Overall Requirements for Global Information Multimedia Communication Village <Emphasis Type="Italic">10th Strategic Workshop</Emphasis>

The foundations for the definition of the network of the future should be based on a correct user and community characterizations to minimize the fragmentation of the experiences during the global interactions with information communication infrastructures. This paper describes some of the complex objectives and main challenges that telecommunication solution and services have to deal with in order to respect both specific requirements of global user interactions, habits and personalization, and framework requirements about green environments.

A feedback-based congestion control mechanism for labeled optical burst switched networks

In this article we describe a feedback-based OBS network architecture in which core nodes send messages to source nodes requesting them to reduce their transmission rate on congested links. Within this framework, we introduce a new congestion control mechanism called congestion control with explicit reduction request (CCERQ). Through feedback signals, CCERQ proactively attempts to prevent the network from entering the congestion state. Basic building blocks and performance tradeoffs of CCERQ are the main focus of this article.

Providing differentiated services for multi-class traffic in IP/MPLS over WDM networks

Providing differentiated services in IP/MPLS over WDM networks has attracted a lot of recent attention. This article extends the Path Inflation Control (PIC) policy recently proposed by us to provide differentiated services in IP/MPLS over WDM networks with traffic grooming. Three different algorithms are considered for provisioning differentiated services. The simulation results show that, with two of the three algorithms, the network cannot only provide differentiated services when the traffic load is high but also gives significantly lower blocking for the lower priority class traffic and for the overall traffic at low traffic loads.

An integrated view on monitoring and compensation for dynamic optical networks: from management to physical layer

A vertical perspective, ranging from management and routing to physical layer options, concerning dynamic network monitoring and compensation of impairments (M&C), is given. Feasibility, reliability, and performance improvements on reconfigurable transparent networks are expected to arise from the consolidated assessment of network management and control specifications, as a more accurate evaluation of available M&C techniques. In the network layer, physical parameters aware algorithms are foreseen to pursue reliable network performance. In the physical layer, some new M&C methods were developed and rating of the state-of-the-art reported in literature is given. Optical monitoring implementation and viability is discussed.

Design of Power and Area Efficient Digital Down-converters for Broadband Communications Systems

This paper shows that when a digital receiver is designed utilizing two clock scopes, the digital down-converter can be designed to be efficient in terms of area and power consumption. The main design parameter that contributes to make the design efficient is the relationship between the transition band of the designed filter and its sampling frequency.

A Policy-based Approach for Reconfiguration Management and Enforcement in Autonomic Communication Systems

This paper presents an overview of the policy-based reconfiguration management and enforcement for autonomic communication system platform (Pre-meacs). In contrast to existing management approaches, which require static priori policy configurations, policies are created dynamically. The proposed Pre-meacs framework creates new policies at runtime in response to the changing requirements. A hierarchical policy model is used to refine users and administrators’ high-level goals into low-level objectives. The new approach ensures the success of the reconfiguration through monitoring feedback. The main components of Pre-meacs framework for policy creation, storage, evaluation and enforcement are presented, and the procedures of Pre-meacs in networks reconfiguration management are also demonstrated. Illustrative example demonstrates the performance of the proposed framework.

Role of Convergence in GIMCV Development: A Vision

Path to Global Information Multimedia Communication Village (GIMCV) can be seen as a convergence process among telephony, data exchange and television. Convergence refers not only to various services provided by the same operator but also by the same device, the same access network, the same transport network, etc. This paper present authors’ vision on how convergence will lead the GIMCV development.

On the Performance of Broadband Mobile Internet Access System

In this paper, we evaluate the performance of OFDMA/TDD-based broadband mobile internet access system with the features of adaptive modulation & coding (AMC) and hybrid ARQ. We present a framework of system-level simulation and furthermore, intend to derive the insightful results towards understanding the performance of broadband mobile internet access system. The average system throughput as well as delay performance is evaluated for the different channel characteristics and system parameters, which allows for predicting the system capacity in the varying cellular network environment.

A Mapping Framework Based on Packing for Design Space Exploration of Heterogeneous MPSoCs

The computational demand of signal processing algorithms is rising continuously. Heterogeneous embedded multiprocessor systems-on-chips are one solution to satisfy this demand. But to be able to take advantage of these systems, new strategies are required to map applications to such a system and to evaluate the systems performance at a very early design stage. We will present a framework for static, analytical, bottom-up temporal and spatial mapping of applications to MPSoCs based on packing. This mapping framework allows easy performance evaluation and design space exploration of heterogeneous systems on chip.

An Approach to Increase the Lifetime of a Linear Array of Wireless Sensor Nodes

The nodes in a wireless sensor network are generally energy constrained. The lifetime of such a network is limited by the energy dissipated by individual nodes during signal processing and communication with other nodes. The issues of modeling a sensor network and assessment of its lifetime have received considerable attention in recent years. This paper provides an analytical framework for placing a number of nodes in a linear array such that each node dissipates the same energy per data gathering cycle. This approach ensures that all nodes run out of battery energy almost simultaneously. It is shown that the network lifetime almost doubles with the proposed scheme as compared to other reported schemes. However, in practice, the nodes are not expected to be placed as per this theoretical requirement. The issue of random placement of nodes has also been investigated to obtain the statistics of energy consumption of a node. The analytical results for random node placement are validated through simulation studies.

Restoration in wavelength-routed optical networks by means of ant colony optimization

Because of the distributed control of the network, the dynamic nature of the traffic and the unpredictability of a failure event, the flexibility and robustness of ant colony optimization (ACO) make it a suitable candidate for provisioning lightpaths in an optical network. In this work, we propose a fault-tolerant dynamic routing and wavelength assignment (RWA) algorithm based on the ACO framework, presenting its integration into the Generalized multi-protocol label switching (GMPLS) control plane. By simulating two different scenarios, we demonstrate the effectiveness of this algorithm when a single link or node failure occurs.

D-STAR MAC Protocol: A Cross Layer Solution for Wireless Sensor Networks Endowed with Directive Antennas

This paper deals with a novel MAC layer protocol, namely Directive synchronous transmission asynchronous reception (D-STAR), which is able to logically synchronize a Wireless sensor network (WSN). In this case both sleep and active states together with integrating directional antennas within the communications framework can be managed, according to a cross-layer design. D-STAR protocol has been characterized in terms of functional characteristics and the overall performance is presented in terms of network lifetime gain, set-up latency and collision probability. A remarkable gain is shown with respect to the basic approach endowed with omnidirectional antennas without increasing the signaling overhead nor affecting the set up latency, but achieving energy consumption reduction.

Network Virtualization: A Viable Path Towards the Future Internet

New technologies as well as new ways of using network services are rapidly changing the Internet’s landscape. These developments will have far-reaching implications for the architecture of the networks of the future. However, the current Internet design is plagued with a number of fundamental limitations, which makes its use as the sole basis for the networking applications of the future questionable. We believe that the Future Internet must allow the co-existence of diverse network designs and paradigms, both new and old, to remain open to innovation and meet the challenges of the future. In this paper, we propose to use network virtualization, embedded in an architectural framework, to achieve this goal and to lay the foundation for the deployment of novel concepts such as content-centric networking.

A dynamic-clustering reactive routing algorithm for wireless sensor networks

The clustering is a key routing method for large-scale wireless sensor networks, which effective extends the lifetime and the expansibility of network. In this paper, a node model is defined based on the structure and transmission principle of neuron, and a dynamic-clustering reactive routing algorithm is proposed. Once the event emergences, the cluster head is dynamic selected in the incident region according to the residual energy. The data collected by the cluster head is sent back to the Sink along the network backbone. Two kinds of accumulation ways are designed to increase the efficiency of data collection. Meanwhile through the fluctuation of action-threshold, the cluster head can trace the changing speed of incident; the nodes outside the incident region use this fluctuation to send data periodically. Finally, the simulation results verify that the DCRR algorithm extends the network’s lifetime considerably and adapts to the change of network scale. The analysis shows that DCRR has more prominent advantages under low and middle load.

Performance analysis of an improved soft preemptive scheme for unevenly distributed traffic in optical wavelength-division multiplexing networks

In optical wavelength-division multiplexing (WDM) networks, traffic can be unevenly distributed across the network causing inefficient utilization of resources. To solve this problem, an improved soft preemptive (SP) scheme is proposed by considering dynamic resource distribution to deal with the uneven network utilization. A novel unevenly distributed traffic model in cross-time-zone networks is also presented to evaluate the efficiency of the new scheme. Compared with other schemes such as normal shortest path first (SPF) routing and wavelength conversion (WC), the new proposed scheme results demonstrate significantly better performance with respect to the network utilization and overall network blocking probability.

Fast PWM-Based Test for High Resolution ΣΔ ADCs

This work describes a novel test strategy that uses digital stimuli for cheap, fast, though accurate, testing of high resolution ΣΔ ADCs. Simulations and measurements showed a discrimination threshold on specification parameters up to −90 dBc. The proposed method helps to reduce the cost of ADC production test, to extend test coverage and to enable built-in self-test and test-based self-calibration.

Cellular Controlled Short-Range Communication for Cooperative P2P Networking

This article advocates a novel communication architecture and associated collaborative framework for future wireless communication systems. In contrast to the dominating cellular architecture and the upcoming peer-to-peer architecture, the new approach envisions a cellular controlled short-range communication network among cooperating mobile and wireless devices. The role of the mobile device will change, from being an agnostic entity in respect to the surrounding world to a cognitive device. This cognitive device is capable of being aware of the neighboring devices as well as on the possibility to establish cooperation with them. The novel architecture together with several possible cooperative strategies will bring clear benefits for the network and service providers, mobile device manufacturers and also end users.

Improvement of Location Accuracy by Adding Nodes to Ad-Hoc Networks

We discuss the effect of adding nodes on the location accuracy of Ad-Hoc networks. All results are obtained by analyzing the Cramér-Rao Lower bound. We show that for planar network the additional node must have at least 3 connections in order to have any effect on the existing nodes accuracy. Further, we identify the nodes whose accuracy will be improved. Finally, we show that the accuracy cannot be improved without limit by adding more and more nodes to an existing network.

A Tool for Unbiased Comparison between Logarithmic and Floating-point Arithmetic

For applications requiring a large dynamic, real numbers may be represented either in floating-point, or in the logarithm number system (LNS). Which system is best for a given application is difficult to know in advance, because the cost and performance of LNS operators depend on the target accuracy in a highly non linear way. Therefore, a comparison of the pros and cons of both number systems in terms of cost, performance and overall accuracy is only relevant on a per-application basis. To make such a comparison possible, two concurrent libraries of parameterized arithmetic operators, targeting recent field-programmable gate arrays, are presented. They are unbiased in the sense that they strive to reflect the state-of-the-art for both number systems. These libraries are freely available at .

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Multi-access Management in Heterogeneous Networks

Communication networks and mobile devices integrate an increasing number of access technologies. At the same time, new business roles emerge, which lead to new cooperation schemes between access providers providing different types of access connectivity. As a result, a variety of access technologies will be available for users at the same time. In this article we present an architecture and a framework capable of integrating different access systems into a multi-access system and selecting the best suited access for users. A utility-based approach is proposed for the evaluation of different access allocation choices, which is based on user and network policies, the performance of access bearers, and the availability of access resources. We present a general multi-access management framework, which integrates the different multi-access related functions: access detection, access evaluation and access selection, which can then lead to an access handover.