Stefano Lucetti

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The increased popularity and the growth in the number of deployed IEEE 802.11 Access Points (APs) have raised the opportunity to merge together various disjointed wireless LANs to form a unique wireless mesh network (WMN). In this architecture only few nodes, called Portals (MPPs), interface to the external world thanks to their bridging/gateway functions,(More)
The paper proposes an architecture for a scheduling algorithm to be integrated in IEEE 802.11 access points (AP), able to take into account, besides the transport service class required by the destination user, the channel quality experienced by the destination mobile station (STA). The relevance of this topic is due to the observation that when one or more(More)
Wireless systems based on the IEEE 802.11 standard are known to suffer a performance degradation when just a single station in the network experiences bad channel conditions toward the Access Point (AP). This phenomenon, known as the “performance anomaly”, is mainly due to the max-min throughput fairness of the CSMA/CA algorithm of the 802.11 MAC. The(More)
The work presents the analysis of the evaluation of the maximum goodput achievable in a IEEE 802.11 b basic set service (BSS) performed by means of theoretical, simulative and experimental approaches. With respect to previous works on this topic, the presented study focuses on the comparison of the results obtained using the different approaches,(More)
In the paper we introduce and evaluate the performance of the Deficit Transmission Time (DTT) scheduler, a centralized channel aware scheduling algorithm for IEEE 802.11 networks. The scheduler has been designed to face two inconveniences of 802.11: the performance anomaly and the “inter-flow blocking” problem. DTT splits outgoing frames into multiple(More)
802.11 WLANs suffer severe performance degradation as soon as at least one of the stations in the Basic Service Set (BSS) experiments unfavorable radio channel conditions. This degradation is due to a so-called anomaly which manifests when one or some of the stations adopt a reduced transmission data rate, as well as to the reduced efficiency of radio(More)
The work presents the simulation analysis aimed at evaluating the admission region of a IEEE 802.11 e draft 4.0 standard, adopting the EDCF (enhanced distributed coordination function) access control mechanism. In particular, the study gives an estimate of the number of QoS aware services, namely videoconference and voice over IP (VoIP), that can be(More)
In this paper we describe a time-based admission control scheme for Multimedia over IP services in wireless LANs based on the IEEE 802.11e standard. We build on an existing work where it was defined a parameter, called Network Utilization Characteristic (NUC), to measure the temporal occupancy of the wireless channel of an IEEE 802.11 network. The work we(More)
This paper presents a simulation analysis for the evaluation of the admission region of a IEEE 802.11e network adopting the EDCA (Enhanced Distributed Channel Access) mechanism. In particular, this study gives an estimate of the number of QoS-aware applications, namely videoconference and Voice over IP (VoIP), that can be admitted to the transport service(More)