Showing papers by "Telcordia Technologies published in 2009"

Key Technologies of WDM-PON for Future Converged Optical Broadband Access Networks [Invited]

Abstract: The wavelength-division-multiplexed passive optical network (WDM-PON) is considered to be the next evolutionary solution for a simplified and future-proofed access system that can accommodate exponential traffic growth and bandwidth-hungry new applications. WDM-PON mitigates the complicated time-sharing and power budget issues in time-division-multiplexed PON (TDM-PON) by providing virtual point-to-point optical connectivity to multiple end users through a dedicated pair of wavelengths. There are a few hurdles to overcome before WDM-PON sees widespread deployment. Several key enabling technologies for converged WDM-PON systems are demonstrated, including the techniques for longer reach, higher data rate, and higher spectral efficiency. The cost-efficient architectures are designed for single-source systems and resilient protection for traffic restoration. We also develop the integrated schemes with radio-over-fiber (RoF)-based optical-wireless access systems to serve both fixed and mobile users in the converged optical platform.

IEEE 802.21: Media independent handover: Features, applicability, and realization

Abstract: Providing users of multi-interface devices the ability to roam between different access networks is becoming a key requirement for service providers. The availability of multiple mobile broadband access technologies, together with the increasing use of real-time multimedia applications, is creating strong demand for handover solutions that can seamlessly and securely transition user sessions across different access technologies. A key challenge to meeting this growing demand is to ensure handover performance, measured in terms of latency and loss. In addition, handover solutions must allow service providers, application providers, and other entities to implement handover policies based on a variety of operational and business requirements. Therefore, standards are required that can facilitate seamless handover between such heterogeneous access networks and that can work with multiple mobility management mechanisms. The IEEE 802.21 standard addresses this problem space by providing a media-independent framework and associated services to enable seamless handover between heterogeneous access technologies. In this article, we discuss how the IEEE 802.21 standard framework and services are addressing the challenges of seamless mobility for multi-interface devices. In addition, we describe and discuss design considerations for a proof-of-concept IEEE 802.21 implementation and share practical insights into how this standard can optimize handover performance.

Halftone Visual Cryptography Via Error Diffusion

Abstract: Halftone visual cryptography (HVC) enlarges the area of visual cryptography by the addition of digital halftoning techniques. In particular, in visual secret sharing schemes, a secret image can be encoded into halftone shares taking meaningful visual information. In this paper, HVC construction methods based on error diffusion are proposed. The secret image is concurrently embedded into binary valued shares while these shares are halftoned by error diffusion-the workhorse standard of halftoning algorithms. Error diffusion has low complexity and provides halftone shares with good image quality. A reconstructed secret image, obtained by stacking qualified shares together, does not suffer from cross interference of share images. Factors affecting the share image quality and the contrast of the reconstructed image are discussed. Simulation results show several illustrative examples.

Optical networking for quantum key distribution and quantum communications

Abstract: Modern optical networking techniques have the potential to greatly extend the applicability of quantum communications by moving beyond simple point-to-point optical links and by leveraging existing fibre infrastructures. We experimentally demonstrate many of the fundamental capabilities that are required. These include optical-layer multiplexing, switching and routing of quantum signals; quantum key distribution (QKD) in a dynamically reconfigured optical network; and coexistence of quantum signals with strong conventional telecom traffic on the same fibre. We successfully operate QKD at 1310 nm over a fibre shared with four optically amplified data channels near 1550 nm. We identify the dominant impairment as spontaneous anti-Stokes Raman scattering of the strong signals, quantify its impact, and measure and model its propagation through fibre. We describe a quantum networking architecture which can provide the flexibility and scalability likely to be critical for supporting widespread deployment of quantum applications.

Dense wavelength multiplexing of 1550 nm QKD with strong classical channels in reconfigurable networking environments

Abstract: To move beyond dedicated links and networks, quantum communications signals must be integrated into networks carrying classical optical channels at power levels many orders of magnitude higher than the quantum signals themselves. We demonstrate the transmission of a 1550 nm quantum channel with up to two simultaneous 200 GHz spaced classical telecom channels, using reconfigurable optical add drop multiplexer (ROADM) technology for multiplexing and routing quantum and classical signals. The quantum channel is used to perform quantum key distribution (QKD) in the presence of noise generated as a by-product of the co-propagation of classical channels. We demonstrate that the dominant noise mechanism can arise from either four-wave mixing or spontaneous Raman scattering, depending on the optical path characteristics as well as the classical channel parameters. We quantify these impairments and discuss mitigation strategies.

MAC Protocol for Opportunistic Cognitive Radio Networks with Soft Guarantees

Abstract: Cognitive radio (CR) is the key enabling technology for an efficient dynamic spectrum access It aims at exploiting an underutilized licensed spectrum by enabling opportunistic communications for unlicensed users In this work, we first develop a distributed cognitive radio MAC (COMAC) protocol that enables unlicensed users to dynamically utilize the spectrum while limiting the interference on primary (PR) users The main novelty in COMAC lies in not assuming a predefined CR-to-PR power mask and not requiring active coordination with PR users COMAC provides a statistical performance guarantee for PR users by limiting the fraction of the time during which the PR users' reception is negatively affected by CR transmissions To provide such a guarantee, we develop probabilistic models for the PR-to-PR and the PR-to-CR interference under a Rayleigh fading channel model From these models, we derive closed-form expressions for the mean and variance of interference Empirical results show that the distribution of the interference is approximately lognormal Based on the developed interference models, we derive a closed-form expression for the maximum allowable power for a CR transmission We extend the min-hop routing to exploit the available channel information for improving the perceived throughput Our simulation results indicate that COMAC satisfies its target soft guarantees under different traffic loads and arbitrary user deployment scenarios Results also show that exploiting the available channel information for the routing decisions can improve the end-to-end throughput of the CR network (CRN)

System and method for using networked mobile devices in vehicles

Abstract: A system and method for using networked mobile devices in a vehicle in a tightly integrated manner is presented. The vehicle has an OBE, a mobile device client, and vehicle components, and the mobile device has a mobile device proxy and applications, such that the mobile device client and the mobile device proxy communicate, enabling dynamic transfer of the applications to the OBE and execution of the applications on the mobile device and the OBE using the plurality of vehicle components at runtime. In one embodiment, the mobile device client and the mobile device proxy authenticate each other. The authentication can be performed using digital certificates. The mobile device client can communicate the vehicle components on the vehicle to the mobile device proxy. The mobile device client and the mobile device proxy can communicate using Bluetooth. The vehicle components can include dashboard displays, speakers, and voice I/O systems.

Energy-Efficient Clustering/Routing for Cooperative MIMO Operation in Sensor Networks

Abstract: Employing multi-input multi-output (MIMO) links can improve energy efficiency in wireless sensor networks (WSNs). Although a sensor node is likely to be equipped with only one antenna, it is possible to group several sensors to form a virtual MIMO link. Such grouping can be formed by means of clustering. In this paper, we propose a distributed MIMO-adaptive energy-efficient clustering/routing scheme, coined cooperative MIMO (CMIMO), which aims at reducing energy consumption in multi- hop WSNs. In CMIMO, each cluster has up to two cluster heads (CHs), which are responsible for routing traffic between clusters (i.e., inter-cluster communications). CMIMO has the ability to adapt the transmission mode and transmission power on a per-packet basis. The transmission mode can be one of four transmit/receive configurations: 1 times 1 (SISO), 2 times 1 (MISO), 1 times 2 (SIMO), and 2 times 2 (MIMO). We study the performance of CMIMO via simulations. Results indicate that our proposed scheme achieves a significant reduction in energy consumption, compared to non-adaptive clustered WSNs.

Network Design and Architectures for Highly Dynamic Next-Generation IP-Over-Optical Long Distance Networks

Abstract: The DARPA CORONET project seeks to develop the target network architectures and technologies needed to build next-generation long-distance IP-over-Optical-Layer (IP/OL) networks. These next-generation networks are expected to scale 10-100 times larger than today's largest commercial IP/OL network. Furthermore, DARPA has established advanced objectives for very rapid provisioning of new IP or private line connections, very rapid restoration against up to three simultaneous network failures, and future dynamic ldquowavelengthrdquo services ranging from speeds of 40-800 Gigabits per second. Besides these ambitious goals, the CORONET project seeks to establish a commercially-viable network architecture that supports both commercial and government services. In this paper, we describe the CORONET program requirements, and present our initial architectures and analysis of the early phases of this long-term project. We propose a novel 2-Phase Fast Reroute restoration method that achieves 50-100 ms restoration in the IP-Layer in a cost-effective manner, and a commercially viable OL restoration method that can meet the rapid CORONET requirements. We also estimate the magnitude of the extra capacity needed to provide dynamic wavelength services compared to that of static services, and show that the extra capacity to restore a small percentage of high priority traffic against multiple failures requires a small amount of extra capacity compared to that of single failures.

Applications of Artificial Neural Networks in Optical Performance Monitoring

Abstract: Applications using artificial neural networks (ANNs) for optical performance monitoring (OPM) are proposed and demonstrated. Simultaneous identification of optical signal-to-noise-ratio (OSNR), chromatic dispersion (CD), and polarization-mode-dispersion (PMD) from eye-diagram parameters is shown via simulation in both 40 Gb/s on-off keying (OOK) and differential phase-shift-keying (DPSK) systems. Experimental verification is performed to simultaneously identify OSNR and CD. We then extend this technique to simultaneously identify accumulated fiber nonlinearity, OSNR, CD, and PMD from eye-diagram and eye-histogram parameters in a 3-channel 40 Gb/s DPSK wavelength-division multiplexing (WDM) system. Furthermore, we propose using this ANN approach to monitor impairment causing changes from a baseline. Simultaneous identification of accumulated fiber nonlinearity, OSNR, CD, and PMD causing changes from a baseline by use of the eye-diagram and eye-histogram parameters is obtained and high correlation coefficients are achieved with various baselines. Finally, the ANNs are also shown for simultaneous identification of in-phase/quadrature (I/Q) data misalignment and data/carver misalignment in return-to-zero differential quadrature phase shift keying (RZ-DQPSK) transmitters.

Network design and architectures for highly dynamic next-generation IP-over-optical long distance networks

Abstract: We present initial network architectures and capacity-efficient design for an IP/Optical network with highly dynamic IP and wavelength services, restoration against up to 3 failures, and aggregate traffic levels that represent a 10-fold increase over today's network traffic.

A Novel Bidirectional 60-GHz Radio-Over-Fiber Scheme With Multiband Signal Generation Using a Single Intensity Modulator

Abstract: We experimentally demonstrated a novel radio-over-fiber system to simultaneously generate dispersion-tolerant multiband downstream signals, including millimeter-wave, microwave, and baseband signals, based on multicarrier modulation in an intensity modulator and a subsequent optical filter. The uplink connection is realized by remodulation of downlink optical carrier and by baseband detection in the central office. The high-dispersion tolerance comes from the subcarrier cross-selection with only one data-bearing tone before signal beating in the receiver. The power penalty of 1.4 dB for 60-GHz carrier and negligible degradation for baseband and upstream are achieved for 2.5-Gb/s signal after 50-km single-mode fiber (SMF-28) and 4-m air link transmission. The theoretical analysis is also provided to obtain the optimal operation point.

Dynamic resource assignment and cooperative relaying in cellular networks: concept and performance assessment

Abstract: Relays are a cost-efficient way to extend or distribute high data rate coverage more evenly in next generation cellular networks. This paper introduces a radio resource management solution based on dynamic and flexible resource assignment and cooperative relaying as key technologies to enhance the downlink performance of relay-based OFDMA cellular networks. It is illustrated how the dynamic resource assignment is combined with beamforming in a macrocellular deployment and with soft-frequency reuse in a metropolitan area deployment. The cooperative relaying solution allows multiple radio access points to cooperatively serve mobile stations by combining their antennas and using themultiantenna techniques available in the system. The proposed schemes are compared to BS only deployments in test scenarios, which have been defined in the WINNER project to be representative for next generation networks. The test scenarios are well defined and motivated and can serve as reference scenarios in standardisation and research. The results show that the proposed schemes increase the average cell throughput and more importantly the number of users with low throughput is greatly reduced.

Pre-evaluation of multiple network access points

Abstract: The present application describes, inter alia, novel techniques to perform pre-evaluations of multiple Wi-Fi Access Points (AP) and Access Networks (AN). A pre-evaluation determines whether or not an AP is connected to the Internet and measures the path performance that the AN, via that particular AP, can offer between the mobile device and a pre-specified Internet host. In addition, the invention also discloses methods to determine whether the AN requires a user to actively authenticate themselves through a redirect log-on page.

Cognitive MANET design for mission-critical networks

Abstract: For mobile ad hoc networks used in network-centric operations, there is a growing need for a systematic methodology for analyzing/predicting the performance of the network over the mission duration. With the advance in cognitive networking as a possible means of exploiting unused spectrum, there is now a growing need to study how to design a cognitive network using an automated methodology. In this article we study the concepts and challenges for automatic design/ reconfiguration of cognitive MANETs. We describe the design objectives, imposed constraints, and involved parameters in MANETs. We describe how cognitive techniques can be employed to exploit the unused spectrum in military architectures. We then discuss the challenges facing the design/reconfiguration of a cognitive network and their implications at different network layers. We also describe possible implementation options for designing MANETs that employ cognitive features at all layers.

Minimum Latency Broadcasting in Multiradio, Multichannel, Multirate Wireless Meshes

Abstract: This paper addresses the problem of "efficientrdquo broadcast in a multiradio, multichannel, multirate wireless mesh network (MR2-MC WMN). In such an MR2-MC WMN, nodes are equipped with multiple radio interfaces, tuned to orthogonal channels, that can dynamically adjust their transmission rate by choosing a modulation scheme appropriate for the channel conditions. We choose "broadcast latency,rdquo defined as the maximum delay between a packet's network-wide broadcast at the source and its eventual reception at all network nodes, as the ldquoefficiencyrdquo metric of broadcast performance. We study in this paper how the availability of multirate transmission capability and multiple radio interfaces tuned to orthogonal channels in MR2-MC WMN nodes can be exploited, in addition to the medium's ldquowireless broadcast advantagerdquo (WBA), to improve the ldquobroadcast latencyrdquo performance. In this paper, we present four heuristic solutions to our considered problem. We present detailed simulation results for these algorithms for an idealized scheduler, as well as for a practical 802.11-based scheduler. We also study the effect of channel assignment on broadcast performance and show that channel assignment can affect the broadcast performance substantially. More importantly, we show that a channel assignment that performs well for unicast does not necessarily perform well for broadcast/multicast.

Methods for efficient organization of vehicle peer groups and efficient v2r communications

Abstract: The present invention provides methods for efficient control message distribution in a VANET. Efficient flooding mechanisms are provided to fulfill the objective of flooding (delivering a message to every connected node) with a limited number of re-broadcasting by selected key nodes. A suppression-based efficient flooding mechanism utilizes a Light Suppression (LS) technique to reduce the number of flooding relays by giving up the broadcasting of a flooding message when a node observes downstream relay of the same flooding message. Additionally, a relay-node based efficient flooding mechanism selects Relay Nodes (RN) to form an efficient flooding tree for control message delivery. RNs are nodes that relay at least one control message, for instance a Membership Report (MR) to the upstream node in “k” previous control message cycles The upstream node may be the group header (GH) for the LPG.

System and method for evaluating multiple connectivity options

Abstract: This present application relates to, among other things, novel techniques to evaluate and qualify multiple networking options. A device contains multiple network connectivity options, including but not limited to various wireless and wired technologies such as Wi-Fi, 3G, WiMAX, LTE, Ethernet, Bluetooth, UWB, WHDMI, etc. Each connectivity option can be evaluation and pre-qualified prior to the user selecting that mode of communication. This evaluation process takes into account both lower-layer information such as signal strength, bit error rates, SNR, interference, etc. but also network-layer information such as IP connectivity, and end-to-end path performance.

Method and system for multi-touch-based browsing of media summarizations on a handheld device

Abstract: The inventive system comprises a touch screen on a mobile device and an application that defines a set of functioning components that provide the functionality for navigating media. The inventive application comprises components including event handling touches on the touch screen, presentation and layout interacting with event handling, content cache storing media and metadata, and content loading connecting to and loading the media and the metadata from a remote storage device, such that the event handling component invokes one or more of the presentation and layout component, the content cache component and the content loading component in response to various touch screen interactions. The various touch screen interactions perform setting a browser shape, setting a range, focus, zoom in and out, and/or level of detail of the media segments, moving laterally in time, resetting a view, annotating and/or viewing annotations, playing, pausing, and stopping the media summarization.

The Beacon Movement Detection Problem in Wireless Sensor Networks for Localization Applications

Abstract: Localization is a critical issue in wireless sensor networks. In most localization systems, beacons are being placed as references to determine the positions of objects or events appearing in the sensing field. The underlying assumption is that beacons are always reliable. In this work, we define a new beacon movement detection (BMD) problem. Assuming that there are unnoticed changes of locations of some beacons in the system, this problem concerns how to automatically monitor such situations and identify such unreliable beacons based on the mutual observations among beacons only. Existence of such unreliable beacons may affect the localization accuracy. After identifying such beacons, we can remove them from the localization engine. Four BMD schemes are proposed to solve the BMD problem. Then, we evaluate how these solutions can improve the accuracy of localization systems in case there are unnoticed movements of some beacons. Simulation results show that our solutions can capture most of the unnoticed beacon movement events and thus can significantly alleviate the degradation of such events.

Bio-inspired topology control for knowledge sharing mobile agents

Abstract: We present different approaches for knowledge sharing bio-inspired mobile agents to obtain a uniform distribution of the nodes over a geographical terrain. In this application, the knowledge sharing agents in a mobile ad hoc network adjust their speed and directions based on genetic algorithms (GAs). With an analytical model, we show that the best fitness value is obtained when the number of neighbors for a mobile agent is equal to the mean node degree. The genetic information that each mobile agent exchanges with other neighboring agents within its communication range includes the node's location, speed, and movement direction. We have implemented a simulation software to study the effectiveness of different GA-based algorithms for network performance metrics including node densities, speed, and number of generations that a GA runs. Compared to random-walk and Hill Climbing approaches, all GA-based cases show encouraging results by converging towards a uniform node distribution.

System and Method for OCDM-Based Photonic Layer Security Robustness to Archival Attack

Abstract: A system and method for transporting encrypted data having a transmitter and a receiver is provided. The transmitter generates a sequence of optical pulses, which are copied and output as identical channels. The identical channels are modulated by a plurality of modulators using data to generate a modulated data signal. Respective spectral phase encoders coupled to each of the plurality of data modulators encode respective modulated data signals using a plurality of mutually orthogonal phase codes that are individually associated with the respective spectral phase encoder. These encoded data signals are combined and code-scrambling by a spectral phase scrambler t using a scramble code as an encryption key to generate an encrypted signal. A receiver reverses the encryption to extract the data.

Intrusion-tolerant group management for mobile ad-hoc networks

Abstract: An inventive system and method for intrusion-tolerant group management for a network is presented. The method comprises a client broadcasting a message request to controllers and validating the rekey messages received from the controllers, and controllers validating the client's broadcast message request and broadcasting proposals, collecting proposals, constructing threshold-signed proofs, updating the view umber, performing the client's message request, generating the rekey based on the valid proposals and transmitting the rekey to the client. Simultaneously, controllers send reconciliation messages to all controllers, based on which the membership state is updated. The client updates a shared key when a predetermined number of valid rekey messages are received. The controllers can communicate via a byzantine fault-tolerant agreement. The client can use its public key to decrypt the rekey and perform validation. The client's message request can be a join or a leave.

Towards a unified architecture for resilience, survivability and autonomic fault-management for self-managing networks

Abstract: The emergence of self-managing networks can be seen as an enabler for increased dependability, reliability and robustness of the network layer. All these features are significant for the services and applications relying on the network infrastructure. This paper explores the links between traditional Fault-Management functions belonging to the management plane and the fundamental network functions for Resilience and Survivability embedded inside the protocol modules of a node/device. This results in an architectural framework that allows nodes/devices to implement the converging aspects of Fault-Management (now becoming autonomic), Resilience and Survivability in a self-managing network. The components and adaptation mechanisms of the proposed framework will make the network layer more robust and application/service aware. Thus, the dependability, reliability, and adaptability of the upper layer services and applications are expected to increase.

ETSI Industry Specification Group on Autonomic Network Engineering for the Self-managing Future Internet (ETSI ISG AFI)

Abstract: The area of Autonomic/Self-Managing Networks is still faced with problems of the lack of harmonized steps and efforts towards the establishment of common Specifications of the architectures and functionalities for Self-Management within Future Networks such as the envisaged Future Internet. Ideally, the harmonization can now be achieved through a newly established and well-focused Special Working Group in ETSI - a world renowned Telecommunications Standardization body. The SpecialWorking Group is an Industry Specification Group (ISG) called "Autonomic network engineering for the self-managing Future Internet (AFI) [4]. The AFI aims to serve as a focal point for the development of common Specifications and engineering frameworks that guarantee interoperability of nodes/devices for Self-managing Future Networks.

Throughput-oriented MAC for mobile ad hoc networks: A game-theoretic approach

Abstract: The conservative nature of the 802.11 channel access scheme has instigated extensive research whose goal is to improve the spatial reuse and/or energy consumption of a mobile ad hoc network. Transmission power control (TPC) was shown to be effective in achieving this goal. Despite their demonstrated performance gains, previously proposed power-controlled channel access protocols often incur extra hardware cost (e.g., require multiple transceivers). Furthermore, they do not fully exploit the potential of power control due to the heuristic nature of power allocation. In this paper, we propose a distributed, single-channel MAC protocol (GMAC) that is inspired by game theory. In GMAC, each transmitter computes a utility function that maximizes the link's achievable throughput. The utility function includes a pricing factor that accounts for energy consumption. GMAC allows multiple potential transmitters to contend through an admission phase that enables them to determine the transmission powers that achieve the Nash equilibrium (NE). Simulation results indicate that GMAC significantly improves the network throughput over the 802.11 scheme and over another single-channel power-controlled MAC protocol (POWMAC). These gains are achieved at no extra energy cost. Our results also indicate that GMAC performs best under high node densities and large data packet sizes.

System and method for determining symantic equivalence between access control lists

Abstract: Aspects of the invention pertain to analyzing and modifying access control lists that are used in computer networks. Access control lists may have many individual rules that indicate whether information can be passed between certain devices in a computer network. The access control lists may include redundant or conflicting rules. An aspect of the invention determines whether two or more access control lists are equivalent or not. Order-dependent access control lists are converted into order-independent access control lists, which enable checking of semantic equivalence of different access control lists. Upon conversion to an order-independent access control list, lower-precedence rules in the order-free list are checked for overlap with a current higher precedence entry. If overlap exists, existing order-free rules are modified so that spinoff rules have no overlap with the current entry. This is done while maintaining semantic equivalence.

Scalable disruptive-resistant communication method

Abstract: A method for transmitting data in vehicular network comprising determining a communication window between at least two nodes, grouping a plurality of fragments of content together into an aggregate fragment block, forwarding the aggregate fragment block to a target node and assembling the plurality of fragments into the content. The content is divided into the plurality of fragments. A fragment signature is generated for the fragments that contain fragment index information regarding each fragment. Each fragment is unambiguously identified by its signature. A number of fragments grouped into the aggregate fragment block is dependent on the communication window.

Multi-interface management configuration method and graphical user interface for connection manager

Abstract: A terminal device includes interfaces that establish links to networks. The networks can be wired, wireless, and the like. The terminal device includes a connection manager that manages the network connections based on configured parameters. Based on the configuration parameters it may compare network performance of different links in the device and it may switch or connect to a link having the best connectivity. Parameters are set to configure the connection manager and how it operates. The parameters can be set via a graphical user interface by the user or alternatively by the operator administrator.