## Example of a TDMA system (cont.)

The GSM frame format is such that eight users are assigned to the same transmission frequency, and hence eight time slots are provided in each frame, to be repeated regularly in subsequent frames. Each user must transmit information at a rate of 270 kbps within the 200 kHz bandwidth allowed (GMSK is used), even though the individual user data rate from the voice coder is only 13 kbps. The throughput of each modem is thus much higher than required to support the users' data, and hence one could expect the design to be much more complicated and costly than an FDMA equivalent. This need not be the case, however, if proper advantage is taken of the fact that the data can be stored and processed 'at leisure' over the seven remaining time slots as well as during the arrival time slot. |

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