|mobile phone communication using multiple access technologies|
Taking aside other different multiple access technologies, there are three FDMA, TDMA and CDMA highly being used and acclaimed.
FDMA--The available frequency range is divided in to frequency slots and each slot is provided to each user or for purposes. 1G was totally based on this technology.
TDMA--Similar to FDMA, but here available time frame is divided in to a limited time slots and in each slot data of different user are trasmitted. Europe used this technique to develop GSM, 2G standard mobile.
CDMA–Neither frequency nor time are used, rather code to transmit data of different users within a wideband. North America used the technique to develop IS-95, 2G standard mobile.
It may seem tuff to understand these technologies in such above language. These all techniques are being used by us in our life unknowingly.
FDMA--Whatever one needs something, give him a portion of something. In fdma case, something is frequency as a channel. This is the simple and easy process that we are using in our daily life since when fdma term wasn’t in existence.
If there is a dance party, and three boys need to be danced with lady, then ? If each boy is provided each lady then that would be FDMA. But be noticed that 3 girls are needed here. In tdma, however, only one girl is sufficient. How ? I will tell you.
TDMA–If a girl do dance with a boy and after some time she do with another, then ? means she divides the time of dancing in 3 time slots and in each time slot she do dance with each boy. After doing dance with 3rd boy, she repeats it with first boy. This is TDMA means division of time.
Another best and perfect example is distribution of card in card playing(तास). In one round, one sample of card for each is distributed and in another round one more card is added for each. In which way cards are distributed in the same way tdma works.
CDMA–If in a convention hall, people have gathered and doing gossips in different languages(code) then that would be a example of cdma. No one can understand the language(code) instead the listener and spokeperson. There seems noise, though all are doing conversation without any feeling of noise.
Another best and perfect example is the security code based process of Western Union Money Transfer to transfer money from one region to another. Such tranfer company uses 10 digits which is just alike wideband for cdma. Depending on the 10 digit, a unique code for each transaction is made and all processes of money reception now will depend on that code. Cdma code concept exactly matches with such activity.