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Energy harvesting is a promising technology for extending the lifetime of sensor networks with the restrictions of limited battery energy. One of the main challenging issues is to maximize the sampling rates of all sensor nodes. In this paper, we are concerned with how to adaptively decide the sampling rate for each rechargeable sensor node with a limited battery capacity to maximize overall network utility. To solve the problem, we firstly propose an adaptive energy allocation scheme for each node to manage its energy use in an efficient way. Then we develop a distributed sampling rate control (DSRC) algorithm to obtain the optimal sampling rate. Extensive simulations using real experimental data obtained from Baseline Measurement System (BMS) of Solar Radiation Research Laboratory are performed to demonstrate the efficiency of our algorithm. [ABSTRACT FROM PUBLISHER]

One of the challenging roadblocks stunting the development and commercialization of mobile ad hoc networks (MANETs), is the lack of a thorough understanding of the fundamental performance limits in MANETs. Distinguished from available works which mainly focused on deriving order sense scaling laws of the delay performance in MANETs and usually assumed a localized transmission range, this paper examines the MANET packet delay from a much more detailed perspective. Specifically, we assume for each node a general transmission power control such that the transmission range can be flexibly adapted and adopt a generalized two-hop relay with limited packet redundancy for packet routing. For a tagged traffic flow in the MANET, we first develop a theoretical framework based on two correlated FIFO queues to fully characterize the complicated packet delivery process. Then for any feasible traffic input rate there, we derive closed-form expressions for the corresponding expected end-to-end packet delay. Extensive simulations are further conducted to validate our theoretical results. [ABSTRACT FROM PUBLISHER]

In this paper, a cooperative framework in cognitive radio networks, which addresses energy efficiency of the primary users (PUs) and trustworthiness of secondary users (SUs), is proposed. Specifically, the cooperation involves a PU selecting the most suitable SU as the cooperative relay and allocating the spectrum access intervals for relaying its message and rewarding the SU for its help in relaying the PU's message. Based on the PU's strategy, the selected SU determines its optimal transmission power. The above sequential decision procedure, with the PU as the leader and the SU as the follower, is formulated as a Stackelberg game. The outcomes of the proposed cooperative strategy, including partner selection, cooperation in an untrustworthy environment, and energy efficiency consideration, are analyzed. Numerical results demonstrate that, with the proposed relay selection scheme, the PU can achieve high energy saving through cooperation with the trustworthy SU. [ABSTRACT FROM PUBLISHER]

Cooperative relaying is a promising technique for Long Term Evolution Advanced (LTE-A) networks to satisfy high throughput demand and support heterogeneous communication services with diverse quality-of-service (QoS) requirements. However, efficient relay selection as well as resource allocation are critical in such a network when multiple users and multiple relays are considered. In this paper, a resource allocation problem of maximizing the total achievable throughput for multi-user cooperative LTE-A uplink system considering heterogeneous services is investigated. An optimal joint relay selection, subcarrier assignment and power allocation scheme under total power constraint is proposed. The optimization problem is formulated as a convex optimization problem and solved by decomposing it into a hierarchy of subproblems with reduced computational complexity. The subgradient method is used to find the Lagrange multipliers, which helps to obtain the optimal solution. Numerical results show that our approach supports heterogeneous services while guaranteeing each user's QoS requirements with slight total system throughput degradation. [ABSTRACT FROM PUBLISHER]

In vehicular ad hoc networks (VANETs), improving uploading efficiency is crucial to enabling the copious applications such as reporting sensed data for traffic management or environment monitoring. Depending on the applications, the contents to be uploaded can be of large volumes. Therefore, there exist the fundamental demands of the delivery with high throughput. In this paper, we derive the achievable throughput capacity scaling law for such applications in VANETs as Θ(1/log n), with the number of road-side units scaling as Θ(n/log n). Furthermore, by exploring the mobility diversity among vehicles, we propose a novel two-hop forwarding scheme to improve the throughput performance approaching the throughput capacity. Specifically, the source vehicle distributes the contents to multiple relay vehicles with the largest mobility diversity so that the number of concurrent transmissions can be increased. The simulation results demonstrate the effectiveness of the proposed transmission scheme in terms of the increased throughput performance. [ABSTRACT FROM PUBLISHER]

In this paper, we design a distributed relay selection strategy to achieve equal power consumption for all available relay nodes in AF cooperative system. This strategy gives a closed-form expression for the weight coefficient introduced to achieve the required fairness. It aims to reduce the complexity of the conventional centralized strategy that also tries to divide the total consumed power equally among the relay nodes but requires a knowledge of the average signal-to-noise ratios (SNRs) of the relay path for all relay nodes, a central controller, and a numerical equation-solving method to find the corresponding weight coefficient for each relay node. We show that our distributed strategy can divide the power consumption fairly and approach the equal average power consumption when only the average SNRs of the relay path are known locally. Also we show that our proposed strategy still provides similar outage probability as that provided by the conventional one. [ABSTRACT FROM PUBLISHER]

Cost function based routing has been widely studied in wireless sensor networks for energy efficiency and network lifetime elongation. Existing algorithms however have limited effects because they adopt a single cost function that does not fully capture nodal energy consumption situation. In this paper, we propose a novel Double Cost Function based Routing (DCFR) algorithm, which takes into account end-to-end energy consumption, nodal remaining energy, and energy consumption rate altogether. An extensive simulation indicates that DCFR can lead to more balanced and efficient energy usage among nodes than existing algorithms. [ABSTRACT FROM PUBLISHER]

In this paper, a concurrent transmission scheduling algorithm is proposed to enhance the resource utilization efficiency for multi-Gbps millimeter-wave (mmWave) networks. Specifically, we exploit spatial-time division multiple access (STDMA) to improve the system throughput by allowing both non-interfering and interfering links to transmit concurrently, considering the high propagation loss at mmWave band and the utilization of directional antenna. Concurrent transmission scheduling in mmWave networks is formulated as an optimization model to maximize the number of flows scheduled in the network such that the quality of service (QoS) requirement of each flow is satisfied. We further decompose the optimization problem and propose a flip-based heuristic scheduling algorithm with low computational complexity to solve the problem. Extensive simulations demonstrate that the proposed algorithm can significantly improve the network performance in terms of network throughput and the number of supported flows. [ABSTRACT FROM PUBLISHER]

In this paper, we propose EM3 A, a novel scheme that guarantees the authenticity of a mobile node (MN) and a relay node (RN) in a multi-hop-enabled Proxy Mobile IP (PMIP) network. EM3 A works in conjunction with a proposed scheme for key establishment, based on symmetric polynomials, to generate a shared secret key between MN and RN. This scheme achieves lower revocation overhead than that achieved by existing symmetric polynomial-based schemes. For a PMIP domain with n points of attachment, EM3 A achieves t×2n-secrecy, whereas the existing authentication schemes achieve only t-secrecy. Computation and communication overhead analysis, as well as simulation results, demonstrate that EM3 A achieves low authentication delay and is suitable for seamless multi-hop IP communications. [ABSTRACT FROM PUBLISHER]

Smart community is an emerging Internet of Things application. It supports a variety of high-value automated services such as pervasive healthcare through a multi-hop community network of smart homes in a local residential region. In this paper, we study privacy preserving data communication between patients and an online healthcare provider (referred to as vendor) for efficient remote healthcare monitoring (RHM) in a smart community environment. We adopt patients' attribute structures instead of their identities for authentication and preserve identity privacy during patient-to-vendor communication, and we build a receiver chain among smart homes to enable vendor-to-patient communication and achieve location privacy. The privacy preserving properties of the proposed data communication scheme are analyzed, and its effectiveness and efficiency are demonstrated through extensive simulations. [ABSTRACT FROM PUBLISHER]

In habitat monitoring applications, when a sensor node detects an endangered animal, e.g., a panda, it reports the animal's presence and activities to the sink. However, the adversaries can eavesdrop on the network transmissions and make use of the traffic information to locate pandas to hunt them. In this paper, we first define hotspot phenomenon that causes an obvious inconsistency in the network traffic pattern due to the large volume of packets originated from a small spot. Second, we develop a realistic adversary model assuming that the adversary can monitor the network traffic in multiple areas rather than the entire network or only one area. We then introduce a novel attack called Hotspot-Locating where the adversary uses traffic analysis techniques to locate hotspots. Simulation and analytical results demonstrate that Hotspot-Locating attack is a severe threat to the source nodes' location privacy and the existing routing-based privacy preserving schemes are vulnerable to this attack because they leak traffic analysis information that can be used to locate the source nodes. For stronger privacy preservation, the traffic analysis information such as packet correlation and the nodes' packet sending rates should be concealed. [ABSTRACT FROM PUBLISHER]

In this paper, we propose a novel scheme for efficiently and securely preserving source nodes' location privacy. Our scheme uses efficient cryptographic operations to change the packets' appearance at each hop to prevent packet correlation. It also creates a cloud with irregular shape of fake traffic to enable the real source node to send its data anonymously to a fake source node to send to the sink and to camouflage the real source node in the nodes creating the cloud. To reduce the energy cost, clouds are active only during data transmission and the intersection of clouds creates a larger merged cloud to reduce the number of fake packets and boost privacy preservation. Simulation and analytical results demonstrate that our scheme can provide stronger privacy preservation than routing-based schemes and requires much less energy cost than global-adversary-based schemes. [ABSTRACT FROM PUBLISHER]

Cloud storage is one of the underlying services in cloud computing. However, there are some critical issues in file storage which should be resolved urgently, such as the blocking file storage. In order to solve the shortages of hot file storage and parallel computing support issues in fixed-blocking storage, we propose a smart-blocking file storage method in this paper. By setting up 6 grouping factors, the method can determine whether the file should be blocked or not automatically depending on the size of the file and the client bandwidth. The proposed method can block the file into similar size sub-blocks as large as possible when the file is judged to be blocked. Normally the size of the last sub-block is smaller than other similar sub-blocks. But the gap maintains within the size of the next smaller grouping factor. The Metadata server can address the hot files when the file is blocked. In addition, the proposed method also defines the file uniformity and the system uniformity to quantitatively describe the uniformity of sub-blocks in the file and in the whole system. Analysis and simulation demonstrate the proposed method has better system uniformity in file storage, the node load balance caused by hot file, and a large number of file fragments reduction. [ABSTRACT FROM PUBLISHER]

Due to the openness of the wireless media and frequent interactions among sensor nodes, security has been tightly related to the data credibility and network reliability in wireless sensor networks (WSNs). In this paper, based on fuzzy theory and evidence theory, we present a novel trust model to detect anomaly nodes in WSNs. Specifically, by observing nodes' behaviors with multi-dimensional characteristics, the proposed model can be used to efficiently identify malicious nodes while validating the normal operations. Extensive simulations are conducted, and the simulation results demonstrate the proposed trust model can achieve higher detection rate of malicious nodes in comparison with previously reported ones. [ABSTRACT FROM PUBLISHER]

With powerful computing capability, plentiful functionality and advanced operating systems with flexible APIs, smartphones have become indispensable part of our daily lives. However, growing functionality, complexity and popularity of smartphones have also increased concerns about information security, and these concerns have been further exacerbated by rich third-party applications. In order to protect information security, significant research and standardizations efforts have been made in recent years. However, most of these activities focus on specific issues, which cannot mitigate negative effects as a whole. In this paper, we first introduce a common architecture of smartphones including main smartphone assets. Then we identify smartphone threats which are clustered into vulnerabilities and attacks. Based on the layered structure of smartphones, we propose a hierarchical security framework for smartphones including hardware security, operating system security, application security, user data security and communication security. Finally, we present the preliminary security solutions with regard to the security framework, and give future research direction. [ABSTRACT FROM PUBLISHER]

The electrical grid is a critical infrastructure that is slowly moving towards a more reliable and efficient supply system: the Smart Grid. As part of this migration process, a new group of energy-aware and emission-free technologies are being developed. Electric vehicles are a promising technology that belongs to that group. By connecting the electric vehicles to the grid, an energy-efficient cycle is created, in which the vehicles not only draw power from the grid, but they also send electricity back into it. For a successful vehicle to grid (V2G) interaction, a reliable and ubiquitous V2G communications network should be deployed. While previous research has focused on V2G data transmission when the vehicle is connected to the grid, we focus on the advantages of enabling the exchange of data while on-the-go by means of a wirelessly connected smart metering infrastructure network. Furthermore, this paper proposes a complete framework for the support of IP communications in mobile V2G environments. We perform simulations based on realistic channel models for smart metering networks to evaluate the performance of the proposed framework, and demonstrate the feasibility of IP communications as a promising platform for the deployment of innovative V2G applications. [ABSTRACT FROM PUBLISHER]