Overview

Radio access is method used by mobile radio systems to coordinate service requests and share radio channel usage is through the use of system access technologies. System access technologies are the language of radio. Mobile radios can communicate with a system, as long as the system can understand their language. System access technologies are commonly defined by their modulation type, timing and information characteristics. There are three basic ways that allow radios to share access to radio channels; frequency division, time division and code division multiplexing.

There are two basic functions for radio channels used in radio access systems, control and communication. Control involves the coordination between transmitters and receivers so they can request service and avoid interference with each other. Communication involves the transfer of information content (voice or data) between two points. These channels may allow only one user at a time to send information or they may be divided to allow the sharing (multiplexing) of the radio channel by multiple radios at the same time.

When a radio channel is exclusively used to coordinate access to other radio channels, it is called a control channel or a signaling channel. When a radio channel is used to transfer information between radios, it is called a voice or traffic channel. Some radio access technologies combine control and communication on the same RF channel.

Each radio communication channel is typically divided into several sub channels. The radio channel is typically called a "communication channel" and each sub-channel is called...