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It is a multiple-access method in which the available bandwidth of a link is shared in Time, Frequency or through Code.

(i) Frequency Division Multiple Access (FDMA) :-
       Its available Bandwidth is divided into frequency bands. Each station is allocated a band to send its data it belongs to the station all the time.

(ii) Time-Devision Multiple Aceess (TDMA) :-
       In this method the stations share the bandwidth of channel in TIME. Each station is allocated a time slot during which it can send data
[ IMP:- In TDMA, the bandwidth is just one channel that is timeshared between different stations.]

(iii) Code- Division Multiple Access (CDMA) :- 
         In this method, one channel carries all transmission simultaneously.
CDMA means communication with different codes.

How communication with codes takes place :-
(i) If codes are multiply with each other, then the ans. is '0'
(ii) If codes are multiply by itself, then we get 4 [no of station].
Station 1→C1             
Station 2→C2             C2⛌C2 = 4
C1╳C2 = 0

Station 1→d1→C1⇒ C1⛌d1
Station 2→d2→C2⇒ C2⛌d2
Station 3→d3→C3⇒ C3⛌d3
Station 4→d4→C4⇒ C4⛌d4

(C1⛌d1) + (C2⛌d2) + (C3⛌d3) + (C4⛌d4) ----> on a single channel

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