Anna Lina Ruscelli

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The IEEE 802.11e standard introduces Quality of Service support for wireless local area networks through two MAC functions: Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA). While the former provides prioritized contention-based access to the medium, the latter uses a parameterized contention-free polling scheme. Several(More)
—Quality of Service (QoS) provided by the IEEE 802.11e amendment and by the proposed HCF Controlled Channel Access (HCCA) reference scheduler is tailored for Constant Bit Rate traffic streams. Moreover the numerous alternative scheduling algorithms are not suitable to serve Variable Bit Rate (VBR) traffic streams with the required QoS and real-time(More)
This paper presents a new scheduling algorithm, the Wireless Constant Bandwidth Server (W-CBS) for the Access Points of an IEEE 802.11e wireless networks to support traffic streams with Quality of Service guarantees, in particular in the case of multimedia applications which present variable bit rate traffic. The performance of W-CBS is compared to that of(More)
IEEE 802.11e HCCA reference scheduler guarantees Quality of Service only for Constant Bit Rate traffic streams, whereas its assignment of scheduling parameters (transmission time TXOP and polling period) is too rigid to serve Variable Bit Rate (VBR) traffic. This paper presents a new scheduling algorithm, <i>Dynamic TXOP HCCA</i> (DTH). Its scheduling(More)
The IEEE 802.11e standard introduces Quality of Service (QoS) support for wireless local area networks and suggests how to design a tailored HCF Controlled Channel Access (HCCA) scheduler. However the reference scheduling algorithm is suitable to assure service guarantees only for Constant Bit Rate traffic streams, whereas shows its limits for Variable Bit(More)
IEEE 802.11 standard for wireless networks recently has been enhanced with IEEE 802.11e amendment to this protocol which introduces Quality of Service support. It provides differentiation mechanisms at the Medium Access Control layer, using two additional access functions: the Enhanced Distributed Channel Access (EDCA) function and the HCF Controlled(More)
IEEE 802.11 based WLANs have became popular, but they can only provide best effort services and so they are poorly suitable for multimedia applications. Recently IEEE 802.11e standard has been proposed to support quality of service. The new standard introduces a so-called Hybrid Coordination Function containing two medium access mechanisms: contention-based(More)
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