Channel Access Method

In cellular system, there are 3 basic method for user to access channel for establishing a connection :

• FDMA (Frequency Division Multiple Access), divided user by frequency, means each user have its own frequency range to use as a communication channel
• TDMA (Time Division Multiple Access), divided user by time slot, means each user have its own time slot (same frequency range) to use as a communication channel, these time slot is in mili second, so user almost feels nothing while it in a continous connection such as voice call
• CDMA (Code Division Multiple Access), divided user by code, means each user have its own unique code (same frequency range at a same time) to use as a communication channel, so user information is coded before enter the network at source user side and decoded again at target user side

From picture and explanation above, can be known, that TDMA is more advantage than FDMA, and CDMA is more advantage than TDMA

What is a cellular network?

Cellular network, as the picture shown above, is a wireless telecommunication network that divided its service area into cells. Each signal that covers these cells were transmitted by a transceiver station. These cells make sure that any user can roam mobile and have a continous communication with other user, as long as it still in coverage area of the network. These days, there are 2 common Radio Access Transmission (RAT) system that were known and used widely in the world, 2G and 3G. There also 4G, but it still only used in some countries