Delay of the slotted ALOHA protocol with binary exponential backoff algorithm

Abstract

We propose a method to compute the delay of the slotted ALOHA protocol with Binary Exponential Backoff (BEB) as a collision resolution algorithm. When a message which tries to reserve a channel collides n times, it chooses one of the next 2(n) frames with equal probabilities and attempts the reservation again. We derive the expected access delay until an arbitrary message reserves a channel. Then the expected transmission delays for real time messages and non-real time messages are calculated analytically. The accuracy of our analytic model is checked against simulation.