| A major challenge in mobile ad hoc networks is the design of routing protocols that are adaptive and scalable to network size, mobility and traffic loads. Traditional candidates are proactive, reactive and location-assisted (i.e., geographic) routing protocols such as
OLSR, AODV and GPSR. Their performance has been shown to vary quite significantly with network characteristics, and load conditions, thus making it impossible to name a winner for &096;&096;all conditions". In this study we focus on applications that stress mobility and sustained loads. Possible scenarios include, for example, search and rescue, urban homeland defense, small unit battlefield operations and car to car network games. We explore the scalability of the routing solutions to speed (up to vehicular ranges) and to load (e.g., data and multimedia file transfers and streams). Our approach is to seek hybrid solutions that combine attractive properties of previously proposed schemes. More specifically, we investigate a hybrid solution called AODV-DFR, an AODV protocol with Directional Forward Routing. AODV-DFR combines proactive and reactive routing
features. It also borrows from Geo-Routing the concept of greedy forwarding. This concept enables it to automatically find good candidates for packet forwarding in case of route breakage. Greedy forwarding here takes the form of &096;&096;directional forwarding". Each
node keeps a gradient direction toward the destination. This direction is dynamically refreshed based on periodic, proactive updates issued by the destination. Simulation studies show that AODV-DFR outperforms conventional protocols and even previous hybrid routing proposals across a wide range of network characteristics. |
| Jiwei Chen received the B.S. degree in applied mathematics and M.S. degree in automation from Nanjing University of Science and Technology, China. Currently, he is a Ph.D. candidate in Electrical Engineering of University of California, Los Angeles, where his research topics include protocol design, modeling and performance evaluation of transport, routing and MAC layers in ad hoc and heterogeneous networks. |