Question

7. A large population of ALOHA users manages to generate 60 requests/s, including originals and retransmissions. Time is slotted in units of 50 ms. (Page 265 in the book may provide some help with this question.) (12 pts) a) What is the chance of success on the first attempt

Answer 1

P(success at first attempt) = 0.1353

Explanation:

This question follows poisson distribution. Thus, the formula is;

P(k) = (e^(-G) × (G)k)/k!

where;

G is number of frames generated in one frame transmission time(or frame slot time)

Let's find G.

To do this, we need to find number of frames generated in 1 slot time which is given as 50 ms.

Now, in 1000 ms, the number of frames generated = 50

Thus; number of frames generated in 50 ms is;

G = (50/1000) × 50

G = 2.5

To find the chance of success on the first attempt will be given by;

P(success at first attempt) = P(0) = e^(-G) = e^(-2) = 0.1353