Suppose that you have two nodes communicating with an AP that are hidden terminals to one another. The AP, except for
acknowledgments, remains silent and there are no other transmitters in the network. The two nodes are both transmitting packets whose active airtime (time spent sending bits, not waiting) is 1020 microseconds. A node waits 100us for an acknowledgment. Therefore, after transmitting a packet, if no acknowledgment is received, the idle time before a retransmission will be the 100us + the backoff. The network is configured to have an initial CSMA/CA backoff of 0-100 microseconds.
This backoff value doubles for each retransmission (0-100us, then 0-200us, then 0-400us). Assuming both nodes start
transmitting at exactly the same time, what is the minimum number of backoffs before a packet is delivered successfully?
