TABLE OF CONTENTS Logical channels are a portion of a physical communications channel that is used to for a particular (logical) communications purpose. The physical channel may be divided in time, frequency or digital coding to provide for these logical channels. The GSM system has two key types of channels; traffic channels and control channels.
Channels can be shared by multiple users (common channels) or the can be used for one-to-one communication (dedicated channels).
Traffic channels are the combination of voice and data signals existing within a communication channel.
A traffic channel is the combination of voice and data signals existing within a communication channel. There are three basic types of traffic channels; full rate, half rate and eighth rate. Variants of these channels also exist.
A full rate traffic channel (TCH/F) dedicates one slot per frame for a communication channel between a user and the cellular system. A half rate traffic channel (TCH/H) dedicates one slot per every two frames for a communication channel between a user and the cellular system. The eighth rate traffic channel (TCH/8) is used only on the SDCCH for exchange of call setup and/or short message service, to provide limited data transmission rates.
Control channels are a communication channel in system (such as a radio control channel) that is dedicated to the sending and/or receiving of controlling messages between devices (such as a base station and a mobile radio). On a mobile radio system,...
