Comunicação cooperativa em redes móveis ad hoc consciente em energia e atraso fim-a-fim

Monografia (graduação)—Universidade de Brasília, Faculdade de Tecnologia, 2014.O presente trabalho considera a utilização de técnicas de comunicação cooperativa em ambientes sem fio ad hoc como alternativa para aumentar a conectividade e, ao mesmo tempo, para reduzir o atraso e aumentar a eficiência energética das rotas para um sorvedouro. Neste contexto, são desenvolvidas duas novas técnicas: Cooperative Sink Communication (CSC) e Cooperative Sink Communication - Helper Set (CSC-HS). O CSC utiliza comunicação cooperativa para aumentar a conectividade entre os nós sensores e o nó sorvedouro e controle de topologia para diminuir o atraso fim-a-fim entre estes nós. A técnica CSC-HS utiliza comunicação cooperativa e controle de topologia para aumentar a conectividade e diminuir o atraso fim-a-fim mantendo a eficiência energética em redes ad hoc utilizando como métrica a quantidade de nós auxiliares que compõem a aresta cooperativa. Num primeiro momento, foi feita uma revisão teórica dos principais conceitos relativos ao entendimento deste trabalho: redes ad hoc, modelos de propagação em ambientes sem fio e vazão máxima teórica de redes ad hoc. Em um segundo momento, são apresentados os conceitos de comunicação cooperativa e é feita uma revisão bibliográfica sobre controle de topologia em redes ad hoc. Em seguida, as duas novas técnicas são propostas e são avaliadas por meio de comparação com outras técnicas da literatura e métricas definidas no escopo deste trabalho. O CSC, comparado com alternativas semelhantes, permite reduzir o atraso em até 50% nos cenários avaliados, enquanto o CSC-HS permite reduzir o atraso em até 45% mantendo uma eficiência energética por rota próxima de outras técnicas da literatura. _______________________________________________________________________________ ABSTRACTThis work considers the use of cooperative communication technique in mobile ad hoc networks as an alternative to increase connectivity and, simultaneously, reduce the delay and increase the energy efficiency of routes to a sink. In this context, two new techniques are developed: Cooperative Sink Communication (CSC) and Cooperative Sink Communication - Helper Set (CSC-HS). The CSC uses cooperative communication to increase connectivity between the sensor nodes and the sink node and topology control to reduce the end-to-end delay. CSC -HS technique uses cooperative communication and topology control to increase connectivity and reduce the delay by maintaining end-to-end energy efficiency in mobile ad hoc networks using as metric the number of helper nodes that compose the cooperative edge. At first, the main concepts of this work are briefly summarized: mobile ad hoc networks, propagation models and theoretical maximum throughput. In a second moment, the concepts of cooperative communications are presented and previous works in topology control in mobile ad hoc networks are reviewed. Then the two new techniques are proposed and evaluated by means of comparison with other techniques in the literature and metrics defined in this work. The CSC, compared to similar alternatives, can reduce delay by up to 50% in the evaluated scenarios, while the CSC -HS reduces delay by up to 45% maintaining the energy efficiency per route close to other techniques

Mobile ad hoc networks for intelligent systems

Advances in wireless technology and portable computing along with demands for high user mobility have provided a major promotion toward the development of ad hoc networks. Mobile ad hoc networks feature dynamic topology, self-organization, limited bandwidth and battery power of a node. They do not rely on specialized routers for path discovery and traffic routing. Research on ad hoc networks has been extensively investigated in the past few years and related work has focused on many of the layers of the communications architecture. This research intends to investigate applications of MANET for intelligent systems, including intelligent transportation system (ITS), sensor network and mobile intelligent robot network, and propose some approaches to topology management, link layer multiple access and routing algorithms. Their performance is evaluated by theoretical analysis and off-the-shelf simulation tools. Most current research on ad hoc networks assumes the availability of IEEE 802.11. However, the RTS/CTS protocol of 802.11 still leads to packet collision which in turn decreases the network throughput and lifetime. For sensor networks, sensors are mostly battery operated. Hence, resolving packet collision may improve network lifetime by saving valuable power. Using space and network diversity combination, this work proposes a new packet separation approach to packet collision caused by masked nodes. Inter-vehicle communication is a key component of ITS and it is also called vehicular ad hoc network. VANET has many features different from regular MANETs in terms of mobility, network size and connectivity. Given rapid topology changes and network partitioning, this work studies how to organize the numerous vehicular nodes and establish message paths between any pair of vehicular nodes if they are not apart too far away. In urban areas, the inter-vehicle communication has different requirements and constraints than highway environments. The proposed position-based routing strategy for VANETs utilizes the traffic pattern in city environments. Packets are forwarded based on traffic lights timing sequence and the moving direction of relaying vehicles. A multicast protocol is also introduced to visualize the real time road traffic with customized scale. Only vehicles related to a source node\u27s planned trajectory will reply the query packet. The visualized real time traffic information therefore helps the driver make better decision in route planning when traffic congestion happens. Nowadays robots become more and more powerful and intelligent. They can take part in operations in a cooperative manner which makes distributed control necessary. Ad hoc robot communication network is still fresh field for researchers working on networking technology. This work investigates some key issues in robot ad hoc network and evaluate the challenges while establishing robot ad hoc networks

Adoption of vehicular ad hoc networking protocols by networked robots

This paper focuses on the utilization of wireless networking in the robotics domain. Many researchers have already equipped their robots with wireless communication capabilities, stimulated by the observation that multi-robot systems tend to have several advantages over their single-robot counterparts. Typically, this integration of wireless communication is tackled in a quite pragmatic manner, only a few authors presented novel Robotic Ad Hoc Network (RANET) protocols that were designed specifically with robotic use cases in mind. This is in sharp contrast with the domain of vehicular ad hoc networks (VANET). This observation is the starting point of this paper. If the results of previous efforts focusing on VANET protocols could be reused in the RANET domain, this could lead to rapid progress in the field of networked robots. To investigate this possibility, this paper provides a thorough overview of the related work in the domain of robotic and vehicular ad hoc networks. Based on this information, an exhaustive list of requirements is defined for both types. It is concluded that the most significant difference lies in the fact that VANET protocols are oriented towards low throughput messaging, while RANET protocols have to support high throughput media streaming as well. Although not always with equal importance, all other defined requirements are valid for both protocols. This leads to the conclusion that cross-fertilization between them is an appealing approach for future RANET research. To support such developments, this paper concludes with the definition of an appropriate working plan

On the Experimental Evaluation of Vehicular Networks: Issues, Requirements and Methodology Applied to a Real Use Case

One of the most challenging fields in vehicular communications has been the experimental assessment of protocols and novel technologies. Researchers usually tend to simulate vehicular scenarios and/or partially validate new contributions in the area by using constrained testbeds and carrying out minor tests. In this line, the present work reviews the issues that pioneers in the area of vehicular communications and, in general, in telematics, have to deal with if they want to perform a good evaluation campaign by real testing. The key needs for a good experimental evaluation is the use of proper software tools for gathering testing data, post-processing and generating relevant figures of merit and, finally, properly showing the most important results. For this reason, a key contribution of this paper is the presentation of an evaluation environment called AnaVANET, which covers the previous needs. By using this tool and presenting a reference case of study, a generic testing methodology is described and applied. This way, the usage of the IPv6 protocol over a vehicle-to-vehicle routing protocol, and supporting IETF-based network mobility, is tested at the same time the main features of the AnaVANET system are presented. This work contributes in laying the foundations for a proper experimental evaluation of vehicular networks and will be useful for many researchers in the area.Comment: in EAI Endorsed Transactions on Industrial Networks and Intelligent Systems, 201

Robotic Wireless Sensor Networks

In this chapter, we present a literature survey of an emerging, cutting-edge, and multi-disciplinary field of research at the intersection of Robotics and Wireless Sensor Networks (WSN) which we refer to as Robotic Wireless Sensor Networks (RWSN). We define a RWSN as an autonomous networked multi-robot system that aims to achieve certain sensing goals while meeting and maintaining certain communication performance requirements, through cooperative control, learning and adaptation. While both of the component areas, i.e., Robotics and WSN, are very well-known and well-explored, there exist a whole set of new opportunities and research directions at the intersection of these two fields which are relatively or even completely unexplored. One such example would be the use of a set of robotic routers to set up a temporary communication path between a sender and a receiver that uses the controlled mobility to the advantage of packet routing. We find that there exist only a limited number of articles to be directly categorized as RWSN related works whereas there exist a range of articles in the robotics and the WSN literature that are also relevant to this new field of research. To connect the dots, we first identify the core problems and research trends related to RWSN such as connectivity, localization, routing, and robust flow of information. Next, we classify the existing research on RWSN as well as the relevant state-of-the-arts from robotics and WSN community according to the problems and trends identified in the first step. Lastly, we analyze what is missing in the existing literature, and identify topics that require more research attention in the future