FDMA - Frequency Division Multiple Access

By: Preethi Ramkumar

Meaning of FDMA - "Frequency Division Multiple Access", is the division of the frequency band allocated for wireless cellular telephone communication into many channels, each of which can carry a voice conversation or, with digital service, carry digital data. FDMA is a basic technology in the analog Advanced Mobile Phone Service (AMPS), the most widely-installed cellular phone system installed in North America. With FDMA, each channel can be assigned to only one user at a time. FDMA is also used in the Total Access Communication System (TACS).

The Digital-Advanced Mobile Phone Service (D-AMPS) also uses FDMA but adds time division multiple access (TDMA) to get three channels for each FDMA channel, tripling the number of calls that can be handled on a channel. frequency-division multiple access (FDMA): The use of frequency division is to provide multiple and simultaneous transmissions to a single transponder. The other two methods are Time Division Multiple Access (TDMA) and Code Division Multiple Access (CDMA).

In FDMA, each transmitter is assigned a distinct frequency channel so that receivers can discriminate among them by tuning to the desired channel. TDMA and CDMA are always used in combination with FDMA, i.e., a given frequency channel may be used for either TDMA or CDMA independently of signals on other frequency channels.

In 1989, the Cellular Telecommunications Industry Association (CTIA) chose TDMA over Motorola’s frequency division multiple access (FDMA) (today known as narrowband analog mobile-phone service [NAMPS]) narrowband standard as the technology of choice for existing 800 MHz cellular markets and for emerging 1.9-GHz markets. With the growing technology competition applied by Qualcomm in favor of code division multiple access (CDMA) and the realities of the European global system for mobile communications (GSM) standard, the CTIA decided to let carriers make their own technology selection.

Other Related Definitions:

"The early cellular networks used an analog transmission protocol (called frequency-division multiple access - FDMA), in which speech frequency modulates a continuous wave carrier. In the USA these cellular systems operate in the 824 - 894 MHz frequency range (824-849 MHz for the mobile/hand-helds and 869-894 MHz for the base stations), which was formerly allocated to UHF television channels 69-84. At the beginning of the 1990s these systems were reaching the limits of their capacity in many service areas. This led to..."[FREQUENCIES AND OPERATING PROTOCOLS OF CELLULAR WIRELESS COMMUNICATION SYSTEMS - IEEE] 

“…FDMA Frequency Division Multiple Access – together with TDMA and CDMA this is a technique whereby a transmission channel is used by more than one subscriber. The basic principle is that the available frequency range is divided up into several sub-ranges ('partial bands'), which are then assigned to different subscribers. ." [SIEMENS –Mobile Networks Portal] 

"Frequency Division Multiple Access is a technique used for dividing a band of radio frequencies into individual channels that can be assigned to calls over f wireless networks. AMPS, GSM and TDMA networks all rely on FDMA in varying degrees.." [T-Mobile USA ]

Related Links:

FDMA vs TDMA vs CDMA:   What's the difference?
The History of Multiple Access : Future of Multiple Services.
MULTIPLE-ACCESS TECHNIQUES – Technique used in third generation wireless systems.
FDMA used in radio frequency – Information about FDMA respect to radio channels.
Used in Analog Systems – A Technical information about FDMA.
Various Options in Access Methodologies -FDMA method for design and Devolopment

Products and Solutions:

Circuits and Systems – Aims and Objectives
MODEL FOR DATA TRANSMISSION IN THE GSM SYSTEM – Provides research on FDMA
Cisco Systems – Technology designed for high speed data cable
Electronic design – A new approach to FDMA
DSCS FDMA Control System - How FDMA is used in space research

Books About:

Study of advanced communications satellite systems based on SS-FDMA - By John Kiesling
A Comparison Study of CDMA Versus TDMA/FDMA Leo Satellite Systems - By Timothy M. Ciocco

See Also:

FDMA Resources

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