Mobile ad hoc networks consist of potentially moving, computing nodes that communicate via radio and do not have access to any fixed infrastructure. The knowl- edge about nearby nodes is a fundamental requirement and is part of many of the known solutions to problems in mobile and wireless networks including routing, broad- casting, distributed token circulation, etc. The existing solutions for this problem of knowing about neighbors are probabilistic. In this thesis, we give a first step towards a distributed, deterministic algorithm for finding out about the neighboring nodes. In particular, we focus on the problem of maintaining information about neighboring nodes in a one dimensional mobile and wireless ad hoc environment. Under some simplifying assumptions, we give an algorithm for the problem and a proof of correctness for the algorithm. We deal with efficiency in terms of both time and space. We prove a tight bound on the speed of propagation of the message when the nodes are sufficiently dense. We also consider the case when multiple clusters merge together. Our algorithm is space efficient in that the nodes do not include information about all the nodes they know in their broadcast message at all times. Nodes also store only the information about relevant nodes in their local store and purge information about nodes that have moved out of range. Our work shows that it is possible to solve the problem deterministically, and with reasonable values of the parameters, under some simplifying assumptions. Numerous interesting open questions remain in the area regarding how to relax the assumptions to make the approach more practical.

In the past decades, mobile traffic generated by devices such as smartphones, iphones, laptops and mobile gateways has been growing rapidly. While traditional direct connection techniques evolve to provide better access to the Internet, a new type of wireless network, mobile ad hoc network (MANET), has emerged. A MANET differs from a direct connection network in the way that it is multi-hopping and self-organizing and thus able to operate without the help of prefixed infrastructures. However, challenges such dynamic topology, unreliable wireless links and resource constraints impede the wide applications of MANETs. Routing in a MANET is complex because it has to react efficiently to unfavourable conditions and support traditional IP services. In addition, Quality of Service (QoS) provision is required to support the rapid growth of video in mobile traffic. As a consequence, tremendous efforts have been devoted to the design of QoS routing in MANETs, leading to the emergence of a number of QoS support techniques. However, the application independent nature of QoS routing protocols results in the absence of a one-for-all solution for MANETs. Meanwhile, the relative importance of QoS metrics in real applications is not considered in many studies. A Best Effort QoS support (BEQoS) routing model which evaluates and ranks alternative routing protocols by considering the relative importance of multiple QoS metrics is proposed in this thesis. BEQoS has two algorithms, SAW-AHP and FPP for different scenarios. The former is suitable for cases where uncertainty factors such as standard deviation can be neglected while the latter considers uncertainty of the problems. SAW-AHP is a combination of Simple Additive Weighting and Analytic Hierarchical Process in which the decision maker or network operator is firstly required to assign his/her preference of metrics with a specific number according to given rules. The comparison matrices are composed accordingly, based on which the synthetic weights for alternatives are gained. The one with the highest weight is the optimal protocol among all alternatives. The reliability and efficiency of SAW-AHP are validated through simulations. An integrated architecture, using evaluation results of SAW-AHP is proposed which incorporates the ad hoc technology into the existing WLAN and therefore provides a solution for the last mile access problems. The protocol selection induced cost and gains are also discussed. The thesis concludes by describing the potential application area of the proposed method. Fuzzy SAW-AHP is extended to accommodate the vagueness of the decision maker and complexity of problems such as standard deviation in simulations. The fuzzy triangular numbers are used to substitute the crisp numbers in comparison matrices in traditional AHP. Fuzzy Preference Programming (FPP) is employed to obtain the crisp synthetic weight for alternatives based on which they are ranked. The reliability and efficiency of SAW-FPP are demonstrated by simulations.

In crucial times, such as natural disasters like Earthquakes, Floods, military attack, rescue and emergency operations, etc., it is not possible to maintain an infrastructure. In these situations, wireless Mobile Ad-Hoc networks can be an alternative to wired networks. In our thesis, due to the importance of MANET (Mobile Ad-hoc Network) applications, we do research on MANET and its subtype IMANET (Internet based Mobile Ad-hoc Network). In MANETs, finding an optimum path among nodes is not a simple issue due to the random mobility of nodes and topology changes frequently. Simple routing algorithms like Shortest Path, Dijksta‟s and Link State fail to find route in such dynamic scenarios. A number of ad-hoc protocols (Proactive, Reactive, Hybrid and Position based) have been developed for MANETs. In this thesis, we have designed an IMANET in OPNET 14.5 and tested the performance of three different routing protocols namely OLSR (Optimum Link State Routing), TORA (Temporarily Ordered Routing Algorithm) and AODV (Ad-hoc On-demand Distance Vector) in different scenarios by varying the number of nodes and the size of the area. The experimental results demonstrate that among the three protocols, none of the routing protocol can ensure good quality HTTP and voice communication in all our considered scenarios.

A packet will be dropped when it arrives at a congested node in a routing path. The authors of [22] proposed the CRP protocol that can alleviate the congestion problem by splitting the traffic to the bypass nodes. In this thesis, we propose a new routing protocol, called MIMO-assisted congestion-adaptive routing protocol (MCRP for short), for multi-hop mobile ad hoc networks (MANETs for short). In MCRP, nodes periodically record the information of their rate-link/range-link neighbors. MCRP alleviates the congestion problem by dynamically adjusting the MIMO antenna mode and splitting the traffic to the downstream range-link neighbors. In addition, MCRP can quickly reestablish the routing path when it is broken due to node failure or mobility. Simulation results show that MCRP outperforms the existing protocols in terms of packet delivery ratio and end-to-end throughput.

Mobile ad hoc network is an architecture which do not exist any infrastructure or centralized administration. There are many routing protocols have been proposed so far, such as AODV, DSR and CGSR. These protocols were classified as reactive in which routes are established only when required. Due to the movement of mobile nodes, network topology changes frequently, and the routing path could be broken easily. This phenomenon will cause higher routing overhead and delivery latency. In conventional routing protocols, the source-destination pair only establishes a single path for data transmission. These routing scheme, however, suffer from the drawback of node movement. When route broken, the source node must reconstruct another new path. This paper presents an adaptive routing protocol named Adaptive Route Selection Scheme of Multiple Paths for Mobile Ad Hoc Network (ARSMA). The aim of the work is to improve the delivery ratio. In the route request phase, source nodes will discovery two routes to the destination node, one for primary path, and the other for the backup path. During the discovery procedure, each node will estimate the link expire time through the movement speed and direction of the precursor node. When a link breakage is about to occur, source node will try to switch the transmission to the backup route.The simulation result shows that ARSMA is able to achieve a remarkable improvement in delivery ratio and end-to-end dealy.

Mobile ad hoc networks are without centralized infrastructure, and suitable for the region that difficultly builds the basic network framework, for example, desert and ocean. The bandwidth in mobile ad hoc networks is likely to remain a scarce resource. A call request of a connection in a wireless network is blocked if there exits no bandwidth route. This blocking does not mean that the total system bandwidth capacity is less than the request, but that there is no path in which each link has enough residual unused bandwidth to satisfy the requirement. Like the routing in a datagram network, if packets of a virtual circuit can stream across multiple paths, we can select multiple bandwidth routes such that the total bandwidth can meet the requirement of a source-destination pair. Therefore, even though there is no feasible single path for a bandwidth-constrained connection, we may still have a chance to accept this one if we can find multiple bandwidth routes to meet the bandwidth constraint. In this dissertation, we propose a bandwidth-constrained routing algorithm to aggregate the bandwidth of multiple wireless links by splitting a data flow across multiple paths at the network layer. That is, it allows the packet flow of a source-destination pair to be delivered over multiple bandwidth routes with enough overall resources to satisfy a certain bandwidth requirement. Our algorithm considers not only the QoS requirement, but also the cost optimality of the routing paths to improve the overall network performance. Extensive simulations show that high call admission ratio and resource utilization are achieved with modest routing overheads. This algorithm can also tolerate the node moving, joining, and leaving. We also propose an algorithm, named efficient utilization polling (EUP), to support asynchronous data traffic at MAC layer by using the characteristics of Bluetooth technology. The algorithm uses a single bit in the payload header to carry the knowledge of queues in slaves for dynamically adapting the polling intervals for achieving the goals of high channel utilization and power conserving. In addition, we propose a differentiation mechanism, named shift-polling window (SPW). Based on EUP, the SPW differentiates the throughput from various classes, and still keeps the link utilization high and almost the same as that of the best-effort services. Extensive simulations are experimented on the behavior of the EUP and SPW by tuning the related parameters, such as polling interval, buffer size, and queue threshold level, etc., in order to verify the expectation of these methods.

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Mobile Ad hoc Network (MANET) routing protocols are designed to provide connectivity between wireless mobile nodes that do not have access to high-speed backbone networks. While many unicast MANET protocols have been explored, research involving multicast protocols has been limited. Existing multicast algorithms attempt to reduce routing overhead, but few, if any, attempt to reduce data overhead. The broadcast nature of wireless communication creates a unique environment in which overlaps in coverage are common. When designed properly, a multicast algorithm can take advantage of these overlaps and reduce data overhead. Unlike a unicast route, in which there is one path between a sender and receiver, a multicast tree can have multiple branches between the sender and its multiple receivers. Some of these paths can be combined to reduce redundant data rebroadcasts. The extensions presented in this thesis are a combination of existing and original routing techniques that were designed to reduce data rebroadcasts by aggregating multicast data flows. One such optimization takes advantage of the multipoint relay (MPR) nodes used by the Optimized Link State Routing (OLSR) unicast protocol. These nodes are used in unicast routing to reduce network broadcast, but can be used to help create efficient multicast data flows. Additionally, by listening to routing messages meant for other nodes, a host can learn a bit about its network and may be able to make routing changes that improve the multicast tree. This protocol was implemented as a software router in Linux. It should be emphasized that this is a real implementation and not a simulation. Experiments showed that the number of data packets in the network could be reduced by as much as 19 percent. These improvements were accomplished while using only a small amount of routing overhead. / Master of Science

A mobile ad hoc network (MANET) is formed by a collection of self-organizing nodes. Such networks are being deployed in a variety of environments, for example to provide mission-critical services in times of crises. Nodes participating in a MANET tend to have limited energy and computing resources and depend on various network-based resources to operate as a cohesive system. The same features such as dynamic and adaptive network topologies that make MANETs powerful also make the discovery and operation of network services a challenge. This thesis presents the design and implementation of an extensible information dissemination scheme that is integrated with the Optimized Link State Routing (OLSR) protocol to address the challenges of service discovery in mobile ad hoc networks. The thesis presents a detailed design of the information dissemination scheme based on the Naval Research Laboratory's (NRL) ProtoLib network protocol programming framework. In the proposed scheme, a solution that separates the routing process from the NRL OLSR routing protocol was designed, thus making OLSR a topology discovery protocol. This can further facilitate the implementation of various routing algorithms based on other metrics, such as the signal-to-noise ratio (SNR) of wireless links or the nodes' level of cooperation, when forwarding messages in the network. Additionally, a reusable event-driven programming interface to the NRL OLSR routing protocol was designed and implemented in this research. Events are triggered based on changes in the network topology. This programming interface can be used by other management and monitoring clients on the network for receiving real-time updates about link and topology changes as seen by OLSR. A priority message delivery scheme was developed that provides different quality of service (QoS) levels for information dissemination in mobile ad hoc networks. To ensure a fair use of the transport media and support various message sizes, a message fragmentation solution was implemented. The proposed information dissemination solution was then deployed in a real wireless ad-hoc environment for further validation and testing. Using experiments with six nodes and various test scenarios, this research verified the functionality and characterized the performance of the proposed system. It was observed that the link-state nature of information dissemination solution helped it to adapt to topology changes. It was also realized that service discovery latency after information convergence in the network was independent of the number of nodes between the service providers and clients. The experiments also confirmed that the immediate message delivery scheme provides superior quality of service to registered users in presence of radio interference and other delays caused by Multipoint Relay Nodes (MPR) message forwarding in OLSR. / Master of Science