Prince Samar

Independent zone routing: an adaptive hybrid routing framework for ad hoc wireless networks

To effectively support communication in such a dynamic networking environment as the ad hoc networks, the routing framework has to be adaptable to the spatial and temporal changes in the characteristics of the network, such as traffic and mobility patterns. Multiscoping, as is provided through the concept of the Zone Routing Protocol (ZRP) for example, can serve as a basis for such an adaptive behavior. The Zone Routing framework implements hybrid routing by every network node proactively maintaining routing information about its local neighborhood called the routing zone, while reactively acquiring routes to destinations beyond the routing zone. In this paper, we propose the Independent Zone Routing (IZR) framework, an enhancement of the Zone Routing framework, which allows adaptive and distributed configuration for the optimal size of each nodes routing zone, on the per-node basis. We demonstrate that the performance of IZR is significantly improved by its ability to automatically and dynamically tune the network routing operation, so as to flexibly and robustly support changes in the network characteristics and operational conditions. As a point of reference, through this form of adaptation, we show that the volume of routing control traffic overhead in the network can be reduced by an order of magnitude, under some set of parameter values. Furthermore, the adaptive nature of IZR enhances the scalability of these networks as well.

On the behavior of communication links of a node in a multi-hop mobile environment

In this work, we develop an analytical framework to investigate the behavior of the communication links of a node in a random mobility environment. Analytical expressions characterizing various properties related to the formation, lifetime and expiration of links are derived. The derived framework can be used to design efficient algorithms for medium access, routing and transport control, or to analyze and optimize the performance of existing network protocols. A number of applications of the characteristics investigated, such as selection of stable routes, route cache lifetime optimization, providing Quality-of-Service (QoS) data communication and analysis of route lifetime are discussed. In particular, we focus on designing an efficient updating strategy for proactive routing protocols based on the derived statistics. Using simulations, we show that the proposed strategy can lead to significant performance improvements in terms of reduction in routing overhead, while maintaining high data packet delivery ratio and acceptable latency.

Link Dynamics and Protocol Design in a Multihop Mobile Environment

A multihop ad hoc network with mobile elements is considered. A model is created and analytic expressions derived to characterize the statistics for link lifetime, new link interarrival time, link breakage interarrival time, and link change interarrival time. Applications of these expressions to protocol design are discussed. As an example application, the link model is used to find an optimal balance between reactive and proactive routing strategies. It is shown that, when control traffic generated through proactive route updating is matched to link lifetimes, control traffic is significantly reduced while the goodput and delay benefits of the proactive approach are retained

Hybrid routing: the pursuit of an adaptable and scalable routing framework for ad hoc networks

Advances in ad hoc network research have opened the door to an assortment of promising military and commercial applications for ad hoc networks. However, because each application has unique characteristics (such as traffic behavior, device capabilities, mobility patterns, operating environments, etc.), routing in such a versatile environment is a challenging task, and numerous protocols have been developed to address it. While many protocols excel for certain types of ad hoc networks, it is clear that a single basic protocol cannot perform well over the entire space of ad hoc networks. To conform to any arbitrary ad hoc network, the basic protocols designed for the edges of the ad hoc network design space need to be integrated into a tunable framework.The Zone Routing framework demonstrates how multi-scoping can provide the basis for a hybrid routing protocol framework. Zone Routing proactively maintains routing information for a local neighborhood called the routing zone (local scope), while reactively acquiring routes to destinations beyond the routing zone. In this paper, we review the Zone Routing concept and propose Zone Routing with independently sized routing zones capability. With this capability, each of the nodes in the network can adaptively configure its own optimal zone radius in a distributed fashion. We show that the performance of Zone Routing is significantly improved by the ability to provide fine-tuned adaptation to local and temporal variations in network characteristics.

Strategies for broadcasting updates by proactive routing protocols in mobile ad hoc networks

Proactive routing protocols for mobile ad hoc networks are table-driven, where each node tries to maintain routing information about every other node in the network at all times. Mobility of the nodes in the network causes creation of new links or breaking of old links, changing network routes dynamically. These changes require a proactive routing protocol to regularly broadcast updates in the network to enable other nodes to maintain correct routing information. The performance of a proactive protocol depends on the particular strategy the protocol uses to broadcast these updates. The updating strategies used by the current proactive protocols to broadcast detected link changes in the network are found to be inefficient. We propose three new strategies for broadcasting proactive updates in the network. Analysis of these updating schemes using simulations shows that the proposed schemes lead to significant savings in the amount of routing control traffic generated in the network. At the same time, the performance of these schemes is satisfactory in terms of the data throughput, route success rate, etc. For example, for a moderately sized network, simulation results show that the proposed schemes can lead to more than 45% savings in terms of routing control traffic, while maintaining decent performance of the network.