Wide Range Of Wireless Networks Research Articles

Circularly Polarized Parasitic Strips Loaded Broadband Printed Antenna for Sub-6 GHz (n77/n78/n79) Domain

A novel broadband circularly polarized compact antenna is designed with broad axial ratio bandwidth (ARBW) for Sub-6 GHz fifth-generation applications. The antenna is printed on a Duroid substrate (ϵr = 2.2, thickness of 0.8 mm). The proposed configuration consists of two diagonally opposite symmetric parasitic strips energized by the matched transmission line and supported by a defected ground plane on the other side. By utilizing two parasitic strips and DGS concepts, wideband bandwidth of 3.4 GHz (2–5.4 GHz) Simulated and 3-dB ARBW of 2.5 GHz (2.9–5.4 GHz) is achieved. The CP behavior of the proposed antenna is investigated and discussed in detail with the help of the surface current distribution plot and magnitude/phase vs frequency plot. Simulated findings are justified by the measured results. The suggested antenna's simple design and high AR bandwidth make it a promising option for a wide range of wireless networks.

Monitoring and warning system of a route based on roadside sensors in VANET

Abstract The implementation of vehicle communication systems requires the development of a communication protocol between vehicles. For the design and development of active safety systems, it is intended to develop autonomous systems to collect and analyze information related to the external environment of the vehicle (based on radar systems, video cameras, image processing, etc.); and design and implementation of systems that exchange information between traffic vehicles. Intelligent solutions across a wide range of wireless networks, from large cellular networks to home networks, are being deployed in the field of transportation. A problem with information management and transmission is observed in e WSNs (wireless sensor networks), which usually contain hundreds or even thousands of terminal nodes, which must transmit collected data or commands to a data repository. Creating a means of communication between vehicles and traffic control devices is essential, thus forming an ad hoc network of variable sizes. The so-formed network provides vehicle drivers with information on road conditions, traffic congestion, accidents, warnings, and can help optimize traffic. The paper addresses the issue of inter-vehicle communication by presenting a minimalistic approach, facilitating intervehicular communication through a WSN network, considering extra-urban traffic areas with a high degree of complexity and changing environment (altitude changes, dangerous curves, difficult road conditions).

On providing wormhole‐attack‐resistant localization using conflicting sets

AbstractWormhole attack is a severe attack that can be easily mounted on a wide range of wireless networks without compromising any cryptographic entity or network node. In the wormhole attack, an attacker sniffs packets at one point in the network and tunnels them through the wormhole link to another point. Such kind of attack can deteriorate the localization procedure in wireless sensor networks. In this paper, we first analyze the impacts of the wormhole attack on the localization procedure. Then, we propose a secure localization scheme against the wormhole attacks called SLAW including three phases: wormhole attack detection, neighboring locators differentiation, and secure localization. The main idea of the SLAW is to build a so‐called conflicting set for each locator based on the abnormalities during the message exchanges, which can be used to differentiate the dubious locators to achieve secure localization. We first consider the simplified system model in which there is no packet loss and all the nodes have the same transmission range. We further consider the general system model where the packet loss exists and different types of nodes have different transmission radii. We conduct the simulations to illustrate the effectiveness of the proposed secure localization scheme and compare it with the existing schemes under different network parameters. Copyright © 2014 John Wiley & Sons, Ltd.

Joint congestion control and distributed scheduling for throughput guarantees in wireless networks

We consider the problem of throughput-optimal cross-layer design of wireless networks. We propose a joint congestion control and scheduling algorithm that achieves a fraction 1/ d I ( G ) of the capacity region, where d I ( G ) depends on certain structural properties of the underlying connectivity graph G of the wireless network, and also on the type of interference constraints. For a wide range of wireless networks, d I ( G ) can be upper bounded by a constant, independent of the number of nodes in the network. The scheduling element of our algorithm is the maximal scheduling policy. Although this scheduling policy has been considered in several previous works, the challenges underlying its practical implementation in a fully distributed manner while accounting for necessary message exchanges have not been addressed in the literature. In this article, we propose two algorithms for the distributed implementation of the maximal scheduling policy accounting for message exchanges, and analytically show that they still can achieve the performance guarantee under the 1-hop and 2-hop interference models. We also evaluate the performance of our cross-layer solutions in more realistic network settings with imperfect synchronization under the Signal-to-Interference-Plus-Noise Ratio (SINR) interference model, and compare with the standard layered approaches such as TCP over IEEE 802.11b DCF networks.

On the Complexity of Scheduling in Wireless Networks

We consider the problem of throughput-optimal scheduling in wireless networks subject to interference constraints. We model the interference using a family of -hop interference models, under which no two links within a -hop distance can successfully transmit at the same time. For a given , we can obtain a throughput-optimal scheduling policy by solving the well-known maximum weighted matching problem. We show that for , the resulting problems are NP-Hard that cannot be approximated within a factor that grows polynomially with the number of nodes. Interestingly, for geometric unit-disk graphs that can be used to describe a wide range of wireless networks, the problems admit polynomial time approximation schemes within a factor arbitrarily close to 1. In these network settings, we also show that a simple greedy algorithm can provide a 49-approximation, and the maximal matching scheduling policy, which can be easily implemented in a distributed fashion, achieves a guaranteed fraction of the capacity region for "all ." The geometric constraints are crucial to obtain these throughput guarantees. These results are encouraging as they suggest that one can develop low-complexity distributed algorithms to achieve near-optimal throughput for a wide range of wireless networks.

Modeling and transceiver design for asymmetric UWB links with heterogeneous nodes

In recent years, Ultra-Wideband (UWB) technology has emerged as a promising physical layer candidate for a wide range of wireless networks, especially due to its low operation power level and coexistence ability with traditional wireless systems. However, none of these physical layer realizations has specified the compatible operation among them (see, e.g.,). Therefore, the effective interoperability between asymmetric UWB transceivers needs to be considered for ubiquitous wireless communications. In this paper, we investigate the transceiver design for asymmetric UWB links with a single transmitter and a single receiver. We consider factors that can lead to the asymmetry between UWB transmitters and receivers such as different numbers of signal bands and different pulse rates. Our analysis reveals the similarity between the asymmetric UWB links and the conventional multiantenna systems. Then, MIMO signal processing approaches can be readily applied to achieve the optimal design in terms of channel throughput or bit error rate (BER). Analysis and simulations corroborate the effectiveness of our transceiver designs.

Cooperative Mobile Positioning Based on Received Signal Strength

Mobile positioning using Received Signal Strength (RSS) measurements is regarded as a low cost solution which is applicable in a wide range of wireless networks. In this paper, we propose a cooperative RSS-based positioning algorithm, that relies on the promising idea of mobile to mobile communications in the next generation of cellular networks. Simulations performed in this paper indicate that utilizing the additional RSS data of the short range communications between Mobile Stations (MS's), enhances the accuracy of the traditional RSS-based positioning algorithms.