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20 December 2017

What is FDMA | Features | Types | Application | Advantages

In a wireless communication system, the individual users are allocated individual channels is called FDMA. It is a channel access method found in multiple access protocol as a channelization protocol. The channel or frequency band is unique for each subscriber.

Definition of FDMA :


Frequency division multiple access is a frequency band. It is one types of channel access method can be divided small frequency channel and also have different channel are allocated to different users. Multiple users can transmit at the same time but on the different frequency channel. 

For detailed information :
Read a more  >> Definition of FDMA

Some useful information :

 

The entire allowed radio spectrum is divided into many slices of the frequency bands and each band or channel is allocated to the user. 

In FDMA system the users are assigned a pair of frequency, one for the forward channel and other for the reverse channel. Because of that they have certain advantages and so the channel allocation can be done on a demand basis to the users to request service and thus call is processed.

Nowadays the advanced digital mobile phone services use in FDMA system but add in TDMA to get three number of channels for each FDMA channel, so tripling the number of calls can be handled on a channel. 


One main disadvantage is crosstalk, which can cause interference between frequencies and interrupt the transmission.



Features of FDMA :

  • The complexity is less.
  • Demands a highly efficient filter.
  • FDMA is not prone to the near-far problem that exists in CDMA because of frequency filtering.
  • Every user receives an individual frequency because all users transmit and receive at different frequencies.
For detailed information : 
Read more >> Features of FDMA


Types of FDMA : 

  • FAMA 
  • DAMA
Fixed assignment multiple access: 

In this method, the channel is assigned in a predetermined manner and distributed so that random changes in the capacity are not allowed. It denoted as FAMA. 

Demand assignment multiple Access: 


If there are multiple stations there is a change of capacity then the channel can be allocated to the demand. It donated as DAMA.

Detailed information : 
Read more >> Types of FDMA 

Applications of FDMA


  • Telephone system
  • Radio system 
  • Cable TV
  • Walkie talkies
  • Mobile network for close user group. Example - WiFi
  • Total access communication systems (TACS)
  • 2G mobile communication
  • GSM uses FDMA in combination with TDMA
  • UMTS in combination with other multiplexing techniques 
Detailed information 
Read more >> Applications of FDMA