1,720,976 research outputs found
Multimedia Messaging System (MMS)
No full textDue to the enormous success of GSM- SMS, new messaging types have been defined in order to enrich the exchanged contents. This chapter focuses on the evolution from SMS to Enhanced Messaging Service (EMS) to Multimedia Messaging Service (MMS).
It provides a detailed description of MMS service architecture and multimedia services
A WiMAX simulation module for investigating QoS during horizontal handovers
No full textWiMAX is one of the most interesting solutions for broadband wireless access, supporting multimedia traffic and applications through an appropriate QoS management for fixed and mobile devices. Simulation tools play a central role to study network performance and to test new functionalities. In this paper we propose a new simulation module, compliant to IEEE 802.16e, which implements the five WiMAX QoS classes and handover procedures as well, so as to support investigations on QoS management during mobility in WiMAX scenarios. The developed tool has been validated and tested through exhaustive simulations, showing its conformance with the defined specifications
A MAC Scheme for Integrating Video and Web Traffics in Future High-Quality Mobile Communication Networks"
No full textAn IoT Smart Environment in Support of Disease Diagnosis Decentralization
Full text linkThe percentage of seniors in the global population is constantly growing and solutions in the field of fall detection and early detection of neuro-degenerative pathologies have a crucial role in order to increase life expectancy and quality of life. This study aims to extend fall detection and effective recognition of early signs of diseases to new smart environments, conceiving the decentralization of diagnostic monitoring in everyday life activities in a more pervasive paradigm. Inspiring to research outcomes, in this work an architecture is designed to detect falls in crowded indoor environments during events/exhibitions, for favoring a timely and effective intervention. It also foresees a continue monitoring of the gait for seniors during the visit, thus extracting key features which are stored on a dedicated database. The proposed solution allows third party researchers to perform analysis on the obtained gait datasets, through the adoption of advanced data-mining techniques for the detection of early signs of neuro-degenerative diseases and other pathologies. The architecture designed here aims to provide a step forward concerning the extension of smart monitoring environments for the detection of falls and early signs of pathologies in everyday life, in a more pervasive and decentralized paradigm
Improving QoS Performance in IEEE 802.11e Under Heavy Traffic Loads
No full textIEEE 802.11e standard is a concrete attempt to QoS challenge, but when the volume of traffic flows increases, this approach is not sufficient. Several techniques have been developed to improve WLAN QoS performance, mainly introducing a trade-off between performance and standard compatibility. This work describes the techniques used to enhance EDCA efficiency by suitably regulating standard's parameters and it introduces an innovative algorithm, named Dynamic TXOP (DTXOP), capable of enhancing fairness between upstream and downstream resource allocation in Wi-Fi networks. Finally, after a brief review of admission control algorithms for QoS support under heavy traffic loads, a suitable admission control scheme is integrated with DTXOP as a possible solution for facing QoS degradation of active sources due to an excessive network load. The benefits obtained by integrating DTXOP and the proposed admission control policy are shown in terms of QoS enhancement and efficiency in resource allocation. © Springer Science+Business Media, LLC 2011
QoS enhancement with dynamic TXOP allocation in IEEE 802.11e
No full textThe transmission opportunity (TXOP) mechanism defined in the IEEE 802.11 e Hybrid Coordination Function (HCF) is not optimized to meet the QoS requirements of heterogeneous applications, since it is usually allocated by default according to the different Access Categories (AC). In this paper we propose a new algorithm, named DTXOP, for the dynamic assignment of the TXOP maximum duration at the Access Point (AP) of an IEEE 802.lie WLAN. DTXOP is periodically updated according to the current traffic conditions of each specific AC. Simulation experiments show that DTXOP allows to enhance delay and throughput performance and to maintain fairness between upstream and downstream channel access times
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