802.11 Protocol Architecture
CW increases exponentially for retransmissions (unique per station) to
minimize collisions and maximize throughput for both low and high
network utilization. Under low utilization, stations are not forced to
wait very long before transmitting their frame. On the first or second
attempt, a station will make a successful transmission within a short
period of time. If the utilization of the network is high, the protocol
holds stations back for longer period of times to avoid the probability
of multiple stations transmitting at the same time.
FIGURE 2.14
Contention Window values
Under high utilization, the value of CW increases to relatively high
values after successive retransmissions, providing substantial
transmission spacing between stations needing to transmit. This
