Maritime network plays an important role in civilian and academic applications. However, traditional maritime communication technologies cannot provide broadband services that can satisfy users' need. In this thesis, we proposed a buoy-based maritime mesh network and analyzed the maritime communication characteristics. Then we proposed a link-state-aware routing protocol to address link blockage problem when routing packets and built a simulator to evaluate the network performance. There are several parts of my work. Firstly, we simulated ocean water field. Jerry Tessendorf proposed a method to create ocean surface based on Phillips spectrum which is a wind-driven, semi-empirical oceanography model. We implemented this algorithm in MATLAB and adjusted a key parameter in this algorithm. Secondly, we proposed a link-state-aware routing protocol. Link stability is related to sea state and instant nodes elevation. In link-state-aware routing protocol, the transmitter will send predicted elevation information to receiver, and receiver will decide if the link is stable in next several seconds based on sea states and node elevation information. Finally, we simulated this mesh network in network simulator 3 (NS3). This simulator will enable users to assess the network performance in various sea states. We also need to build a new mobility model, a new propagation model and implement a collision-free access method (spatial TDMA) model in simulation. / Master of Science / Due to burst growth of network coverage, seamless broadband connectivity has been realized in both our daily life and industrial operations. However, wireless communication coverage fades away when moving just several miles away from the coast. Current marine communication technologies cannot provide stable and broadband service, so we proposed a buoy-based maritime mesh network. In this thesis, we built a network simulator which integrates with several new models after analyzed the dynamic ocean wave motion and maritime communication link characteristics.

Prior research in routing for wireless ad hoc networks has shown that multipath routing can enhance data delivery reliability and provide load balancing. Nevertheless, only a few multipath routing algorithms have been proposed and their interaction with transport layer protocols has not been thoroughly addressed in the literature. In this work, we propose the multipath “Fresnel zone” routing (FZR) algorithm for wireless ad hoc networks. FZR constructs multiple parallel paths from source to destination based on the concept of “Fresnel zones” in a wireless network. The zone construction method assigns intermediate routers into different “Fresnel zones” according to their capacity and efficiency in forwarding traffic. The central idea in FZR is to disperse traffic to different zones according to network load and congestion conditions, thus achieving better throughput and avoiding congestion at intermediate routers. FZR differs from most existing multipath routing approaches in that both source and intermediate nodes use multiple forwarding paths. FZR also adopts a combination of proactive and on-demand (reactive) approaches to reduce control overhead and latency for packet delivery. Simulation experiments have shown that FZR outperforms unipath distance vector routing, multipath distance vector (MDV) routing, and split multipath routing (SMR) algorithms in quasistatic wireless ad hoc networks. In our simulations, FZR achieves up to 100 percent higher average throughput using the User Datagram Protocol (UDP) and 50 percent higher average throughput using the Transmission Control Protocol (TCP). FZR can also provide better load balancing among different paths, improve network resource utilization, and enable fairer resource allocation among different data transmission sessions. Future work is needed to evaluate FZR in mobile scenarios. / Master of Science

Mobile Ad hoc Networks (MANETs) are re-emerging as a popular networking facility for wireless device users. A growing number of diversified applications are now accessible via wireless devices. The different applications may have different Quality of Service (QoS) requirements, which may better be satisfied by using different routing methods or metric types. Existing ad hoc network routing solutions do not consider various application-level requirements when making a routing decision. They typically make routing decisions based upon limited information acquired at the network layer. Most of the existing routing protocols make use of a single routing metric. Using a single metric type and/or information, only acquired at the network layer may not be able to accommodate different QoS requirements, imposed by diversified user-level applications or application-level data types.The aim of this thesis is to design an efficient routing function for ad hoc networks while at the same time satisfying users‟ and/or applications‟ QoS and security requirements. To achieve this, the thesis investigates and specifies routing requirements that could best support application-level QoS and security requirements in MANETs. It also investigates and critically analyses the state of the art in MANET routing, and the mechanisms used for protecting the routing functions. To overcome the weaknesses and advance the state of the art in MANET routing, this thesis proposes two major solutions. The first solution is the Secure ETX (SETX) routing protocol. It is a secure routing solution that can provide routing functions efficiently in malicious MANET environment. The SETX protocol provides a security mechanism to counter black hole attacks in MANETs on the ETX metric acquisition process. Simulation studies have been carried out and discussed in the thesis. Simulation results show that the SETX protocol can provide a marked improvement in network performances in the presence of black hole attacks, and it can do so with a negligible level of additional overhead.The second solution is a novel routing decision making called the Flexible Routing Decision (FRD) framework. The FRD framework supports routing decision making by using multiple metric types (i.e. multi-criteria routing decision making) and uses a cross-layer approach to support application-level QoS requirements. This allows users to use different routing metrics types, making the most appropriate routing decision for a given application. To accommodate the diversified application-level QoS requirements, multiple routing metric types have been identified and interpreted in the FRD framework design. The FRD framework has overcome some weaknesses exhibited by existing single metric routing decision making, used in MANETs. The performance of a routing decision making of FRD is also evaluated using NS2 simulation package. Simulation results demonstrate that the FRD framework outperforms the existing routing decision making methods.

ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / An ad hoc network is a group of wireless nodes which do not rely on any fixed infrastructure. Hosts cooperate by forwarding packets for each other to communicate with nodes that are out of the radio transmission range. We propose a new routing algorithm that is based on the concept of multipoint relay nodes (MPR). The main focus of the Trust Level Routing protocol is the reliability and survivability of the network by applying costs to each MPR candidate. The cost calculation is based on the delay incurred, energy available at the MPR node, energy spent during transmission and number of packets sent on each link. We highlight the vulnerabilities in current link state routing algorithms and propose the use of light weight encryption algorithms to achieve a dependable routing algorithm. Network simulator (ns-2) is used to compare the protocol performance to other existing link state routing protocols.

Mobile Delay Tolerant Networks (MDTNs) are wireless mobile networks in which a complete routing path between two nodes that wish to communicate cannot be guaranteed. A number of networking scenarios have been categorized as MDTNs, such as vehicular ad hoc networks, pocket switched networks, etc. The network asynchrony, coupled with the limited resources of mobile devices make message dissemination (also called routing) one of the fundamental challenges in MDTNs. In the literature, a large body of work has been done to deal with routing in MDTNs. However, most of the existing routing protocols are based on at least one of the following three assumptions: (1) all messages can be routed by relying on a single mobility property; (2) all messages can be routed using a single message allocation strategy; (3) users are willing to disclose their mobility information and relationships to others in order to improve the quality of the routing. We argue that the above three assumptions are not realistic because: (1) users can exhibit various social behaviors and consequently various mobility properties (e.g., they can have regular movements during week-days and exhibit non-predictable movements during week-ends); (2) some messages might need more or less copies to be delivered according to the localization of the source and the destination and to the urgency of the message; and (3) users mobility data can disclose sensitive information about the users. In this thesis, we relieve MDTN routing from the above three restrictive assumptions. Firstly, we propose an adaptive routing protocol for mobile delay tolerant networks. The proposed protocol can dynamically learn the social properties of nodes based on their mobility patterns, and exploit the most appropriate routing strategy each time an intermediate node is encountered. Simulations performed on real mobility traces show that our protocol achieves a better delivery ratio than existing state-of-the-art routing protocols that rely on a single mobility property. Secondly, we present a delay and cost balancing protocol for efficient routing in mobile delay tolerant networks. The presented protocol reasons on the remaining time-to-live of a message to dynamically allocate the minimum number of copies that are necessary to achieve a given delivery probability. Evaluation results show that the protocol can achieve a good balance between message delivery delay and delivery cost, compared with most of the existing routing protocols in the literature. Lastly, we propose an efficient privacy preserving prediction-based routing protocol for mobile delay tolerant networks. This protocol preserves the mobility patterns of a node from being disclosed by exploiting the mobility pattern of communities that node belongs to. Evaluation results demonstrate that this protocol can obtain comparable routing performance to prediction-based protocols while preserving the mobility pattern of nodes.

Wireless Sensor Networks (WSNs) have significant potential in many application domains, and are poised for growth in many markets ranging from agriculture and animal welfare to home and office automation. Although sensor network deployments have only begun to appear, the industry still awaits the maturing of this technology to realize its full benefits. The main constraints to large scale commercial adoption of sensor networks are the lack of available network management and control tools for determining the degree of data aggregation prior to transforming it into useful information, localizing the sensors accurately so that timely emergency actions can be taken at exact location, and scheduling data packets so that data are sent based on their priority and fairness. Moreover, due to the limited communication range of sensors, a large geographical area cannot be covered, which limits sensors application domain. Thus, we investigate a scalable and flexible WSN architecture that relies on multi-modal nodes equipped with IEEE 802.15.4 and IEEE 802.11 in order to use a Wi-Fi overlay as a seamless gateway to the Internet through WiMAX networks. We focus on network management approaches such as sensors localization, data scheduling, routing, and data aggregation for the WSN plane of this large scale multimodal network architecture and find that most existing approaches are not scalable, energy efficient, and fault tolerant. Thus, we introduce an efficient approach for each of localization, data scheduling, routing, and data aggregation; and compare the performance of proposed approaches with existing ones in terms of network energy consumptions, localization error, end-to-end data transmission delay and packet delivery ratio. Simulation results, theoretical and statistical analysis show that each of these approaches outperforms the existing approaches. To the best of our knowledge, no integrated network management solution comprising efficient localization, data scheduling, routing, and data aggregation approaches exists in the literature for a large scale WSN. Hence, we e±ciently integrate all network management components so that it can be used as a single network management solution for a large scale WSN, perform experimentations to evaluate the performance of the proposed framework, and validate the results through statistical analysis. Experimental results show that our proposed framework outperforms existing approaches in terms of localization energy consumptions, localization accuracy, network energy consumptions and end-to-end data transmission delay.

Wireless sensor networks (WSNs), being a relatively new technology, largely employ protocols designed for other ad hoc networks, especially mobile ad hoc networks (MANETs). However, on the basis of applications, there are many differences between WSNs and other types of ad hoc network and so WSNs would benefit from protocols which take into account their specific properties, especially in routing. Bhatti and Yue (2006) proposed an addressing scheme for multi-hop networks. It provides a systematic address structure for WSNs and allows network topology to avoid the fatal node failure problem which could occur with the ZigBee tree structure. In this work, a new routing strategy is developed based on Bhatti and Yue’s addressing scheme. The new approach is to implement a hybrid flooding scheme that combines flooding with shortest-path methods to yield a more practical routing protocol for static WSN applications. The primary idea is to set a flooding counter K as an overhead parameter of control messages which are used to discover routes between any arbitrary nodes. These route request messages are flooded for K hops and then oriented by shortest-path routing from multiple nodes in the edge of the flooding area to the destination. The simulation results show that this protocol under certain wireless circumstances is more energy conscious and produces less redundancy than reactive ZigBee routing protocol. Another advantage is that the routing protocol can adapt any dynamic environment in various WSN applications to achieve a satisfactory data delivery ratio in exchange for redundancy.

Uma Rede Móvel Ad Hoc (MANET) consiste em uma coleção de terminais que possuem uma interface de transmissão e recepção sem fio (wireless) e que se movimentam em uma determinada área de abrangência. Geralmente esses terminais fazem uso de freqüências de rádio nas comunicações e configuram uma rede não infraestruturada. As MANETs, também conhecidas como independentes, não necessitam de qualquer infra-estrutura pré-existente para prover comunicação entre os nós, contudo, são utilizadas, principalmente quando integradas à Internet. Essa integração, apesar de possível, normalmente necessita de um gateway que encaminhe os pacotes entre as redes de computadores, respeitando as suas características individuais. Problemas, assim como atrasos e perdas de pacotes, podem ser provocados pelas diferenças intríncias aos protocolos de roteamento. Embora o Internet Engineering Task Force (IETF) proponha diversos protocolos de roteamento para as MANETs, o presente trabalho investiga o protocolo de roteamento Ad hoc On-Demand Distance Vector (AODV), por ser considerado um dos protocolos mais implementados e estudados pelo grupo de trabalho do IETF. O nodo gateway, embora já esteja implementado no protocolo de roteamento AODV (HAMIDIAN, 2003), deve ser capaz de interagir com as funções de roteamento da Internet, trocando tráfego com a mesma, de modo transparente e eficiente. O protocolo AODV, por ser reativo, pode demorar até 0,05 segundos para estabelecer uma rota entre um nodo origem e um nodo destino. Nos padrões atuais esse tempo pode ser considerado exageradamente alto, gerando gargalos entre sub-redes, descarte de pacotes e baixa eficiência. O presente trabalho apresenta uma proposta de customização do protocolo de roteamento AODV com atuação restrita ao nodo gateway. Esta customização consiste na adição de uma métrica de confiabilidade no processo de descoberta e utilização de rotas visando a redução no número de pacotes descartados e um ganho de eficiência no fluxo de dados entre as sub-redes envolvidas. / A Mobile Ad Hoc Network (MANET) consists of a collection of mobile hosts, moving in certain range area, that has a wireless interface for transmission and receiving data. Usually these terminals make use of radio frequencies in communications and configure a non infrastructured network. The MANETs, also known as independent, require no pre-existing infrastructure to provide communication between network mobile nodes, however, are used, preferably when integrated with the Internet. This integration, although possible, usually need a gateway that forwards packets between both computer networks, keeping their individual characteristics. Problems such as delays and packet losses can be caused by differences inherent in the routing protocols. Although the Internet Engineering Task Force (IETF) proposes several routing protocols for MANETs, this paper investigates the Ad hoc On-Demand Distance Vector (AODV) routing protocol, viewed as one of more implemented and studied protocol by the IETF work group. The gateway node, which is already implemented in the AODV routing protocol (Hamidian, 2003), should be able to interact, transparently and efficiently, with the Internet routing functions exchanging traffic between them. The AODV protocol, being reactive, can take up to 0.05 seconds to establish a route between a source node and a destination node. By today's standards this time may be considered excessively high, creating bottlenecks between subnets, packet drop and low efficiency. This paper proposes an AODV routing protocol customization restricted to the gateway node activities. This customization consists of adding reliability metric in the route discovery process and its consequent use in order to reduce the number of dropped packets and get increased efficiency in the data flow between the subnets involved.

Uma Rede Móvel Ad Hoc (MANET) consiste em uma coleção de terminais que possuem uma interface de transmissão e recepção sem fio (wireless) e que se movimentam em uma determinada área de abrangência. Geralmente esses terminais fazem uso de freqüências de rádio nas comunicações e configuram uma rede não infraestruturada. As MANETs, também conhecidas como independentes, não necessitam de qualquer infra-estrutura pré-existente para prover comunicação entre os nós, contudo, são utilizadas, principalmente quando integradas à Internet. Essa integração, apesar de possível, normalmente necessita de um gateway que encaminhe os pacotes entre as redes de computadores, respeitando as suas características individuais. Problemas, assim como atrasos e perdas de pacotes, podem ser provocados pelas diferenças intríncias aos protocolos de roteamento. Embora o Internet Engineering Task Force (IETF) proponha diversos protocolos de roteamento para as MANETs, o presente trabalho investiga o protocolo de roteamento Ad hoc On-Demand Distance Vector (AODV), por ser considerado um dos protocolos mais implementados e estudados pelo grupo de trabalho do IETF. O nodo gateway, embora já esteja implementado no protocolo de roteamento AODV (HAMIDIAN, 2003), deve ser capaz de interagir com as funções de roteamento da Internet, trocando tráfego com a mesma, de modo transparente e eficiente. O protocolo AODV, por ser reativo, pode demorar até 0,05 segundos para estabelecer uma rota entre um nodo origem e um nodo destino. Nos padrões atuais esse tempo pode ser considerado exageradamente alto, gerando gargalos entre sub-redes, descarte de pacotes e baixa eficiência. O presente trabalho apresenta uma proposta de customização do protocolo de roteamento AODV com atuação restrita ao nodo gateway. Esta customização consiste na adição de uma métrica de confiabilidade no processo de descoberta e utilização de rotas visando a redução no número de pacotes descartados e um ganho de eficiência no fluxo de dados entre as sub-redes envolvidas. / A Mobile Ad Hoc Network (MANET) consists of a collection of mobile hosts, moving in certain range area, that has a wireless interface for transmission and receiving data. Usually these terminals make use of radio frequencies in communications and configure a non infrastructured network. The MANETs, also known as independent, require no pre-existing infrastructure to provide communication between network mobile nodes, however, are used, preferably when integrated with the Internet. This integration, although possible, usually need a gateway that forwards packets between both computer networks, keeping their individual characteristics. Problems such as delays and packet losses can be caused by differences inherent in the routing protocols. Although the Internet Engineering Task Force (IETF) proposes several routing protocols for MANETs, this paper investigates the Ad hoc On-Demand Distance Vector (AODV) routing protocol, viewed as one of more implemented and studied protocol by the IETF work group. The gateway node, which is already implemented in the AODV routing protocol (Hamidian, 2003), should be able to interact, transparently and efficiently, with the Internet routing functions exchanging traffic between them. The AODV protocol, being reactive, can take up to 0.05 seconds to establish a route between a source node and a destination node. By today's standards this time may be considered excessively high, creating bottlenecks between subnets, packet drop and low efficiency. This paper proposes an AODV routing protocol customization restricted to the gateway node activities. This customization consists of adding reliability metric in the route discovery process and its consequent use in order to reduce the number of dropped packets and get increased efficiency in the data flow between the subnets involved.

Uma Rede Móvel Ad Hoc (MANET) consiste em uma coleção de terminais que possuem uma interface de transmissão e recepção sem fio (wireless) e que se movimentam em uma determinada área de abrangência. Geralmente esses terminais fazem uso de freqüências de rádio nas comunicações e configuram uma rede não infraestruturada. As MANETs, também conhecidas como independentes, não necessitam de qualquer infra-estrutura pré-existente para prover comunicação entre os nós, contudo, são utilizadas, principalmente quando integradas à Internet. Essa integração, apesar de possível, normalmente necessita de um gateway que encaminhe os pacotes entre as redes de computadores, respeitando as suas características individuais. Problemas, assim como atrasos e perdas de pacotes, podem ser provocados pelas diferenças intríncias aos protocolos de roteamento. Embora o Internet Engineering Task Force (IETF) proponha diversos protocolos de roteamento para as MANETs, o presente trabalho investiga o protocolo de roteamento Ad hoc On-Demand Distance Vector (AODV), por ser considerado um dos protocolos mais implementados e estudados pelo grupo de trabalho do IETF. O nodo gateway, embora já esteja implementado no protocolo de roteamento AODV (HAMIDIAN, 2003), deve ser capaz de interagir com as funções de roteamento da Internet, trocando tráfego com a mesma, de modo transparente e eficiente. O protocolo AODV, por ser reativo, pode demorar até 0,05 segundos para estabelecer uma rota entre um nodo origem e um nodo destino. Nos padrões atuais esse tempo pode ser considerado exageradamente alto, gerando gargalos entre sub-redes, descarte de pacotes e baixa eficiência. O presente trabalho apresenta uma proposta de customização do protocolo de roteamento AODV com atuação restrita ao nodo gateway. Esta customização consiste na adição de uma métrica de confiabilidade no processo de descoberta e utilização de rotas visando a redução no número de pacotes descartados e um ganho de eficiência no fluxo de dados entre as sub-redes envolvidas. / A Mobile Ad Hoc Network (MANET) consists of a collection of mobile hosts, moving in certain range area, that has a wireless interface for transmission and receiving data. Usually these terminals make use of radio frequencies in communications and configure a non infrastructured network. The MANETs, also known as independent, require no pre-existing infrastructure to provide communication between network mobile nodes, however, are used, preferably when integrated with the Internet. This integration, although possible, usually need a gateway that forwards packets between both computer networks, keeping their individual characteristics. Problems such as delays and packet losses can be caused by differences inherent in the routing protocols. Although the Internet Engineering Task Force (IETF) proposes several routing protocols for MANETs, this paper investigates the Ad hoc On-Demand Distance Vector (AODV) routing protocol, viewed as one of more implemented and studied protocol by the IETF work group. The gateway node, which is already implemented in the AODV routing protocol (Hamidian, 2003), should be able to interact, transparently and efficiently, with the Internet routing functions exchanging traffic between them. The AODV protocol, being reactive, can take up to 0.05 seconds to establish a route between a source node and a destination node. By today's standards this time may be considered excessively high, creating bottlenecks between subnets, packet drop and low efficiency. This paper proposes an AODV routing protocol customization restricted to the gateway node activities. This customization consists of adding reliability metric in the route discovery process and its consequent use in order to reduce the number of dropped packets and get increased efficiency in the data flow between the subnets involved.