Search results for " protocol"
showing 10 items of 1320 documents
A new way of achieving multi-path routing in wireless networks
2020
In the 21st century, the wireless technology is still developing rapidly and trying to be 'Faster, Higher, and Stronger': faster data rate, higher bandwidth and stronger connectivity. Wireless Mesh Networks (WMN) have been envisioned as an important solution to the next generation wireless networking which can be used in wireless community networks, wireless enterprise networks, transportation systems, home networking and last-mile wireless internet access. They also provide a cheap, quick and effective way for building wireless data networks. Considering the nature of these networks, routing is a key process for operating the WMN. This paper proposes a new way of creating multi-path routin…
Performance Analysis in Spatially Correlated IEEE 802.11 Networks
2012
Wireless mesh networks are difficult to be characterized, especially under multi-hop traffic streams. The problem is that the local view of the channel and the correlation between the buffers of consecutive nodes in a stream path make complicated the identification of the contention level perceived by each station along the time. Such a figure is used in the models based on the so called decoupling assumption for evaluating the final scheduling of simultaneous channel access grants. In this paper we propose a simplified mesh network model focused on capturing the correlation due to the network topology and traffic routes rather than the access protocol state at each node. To this purpose, w…
An adaptive timer for RPL to handle mobility in wireless sensor networks
2016
This paper focuses on the performance of wireless sensor networks characterized by a hybrid topology composed of mobile and static sensor nodes. The Routing Protocol for Low power and lossy networks (RPL), which is standardized as an IPv6 routing protocol for low power and lossy networks, uses the trickle timer algorithm to handle changes in the network topology. However, this algorithm is not well adapted to dynamic environments. This paper enhances the trickle timer in order to fit with mobility requirements. Most of previous works have improved this algorithm without considering the random movement of nodes. In this work, the proposed timer algorithm takes into consideration the random t…
Throughput and energy efficiency comparison of one-hop, two-hop, virtual relay and cooperative retransmission schemes
2010
Two main types of approaches exist for implementing cooperative communications at the MAC layer: virtual-hop relay and cooperative retransmission. While the virtual-hop relay schemes employ relay nodes to forward packets when higher end-to-end throughput can be achieved compared with the direct transmission, the cooperative retransmission schemes use relays to retransmit data only after the direct transmission fails. However, the performance of the these different approaches has not been compared in the literature, especially when energy efficiency is considered. In order to find out the best transmission scheme, this paper evaluates and compares the performance of the one-hop direct transm…
Latency factor in worldwide IP routed networks
2014
Current Border Gateway Protocol (BGP) serves for worldwide internet backbone connections between different Autonomous Systems (AS) on the routing level. Continuously in real-time changing environment core routers calculate routing decisions based on path-vector database entries. AS path-vector database may contain multiple paths for various Internet Protocol (IP) prefix destinations where smallest entity in the path-vector is AS. In real world AS can be internet service operator, university or any other organization willing to participate in internet network via multi-homed uplinks. Unfortunately, internal part of AS is hidden in path-vector database thus excluding factors like latency, pac…
Broadband Internet Access via Multi-Hop Wireless Mesh Networks: Design, Protocol and Experiments
2010
Published version of an article from the journal: Wireless Personal Communications. The original publication is available at Spingerlink. http://dx.doi.org/10.1007/s11277-009-9907-9 While bandwidth for Internet access in urban areas is steadily increasing in recent years, many rural areas are still suffering from the effect of the digital divide. This paper presents a broadband Internet access paradigm developed in the context of the ADHOCSYS project, which was financed by the European Commission under the 6th Framework Program Information and Society Technologies, within the strategic objective of Broadband for All. Aiming at providing reliable Internet access in rural and mountainous regi…
A hybrid bio-inspired approach to solving the routing problem in mobile ad hoc networks
2018
A mobile ad hoc network (MANET) is an autonomous system of mobile hosts (nodes) connected by a wireless link. However, the problem of designing routing protocols poses challenges to researchers due to the unpredictable and dynamic nature of ad hoc networks. Hence, bio-inspired algorithms are widely used to design adaptive routing strategies for MANETs. This paper proposes a routing protocol based on the hybridisation of ant colony optimisation (ACO) and 2-opt heuristic with the optimisation of ACO parameters. Given the vast scope of the parameters, a genetic algorithm is used to minimise the complexity of the problem. The implementation of the method is realised by MATLAB. To valid the resu…
Small-diameter titanium Grade IV and titanium-zirconium implants in edentulous mandibles: three-year results from a double-blind, randomized controll…
2015
OBJECTIVE: The aim of this study was to compare crestal bone-level changes, soft tissue parameters and implant success and survival between small-diameter implants made of titanium/zirconium (TiZr) alloy or of Grade IV titanium (Ti) in edentulous mandibles restored with removable overdentures. MATERIALS AND METHODS: This was a randomized, controlled, double-blind, split-mouth multicenter clinical trial. Patients with edentulous mandibles received two Straumann bone-level implants (diameter 3.3 mm), one of Ti Grade IV (control) and one of TiZr (test), in the interforaminal region. Implants were loaded after 6-8 weeks and removable Locator-retained overdentures were placed within 2 weeks of l…
Reliable Coverage with Circumferential WMSNs
2021
This work tackles the closed peripheral coverage issue. Such circumferential surveillance is essential in numerous realistic applications where the goal is to ensure rapid detection of any unauthorized entry/exit of the monitored area. To respond to these requirements, peripheral WMSNs can be rapidly deployed around areas of interest (e.g., temporary military camps, natural or nuclear disasters, etc.). While it seems simple, this solution raises two major challenging issues. First, checking whether the deployed peripheral WMSN forms a closed shape around the monitored region. That is, any object trying to leave or access this area must be instantaneously detected by at least one multimedia …
Simple and convenient remote photoplethysmography system for monitoring regional anesthesia effectiveness
2017
Simple and inexpensive remote photoplethysmography system for monitoring the effectiveness of regional anesthesia was developed and tested. The system involves surgical lamp as light source, compact video camera and computer with custom developed software. Data from eight patients were processed and the effectiveness of regional anesthesia was calculated. The results showed that the standard surgical lamp can be used as a light source together with camera for remote monitoring of regional anesthesia effectiveness.