Channelization Protocols

Channelization Protocols

Channelization or some times called channel Partition(Division) is a multiple access method in which the available bandwidth of a link is shared in respect with the time , frequency or through codes. It is a channelization protocol that allows the total usable bandwidth in a shared channel to be shared across multiple stations based on their time, distance and codes. It can access all the stations at the same time to send the data frames to the channel. There are three channelization protocols which are as follows : FDMA, TDMA and CDMA.

FDMA (Frequency Division Multiple Access)

This method is used to divide the available bandwidth into equal frequency bands by which multiple users can send data through a different frequency to the subchannel. Each station is allocated a band to send its data.In other words, each frequency bands is reserved for a specific station. Each station also uses a band pass filter to confine the transmitter frequencies. To prevent station interference, the allocated bands, are separated from one another by using a small guard bands. Small guard can reduce the cross talk only not remove it. 

TDMA (Time Division Multiple Access)

In Time division Multiple Access method, the stations share the bandwidth of the channel in time. Each station is allocated a time slot during which it can send the data. Each station transmits its data in its assigned time slot.

No Guard Band are required in the Time Division Multiple Access.  

CDMA (Code Division Multiple Access)

In CDMA, all stations can simultaneously send the data over the same channel. It means that it allows each station to transmit the data frames with full frequency on the shared channel at all times. It does not require the division of bandwidth on a shared channel based on time slots. If multiple stations send data to a channel simultaneously, their data frames are separated by a unique code sequence. Each station has a different unique code for transmitting the data over a shared channel. For example, there are multiple users in a room that are continuously speaking. Data is received by the users if only two-person interact with each other using the same language. Similarly, in the network, if different stations communicate with each other simultaneously with different code language.