FDMA->bandwidth is divided in to channel,synchronization is not possible,guard band is required,codeword is not required.
TDMA:->it is just channel that is time is shared,synchronization is required,guard time is required,codeword is not required.
CDMA:->sharing of bandwidth and time,synchronization is not required.guard band and guard time is required.,codeword is required.
BY SANTOSH SINGH ARA SMEC CSE LOVE...
FDMA, as the name implies operates by dividing the bandwidth of the wireless channel equally among a number of users wanting to access the channel.ie frequency division multiple access. It was the first technology used.
TDMA was the next to come, it was the opening of digital world. It had an attractive feature that it does accommodate the transmission of source channel encoded digital data alongside digitized speech in straightforward manner. With TDMA channel bandwidths are wider than FDMA and fading is no longer frequency flat, but rather frequency selective. IT is time division multiple access.GSM was from this global system for mobile; it has frame structure with 8 time slots.
CDMA refers to a multiple-access technique in which the individual terminals use spread spectrum technique and occupy all the spectrum whenever they transmit, it is the interference attenuation property of the spread-spectrum that allows multiple users to occupy the same spectrum at the same time. It is the coded division multiple access it uses the coding.
CDMA has greater capacity.
TDMA and FDMA have a fixed no. Of slots.
Frequency can be reused in each cell in CDMA.
No hard limit to no. Of users.
Resistance to multiple fading.