Search results for "Bile"
showing 10 items of 2148 documents
Improving the performance of CAR systems based on mobile phones
2013
Collaborative Augmented Reality (CAR) systems allow multiple users to share a real work environment including computer-generated images in real time. Currently, the hardware features of most mobile phones makes them a natural platform for CAR systems. However, the wide variety of these hardware features can have important effects on the performance of the mobile CAR applications. This thesis proposes a performance characterization and improvement of CAR systems based on mobile phones. The research results, at the time of writing this paper, shows that a CAR system using mobile phones as clients and with a single server can support up to one thousand clients while providing interactive respo…
Mobile Search - Social Network Search Using Mobile Devices Demonstration
2008
Mobile search prototype demonstrates the possibilities of social network search in N800 mobile devices. Search is initiated from a N800 mobile device to search the contacts in mobile device's addressbook. The contacts can be other N800 mobile devices running mobile Web server or normal Web servers in the Internet with Drupal content management system. Mobile device users can select which of their personal information such as phone numbers, calendar data etc. to share via a mobile Web server. The proposed search mechanism has many benefits compared to centralized Web search engines like Google. The search can locate information which is not referenced anywhere and thus allows hidden or rare …
Radio network aspects
2006
Publisher Summary This chapter reviews the mobile radio access network reference scenarios (MORANS)—used to study the performance of the radio cellular networks related to UMTS and the methodologies for the radio network performance evaluation, including the theoretical connectivity models,. It discusses the techniques for radio network optimization such as the packet scheduling for cellular systems or system capacity maximization through the use of multiple antennas. . In order to perform system simulations, reference values for the main parameters characterizing a WCDMA network, are required. MORANS is used for the identification of such parameters. The parameters are classified in two gr…
Correlation-Based Cell Degradation Detection for Operational Fault Detection in Cellular Wireless Base-Stations
2013
The management and troubleshooting of faults in mobile radio networks are challenging as the complexity of radio networks is increasing. A proactive approach to system failures is needed to reduce the number of outages and to reduce the duration of outages in the operational network in order to meet operator’s requirements on network availability, robustness, coverage, capacity and service quality. Automation is needed to protect the operational expenses of t he network. Through a good performance of the network element and a low failure probability the network can operate more efficiently reducing the necessity for equipment investments. We present a new method that utilizes the correlatio…
A Delay-Centric Dynamic Resource Allocation Algorithm for Wireless Communication Systems Based on HNN
2008
This paper proposes a dynamic resource-allocation (DRA) algorithm for packet data services in wireless communication systems based on Hopfleld neural networks (HNNs). The resource-allocation algorithm assumes a delay-centric approach in that it maximizes resource utilization of the overall system while minimizing the packet delay. The real-time (RT) working capability of HNN hardware implementation means that a very powerful scheduling DRA algorithm can be obtained. A generic formulation of the algorithm is presented to establish the optimal bit rate allocation. In addition, some illustrative examples of this formulation are given, considering specific wireless communication systems, such a…
Testing the H.264 error-resilience on wireless ad-hoc networks
2004
The purpose of this paper is to provide a framework to tune and evaluate the performance of the H.264 codec in 802.11b wireless ad-hoc networks. The codec's error-resilience features are measured under stress conditions typical to these networks, and the most critical parameters are presented. We present solutions concerning the random packet loss problem and show how to quickly recover from packet loss bursts.
A space-division time-division multiple access scheme for high throughput provisioning in WLANs
2005
Directional antennas may dramatically increase the capacity of a Wireless LAN by allowing several stations to simultaneously communicate. Since deployment of directive/smart antennas on the customer's terminals is awkward (for technological, cost, robustness, and convenience reasons) it is of interest to deploy advanced antenna solutions only at the Access Point. When omnidirectional transmissions are used at the Mobile Stations, the asynchronous nature of the 802.11 MAC handshake structurally limits the possibility to exploit spatial reuse. Significant throughput enhancements can be achieved only at the expense of redesigning (part of) the 802.11 MAC protocol: mainly a form of synchronizat…
Modeling of Vehicle-to-Vehicle Channels in the Presence of Moving Scatterers
2012
In this paper, we derive a vehicle-to-vehicle~(V2V) channel model assuming a typical propagation scenario in which the local scatterers move with random velocities in random directions. The complex channel gain of the proposed V2V channel model is provided. Subsequently, for different scatterer velocity distributions, the corresponding autocorrelation functions~(ACFs) are derived, illustrated, and compared with the classical ACF derived under the assumption of fixed scatterers. Furthermore, under specific conditions, highly accurate approximations for the ACFs are provided in closed form. Since the proposed V2V channel model covers several communication scenarios as special cases, including…
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.