Search results for "mobile radio"
showing 10 items of 29 documents
Mobile Encounter Networks and Their Applications
2008
This article presents mobile encounter networks (MENs), which emerge when mobile devices come across each other and form a temporary connection between them using a common short-range radio technology. Local information exchanges between mobile devices results in a broadcast diffusion of information to other users of the network with a delay. Gasoline price comparison system (GPCS), which delivers newest gasoline prices to mobile users using mobile encounter information diffusion, is described as well as other application areas where MENs could be used. The feasibility of building MENs using bluetooth is tested with the BlueCheese mobile encounter network middleware and it is found that the…
Time dispersion characterization for UWB mobile radio channels between 3.1 and 10.6 GHz
2007
In this paper, a characterization of the UWB mobile radio channel time dispersion is presented. The results provided were obtained from a measurement campaign carried out in a typical indoor office scenario in the band from 3.1 to 10.6 GHz. Time dispersion metrics as delay spread, coherence bandwidth, delay interval and delay window, in both line-of-sight (LOS) and non-line-of-sight (NLOS) conditions are provided.
An improved iterative nonlinear least square approximation method for the design of measurement-based wideband mobile radio channel simulators
2011
This paper deals with the design of measurement-based simulation models for wideband single-input single-output (SISO) mobile radio channels. We present an improved version of the iterative nonlinear least square approximation (INLSA) method for computing the parameters of measurement-based simulation models. The proposed method aims to fit the temporal-frequency correlation function (TFCF) of the simulation model to that of the measured channel. Unlike the original INLSA method, the proposed approach provides a unique optimal set of estimated model parameters. The proposed iterative procedure involves numerical optimization techniques to determine a set of parameters that minimizes the Euc…
Using MANET Protocols in Wireless Sensor and Actor Networks
2008
Although there are several routing protocols for wireless sensor and actor networks (WSAN), none of them have became standard. Now, there are several standard protocols for mobile ad hoc networks (MANET) that have been developed for devices with higher computing features than the sensor nodes. On the other hand, one of the main characteristics of the MANET protocols is their scalability. In this paper, we show the performance of a WSAN, when MANET protocols are used, for several topologies. We will discuss and evaluate which standard protocol is the best one depending on the number of nodes in the topology and depending on their mobility. Finally we will show their comparison. As far as we …
A MANET Autoconfiguration System based on Bluetooth Technology
2006
The availability of both Wi-Fi and Bluetooth technologies on currently available devices offers the possibility to combine both in order to make the most out of their capabilities. In this paper we propose using Bluetooth technology to solve the configuration problem of the terminals conforming an IEEE 802.11-based ad-hoc network. The main objective of mobile ad- hoc networks (MANETs) is to extend the connectivity range of nodes through packet forwarding, thereby avoiding the use of a fixed infrastructure. However, since configuration of nodes is a complex issue, we provide a fast and reliable solution to auto-configure MANET terminals. Our solution is adequate for the quick setup and deplo…
Streaming for vehicular users via elastic proxy buffer management
2004
In this article we refer to the market of vehicular networks, where groups of customers located in the same public vehicle (e.g., a train or bus) connect to a terrestrial network through a wireless/satellite backbone link. Elastic buffering is a proxy management technique devised to decouple the multimedia information retrieval rate on the network backbone from the playout streaming rate at the user terminal. It has been shown in the past that the application of elastic buffering mechanisms in terrestrial networks brings significant advantages in terms of network effectiveness. We show that elastic buffering is an extremely effective means to reduce, or even eliminate, streaming service out…
Complete Shadowing Modeling and its Effect on System Level Performance Evaluation
2008
Computer simulations are a common procedure for assessing the performance of new algorithms. To conduct a valid and accurate study, the models employed in such simulators need to be carefully selected. Regarding shadowing modeling, one-dimensional models are fairly commonplace in the literature. While simple and with low computational costs, these models can not produce correlated fading values for mobiles that are in nearby positions and, besides, do not include the cross-correlation effect. To overcome these limitations, this paper presents a bi-dimensional shadowing model which introduces both the spatial correlation and the cross-correlation present in real systems. Finally, the impact …
Improved support for streaming services in vehicular networks
2004
This paper presents a resource management mechanism aimed at improving the effectiveness of streaming services in vehicular networks. The scenario considered in this paper is that of a group of customers located into a same public vehicle, e.g. a moving train connected to the network via a satellite link, and requesting either video-on-demand-like services, as well as real-time diffusive (broadcast) streaming services. We show that a proxy server, devised to introduce an elastic buffer aimed at decoupling the information retrieval download speed on the outer network from the natural play-out speed used in the vehicular network, results to be an extremely effective approach in reducing the o…
Level-Crossing Rate and Average Duration of Fades of the Envelope of Mobile-to-Mobile Fading Channels in Cooperative Networks Under Line-of-Sight Con…
2008
This paper studies the fading behavior of mobile- to-mobile (M2M) fading channels in relay-based cooperative networks under line-of-sight (LOS) conditions. Here, we assume that LOS components exist in both the direct link between the source mobile station (SMS) and the destination mobile station (DMS) as well as in the link via the mobile relay (MR). In such a propagation environment, the fading channel is referred to as the multiple-LOS second-order scattering (MLSS) channel. The fading behavior of MLSS channels is studied by analyzing the level-crossing rate (LCR) and the average duration of fades (ADF) of the received envelope. We have derived analytical expressions for the LCR, ADF, and…