Search results for "IEEE"
showing 10 items of 135 documents
Integrated Fuzzy Solution for Network Selection using MIH in Heterogeneous Environment
2013
ISSN: 1942-2644; International audience; Seamless handover between networks in heterogeneous environment is essential to guarantee end-to- end QoS for mobile users. A key requirement is the ability to select seamlessly the next best network. Currently, the implementation of the selection algorithm of the IEEE 802.21 standard by National Institute of Standards and Technology considers only the signal strength as a parameter to select the best destination network. In this paper, we improve the implementation of the existing selection algorithm by proposing an integrated solution to select the best destination network. Our proposed solution consists of proposing a Multi Criteria Selection Algo…
IP-Based Mobility Management and Handover Latency Measurement in heterogeneous environments
2017
International audience; One serious concern in the ubiquitous networks is the seamless vertical handover management between different wireless technologies. To meet this challenge, many standardization organizations proposed different protocols at different layers of the protocol stack. The Internet Engineering Task Force (IETF) has different groups working on mobility at IP level in order to enhance mobile IPv4 and mobile IPv6 with different variants: HMIPv6 (Hierarchical Mobile IPv6), FMIPv6 (Fast Mobile IPv6) and PMIPv6 (Proxy Mobile IPv6) for seamless handover. Moreover, the IEEE 802.21 standard provides another framework for seamless handover. The 3GPP standard provides the Access Netw…
Handbook on Agent-Oriented Design Processes
2014
To deal with the flexible architectures and evolving functionalities of complex modern systems, the agent metaphor and agent-based computing are often the most appropriate software design approach. As a result, a broad range of special-purpose design processes has been developed in the last several years to tackle the challenges of these specific application domains. In this context, in early 2012 the IEEE-FIPA Design Process Documentation Template SC0097B was defined, which facilitates the representation of design processes and method fragments through the use of standardized templates, thus supporting the creation of easily sharable repositories and facilitating the composition of new des…
Improving IEEE 802.11 Performance in Chain Topologies through Distributed Polling and Network Coding
2009
Wireless multi-hop networks often rely on the use of IEEE 802.11 technology. Despite of the robustness of the IEEE 802.11 Distributed Coordination Function (DCF) for working in various network scenarios, it has been proven that critical inefficiencies can arise in the case of multi-hop packet forwarding. In this paper, we propose a MAC scheme, based on the virtualization of the Point Coordination Function, optimized for working on chain topologies with bidirectional traffic flows. Our scheme is based on a token-like access mechanism coupled with network coding. The basic idea is the use of multiple Point Coordinators (PCs) along the node chain, which are elected by passing special token fra…
Temporal Fairness Provisioning in Multi-Rate Contention-Based 802.11e WLANs
2005
The IEEE 802.11e extensions for QoS support in WLAN define the transmission opportunity (TXOP) concept, in order to limit the channel holding times of the contending stations in the presence of delay-sensitive traffic. We evaluate the use of TXOP for a different purpose: "temporal fairness" provisioning among stations employing different data rates. We show that the equalization of the channel access times allows each station to obtain its throughput basically (1) proportional to its transmission rate, and (2) independent of the transmitted frame length. This also improves the aggregate throughput of the overall WLAN. For a given TXOP limit, i.e., a granted channel access time, a station is…
Interference Estimation in IEEE 802.11 Networks
2010
This article describes a technique for distinguishing and quantifying medium access control (MAC) and physical layer (PHY) interference in error-prone 802.11 networks. This technique, is fully distributed, allowing each station to estimate interference individually. The estimator is based on an extended Kalman filter coupled to a mechanism for revealing abrupt changes in state. The network state is a vector of two components, representing PHY interference, expressed in terms of channel-error rate, and MAC interference. Two distinct state models are considered. When PHY interference can be assumed to be constant for all stations, network congestion is expressed by the number of competing ter…
Demo - Dynamic Adaptations of WiFi Channel Widths Without TX/RX Coordination
2017
Most modern standards for wireless communications support physical layer adaptations, in terms of dynamic selection of channel central frequency, transmission power, modulation format, etc., in order to increase link robustness under time-varying propagation and interference conditions. In this demo, we demonstrate that another powerful solution for extending physical layer flexibility in OFDM-based technologies is the dynamic adaptation of the channel width. Although some standards already define the possibility of utilizing multiple channel widths (e.g. 20MHz, 10MHz, 5MHz for IEEE 802.11a standards), such an utilization is limited to a static configuration of a value defined during the ne…
Side Effects of Ambient Noise Immunity Techniques on Outdoor IEEE 802.11 Deployments
2008
A very common conclusion of many experimental studies about IEEE 802.11 outdoor network deployments is that their poor performance results derive from the unfavorable interference and multi-path signals in which the WLAN-cards are required to operate. Goal of this paper is to show that this condition does not always hold, and unexpected and inaccurated PHY layer implementations can be a primary cause of packet losses. With the support of extensive measurement campaigns led in our campus, we provide the performance evidence that IEEE 802.11 outdoor performance impairments are strongly affected by proprietary interference mitigation techniques that adaptively adjust the WLAN-card receiver sen…
Earth resistance measurements in urban contexts: Problems and possible solutions
2017
Both EN 50522 and IEEE Std. 81 propose the Fall of Potential Method (FPM) to carry out the measurement of the resistance to earth of an Earthing System (ES). However, in urban areas, the recommended distances between the ES and auxiliary electrodes are not easy to respect, due to the presence of buildings and tarmac. Moreover, unknown buried metallic parts, as well as the interconnection among the ESs made by the Distributor System Operator, could modify the earth potential profile of the area, affecting the measurement results. In this paper, the issues that could affect the measurement result if FPM is used in an urban context are presented. A parametric analysis, carried out with Comsol …
IEEE Std. 1459 power quantities ratio approaches for simplified harmonic emissions assessment
2018
The paper investigates the suitability of using power ratio parameters for harmonic emissions assessment at the point of common coupling (PCC). The study is carried out starting from the IEEE Std. 1459-2010 apparent power decomposition, where power factors are defined for evaluating line utilization and harmonic pollution levels. In addition, the study investigates the behavior of new parameters, which are expressed in terms of ratio between IEEE Std. 1459-2010 power quantities. The study is carried out for both single-phase and three-phase case, also considering the presence of capacitors. ? 2018 IEEE.