Next Generation Teletraffic and Wired/Wireless Advanced Networking

In this paper we address estimation/control methods in complex networks where a global estimate (or decision) is obtained in a distributed fashion without fusion or centralized control centers. The suggested approach is based on local exchange of information among the nearby nodes within a connected (wireless) network that allows, under certain conditions, to reach a global decision based on locally available decisions/measurements. In particular, we consider network nodes as local dynamical systems with impulse-like coupling to establish time synchronization among the transmitted packets together with phase-coupling during packet durations to achieve distributed estimation/control. The suggested method may be used for distributed spectral sensing in cognitive radio and wireless sensor networks.

In this paper we consider a cross-layer MAC-PHY technique that combines the collision resolution tree algorithm (TA) with the possibility of successive interference cancellation (SIC). The overview of the previous work shows that no simple protocol has been proposed to use a single memory location for the captured signal. We, consequently, propose two such protocols that demonstrate the throughput - implementation complexity trade-off. Further, we address the system operation during which interference cancellation errors are possible. We propose the third protocol that is resistant to cancellation errors. A simple yet effective technique is applied to address the throughput performance of all three protocols to demonstrate their superiority over known conventional TA protocols.

Overloading is a scheme to accommodate more users than the spreading factor

N

. This is a bandwidth efficient scheme to increase the number of users in a fixed bandwidth. One of the efficient schemes to overload a CDMA system is to use two sets of orthogonal signal waveforms (O/O). The first set is assigned to the

N

users and the second set is assigned to the additional users. An iterative multistage detection (IMSD) technique is used to cancel interference between the two sets of users. The interference cancellation receiver uses hard decisions (HDIC) or soft decisions (SDIC) to estimate the interference. In this paper, the BER performance of a new overloading scheme using scrambled orthogonal Gold code (OG/OG) sets is evaluated with SDIC receiver. When complex scrambling is not used, it is shown that OG/OG scheme provides 25% (16 extra users) channel overloading for synchronous DS-CDMA system in an AWGN channel, with an SNR degradation of about 0.35 dB as compared to single user bound at a BER of 10

 − 5

. We have evaluated the overloading performance, when the two set are scrambled with set specific deterministic or random complex scrambling sequence. It is shown that the amount of overloading increases significantly from 25% to 63% (40 extra users) by using random complex scrambling for N=64. For deterministic (periodic) scrambling, the overloading percentage increases considerably to 78%. On a Rayleigh fading channel, an overloading of 100% is obtained at a BER of 10

 − 5

with near single user user performance.

Recently standardized, WiMAX promises high data rates over long ranges. It defines two modes of operation Point-to-Multi-Point PMP and MESH. In the PMP mode, subscriber stations (SSs) connect to the base station (BS) in single-hop transmissions. The mesh mode on the other hand, allows direct communications between SSs. WiMAX mesh networks constitute a real solution for extending the coverage of the BS. They can be used for providing access into under-covered zones like rural areas and hard-to-wire areas. Several aspects affect the performance of the mesh, such as routing, scheduling and SS locations which when optimized, result in improved performance in term of capacity. In order to cover a specific area, we propose a placement algorithm that adequately places the SSs using routing and scheduling algorithms that we have previously proposed for the purpose of maximizing the capacity. Knowing that placement problems are NP-Hard, we design a heuristic with two variants and we show by simulations, that our algorithms, compared to the intuitive bottom-up approach, always find the smallest number of SSs, but also guarantee a required data rate.

Performance control of applications running over wireless channels depends on ability to estimate statistical characteristics of wireless channels in real-time and represent them in terms of the model. Inherent time-varying dynamics of these characteristics pose a number of problems that have to be addressed before reliable estimates of the current channel state will be available. In this paper we consider the problem of on-line estimation of the state of the wireless channel based on bit error observations. The proposed approach is based on smoothing of the original error sequence which is shown to provide better description of the wireless channel for any given instant of time compared to conventional approaches. We also discuss applicability of the proposed approach in performance control of applications running over the air interface.

Many optimization theoretic based rate allocation strategies have been developed for allocating some optimal rates to the competing users in wireless ad hoc networks. By considering different objective functions (such as congestion level, total packet loss and so on), the researchers propose some optimization framework by which the problem can be solved. Due to the rapid increase in the development of different video applications in such environments and the existence of difficulties in satisfying the pre-specified QoS limits, increasing the received video quality can be considered as an important and challenging issue. The quality of the received video stream is inversely proportional to the amount of distortion which is being imposed on the video stream by the network packet loss and the video encoder. The main objective of the current paper is to introduce an optimization framework in which by optimal rate allocation to some competing video sources, the aggregate distortion of the all of the sources be minimized. The simulation results verify the claims.

In this paper we consider a problem of building a forwarding tree for multicast and convergecast traffic in short-range wireless sensor networks. Interference awareness and energy efficiency are the major design objectives for WSN protocols in order to maximize the network lifetime. The existing multicast algorithms aim at constructing low-energy cost trees. Adding interference-awareness, however, leads to increased throughput and further reduces the energy consumption by avoiding unnecessary retransmissions due to interference-induced packet losses. We propose a Localized Area-Spanning Tree (LAST) protocol for wireless short-range sensor networks. Unlike previous similar protocols, the LAST protocol reaches all the nodes in a given geographical area, rather than only specific individual nodes. When creating the tree, the protocol jointly optimizes the energy cost and the interference imposed by the structure.

The optimum resource allocation in relay networks is used to improve the error performance and increase the energy efficiency. In this paper, a two-dimensional resource allocation, i.e., the energy optimization and location optimization, is carried out based on the average symbol error rate (SER) for the system with and without a direct link. Differential modulation which bypasses the channel estimation at the transceiver is investigated using amplify-and-forward protocol for the system with multiple relays. We also show that the minimum error rate can be achieved via the joint energy-location optimization.

With increasing attractiveness of location-based services (LBS), the need for consistent establishment and deployment of the LBS Quality of Service (QoS) hierarchy is strongly demanded. The position estimation is in the heart of every location-based service. Thus, LBS QoS is primarily concerned with position estimation performance, including position estimation errors and response time, achieved by either single position sensor, or a combination of several position estimation sensors and methods. Common LBS QoS establishment approach consists of either “as-is” (i. e. no-guarantee) or “best-effort” (again no-guarantee, but with some concern) approach. The proposed new solution starts with generic description of LBS QoS and methods for its deployment. As the result a method emerges that utilises position estimation by adaptive selection of positioning sensors based on requested QoS.

In IP-based wireless networks, minimizing handover latency with few packet loss is one of the most important issues. To achieve this goal, host-based and network-based fast or localized mobility management solutions have been proposed. Proxy Mobile IPv6(PMIPv6) avoids tunneling overhead over the air and supports mobility for hosts without host involvement. However, the basic performance of PMIPv6 for handover latency and packet loss is not different from that of Mobile IPv6.In this paper, we propose an enhancement for PMIPv6 to reduce the

packet reception latency

and to minimize

packet loss

for both intra-local mobility anchor(LMA) and inter-LMA handover by pre-establishing bidirectional tunnel between MAGs within an administrative domain. As a result, we found that the proposed scheme, though it requires additional signaling messages to establish the bidirectional tunnels, guarantees lower packet reception latency and fewer packet loss than other recent approaches without erroneous movement prediction.

Session Initiation Protocol (SIP) is an application-layer protocol to handle sessions between two points. SIP is implemented on the top of the transport protocols, such as user datagram protocol (UDP) or transmission control protocol (TCP). SIP messages are transmitted by UDP or TCP. We focus on an interaction between the application layer (SIP) and the transport layer (UDP or TCP). The paper studies how the interaction affects performance of SIP signaling. A significant performance difference was found to exist because of the interaction. In the case of SIP over UDP, retransmissions of SIP messages decrease throughput. On the other hand, in the case of SIP over TCP, a large TCP buffer causes a large call setup delay although TCP improves throughput.

Recent measurement studies of network traffic and variable bit rate video indicate that the traffic exhibits long-range dependence (LRD). It becomes more and more important to model this kind of traffic. This paper presents a traces-generating framework based on TES (Transform-Expand-Samples) and simple synthetic Markov-Gaussian processes for modeling LRD traffic with variability over several time scales. All of the traffic studies showed that the measurement exhibits

approximate

second-order self-similarity. The network resource is limited and the

real

long-range dependent traffic has no room under the circumstances. The proposed framework can fit both the probability density function of the empirical traces and the autocorrelation function spanning over several time scales. Besides, we discuss the validity of approximate LRD modeling with the short-range-dependent approaches.

In this paper we construct a model of a multi-service system with an arbitrary number of bandwidth flow demands, taking into account retrials due to both blocking along the route and to called-party-busy. An approximate algorithm for estimation of key performance measures is proposed, and the problem of dimensioning the system is considered.

IEEE 802.11 MAC protocol ist the de facto standard for wireless local area networks (WLANs). In today’s Internet, the emerging widespread use of real-time voice, audio, and video applications makes QoS (Quality of Service) a key problem. At the MAC layer, 802.11e defines extensions to enhance the QoS performance of 802.11 WLAN. This MAC layer solution leaves such issues of QoS as QoS guarantee and admission control to the traffic control systems at the higher layers. This article tries to show that implementation of some mechanisms of traffic shaping causes some improvement of the level of QoS in WLANs. First we analyse the influence of the traffic shaping in WLANs stations by the mechanism of token bucket filter. Next the analysis of the behaviour of Access Point with AQM mechanism was carried out. The conducted research has shown that it is possible to achieve certain level of QoS thanks to the implementation of traffic shaping mechanisms. We make our experiments comparatively for the traffic sources with self-similarity and without it. Our results confirm the necessity of taking into account the self-similar character of wireless traffic.

Convergence of the cellular world to an all-IP domain has stimulated the development of Internet Multimedia Subsystem (IMS) service architecture, which is touted by service providers and vendors as the next generation solution for breaking the barriers not only between cellular and IP worlds, but also between wireline and wireless networks. Although many GSM operators and legacy network service providers are adapting rapidly to the IMS world, the pace of this adaptation process is still quite low in certain parts of the world. In this paper, we propose a novel IMS concept referred to as Service Concentration Node (SCN), which enables the operators to provide their customers with IMS services that are offered in other domains with which the operator has a signed agreement, and thereby facilitates the utilization of a vast amount of IMS services in various operator networks. The formulated technical framework as well as its accompanying business model is quite promising in enriching the IMS services experience in next generation networks.

Defined by the 3GPP, the IP Multimedia Subsystem (IMS) is becoming the de facto overlay architecture for enabling service delivery in converged environments. In such scenarios, the QoS requirements of the delivered services vary from user to user, and from service to service. To cope with this necessity, the IMS allows subscribers to personalize the QoS settings of the session that they want to establish. In order to know the impact that the requested QoS parameters have on the available network resources, it is of paramount importance to know how the signaling load in the core network is influenced by them. With this goal in mind, this paper shows how the IMS SIP signaling load is affected when users change their QoS parameters when negotiating a session. The observations were done on a testbed based on the Open IMS Core implementation of the Fraunhofer FOKUS Institute at Berlin and on the IMS Client developed at the University of Cape Town.

Presence is an important service in IMS. The user in IMS would use presence as a necessary component. But the more user uses, the harder presence information transmits. Previous researches show that the traffic increases rapidly with the presentity number grows. In this paper, we propose an approach to optimize information dissemination in IMS Presence System. Comparing with previous researches, a new architecture is set up. In this architecture, presence information transmission is modeled as a growing tree. A k sequence method is proposed to construct the tree. And some key algorithms are introduced for the tree adjustment. With a mathematical analysis, the new method is more suitable for presence information dissemination. And in the experiment, the result shows that the method can do a better job with smaller traffic and jitter.

In this paper we deal with the separation of concerns among the entities involved in multimedia sessions in Next Generation Networks (NGNs). In particular, the focus is on the explicit separation of responsibilities between Application Servers, which are in charge of the services application logic, and Media Servers, whose task is instead the low-level manipulation and delivery of media streams. The paper describes the standardization proposals coming from both the 3GPP and the IETF from a very practical point of view, and presents the reader with the currently only available implementation of the MEDIACTRL architecture. Furthermore, the paper is also devoted to describing some typical multimedia scenarios from the presented perspective, by providing an in-depth analysis of the related sequence diagrams and protocol messages.

A network defines its own Quality-Of-Service (QoS) class and has QoS support mechanisms. So, effectively to support end-to-end QoS in heterogeneous networks, a certain unified control is needed, however, it causes scalability problem as management complexity and implementation difficulty. There is a strong need to provide simple interoperability with QoS support so we present a QoS Class Mapping (QCM) framework: building blocks should be defined such as parameter mapping and class mapping. And we improve the framework, called as QCM-ASM, to support not only flawless class mapping but also fine-granular QoS in any circumstance. At last, another framework with adaptive QoS Class Selection (AQCS) mechanism, named as AQCM-ASM framework, is proposed. AQCS mechanism can prevent resource starvation of lower priority class and provide an effective resource distribution. As an experimental result, we demonstrate a performance of the proposed frameworks. The performance results show characteristics of each framework.

There are two problems, unfair and too strict, with the utility function of the proposed incentive mechanisms for restraining the free-riding in peer-to-peer (P2P) networks. This paper is devoted to establish a new fair utility function to solve those problems. We absorb both the absolute contribution value and the physical performance of peers in our utility function and the absolute contribution value is divided into supply value and profit value. Besides, we take the time the user is in the system as a factor of a peer’s utility. The mathematical modeling, Analytic Hierarchy Process (AHP), is used in this paper to construct the function. The simulations compare the fair utility function with the proposed three functions and the results verify that this function is effective to solve those two problems.

In a Hierarchical Mobile IPv6 (HMIPv6), two alternative routes are available: a Home Agent (HA) route (overlay route), and a direct communication route (flat route), which does not pass through the HA and is determined using the Return Routability procedure. The flat route is not always optimal when handover frequencies are taken into consideration. Therefore, it is necessary to select either the overlay or flat rate based on the particular communication situation. This paper proposes a communication route selection algorithm that is suitable of an HMIPv6 configuration, in which the route to be used is selected based on the packet delay measurement of each route. The algorithm’s effectiveness has been verified through a simulation of its operation, and the evaluation of the reduction in the number of delay measurement packets arriving at the HA.

In the last few years, the number and impact of security attacks over the Internet have been continuously increasing. Since it seems impossible to guarantee complete protection to a system by means of the “classical” prevention mechanisms, the use of Intrusion Detection Systems (IDSs) has emerged as a key element in network security. In this paper we address the problem considering different methods, based on the Wavelet Packet Transform, for detecting anomalies in the network traffic, taking into account both the best basis and the value of transformed coefficients.

The performance comparison among the different solutions shows that very little information about network anomalies is carried by the best basis selection, while the “distance” between the transformed coefficients leads to very interesting results, highlighting the effectiveness of the proposed approaches.

The Semantic Web is emerging as the future platform for computation. The ability to represent information, its structure and some of its semantics in a canonical form that is readable and understandable by machine forms the key infrastructure for truly ubiquitous computing. On top of this structure we are seeing the development of more sophisticated services, reasoning and applications and a re-emergence of machine intelligence in the mainstream environment.

Driven by the advances in hardware technologies, smart environments (or “pervasive computing”) already penetrate many spaces of our daily live. Smart Homes, Smart Buildings and larger ensembles like airports, hospitals or university campuses are already equipped with a multitude of mobile terminals, embedded devices as well as connected sensors and actuators. Some activities already envision the “Smart City” which uses the opportunities provided by pervasive computing technologies to the benefits of their inhabitants. In such a setting, smart environments are expected to play a crucial role for coping with the challenges of urbanization and demographic chance e.g. regarding sustainability, energy distribution, mobility, health or public safety/security.

While “smartness” is often centered on a user perspective, we give the business perspective of a large industrial supplier of infrastructures and solutions. This includes application scenarios for smart cities and an outline of the involved business- and research challenges. A particular focus will be the setup and energy efficient operation of smart infrastructures and data centers. While “autonomic computing principles” like self-configuration, self-healing, self-protection, and self-optimization are well understood for enterprise IT infrastructures, their application to highly-distributed, heterogeneous pervasive computing systems is less straightforward. A particular concern is the incorporation of energy efficiency in such settings. This involves a reduction of the rapidly raising IT energy costs and concepts for making software applications and services more aware of their energy consumption. It is therefore the basis for the identification of IT energy hotspots in software and IT system architecture and therefore for a sustainable development and operation of smart environments

Emerging pervasive computing and communications technologies evolved into ample pioneering initiatives, leading towards a world in which computing systems are distributed, mobile, intelligent, supportive, unobtrusive, invisible and cooperative. Central to the notion of a pervasive systems is context-awareness. Context-aware computing endeavours to make systems aware of specific, relevant circumstances in the computing environment, and enable them to adapt their behaviour accordingly. Context-aware systems can process (intelligently) the context information acquired by any type of a sensor (either physical, computational or virtual). This, in turn, enhances services provided to users (including service personalization), makes pervasive systems smart by reacting (and possibly pro-acting) to changing circumstances, and enables adaptability and autonomy of systems, freeing users from avoidable sometimes routine interactions.

This article discusses a topic of home automation, also called domotics, and provides an overview of state-of-the-art in communication protocols for this application area. Comparitive analysis for different networking standards and communication media is provided. Special focus is given to wireless technologies and advantages provided by ZigBee wireless networking standard for home automation solutions. ZigBee protocol implementation details are covered together with examples of possible applications in conjunction with Linux Open Source software platform.

Internet computing is entering a new era, and the traditional human targeted World Wide Web slowly but surely moves towards a Web of billions of services, where the Web resources become entities in a global service-oriented architecture. In such a world of services, it is the service that counts for a customer and not the software or hardware components that implement the application. Current service-oriented architectures are still very much restricted in their application context to corporate solutions, while a Web with billions of heterogeneous and distributed service and content providers and consumers has requirements that call for specialized solutions.

With our work on Triple Space Computing we aim at solutions to the Service Web challenges by integrating technology from tuplespace computing (blackboards), the Semantic Web and Web services. This unique synergy of technology is researched in the EC STREP TripCom and is seen as the fundamental layer for the coordination and communication of services in future Internet systems. Triple Space facilitates the reusability and integration of heterogenous knowledge, the lightweight orchestration of services, and thus enables large scale collaborative solutions in a scalable, robust and easily maintainable way.

Having the right product at the right time at the right place and in the right condition – these are the well-known requirements for logistics and transportation in general. But fulfilling these requirements is getting more and more complex in a dynamically changing logistic environment. There is a shift from traditional supply chains to open supply networks. Long-lasting business relationships are overrun by short-term business connections. The highly dynamic logistic markets and the advancing complexity of logistic networks require new methods, products and services. Aspects such as flexibility, adaptability and proactivity gain importance and can only be achieved by integration of new technologies. While problem initiated approaches usually only lead to minor improvements, technology driven approaches can evoke more radical changes. The technology driven approach that is used to define Smart Products and Smart Services is utilized and extended to define “Smart Logistics”. Within the paper a definition of Smart Logistics is given. Additionally current technical components of Smart Logistics are specified.

In a ubiquitous environment, the connections of a variety of devices, including electronic tags such as RFID (Radio Frequency Identification) tags to the network, together with an advance in Web services, are expected to give rise to a wide range of services, stimulating research into smart space services, which incorporate a sensing environment. With a view to building a convenient personal environment in such an environment, in this paper we propose a method of building a personal network (PN), which is a wide-area personal space and consists of a visited personal area network (PAN), in which the user can use devices available in a temporarily visited network for information input/output, and a home network built at home or in the office. In particular, we study a Touch&Select method, which allows the user to select an appropriate device in a visited PAN intuitively, and a monitoring protocol, which is designed to ensure connectivity of the PN. Evaluations through prototyping and simulation have verified the effectiveness of these proposals.

In this paper, inkjet-printed flexible antennas fabricated on paper substrates are introduced as a system-level solution for ultra-low-cost mass production of UHF Radio Frequency Identification (RFID) Tags and Wireless Sensor Nodes (WSN) in an approach that could be easily extended to other microwave and wireless applications. A compact inkjet-printed UHF “passive-RFID” antenna using the classic T-match approach and designed to match IC’s complex impedance, is presented as a demonstrating prototype for this technology. In addition, the authors briefly touch up the state-of-the-art area of fully-integrated wireless sensor modules on paper and show the first ever 2D sensor integration with an RFID tag module on paper, as well as the possibility of a 3D multilayer paper-based RF/microwave structures.

With advent of pervasive computing and considerable acceptance of sensor networks, smart sensing techniques and data collection have been topics of interest. This paper presents a smart sensing and data collection technique from sensor networks using context aware high powered mobile objects within the environment. The paper proposes CAM-

R

a context aware robot that can move within smart environments sensing new sensor sources and collecting sensory originated data efficiently. Based on these sensed data sources, we propose an extension to context spaces model that builds a virtual model of the intelligent environment. This intelligent environment model built using extended context spaces can be used by number of context aware applications to efficiently query and retrieve data from the sensor network using CAM-

R

based data collection approach. We also present a prototype implementation of CAM-

R

built using off-the-shelf hardware and a context based cost function used to compute data collection decisions. We validate our system by implementing the virtual modelling of the intelligent environment based on simulated input obtained from CAM-

R

and sensors. We also evaluate CAM-

R

by simulating and comparing the energy spent by the sensor nodes during data collection process using our proposed approach and traditional fixed sink based approach.

In this paper, we present the design and implementation of Ubi-Board, a context sensitive and multimodal information diffusion system. Typically, Ubi-Board consists of smart displays with the ability to sense the profile of nearby users, to adapt the information content so as it is understandable and accessible to the people, and to dynamically distribute the information to the appropriate devices, including users mobile devices when necessary.