RF signal that has an information signal superimposed on it through
modulation. Also called a carrier signal. |
| carrier recovery |
|
A technique for extracting the RF carrier from a modulated signal so that it can be reinserted and used to recover the modulating signal. |
| carrier signal |
|
See carrier. |
| carrier-to-interference ratio |
|
The ratio of power in an RF carrier to the interference power in the channel. |
| carrier-to-noise ratio |
|
The ratio of power in an RF carrier to the noise power in the channel. |
| CAS |
Call Associated Signaling |
Signaling required for supervision of a bearer service between two end
points. It includes support for the functions of call origination, call delivery,
and handover. |
| CBCH |
Cell Broadcast Channel |
|
| CCDF |
Complementary Cumulative Distribution Function |
|
| CCH |
Control Channel |
|
| CDF |
Cumulative Distribution Function |
The cumulative probability that a parameter will be less than a given value X. |
| CDG |
CDMA Development Group |
A technical organization dedicated to developing the CDMA technology and promoting its use world-wide. |
| CDMA |
Code Division Multiple Access |
One of several digital wireless transmission methods in which signals are encoded using a specific pseudo-random sequence, or code, to define a communication channel. A receiver, knowing the code, can use it to decode the received signal in the presence of other signals in the channel. This is one of several "spread spectrum" techniques, which allows multiple users to share the same radio frequency spectrum by assigning each active user an unique code. CDMA offers improved spectral efficiency over analog transmission in that it allows for greater frequency reuse. Other characteristics of CDMA systems reduce dropped calls, increase battery life and offer more secure transmission. See also IS-95. |
| cdma2000 |
The name identifying the TIA standard (IS-2000) for third generation technology that is an evolutionary outgrowth of cdmaOne. |
A radio transmission technology for the evolution of narrowband cdmaOne/IS-95 to 3rd-generation adding up multiple carriers. See also W-CDMA for single carrier/direct spread technology. |
| cdmaOne |
|
Brand name describing a complete wireless system incorporating the IS-95 CDMA air interface. |
| CDP |
Code Domain Power |
A measurement of the power contained in each Walsh coded channel in CDMA signals. The CDP measurement is beneficial in troubleshooting CDMA transmitter designs. |
| CDPD |
Cellular Digital Packet Data |
An open wireless transmission standard allowing two-way 19.2-Kbps packet data transmission over existing cellular telephone channels (AMPS with CDPD capability.) In essence, CDPD technology uses idle network capacity caused by pauses in phone conversations and gaps between calls placed, etc. to transmit data. |
| CDVCC |
Coded Digital Verification Color Code |
|
| cell |
|
The geographic area encompassing the signal range from one base station (a site containing a radio transmitter/receiver and network communication equipment). Wireless transmission networks are comprised of many hexagonal, overlapping cell sites to efficiently use radio spectrum for wireless transmissions. Also, the basis for the term "cellular phone." |
| cell splitting |
|
The process of splitting a cell into several smaller cells. This us usually done to make more voice channels available to accommodate traffic growth in the area covered by the original cell. |
| cellular |
|
In wireless communications, cellular refers most basically to the structure of the wireless transmission networks which are comprised of cells or transmission sites. Cellular is also the name of the wireless telephone system originally developed by Bell Laboratories that used low-powered analog radio equipment to transmit within cells. The terms "cellular phone" or "cell phone" are used interchangeably to refer to wireless phones. Within the wireless industry, cellular is also used to refer to non-PCS products and services. |
| cellular handoff |
|
In cellular communications, a telephone call is switched by computers from one transmitter to the next, without disconnecting the signal, as a vehicle moves from cell to cell. The mobile remains on a specific channel until signal strength diminishes, then, is automatically told to go to another channel and pick up the transferred transmissions there. |
| cellular mobile telephone system |
|
System where each geographic area is covered by a base station. This area is known as a cell. Each telephone in the cell communicates with the base station. If the phone moves to another cell, the call is automatically transferred to the base station in the new cell. |
| CELP |
Code-Book Excited Linear Predictive |
|
| CEPT |
Committee of European Posts & Telephones |
A European regulatory body responsible for coordinating telecommunications within Europe. |
| CGSA |
Cellular Geographic Service Area |
A general term used to describe the physical area over which a cellular carrier is licensed to provide service. See also MSA, RSA, MTA, BTA, EA and REAG. |
| channel |
|
A general term used to describe a communications path between two systems. They may be either physical or logical depending on the application. An RF channel is a physical channel, whereas control and traffic channels within the RF channel would be considered logical channels. |
| channel coding |
|
The application of forward error correction codes to an RF channel to improve performance and throughput. |
| CHTML (cHTML) |
Compact HTML |
Version of the hypertext markup language used by NTT DoCoMo's i-mode service. |
| CIF |
Common Intermediate Format |
A video image format using 352 horizontal pixels and 288 vertical lines. The format is adopted in multimedia communication standards. |
| circuit switched |
|
A switched circuit is only maintained while the sender and recipient are communicating, as opposed to a dedicated circuit which is held open regardless of whether data is being sent or not. |
| clock recovery |
|
The process of extracting the timing signals from a digitally modulated carrier wave. The recovered clock signal is then used to decode and further process the data. |
| CODEC |
Coder/Decoder |
An amalgam of the terms "Coder" and "Decoder". It generally signifies the encoding device/module which carries out highly efficient conversion processing from the basic digital signal to a compressed signal during digitalization of voice and picture signals. Encoding specifications for the voice CODEC and image CODEC are stipulated by the G-series and H-series ITU-T recommendations, respectively. In the case of mobile communication, encoding specifications are established by the concerned standardizing bodies. |
| coding gain |
|
The effective gain, usually in dB, that coding provides over an uncoded signal. Coding gain is usually measured as the dB difference in C/N ratios between a coded and uncoded signal producing the same BER. |
| coherent detection |
|
Also referred to as coherent demodulation, this is a technique of phase locking to the carrier wave to improve detection. Knowledge of the carrier phase improves demodulator performance. |
| companding |
Compressing and Expanding |
|
| control channel |
|
A channel, usually logical, used to send administrative and supervisory signals between a base station and a mobile station. |
| core network |
|
In a wireless communications network, the physical infrastructure that
ties together all the radio access equipment. In 1G and 2G networks, the
core network is circuit-switched. In 2.5G and 3G data networks, the core
network will be IP packet-based. |
| core network interface |
|
In 3G UMTS, the terrestrial core network infrastructure connected to the
RAN through the Iu interface; for example, the Internet and the public switched
telephone network (PSTN). The gateway device for this activity is usually
called a mobile switching center (MSC) or mobile multimedia switch. |
| COST-231 |
|
ETSI propagation model for 2 GHz applications. |
| coverage area |
|
The geographical reach of a mobile communications network or system. |
| coverage hole |
|
An area within the radio coverage footprint of a wireless system in which the RF signal level is below the design threshold. Coverage holes are usually caused by physical obstructions such as buildings, foliage, hills, tunnels and indoor parking garages. |
| CPM |
Continuous Phase Modulation |
|
| CRC |
Cyclic Redundancy Code |
|
| CT-2 |
Cordless Telephone 2 |
|
| CT-3 |
|
See DECT. |
| CTIA |
Cellular Telecom Industry Association |
The membership-based association, located in Washington, D.C., represents the interests of the wireless telecommunications industry. |
| CW |
Continuous Wave |
The term commonly gives to an unmodulated RF carrier. |
