Question

Problem # 5. Yet another variation: A better packet switched network employs the concept of acknowledgment. When the end user’s device receives a packet correctly it sends an acknowledgment to the sender. Here too, a packet is received correctly with probability p, but the sender keeps sending copies of a given packet until a copy is correctly received (signaled by acknowledgment). Let random variable N be the number of times the same message packet is sent.

a) Find the PMF PN (n).

b) To avoid excessive delays (too many repeated transmissions of same packet), it is required that the network maintain P[N < 4] > 0.95. Find the minimum value of p that will satisfy this requirement

Answer 1