What is TDMA & FDMA in 4G Network?

TDMA and FDMA form part of the telecom technology. I am trying to put the ideas in a simple language here -

FDMA
FDMA stand for Frequency Division Multiple Access. In this, the total bandwidth available is divided into multiple frequencies. It finds usage in analog communication. Though it can handle digital transmission, it may not be that much effective means in that direction. This technology will have only one user at a particular time on one channel. All the information will be contained in a single channel.

TDMA
This is an acronym for Time Division Multiple Access. The transmission happens on a single digital channel. The calls are digitised and then sent on a single channel. TDMA will let three users occupy a single channel at the same time. They will be using it in quick succession that will be unnoticeable.

TDMA and FDMA are one of the resource sharing implementations in the telecom network. Here's the explanation for each of them in simple way.

TDMA Time division multiple access TDMA is a method of communication. Here each user connected to the nearby tower gets specific time block for transmit and reception. The separation of the type of data transfer and congestion are handled differently in both 3G and 4G networks. Considering the networks are using digital transmission, the data and voice signals are lot clear and have less noise compared to old analog signals using same technology.

FDMA Frequency division multiple access FDMA is a method of communication where frequency slots are divided for each user on resource sharing model. It is one of the oldest method in the telecom communication. In earlier days the signal divided was analog hence had lossy transmission for audio and data. In modern days digital transmission has reduced the signal loss and hence improve voice and data communication in lossless way.

Do note that marketing people are promoting 3G and 4G as if it's some advanced technology. Underlying process for 3G however is still CDMA that makes use of either TDMA or FDMA or both. In case of 4G the networks make use of LTE that comprises of OFDMA and SC-FDMA. There is nothing ground breaking research on 2G, 3G, 4G as of yet, they are still making use of DMA (division multiple access) since analog days, only with difference of digitization that can serve larger number of users for a given band in specific tower region.

FDMA and TDMA basically differs in the way the channel is used.

FDMA
FDMA stands for Frequency Division Multiple Access.This technique divides the whole bandwidth of the channel in segments and provides that to the users. The users can access the same channel at the same time but only using the bandwidth provided to them.

TDMA
TDMA stands for Time Division Multiple Access. This type of division technique use time division technique to divide the same frequency among the users. The shuffling of the time is designed in such a way between the user that they don't even know that they are sharing the same frequency with others. Time frame is the key factor here between the users and they share the same frequency using time bonds.