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2006 | Buch

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Wireless Systems and Network Architectures in Next Generation Internet

Second International Workshop of the EURO-NGI Network of Excellence, Villa Vigoni, Italy, July 13-15, 2005, Revised Selected Papers

herausgegeben von: Matteo Cesana, Luigi Fratta

Verlag: Springer Berlin Heidelberg

Buchreihe : Lecture Notes in Computer Science

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik" , Springer Professional "Wirtschaft"

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Inhaltsverzeichnis

Frontmatter

Introduction

Abstract

We are nowadays spectators of a deep and rapid change in the world of communications which is mainly driven by two factors: the evolution of wireless technology and the amazing success of IP based applications.

The offer of wireless technology is vast and always increasing both with different standards and proprietary solutions. In this scenario, the end user equipment is often geared with multiple wireless network interface and consequently one has the choice on which technology to use as a gateway for connectivity.

Matteo Cesana, Luigi Fratta

Wireless Connectivity Solutions: From Wireless LANs to Ad Hoc and Sensor Networks

Optimizing Routing Schemes for Fast Moving Users in MST-Based Networks

Abstract

With the currently emerging trials for best-effort internet solutions on trains, solutions are required for delivering multimedia services to fast moving users. Research has already been devoted to dimensioning Ethernet aggregation networks, taking user movement into account while neglecting the experienced network performance. This paper extends this design for resilient networks and aims at minimizing packet loss and packet reordering in the dimensioning and routing process. For deployment in an Ethernet network which supports Multiple Spanning Trees (MSTs), effective path aggregation methods are proposed for finding a minimal set of spanning trees and these are thoroughly evaluated for different scenarios. Moreover the spanning tree assignment problem with predefined backup conditions is studied.

Filip De Greve, Frederic Van Quickenborne, Filip De Turck, Ingrid Moerman, Piet Demeester

Receiver Oriented Trajectory Based Forwarding

Abstract

Trajectory Based Forwarding (TBF) is a new approach to routing in ad hoc wireless networks. It exploits node position information and, similarly to source routing, requires the source node to encode a trajectory into the packet header. The routing process does not require to specify forwarding nodes. As a matter of fact, forwarding nodes are dynamically selected while packets cross the network according to their position with respect to the trajectory. Therefore, this new approach is particularly suitable for application scenarios where network topology is fast varying, due to node mobility (e.g. inter-vehicular networks) or to energy management schemes (e.g. sensor networks), whereas the stability of the trajectories is guaranteed by the physical characteristics of the service area (roads, building aisles, etc.).

This paper describes a new TBF scheme that shifts forwarding decision from transmitter to receiver exploiting broadcast transmissions. We thoroughly analyze the behavior and the properties of the proposed scheme considering the impact of the medium access control mechanism and the effect of limited transmission ranges. We consider piecewise lines connecting source node to destination area and we extend the approach to the multicast case by defining trajectory-trees. Moreover, we propose a forwarding mechanism able to walk around obstacles along the trajectory.

Antonio Capone, Ilario Filippini, Luigi Fratta, Luca Pizziniaco

Power-Controlled Directional Medium Access Control for Wireless Mesh Networks

Abstract

Wireless Mesh Networks have emerged recently as a technology for next-generation wireless networking. To increase the performance of wireless nodes in such networks many approaches have been proposed, including directional and adaptive antennas. However, while adaptive antennas can improve the utilization of the wireless medium by reducing radio interference and the impact of the exposed nodes problem, they can also exacerbate the hidden nodes problem. Thus, MAC protocols for adaptive antennas need to be carefully designed to cope with this issue.

In this regard we propose a novel MAC protocol that exploits the potentials offered by adaptive antennas in Wireless Mesh Networks to improve system performance. As key innovative feature of the proposed MAC protocol with respect to existing solutions, the information about wireless medium reservation is spread to the maximum possible extent without interfering with the connections already established in the network. This is achieved by transmitting RTS/CTS frames in all antenna sectors at the maximum allowed power that does not cause interference with ongoing transmissions. The DATA/ACK exchange then takes place directionally and at the minimum necessary power.

We measure the performance of the proposed MAC protocol by simulation in several realistic network scenarios, and we compare it with the most notable solutions proposed in the literature. The results show that our proposed scheme allows to increase considerably both the total traffic accepted by the network and fairness between competing connections.

Antonio Capone, Fabio Martignon

Achieving Flow Isolation in 802.11 Networks with the DTT Scheduler

Abstract

Though the IEEE 802.11 standard has reached wide acceptance, its main access function, the Distributed Coordination Function (DCF), still suffers from some relevant problems coming from the specific features of the wireless channel. By means of simulation, we analyse the performance anomaly and the “inter-flow blocking” problems, highlighting the mechanisms that generate them. Starting from these insights, we propose a simple centralized channel aware scheduling algorithm, named Deficit Transmission Time (DTT). The basic principle under the DTT is measuring the channel quality in terms of frame transmission times. This measurement is then used to take scheduling decisions that guarantee each downlink flow an equal time share of the channel. The proposed scheduler has been developed and deployed in a Linux-based prototype AP to experimentally evaluate its performance. The results clearly show the improvements introduced by the DTT in terms of flow isolation and reduction of the effects of the performance anomaly.

Rosario G. Garroppo, Stefano Giordano, Stefano Lucetti, Luca Tavanti

Subnet Formation and Address Allocation Approach for a Routing with Subnets Scheme in MANETs

Abstract

Due to MANET topological routing algorithms are not scalable respect to the number of nodes in the network, we evaluate the potential use of a subnet structure in MANETs. We show scenarios in which a MANET with subnet structure is applicable, present the main technical challenges for the application of this structure and show that a reduction of routing overhead from a factor of N² to N²/k (being N the number of nodes and k the number of subnets) is reachable. In this paper we propose a Subnet Formation and Address Allocation mechanism and evaluate analytically the influence of this proposal on the overhead generated. This solution is only one of the many challenges to fix for putting in use a MANET with subnets structure.

Johann López, José M. Barceló, Jorge García-Vidal

The State of the Art in Cross-Layer Design for Wireless Sensor Networks

Abstract

The literature on cross-layer protocols, protocol improvements, and design methodologies for wireless sensor networks (WSNs) is reviewed and a taxonomy is proposed. The communication protocols devised for WSNs that focus on cross-layer design techniques are reviewed and classified, based on the network layers they aim at replacing in the classical open system interconnection (OSI) network stack. Furthermore, systematic methodologies for the design of cross-layer solution for sensor networks as resource allocation problems in the framework of non-linear optimization are discussed. Open research issues in the development of cross-layer design methodologies for sensor networks are discussed and possible research directions are indicated. Finally, possible shortcomings of cross-layer design techniques such as lack of modularity, decreased robustness, and instability are discussed, and precautionary guidelines are presented.

Tommaso Melodia, Mehmet C. Vuran, Dario Pompili

Cellular Systems: Models and Algorithms

Modelling Restricted Accessibility for Wireless Multi-service Systems

Abstract

Some fundamental aspects of restricted availability and accessibility for multi-rate traffic are clarified. In classical teletraffic models all connections have the same bandwidth demand. In service-integrated systems each service has individual bandwidth requirement. For example in CDMA systems we may experience blocking (outage) even if the nominal capacity of a cell has not been fully used, because the actual capacity depends on interference from neighboring cells. Therefore, calls will experience individual accessibility. This paper presents a new theory and model for this problem. The model preserves the reversibility and insensitivity and generalizes the basic knowledge of classical teletraffic models. The theory is illustrated by a WCDMA traffic model.

Villy B. Iversen

A Low Computation Cost Algorithm to Solve Cellular Systems with Retrials Accurately

Abstract

This paper proposes an approximate methodology for solving Markov models that compete for limited resources and retry when access fails, like those arising in mobile cellular networks. We limit the number of levels that define the system by aggregating all levels beyond a given one in order to manage curse of dimensionality issue. The developed methodology allows to balance accuracy and computational cost. We determine the relative error of different typical performance parameters when using the approximate model as well as the computational savings. Results show that high accuracy and cost savings can be obtained by deploying the proposed methodology.

Ma. José Doménech-Benlloch, José Manuel Giménez-Guzmán, Jorge Martínez-Bauset, Vicente Casares-Giner

An Afterstates Reinforcement Learning Approach to Optimize Admission Control in Mobile Cellular Networks

Abstract

We deploy a novel Reinforcement Learning optimization technique based on afterstates learning to determine the gain that can be achieved by incorporating movement prediction information in the session admission control process in mobile cellular networks. The novel technique is able to find better solutions and with less dispersion. The gain is obtained by evaluating the performance of optimal policies achieved with and without the predictive information, while taking into account possible prediction errors. The prediction agent is able to determine the handover instants both stochastically and deterministically. Numerical results show significant performance gains when the predictive information is used in the admission process, and that higher gains are obtained when deterministic handover instants can be determined.

José Manuel Giménez-Guzmán, Jorge Martínez-Bauset, Vicent Pla

Hierarchical Admission Control in Mobile Cellular Networks Using Adaptive Bandwidth Reservation

Abstract

We propose a novel adaptive reservation scheme designed to operate in association with the well-known Multiple Guard Channel (MGC) admission control policy. The scheme adjusts the MGC configuration parameters by continuously tracking the Quality of Service (QoS) perceived by users, adapting to any mix of aggregated traffic and enforcing a differentiated treatment among services during underload and overload episodes. We compare our adaptive scheme with two previously relevant proposals. The comparative performance evaluation carried out verifies that our scheme outperforms the two previous proposals in terms of both carried traffic and convergence speed to new operating conditions. Other key features of our scheme are its simplicity, its oscillation-free behavior, and its integrated strategy to deal with multiservice scenarios.

David Garcia-Roger, Ma. José Doménech-Benlloch, Jorge Martínez-Bauset, Vicent Pla

Interference Estimation for the HSDPA Service in Heterogeneous UMTS Networks

Abstract

For the planning and deployment of the 3.5G enhancement of UMTS, the High Speed Downlink Packet Access, mobile telecommunication providers need to estimate the signal-to-interference-ratio of the HSDPA users. Although the received signal power is easy to calculate due the channel adaptive principle of HSDPA, the received interference includes the signal powers of the power controlled dedicated channel users and is therefore more challenging. Our contribution is a semi-analytical method to calculate the spatial distribution of the received interference. The method considers the interference generated in the own cell and in the surrounding cells including the load dependent interference coming from the dedicated channel users.

Andreas Mäder, Dirk Staehle

QoS Support in Next Generation Networks

Service Level Agreement Enforcement for Differentiated Services

Abstract

This paper describes a hierarchical architecture of active policies that performs the management of a differentiated services (DiffServ) network. These policies monitor quality of service (QoS) parameters and dynamically optimize some aspects of the existing equipment and services to provide the best possible QoS to users. This helps the enforcement of a Service Level Agreement (SLA) between a provider and users. The results show that the use of active policies improves the service offered to users, by constantly adapting to the network state, and helping to fulfill SLAs with minimum costs to the service provider.

Paulo Rogério Pereira

MIPv6 Binding Authentication for B3G Networks

Abstract

In last years, the introduction of new wireless communication systems has stimulated the technical and scientific community to investigate future evolution scenarios for 3G networks, generically referred to as Beyond-3G or 4G. In order to guarantee high end-to-end quality of service and security, Beyond-3G networks will cope with some issues such as session security in wireless environments and seamless mobility among different coverage domains and, possibly, access technologies. In this paper we analyze the security threats emerging from some mechanisms for mobility management, and we propose a solution to improve the security level under the assumption that both communicating terminals are attached to a 3GPP IP Multimedia Subsystem that supports both the Session Initiation Protocol and the Mobile IP version 6 protocol.

Domenico Celentano, Antonio Fresa, Maurizio Longo, Fabio Postiglione, Anton Luca Robustelli

Dynamic Resource Allocation in Quality of Service Networks

Abstract

Efficient dynamic resource provisioning algorithms are necessary to the development and automation of Quality of Service (QoS) networks. The main goal of these algorithms is to offer services that satisfy the QoS requirements of individual users while guaranteeing at the same time an efficient utilization of network resources. In this paper we introduce a new service model that provides quantitative per-flow bandwidth guarantees, where users subscribe for a guaranteed rate; moreover, the network periodically individuates unused bandwidth and proposes short-term contracts where extra-bandwidth is allocated and guaranteed exclusively to users who can exploit it to transmit at a rate higher than their subscribed rate. To implement this service model we propose a dynamic provisioning architecture for intra-domain Quality of Service networks. We develop an efficient bandwidth allocation algorithm that takes explicitly into account traffic statistics to increase the users’ benefit and the network revenue simultaneously. We demonstrate through simulation in realistic network scenarios that the proposed dynamic provisioning model is superior to static provisioning in providing resource allocation both in terms of total accepted load and network revenue.

Antonio Capone, Jocelyne Elias, Fabio Martignon, Guy Pujolle

Peer to Peer Architectures and Services

A P2P-Based Framework for Distributed Network Management

Abstract

In this paper we present a novel framework supporting distributed network management using a self-organizing peer-to-peer overlay network. The overlay consists of several Distributed Network Agents which can perform distributed tests and distributed monitoring for fault and performance management. In that way, the concept is able to overcome disadvantages that come along with a central management unit, like lack of scalability and reliability.

So far, little attention has been payed to the quality of service experienced by the end user. Our self-organizing management overlay provides a reliable and scalable basis for distributed tests that incorporate the end user. The use of a distributed, self-organizing software will also reduce capital and operational expenditures of the operator since fewer entities have to be installed and operated.

Andreas Binzenhöfer, Kurt Tutschku, Björn auf dem Graben, Markus Fiedler, Patrik Arlos

Time-Discrete Analysis of the Crawling Strategy in an Optimized Mobile P2P Architecture

Abstract

Mobile networks differ from their wireline counterparts mainly by the high costs for air transmissions and by the mobility of the users. A new entity, denoted as the crawling peer, is suggested in order to optimize the resource mediation mechanism for a mobile P2P file sharing application. In [1], we have investigated the performance of a crawling peer by means of simulations. Now, we show a time-discrete analysis of the crawling peer’s performance in order to investigate different scenarios and to enable parameter-sensitivity studies for further improvements of the crawling peer’s strategy.

Tobias Hoßfeld, Andreas Mäder, Kurt Tutschku, Frank-Uwe Andersen

P2P-Based Mobility Management for Heterogeneous Wireless Networks and Mesh Networks

Abstract

The recent emergence of a whole plethora of new wireless technologies, such as IEEE802.15, IEEE802.11, and UMTS, etc, has exposed the limitations of mobility solutions in the next generation Internet. Current mobility management systems are operator specific, centralized, and focused on single link technology. A rethink of how to exploit context awareness, lead by the emergence of sensor networks and pervasive computing, is explored. This paper suggests a roaming technique taking pervasiveness and self-awareness into consideration, by first, moving the intelligence to the mobile terminals. The mobile devices should look themselves for the most suitable wireless network. We also propose to organize the wireless mesh networks in a context-aware peer-to-peer network.

Amine M. Houyou, Hermann De Meer, Moritz Esterhazy

The Throughput Utility Function: Assessing Network Impact on Mobile Services

Abstract

Based on the need for distributed end-to-end quality management for next-generation mobile Internet services, this paper presents a ready-to-deploy quality assessment concept for the impact of the network on the performance of mobile services. We consider the Throughput Utility Function (TUF) as a special case of the Network Utility Function (NUF). These functions combine the observed network utility at the inlet and the outlet of a mobile network. NUF and TUF capture the damping effect of the network onto user-perceived quality from an end-to-end perspective. As opposed to sometimes hard-to-evaluate QoS parameters such as delay and loss, the NUF is highly intuitive due to its mapping to a simple value between 0 and 100 %, which reflects user perception. We demonstrate the capabilities of the proposed TUF by measurements of application-perceived throughput conducted in a mobile, i.e. GPRS and UMTS network.

Markus Fiedler, Kurt Tutschku, Stefan Chevul, Lennart Isaksson, Andreas Binzenhöfer

Measurement of Application-Perceived Throughput of an E2E VPN Connection Using a GPRS Network

Abstract

Based on the need for secure and reliable mobile communication, this paper investigates the application-perceived throughput of an end-to-end (E2E) VPN connection using IPSec over GPRS. GPRS is of particular interest regarding performance issues due to its wide deployment but limited capacity. To this end, different encryption and authentication algorithms are considered. The throughput is measured on small time scales and interpreted with aid of summary statistics, histograms and autocorrelation coefficients. The results reveal a clear influence of the network and the chosen security solution, seen from variations of application-perceived throughput on the one-second time scale, which has to be considered when assessing the appropriateness of network for a specific task. The different statistical metrics considered will later be used in our research to maintain the security and Quality of service (QoS) of the service decided by the user.

Stefan Chevul, Lennart Isaksson, Markus Fiedler, Peter Lindberg

Scenarios for Mobile Community Support

Abstract

Ubiquitous community support systems have the potential to ease daily life through delivering valuable interactive information and member contacts right in the place where they are needed. Since in real life humans move permanently between communities, we aim in our position paper at building an inter-operable community infrastructure based on the mobile JXME open source peer-to-peer system which focuses on seamless switching between different community types. On top of the JXME based file sharing service we currently implement a situation aware search layer to compensate the limited interaction possibilities of small screens. We show that raw context data can be gathered directly from the smart phone. To avoid cumbersome retrieval times we apply sociological and personal behaviour models to predict information requests.

Bernhard Klein, Helmut Hlavacs

Backmatter

Titel: Wireless Systems and Network Architectures in Next Generation Internet
herausgegeben von: Matteo Cesana
Luigi Fratta
Verlag: Springer Berlin Heidelberg
Electronic ISBN: 978-3-540-34026-3
Print ISBN: 978-3-540-34025-6
DOI: https://doi.org/10.1007/11750673