 |
 |
 |
 |
 |  |
4G History
The most common analog system is FDMA, or, Frequency Division Multiple Access. It is a method where the spectrum is cut up into different frequencies and then this chunk given to the users. At one time only one user is assigned to a frequency. Because of this the frequency is closed, until the call is ended, or it is passed on to another frequency. For a proper call to take place, two frequencies are needed, one for sending and one for receiving, FDMA has been used for first generation analog systems only, this is due to the large bandwidth wastage highlighted above.TDMA, or Time Division Multiple Access makes use of the whole available spectrum, unlike FDMA. Instead of splitting the slots by frequency, it splits them by time, over all of the frequency. Each subscriber is given a time slot, as opposed to a frequency. Therefore many uses can sit on one frequency, and have different time slots, because the time slots are switched so rapidly, it seems like the channel is permanently connected. TDMA is used for 2G networks
Next >>