The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
As a routing algorithm defined in IEEE 802.15.5, server routing (SR) can attain the optimal routes between source and destination nodes. However, we found that it has the following two problems: (1) unicasting the Link State Registrations does not utilize the available topology information, and (2) the relay list of Route Formations includes redundant contents. To address these problems, we propose...
Wireless mesh networks have seen a real progress due to their implementation at a low cost. Thus, the planning of such networks presents many challenges for network operators. Our aim in this paper is to provide a new planning solution using a multi-objective optimization approach.
After more than a decade of research and standardization, Mobile Ad Hoc NETworks (MANET) are finding their place in real-world deployments, such as in community, tactical and vehicular networks. Becoming so present in ``\textit{the real world}" also means that MANETs, and the protocols operating them, are affronted with a more hostile environment, where misconfiguration, eavesdropping, and attacks...
Content access and downloading in vehicular environments is expected to heavily rely on the availability of roadside infrastructure. Although vehicle-to-vehicle communication is foreseen, data will mostly flow through roadside access points, or RSUs (RoadSide Units), which suffer from less connectivity problems. However, at least in the early stages of deployment, the RSU coverage will be spotty,...
Layered and cooperative elements such as femto-cells and relays can improve performance or energy efficiency in mobile networks; however, they consume energy per se and their durations in operational state must therefore be minimised. This paper investigates the use of relays in WiMAX network deployments and concentrates on the cost/revenue performance and energy efficiency trade-off in such cases...
In this paper we present an algorithm for the Maximum Lifetime Broadcast (MLB) problem, i.e. the problem of extending network lifetime when a series of broadcast operations is executed. The algorithm, called DLMCA, is localized (it uses only 2-hop information) and supports asymmetric edge costs, i.e. those scenarios where the cost of sending a message from a node u to node v might be different from...
Limited resources in Wireless Sensor Networks (WSNs) are the key concern that needs to be given a careful consideration when studying virtually any aspect of a sensor network. Therefore, energy demands and radio bandwidth utilization should be addressed, especially in one-to-many communication. To define the problem, this article presents and categorizes the most common WSN multicast procedures depending...
In this paper we compare the energy efficiency of different cooperative schemes by means of energy efficiency contours. We consider a three-nodes cooperative scenario, employing either the amplify-and-forward (AF) or the decode-and-forward (DF) protocol. In the case of the DF protocol we analyse the performance of both repetition coding (RC) and parallel coding (PC). Our analysis shows that the maximum...
While network coding can potentially provide significant throughput benefits by combining packets prior to forwarding them, the achievable gains are directly related to the coding opportunities at a relay that performs encoding. If the relay does not have packets destined for distinct destinations, that can be encoded together, the network coding gains could be marginal. Towards increasing the opportunities...
The increasing penetration of distributed generation (DG) in distribution systems has resulted in a challenge for the conventional protection methods, due to the bi-directional power flow and the variation of fault current contribution. Moreover, the operation of distribution system in islanded mode is still an issue due to the difference between the short circuit current in islanded mode and grid-connected...
Network coding is a promising technology that has been shown to improve throughput in wireless mesh networks. In this paper, we compare the analytical and experimental performance of COPE-style network coding in IEEE 802.11 ad-hoc networks. In the experiments, we use a lightweight scheme called CATWOMAN that can run on standard WiFi hardware. We present an analytical model to evaluate the performance...
Most topology control algorithms for wireless ad hoc networks strive to reduce energy consumption by creating a sparse topology with few long-distance links. However, in a sparse topology, the average path length is relatively large (increasing end-to-end delay), and the number of vertex-disjoint paths between source-destination pairs is relatively small (reducing fault-tolerance). Unlike traditional...
Overlay network architectures that use orthogonal channels have been known to provide effective additional resources to underlying networks in high demand. Overlays are composed of relay nodes provided with rich computational resources and multiple wireless interfaces that make them capable of establishing several non-interfering networks. These networks can be used to move traffic around in a non-interfering...
Body Area Networks (BANs), targeting everywhere anytime health monitoring, operate in license-exempt frequency bands. They require a cross layer design that jointly considers the requirements of (1) access delay to the medium and (2) packet delivery ratio (PDR). In this paper, we experimentally evaluate the PDR of a BAN under static and dynamic scheduling schemes. Investigations show that static multi-hop...
Advances in sensing and wireless communication technologies have enabled a wide spectrum of Outdoor Wireless Sensor Network (OWSN) applications. Some applications require the existence of a communication backbone federating different OWSN sectors, in order to collaborate in achieving more sophisticated missions. Federating (connecting) these sectors is an intricate task due to the huge distances between...
A fast, accurate fault location solution for power distribution feeders enables utility companies to clear a fault quicker and reduce the outage duration. Traditional impedance-based fault location methods assume that all feeder sections have the same impedance characteristics. This assumption introduces errors on feeders that have branches and line sections with different conductor types and tower...
In rescue operations, information acquisition from rescue personnel in the field is very crucial. Upcoming decision support systems also rely on information gathered in the field, like sensor data or video feeds. A condition for successful information sharing is a reliable communication network. During crisis, infrastructure networks are often unavailable or destroyed. Hence, personnel in the field...
The coupling of scale-free networks with mobile unstructured networks is certainly unusual. In mobile networks, connections active at a given instant are constrained by the geographical distribution of mobile nodes, and by the limited signal strength of the wireless technology employed to build the ad-hoc overlay. This is in contrast with the presence of hubs, typical of scale-free nets. However,...
MIL-STD-188-220, a typical Ad-Hoc protocol frequently used by the military, utilizes an FM radio to perform Relays. The function of the SDR (Source Directed Relay), which refers to the routing information table interchanged to the function of the Topology Update, sets up a path to reach a receiver. Due to the low speed interface of the FM radio, we designed a simulation employing OPNET to determine...
We have started production of an information and control network TC-net 1G on a commercial basis. TC-net 1G connects control devices at high speed in supervision and control systems, such as general industry and infrastructure systems. TC-net 1G, developed based on technologies of TC-net, has accelerated transmission performance to 1Gbps, enhanced surveillance of RAS (Reliability Availability Serviceability)...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.