Showing papers in "Journal of Communications in 2011"

Wireless Sensor Networks: a Survey on Environmental Monitoring

Abstract: Traditionally, environmental monitoring is achieved by a small number of expensive and high precision sensing unities. Collected data are retrieved directly from the equipment at the end of the experiment and after the unit is recovered. The implementation of a wireless sensor network provides an alternative solution by deploying a larger number of disposable sensor nodes. Nodes are equipped with sensors with less precision, however, the network as a whole provides better spatial resolution of the area and the users can have access to the data immediately. This paper surveys a comprehensive review of the available solutions to support wireless sensor network environmental monitoring applications.

The Web of Things: A Survey (Invited Paper)

Abstract: In the vision of the Internet of Things (IoT), an increasing number of embedded devices of all sorts (e.g., sensors, mobile phones, cameras, smart meters, smart cars, traffic lights, smart home appliances, etc.) are now capable of communicating and sharing data over the Internet. Although the concept of using embedded systems to control devices, tools and appliances has been proposed for almost decades now, with every new generation, the ever-increasing capabilities of computation and communication pose new opportunities, but also new challenges. As IoT becomes an active research area, different methods from various points of view have been explored to promote the development and popularity of IoT. One trend is viewing IoT as Web of Things (WoT) where the open Web standards are supported for information sharing and device interoperation. By penetrating smart things into existing Web, the conventional web services are enriched with physical world services. This WoT vision enables a new way of narrowing the barrier between virtual and physical worlds.In this paper, we elaborate the architecture and some key enabling technologies of WoT. Some pioneer open platforms and prototypes are also illustrated. The most recent research results are carefully summarized. Furthermore, many systematic comparisons are made to provide the insight in the evolution and future of WoT. Finally, we point out some open challenging issues that shall be faced and tackled by research community.

Power Saving and Energy Optimization Techniques for Wireless Sensor Neworks (Invited Paper)

Abstract: Wireless sensor networks have become increasingly popular due to their wide range of applications. Energy consumption is one of the biggest constraints of the wireless sensor node and this limitation combined with a typical deployment of large number of nodes have added many challenges to the design and management of wireless sensor networks. They are typically used for remote environment monitoring in areas where providing electrical power is difficult. Therefore, the devices need to be powered by batteries and alternative energy sources. Because battery energy is limited, the use of different techniques for energy saving is one of the hottest topics in WSNs. In this work, we present a survey of power saving and energy optimization techniques for wireless sensor networks, which enhances the ones in existence and introduces the reader to the most well known available methods that can be used to save energy. They are analyzed from several points of view: Device hardware, transmission, MAC and routing protocols.

Distributed and Dynamic Mobility Management in Mobile Internet: Current Approaches and Issues

Abstract: Cellular networks have been hierarchical so that mobility management have primarily been deployed in a centralized architecture. More flattened network architecture for the mobile Internet is anticipated to meet the needs of rapidly increasing traffic from the mobile users and to reduce cost in the core network. Distributing the mobility management functions as opposed to centralizing them at the root of the network hierarchy is more compatible with a flat network architecture. Mobility management may be distributed at different levels: core level, access router level, access level, and host level. It may also be partially distributed or fully distributed. A distributed mobility management architecture avoids unnecessarily long routes, is more scalable with the increasing number of mobile users, and is a convenient platform for dynamic mobility management which means providing mobility support to mobile users only when they need the support. Dynamic mobility management can avoid waste of resources and also reduce signaling overhead and network cost. The desired distributed and dynamic mobility management needs to solve existing problems, meet the needs of changes in traffic and network architecture, and be simple and inexpensive to deploy. This paper surveys existing mobility management solutions in mobile Internet, explains the limitations of a centralized mobility management approach, and discusses potential approaches of distributing mobility management functions. The issues and challenges in the design of distributed and dynamic mobility management are also described.

Cloud computing:architecture and key technologies

Abstract: Based on the analysis and summary of the previous work,the cloud computing framework can be divided into three layers:core cloud services,cloud service management and user access interface.To realize low-cost,reliable,available and scalable cloud services,the up-to-date key technologies and research progresses of the three layers within the cloud framework are reviewed intensively and extensively.Regarding cloud infrastructure,the strategies for data cen-ter design and management are introduced together with the virtualization technology.In respect of large-scale data proc-essing,several platforms and their resource management and task scheduling mechanisms are investigated extensively.With regard to cloud service quality,both QoS guarantee and security/privacy protection are discussed in depth.The prospects for future research are further explored based on the new application models and limitations of cloud comput-ing.Finally,the cloud computing platform and research work of Southeast University are introduced.

A Hybrid Satellite-Terrestrial Cooperative Network over Non Identically Distributed Fading Channels

Abstract: This paper investigates a hybrid satellite-terrestrial cooperative relaying communications network (HSTCN) under independent and non-identical shadowed Rician and Nakagami-m fading channels. It evaluates the performance of such a network using amplify-and-forward (AF) cooperative relaying protocol. The maximal ratio combining (MRC) technique is used at the destination to combine the signals received from the source and cooperating relay nodes. An analytical approach is derived to evaluate the performance of the system in terms of outage probability and symbol error rate (SER). The closed form expressions for the probability density function (PDF), cumulative distribution function (CDF) and moment generating function (MGF) of the end-to-end signal to noise ratio (SNR) are also derived. The derived analytical expressions are applied to the general operating conditions with the help of satellite channel data available from the literature. The analytical results are compared with Monte Carlo simulations. The results show the improvement in the performance of the HSTCN under challenging fading conditions with the help of fixed multiple terrestrial relay nodes.

Energy Efficiency in Ethernet Passive Optical Networks (EPONs): Protocol Design and Performance Evaluation

Abstract: As concerns about energy consumption grow,the power consumption of the EPON becomes a matterof increasing importance. In respect of energy efficiency,the current standard has no management protocols aimingto reduce power consumption in EPONs. In this paper,we propose an Energy Management Mechanism (EMM)for downlink EPON systems. The proposed mechanism isdesigned to enhance the standardized control scheme inEPON with the objective to increase energy efficiency whilesatisfying diverse QoS requirements. The main idea is toput an Optical Network Unit (ONU) into the sleep modeand determine a suitable wakeup time scheduler at theOptical Line Terminal (OLT). A generic EPON system isconsidered, which is composed of an OLT and several ONUsthat are EMM enabled. An energy consumption optimizationproblem aimed at saving energy is proposed and twoheuristic sleep mode scheduling policies are addressed tosolve it. The scheduling algorithms are tightly coupled withthe upstream bandwidth allocation and downstream transmissionscheduling together through an integrated approachin which awake time in ONUs is minimized. There is atrade-off decision between maximizing the power saving andguaranteeing the network performance at the same time.Simulation results show that an EMM-based EPON withwell designed scheduling disciplines is essential to achievingsignificant energy saving while meeting the delay constraint.

Design and Analysis of Relay-aided Broadcast using Binary Network Codes

Abstract: We consider a base-station broadcasting a set of order-insensitive packets to a user population over packet-erasure channels. To improve efficiency we propose relay-aided transmission using instantaneously-decodable binary network coding. The proposed coding schemes have the benefits of minimal decoding delay and low complexity. We further analyze the performance of the resulting broadcast schemes, and show that significant improvements in transmission efficiency are obtained as compared to previously proposed ARQ and network-coding-based schemes.

Security in Mobile Wireless Sensor Networks – A Survey

Abstract: Thanks to recent advances in robotics, sensors and wireless communications, it is feasible to develop a variety of new architectures for Mobile Wireless Sensor Networks (MWSNs) that play an important role in various applications such as battlefield surveillance, harbor monitoring, etc. However, due to the dynamic of mobile network topology in MWSNs, many new security challenges have emerged. In this article, we give a survey on the state of the art technologies in security aspects of MWSNs. We review existing work that provides security in MWSNs, with an emphasis on data survival, forward secrecy, backward secrecy, authentication, and methods for sensor capture detection. Furthermore, in order to stimulate the exploration of new research areas, we point out a few open research topics that can be further pursued, and also shed light on these topics.

Secure Localization in Wireless Sensor Networks: A Survey (Invited Paper)

Abstract: Secure localization of unknown nodes in a Wireless Sensor Network (WSN) is an important research subject. When WSNs are deployed in hostile environments, many attacks happen, e.g., wormhole, sinkhole and sybil attacks. Two issues about unknown nodes’ secure localization need to be considered. First, the attackers may disguise as or attack the unknown and anchor nodes to interfere with localization process. Second, the attackers may forge, modify or replay localization information to make the estimated positions incorrect. Currently, researchers have proposed many techniques, e.g., SeRLoc, HiRLoc and ROPE, to solve the two issues. In this paper we describe the common attacks against localization, and survey research state of secure localization.

Green Communications: A Call for Power Efficient Wireless Systems

Abstract: Telecommunication usage has skyrocketed in recent years and will continue to grow as developing world reaches to wireless as the communication medium of choice. The telecommunications world is only now addressing the significant environmental impact it is creating as well as the incredible cost on power usage. This realization has led to a push towards Green Communications that strives for improving energy efficiency as well as energy independence of telecommunications. A survey of existing metrics for energy efficiency is discussed with specific adaptations for a communication centric viewpoint. This paper reviews recent energy efficient advances made at specific point within the communications cycle such as components, network operation and topology, and incorporating renewable and alternative energy into base stations. We further survey several holistic approaches that illustrate the dependencies between layers of the communications stack and operation/deployment. These approaches include cross layer design, cognitive radio, and wireless distributed computing.

IKM -- An Identity based Key Management Scheme for Heterogeneous Sensor Networks

Abstract: Wireless sensor networks applications are growing and so are their security needs. However, due to severe memory, computing and communication limitations, wireless sensor networks security presents tremendous challenges. Central to any security service, key management is a fundamental cryptographic primitive to provide other security operations. In this paper, we propose IKM, an identity based key management scheme designed for heterogeneous sensor networks. This scheme provides a high level of security as it is based on a variant of public key cryptography named pairing identity based cryptography. The IKM scheme supports the establishment of two types of keys, pairwise key to enable point to point communication between pairs of neighbouring nodes, and cluster key to make in-network processing feasible in each cluster of nodes. IKM also supports the addition of new nodes and re-keying mechanism. A security analysis is presented to prove the scheme resilience against several types of attacks especially the node compromise attack. We also perform an overhead analysis of the proposed scheme in terms of storage, communication, and computation requirements. To demonstrate the feasibility of this scheme, we present implementation and performance evaluation of the proposed scheme on Crossbow TelosB motes running TinyOS. The results indicate that it can be deployed efficiently in resource-constrained sensor networks that need a high level of security.

A Reliable Routing Scheme for Post-Disaster Ad Hoc Communication Networks

Abstract: The natural or man-made disaster demands an efficient communication and coordination among first responders for successful emergency management operations. During emergency situations such as an earthquake or a flood, the traditional telecommunication infrastructure may be damaged and may not provide adequate communication services to emergency management teams. Mobile ad hoc networks are used in such type of situations for exchanging emergency related information. During emergency situation, the deployed ad hoc communication network may itself be prone to failures and vulnerable to malicious threats. The first responders use real-time applications for exchanging emergency related information, which may create network congestion. The significant loss of emergency related information may cause mismanagement of emergency response efforts. We propose a reliable routing scheme for post-disaster ad hoc communication networks, which finds the shortest possible routes with all reliable nodes. The proposed scheme also detects packet forwarding misbehavior caused by network fault or congestion in an active route and reroutes packets through other reliable route. The performance of the proposed scheme is evaluated in terms of packet delivery ratio, end-to-end delay and routing overhead through extensive simulations.

An Efficient Method for Constructing Underwater Sensor Barriers

Abstract: Anti-submarine warfare(ASW) is a critical challenge for maintaining a fleet presence in hostile areas. Technology advancement has allowed submarines to evade standard sonar detection. A viable alternative is to place magnetic or acoustic sensors in close proximity to possible underwater pathways of submarines. This approach may require deploying large-scale underwater sensor networks to form 3-dimensional barriers. We present new results on sensor barriers for 3-dimensional sensor networks. We first show that when sensor locations follow a Poisson Point Process then sensor barriers in a large 3- dimensional fixed emplacement sensor field are unlikely to exist. We use the notion of 3-dimensional stealth distance to measure how far a submarine can travel in a sensor network without being detected. We devise an energy-conserving scheme to construct 3- dimensional barriers using mobile sensors. We focus on develop- ing an energy efficient matching of mobile sensors to cover grid points using distributed auction algorithms. Specifically, we try to minimize the maximum travel distance between any sensor and its assigned grid point. Through simulation we show in comparison to the optimal solution, the distributed auction based approach offers reduced computation time and similar maximum travel distance. This provides a promising new approach to constructing barriers in 3-dimensional sensor networks.

Delay Tolerant Network on Android Phones: Implementation Issues and Performance Measurements

Abstract: Many regions of the world do not have access to the Internet due to lack of proper communication infrastructure. Delay Tolerant Network (DTN) provides communication in a challenging network conditi ...

Mobility-adaptive Routing for Stable Transmission in Mobile Ad Hoc Networks

Abstract: In mobile ad hoc networks (MANETs), node mobility causes network topologies to change dynamically over time, which complicated important tasks such as routing. The previous stability-oriented routing algorithms usually focus on how to discover a stable route, but rarely consider the adaptability of constructed route to the change of node’s motion. In this paper, a mobility-adaptive routing for stable transmission is proposed. In the proposed routing algorithm, no information about neighborhood needed to maintain by nodes, and the link expiration time (LET), which is used to assess the stability of link, is calculated accurately in company with the discovery of some available stable routes in reactive manner. Then the asynchronous mobility information mechanism is introduced to make the stability of current route can adapts to node’s motion. Based on the updated RET, the discovery of alternative stable route is determined by the critical LET zone, which can ensure the continuous transmission of data. Simulation results indicate that the proposed mobility-adaptive routing scheme can improve network performance effectively.

A Scalable DDoS Detection Framework with Victim Pinpoint Capability

Abstract: In recent years, various intrusion detection and prevention systems have been proposed to detect DDoS attacks and mitigate the caused damage. However, many existing IDS systems still keep per-flow state to detect anomaly, and thus do not scale with link speeds in multigigabit networks. In this paper, we present a two-level approach for scalable and accurate DDoS attack detection by exploiting the asymmetry in the attack traffic. In the coarse level, we use a modified count-min sketch (MCS) for fast detection, and in the fine level, we propose a bidirectional count sketch (BCS) to achieve better accuracy. At both detection levels, sketch structures are utilized to ensure the scalability of our scheme. The main advantage of our approach is that it can track the victims of attacks without recording every IP address found in the traffic. Such feature is significant for the detection in the highspeed environment. We also propose a SRAM-based parallel architecture to achieve high-speed process. Furthermore, we analyze accuracy estimation issues to provide hints for practical deployment with constraint memory. We finally demonstrate how to extend our original scheme to a collaborative detection framework. Experimental results using the real Internet traffic show that our approach is able to quickly detect anomaly events and track those victims with a high level of accuracy while it can save over 90% key storage compared with previous sketch-based approaches.

CP-ABE based data access control for cloud storage

Abstract: To solve the safety issues in cloud storage services for network characteristics and data sharing characteristics,and based on the CP-ABE(cipertext policy-attribute based encryption) algorithm,a cipher text access control mechanism was proposed.According to access control and related architecture,the corresponding secure data structure algorithms were given.After this,the simulations and the performance analysis were given to evaluate our algorithm.Under the premise of untrusted service provider,the proposed mechanism can ensure the data security of the cloud storage system in an open environment,and can reduce right management complexity through property management.

Trajectory clustering algorithm based on structural similarity

Abstract: For current trajectory clustering algorithms,most of them group full trajectories as basic units,and lead the low efficient results.Aiming at this problem,a trajectory clustering algorithm based on structural similarity was proposed.By introducing a new concept of trajectory structure and presenting structural similarity function,the internal and external features of trajectories were analyzed.The algorithm first partitioned trajectories into trajectory segments according to corner;then computed the matching degree between every trajectory segment pairs by comparing their structure features;finally grouped trajectories into clusters.Experiment results on real data set demonstrate not only the efficiency and effectiveness of the algorithm,but also the flexibility that feature sensitivity can be adjusted by different parameters.

Performance of Turbo-SISO, Turbo-SIMO, Turbo-MISO and Turbo-MIMO system using STBC

Abstract: In this paper, performance of a Turbo coded wireless link is evaluated in the presence of Rayleigh fading for single-input single-output (SISO), single-input multiple-output(SIMO), multiple-input single-output (MISO) and multiple-input multiple-output (MIMO) system. Turbo encoded and 64-ary Quadrature Amplitude Modulation (QAM) modulated data are further encoded using space-time block coding (STBC) and then split into n streams which are simultaneously transmitted through single transmit antenna for Turbo-SIMO system and n transmit antennas for Turbo-MISO and Turbo-MIMO system. Simulation results obatianed show that the Turbo-SISO system provides 45 dB coding gain, Turbo-SIMO system provides 27,20 and 17 dB coding gain for 2,3 and 4 receive antenna respectively, Turbo-MISO system provides 26, 19 and 15 dB coding gain for 2,3 and 4 transmit antenna respectively, Turbo-MIMO system provides 12 to 17 dB coding gain for different combination of transmit and receive antennas at a BER of 10 -6 compared to uncoded SISO, SIMO, MISO and MIMO system.

achieving efficient dynamic cryptographic access control in cloud storage

Abstract: To keep the data in the cloud confidential against unauthorized parties,a cryptographic access control solution called hybrid cloud re-encryption(HCRE) based on attribute-based encryption(ABE) was introduced.HCRE designed a secret sharing scheme to delegate the task of ABE re-encryption to the cloud service provider(CSP),which alleviates the administering burdens on the data owner.Experiments show that HCRE can handle dynamic access policies in a more ef-ficient way.Additionally,HCRE does not reveal extra information of the plaintext to the CSP,thus it does no harm to the data confidentiality.

Predicting self-similar networking traffic based on EMD and ARMA

Abstract: A novel method based on empirical mode decomposition(EMD) and ARMA was proposed to model and fore-cast self-similar networking trafficThe results demonstrate that EMD had the function of getting rid of the long range dependence(LRD) in traffic dataTherefore,the self-similar traffic processed by EMD could be modeled and predicted well by using ARMA which was a short range dependent(SRD) modelMoreover,the complexity of the proposed method was reduced sharply and the prediction precision was higher than radial basis function neural network

Resilient method for recovering coverage holes of wireless sensor networks by using mobile nodes

Abstract: Coverage holes directly reduce network performance and become a key problem of static wireless sensor net-works.A hole-patching method was presented to get the resilient coverage,in which mobile nodes were guided by the boundary nodes of the coverage hole and patched uncovered area in the hole triangle by triangle.Based on geometry theories and mathematic deduction,the moving destination of the mobile nodes was proved to be optimal,and the cover-age of the patched holes was higher than 90%.Simulation results show the coverage,stability and redundancy of the proposed method,and then the availability was compared with some related methods reported recently.

QoS preference-aware replica selection strategy in cloud computing

Abstract: A QoS preference-aware replica selection strategy for a kind of users with individual QoS sensitivity (IQS) constraints in cloud computing datacenters was put forward in advance. According to the QoS requirements of data ser- vices from IQS users, a novel three-dimensional QoS model of replica selection was introduced, and a QoS prefer- ence-aware algorithm based on analytic hierarchy process (AHP) named QoPA was proposed to deal with the IQS con- straints. In order to evaluate the replica sites in datacenters and provide the best of them to the IQS users, an algorithm for replica selection based on fuzzy comprehensive evaluation termed FCE_RS was designed and implemented. Results of experiments show that the FCE_RS can serve the various IQS users in cloud computing very well by providing reason- able replica strategies effectively.

UWB Communication Characteristics for Different Materials and Shapes of the Stairs

Abstract: A comparison of ultra-wideband (UWB) communication characteristics for two different shapes of stairs with concrete and iron materials are investigated. The impulse responses of these stairs are computed by shooting and bouncing ray/image (SBR/Image) techniques and inverse Fourier transform. Numerical results show that the bit error rate (BER) of binary-pulse amplitude modulation (B-PAM) system for the concrete case is smaller than that for the iron case. Finally, it is worth noting that in these cases the present work provides not only comparative information but also quantitative information on the performance reduction.

Parameter Selection in Public Key Cryptosystem based on Chebyshev Polynomials over Finite Field

Abstract: A recently proposed public key cryptosystem based on Chebyshev polynomials suggests a new approach to data encryption. But the security of the cryptosystem has not been investigated in depth, for lack of an appropriate analysis method. In this paper, a new representation of Chebyshev polynomial is introduced to study security issues of the cryptosystem. The properties of Chebyshev polynomial sequence are presented, and their impact on the cryptosystem are discussed. Finally some principles for parameter selection for the cryptosystem are proposed. The methodology used in this paper is supposed to offer a useful means for future researches on this topic.

Understanding Static Intercell Interference Coordination Mechanisms in LTE

Abstract: This work identifies the factors which determine the behaviour of static interference avoidance schemes: SINR distribution shift, MCS mapping, and proportional MCS usage. The work goes on to challenge the common assumption that it is "best" to give resources with a high reuse factor to those at the cell-edge, by showing for a fixed rate service class, that it is best to be greedy and give these resources to those at the cell-centre. The work is performed using monte-carlo simulations, only in the downlink direction, on a London scenario with realistic path loss and network data. All work is statistically quantified using appropriate tests.

A MACA-based MAC protocol for underwater acoustic sensor networks

Abstract: The medium access control (MAC) protocol design of underwater acoustic sensor networks (UWASNs) faces many challenges: the power limitation at nodes, long propagation delay, low data rates, etc. These challenges of underwater acoustic channels result in the unsuitable usage of terrestrial networks MAC protocol in UWASNs. Moreover, the long propagation delay causes a serious problem for the MAC protocol. In this paper, we propose a new MACA-based MAC protocol with delay tolerant (MACA-DT). It is shown that by using adaptive silent time and simultaneous handshake technique, MACA-DT protocol can improve the channel utilization and alleviate the long end-to-end delay. Simulation results show that our protocol can significantly improves the network throughput and decreases the end-to-end delay when compared with traditional MACA protocols.

Blind estimation of spreading sequence of CDMA signals based on Fast-ICA and performance analysis

Abstract: The DS-CDMA signals can be divided into two types,the short-code(SC) and the long-code(LC) DS-CDMA signal.The existing methods are only used to estimate spreading sequences of SC-DS-CDMA signals,which cannot work for the LC-DS-CDMA signals.A new blind estimation algorithm for DS-CDMA signals based on fast independent com-ponent analysis was proposed by analyzing the mathematical model of the LC-DS-CDMA signal and the estimation per-formance of the proposed algorithm in theory was deduced.Moreover,the proposed method not only applies to the LC-DS-CDMA but also SC-DS-CDMA signals.The theoretical analysis and simulation results verify the effectiveness of the proposed algorithm.

I2V Highway and Urban Vehicular Networks: A Comparative Analysis of the Impact of Mobility on Broadcast Data Dissemination

Abstract: In this paper, we consider the problem of disseminating data in Infrastructure-to-Vehicular (I2V) IEEE 802.11 networks. We analyze, with acomparative approach, the performance in highway and urban scenarios.In particular, after characterizing the mobility in these scenarios we analyze the performance in terms of data dissemination from a fixed Road Side Unit (RSU) to the vehicles passing in its proximity through a recently proposed multihop probabilistic broadcasting protocol, namely Irresponsible Forwarding (IF). In the case of highway-like Vehicular Ad-Hoc NETworks (VANETs), we first characterize a mobile scenario in such a way to make a direct comparison with a static scenario meaningful, taking into account a physical characterization of the network (e.g., in termsof vehicle spatial density). Then, we consider a few mobile urban scenarios, characterized by the presence of junctions regulated byTraffic Lights (TLs) and Roundabouts (Rs). Our results show that, from a single packet perspective, the vehicles' mobility does not affect the behavior of the IF protocol, at least in the considered mobile scenarios (both highway and urban). However, different conclusions are reached when an information flow (i.e., a series of consecutive packets) is considered. In this context, we determine the maximum amount of data which can be transferred from the RSU to the mobile vehicles passing through a certain Region Of Interest (ROI) around the RSU.