Showing papers on "Heterogeneous network published in 2009"

Network virtualization: state of the art and research challenges

Abstract: Recently network virtualization has been pushed forward by its proponents as a long-term solution to the gradual ossification problem faced by the existing Internet and proposed to be an integral part of the next-generation networking paradigm. By allowing multiple heterogeneous network architectures to cohabit on a shared physical substrate, network virtualization provides flexibility, promotes diversity, and promises security and increased manageability. However, many technical issues stand in the way of its successful realization. This article investigates the past and the state of the art in network virtualization along with the future challenges that must be addressed to realize a viable network virtualization environment.

Ranking-based clustering of heterogeneous information networks with star network schema

Abstract: A heterogeneous information network is an information networkcomposed of multiple types of objects. Clustering on such a network may lead to better understanding of both hidden structures of the network and the individual role played by every object in each cluster. However, although clustering on homogeneous networks has been studied over decades, clustering on heterogeneous networks has not been addressed until recently.A recent study proposed a new algorithm, RankClus, for clustering on bi-typed heterogeneous networks. However, a real-world network may consist of more than two types, and the interactions among multi-typed objects play a key role at disclosing the rich semantics that a network carries. In this paper, we study clustering of multi-typed heterogeneous networks with a star network schema and propose a novel algorithm, NetClus, that utilizes links across multityped objects to generate high-quality net-clusters. An iterative enhancement method is developed that leads to effective ranking-based clustering in such heterogeneous networks. Our experiments on DBLP data show that NetClus generates more accurate clustering results than the baseline topic model algorithm PLSA and the recently proposed algorithm, RankClus. Further, NetClus generates informative clusters, presenting good ranking and cluster membership information for each attribute object in each net-cluster.

Dynamics of Network Selection in Heterogeneous Wireless Networks: An Evolutionary Game Approach

Abstract: Next-generation wireless networks will integrate multiple wireless access technologies to provide seamless mobility to mobile users with high-speed wireless connectivity. This will give rise to a heterogeneous wireless access environment where network selection becomes crucial for load balancing to avoid network congestion and performance degradation. We study the dynamics of network selection in a heterogeneous wireless network using the theory of evolutionary games. The competition among groups of users in different service areas to share the limited amount of bandwidth in the available wireless access networks is formulated as a dynamic evolutionary game, and the evolutionary equilibrium is considered to be the solution to this game. We present two algorithms, namely, population evolution and reinforcement-learning algorithms for network selection. Although the network-selection algorithm based on population evolution can reach the evolutionary equilibrium faster, it requires a centralized controller to gather, process, and broadcast information about the users in the corresponding service area. In contrast, with reinforcement learning, a user can gradually learn (by interacting with the service provider) and adapt the decision on network selection to reach evolutionary equilibrium without any interaction with other users. Performance of the dynamic evolutionary game-based network-selection algorithms is empirically investigated. The accuracy of the numerical results obtained from the game model is evaluated by using simulations.

Hyrax: Cloud Computing on Mobile Devices using MapReduce

Abstract: : Today's smartphones operate independently of each other, using only local computing, sensing, networking, and storage capabilities and functions provided by remote Internet services. It is generally difficult or expensive for one smartphone to share data and computing resources with another. Data is shared through centralized services, requiring expensive uploads and downloads that strain wireless data networks. Collaborative computing is only achieved using ad hoc approaches. Coordinating smartphone data and computing would allow mobile applications to utilize the capabilities of an entire smartphone cloud while avoiding global network bottlenecks. In many cases, processing mobile data in-place and transferring it directly between smartphones would be more efficient and less susceptible to network limitations than off loading data and processing to remote servers. We have developed Hyrax, a platform derived from Hadoop that supports cloud computing on Android smartphones. Hyrax allows client applications to conveniently utilize data and execute computing jobs on networks of smartphones and heterogeneous networks of phones and servers. By scaling with the number of devices and tolerating node departure, Hyrax allows applications to use distributed resources abstractly, oblivious to the physical nature of the cloud. The design and implementation of Hyrax is described, including experiences in porting Hadoop to the Android platform and the design of mobile specific customizations. The scalability of Hyrax is evaluated experimentally and compared to that of Hadoop. Although the performance of Hyrax is poor for CPU-bound tasks, it is shown to tolerate node-departure and offer reasonable performance in data sharing. A distributed multimedia search and sharing application is implemented to qualitatively evaluate Hyrax from an application development perspective.

Methods of and apparatus for programming and managing diverse network components, including electronic-ink based display devices, in a mesh-type wireless communication network

Abstract: A wireless communication network for programming and monitoring a plurality of network-managed devices, including electronic-ink based display devices, comprising a network management computer system, a network gateway device, one or more wireless network routers, a plurality of network-managed devices, and a network coordinator. The wireless communication network of the present invention bridges the gap between wireless display networks, wireless sensor networks, and the worlds of passive, active and partially-active RFID and real-time locating systems. The wireless communication network of the present invention allows conventional communication network protocols to operate in more flexible ways in dynamic, diverse, and heterogeneous application environments, in fields including retail, healthcare, transport, logistics, manufacturing, education, etc. At the same time, the wireless communication network of the present invention is preferably based on the IEEE 802.15.4 network layer standard, which offers low-cost wireless network communication between a large number of wireless network end-devices.

UWB Systems for Wireless Sensor Networks

Abstract: Wireless sensor networks are emerging as an important area for communications. They enable a wealth of new applications including surveillance, building control, factory automation, and in-vehicle sensing. The sensor nodes have to operate under severe constraints on energy consumption and form factor, and provide the ability for precise self-location of the nodes. These requirements can be fulfilled very well by various forms of ultra-wide-band (UWB) transmission technology. We discuss various techniques and tradeoffs in UWB systems and indicate that time-hopping and frequency-hopping impulse radio physical layers combined with simple multiple-access techniques like ALOHA are suitable designs. We also describe the IEEE 802.15.4a standard, an important system that adopts UWB impulse radio to ensure robust data communications and precision ranging. In order to accommodate heterogeneous networks, it uses specific modulation, coding, and ranging waveforms that can be detected well by both coherent and noncoherent receivers.

Vertical Handoff Decision Algorithms for Providing Optimized Performance in Heterogeneous Wireless Networks

Abstract: There are currently a large variety of wireless access networks, including the emerging vehicular ad hoc networks (VANETs). A large variety of applications utilizing these networks will demand features such as real-time, high-availability, and even instantaneous high-bandwidth in some cases. Therefore, it is imperative for network service providers to make the best possible use of the combined resources of available heterogeneous networks (wireless area networks (WLANs), Universal Mobile Telecommunications Systems, VANETs, Worldwide Interoperability for Microwave Access (WiMAX), etc.) for connection support. When connections need to migrate between heterogeneous networks for performance and high-availability reasons, seamless vertical handoff (VHO) is a necessary first step. In the near future, vehicular and other mobile applications will be expected to have seamless VHO between heterogeneous access networks. With regard to VHO performance, there is a critical need to develop algorithms for connection management and optimal resource allocation for seamless mobility. In this paper, we develop a VHO decision algorithm that enables a wireless access network to not only balance the overall load among all attachment points (e.g., base stations and access points) but also maximize the collective battery lifetime of mobile nodes (MNs). In addition, when ad hoc mode is applied to 3/4G wireless data networks, VANETs, and IEEE 802.11 WLANs for a more seamless integration of heterogeneous wireless networks, we devise a route-selection algorithm for forwarding data packets to the most appropriate attachment point to maximize collective battery lifetime and maintain load balancing. Results based on a detailed performance evaluation study are also presented here to demonstrate the efficacy of the proposed algorithms.

Pervasive, secure access to a hierarchical sensor-based healthcare monitoring architecture in wireless heterogeneous networks

Abstract: This study presents a healthcare monitoring architecture coupled with wearable sensor systems and an environmental sensor network for monitoring elderly or chronic patients in their residence. The wearable sensor system, built into a fabric belt, consists of various medical sensors that collect a timely set of physiological health indicators transmitted via low energy wireless communication to mobile computing devices. Three application scenarios are implemented using the proposed network architecture. The group-based data collection and data transmission using the ad hoc mode promote outpatient healthcare services for only one medical staff member assigned to a set of patients. Adaptive security issues for data transmission are performed based on different wireless capabilities. This study also presents a monitoring application prototype for capturing sensor data from wireless sensor nodes. The implemented schemes were verified as performing efficiently and rapidly in the proposed network architecture.

Uncoverning Groups via Heterogeneous Interaction Analysis

Abstract: With the pervasive availability of Web 2.0 and social networking sites, people can interact with each other easily through various social media. For instance, popular sites like Del.icio.us, Flickr, and YouTube allow users to comment shared content (bookmark, photos, videos), and users can tag their own favorite content. Users can also connect to each other, and subscribe to or become a fan or a follower of others. These diverse individual activities result in a multi-dimensional network among actors, forming cross-dimension group structures with group members sharing certain similarities. It is challenging to effectively integrate the network information of multiple dimensions in order to discover cross-dimension group structures. In this work, we propose a two-phase strategy to identify the hidden structures shared across dimensions in multi-dimensional networks. We extract structural features from each dimension of the network via modularity analysis, and then integrate them all to find out a robust community structure among actors. Experiments on synthetic and real-world data validate the superiority of our strategy, enabling the analysis of collective behavior underneath diverse individual activities in a large scale.

Real-Time Wireless Sensor Network for Landslide Detection

Abstract: Wireless sensor networks are one of the emerging areas which have equipped scientists with the capability of developing real-time monitoring systems. This paper discusses the development of a wireless sensor network(WSN) to detect landslides, which includes the design, development and implementation of a WSN for real time monitoring, the development of the algorithms needed that will enable efficient data collection and data aggregation, and the network requirements of the deployed landslide detection system. The actual deployment of the testbed is in the Idukki district of the Southern state of Kerala, India, a region known for its heavy rainfall, steep slopes, and frequent landslides.

Recent advances in amplify-and-forward two-hop relaying

Abstract: In this article we review an important class of wireless cooperation protocols known as amplify-and-forward relaying. One or more low-complexity relay nodes assist the communication between sources and destinations without having to decode the signal. This makes AF relaying transparent to modulation and coding of the source/destination communication protocol. It is therefore a highly flexible technology that also qualifies for application in heterogeneous networks comprising many nodes of different complexity or even standards. Recently, two-way relaying was introduced, which is readily combined with AF relaying. It is a spectrally efficient protocol that allows for bidirectional communication between sources and destinations. In order to investigate the potential of wireless AF relaying, we introduce three distributed network scenarios that differ in the amount of cooperation between nodes. New challenges arise in those networks, and we discuss approaches to overcome them. For the most general case of a completely distributed system, we present coherent relaying solutions that offer a distributed spatial multiplexing gain even for single-antenna nodes. Based on real-world experiments, we validate the feasibility of all schemes in our laboratory.

Resource partitioning in heterogeneous access point networks

Abstract: Providing for dynamic resource provisioning in wireless communication is described herein. By way of example, various wireless performance metrics are collected by respective network access points as an aggregate measure of wireless network performance. Aggregated data can be utilized to generate a performance model for the network and for individual access points. Changes to the data are updated to the model to provide a steady-state characterization of network performance. Wireless resources are generated for respective access points in a manner that optimizes wireless performance. Additionally, resource assignments can be updated at various intervals to re-optimize for existing wireless conditions, whether event driven or based on performance metrics. Accordingly, a robust and dynamic optimization is provided for wireless network resource provisioning that can accommodate heterogeneous access point networks in a changing topology.

A Game Theoretical Framework on Intrusion Detection in Heterogeneous Networks

Abstract: Due to the dynamic, distributed, and heterogeneous nature of today's networks, intrusion detection systems (IDSs) have become a necessary addition to the security infrastructure and are widely deployed as a complementary line of defense to classical security approaches. In this paper, we address the intrusion detection problem in heterogeneous networks consisting of nodes with different noncorrelated security assets. In our study, two crucial questions are: What are the expected behaviors of rational attackers? What is the optimal strategy of the defenders (IDSs)? We answer the questions by formulating the network intrusion detection as a noncooperative game and performing an in-depth analysis on the Nash equilibrium and the engineering implications behind. Based on our game theoretical analysis, we derive the expected behaviors of rational attackers, the minimum monitor resource requirement, and the optimal strategy of the defenders. We then provide guidelines for IDS design and deployment. We also show how our game theoretical framework can be applied to configure the intrusion detection strategies in realistic scenarios via a case study. Finally, we evaluate the proposed game theoretical framework via simulations. The simulation results show both the correctness of the analytical results and the effectiveness of the proposed guidelines.

Hotspot network access system and method

Abstract: A system and method are disclosed for providing wireless network access to a user of a remote device at a hotspot. In general, wireless communication is established by the system with the remote device to enable wireless transmission therefrom of social networking credentials associated with a social network profile maintained by a third party social network service provider. Using these credentials, the user is authenticated with the third party social network service provider, and, upon authentication, is provided wireless access to the network.

5G Mobile Phone Concept

Abstract: Today 3G mobile systems are on the ground providing IP connectivity for real-time and non-real-time services. On the other side, there are many wireless technologies that have proven to be important, with the most important ones being 802.11 Wireless Local Area Networks (WLAN) and 802.16 Wireless Metropolitan Area Networks (WMAN), as well as ad-hoc Wireless Personal Area Network (WPAN) and wireless networks for digital TV and radio broadcast. Then, the concepts of 4G is already much discussed and it is almost certain that 4G will include several standards under a common umbrella, similarly to 3G, but with IEEE 802.xx wireless mobile networks included from the beginning. The main contribution of this paper is definition of 5G (Fifth Generation) mobile network concept, which is seen as user-centric concept instead of operator-centric as in 3G or service-centric concept as seen for 4G. In the proposed concept the mobile user is on the top of all. The 5G terminals will have software defined radios and modulation scheme as well as new error-control schemes can be downloaded from the Internet on the run. The development is seen towards the user terminals as a focus of the 5G mobile networks. The terminals will have access to different wireless technologies at the same time and the terminal should be able to combine different flows from different technologies. Each network will be responsible for handling user-mobility, while the terminal will make the final choice among different wireless/mobile access network providers for a given service. The paper also proposes intelligent Internet phone concept where the mobile phone can choose the best connections by selected constraints and dynamically change them during a single end-to-end connection. The proposal in this paper is fundamental shift in the mobile networking philosophy compared to existing 3G and near-soon 4G mobile technologies, and this concept is called here - the 5G.

Architecture and enablers for optimized radio resource usage in heterogeneous wireless access networks: The IEEE 1900.4 Working Group

Abstract: Over the past decade or so, the wireless industry has undergone many significant changes. Radio systems have moved toward forming heterogeneous wireless networks: collaborations of multiple radio access networks, which in some cases operate different radio access technologies, such as second- and third-generation cellular RATs, IEEE 802.x wireless standards, and so on. On the other hand, multimode reconfigurable user devices with the ability to choose among various supported RATs have become a reality, and devices and networks with dynamic spectrum access capabilities, allowing real-time sharing of spectrum resource usage among different systems, are expected to be a part of the future radio eco-space. As a result of these changes, there is a need to develop a standard that addresses the requirements and leverages the opportunities posed by such a versatile radio environment. To this end, IEEE 1900.4 aims to standardize the overall system architecture and information exchange between the network and mobile devices, which will allow these elements to optimally choose from available radio resources. In other words, the standard facilitates the distributed dynamic optimization of the usage of spectrum offered by the heterogeneous wireless network, relying on a collaborative information exchange between networks and mobile devices, thereby acting as a common means to improve overall composite capacity and quality of service for the served networks. This article provides a snapshot of IEEE P1900.4 in its current form, covering the scope and purpose of the standard, reference use cases for which the standard is applicable, its system and functional architectures, and finally, the information model for its main interfaces.

System and methods to monitor and analyze events on wireless devices to predict wireless network resource usage

Abstract: System and methods to monitor and analyze events on a wireless device to predict wireless network usage are described. An example method to predict the use of wireless network resources from usage data of wireless devices when executed receives data related to a user interaction with a wireless device in an offline mode, analyzes the received data to predict wireless network resource usage of the wireless device, and outputs information associated with the analyzed data to enable allocation of wireless network resources.

Operator configurable preferred network and radio access technology selection for roaming Multi-RAT capable devices

Abstract: A multi-RAT capable wireless device and a method for execution in a multi-RAT capable wireless device are provided. The wireless device maintains a registration history of all wireless network,RAT combinations through which the wireless device has previously attempted to register with data communication service registration point. Upon an event triggering network registration, the wireless device identifies a set of available wireless network,RAT combinations, selects an available wireless network,RAT combination from the set of available wireless network,RAT combinations having regard to the registration history and a preferred network,RAT combination list stored at the wireless device and attempts to register with the data communication service registration point through the available wireless network,RAT combination that has been selected. If the attempt is successful, the wireless device receives an update to the preferred network,RAT combination list and updates the preferred network,RAT combination list stored at the wireless device.

A stochastic geometry approach to coexistence in heterogeneous wireless networks

Abstract: With the increasing proliferation of different communication devices sharing the same spectrum, it is critical to understand the impact of interference in heterogeneous wireless networks. In this paper, we put forth a mathematical model for coexistence in networks composed of both narrowband (NB) and ultrawideband (UWB) wireless nodes, based on fundamental tools from stochastic geometry. Our model considers that the interferers are spatially scattered according to a Poisson field, and are operating asynchronously in a wireless environment. We first determine the statistical distribution of the aggregate interference for both cases of NB and UWB emitters. We then provide error probability expressions for two dual configurations: 1) a NB victim link subject to the aggregate UWB interference, and 2) a UWB victim link subject to the aggregate NB interference. The results show that while the impact of a single interferer on a link is often negligible due to restrictions on the transmitted power, the aggregate effect of multiple interferers may cause significant degradation. Therefore, aggregate interference must be considered to ensure coexistence in heterogeneous networks. The proposed analytical framework shows good agreement with physical-level simulations of the system.

Virtual scheduling in heterogeneous networks

Abstract: Providing for virtual management of wireless resources in a mobile communication environment is described herein. By way of example, access terminals in the communication environment can maintain connections with nearby network transmitters and report factors pertinent to wireless scheduling to a central entity, such as a macro base station. The macro base station can employ those factors in improving wireless communications for other serving cells within or near to a macro coverage area served by the macro base station. By maintaining information pertinent to prevailing wireless conditions, quality of service requirements, pilot signal reports, mobility management considerations, and so on, of transmissions within the cell, significant interference reduction can be implemented for the macro coverage area, or nearby coverage areas.

Location of wireless mobile terminals

Abstract: Methods, systems, processor-readable media, and devices for collecting information pertaining to the configuration of one or more wireless networks and using this information in turn to estimate the location of mobile wireless devices associated with those networks are disclosed. Also disclosed are methods, systems, processor-readable media, and devices for discovering and/or maintaining wireless transmitter characteristics corresponding to one or more wireless networks. Also disclosed are methods, systems, processor-readable media, and devices for aggregating wireless network transmitter characteristics from a plurality of wireless network transmitters. The present disclosure can be used across multiple networks, without requiring information from the operators of those networks, in which the information concerning those networks is collected and maintained in a current state efficiently and with rapid response to changes in the network configuration.

Distributed or Centralized Mobility

Abstract: Expecting a significant increase in number of mobile terminals to be managed together with a mobile data traffic boom in future heterogeneous networks, current centralized mobility management schemes may encounter scalability issues due to the creation of network bottlenecks and single point of failures. Recently, alternative approaches have been proposed to better distribute mobility management entities not only in the control plane but also in the data one like the "Dynamic Mobility Anchoring" scheme we designed. In this article we compare centralized and distributed approaches and describe our simulation environment using TCP in both schemes. The obtained results validate the adequacy and design of "Dynamic Mobility Anchoring". They confirm that we may expect interesting benefits in terms of handover latency and global scalability when moving towards such a distributed mobility management in future networks.

An Intelligent Alarm Management System for Large-Scale Telecommunication Companies

Abstract: This paper introduces an intelligent system that performs alarm correlation and root cause analysis. The system is designed to operate in large-scale heterogeneous networks from telecommunications operators. The proposed architecture includes a rules management module that is based in data mining (to generate the rules) and reinforcement learning (to improve rule selection) algorithms. In this work, we focus on the design and development of the rule generation part and test it using a large real-world dataset containing alarms from a Portuguese telecommunications company. The correlation engine achieved promising results, measured by a compression rate of 70% and assessed in real-time by experienced network administrator staff.

Complex networks-based energy-efficient evolution model for wireless sensor networks

Abstract: Based on complex networks theory, we present two self-organized energy-efficient models for wireless sensor networks in this paper. The first model constructs the wireless sensor networks according to the connectivity and remaining energy of each sensor node, thus it can produce scale-free networks which have a performance of random error tolerance. In the second model, we not only consider the remaining energy, but also introduce the constraint of links to each node. This model can make the energy consumption of the whole network more balanced. Finally, we present the numerical experiments of the two models.

Monitoring connectivity in wireless sensor networks

Abstract: It is important to have continuous connectivity in a wireless sensor network after it is deployed in a hostile environment. However, such networks are constrained by the low user-to-node ratio, limited energy and bandwidth resources, entities that are usually mobile, networks without fixed infrastructure and frequent failure due to problems of energy, vulnerability to attack, etc. To address these difficulties, there is a need for wireless sensor networks to be self-organizing and self-configuring so as to improve performance, increase energy efficiency, save resources and reduce data transmission. In this paper, we present a method for monitoring, maintaining and repairing the communication network of a dynamic mobile wireless sensor network, so that network connectivity is continuously available and provides fault tolerance. Specifically, we propose an algorithm for the detection and surveillance of articulation points in graph connectivity, including an algorithm for network auto-organization in the event that this occurs.

Jamming transition in air transportation networks

Abstract: In this work we present a model of an air transportation traffic system from the complex network modelling viewpoint. In the network, every node corresponds to a given airport, and two nodes are connected by means of flight routes. Each node is weighted according to its load capacity, and links are weighted according to the Euclidean distance that separates each pair of nodes. Local rules describing the behaviour of individual nodes in terms of the surrounding flow have been also modelled, and a random network topology has been chosen in a baseline approach. Numerical simulations describing the diffusion of a given number of agents (aircraft) in this network show the onset of a jamming transition that distinguishes an efficient regime with null amount of airport queues and high diffusivity (free phase) and a regime where bottlenecks suddenly take place, leading to a poor aircraft diffusion (congested phase). Fluctuations are maximal around the congestion threshold, suggesting that the transition is critical. We then proceed by exploring the robustness of our results in neutral random topologies by embedding the model in heterogeneous networks. Specifically, we make use of the European air transportation network formed by 858 airports and 11 170 flight routes connecting them, which we show to be scale-free. The jamming transition is also observed in this case. These results and methodologies may introduce relevant decision-making procedures in order to optimize the air transportation traffic.

Personal wireless network user behavior based topology

Abstract: Point-to-point links making up a wireless network in which the point-to-point links connect at least personal portable devices are dynamically altered (i.e., new point-to-point links are established and/or other point-to-point links are removed) in response to recurring comparisons of the extents of interaction of each of the personal portable devices with the wireless network to increase the resiliency of the wireless network to the observed behavior of the user of the personal portable devices in changing which personal portable devices are within the network at any given time.