Τα ασύρματα κινητά Ad Hoc δίκτυα γίνονται ολοένα και πιο δημοφιλή λόγω της αυξανόμενης χρήσης κινητών συσκευών. Οι κόμβοι αυτών των δικτύων μπορούν να κινούνται ελεύθερα στον χώρο, έχοντας ταυτόχρονα πολλαπλούς ρόλους αφού μπορούν να λάβουν και να στείλουν πληροφορία προερχόμενη από οποιοδήποτε πόρο του δικτύου. Αυτό σημαίνει ότι ένας κόμβος μπορεί να έχει το ρόλο του αποστολέα, του παραλήπτη και του αναμεταδότη. Η ικανότητα αυτών των δικτύων να αυτοπροσαρμόζονται και να δημιουργούν ένα συνεκτικό δίκτυο μέσω ασύρματων συνδέσεων, τα κάνει κατάλληλα για μια σειρά από εφαρμογές στις οποίες τα άλλα δίκτυα αποτυγχάνουν. Τέτοιες εφαρμογές περιλαμβάνουν τοπολογίες που στήνονται σε συνθήκες έκτακτης ανάγκης, δίκτυα αισθητήρων και γενικά τοπολογίες στις οποίες δεν υπάρχει προκαθορισμένη υποδομή ή η υποδομή που υπήρχε έχει καταστραφεί. Τα ασύρματα κινητά δίκτυα παρέχουν την ελευθερία στους κόμβους να κινηθούν ακόμα και μακρυά από σταθμούς βάσης ή και να αποσυνδεθούν προσωρινά από το υπόλοιπο δίκτυο, με αποτέλεσμα να καθιστούν δύσκολο το πρόβλημα της δρομολόγησης. Τα πρωτόκολλα δρομολόγησης που έχουν αναπτυχθεί για τέτοιου τύπου δίκτυα επηρεάζουν άμεσα τα χαρακτηριστικά της μετάδοσης δεδομένων και την απόδοση των σχετικών εφαρμογών. Κάθε πρωτόκολλο έχει τη δική του στρατηγική δρομολόγησης έτσι ώστε να καταφέρει να συνδέσει δυο κινητούς κόμβους του δικτύου. Η απόδοση μεταβάλλεται ανάλογα με την κατάσταση του δικτύου και τις επικρατούσες συνθήκες όπως η πυκνότητα των κόμβων σε μια συγκεκριμένη περιοχή, η ταχύτητα και η κατεύθυνση τους. Είναι προφανές ότι η επιλογή του κατάλληλου πρωτοκόλλου δρομολόγησης ανάλογα με τα χαρακτηριστικά και τις παραμέτρους του δικτύου παίζει πολύ σημαντικό ρόλο. Η ενσωμάτωση των κινητών συσκευών σε κινούμενα οχήματα έχει οδηγήσει σε έναν νέο τύπο δικτύων, τα ονομαζόμενα Ad Hoc δίκτυα οχημάτων ή Vehicular Ad hoc Networks (VANETs). Αυτά τα δίκτυα απαιτούν εξειδικευμένα πρωτόκολλα δρομολόγησης εξαιτίας της φύσης των κινητών Ad Hoc δικτύων. Η απόδοση αυτών των πρωτοκόλλων έχει αξιολογηθεί για την περίπτωση της γενικευμένης κίνησης αλλά όχι υπό το πρίσμα της μετάδοσης πολυμέσων και ειδικότερα της μετάδοσης βίντεο. Αρχικός στόχος αυτής της εργασίας είναι η πραγματοποίηση ενός συνόλου από εξομοιώσεις με στόχο την αξιολόγηση της απόδοσης των τριών από τα πιο δημοφιλή πρωτόκολλα δρομολόγησης για τα κινητά Ad Hoc δίκτυα MANETs και VANETs: AODV, DSR, και OLSR. Ο σκοπός της αξιολόγησης είναι η μελέτη της συμπεριφοράς των πρωτοκόλλων όταν μεταβάλλεται το πλήθος των ταυτόχρονων μεταδόσεων βίντεο. Οι μετρικές που προτείνονται είναι • το ποσοστό απώλειας πακέτων • η καθυστέρηση από άκρο σε άκρο • η διακύμανση της καθυστέρησης (jitter) • η επιβάρυνση του δικτύου με πακέτα δρομολόγησης Η μετάδοση πολυμέσων μέσα από τα ασύρματα κινητά Ad Hoc δίκτυα δεν είναι πάντοτε αποδοτική εξαιτίας των υψηλών απαιτήσεων που υπάρχουν, όπως το υψηλό εύρος ζώνης και οι χαμηλοί χρόνοι καθυστέρησης. Δηλαδή, αυτά τα δίκτυα δεν δείχνουν ικανά να υποστηρίξουν μεταδόσεις πολυμέσων υψηλής ποιότητας και ειδικότερα μεταδόσεις βίντεο. Στα πλαίσια της εργασίας αναπτύσσεται και παρουσιάζεται ένας διαστρωματικός μηχανισμός για αποδοτική μετάδοση βίντεο πάνω σε ασύρματα Ad Hoc δίκτυα οχημάτων (VANETs). Ο μηχανισμός αυτός αποτελείται από έναν αλγόριθμο χρονοπρογραμματισμού και ανάθεσης προτεραιότητας στο επίπεδο δικτύου. Ακόμα προτείνεται και αξιολογείται η χρήση του προτύπου IEEE 802.11e στο επίπεδο ζεύξης δεδομένων. Ο αλγόριθμος χρονοπρογραμματισμού και ανάθεσης προτεραιότητας στοχεύει στο να αξιοποιεί την πληροφορία που αφορά στον τύπο των πλαισίων των MPEG-4 βίντεο, με στόχο να παρέχει διαφορετικές προτεραιότητες ανάλογα με τη σημαντικότητα του κάθε πλαισίου. Στο επίπεδο ζεύξης δεδομένων το πρωτόκολλο IEEE 802.11e προτείνεται να αναθέτει τη μέγιστη προτεραιότητα στα πακέτα βίντεο με στόχο την καλύτερη εξυπηρέτηση των εφαρμογών μετάδοσης πολυμέσων. Αυτή η επιλογή γίνεται για τη μείωση της καθυστέρησης και της απώλειας πακέτων εξαιτίας της κίνησης ανταγωνιστικών δεδομένων. Ο σχεδιασμός που παρουσιάζεται είναι εύκολα ενσωματώσιμος σε κάθε ασύρματο Ad Hoc δίκτυο, σαν επέκταση του δημοφιλούς πρωτοκόλλου δρομολόγησης AODV. Οι εφαρμογές μετάδοσης πολυμέσων συνήθως χρησιμοποιούν το UDP ως πρωτόκολλο μεταφοράς. Με αυτή την επιλογή αποφεύγονται οι καθυστερήσεις που προκαλούνται από αναμεταδόσεις πακέτων και από τους μηχανισμούς ελέγχου συμφόρησης του TCP, αλλά δημιουργούνται δυο σημαντικά προβλήματα. Το πρώτο πρόβλημα έχει να κάνει με τους πιθανούς περιορισμούς εύρους ζώνης με αποτέλεσμα τα πακέτα πολυμέσων να μην ελέγχονται από μηχανισμούς ελέγχου ροής και συμφόρησης, οδηγώντας σε αυξημένη απώλεια πακέτων. Το δεύτερο πρόβλημα είναι σχετικό με τη φιλικότητα προς το TCP πρωτόκολλο. Κάτω υπό ορισμένες συνθήκες, η μετάδοση πακέτων χωρίς κάποιον ελεγκτικό μηχανισμό μπορεί να οδηγήσει σε μια κατάσταση στην οποία οι εφαρμογές του δικτύου που χρησιμοποιούν το TCP να μην εξυπηρετούνται. Στα πλαίσια της εργασίας προτείνονται διαστρωματικές τεχνικές και μηχανισμοί που στοχεύουν στη βελτίωση της μετάδοσης βίντεο, μέσω του πρωτοκόλλου TFRC το οποίο είναι φιλικό ως προς την συνυπάρχουσα TCP κίνηση. Ο σχεδιασμός περιλαμβάνει μηχανισμούς που δίνουν προτεραιότητα στα πακέτα βίντεο, ενώ παράλληλα αξιοποιούνται πληροφορίες από τα κατώτερα επίπεδα του μοντέλου OSI. Συγκεκριμένα, αξιοποιούνται πληροφορίες που συλλέγονται από το στρώμα ζεύξης δεδομένων οι οποίες αφορούν την ποιότητα του λαμβανόμενου σήματος. Ο προτεινόμενος μηχανισμός χρησιμοποιεί τις μετρήσεις της ενέργειας σήματος ως προς τον θόρυβο του καναλιού (SNR) σε όλο το μήκος ενός μονοπατιού, προκειμένου να βελτιώσει την αποδοτικότητα του πρωτοκόλλου δρομολόγησης AODV και συγκεκριμένα τη διαδικασία ανακατασκευής μονοπατιών. Η αξιολόγηση που προτείνεται είναι με εξομοιώσεις στον εξομοιωτή δικτύων ns-2. Συμπερασματικά, στόχος αυτής της διπλωματικής εργασίας είναι η μελέτη μετάδοσης πολυμεσικών δεδομένων μέσω διαφόρων πρωτοκόλλων δρομολόγησης σε συνθήκες αστικού περιβάλλοντος. Επίσης, στόχος είναι η μελέτη και η ανάπτυξη διαστρωματικών μηχανισμών προσαρμοστικής μετάδοσης και η πιθανή βελτίωση ή παραμετροποίηση υπαρχόντων μηχανισμών για την αποδοτικότερη μετάδοση πάνω από τα ασύρματα κινητά Ad Hoc δίκτυα. Ο κεντρικός άξονας στην ανάπτυξη αυτών των μηχανισμών στηρίζεται στην παροχή προτεραιότητας στα πακέτα που περιέχουν δεδομένα πολυμέσων, στην ενίσχυση των μηχανισμών ελέγχου ροής και συμφόρησης και στη βελτίωση των πρωτοκόλλων δρομολόγησης αξιοποιώντας στοιχεία του φυσικού δικτύου, με απώτερο στόχο τη βελτίωση της απόδοσης της μετάδοσης πολυμεσικών δεδομένων. / Mobile ad hoc networks (MANETs) are becoming more essential to wireless commu- nications due to growing popularity of mobile devices. The integration of mobile ad hoc devices inside vehicles has led to another type of networks, called Vehicular Ad hoc Networks (VANETs) which are also becoming important. These networks require specialized routing protocols due to their ad hoc nature. The performance of these pro- tocols has been tested for the case of general traffic but not in respect with to multimedia traffic and especially video transmission. In this work we conduct a number of simulations in order to evaluate the performance of three of the most popular routing protocols for MANETs and VANETs, namely AODV, DSR and OLSR, for different number of simultaneous video transmissions. We use the packet delivery ratio, the end-to-end delay, the packet delay variation (jit- ter) and the routing overhead as evaluation metrics. The results indicate that the DSR protocol outperforms AODV and OLSR in terms of end-to-end delay and packet delay variation and seems to be the most efficient routing protocol when multimedia traffic and especially video traffic is considered. Moreover, we present a cross-layer mechanism for efficient video transmission over this type of networks. The proposed mechanism consists of a priority-scheduling algorithm, at the network layer, and the use of the IEEE 802.11e standard at the MAC layer. The priority-scheduling algorithm takes into account the frame type of the MPEG-4 video file in order to provide different priorities to the most important video packets. At the MAC layer, the IEEE 802.11e protocol assigns the highest priority to video applications to reduce delay and packets losses due to other competing traffic. This design is easily implemented in any ad hoc wireless network as an extension on the AODV MANET routing protocol. Simulation results conducted with the network simulator ns-2 show the advantages of the proposed design. Finally, we propose a cross-layer design that aims to improve the performance of video transmission using TCP Friendly Rate Control (TFRC). Our design provides priority to video packets and exploits information from the MAC layer in order to improve TFRC’s performance. The proposed cross-layer mechanism utilizes Signal to Noise Ratio (SNR) measurements along the routing path, in order to make the route recon- struction procedure more efficient. Simulation results show that both the use of traffic categorization and the SNR utilization lead to important improvements of video trans- mission over the mobile Ad hoc network. More specifically, simulations indicate in- creased average Peak Signal to Noise Ratio (PSNR) for the received video, increased throughput and packet delivery ration, as well as reduced average end-to-end delay.

The popularity of wireless communication has increased substantially over the last decade, due to mobility support, flexibility and ease of deployment. Among next generation of mobile communication technologies, Ad Hoc networking plays an important role, since it can stand alone as private network, become a part of public network, either for general use or as part of disaster management scenarios. The performance of multihop Ad Hoc networks is heavily affected by interference, mobility, limited shared bandwidth, battery life, error rate of wireless media, and the presence of hidden and exposed terminals. The scheduler and the Medium Access Control (MAC) play a vital role in providing Quality of Service (QoS) and policing delay, end-to-end throughput, jitter, and fairness for user application services. This project aims to optimise the usage of the available limited resources in terms of battery life and bandwidth, in order to reduce packet delivery time and interference, enhance fairness, as well as increase the end-to-end throughput, and increase the overall network performance. The end-to-end throughput of an Ad Hoc network decays rapidly as the hop count between the source and destination pair increases and additional flows injected along the path of an existing flow affects the flows arriving from further away; in order to address this problem, the thesis proposes a Hop Based Dynamic Fair Scheduler that prioritises flows subject to the hop count of frames, leading to a 10% increase in fairness when compared to a IEEE 802.11b with single queue. Another mechanism to improve network performance in high congestion scenarios is network-aware queuing that reduces loss and improve the end-to-end throughput of the communicating nodes, using a medium access control method, named Dynamic Queue Utilisation Based Medium Access Control (DQUB-MAC). This MAC provides higher access probability to the nodes with congested queue, so that data generated at a high rate can be forwarded more effectively. Finally, the DQUB-MAC is modified to take account of hop count and a new MAC called Queue Utilisation with Hop Based Enhanced Arbitrary Inter Frame Spacing (QU-EAIFS) is also designed in this thesis. Validation tests in a long chain topology demonstrate that DQUB-MAC and QU-EAIFS increase the performance of the network during saturation by 35% and 40% respectively compared to IEEE 802.11b. High transmission power leads to greater interference and represents a significant challenge for Ad Hoc networks, particularly in the context of shared bandwidth and limited battery life. The thesis proposes two power control mechanisms that also employ a random backoff value directly proportional to the number of the active contending neighbours. The first mechanism, named Location Based Transmission using a Neighbour Aware with Optimised EIFS for Ad Hoc Networks (LBT-NA with Optimised EIFS MAC), controls the transmission power by exchanging location information between the communicating nodes in order to provide better fairness through a dynamic EIFS based on the overheard packet length. In a random topology, with randomly placed source and destination nodes, the performance gain of the proposed MAC over IEEE 802.11b ranges from approximately 3% to above 90% and the fairness index improved significantly. Further, the transmission power is directly proportional to the distance of communication. So, the performance is high and the durability of the nodes increases compared to a fixed transmission power MAC such as IEEE 802.11b when communicating distance is shorter. However, the mechanism requires positional information, therefore, given that location is typically unavailable, a more feasible power control cross layered system called Dynamic Neighbour Aware – Power controlled MAC (Dynamic NA -PMAC)is designed to adjust the transmission power by estimating the communicating distance based on the estimated overheard signal strength. In summary, the thesis proposes a number of mechanisms that improve the fairness amongst the competing flows, increase the end-to-end throughput, decrease the delay, reduce the transmission power in Ad Hoc environments and substantially increase the overall performance of the network.

This thesis presents a framework for investigating opportunistic routing in Delay Tolerant Mobile Ad hoc Networks (DTMANETs), and introduces the concept of an Opportunistic Confidence Index (OCI). The OCI enables multiple opportunistic routing protocols to be applied as an adaptive group to improve DTMANET routing reliability, performance, and efficiency. The DTMANET is a recently acknowledged networkarchitecture, which is designed to address the challenging and marginal environments created by adaptive, mobile, and unreliable network node presence. Because of its ad hoc and autonomic nature, routing in a DTMANET is a very challenging problem. The design of routing protocols in such environments, which ensure a high percentage delivery rate (reliability), achieve a reasonable delivery time (performance), and at the same time maintain an acceptable communication overhead (efficiency), is of fundamental consequence to the usefulness of DTMANETs. In recent years, a number of investigations into DTMANET routing have been conducted, resulting in the emergence of a class of routing known as opportunistic routing protocols. Current research into opportunistic routing has exposed opportunities for positive impacts on DTMANET routing. To date, most investigations have concentrated upon one or other of the quality metrics of reliability, performance, or efficiency, while some approaches have pursued a balance of these metrics through assumptions of a high level of global knowledge and/or uniform mobile device behaviours. No prior research that we are aware of has studied the connection between multiple opportunistic elements and their influences upon one another, and none has demonstrated the possibility of modelling and using multiple different opportunistic elements as an adaptive group to aid the routing process in a DTMANET. This thesis investigates OCI opportunities and their viability through the design of an extensible simulation environment, which makes use of methods and techniques such as abstract modelling, opportunistic element simplification and isolation, random attribute generation and assignment, localized knowledge sharing, automated scenario generation, intelligent weight assignment and/or opportunistic element permutation. These methods and techniques are incorporated at both data acquisition and analysis phases. Our results show a significant improvement in all three metric categories. In one of the most applicable scenarios tested, OCI yielded a 31.05% message delivery increase (reliability improvement), 22.18% message delivery time reduction (performance improvement), and 73.64% routing depth decrement (efficiency improvement). We are able to conclude that the OCI approach is feasible across a range of scenarios, and that the use of multiple opportunistic elements to aid decision-making processes in DTMANET environments has value.

ORTIZ, Marcos Dantas. Incentivando a cooperação em redes Ad Hoc. 2007. 94 f. Dissertação (Mestrado em ciência da computação)- Universidade Federal do Ceará, Fortaleza-CE, 2007. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-07-11T19:12:29Z No. of bitstreams: 1 2007_dis_mdortiz.pdf: 3285277 bytes, checksum: 0ed0f9fb8049649eb6665ffbf256a2c0 (MD5) / Approved for entry into archive by Rocilda Sales (rocilda@ufc.br) on 2016-07-20T12:02:11Z (GMT) No. of bitstreams: 1 2007_dis_mdortiz.pdf: 3285277 bytes, checksum: 0ed0f9fb8049649eb6665ffbf256a2c0 (MD5) / Made available in DSpace on 2016-07-20T12:02:11Z (GMT). No. of bitstreams: 1 2007_dis_mdortiz.pdf: 3285277 bytes, checksum: 0ed0f9fb8049649eb6665ffbf256a2c0 (MD5) Previous issue date: 2007 / Mobile Ad Hoc Networks (MANETs) refer to the wireless networks without a fixed infrastructure and a central administration. In this way, the communication management is self-organized by the mobile nodes in the network. The mobile nodes in MANETs can have a router role. These nodes are known as intermediate nodes and they have na important role to maintain the network connectivity forwarding packets for the benefit of other nodes. Because the small range of the radio transmission, most of the móbile nodes (sender and receiver) cannot usually communicate with each other directly. So the communications are relying on multihop routing. Routing protocols for MANETs assume that the nodes are willing to participate in the cooperative packets forwarding, however, in the packet transmission stage it is verified a great resource consumption (e.g., processing and energy). Since forwarding a packet will incur a cost of energy to a node, the nodes can have a selfish behavior avoiding send packets to save their resources. This work describes an autonomous strategy to provide an incentive for mobile nodes to cooperate in a credit-based system. A node receives credit for forwarding a packet while the sender node looses credit. As an incentive for mobile nodes to cooperate they receive a better quality of service (QoS). This strategy uses the amount of credits to classify the ows inside routers nodes. This strategy uses only local information and it does not have a central entity to manage the credit of the nodes. The simulations show that this strategy is efiective to prioritize packets sent by cooperative nodes. / Redes móveis Ad Hoc (Mobile Ad Hoc Network - MANET) são redes sem fio que não possuem infra-estrutura de comunicação fixa e administração centralizada. Dessa forma, o gerenciamento da comunicação é realizado pelos próprios dispositivos, que, além de transmitir e receber pacotes pode funcionar como roteadores. Na função de roteador, os dispositivos executam um papel fundamental para manutenção da conectividade da rede, o encaminhamento de pacotes. Devido ao pequeno alcance dos rádios de transmissão, nem sempre é possível a comunicação direta entre os dispositivos origem e destino. Dessa forma, grande parte das comunicações é realizada através do encaminhamento de pacotes por múltiplos saltos. Os dispositivos que realizam o encaminhamento de pacotes são chamados de nós intermediários. Os protocolos de roteamento desenvolvidos para MANETs assumem que o encaminhamento cooperativo de pacotes é sempre vantajoso para os dispositivos, no entanto, é sabido que na fase de transmissão de um pacote é verificado o maior consumo de recursos (e.g., processamento e energia). Nas MANETs de uso civil, em que os objetivos e as métricas de desempenho dos integrantes são diversos, os dispositivos podem apresentar um comportamento egoísta, através do não encaminhamento de pacotes, como forma de economizar seus recursos. Este trabalho apresenta uma estratégia autônoma de incentivo á cooperação baseada no uso de créditos. Os dispositivos que encaminham pacotes recebem em troca créditos, enquanto os dispositivos que originam pacotes perdem créditos. Como incentivo, o encaminhamento prioritário de pacotes fornece uma melhor Qualidade de Serviço (QoS) aos nós que possuem créditos. A estratégia utiliza apenas informações locais e não há necessidade de uma entidade central para gerenciar os créditos dos nós. Através de simulações, foram realizados vários experimentos em que foi verificada a eficácia desta estratégia no encaminhamento prioritário dos pacotes gerados pelos nós cooperativos.

Les théâtres d’opérations militaires s’organisent aujourd’hui sous la forme de coalitions. Les forces armées qui sont déployées possèdent des moyens technologiques (communication, routage) et créent des réseaux sans fil. Le mouvement de ces forces sur le terrain donne au réseau une topologie fortement dynamique. Il se caractérise comme un réseau sans fil mobile, plus communément appelé MANET (Mobile Ad hoc NETwork). Pour l’efficacité de la mission et des communications, il est intéressant d’interconnecter facilement les différents groupes participant à la coalition. Cependant, chaque membre de la coalition possède sa propre architecture et souhaite rester autonome, sans s’adapter aux autres. Comme les opérateurs ont pu le faire lors de la création de l’Internet avec le protocole BGP (Border Gateway Protocol), il est nécessaire de créer un protocole qui connecte tous ces groupes participant à la coalition. Ce protocole doit permettre de créer des connexions inter-groupes, supporter facilement les changements de topologies et appliquer des politiques de routage qui permettent d’indiquer des préférences de groupes à emprunter, par exemple. Dans cette thèse, nous allons dans un premier temps étudier la non-adaptabilité de BGP sur les réseaux MANET. Puis, nous étudierons les différentes propositions de la littérature. Ensuite, nous présenterons notre solution ITMAN (Inter Tactical Mobile Ad hoc Network) dans sa première version et les améliorations que nous avons pu y apporter. Enfin, nous terminerons ce manuscrit par les perspectives qui peuvent être menées suite à cette thèse. / Nowadays, military operations are organized as coalitions. The armed forces that are deployed have technological features (communication, routing) that create wireless networks. The mobility of these forces on the ground means that the network has a highly dynamic topology. This is a mobile wireless network, more commonly called MANET (Mobile Ad hoc NETwork). For mission and communication efficencies, interconnection between the various groups participating in the coalition is necessary. However, each member of the coalition has its own architecture and wants to keep independancy from the other groups technologies. This situation is similar as the Internet construction, where operators were able to interconnect their infrastructures with BGP (Border Gateway Protocol). It is important to create a protocol that can connect all the groups involved in the coalition. This protocol should allow inter-group connections, easily support topology changes and apply routing policies that specifies groups on the route preferences, for example. In this thesis, we first study the adaptability issues of BGP on MANET. Then, we study the proposals that have been made in the literature. Next, we present ITMAN (Inter Tactical Mobile Ad Hoc Network) in its first version and the improvements that have been made. Finally, we will conclude this manuscript with the perspectives that can be highlighted following this thesis.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Redes mÃveis Ad Hoc (Mobile Ad Hoc Network - MANET) sÃo redes sem fio que nÃo possuem infra-estrutura de comunicaÃÃo fixa e administraÃÃo centralizada. Dessa forma, o gerenciamento da comunicaÃÃo à realizado pelos prÃprios dispositivos, que, alÃm de transmitir e receber pacotes pode funcionar como roteadores. Na funÃÃo de roteador, os dispositivos executam um papel fundamental para manutenÃÃo da conectividade da rede, o encaminhamento de pacotes. Devido ao pequeno alcance dos rÃdios de transmissÃo, nem sempre à possÃvel a comunicaÃÃo direta entre os dispositivos origem e destino. Dessa forma, grande parte das comunicaÃÃes à realizada atravÃs do encaminhamento de pacotes por mÃltiplos saltos. Os dispositivos que realizam o encaminhamento de pacotes sÃo chamados de nÃs intermediÃrios. Os protocolos de roteamento desenvolvidos para MANETs assumem que o encaminhamento cooperativo de pacotes à sempre vantajoso para os dispositivos, no entanto, à sabido que na fase de transmissÃo de um pacote à verificado o maior consumo de recursos (e.g., processamento e energia). Nas MANETs de uso civil, em que os objetivos e as mÃtricas de desempenho dos integrantes sÃo diversos, os dispositivos podem apresentar um comportamento egoÃsta, atravÃs do nÃo encaminhamento de pacotes, como forma de economizar seus recursos. Este trabalho apresenta uma estratÃgia autÃnoma de incentivo à cooperaÃÃo baseada no uso de crÃditos. Os dispositivos que encaminham pacotes recebem em troca crÃditos, enquanto os dispositivos que originam pacotes perdem crÃditos. Como incentivo, o encaminhamento prioritÃrio de pacotes fornece uma melhor Qualidade de ServiÃo (QoS) aos nÃs que possuem crÃditos. A estratÃgia utiliza apenas informaÃÃes locais e nÃo hà necessidade de uma entidade central para gerenciar os crÃditos dos nÃs. AtravÃs de simulaÃÃes, foram realizados vÃrios experimentos em que foi verificada a eficÃcia desta estratÃgia no encaminhamento prioritÃrio dos pacotes gerados pelos nÃs cooperativos. / Mobile Ad Hoc Networks (MANETs) refer to the wireless networks without a fixed infrastructure and a central administration. In this way, the communication management is self-organized by the mobile nodes in the network. The mobile nodes in MANETs can have a router role. These nodes are known as intermediate nodes and they have na important role to maintain the network connectivity forwarding packets for the benefit of other nodes. Because the small range of the radio transmission, most of the mÃbile nodes (sender and receiver) cannot usually communicate with each other directly. So the communications are relying on multihop routing. Routing protocols for MANETs assume that the nodes are willing to participate in the cooperative packets forwarding, however, in the packet transmission stage it is verified a great resource consumption (e.g., processing and energy). Since forwarding a packet will incur a cost of energy to a node, the nodes can have a selfish behavior avoiding send packets to save their resources. This work describes an autonomous strategy to provide an incentive for mobile nodes to cooperate in a credit-based system. A node receives credit for forwarding a packet while the sender node looses credit. As an incentive for mobile nodes to cooperate they receive a better quality of service (QoS). This strategy uses the amount of credits to classify the ows inside routers nodes. This strategy uses only local information and it does not have a central entity to manage the credit of the nodes. The simulations show that this strategy is efiective to prioritize packets sent by cooperative nodes.

The thesis investigates the process of modeling and simulation of the mobile ad-hoc networks. It provides a overview of the actual state of art together with a literature survey. Basic ideas of both security issues in mobile ad-hoc networks as well as intrusion detection systems are presented. Additionally some new ideas for improvements - like the AGM mobility model - are proposed, and tested during the simulation proces. As an addition a set of applications designer for automating the simulation processes were created.

L’émergence de véhicules aériens sans pilote, généralement appelés drones, petits et bon marché favorise leur utilisation dans le domaine des applications civiles. Ces drones sont équipés de différents capteurs et ont la capacité de communiquer via des liaisons sans fil et ont la particularité de se déplacer librement dans l’espace, révolutionnant la gestion des applications de surveillance. Un réseau ad hoc de drones, Flying Ad hoc Networks (FANET) en anglais, est composé d’une flotte de drones autonomes et est utilisé lors de missions dans des environnements hostiles pour la surveillance ou l’inspection de sites dangereux ou inconnus. Les FANETs peuvent être également utilisés pour suivre et filmer des événements spéciaux comme une course de vélos ou un match de football, dans ce cas les liaisons doivent garantir un minimum de qualité. Les FANETs nécessitent une attention particulière en ce qui concerne l’économie d’énergie des UAV dont les ressources en énergie sont limitées, mais aussi d’être immunisés contre des attaques malveillantes. Au cours de cette thèse, nous nous sommes concentrés sur le problème de suivi d’une cible mobile utilisant une flotte de drones pour la filmer. Étant donné que la cible se déplace, les drones doivent la suivre en continu, et une liaison vers la station terrestre doit être disponible. Dans ce contexte, nous proposons une solution qui permet la coordination d’un ensemble de drones afin de maintenir un chemin optimal entre la cible et la station terrestre. Notre solution se révèle efficace en matière de gain en temps et en énergie. Nous avons également proposé une solution basée sur des protocoles hiérarchiques pour économiser plus d’énergie dans le processus de communication avec la station terrestre. Nous avons également développé une autre solution qui permet d’économiser plus d’énergie en forçant les nœuds égoïstes à participer dans le réseau et d’assurer le relais de paquets lorsqu’ils sont sollicités. En effet, si un nœud égoïste refuse de router des paquets d’autres nœuds, cela induit une charge supplémentaire pour le reste des nœuds du réseau. Nous avons validé l’apport de l’ensemble de nos solutions par évaluation de performances à l’aide de simulations. / The emergence of small and inexpensive Unmanned Aerial Vehicles (UAVs) promotes their use in several applications. UAVs are usually equipped with different sensors and have the ability to communicate via wireless connections. Their capability to fly freely in the space offers new opportunities to monitoring and tracking applications. A Flying Ad hoc Network (FANET) is composed of a fleet of autonomous UAVs and is used for monitoring applications in hostile environments, surveillance or site inspection. FANETs could also be used for filming special events such as bike races or soccer matches, so, the connections must guarantee a minimum of quality of service. In FANETs, saving energy of UAVs that have limited battery is very challenging and protecting the network from malicious attacks is even more difficult. In this thesis, we focus on tracking and filming a moving target using a fleet of UAVs. Since the target is moving, the UAVs have to follow it continuously, and a path to the ground station must be available. In this context, we propose an efficient solution that allows the coordination of the UAVs to maintain an optimal path between the target and the ground station. The proposed solution is time and energy efficient. We also propose a solution based on hierarchical protocols to save more energy in the communication process with the ground station. Another solution that allows energy saving is to force selfish nodes to participate in the network to route received packets towards their destination. Indeed, a selfish node is concerned only about its own welfare, refusing to route packets of other node, causing an extra charge for the rest of nodes in the network. We validate our solutions through simulation campaigns.

An Ad Hoc network is a wireless network without any stationary infrastructure of any kind. The nodes should be able to communicate with each other using wireless links, where a packet might traverse multiple links from the source to the destination. Every node in the network acts as a router, forwarding packet from one node to another. Since Ad Hoc networks are wireless and the nodes often battery driven, it is very important that the routing protocol in use can handle a large degree of node mobility and at the same time be very energy efficient. This is not an easy thing and a numerous routing protocols for wireless Ad Hoc networks have been proposed. Our goal was to simulate and make a literature study of three completely different routing protocols for wireless Ad Hoc networks: the Dynamic Source Routing protocol (DSR), the Topology Dissemination Based on Reverse-Path Forwarding protocol (TBRPF), and the Zone Routing Protocol (ZRP).

Mobile Ad Hoc Networks are flexible, self configuring networks that do not need a fixed infrastructure. When these nets are simulated, mobility models can be used to specify node movements. The work in this thesis focuses on designing an extension of the random trip mobility model on a city section from EPFL (Swiss federal institute of technology). Road data is extracted from the census TIGER database, displayed in Google Earth and used as input for the model. This model produces output that can be used in the open source network simulator ns-2. We created utilities that take output from a database of US counties, the TIGER database, and convert it to KML. KML is an XML based format used by Google Earth to store geographical data, so that it can be viewed in Google Earth. This data will then be used as input to the modified mobility model and finally run through the ns-2 simulator. We present some NAM traces, a network animator that will show node movements over time. We managed to complete most of the goals we set out, apart from being able to modify node positions in Google Earth. This was skipped because the model we modified had an initialization phase that made node positions random regardless of initial position. We were also asked to add the ability to set stationary nodes in Google Earth; this was not added due to time constraints.