Opportunistic Routing (OR) is an effective and enhanced routing scheme for wireless multihop environment. OR is an approach that selects a certain number of best forwarders (candidates) at each hop by taking the advantage of the broadcast nature of the wireless medium to reach the destination. When a set of candidates receive the packet, they coordinate with each other to figure out which one has to forward the packet toward the destination. Most of the research in this area has been done in mesh networks where nodes do not have mobility. In this survey, we propose a new OR protocol for mobile ad hoc scenarios called as Enhanced Mobility-based Opportunistic Routing (EMOR) protocol. To deal with the node mobility, we have proposed a new metric which considers the following: geographical position of the candidates; the link delivery probability to reach them; the number of neighboring nodes of candidates; and the predicted position of nodes using the motion vector of the nodes. We have compared EMOR with five other well-known routing protocols in terms of delivery ratio, end-to-end delay, and expected number of transmissions from source to the destination. Our simulation results show that proposed protocol improves delivery ratio and number of expected transmission in terms of different type of mobility models.

In future, Mobile Ad Hoc Networks (MANETs) may provide access to services in the Internet. MANETs should therefore support diverse applications and data types. This introduces a need for quality of service (QoS), a process of discriminating different data types to provide them with an appropriate level of service. However, QoS can be affected by nodes performing packet forwarding attacks. A critical analysis of the related literature shows that research into QoS and security has typically proceeded independently. However, QoS and security should be considered together as attacks may adversely affect QoS. A simulation study demonstrates this by investigating two single-path packet forwarding approaches under a range of conditions. The study shows that using single-path packet forwarding in the presence of attackers is generally insufficient to support QoS.Based on this background research, a novel 2-Dimensional Adaptation ARChitecture (2-DAARC) and a Priority-based Multi-path Type Selection (PMTS) algorithm are proposed. 2-DAARC integrates two modes of adaptation. The single-path adaptation (SPA) mode uses adaptive bandwidth reservations over a single path for QoS in the presence of node mobility. The multi-path adaptation (MPA) mode uses duplicated data packet transmissions over multiple paths for QoS in the presence of packet forwarding attackers. Adaptation occurs within and between modes to optimize priority packet forwarding in the dynamic MANET environment. The MPA mode uses the PMTS algorithm to select a secondary path which is maximally-disjoint with the primary path. This aims to select a path which may enhance reliability whilst keeping the costs of path selection low. Simulating 2-DAARC shows that under light loads it achieves better QoS than related work, but with a higher control packet overhead. Simulating PMTS shows that under light loads it achieves packet deliveries which are at best as good as a related approach, with lower end-to-end delays and control packet overhead. A novel Congestion and ATtack (CAT) detection mechanism is proposed to improve the performance of 2-DAARC in heavily loaded networks. CAT detection differentiates the causes of packet loss so that adaptation can be better tailored to the network conditions. Without CAT detection, 2-DAARC uses the MPA mode in congested conditions, and this worsens QoS. Simulating 2-DAARC with CAT detection shows that it generally achieves packet deliveries which are greater than or similar to, and end-to-end delays which are less than or similar to related work, and it does so with a lower control packet overhead.

Although smart mobile devices have only come into prominence recently, they have quickly become a necessity in the modern world. In 2012, more than 450 million new smartphones are expected to be purchased around the world, exceeding, for the first time, purchases of laptops and desktop PCs combined in a single year. That, in addition to the increasing processing power and low cost of these emerging mobile devices, creates an increasing demand for mobile applications that work in infrastructure-supported environments like WiFi and cellular networks as well as infrastructure-less environments like ad hoc networks. Therefore, the behavior of mobile devices in such scenarios should be a continued focus of research. Several factors contribute to the observed behavior of nodes in Mobile Ad-hoc Networks MANETs. For example, nodes may act selfishly to preserve their limited energy resources. This selfishness may be detrimental to network performance. Therefore, cooperation between peers is necessary to keep these MANETs operational. Beside the need for actively encouraging cooperation by providing incentives, passive encouragement is also needed to overcome the effect of factors that limit cooperation, including malicious behavior, environmental obstruction, and mobility. The contribution of this work is to provide a cooperation model in MANETs that is capable of surviving topology distortions caused by mobility, and is operable in practical distributed scenarios. Towards this goal, we first provide a study of the topology characteristics of MANETs based on real experiments. We study the node degree, link stability, and link symmetry of these networks, and, based on our observations, we suggest a two-state Markov model to model link state in such networks, demonstrating the superiority of this model over the widely-used disk model with mobility. We conclude from this study that both mobility and channel fluctuations have a significant influence on the network topology, which makes it important to study cooperation in scenarios where the topology is changing rapidly. Based on experimental observations of a real network, we propose a coalition game model for cooperation in MANETs that shows that stable, effective coalitions can be maintained, even in the face of a dynamic network topology. We provide an initial evaluation of the model using a centralized simulation approach. We use the notion of reachability to evaluate the proposed model, and we simulate the model under different speeds and node densities. Our simulations show that reachability can be sustained at stable levels despite the deterioration caused by mobility. In addition, we show that our cumulative coalition formation approach gives good results in terms of reachability level and computational complexity. We also show that our proposed model achieves a fair payoff distribution among participating nodes. Motivated by the promising results of our centralized simulation approach, we take a further step towards more practical evaluation. We integrate the cooperation model with an existing MANET routing protocol, OLSR, and evaluate it in this distributed environment. We modify and augment the OLSR messaging mechanism to enable the exchange of the coalition information required to keep the model operating. Beside ensuring that the reachability gain is still attained and the coalition structure is stable, we study the effect of the extra control traffic overhead incurred by the model. We compare deliverability over the network with and without the cooperation model. Although our results show that the cooperation model incurs an average overhead exceeding $100\%$ of that incurred by OLSR in high density scenarios, it shows better reliability in delivering traffic especially among selfish nodes in low and average density scenarios. Counter to what is commonly assumed in the literature, this study shows that cooperation can be be maintained in a distributed manner without causing significant traffic overhead to MANETs run by proactive routing protocols. Due to the simplicity, several extensions can be applied to enhance the performance of the proposed model and diversify its usage. We propose these extensions at the end of this dissertation. / Ph. D.

No description available.

No description available.

This thesis describes the Flexible Internetwork Stack (FINS) Framework, an open-source tool to facilitate experimental research in wireless networks on multiple platforms. The FINS Framework uses a module-based architecture that allows cross-layer behavior and runtime reconfiguration of the protocol stack. Version 1.0 of the framework makes use of existing physical and data link layer functionality, while enabling modifications to the stack at the network layer and above, or even the implementation of a clean-slate, non-layered protocol architecture. Protocols, stubs for communicating with intact layers, and management and supervisory functions are implemented as FINS Framework modules, interconnected by a central switch. This thesis describes the FINS Framework architecture, presents an initial assessment along with experiments on Android and Ubuntu enabled by the tool, and documents an intuitive mechanism for transparently intercepting socket calls that maintains efficiency and flexibility. / Master of Science

Esta tesis nos ha permitido trasladar algunos conceptos teóricos de la computación ubicua a escenarios reales, identificando las necesidades específicas de diferentes tipos de aplicaciones. Con el fin de alcanzar este objetivo, proponemos dos prototipos que proporcionan servicios sensibles al contexto en diferentes entornos, tales como conferencias o salas de recuperación en hospitales. Estos prototipos experimentales explotan la tecnología Bluetooth para ofrecer información basada en las preferencias del usuario. En ambos casos, hemos llevado a cabo algunos experimentos con el fin de evaluar el comportamiento de los sistemas y su rendimento. También abordamos en esta tesis el problema de la autoconfiguración de redes MANET basadas en el estándar 802.11 a través de dos soluciones novedosas. La primera es una solución centralizada que se basa en la tecnología Bluetooth, mientras la segunda es una solución distribuida que no necesita recurrir a ninguna tecnología adicional, ya que se basa en el uso del parámetro SSID. Ambos métodos se han diseñado para permitir que usuarios no expertos puedan unirse a una red MANET de forma transparente, proporcionando una configuración automática, rápida, y fiable de los terminales. Los resultados experimentales en implementaciones reales nos han permitido evaluar el rendimiento de las soluciones propuestas y demostrar que las estaciones cercanas se pueden configurar en pocos segundos. Además, hemos comparado ambas soluciones entre sí para poner de manifiesto las diferentes ventajas y desventajas en cuanto a rendimento. La principal contribución de esta tesis es EasyMANET, una plataforma ampliable y configurable cuyo objetivo es automatizar lo máximo posible las tareas que afectan a la configuración y puesta en marcha de redes MANET, de modo que su uso sea más simple y accesible. / Cano Reyes, J. (2012). Integrated Architecture for Configuration and Service Management in MANET Environments [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/14675

In this thesis, we are concerned with content dissemination in mobile ad hoc networks. The scope of content dissemination is limited by network capacity, and sometimes the price to be paid for securing faster delivery. In the first part of the thesis, we address the issue of finding the maximum throughput that a mobile ad-hoc network can support. We have assumed that there is no price involved, and all nodes work as a team. The problem of determining the capacity region has long been known to be NP-hard even for stationary nodes. Mobility introduces an additional dimension of complexity because nodes now also have to decide when they should initiate route discovery. Since route discovery involves communication and computation overhead, it should not be invoked very often. On the other hand, mobility implies that routes are bound to become stale, resulting in sub-optimal performance if routes are not updated. We attempt to gain some understanding of these effects by considering a simple one-dimensional network model. The simplicity of our model allows us to use stochastic dynamic programming (SDP) to find the maximum possible network throughput with ideal routing and medium access control (MAC) scheduling. Using the optimal value as a benchmark, we also propose and evaluate the performance of a simple threshold-based heuristic. Unlike the optimal policy which requires considerable state information, the proposed heuristic is simple to implement and is not overly sensitive to the threshold value. We find empirical conditions for our heuristic to be near-optimal. Also, network scenarios when our heuristic does not perform very well are analyzed. We provide extensive numerical analysis and simulation results for different parameter settings of our model. Interestingly, we observe that in low density network the average throughput can first decrease with mobility, and then increase. This motivates us to study a mobile ad-hoc network when it is sparse and in a generalized environment, such as when movement of nodes is in a two-dimension plane. Due to sparseness, there are frequent disruptions in the connections and there may not be any end-to-end connection for delivery. The mobility of nodes may be used for carrying the forwarded message to the destination. This network is also known as a delay tolerant network. In the rest part of the thesis, we consider the relay nodes to be members of a group that charges a price for assisting in message transportation. First, we solve the problem of how to select first relay node when only one relay node can be chosen from a given number of groups. Next, we solve two problems, namely price-constrained delay minimization, and delay-constrained price optimization.

Mobile Ad hoc Networks (MANETs) are of great interest to researchers and have become very popular in the last few years. One of the great challenges is to provide a routing protocol that is capable of offering the shortest and most reliable path in a MANET in which users are moving continuously and have no base station to be used as a reference for their position. This thesis proposes some new routing protocols based on the angles (directions) of the adjacent mobile nodes and also the node density. In choosing the next node in forming a route, the neighbour node with the closest heading angle to that of the node of interest is selected, so the connection between the source and the destination consists of a series of nodes that are moving in approximately the same direction. The rationale behind this concept is to maintain the connection between the nodes as long as possible. This is in contrast to the well known hop count method, which does not consider the connection lifetime. We propose three enhancements and modifications of the Ad-hoc on demand distance vector (AODV) protocol that can find a suitable path between source and destination using combinations and prioritization of angle direction and hop count. Firstly, we consider that if there are multiple routing paths available, the path with the minimum hop count is selected and when the hop counts are the same the path with the best angle direction is selected. Secondly, if multiple routing paths are available the paths with the best angle direction are chosen but if the angles are the same (fall within the same specified segment), the path with minimum hop count is chosen. Thirdly, if there is more than one path available, we calculate the average of all the heading angles in every path and find the best one (lowest average) from the source to the destination. In MANETs, flooding is a popular message broadcasting technique so we also propose a new scheme for MANETS where the value of the rebroadcast packets for every host node is dynamically adjusted according to the number of its neighbouring nodes. A fixed probabilistic scheme algorithm that can dynamically adjust the rebroadcasting probability at a given node according to its ID is also proposed; Fixed probabilistic schemes are one of the solutions to reduce rebroadcasts and so alleviate the broadcast storm problem. Performance evaluation of the proposed schemes is conducted using the Global Mobile Information System (GloMoSim) network simulator and varying a number of important MANET parameters, including node speed, node density, number of nodes and number of packets, all using a Random Waypoint (RWP) mobility model. Finally, we measure and compare the performance of all the proposed approaches by evaluating them against the standard AODV routing protocol. The simulation results reveal that the proposed approaches give relatively comparable overall performance but which is better than AODV for almost all performance measures and scenarios examined.

With the proliferation of mobile devices and wireless connectivity technologies, mobile social communities offer novel opportunities for targeted marketing by service or product providers. Unfortunately, marketers are still unable to realize the full potential of these markets due to their inability to effectively target right audiences. This thesis presents a novel middleware for identifying spontaneous social communities (SSCs) of mobile users in ad hoc networks in order to facilitate marketers' advertisements. The contributions of the presented work are two fold; the first is a novel model for SSCs that captures their unique dynamic nature, in terms of community structure and interest in different \textit{hot-topics} over time. These time-varying interests are represented through an inferred \textit{community profile prototype} that reflects dominant characteristics of community members. This prototype is then employed to facilitate the identification of new potential members. The selected community prototypes are also used by marketers to identify the right communities for their services or products promotions. The second contribution of this paper is novel distributed techniques for efficient calculation of the community prototypes and identification of potential community links. In contrast to traditional models of detecting fixed and mobile social networks that rely on pre-existing friendships among its members to predict new ones, the proposed model focuses on measuring the degree of similarity between the new user's profile and the profiles of members of each community in order to predict new users' relationships in the community. The adopted model of SSCs can foster many existing and new socially-aware applications such as recommender systems for social events and tools for collaborative work. It is also an ideal target for business-oriented applications such as short-message-service (SMS) advertisement messages, podcasting news feeds in addition to location/context-aware services. The performance of the proposed work was evaluated using the NetLogo platform where obtained experimental results demonstrate the achieved high degree of stability in the resulting communities in addition to the effectiveness of the proposed middleware in terms of the reduction in the number of routing messages required for advertisements.