Time Division Multiple Access (TDMA)

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 GSM uses Time Division Multiple Access (TDMA) as its access scheme. This is how the MS interfaces with the network. TDMA is the protocol used on the Air (Um) Link. GSM uses Gaussian Minimum-Shift Keying (GMSK) as its modulation methods.
Time Division means that the frequency is divided up into blocks of time and only certain logical channels are transmitted at certain times. Logical channels will be introduced in the next lesson. The time divisions in TDMA are known as Time Slots.


Time Slots : A frequency is divided up into 8 time slots, numbered 0 to 7.




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