Acoustic networks of autonomous underwater vehicles (AUVs) show great promise, but a lack of simulation tools and reliance on protocols originally developed for terrestrial radio networks has hindered progress. This work addresses both issues. A new simulator of underwater communication among AUVs provides accurate communication modeling and flexible vehicle behavior, while a new routing protocol, location-aware source routing (LASR) provides superior network performance. The new simulator was used to evaluate communication without networking, and then with networking using the coding or dynamic source routing (DSR) protocols. The results confirmed that a network was essential to ensure effective fleet-wide communication. The flooding protocol provided extremely reliable communication but with low message volumes. The DSR protocol, a popular routing protocol due to its effectiveness in terrestrial radio networks, proved to be a bad choice in an acoustic environment: in most cases, it suffered from both poor reliability and low message volumes. Due to the high acoustic latency, even moderate vehicle speeds caused the network topology to change faster than DSR could adapt. DSR's reliance on shortest-path routing also proved to be a significant disadvantage. Several DSR optimizations were also tested; most proved to be unhelpful or actually harmful in an underwater acoustic network. LASR was developed to address the problems noted in flooding and DSR. LASR was loosely derived from DSR, most significantly retaining source routes and the reply/request route discovery technique. However, LASR added features which proved, in simulation, to be significant advantages -- two of the most effective were a link/route metric and a node tracking system. To replace shortest-path routing, LASR used the expected transmission count (ETX) metric. / This allowed LASR to make more informed routing decisions which greatly increased performance compared to DSR. The node tracking system was the most novel addition: using only implicit communication coupled with the use of time-division multiple access (TDMA), the tracking system provided predicted node locations. These predictions made it possible for LASR to proactively respond to topology changes. In most cases, LASR outperformed flooding and DSR in message delivery reliability and message delivery volume. / by Edward A. Carlson. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Controlling the cooperative behaviors of a fleet of autonomous underwater vehicles in a stochastic, complex environment is a formidable challenge in artificial intelligence. The complexity arises from the challenges of limited navigation and communication capabilities of underwater environment. A time critical cooperative operation by acoustic networks of Multiple Cooperative Vehicles (MCVs) necessitates a robust task allocation mechanism and an efficient path planning model. In this work, we present solutions to investigate two aspects of the cooperative schema for multiple underwater vehicles under realistic underwater acoustic communications: a Location-aided Task Allocation Framework (LAAF) algorithm for multi-target task assignment and a mathematical programming model, the Grid-based Multi-Objective Optimal Programming (GMOOP), for finding an optimal vehicle command decision given a set of objectives and constraints. We demonstrate that, the location-aided auction strategies perform significantly better than the generic auction algorithm in terms of effective task allocation time and information bandwidth requirements. In a typical task assignment scenario, the time needed in the LAAF algorithm is only a fraction compared to the generic auction algorithm. On the other hand; the GMOOP path planning technique provides a unique means for multi-objective tasks by cooperative agents with limited communication capabilities. Under different environmental settings, the GMOOP path planning technique is proved to provide a method with balance of sufficient expressive power and flexibility, and its solution algorithms tractable in terms of mission completion time, with a limited increase of overhead in acoustic communication. Prior to this work, existing multi-objective action selection methods were limited to robust networks where constant communication available. / The dynamic task allocation, together with the GMOOP path planning controller, provides a comprehensive solution to the search-classify tasks for cooperative AUVs. / by Yueyue Deng. / Thesis (Ph.D.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

The scalability of QUIC-TCP was examined by expanding previous developmental 11-node, 4-flow topology to over 30 nodes with 11 flows to validate QUIC-TCP for larger networks. The topology was simulated using ns-2 network simulator with the same ns-2 module of FAST-TCP modified to produce QUIC-TCP agent that the original development used. A symmetrical topology and a random topology were examined. Fairness, aggregate throughput and the object of the utility function were used as validation criteria. It was shown through simulation that QUICTCP optimized the utility function and demonstrated a good balance between aggregate throughput and fairness; therefore QUIC-TCP is indeed scalable to larger networks. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2013.

Cognitive radio technology that enables dynamic spectrum access has been a promising solution for the spectrum scarcity problem. Cognitive radio networks enable the communication on both licensed and unlicensed channels, having the potential to better solve the interference and collision issues. Channel assignment is of great importance in cognitive radio networks. When operating on licensed channels, the objective is to exploit spectrum holes through cognitive communication, giving priority to the primary users. In this dissertation, we focus on the development of efficient channel assignment algorithms and protocols to improve network performance for cognitive radio wireless networks. The first contribution is on channel assignment for cognitive radio wireless sensor networks aiming to provide robust topology control, as well as to increase network throughput and data delivery rate. The approach is then extended to specific cognitive radio network applications achieving improved performances. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

A Wireless Sensor Network (WSN) is composed of low-cost electronic devices with sensing, data storage and transmitting capabilities, powered by batteries. There are extensive studies in the field of WSN investigating different algorithms and protocols for data collection. A data collector can be static or mobile. Using a mobile data collector can extend network lifetime and can be used to collect sensor data in hardly accessible locations, partitioned networks, and delay-tolerant networks. The implementation of the mobile data collector in our study consists of combining two different platforms: the Crossbow sensor hardware and the NXT Legos. We developed an application for data collection and sensor querying support. Another important contribution is designing a semi-autonomous robot control. This hardware prototype implementation shows the benefits of using a mobile data collector in WSN. It also serves as a reference in developing future applications for mobile WSNs. / by Pedro L. Heshike. / Thesis (M.S.C.S.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

The safety-message dissemination problem for vehicular ad hoc networks (VANETs) was investigated. Four novel techniques were contributed for the efficient and reliable routing of safety messages in the vehicular ad hoc networks. The instant-broadcast technique was proposed to improve the end-to-end dissemination delay. The lane-based sectoring mechanism was presented for the collision mitigation in the dense-urban traffic scenario. The negative acknowledgment with smart neighborhood (NSN) technique was proposed to ensure the reliability of reception through recovering the packet loss caused by interference. Finally, the negative acknowledgment with smart neighborhood - hole recovery (NSN-H) technique was presented to provide guaranteed reception of the safety message at each individual node in the VANET. The investigation of the safety message routing in VANET conducted in this research also revealed the significance of hitherto-neglected factors that influence the vehicular network. Significance of the small payload size of the VANET safety message, the effect of road width on the multi-hop relay, and the attenuation caused by vehicles in the propagation path were among the important revealed factors.

The development of miniaturized radio and sensing technologies have enabled the deployment of large quantities of wireless sensors capable of forming multi-hop networks. Emerging applications of this technology such as surveillance and disaster monitoring have throughput and efficiency requirements not met by current routing algorithms. These requirements are also shared by ad-hoc networks. Early routing protocols for these wireless networks were based on algorithms designed for wired networks. Geographic routing (routing based on position), was proposed. These algorithms perform poorly since they do not account for the fading and interference effects of wireless channels. Recent protocols that have attempted to account for the wireless channel focus on single-hop situations and are not readily extensible to multi-hop networks. In this thesis we present a framework for routing based on a distributed routing decision and provide several example protocols. This framework provides a cross-layer design where the routing decision is decided through silent negotiation between candidate relays. We investigate the performance and parameters of this framework. We then present an example protocol using this framework which provides low-overhead opportunistic routing using cooperative diversity. This protocol uses the intrinsic characteristics of the wireless channel to achieve diversity while still maintaining relatively low overhead. An adaptation of the protocol for heterogeneous networks equipped with multiple antennas has also been discussed and evaluated through simulations. We also investigate another protocol based on this framework using the product of the instantaneous packet reception rate and the marginal progress towards the destination as a routing metric, offering enhanced throughput.

M. Tech. Electrical engineering. / Discusses the interference and bandwidth adjusted ETX routing metric uses a logical interference model that refers to the interference arising from the Carrier Sensing Multiple Access with Collision Avoidance (CSMA-CA) based Medium Access Control. This approach of capturing inter-flow is complex and more restrictive. In this dissertation, a more realistic and less restrictive approach based on the information available at the physical layer (signal strength) is used to capture the interference.In contrast to the logical interference model, this has the excellent advantage of measuring the parameters using online data traffic. The question is whether actual capacity improvements can be achieved by considering the physical interference model.

D. Tech. Electrical Engineering. / Discusses the protocol design in VANETs is very challenging due to their low latency and high data rate requirements in a high mobility environment. Hence, the central metrics of QoS such as throughput, reliability and delays are critical to the design of protocol in VANETs. Therefore, this project focuses on the scheduling and QoS enhancement algorithms. The QoS analytical model and multi-channel MAC protocol were completed; this was significant for the development of the VANETs.The anticipated benefits of this study may be described as: 1. The duty cycle adaptive MAC protocol could improve the QoS of VANET in the situation where the OBU is equipped with only one transceiver. 2. The results obtained from this model is significant for the designing and evaluation of the vehicular network. 3. Due to the characteristics of VANETs, the requirements of high throughput and low latency are critical in VANETs. An efficient multi-channel MAC protocol is a vital requirement in order to offer efficient, fair and stable channel access using the limited channel resources.

[Truncated abstract] An ad-hoc network of wireless nodes is a temporarily formed network, created, operated and managed by the nodes themselves. Due to its peculiar establishment and operational properties it is also often termed an infrastructure-less, self-organised, or spontaneous network. In order to extend the communication range of the nodes, beyond a single hop, specially configured routing protocols are used. The unique feature of these protocols is their ability to form routes in spite of a dynamic topology. For effective functioning of the network it is essential that the network nodes execute the routing protocols in a truthful manner regardless of their contemporary commitments and workload. In real life, this is more than often extremely difficult to realise, and so we often find malicious nodes also present in the same network. These nodes can either join externally or may originate internally by compromis- ing an existing benevolent node in the network. These malicious nodes can carry out an array of attacks against the routing protocols leading to route severing, unavailability of service or deception. A number of secure routing protocols, which make use of cryptographic algorithms to secure the routes, have recently been proposed. ... In order to sustain the improvised nature of ad-hoc networks, in this thesis, we have moved from the common mechanism of achieving trust via security to enforcing dependability through collaboration. We desist from the customary strategy of employing cryptography and instead use a trust model that is influ- enced by the human behavioural model. All nodes in the network independently execute this trust model and maintain their own assessment concerning other nodes in the network. Each node, based upon its individual experiences, rewards collabo- rating nodes for their benevolent behaviour and penalises malicious nodes for their malevolent conduct. To highlight the efficacy of this unique approach, we apply the trust model to three contemporary reactive routing protocols in a pure ad-hoc network. These trust reinforced routing protocols locate dependable routes in the network by observing the sincerity in participation of other nodes using a set of trust categories. The routes worked out in this way are neither protected in terms of security nor minimal in terms of hops. However, these routes traverse nodes, which have been identified as more trustworthy than others and for this reason are more dependable in extemporised circumstances. Through the help of extensive simulations, we have demonstrated that the usage of these protocols significantly improves the overall performance of the network even in the presence of a high percentage of malicious nodes. These protocols, being independent of a trust infrastructure, also enable rapid deployment and improved operation with dynamic adaptation to the current scenario. The prime advantage being gained is the ability to seamlessly integrate ad-hoc wireless networks belonging to dissimilar organisations.