A three-dimensional probabilistic fuzzy control system for network queue management

A novel probabilistic fuzzy control system is proposed to treat the congestion avoidance problem in trans-mission control protocol(TCP) networks.Studies on traffic measurement of TCP networks have shown that the packet traffic exhibits long range dependent properties called self-similarity,which degrades the network performance greatly.The probabilistic fuzzy control(PFC) system is used to handle the complex stochastic features of self-similar traffic and the modeling uncertainties in the network system.A three-dimensional(3-D) membership function(MF) is embedded in the PFC to express and describe the stochastic feature of network traffic.The 3-D MF has extended the traditional fuzzy planar mapping and further provides a spatial mapping among "fuzziness-randomness-state".The additional stochastic expression of 3-D MF provides the PFC an additional freedom to handle the stochastic features of self-similar traffic.Simulation ex-periments show that the proposed control method achieves superior performance compared to traditional control schemes in a stochastic environment.