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Multiple access protocols in Computer Network

 

Multiple access layers are needed to decrease collisions and prevent crosstalk. The protocols can be divided in the following way:

 

 

  • Random Access Protocol

 

In the random access protocol, there is no fixed time or sequence for sending data. 

It can be further divided as:

  1. ALOHA
  2. CSMA
  3. CSMA/CD
  4. CSMA/CA

 

 

  • Controlled Access

 

In controlled access, the data is sent only when it is approved by other stations. 

 

 

  • Channelization

 

The available bandwidth of the link is shared to multiple stations for access at the same time. 

There is:

 

  • Frequency Division Multiple Access (FDMA)

 

In FDMA, the available bandwidth is divided equally so each station can have its own band. 

 

  • Time Division Multiple Access (TDMA)

 

In TDMA, the bandwidth is shared among multiple stations.

 

  • Code Division Multiple Access (CDMA)

 

In CDMA, a single channel carries out all the transmissions simultaneously. 

 

Reference

Multiple access protocols in Computer Network