Search results for "Wireless network"
showing 10 items of 163 documents
A New Neighbour Selection Strategy for Group-Based Wireless Sensor Networks
2008
In any type of networks a neighbour selection method is needed to form the topology of the network and to know which node the information has to be sent to reach a destination. Nowadays, several selection strategies exist that are based on different aspects and mainly designed to work in common networks. In this paper we will show our study about those different methods and, then we show the development of a suitable neighbour selection strategy for group-based wireless sensor networks (WSN) that is based on a capacity parameter defined by us and the new neighbour distance. We also present the proposal architecture for WSNs and the protocol when a new node joins a group and has to select it…
A survey of wireless data center networks
2015
Data centers are becoming more and more popular for a wide variety of applications. However, the efficiency of data centers are restricted by many issues like cabling and maintenance problems in addition to performance problems like oversubscription. Wireless technology was proposed as it has the capability and the flexibility to offer feasible approaches to solve some of these problems. In this paper, we conduct a deep investigation about wireless data center networks, describe some works that enhance the performance of the network, then give some remarks and critiques. 2015 IEEE. Scopus
WIDAR: Bistatic WI-fi Detection And Ranging for off-the-shelf devices
2013
The huge spread of wireless networks and the success of location-aware applications require novel indoor po- sitioning mechanisms based on existing technologies such as IEEE 802.11. Taking inspiration from the RADAR, we propose WIDAR: a bistatic WI-fi Detection And Ranging system for off- the-shelf devices. WIDAR implementation is based on the USRP2 platform and is able to locate 802.11 stations while they operate in existing legacy networks. No substitution or repositioning of the Access Points is necessary. WIDAR works passively and does not expect any dedicated action from the target WiFi node. No airtime is wasted and the target cannot even detect that it is being ranged. Such features …
Supporting scalable video transmission in MANETs through distributed admission control mechanisms
2009
Emerging multimedia applications over mobile devices are becoming very popular, especially over infrastructure wireless networks such as cellular and WLANs. However, providing this kind of services over infrastructureless networks like ad hoc networks presents many additional problems. One of these problems is how to share resources fairly among the users involved. In this article we propose a QoS framework supporting scalable video streaming in mobile ad hoc networks based on distributed admission control and video traffic awareness. Our framework promotes fairness between video flows in terms of resource consumption. It also guarantees a significant reduction of the idle times experienced…
Measurement and Modeling of the Origins of Starvation of Congestion-Controlled Flows in Wireless Mesh Networks
2009
Significant progress has been made in understanding the behavior of TCP and congestion-controlled traffic over CSMA-based multihop wireless networks. Despite these advances, however, no prior work identified severe throughput imbalances in the basic scenario of mesh networks, in which a one-hop flow contends with a two-hop flow for gateway access. In this paper, we demonstrate via real network measurements, testbed experiments, and an analytical model that starvation exists in such a scenario; i.e., the one-hop flow receives most of the bandwidth, while the two-hop flow starves. Our analytical model yields a solution consisting of a simple contention window policy that can be implemented vi…
Supporting a Pseudo-TDMA Access Scheme in Mesh Wireless Networks
2013
Wireless mesh networks appear a promising solution for pro- viding ubiquitous low-cost wireless access, but cannot rely on simple CSMA access protocols because of the critical inefficiencies that arise in topologies with hidden nodes. To overcome these limitations, some important protocol extensions based on synchronization and reservation mechanisms have been ratified. In this paper we show that an alternative approach to the standardiza- tion of new features and signaling messages for mesh networks can be the utilization of programmable nodes able to execute different MAC protocols programmed on the fly. Signaling messages are used only for disseminating the new protocol among the nodes. …
A Wireless Mesh Network-based System for Hotspots Deployment and Management
2007
In recent years Wireless Local Area Networks (WLANs) or hotspots, as they are commonly known, have emerged as a promising networking platform to extend network connectivity in public venues, providing local coverage for Internet applications on the move in urban areas and rural environments. Wireless hotspots using 802.11-based technology have popped up in corporate offices, coffeehouses, airports, restaurants and bookstores worldwide. For all their utility and ease of use the 802.11 wireless protocol, known as WiFi, has become the mobile connectivity mechanism of choice for business people, travelers, villagers, and everyone else. Unfortunately, even with the protocol's ease of use and its…
An automatic cooperative retransmission MAC protocol in Wireless Local Area Networks
2009
Existing solutions for cooperation in wireless networks either require simultaneous transmission of source and relay nodes or impose major modifications to original MAC protocols. In this paper, a new efficient retransmission MAC protocol is proposed for IEEE 802.11 based cooperation communications, with minimum modifications to the DCF scheme. Throughput and access delay performance of the proposed protocols is analyzed in error-prone and highly temporally correlated channels. Numerical results show that significant benefits can be achieved with our cooperative protocol, compared with the legacy schemes.
Experimental characterization and mitigation of turbulence induced signal fades within an ad hoc FSO network
2014
Optical beams propagating through the turbulent atmospheric channel suffer from both the attenuation and phase distortion. Since future wireless networks are envisaged to be deployed in the ad hoc mesh topology, this paper presents the experimental laboratory characterization of mitigation of turbulence induced signal fades for two ad hoc scenarios. Results from measurements of the thermal structure constant along the propagation channels, changes of the coherence lengths for different turbulence regimes and the eye diagrams for partially correlated turbulences in free space optical channels are discussed. Based on these results future deployment of optical ad hoc networks can be more strai…
Significance of channel failures on network performance in CRNs with reserved spectrum
2016
It is well understood that in wireless networks, channel failures, which are typically caused by equipment or power failures as well as intrinsic features in radio transmissions, such as fading and shadowing, can easily result in network performance degradation. Therefore, fast recovery from channel failures is an important measure that should be incorporated with those networks. Consequently, in a cognitive radio network (CRN), channel failures can cause significant performance degradation in both primary and secondary networks. Instead, retainability, i.e., the capability of providing continuous connection for users must be guaranteed even if a significant network element is disrupted. In…