According to Wikipedia, FDMAAi??aka “Frequency Division Multiple Access” is an access method that is used by radio systems to share the radio spectrum. The terminology ai???multiple accessai??? implies the sharing of the resource amongst users, and the ai???frequency divisionai??? describes how the sharing is done: by allocating users with different carrier frequencies of the radio spectrum.
With FDMA, the given Radio Frequency (RF) bandwidth is divided into smaller frequency bands called subdivisions. Each subdivision has its own carrier frequency. A control mechanism is used to ensure that two or more earth stations do not transmit in the same subdivision at the same time. Essentially, the control mechanism designates a receive station for each of the subdivisions.
This source also explainsAi??TDMA or “Time Division Multiple Access.”Ai??This is an access method that is used by radio systems to share the radio spectrum. The terminology, ai???multiple access,ai??? implies the sharing of the resource amongst users while the ai???time divisionai??? describes how the sharing is done: by dividing and allocating users into different timeslots in a carrier frequency of the radio spectrum.
TDMA is used in the Global System for Mobile Communications (GSM) and Personal Digital Cellular (PDC). It is also used extensively in satellite systems, local area networks, physical security systems, and combat-net radio systems. This means that two way radios and cell phones utilize this technology as well.
Ai??TDMA is a type ofAi??time-division multiplexing, with the special point that instead of having oneAi??transmitterAi??connected to oneAi??receiver, there are multiple transmitters. In the case of theAi??uplinkAi??from aAi??mobile phoneAi??to abase stationAi??this becomes particularly difficult because the mobile phone can move around and vary thetiming advanceAi??required to make its transmission match the gap in transmission from its peers.
Both of these technologies are utilized in the two-way radio industry, so it is important to note the ways in which these influence communications. With the knowledge and understanding of how these methods work, new products are able to evolve.