Slotted Aloha efficiency
Q: what is max fraction slots successful?
A: Suppose N stations have packets to send
each transmits in slot with probability p
probability of successful transmission S is:
by any specific single node: S= p (1-p)(N-1)
by any of N nodes
S = Prob (only one transmits)
= N p (1-p)(N-1)
for optimum p as N -> infty ...
= 1/e = .37
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