33 resultados para Wireless systems


Relevância:

60.00% 60.00%

Publicador:

Resumo:

 Security provisioning is an essential part in the design of any communication systems, which becomes more critical for wireless systems. The consideration and comparisons of security algorithms in various Open Systems Interconnection layers is a difficult task, because there are many performance metrics involved. The aim of this novel research article is to present research results for the design of a wireless system revolving around the practical and low-cost implementation of Suite-B algorithms in different layers. Suite-B, promulgated by the National Security Agency, is a set of cryptographic algorithms, including non-repudiation. The end results include the deployment of Suite-B algorithms at the application, transport, and network layers and the protocol flow at each layer.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

We investigate the resource-allocation problem in multicell networks targeting the max-min throughput of all cells. A joint optimization over power control, channel allocation, and user association is considered, and the problem is then formulated as a nonconvex mixed-integer nonlinear problem (MINLP). To solve this problem, we proposed an alternating-optimization-based algorithm, which applies branch-and-bound and simulated annealing in solving subproblems at each optimization step. We also demonstrate the convergence and efficiency of the proposed algorithms by thorough numerical experiments. The experimental results show that joint optimization over all resources outperforms the restricted optimization over individual resources significantly.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Security provisioning is an essential part in the design of any communication systems, which becomes more critical for wireless systems. Devising a quality of service (QoS) mechanism to coexist security algorithms is a daunting, yet inevitable task. The aim of this novel research article is to present a novel energy efficient, cross-layer-based application-layer wireless system with simultaneous security and QoS supports, which revolves around the practical and low-cost implementation of Suite-B cryptographic algorithms (promulgated by the National Security Agency) and detailed analyses of the associated complexities. The focus of this article is on the novel cross-layer mechanism and its effectiveness to handle QoS-enabled treatment while offering security enhancements.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Main challenges for a terminal implementation are efficient realization of the receiver, especially for channel estimation (CE) and equalization. In this paper, training based recursive least square (RLS) channel estimator technique is presented for a long term evolution (LTE) single carrier-frequency division multiple access (SC-FDMA) wireless communication system. This CE scheme uses adaptive RLS estimator which is able to update parameters of the estimator continuously, so that knowledge of channel and noise statistics are not required. Simulation results show that the RLS CE scheme with 500 Hz Doppler frequency has 3 dB better performances compared with 1.5 kHz Doppler frequency.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Advances in information and communications technology has led to a significant advances in noncontact portable devices capable of monitoring vital signals of patients. These wearable and implantable bio-monitoring systems allow collections of wearable sensors to be constructed as a Body Area Network (BAN) to record biological data for a subject. Such systems can be used to improve the quality of life and treatment outcomes for patients. One of the main uses for a bio-monitoring system is to record biological data values from a subject and provide them to a doctor or other medical professional. However, wearable bio-monitoring systems raise unique security considerations. In this paper, we discuss some of the security considerations that have arisen in our work around communications agnostic bio-monitoring, and how we have addressed these concerns. Furthermore, the issues related to the identifying and trusting sender and receiver entities are discussed.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Deployment of mobile technologies and applications in health care are becoming prevalent worldwide. As mobile innovation and standards in wireless continue to evolve, so does the mobile health care information systems framework. In this paper, we explore this evolving framework by synthesising current technologies, applications, issues and examining this through the actor-network theory (ANT) which seeks to understand socio-technical change by adopting a symmetric treatment of people and technologies.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Purpose – The purpose of this paper is to introduce a wireless web-based ordering system called iMenu in the restaurant industry. Design/methodology/approach – By using wireless devices such as personal digital assistants and WebPads, this system realizes the paradigm of pervasive computing at tableside. Detailed system requirements, design, implementation and evaluation of iMenu are presented.

Findings – The evaluation of iMenu shows it explicitly increases productivity of restaurant staff. It also has other desirable features such as integration, interoperation and scalability. Compared to traditional restaurant ordering process, by using this system customers get faster and better services, restaurant staff cooperate more efficiently with less working mistakes, and enterprise owners thus receive more business profits.

Originality/value – While many researchers have explored using wireless web-based information systems in different industries, this paper presents a system that employs wireless multi-tiered web-based architecture to build pervasive computing systems. Instead of discussing theoretical issues on pervasive computing, we focus on practical issues of developing a real system, such as choosing of web-based architecture, design of input methods in small screens, and response time in wireless web-based systems.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Wireless sensor networks represent a new generation of real-time  embedded systems with significantly different communication constraints from the traditional networked systems. With their development, a new attack called a path-based DoS (PDoS) attack has appeared. In a PDoS attack, an adversary, either inside or outside the network, overwhelms sensor nodes by flooding a multi-hop endto- end communication path with either replayed packets or injected spurious packets. In this article, we propose a solution using mobile agents which can detect PDoS attacks easily.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Wireless sensor networks represent a new generation of real-time embedded systems with significantly different communication constraints from the traditional networked systems. With their development, a new attack called a path-based DoS (PDoS) attack has appeared. In a PDoS attack, an adversary, either inside or outside the network, overwhelms sensor nodes by flooding a multi-hop end-to end communication path with either replayed packets or injected spurious packets. Detection and recovery from PDoS attacks have not been given much attention in the literature. In this article, we propose a solution using mobile agents which can detect PDoS attacks easily and efficiently and recover the compromised nodes.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In wireless mobile computing, location management is introduced whenever users move from one place to another. In order to track a mobile user, the system must store information about their current location and report new locations to a home base station. Numerous techniques have been proposed to optimally manage the location of mobile hosts in mobile networks. This paper attempts to present a more structured and comprehensive analysis of the current location management techniques architectures and their technology enablers. We discuss some of the principal issues involved in location management and present a taxonomy and survey of location management strategies that have been proposed in the literature over the years for mobile computing systems.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Optimizing energy consumption for extending the lifetime in wireless sensor networks is of dominant importance. Groups of autonomous robots and unmanned aerial vehicles (UAVs) acting as mobile data collectors are utilized to minimize the energy expenditure of the sensor nodes by approaching the sensors and collecting their buffers via single hop communication, rather than using multihop routing to forward the buffers to the base station. This paper models the sensor network and the mobile collectors as a system-of-systems, and defines all levels and types of interactions. A practical framework that facilitates deploying heterogeneous mobiles without prior knowledge about the sensor network is presented. Realizing the framework is done through simulation experiments and tested against several performance metrics.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Power control design is a critical aspect of CDMA cellular systems design. This paper develops an adaptive power controller design method for CDMA systems. The key to the power control design is on the recursive identification of the underlying wireless stochastic channel model parameters. The identification process guarantees the power controller to work well for systems in unknown or time varying network environment.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The next generation of wireless networks is envisioned as convergence of heterogeneous radio access networks. Since technologies are becoming more collaborative, a possible integration between IEEE 802.16 based network and previous generation of telecommunication systems (2G, ..., 3G) must be considered. A novel quality function based vertical handoff (VHO) algorithm, based on proposed velocity and average receive power estimation algorithms is discussed in this paper. The short-time Fourier analysis of received signal strength (RSS) is employed to obtain mobile speed and average received power estimates. Performance of quality function based VHO algorithm is evaluated by means of measure of quality of service (QoS). Simulation results show that proposed quality function, brings significant gains in QoS and more efficient use of resources can be achieved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Wireless sensor networks represent a new generation of real-time embedded systems with significantly different communication constraints from the traditional networked systems. With their development, a new attack called a path-based DoS (PDoS) attack has appeared. In a PDoS attack, an adversary, either inside or outside the network, overwhelms sensor nodes by flooding a multi-hop end-to-end communication path with either replayed packets or injected spurious packets. Detection and recovery from PDoS attacks have not been given much attention in the literature. In this article, we consider wireless sensor networks designed to collect and store data. In a path-based attack, both sensor nodes and the database containing collected data can be compromised. We propose a recovery method using mobile agents which can detect PDoS attacks easily and efficiently and recover the compromised nodes along with the database.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This paper presents a framework for indoor location prediction system using multiple wireless signals available freely in public or office spaces. We first propose an abstract architectural design for the system, outlining its key components and their functionalities. Different from existing works, such as robot indoor localization which requires as precise localization as possible, our work focuses on a higher grain: location prediction. Such a problem has a great implication in context-aware systems such as indoor navigation or smart self-managed mobile devices (e.g., battery management). Central to these systems is an effective method to perform location prediction under different constraints such as dealing with multiple wireless sources, effects of human body heats or mobility of the users. To this end, the second part of this pa- per presents a comparative and comprehensive study on different choices for modeling signals strengths and prediction methods under different condition settings. The results show that with simple, but effective modeling method, almost perfect prediction accuracy can be achieved in the static environment, and up to 85% in the presence of human movements. Finally, adopting the proposed framework we outline a fully developed system, named Marauder, that support user interface interaction and real-time voice-enabled location prediction.