Time slots are the smallest division of a communication channel that is assigned to particular users in a communication system. Time slots can be combined for a single user to increase the total data transfer rate available to that user. In some systems, time slots are assigned dynamically on an asneeded basis.

Slot structure is the division of a time slot into different fields (information) parts. Slot structure fields typically include a preamble for synchronization, control header (e.g. address information), user data, and error detection.

The time period for a GSM time slot is 577 microseconds. The number of data bits in a time slot depending on the type of the time slot (user data or control). The structure of the time slot can also vary dependent if the time slot is on the uplink or downlink radio channel. Each normal time slot contains 148 bits of information. Some time slot data bits are used for user data and others bits are dedicated for control.

The time slots are numbered from 0 to 7. For voice communication, users have a fixed assignment of particular time slots. For packet data transmission (such as GPRS), time slots are dynamically assigned.

Time slots include ramp up and ramp down periods to minimize rapid changes in radio transmitter power. The ramp up and ramp down time to reduce unwanted radio emissions that occur from rapidly changing signals.

A single time slot transmission is called a radio burst. Four types of radio...