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

Routing Protocol Performance Evaluation for Mobile Ad-hoc Networks

Currently, MANETs are a very active area of research, due to their great potential to provide networking capabilities when it is not feasible to have a fixed infrastructure in place, or to provide a complement to the existing infrastructure. Routing in this kind of network is much more challenging than in conventional networks, due to its mobile nature and limited power and hardware resources. The most practical way to conduct routing studies of MANETs is by means of simulators such as GloMoSim. GloMoSim was utilized in this research to investigate various performance statistics and draw comparisons among different MANET routing protocols, namely AODV, LAR (augmenting DSR), FSR (also known as Fisheye), WRP, and Bellman-Ford (algorithm). The network application used was FTP, and the network traffic was generated with tcplib [Danzig91]. The performance statistics investigated were application bytes received, normalized application bytes received, routing control packets transmitted, and application byte delivery ratio. The scenarios tested consisted of an airborne application at a high (26.8 m/s) and a low speed (2.7 m/s) on a 2000 m x 2000 m domain for nodal values of 36, 49, 64, 81, and 100 nodes, and radio transmit power levels of 7.005, 8.589, and 10.527 dBm. Nodes were paired up in fixed client-server couples involving 10% and 25% of the nodes being V111 clients and the same quantity being servers. AODV and LAR showed a significant margin of performance advantage over the remaining protocols in the scenarios tested

Including context in a routing algorithm for the internet of things

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia InformáticaThe “Internet of Things” assumes that a large number of devices which are used on a daily basis will eventually become connected to the Internet. This scenario will provide room for a large set of new applications, however the network connections of an enormous set of nodes, which can be connected and disconnected, can move around and which have limitations with regards to their processing and communication capabilities, raises the need for the development of new message routing algorithms, different from those being in use today. In this thesis, a contribution is made towards the development of this type of algorithms. In particular, the idea which is tested is whether routing algorithms can improve their performance at various levels, such as, message delivery time, number of messages lost, power consumption, etc., if in the routing decisions these algorithms can make use of the concept of “Context”. Within the framework of this thesis, the “Context” is the organized collection of information which the routing algorithm collects from the environment surrounding the network nodes, and which allows it to make better routing decisions. This information can be related to low-level issues, such as, node location, power required to send a message, etc., as well as, with constraints related to the application, such as, message priority, maximum delivery time, etc. In order to evaluate this approach, this thesis proposes a routing algorithm called C-AODV. As the name suggests, it is based on the ADOV algorithm, however it is modified in several aspects; in particular, the possibility of using information collected from the context can be utilized to improve message routing. In order to test the proposed solution, several tests were performed on the NS-3 simulator which allowed the evaluation of the algorithm functionalities. The tests performed indicate that the proposed solution is valid

Recent Trends in Communication Networks

In recent years there has been many developments in communication technology. This has greatly enhanced the computing power of small handheld resource-constrained mobile devices. Different generations of communication technology have evolved. This had led to new research for communication of large volumes of data in different transmission media and the design of different communication protocols. Another direction of research concerns the secure and error-free communication between the sender and receiver despite the risk of the presence of an eavesdropper. For the communication requirement of a huge amount of multimedia streaming data, a lot of research has been carried out in the design of proper overlay networks. The book addresses new research techniques that have evolved to handle these challenges

Coverage and Connectivity in Three-Dimensional Networks

Most wireless terrestrial networks are designed based on the assumption that the nodes are deployed on a two-dimensional (2D) plane. However, this 2D assumption is not valid in underwater, atmospheric, or space communications. In fact, recent interest in underwater acoustic ad hoc and sensor networks hints at the need to understand how to design networks in 3D. Unfortunately, the design of 3D networks is surprisingly more difficult than the design of 2D networks. For example, proofs of Kelvin's conjecture and Kepler's conjecture required centuries of research to achieve breakthroughs, whereas their 2D counterparts are trivial to solve. In this paper, we consider the coverage and connectivity issues of 3D networks, where the goal is to find a node placement strategy with 100% sensing coverage of a 3D space, while minimizing the number of nodes required for surveillance. Our results indicate that the use of the Voronoi tessellation of 3D space to create truncated octahedral cells results in the best strategy. In this truncated octahedron placement strategy, the transmission range must be at least 1.7889 times the sensing range in order to maintain connectivity among nodes. If the transmission range is between 1.4142 and 1.7889 times the sensing range, then a hexagonal prism placement strategy or a rhombic dodecahedron placement strategy should be used. Although the required number of nodes in the hexagonal prism and the rhombic dodecahedron placement strategies is the same, this number is 43.25% higher than the number of nodes required by the truncated octahedron placement strategy. We verify by simulation that our placement strategies indeed guarantee ubiquitous coverage. We believe that our approach and our results presented in this paper could be used for extending the processes of 2D network design to 3D networks.Comment: To appear in ACM Mobicom 200

Remotely piloted aircraft systems and a wireless sensors network for radiological accidents

In critical radiological situations, the real time information that we could get from the disaster area becomes of great importance. However, communication systems could be affected after a radiological accident. The proposed network in this research consists of distributed sensors in charge of collecting radiological data and ground vehicles that are sent to the nuclear plant at the moment of the accident to sense environmental and radiological information. Afterwards, data would be analyzed in the control center. Collected data by sensors and ground vehicles would be delivered to a control center using Remotely Piloted Aircraft Systems (RPAS) as a message carrier. We analyze the pairwise contacts, as well as visiting times, data collection, capacity of the links, size of the transmission window of the sensors, and so forth. All this calculus was made analytically and compared via network simulations.Peer ReviewedPostprint (published version

Cross-layer aided energy-efficient routing design for ad hoc networks

In this treatise, we first review some basic routing protocols conceived for ad hoc networks, followed by some design examples of cross-layer operation aided routing protocols. Specifically, cross-layer operation across the PHYsical layer (PHY), the Data Link layer (DL) and even the NETwork layer (NET) is exemplified for improving the energy efficiency of the entire system. Moreover, the philosophy of Opportunistic Routing (OR) is reviewed for the sake of further reducing the system's energy dissipation with the aid of optimized Power Allocation (PA). The system's end-to-end throughput is also considered in the context of a design example