Type-2 fuzzy decision support system to optimise MANET integration into infrastructure-based wireless systems

Mobile ad hoc networks are able to extend the coverage area of Internet access points by establishing multihop communication paths. Due to diverse factors such as the mobility of the nodes, the propagation conditions or the traffic status, the communication paths present a lifetime. In fact, the quality of the Internet connection mainly depends on the durability of the employed communication routes. In order to improve the network performance, the nodes should select the best route in terms of its remaining lifetime. Since the factors impacting the route lifetime are unpredictable, the route remaining lifetime cannot be analytically derived. Under these circumstances, a fuzzy-logic system outstands as a potential solution to estimate the stability of the routes. This paper analyses the potentiality of this kind of solution. In particular, the paper presents a fuzzy logic system which should be installed in the mobile nodes to distributedly identify the stable routes. In particular, the system is supported by an interval-based type-2 fuzzy logic. Being a type-2 fuzzy logic system, it is able to cope with inexact estimations. This ability is necessary to avoid the use of additional messages which will occupy the scarce wireless medium. On the other hand, an interval-based fuzzy system provides the simplicity demanded by the energy-constrained mobile devices. As a novelty, the two outputs of the interval-based fuzzy system are employed. The use of each output depends on the traffic state of the mobile node. By means of extensive simulations, we demonstrate the goodness of the proposed system.