Multiple Access Techniqe :
It is used because the limitation of transmission resources comparing with the number of users.
- Three types of Multiple Access Technique are available:
Frequency Division Multiple Access (FDMA).
Time Division Multiple Access (TDMA).
Code Division Multiple Access (CDMA).
- Frequency Division Multiple Access (FDMA)
Each FDMA user is assigned a specific frequency channel. No one else in the same cell or a neighboring cell can use the frequency channel while it is assigned to a user.
Although this technology will reduce signal interference,
it also severely limits the number of users able to transmit at a time.
- Time Division Multiple Access (TDMA)
TDMA users share a common frequency channel, but use the
channel for only a very short amount of time.
They are each given a time slot and only allowed to transmit during that particular time slot.
When all available time slots in a given frequency are used, the next user must be assigned a time slot on another frequency.
The time slices are so small that the human ear cannot perceive the time slicing, and therefore assumes that they have the entire channel to transmit their signal.
- TDMA VS FDMA
- Code Division Multiple Access (CDMA)
CDMA users share a common frequency channel.
All users are on the same frequency at the same time. However, each pair of users is assigned a special code that reduces interferences while increasing privacy.
TDMA VS FDMA VS CDMA
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