Preamble TDMA Explaination
Preamble based TDMA:
There are different time slots to send and recv data
NS only supports single hop preamble based tdma
Each node has a dedicated subslot to broadcast the destination id of the outgoing packet
Other nodes listen in the preamble and record the time slot to recv data
There is a separate preamble and data transmission phase
Lets us consider 4 nodes where:
Node 1 wants to send data to node 3
Node 2 wants to send data to node 1
Node 3 wants to send data to node 2 and
Node 4 has no data to send
Preamble phase
According to point 3, during the preamble phase each node will put the destination id of the outgoing packet in its dedicated slot in the preamble
According to point 4, each node will record the time slots in which it has to recv data in the preamble phase
Node 1 recorded that it has data to recv in slot 2
Node 2 recorded that it has data to recv in slot 3 and
Node 3 recorded that it has data to recv in slot 1
Data transmission phase
Node 1 will put the data to send in slot 1
Node 2 will put the data to send in slot 2
Node 3 will put the data to send in slot 3
Hence proving point 1 i.e.
Node 1 used slot 1 to send data and slot 2 to recv data
Node 2 used slot 2 to send data and slot 3 to recv data
Node 3 used slot 3 to send data and slot 1 to recv data