TDMA - Time Division Multiple Access

Time Division Multiple Access (TDMA) is a channelized resource sharing technology whereby a FDMA carrier pair is additionally divided in time also called time slots. TDMA is used in digital communication systems where the information flow of a given user, in the form of data frames, is conveyed in a succession of bursts inside the time slots dedicated to the transmission. This allows multiple users to share the same FDMA channel pair thus dramatically increasing the system capacity. To distinguish between the different active users their data streams are structured in logical channels. The sequence of the assigned times slots to a conversation is dynamic and can greatly improve the service quality.

TDMA should always be considered in tandem with FDMA. The size or duration of the time slots will determine the system capacity and have a direct impact on the channel bandwidth of the FDMA carrier pairs. The higher the number of time slots per carrier the greater the required carrier bandwidth. For instance, in Motorola's iDEN (Integrated Digital Enhanced Network) the TDMA is defined with three time slots per FDMA carrier of a 25kHz bandwidth, while in GSM (Global System for Mobile Communication) the TDMA is defined with eight time slots per FDMA carrier requiring a bandwidth of 200kHz.

The introduction of TDMA to wireless telecommunication has paved the way for the adoption of numerous innovative services and the rethinking in the design of hand-held devices.

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