Evaluation of Adaptive Fuzzy Control Backoff Schemes in Policing Mechanisms

Fuzzy controllers are the most important applications of fuzzy theory, which provides an efficient method to handle inexact information as a basic of reasoning. Fuzzy logic converts knowledge which is expressed in an uncertain form to an exact algorithm. In fuzzy control, the controller can be represented by if-then-else rules. The controller is processing exact input data and is producing exact output data in a deterministic way. However, Backoff time computation schemes, namely: pseudorandom backoff (PB) time, exponential backoff (EB) time and random backoff (RB) time that are applicable in waiting time re-arrangement in queue. They have proved to be inefficient in coping with the conflicting requirements, that is, low dropping frames and high conforming frames. This led us to explore alternative solutions based on artificial intelligence techniques, specially, in the field of fuzzy logic. In this paper, we propose a fuzzy control backoff scheme that aims at detecting violations of parameter negotiated. We evaluate and compare the performance of fuzzy control backoff scheme (FB) with namely, pseudorandom backoff scheme (PB), random backoff scheme (RB) and exponential backoff scheme (EB). The performance of four backoff schemes have been investigated by the fluctuation of telecommunication traffic stream (burst/silent type). Simulation results show that the fuzzy control scheme helps improve performance of our re-arrangement waiting time in queue compared to other non-fuzzy backoff schemes. Moreover, RB is found to be better in bandwidth sensitive requirement but regardless to QoS