Friday, 20 November 2009

Celluar Radio,Circuit Switching,CLDC

Cellular Radio
The technology that has made large scale mobile telephony possible. Current cellular networks reuse the same radio frequencies by assigning them to cells far enough apart to reduce interference. A cell is the geographical area covered by one radio base station transmitting/receiving in the center. The size of each cell is determined by the terrain, transmission power, and forecasted number of users. Service coverage of a given area is based on an interlocking network of cells, called a cell system.
Circuit-Switching
Means of creating a connection by setting up a dedicated end-to-end circuit, which remains open for the duration of the communication.
CLDC
J2ME Connected Limited Device Configuration. The CLDC serves the market consisting of personal, mobile, connected information devices. This configuration includes some new classes designed specifically to fit the needs of small-footprint devices.
Communicator
A generic name for information centric mobile phones. In effect a fully featured personal digital assistant and mobile phone in one unit. The Nokia 9210 Communicator is an example of such a Symbian OS phone.
Content Provider A company that provides services to mobile phone users or network operators. These services could be shopping, web surfing, chat rooms, playing games, accessing data such as music and books through a server.
Crystal
Code-name for a half VGA reference design for Symbian OS.
D-AMPS
Digital AMPS (Digital-Advanced Mobile Phone Service) is the digital wireless standard widely used throughout the Americas, Asia Pacific and other areas. D-AMPS uses digital TDMA on the one hand, and is required to be compatible with installed AMPS base station networks on the other. D-AMPS operates on the 800 and 1900 MHz bands.
DCS
1800 Digital Communications System: another name for GSM working on a radio frequency of 1800 MHz. Also known as GSM1800 or PCN, this digital network operates in Europe and Asia Pacific.
Digital
A way of encoding information. On digital networks, data doesn't need to go though the extra step of being converted to an analog signal, voice is sampled and coded in a way similar to how it is recorded on a CD. Digital networks are fast replacing analog ones as they offer improved sound quality, secure transmission and can handle data directly as well as voice. Digital networks include mobile systems GSM, D-AMPS, CDMA, TDMA and UMTS.

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