Search results for "Telecommunication"
showing 10 items of 1769 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…
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…
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…
5G Unlocks Its Power for Global Mobile Connectivity [Mobile Radio]
2020
A wideband multiple-cluster MIMO mobile-to-mobile channel model based on the geometrical street model
2008
In this paper, we extend the geometrical street multiple-input multiple-output (MIMO) mobile-to-mobile (M2M) channel model with respect to multiple clusters of scatterers as well as to frequency selectivity. The statistical properties of the proposed reference model are studied. Analytical solutions are provided for the three-dimensional (3D) space-time cross-correlation function (CCF), the temporal autocorrelation function (ACF), the 2D space CCF, and the frequency correlation function (FCF). The correlation properties are studied under the assumption of non-isotropic scattering conditions. The proposed reference model can be used as a starting point for the derivation of a wideband MIMO M…
BEP analysis of M-ary PSK modulation schemes over double Rice fading channels with EGC
2010
In this article, the performance of M-ary phase shift keying (PSK) modulation schemes over mobile-to-mobile (M2M) fading channels with equal gain combining (EGC) in cooperative networks is analyzed. Narrowband M2M fading channels under line-of-sight (LOS) propagation conditions are modeled as double Rice processes. A dual-hop amplify-and-forward relay network, where LOS components can exist in the transmission links between the source mobile station and the destination mobile station via K mobile relays, is studied. Here, the average bit error probability (BEP) is utilized to evaluate the performance of Mary PSK modulation schemes. A simple analytical approximation for the average BEP of M-…
MCMIPv6: Multicast Configuration-based Mobile IPv6 protocol
2010
International audience; Mobile IPv6 (MIPv6) and its basic extension for network mobility NEMO were initially designed to manage the mobility of device users and networks respectively while maintaining a permanent IP address. Nevertheless, the different MIPv6's experiments have shown many lacks in case of high mobility of nodes such as in vehicular networks. To overcome these lacks, many solutions have been proposed by the research community. The most famous ones are HMIPv6 and FMIPv6 tackling each a specific issue. On the one hand, FMIPv6 introduces a solution to effectively minimize the L2/L3 latency and avoid the packets losses during the handover procedure. On the other hand, HMIPv6 is e…
Network Connectivity and Area Coverage for UAV Fleet Mobility Model with Energy Constraint
2016
International audience; Our main focus through the present paper is on developing an original distributed mobility model for autonomous fleet of interconnected UAVs (Unmanned Aerial Vehicles) performing an area exploration mission. The UAVs, equipped with wireless ad-hoc capabilities, are required to optimally explore an area while maintaining connectivity with their neighboring UAVs and the base station. Because energy is a scarce resource, especially for UAVs, its wise management is quite beneficial for the network lifetime and mission success. Hence, the proposed mobility model, compared to other models in the literature, is the first to ever include the remaining energy level as decisio…
Formal Analysis and Model Checking of a Group Authentication Protocol by Scyther
2016
Scyther [1] is designed to check the security and vulnerabilities of security protocols. In this paper, we use Scyther to analyze two discrete logarithm problem (DLP) based group authentication protocols proposed in [2]. These two protocols are claimed to satisfy several security requirements, but only part of them have been checked because of the properties and limitations of Scyther. Some positive results have been gained and show that the protocols provide mutual authentication and implicit key authentication and are secure against impersonation attack. An important innovation in this paper is that we have extended the expressing ability of Scyther by giving some reasonable assumption du…