Showing papers by "Antonio Iera published in 2005"
TL;DR: This work, dealing with architectural design options, takes into account many metrics relevant to aspects, such as: frequency allocation, costs in terms of resource utilization, signaling traffic load, number and location of customers, reliability, possible retransmission paths, user mobility, and QoS.
Abstract: New-generation telecommunications systems are expected to meet the rising user exigencies of mobility and ubiquitous access to multimedia services. As a consequence, 3GPP consortium has introduced the Multimedia Broadcast and Multicast Service (MBMS) concept into 3G/beyond-3G networks. Supporting MBMS in next generation hybrid wireless platforms becomes a challenging issue due to high traffic load deriving from both signaling message exchange and data transmission between multicast sources (BM-SC) and end users. Therefore, in this context, key research issues are surely: effective exploitation of the limited radio spectrums available, coordination of users accessing radio resources, as well as provisioning of desired QoS guarantees. Given the high mobility profiles typical of UMTS users, it clearly appears that the cited target performance can only be achieved through networking solutions based on an overlapped terrestrial-HAP-satellite coverage. An inter-working scenario where HAPs operate in synergy with the UMTS terrestrial and satellite segments seems to be the most promising solution to provide mobile users with MBMS services. Our work, dealing with architectural design options, takes into account many metrics relevant to aspects, such as: frequency allocation, costs in terms of resource utilization, signaling traffic load, number and location of customers, reliability, possible retransmission paths, user mobility, and QoS.
43 citations
TL;DR: The effects of augmenting the contention-based channel access mechanism of IEEE 802.11e through the assignment of dynamic traffic priorities, that adapt to either the application's quality requirements or the network congestion status are analyzed.
Abstract: Nowadays, research efforts are being put into the design of effective mechanisms to provide service quality differentiation in IEEE 802.11-based wireless LANs. In this article we analyze the effects of augmenting the contention-based channel access mechanism of IEEE 802.11e through the assignment of dynamic traffic priorities, that adapt to either the application's quality requirements or the network congestion status. The aim is to show the effectiveness and robustness of the proposed dynamic mechanism in a wireless ad hoc network, in both single-hop and multihop scenarios, under variable traffic and network load conditions.
40 citations
TL;DR: The prospects of an efficient interaction between UMTS and 802.11-based networks are analysed and a picture of the current standardisation activities in this field is given to enable the reader to better understand what has been done and what can still be done towards an efficient joint exploitation of both technologies.
40 citations
TL;DR: The algorithm proposed is specifically tailored to “dynamically” assign 802.11e MAC priorities, depending on both application QoS requirements and observed network congestion conditions, and is carefully designed, implemented into a system simulation tool, and its highly effective behaviour assessed under variable traffic and system conditions.
Abstract: Supporting real-time and interactive traffic in addition to traditional data traffic with a best-effort nature represents a constantly rising need in any kind of telecommunications environment. The IEEE 802.11 based WLAN (Wireless Local Area Network) environment does not represent an exception. This is why at different protocol layers, and primarily at the MAC layer, many efforts are being put by both the research community and the standardization bodies to design effective mechanisms for user QoS (Quality of Service) differentiation. Although early results are coming into sight, such as, for example, the IEEE 802.11e standard release, still a thorough research activity is required. Aim of the present paper is to contribute to the cited research issue by proposing an improvement to the "static" traffic prioritisation mechanism foreseen by the IEEE 802.11e MAC (Medium Access Control) protocol. This latter shows a twofold drawback. First, there is no certainty that QoS requirements relevant to a given application are always fulfilled by the "statically" associated priority. Second, resource requests of the applications are not adapted to the (usually highly) variable traffic conditions of a distributed WLAN environment. The algorithm we propose is specifically tailored to "dynamically" assign 802.11e MAC priorities, depending on both application QoS requirements and observed network congestion conditions. It is carefully designed, implemented into a system simulation tool, and its highly effective behaviour assessed under variable traffic and system conditions.
19 citations
05 Mar 2005
TL;DR: An overview of the WAVE mission payload architecture is presented and the major parameters of the payload architecture are discussed in addition to the different requirements and specifications of the on-board transmission and reception components and their dependence on the host platform.
Abstract: In this paper, an overview of the WAVE mission payload architecture is presented. WAVE (W-band Analysis and VErification) is the new project funded by the Italian Space Agency (ASI). The aim is to design and develop a W-band geostationary (GEO) payload to be deployed for scientific experimental studies of the W-band channel and possible utilization in satellite data communications. The large bandwidth availability in the W-band range allows conceiving and proposing advanced services for future scenarios in order to meet high-quality requirements for a large number of users. The major parameters of the payload architecture are discussed in addition to the different requirements and specifications of the on-board transmission and reception components and their dependence on the host platform
15 citations
01 Jan 2005
TL;DR: The focus is on the IEEE 802.11e MAC protocol that is proposed to enhance by introducing a mechanism to "dynamically" assign priorities to traffic, to satisfy throughput requirements of each class of traffic.
Abstract: This paper contributes to the issue of QoS differentiation in wireless ad hoc networks. The focus is on the IEEE 802.11e MAC protocol that we propose to enhance by introducing a mechanism to "dynamically" assign priorities to traffic. Priorities are hop-by-hop assigned according to network resource availability and load in order to satisfy throughput requirements of each class of traffic
9 citations
16 May 2005
TL;DR: It is shown how the introduced dynamicity is able to improve performance of the enhanced distributed channel access (EDCA) of IEEE 802.11e networks.
Abstract: In wireless LANs, QoS provisioning and multimedia traffic support are critical elements for the successful deployment of such networks. In this paper, we propose a dynamic mechanism to adapt data rate and priority of multimedia wireless stations equipped with IEEE 802.11e network cards. We show how the introduced dynamicity is able to improve performance of the enhanced distributed channel access (EDCA) of IEEE 802.11e networks.
8 citations
11 Sep 2005
TL;DR: A definition of a situation and location aware mechanism for QoS management and resource allocation is proposed by approaching the issue at a middleware layer in such a way as to make the underlying heterogeneous system completely transparent to the mobile user roaming across its segments.
Abstract: In this paper a novel concept of "situation and location" based quality of service (QoS) control for next generation hybrid wireless system is investigated. A brief overview of the evolutionary paths involving the QoS concept is given and the new vision of I-centric telecommunications scenario is addressed. In such a context, a definition of a situation and location aware mechanism for QoS management and resource allocation is proposed by approaching the issue at a middleware layer in such a way as to make the underlying heterogeneous system completely transparent to the mobile user roaming across its segments
8 citations
TL;DR: The main results of a performance evaluation study in UMTS environment, aiming at comparing X-MAQoS with alternative agent-based approaches for handling user access to telecommunications networks, are reported.
Abstract: In this paper we propose X-MAQoS, a novel XML-based multi-agent system for the QoS management in telecommunications networks. This system is characterized by the following features: (i) it handles a user profile and exploits it jointly with suitable network resource management techniques to maximize user satisfaction; (ii) it is capable of operating in a large variety of telecommunications networks; (iii) it is semi-automatic; (iv) it exploits XML for guaranteeing a light, versatile and standard mechanism for information representation, storing and exchange. In this paper the basic features of the system are discussed in details. Furthermore, the main results of a performance evaluation study in UMTS environment, aiming at comparing X-MAQoS with alternative agent-based approaches for handling user access to telecommunications networks, are reported.
4 citations
TL;DR: It is demonstrated here that dedicated access, despite rational appearances, allows 50% saving of signalling bandwidth while satisfying both the system and user constraints in terms of grade and quality of service respectively.
Abstract: The deployment of highly powerful and sophisticated new-generation satellite broadband systems implies that a large portion of their bandwidth on the radio interface has to be devoted to conveying signalling information. Adequately dimensioning such a signalling bandwidth is an important design objective allowing the effective exploitation of the overall system resources and the cost-effective provision of a target quality of service to multimedia traffic. The performance of two basic techniques for accessing the signalling channels in a reference multimedia geostationary platform is investigated in this paper: random (slotted Aloha) and dedicated access. It is demonstrated here that dedicated access, despite rational appearances, allows 50% saving of signalling bandwidth while satisfying both the system and user constraints in terms of grade and quality of service respectively. This is accomplished by providing a statistical centralized connection admission control on Earth and an intelligent scheduling of the resource requests on board the satellite.
3 citations
11 Sep 2005
TL;DR: This study is intended as a research contribution to the understanding of the actual usefulness of introducing a HAP stratum into terrestrial-satellite hybrid wireless systems.
Abstract: Multi-layered networks exploiting HAP and satellite segments are becoming a very attractive solution to deploy global telecommunication infrastructures. In fact, they can help in offering users ubiquitous access to multimedia information in an efficient and cost-effective way. In this paper a multi-layered infrastructure is presented aiming at efficiently allocating bandwidth among different user typologies. Two different scenarios are considered for DVB-RCS service delivery. A one-layer system, with the satellite coverage stratum only, and a two-layer one, with an integrated HAP-satellite coverage layer. A simulation campaign is conducted in order to assess the performance of both scenarios and to compare their performance. This study is, therefore, intended as a research contribution to the understanding of the actual usefulness of introducing a HAP stratum into terrestrial-satellite hybrid wireless systems