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Showing papers on "Testbed published in 2011"


Proceedings ArticleDOI
30 Aug 2011
TL;DR: This work proposes an architecture that integrates OpenFlow with WMNs and provides such flow-based routing and forwarding capabilities and implemented a simple solution to solve the problem of client mobility in a WMN which handles the fast migration of client addresses.
Abstract: everal protocols for routing and forwarding in Wireless Mesh Networks (WMN) have been proposed, such as AODV, OLSR or B.A.T.M.A.N. However, providing support for e.g. flow-based routing where flows of one source take different paths through the network is hard to implement in a unified way using traditional routing protocols. OpenFlow is an emerging technology which makes network elements such as routers or switches programmable via a standardized interface. By using virtualization and flow-based routing, OpenFlow enables a rapid deployment of novel packet forwarding and routing algorithms, focusing on fixed networks. We propose an architecture that integrates OpenFlow with WMNs and provides such flow-based routing and forwarding capabilities. To demonstrate the feasibility of our OpenFlow based approach, we have implemented a simple solution to solve the problem of client mobility in a WMN which handles the fast migration of client addresses (e.g. IP addresses) between Mesh Access Points and the interaction with re-routing without the need for tunneling. Measurements from a real mesh testbed (KAUMesh) demonstrate the feasibility of our approach based on the evaluation of forwarding performance, control traffic and rule activation time.

311 citations


Journal ArticleDOI
TL;DR: This paper proposes a methodology and presents a working prototype system for automatic detection and resolution of bottlenecks in a multi-tier Web application hosted on a cloud in order to satisfy specific maximum response time requirements.

291 citations


Proceedings ArticleDOI
15 Aug 2011
TL;DR: NetLord provides tenants with simple and flexible network abstractions, by fully and efficiently virtualizing the address space at both L2 and L3, and achieving order-of-magnitude goodput improvements over previous approaches.
Abstract: Providers of "Infrastructure-as-a-Service" need datacenter networks that support multi-tenancy, scale, and ease of operation, at low cost. Most existing network architectures cannot meet all of these needs simultaneously.In this paper we present NetLord, a novel multi-tenant network architecture. NetLord provides tenants with simple and flexible network abstractions, by fully and efficiently virtualizing the address space at both L2 and L3. NetLord can exploit inexpensive commodity equipment to scale the network to several thousands of tenants and millions of virtual machines. NetLord requires only a small amount of offline, one-time configuration. We implemented NetLord on a testbed, and demonstrated its scalability, while achieving order-of-magnitude goodput improvements over previous approaches.

263 citations


Book ChapterDOI
17 Apr 2011
TL;DR: Indriya as mentioned in this paper is a large-scale low-cost wireless sensor network testbed deployed at the National University of Singapore (NU) which uses TelosB devices and it is built on an active-USB infrastructure.
Abstract: This paper presents Indriya, a large-scale, low-cost wireless sensor network testbed deployed at the National University of Singapore. Indriya uses TelosB devices and it is built on an active-USB infrastructure. The infrastructure acts as a remote programming back-channel and it also supplies electric power to sensor devices. Indriya is designed to reduce the costs of both deployment and maintenance of a large-scale testbed. Indriya has been in use by over 100 users with its maintenance incurring less than US$500 for almost 2 years of its usage.

232 citations


Journal ArticleDOI
01 Jan 2011
TL;DR: The results reveal that MP-OLSR is suitable for mobile, large and dense networks with large traffic, and could satisfy critical multimedia applications with high on time constraints.
Abstract: Multipath routing protocols for Mobile Ad hoc NETwork (MANET) address the problem of scalability, security (confidentiality and integrity), lifetime of networks, instability of wireless transmissions, and their adaptation to applications. Our protocol, called MultiPath OLSR (MP-OLSR), is a multipath routing protocol based on OLSR [1]. The Multipath Dijkstra Algorithm is proposed to obtain multiple paths. The algorithm gains great flexibility and extensibility by employing different link metrics and cost functions. In addition, route recovery and loop detection are implemented in MP-OLSR in order to improve quality of service regarding OLSR. The backward compatibility with OLSR based on IP source routing is also studied. Simulation based on Qualnet simulator is performed in different scenarios. A testbed is also set up to validate the protocol in real world. The results reveal that MP-OLSR is suitable for mobile, large and dense networks with large traffic, and could satisfy critical multimedia applications with high on time constraints.

187 citations


Proceedings ArticleDOI
09 May 2011
TL;DR: This work extends the classic control problem of the inverted pendulum by placing the pendulum on top of a quadrotor aerial vehicle, using a ‘Virtual Body Frame’ for the time-invariant description of curved trajectories.
Abstract: We extend the classic control problem of the inverted pendulum by placing the pendulum on top of a quadrotor aerial vehicle. Both static and dynamic equilibria of the system are investigated to find nominal states of the system at standstill and on circular trajectories. Control laws are designed around these nominal trajectories. A yaw-independent description of quadrotor dynamics is introduced, using a ‘Virtual Body Frame’. This allows for the time-invariant description of curved trajectories. The balancing performance of the controller is demonstrated in the ETH Zurich Flying Machine Arena testbed. Development potential for the future is highlighted, with a focus on applying learning methodology to increase performance by eliminating systematic errors that were seen in experiments.

177 citations


Journal ArticleDOI
TL;DR: The concept of independent component analysis in combination with the robust principal component analysis technique is employed to recover data from the simultaneous smart meter wireless transmissions in the presence of strong wideband interference.
Abstract: This paper systematically investigates the novel idea of applying the next generation wireless technology, cognitive radio network, for the smart grid. In particular, system architecture, algorithms, and hardware testbed are studied. A microgrid testbed supporting both power flow and information flow is also proposed. Control strategies and security considerations are discussed. Furthermore, the concept of independent component analysis (ICA) in combination with the robust principal component analysis (PCA) technique is employed to recover data from the simultaneous smart meter wireless transmissions in the presence of strong wideband interference. The performance illustrates the gain of bringing the state of the art mathematics to smart grid.

170 citations


Proceedings ArticleDOI
09 Nov 2011
TL;DR: An overview of the MobilityFirst network architecture is presented, which is a clean-slate project being conducted as part of the NSF Future Internet Architecture (FIA) program, intended to directly address the challenges of wireless access and mobility at scale, while also providing new multicast, anycast, multi-path and context-aware services needed for emerging mobile Internet application scenarios.
Abstract: This short paper presents an overview of the MobilityFirst network architecture, which is a clean-slate project being conducted as part of the NSF Future Internet Architecture (FIA) program. The proposed architecture is intended to directly address the challenges of wireless access and mobility at scale, while also providing new multicast, anycast, multi-path and context-aware services needed for emerging mobile Internet application scenarios. Key protocol components of the proposed architecture are: (a) separation of naming from addressing; (b) public key based self-certifying names (called globally unique identifiers or GUIDs) for network-attached objects; (c) global name resolution service (GNRS) for dynamic name-to-address binding; (d) delay-tolerant and storage-aware routing (GSTAR) capable of dealing with wireless link quality fluctuations and disconnections; (e) hop-by-hop transport of large protocol data units; and (f) location or context-aware services. The basic operations of a MobilityFirst router are outlined. This is followed by a discussion of ongoing proof-of-concept prototyping and experimental evaluation efforts for the MobilityFirst protocol stack. In conclusion, a brief description of an ongoing multi-site experimental deployment of the MobilityFirst protocol stack on the GENI testbed is provided.

168 citations


Proceedings ArticleDOI
29 Apr 2011
TL;DR: A testbed designed to study and simulate the various available techniques for securing and protecting Supervisory Control and Data Acquisition (SCADA) systems against a wide range of cyber attacks is presented.
Abstract: The critical infrastructures of our society are in the process of being modernized. Most significantly impacted are the industrial control systems through replacement of old electromechanical systems with advanced computing and communication technologies. This modernization has introduced new vulnerabilities to those infrastructures. Securing critical infrastructures is a challenging research problem, as these control systems were not designed with security in mind. This paper presents a testbed designed to study and simulate the various available techniques for securing and protecting Supervisory Control and Data Acquisition (SCADA) systems against a wide range of cyber attacks. The testbed is also used to evaluate the detection rate, false alerts and effectiveness of the protection techniques. We present preliminary results on using the testbed to detect a selected set of cyber attacks and the impact of the protection techniques on the operations of the system.

161 citations


Journal ArticleDOI
TL;DR: The testbed enables a research process in which cybersecurity vulnerabilities are discovered, exploits are used to understand the implications of the vulnerability on controlled physical processes, identified problems are classified by criticality and similarities in type and effect, and finally cybersecurity mitigations are developed and validated against within the testbed.

159 citations


Proceedings ArticleDOI
Xiaoying Bai1, Muyang Li1, Bin Chen1, Wei-Tek Tsai1, Jerry Gao1 
12 Dec 2011
TL;DR: The paper investigates the new architecture and techniques for designing testing tools for the cloud and in the cloud, and identifies the needs for cloud testing tools including multi-layer testing, SLA-based testing, large scale simulation, and on-demand test environment.
Abstract: Cloud platform provides an infrastructure for resource sharing, software hosting and service delivering in a pay-per-use approach. To test the cloud-based software systems, techniques and tools are necessary to address unique quality concerns of the cloud infrastructure such as massive scalability and dynamic configuration. The tools can also be built on the cloud platform to benefit from virtualized platform and services, massive resources, and parallelized execution. The paper makes a survey of representative approaches and typical tools for cloud testing. It identifies the needs for cloud testing tools including multi-layer testing, SLA-based testing, large scale simulation, and on-demand test environment. To address the needs, it investigates the new architecture and techniques for designing testing tools for the cloud and in the cloud. Tool implementations are surveyed considering different approaches including migrated conventional tools, research tools, commercial tools and facilities like benchmark and testbed. Based on the analysis of state-of-the-art practices, the paper further investigates future trend of testing tool research and development from both capability and usability perspectives.

Journal ArticleDOI
TL;DR: A dynamic strategy to manage the energy in the hybrid electric vehicle is introduced that uses a fuzzy logic controller and considers the slow dynamics in the FCS, the vehicle speed, and the state of charge in the supercapacitors.
Abstract: The aim of this paper is to present the practical control structure (PCS) and energy management strategy of a testbed hybrid electric vehicle (HEV). This vehicle is equipped with batteries, a supercapacitor system, and a fuel cell system (FCS). The PCS, based on the energetic macroscopic representation methodology, is used to evaluate and compare the different energy management strategies to be implemented in the vehicle. This paper introduces a dynamic strategy to manage the energy in the hybrid electric vehicle; this strategy uses a fuzzy logic controller and considers the slow dynamics in the FCS, the vehicle speed, and the state of charge in the supercapacitors.

Proceedings ArticleDOI
05 Jun 2011
TL;DR: This paper implements a set of storage management techniques in the open source CCNx prototype and performs extensive experiments in a real testbed under fairly realistic network conditions, allowing to clarify the relation between CCN chunk-level caching and Quality of Experience (QoE) perceived by end users.
Abstract: Content-Centric Networking is a new communication architecture that rethinks the Internet communication model, designed for point-to-point connections between hosts, and centers it around content dissemination and retrieval. Most of the issues faced by the current IP infrastructure in terms of mobility management, security, scalability, which are accrued by today's Internet trends, find a natural solution in CCN shift from IP addresses to named data. In this paper we explore the impact of storage management on the performance of multiple applications sharing the same CCN infrastructure and we quantify the effectiveness of static storage partitioning and dynamic management techniques in providing service differentiation. To this purpose, we implement a set of storage management techniques in the open source CCNx prototype and perform extensive experiments in a real testbed under fairly realistic network conditions. Our experimental results allow to clarify the relation between CCN chunk-level caching and Quality of Experience (QoE) perceived by end users.

Proceedings ArticleDOI
10 Apr 2011
TL;DR: This work proposes a novel approach for mobile users to collect the network-wide data by only performing a local modification to update the routing structure while the routing performance is bounded and controlled compared to the optimal performance.
Abstract: We study the ubiquitous data collection for mobile users in wireless sensor networks. People with handheld devices can easily interact with the network and collect data. We propose a novel approach for mobile users to collect the network-wide data. The routing structure of data collection is additively updated with the movement of the mobile user. With this approach, we only perform a local modification to update the routing structure while the routing performance is bounded and controlled compared to the optimal performance. The proposed protocol is easy to implement. Our analysis shows that the proposed approach is scalable in maintenance overheads, performs efficiently in the routing performance, and provides continuous data delivery during the user movement. We implement the proposed protocol in a prototype system and test its feasibility and applicability by a 49-node testbed. We further conduct extensive simulations to examine the efficiency and scalability of our protocol with varied network settings.

Journal ArticleDOI
01 Aug 2011
TL;DR: A standardized process for industrial wireless network technologies and then introduces network composition, network topology, protocol stack architecture, and some key protocol technologies of WIA-PA, which is an international specification of industrial wireless networks for process automation.
Abstract: Wireless process control has been a popular topic recently in the field of industrial control. In the industrial field, wireless technologies are considered despite the lack of an ideal industrial wireless standard. However, application development of industrial wireless networks is slow due to the lack of an ideal standard. Open standards are the foundation of industrial wireless application extensions. This paper first summarizes a standardized process for industrial wireless network technologies and then introduces network composition, network topology, protocol stack architecture, and some key protocol technologies of WIA-PA, which is an international specification of industrial wireless networks for process automation. Furthermore, a comparison between WIA-PA and other main industrial wireless network specifications like WirelessHART and ISA100.11a is provided. Architecture and key technologies of a WIA-PA are also introduced. Our first-hand experiences in developing WIA-PA testbed based on the modularization method are given. Finally, experiment results illustrate the performance and efficiency of WIA-PA. Copyright © 2010 John Wiley & Sons, Ltd. (This paper first summarizes a standardized process for industrial wireless network technologies and then introduces network composition, network topology, protocol stack architecture, and some key protocol technologies of WIA-PA, which is an international specification of industrial wireless networks for process automation. Our first-hand experiences in developing WIA-PA testbed based on the modularization method are given. Finally, experiment results illustrate the performance and efficiency of WIA-PA.)

Journal ArticleDOI
TL;DR: To the authors' knowledge, this protocol is the first that makes use of the diversity in data traffic while considering latency, reliability, residual energy in sensor nodes, and transmission power between nodes to cast QoS metrics as a multiobjective problem.
Abstract: A new localized quality of service (QoS) routing protocol for wireless sensor networks (WSN) is proposed in this paper. The proposed protocol targets WSN's applications having different types of data traffic. It is based on differentiating QoS requirements according to the data type, which enables to provide several and customized QoS metrics for each traffic category. With each packet, the protocol attempts to fulfill the required data-related QoS metric(s) while considering power efficiency. It is modular and uses geographical information, which eliminates the need of propagating routing information. For link quality estimation, the protocol employs distributed, memory and computation efficient mechanisms. It uses a multisink single-path approach to increase reliability. To our knowledge, this protocol is the first that makes use of the diversity in data traffic while considering latency, reliability, residual energy in sensor nodes, and transmission power between nodes to cast QoS metrics as a multiobjective problem. The proposed protocol can operate with any medium access control (MAC) protocol, provided that it employs an acknowledgment (ACK) mechanism. Extensive simulation study with scenarios of 900 nodes shows the proposed protocol outperforms all comparable state-of-the-art QoS and localized routing protocols. Moreover, the protocol has been implemented on sensor motes and tested in a sensor network testbed.

Proceedings ArticleDOI
12 Nov 2011
TL;DR: This paper introduces an approach that leverages virtual machine (VM) disk-image multi-snapshotting and multi-deployment inside checkpoint-restart protocols running at guest level in order to efficiently capture and potentially roll back the complete state of the application, including file system modifications.
Abstract: Infrastructure-as-a-Service (IaaS) cloud computing is gaining significant interest in industry and academia as an alternative platform for running scientific applications. Given the dynamic nature of IaaS clouds and the long runtime and resource utilization of such applications, an efficient checkpoint-restart mechanism becomes paramount in this context. This paper proposes a solution to the aforementioned challenge that aims at minimizing the storage space and performance overhead of checkpoint-restart. We introduce an approach that leverages virtual machine (VM) disk-image multi-snapshotting and multi-deployment inside checkpoint-restart protocols running at guest level in order to efficiently capture and potentially roll back the complete state of the application, including file system modifications. Experiments on the G5K testbed show substantial improvement for MPI applications over existing approaches, both for the case when customized checkpointing is available at application level and the case when it needs to be handled at process level.

Journal ArticleDOI
TL;DR: To achieve the increase in computational power and data archiving needs required for high-temporal-resolution sampling, the signal processor was upgraded to a scalable, Linux-based cluster with a distributed computing architecture.
Abstract: Since 2007 the advancement of the National Weather Radar Testbed Phased-Array Radar (NWRT PAR) hardware and software capabilities has been supporting the implementation of high-temporal-resolution (∼1 min) sampling. To achieve the increase in computational power and data archiving needs required for high-temporal-resolution sampling, the signal processor was upgraded to a scalable, Linux-based cluster with a distributed computing architecture. The development of electronic adaptive scanning, which can reduce update times by focusing data collection on significant weather, became possible through functionality added to the radar control interface and real-time controller. Signal processing techniques were implemented to address data quality issues, such as artifact removal and range-and-velocity ambiguity mitigation, absent from the NWRT PAR at its installation. The hardware and software advancements described above have made possible the development of conventional and electronic scanning capabil...

Proceedings ArticleDOI
21 Dec 2011
TL;DR: WaterWiSe@SG as mentioned in this paper is a wireless sensor network to enable real-time monitoring of a water distribution network in Singapore, which is designed for high data rate, on-line monitoring of hydraulic parameters within a large urban water distribution system, and the development of systems to enable remote detection of leaks and prediction of pipe burst events.
Abstract: This paper describes the development of WaterWiSe@SG, a wireless sensor network to enable real-time monitoring of a water distribution network in Singapore. The overall project is directed towards three main goals: 1) the application of a low cost wireless sensor network for high data rate, on-line monitoring of hydraulic parameters within a large urban water distribution system; 2) the development of systems to enable remote detection of leaks and prediction of pipe burst events; 3) the integrated monitoring of hydraulic and water quality parameters. In this paper we will describe the current state of the WaterWiSe@SG testbed, and report on experimentation we have performed with respect to leak detection and localization. Furthermore, we describe how we have assimilated real time pressure and flow measurements from the sensor network into hydraulic models that are used to improve state estimation for the network. Finally, we discuss the future plans for the project.

Proceedings ArticleDOI
01 Nov 2011
TL;DR: This work presents two complete and interoperable implementations of the IPv6 protocol stack for LLNs, one for Contiki and one for TinyOS, and shows that the cost of interoperability is low: their performance and overhead is on par with state-of-the-art protocol stacks custom built for the two platforms.
Abstract: Interoperability is essential for the commercial adoption of wireless sensor networks. However, existing sensor network architectures have been developed in isolation and thus interoperability has not been a concern. Recently, IP has been proposed as a solution to the interoperability problem of low-power and lossy networks (LLNs), considering its open and standards-based architecture at the network, transport, and application layers. We present two complete and interoperable implementations of the IPv6 protocol stack for LLNs, one for Contiki and one for TinyOS, and show that the cost of interoperability is low: their performance and overhead is on par with state-of-the-art protocol stacks custom built for the two platforms. At the same time, extensive testbed results show that the ensemble performance of a mixed network with nodes running the two interoperable stacks depends heavily on implementation decisions and parameters set at multiple protocol layers. In turn, these results argue that the current industry practice of interoperability testing does not cover the crucial topic of the performance and motivate the need for generic techniques that quantify the performance of such networks and configure their run-time behavior.

Proceedings Article
01 Jan 2011
TL;DR: This work proposes using machine learning techniques to address the issue of detecting anomalous events or actions in smart environment datasets using real-world sensor data captured from a smart home testbed.
Abstract: The need to have a secure lifestyle at home is in demand more than ever. Today's home is more than just four walls and a roof. Technology at home is on the rise and the place for smart home solutions is growing. One of the major concerns for smart home systems is the capability of adapting to the user. Personalizing the behavior of the home may provide improved comfort, control, and safety. One of the challenges of this goal is tackling anomalous events or actions. This work proposes using machine learning techniques to address this issue of detecting anomalous events or actions in smart environment datasets. The approaches are validated using real-world sensor data captured from a smart home testbed.

Journal ArticleDOI
01 Jul 2011
TL;DR: An integrated framework called NetTopo is presented for providing both simulation and visualization functions to assist the investigation of algorithms in WSNs and provides a common virtual WSN for the purpose of interaction between sensor devices and simulated virtual nodes.
Abstract: Network simulators are necessary for testing algorithms of large scale wireless sensor networks (WSNs), but lack the accuracy of real-world deployments. Deploying real WSN testbed provides a more realistic test environment, and allows users to get more accurate test results. However, deploying real testbed is highly constrained by the available budget when the test needs a large scale WSN environment. By leveraging the advantages of both network simulator and real testbed, an approach that integrates simulation environment and testbed can effectively solve both scalability and accuracy issues. Hence, the simulation of virtual WSN, the visualization of real testbed, and the interaction between simulated WSN and testbed emerge as three key challenges. In this paper, we present an integrated framework called NetTopo for providing both simulation and visualization functions to assist the investigation of algorithms in WSNs. NetTopo provides a common virtual WSN for the purpose of interaction between sensor devices and simulated virtual nodes. Two case studies are described to prove the effectiveness of NetTopo.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed an Android/OSGi platform for vehicular telematics applications, which includes remote management, rich class-sharing, proprietary vehicular applications, security policies, easy management of Application Programming Interface (APIs), and an open environment.

Proceedings Article
08 Aug 2011
TL;DR: The design of ExperimenTor is presented, a large-scale Tor network emulation toolkit and testbed, and the early experiences with prototype testbeds currently deployed at four research institutions are reported.
Abstract: Tor is one of the most widely-used privacy enhancing technologies for achieving online anonymity and resisting censorship. Simultaneously, Tor is also an evolving research network on which investigators perform experiments to improve the network's resilience to attacks and enhance its performance. Existing methods for studying Tor have included analytical modeling, simulations, small-scale network emulations, small-scale PlanetLab deployments, and measurement and analysis of the live Tor network. Despite the growing body of work concerning Tor, there is no widely accepted methodology for conducting Tor research in a manner that preserves realism while protecting live users' privacy. In an effort to propose a standard, rigorous experimental framework for conducting Tor research in a way that ensures safety and realism, we present the design of ExperimenTor, a large-scale Tor network emulation toolkit and testbed. We also report our early experiences with prototype testbeds currently deployed at four research institutions.

Proceedings ArticleDOI
03 Nov 2011
TL;DR: A flexible-bandwidth network testbed with a real-time adaptive control plane that adjusts modulation format and spectrum-positioning to maintain QoS and high spectral efficiency is demonstrated.
Abstract: We demonstrate a flexible-bandwidth network testbed with a real-time adaptive control plane that adjusts modulation format and spectrum-positioning to maintain QoS and high spectral efficiency. A low-speed supervisory channel and FPGAs enable real-time impairment detection.

Proceedings ArticleDOI
12 Oct 2011
TL;DR: The testbed enables a research process in which cybersecurity vulnerabilities are discovered, exploits are used to understand the implications of the vulnerability on controlled physical processes, identified problems are classified by criticality and similarities in type and effect, and finally cybersecurity mitigations are developed and validated against the testbed.
Abstract: This paper describes the Mississippi State University Supervisory Control and Data Acquisition (SCADA) security laboratory and Power and Energy Research laboratory. This laboratory combines process control systems from multiple critical infrastructure industries to create a testbed with functional physical processes controlled by commercial hardware and software over common industrial control system routable and non-routable networks. The testbed enables a research process in which cybersecurity vulnerabilities are discovered, exploits are used to understand the implications of the vulnerability on controlled physical processes, identified problems are classified by criticality and similarities in type and effect, and finally cybersecurity mitigations are developed and validated against the testbed. The testbed also enables control system security workforce development through integration into the classroom of laboratory exercises, functional demonstrations, and research outcomes.

Journal ArticleDOI
TL;DR: It is shown that it is actually possible to reliably discriminate between different P2P-TV applications by simply counting packets, and this classification framework, which uses Support Vector Machines, accurately identifies P1-TV traffic as well as traffic that is generated by other kinds of applications, so that the number of false classification events is negligible.

Proceedings ArticleDOI
19 Sep 2011
TL;DR: XPRESS is presented, a cross-layer backpressure architecture designed to reach the full capacity of wireless multi-hop networks, instead of a collection of poorly coordinated wireless routers, which turns a mesh network into a wireless switch.
Abstract: Contemporary wireless multi-hop networks operate much below their capacity due to the poor coordination among transmitting nodes In this paper we present XPRESS, a cross-layer backpressure architecture designed to reach the full capacity of wireless multi-hop networks Instead of a collection of poorly coordinated wireless routers, XPRESS turns a mesh network into a wireless switch Transmissions over the network are scheduled using a throughput-optimal backpressure algorithm Realizing this theoretical concept entails several challenges, which we identify and address with a cross-layer design and implementation on top of our wireless hardware platform In contrast to previous work, we implement and evaluate backpressure scheduling over a TDMA MAC protocol, as it was originally proposed in theory Our experiments in an indoor testbed show that XPRESS can yield up to 128% throughput gains over 80211

Journal ArticleDOI
TL;DR: The system architecture of the testbed deployed on a real street along with the preliminary experiments are described and the open challenges and research directions on designing a future intelligent road lighting system are discussed.
Abstract: Traditional road lighting systems are outdated and should be replaced with systems which can sense their environment, i.e., users and their consumer electronics (CE) devices, and react intelligently. Realizing such a system requires an interdisciplinary approach which analyzes the efficient system architecture and communication technology while taking into account the user needs. To understand these necessities, subjective experiments should be conducted in a practical testbed, similar to ours. In this paper, we first present the state-of-the-art solutions in the literature. Then, we describe the system architecture of our testbed deployed on a real street along with the preliminary experiments. Finally, we discuss the open challenges and research directions on designing a future intelligent road lighting system.

Journal ArticleDOI
01 Sep 2011
TL;DR: The RadiaLE framework is described, which enables the experimental assessment, design and optimization of LQEs, and a methodology that allows to properly set different types of links and different type of traffic, and to collect rich link measurements, is proposed.
Abstract: Stringent cost and energy constraints impose the use of low-cost and low-power radio transceivers in large-scale wireless sensor networks (WSNs). This fact, together with the harsh characteristics of the physical environment, requires a rigorous WSN design. Mechanisms for WSN deployment and topology control, MAC and routing, resource and mobility management, greatly depend on reliable link quality estimators (LQEs). This paper describes the RadiaLE framework, which enables the experimental assessment, design and optimization of LQEs. RadiaLE comprises (i) the hardware components of the WSN testbed and (ii) a software tool for setting-up and controlling the experiments, automating link measurements gathering through packets-statistics collection, and analyzing the collected data, allowing for LQEs evaluation. We also propose a methodology that allows (i) to properly set different types of links and different types of traffic, (ii) to collect rich link measurements, and (iii) to validate LQEs using a holistic and unified approach. To demonstrate the validity and usefulness of RadiaLE, we present two case studies: the characterization of low-power links and a comparison between six representative LQEs. We also extend the second study for evaluating the accuracy of the TOSSIM 2 channel model.