- Recall:
- The binary exponential back off algorithm
has the
channel capture effect
- The bin. exp. back off algorithm is unfair to node that perform frequent retransmissions
See: click here
- The binary exponential back off algorithm
has the
channel capture effect
- Improving fairness:
- Fairness fix:
- The 802.11 protocol do not allow a node to transmit frame continuously
- After each successful
transmission, a
node will perform a
back off
- The node "tries" to allow (let) nodes that are currently waiting (= performing count down) to transmit before it,
See:
- Hopefully,
this will alleviate
the channel capture phenomenon
(because other senders would have
larger back off periods and
the current sender will keep winning...)
- This is only a band-aid remedy - providing fairness in 802.11 is an active research area...
- Fairness fix:
- 802.11 MAC: click here