A proposed fuzzy model for improving stability of multipath routing in MANETs / Hamdy Ahmed Mohamed `Sayedahmed` ; Supervised Hesham Ahmed Hefny , Imane Mohamed Amin-Fahmy

Thesis (M.Sc.) - Cairo University - Institute of Statistical Studies and Research - Department of Computer and Information Science

Mobile Ad Hoc Network is a type of wireless mobile networks in which there no previous infrastructure or centralized control existed. Today{u2019}s wide spread use of mobile devices such as: mobile phones, tablets, laptops and many others had driven the wireless Mobile Network growth especially the Mobile Ad hoc Networks commonly referred to as MANETs. MANET{u2019}s device is free to join or disjoin the network and free to move randomly. In addition, the devices are bounded of weight to be portable. These characteristicsturn to be a limitation for devices transmission ranges.Since the routing process is regarded as the core of communication and is associated with the network performance metrics, then its improvement will be revealed in the whole network performance improvement. Due to users{u2019} mobility, limited battery power, and limited transmission ranges, the current routing protocols should consider the stability of routes. Also, the lack of resources of MANETs may result in imprecise routing decisions. Dynamic Source Routing protocol (DSR) is a reactive routing protocol designated for MANET, whenever a route is demanded, DSR checks route cache for target destination, if no route exists; it floods the network with Route Request packets (RREQ). Route discovery process may result in multiple RREQ packets traversing the network until a Route Reply packet (RREP) is sent back.Therefore, reactive routing protocols increases routing overhead in route discovery process. However, the discovered route may contain nodes with no backup routes to the next hop or contain nodes with high mobility. Therefore, path failure may occur. In this research, a proposed fuzzy modelswere used to handle the imprecision of routing decisions by Fuzzy stability model for Dynamic Source Routing also referred as FSDSR1 and it had been tuned also referred as FSDSR2. Fuzzy models were tested and the derived results showed that, the first fuzzy model (FSMDSR1) outperformed the standard DSR in number of hops per route by 45%, formaximum route cache size by85%, for maximum total replies RREPs sent from destination by 86%, and for maximum wireless LAN delay by 89%. While the second fuzzy model (FSDSR2) outperformed FSDSR1 in route discovery time by 53% and the standard DSR by 44%, outperformed FSDSR1 in packet delivery ratio by 4% and the standard DSR by 10%, outperformed FSDSR1 in MANET delay by 4% and the standard DSR by 7%. Also, in some network densities FSMDSR2 had outperformed as FSMDSR1 or DSR

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