Showing papers in "Telecommunication Systems in 2015"
TL;DR: This paper provides case studies in which new data structures and related algorithms are successfully implemented using RViz, including geometry synthesis, distance field representation, and implicit surface reconstruction.
Abstract: In computational science and computer graphics, there is a strong requirement to represent and visualize information in the real domain, and many visualization data structures and algorithms have been proposed to achieve this aim. Unfortunately, the dataflow model that is often selected to address this issue in visualization systems is not flexible enough to visualize newly invented data structures and algorithms because this scheme can accept only specific data structures. To address this problem, we propose a new visualization tool, RViz, which is independent of the input information data structures. Since there is no requirement for additional efforts to manage the flow networks and the interface to abstracted information is simple in RViz, any scientific information visualization algorithms are easier to implement than the dataflow model. In this paper, we provide case studies in which we have successfully implemented new data structures and related algorithms using RViz, including geometry synthesis, distance field representation, and implicit surface reconstruction. Through these cases, we show how RViz helps users visualize and understand any hidden insights in input information.
116 citations
TL;DR: An overview of state-of-the-art research that addresses the high energy consumption in cognitive radio networks (CRNs) is provided and important design guidelines of an energy-efficient framework for cooperative spectrum sensing are suggested.
Abstract: Cognitive radio has been proposed as a promising technology to resolve the spectrum scarcity problem by dynamically exploiting underutilized spectrum bands. Cognitive radio technology allows unlicensed users to exploit the spectrum vacancies at any time with no or limited extra interference at the licensed users. Usually, cognitive radios create networks in order to better identify spectrum vacancies, avoid resultant interference, and consequently, magnify their revenues. One of the main challenges in cognitive radio networks (CRNs) is the high energy consumption, which may limit their implementation especially in battery-powered terminals. The large consumption mainly occurs during the spectrum sensing stage, especially if a cooperative approach is employed, and has an impact on the data transmission stage. Many algorithms have been proposed in the literature in order to improve the energy efficiency of cooperative spectrum sensing methods in CRNs. In this article, we provide an overview of state-of-the-art research that addresses this problem. Furthermore, we suggest important design guidelines of an energy-efficient framework for cooperative spectrum sensing.
70 citations
TL;DR: This paper compares the normalised Laplacian spectra of physical- and logical-level topologies of four commercial ISPs and two research networks against the US freeway topology, and shows analytically that physical level communication networks are structurally similar to the USeway topology.
Abstract: For many years the research community has attempted to model the Internet in order to better understand its behaviour and improve its performance. Since much of the structural complexity of the Internet is due to its multilevel operation, the Internet's multilevel nature is an important and non-trivial feature that researchers must consider when developing appropriate models. In this paper, we compare the normalised Laplacian spectra of physical- and logical-level topologies of four commercial ISPs and two research networks against the US freeway topology, and show analytically that physical level communication networks are structurally similar to the US freeway topology. We also generate synthetic Gabriel graphs of physical topologies and show that while these synthetic topologies capture the grid-like structure of actual topologies, they are more expensive than the actual physical level topologies based on a network cost model. Moreover, we introduce a distinction between geographic graphs that include degree-2 nodes needed to capture the geographic paths along which physical links follow, and structural graphs that eliminate these degree-2 nodes and capture only the interconnection properties of the physical graph and its multilevel relationship to logical graph overlays. Furthermore, we develop a multilevel graph evaluation framework and analyse the resilience of single and multilevel graphs using the flow robustness metric. We then confirm that dynamic routing performed over the lower levels helps to improve the performance of a higher level service, and that adaptive challenges more severely impact the performance of the higher levels than non-adaptive challenges.
66 citations
TL;DR: The proposed protocol combines two different medium access methods, namely polling and probabilistic contention access, to adapt its operation to the different energy and state changes that the network nodes may experience due to their random nature and the time variation of the energy harvesting sources.
Abstract: This paper introduces human energy harvesting medium access control (MAC) protocol (HEH-BMAC), a hybrid polling MAC suitable for wireless body area networks powered by human energy harvesting. The proposed protocol combines two different medium access methods, namely polling (ID-polling) and probabilistic contention access, to adapt its operation to the different energy and state (active/inactive) changes that the network nodes may experience due to their random nature and the time variation of the energy harvesting sources. HEH-BMAC exploits the packet inter-arrival time and the energy harvesting rate information of each node to implement an efficient access scheme with different priority levels. In addition, our protocol can be applied dynamically in realistic networks, since it is adaptive to the topology changes, allowing the insertion/removal of wireless sensor nodes. Extensive simulations have been conducted in order to evaluate the protocol performance and study the throughput and energy tradeoffs.
53 citations
TL;DR: An energy-efficient delay-aware cooperative scheme, exploited for efficient resource management and maximum energy conservation in a 5G mobile cognitive radio network architecture, based on the comparison of the queuing delays of both the secondary nodes and the Radio Access Points.
Abstract: This paper proposes an energy-efficient delay-aware cooperative scheme, exploited for efficient resource management and maximum energy conservation in a 5G mobile cognitive radio network architecture. The proposed scheme is based on the comparison of the queuing delays of both the secondary nodes and the Radio Access Points, when delay sensitive transmission is requested, providing optimal TV White Spaces exploitation via a spectrum broker. The spectrum broker manages the process of the energy consumption of the 5G mobile communication systems, according to the proposed delay-aware cooperative scheme and the comparative evaluation of the queuing delays. The validity of the performance of the scheme is verified through extended simulation tests, carried out under controlled experimental conditions.
43 citations
TL;DR: A new lifetime extended multi-levels heterogeneous routing (LE-MHR) protocol for WSNs, which includes horizontal and vertical levels of node heterogeneity and gives a guarantee for an enhancement of initial energy of network field for higher level, and number of advanced nodes is independent to any level of hierarchy in the network.
Abstract: IoT, Smart Grid and M2M are paradigms that are expected to dominate in 5G networks and, hence, the role of WSNs is of great importance. In WSNs, horizontal and vertical levels of node heterogeneity has been studied in the past for various operation such as data capturing, processing and communication at different levels of nodes in wireless sensor networks (WSNs). For saving energy consumption of nodes in these networks, many existing proposals in literature have considered 1st to $$k$$kth level energy heterogeneity of sensor nodes. But major problem in the existing solutions is that an enhancement of initial energy of network may not guarantee an enhancement of initial energy for higher level nodes in comparison to the lower level nodes. In addition to this, number of nodes in higher level is always less than the number of nodes in lower level. To address these issues, in this paper, we proposed a new lifetime extended multi-levels heterogeneous routing (LE-MHR) protocol for WSNs, which includes $$k$$k levels horizontal energy heterogeneity. LE-MHR gives a guarantee for an enhancement of initial energy of network field for higher level, and number of advanced nodes is independent to any level of hierarchy in the network. Performance of the proposed scheme was evaluated by performing extensive simulations with respect to various performance evaluation parameters and results obtained were compared with other pre-existing prominent protocols. Results obtained shows that, by varying the initial energy, and energy heterogeneity parameters, the network lifetime of LE-MHR was improved 53.7, 46.9 and 44.1 % with respect to SEP, MCR and EEMHR protocols respectively.
39 citations
TL;DR: Radio frequency identification (RFID) is a kind of electronic identification technology that is becoming widely deployed and has tremendous potential to improve patient healthcare quality by eliminating human errors and ambiguity presented during patient-physicians and physician-physician interactions.
Abstract: Information processing is the cornerstone of patient safety and healthcare quality. In the current healthcare system, critical gaps exist in the collection of vital information from patients and transferring that information to healthcare providers. The information collection problems are particularly challenged in patients lacking verbal communication or under other serious conditions. Information handover among medical staff can also introduce human errors which may place a patient's health and life at risk. Radio frequency identification (RFID) is a kind of electronic identification technology that is becoming widely deployed. RFID technology allows crucial personal information to be saved in a low-cost chip attached to the patient. This innovative technology has tremendous potential to improve patient healthcare quality by eliminating human errors and ambiguity presented during patient-physician and physician-physician interactions.
36 citations
TL;DR: Future research trends in software failure mitigation, reliability of wireless communications, robust optimization and network design, multilevel and multirealm network resilience, multiple criteria routing approaches in multilayer networks, resilience options of the fixed IP backbone network in the interplay with the optical layer survivability and reliability of cloud computing networks are outlined.
Abstract: In this position paper on reliable networks, we discuss new trends in the design of reliable communication systems. We focus on a wide range of research directions including protection against software failures as well as failures of communication systems equipment. In particular, we outline future research trends in software failure mitigation, reliability of wireless communications, robust optimization and network design, multilevel and multirealm network resilience, multiple criteria routing approaches in multilayer networks, resilience options of the fixed IP backbone network in the interplay with the optical layer survivability, reliability of cloud computing networks, and resiliency of software-defined networks. Described research directions are frequently enhanced with examples.
34 citations
TL;DR: An energy efficiency optimization model for the IEEE 802.15.6 standard based wireless body area network by focusing on physical (PHY) and medium access control (MAC) layers taking into account relevant characteristics therein is described.
Abstract: An energy efficiency optimization model for the IEEE 802.15.6 standard based wireless body area network is described in this paper. Cross-layer approach has been used here by focusing on physical (PHY) and medium access control (MAC) layers taking into account relevant characteristics therein. Studied PHY is based on impulse radio ultra wideband (IR-UWB) signaling with mandatory on---off keying modulation and non-coherent energy detection receiver. The analyzed MAC protocol is slotted Aloha which is used in the contention based mode of the IEEE 802.15.6 std. using IR-UWB PHY. The proposed model can be used to compare the energy efficiency of uncoded and coded transmissions using different Bose---Chaudhuri---Hocquenghem code rates. The model enables joint code rate and packet length optimization in AWGN channel when using the path loss model for hospital scenario, defined by the IEEE P802.15 working group. Results clearly show the most energy efficient code rate and packet length as a function of distance.
32 citations
TL;DR: An underwater wireless group-based sensor network is proposed in order to quantify and monitor the accurate amount of pollution that is deposited on the seabed and determine the amount of food that is wasted while it measures theamount of deposits generated.
Abstract: One of the main problems in marine fish farms sustainability is the amount of uneaten feed and fecal waste dispersed and deposited on the seabed under the cages. It damages the fauna and flora, and decreases the economic benefits because the wastage of the uneaten food. Several country governments and international associations have published laws and rules about the maximum permitted pollution on the seabed in order to avoid having high impact on the environment. In this paper, we propose an underwater wireless group-based sensor network in order to quantify and monitor the accurate amount of pollution that is deposited on the seabed. First, we present an analytical model and study the best location to place the sensor nodes. The mobility of the nodes and the group-based protocol operation is described. Our wireless group-based sensor network proposal is able to determine the amount of food that is wasted while it measures the amount of deposits generated. This data can be used to compute and estimate more accurately the amount of food that should be thrown into the cage. Finally, several simulations are presented in order to show the network traffic and to verify the correct operation of the wireless sensor system.
29 citations
TL;DR: A novel genetic-concept-based algorithm is proposed for fragile audio watermarking to reduce the distortion of least significant bits substitution and consequently improve the peak signal-to-noise ratio (PSNR) and increase the payload of results.
Abstract: A novel genetic-concept-based algorithm is proposed for fragile audio watermarking to reduce the distortion of least significant bits substitution and consequently improve the peak signal-to-noise ratio (PSNR) and increase the payload of results. The result of testing shows that in comparison with ordinary substitution techniques and other presented techniques, the payload is considerably increased and PSNR (as an indicator of imperceptibility) is noticeably raised.
TL;DR: It is indicated that the nID physical object modeling and addressing provide complements to the ID physical objects for ubiquitous interactions in the IoT.
Abstract: The Internet of Things (IoT) is an emerging network paradigm, and realizes the interconnection among ubiquitous things, along with its corresponding applications and services in both Physical-world and Cyber-world. Some researches have been worked on IoT modeling and addressing, which are mainly based on objects with a unique identifier (ID). However, in practical scenarios, there are several objects without any available ID, namely non-ID (i.e., nID) physical objects, including the objects unattached any ID itself, and the objects attached unreadable or un-trusted ID. It turns out that the nID physical objects related issues become noteworthy. In this paper, we focus on the nID physical objects to present a modeling and addressing solution. Concretely, (1) nID physical objects are described along with the discussion of applying nID solution; (2) a tree-like code structure (i.e., Tree-Code) is introduced to establish a unified modeling scheme for the nID physical objects according to abstracted data elements, and also achieves the compatibility with the ID physical objects considering the ID based data elements; (3) Tree-Code based addressing scheme is presented with dynamic updating considerations. It indicates that the nID physical object modeling and addressing provide complements to the ID physical objects for ubiquitous interactions in the IoT.
TL;DR: The proposed scheme first adopts subjective tests to find the relationships between the QoE and individual QoS parameters, and based on subjective test results, the corresponding QoS–QoE mapping functions forindividual QoS metrics are derived using the regression approach.
Abstract: Traditionally, subjective tests are conducted to obtain the Mean Opinion Score (MOS) or Quality of Experience (QoE) of a video streaming service. However, subjective tests are time-consuming and rather costly. Thus, a cost-effective and real-time QoE evaluation method for video streaming services is presented in this paper. The proposed scheme first adopts subjective tests to find the relationships between the QoE and individual QoS parameters. Next, based on subjective test results, the corresponding QoS---QoE mapping functions for individual QoS metrics are derived using the regression approach. Finally, the integrated QoE function, which is a multi-variate function of multiple QoS metrics, for assessing the overall QoE of video streaming services is proposed. Hence, network/service providers only need to measure related objective QoS parameters while the corresponding MOS/QoE can be easily derived in real time based on the integrated QoE function. Since subjective tests only need to be conducted occasionally for updating the parameters in the QoS---QoE mapping functions, the cost of QoE assessment decreases significantly.
TL;DR: Numerical evaluation of the proposed policies in terms of the average secrecy rate, average delay and power reduction show improved performance compared to other state-of-the-art solutions.
Abstract: In this article, we present relay selection policies in applications with secrecy requirements which are of interest in the fifth generation (5G) of wireless networks. More specifically, we provide a classification of relays based on their distinct communication attributes, such as processing, multiple antennas, storage, channel estimation, density and security level. In addition, we discuss the level of efficiency exhibited by each relay class, regarding their impact in delay-critical applications and green communications applications, while aiming at a specific security level at the physical layer. Then, relay selection policies are proposed taking into consideration the goals set by each application. Numerical evaluation of the proposed policies in terms of the average secrecy rate, average delay and power reduction show improved performance compared to other state-of-the-art solutions.
TL;DR: This work proposes a novel adaptive MAC protocol for WBANs named Network Longevity Enhancement by Energy Aware medium access control Protocol (NLEEAP), which reduces energy consumption without introducing additional devices.
Abstract: Wireless body area networks (WBANs) represent a key emerging technology to resolve the connection issues on, in or around the human body. One of the most important and challenging issues in WBANs is to maximize the network lifetime. Employing additional relaying node to save energy was considered in the literatures available. Different from the related work, we propose a novel adaptive MAC protocol for WBANs named Network Longevity Enhancement by Energy Aware medium access control Protocol (NLEEAP), which reduces energy consumption without introducing additional devices. The procedures in NLEEAP consist of relay request, relay response and superframe adjustment. The relay operation is initiated when the shortage of a node's residual energy occurs. Once the relay succeeds, NLEEAP smoothly switches the network topology from single-hop to multi-hop. Simulations are conducted and the results show the superiority of NLEEAP in energy efficiency compared with that of existing standard of IEEE 802.15.4.
TL;DR: The aim of this study was to identify the major types of energy exhausting attacks in MAC protocols in WBANs, and show how easily the attacks can cause energy exhaustion in different MAC protocols.
Abstract: Because the sensors of wireless body area networks (WBANs) have limited battery power, many studies have focused on energy efficient medium access control (MAC) protocols to extend the lifetime of the sensors. In addition, WBANs face energy-exhausting attacks, which force the sensors to consume battery power partially or thoroughly. These attacks occur mainly in the MAC layer and threaten severely the energy efficiency of MAC protocols in WBANs. Because the attacks are made abruptly and unexpectedly, the lives of human beings and the quality of health care services can be threatened. Therefore, the aim of this study was to identify the major types of energy exhausting attacks in MAC protocols in WBANs, and show how easily the attacks can cause energy exhaustion in different MAC protocols. This survey provides clues for future research into energy efficient MAC protocols in WBANs.
TL;DR: This work performs an analysis of the behavior of the monitoring system, investigating the features that influence the underwater sensor network, using the Opportunistic Network Environment simulator.
Abstract: This paper proposes an underwater monitoring system built with sensors distributed over a subsea infrastructure, which is responsible for operation and transportation of oil production. We consider the use of currently available equipment. Data is transmitted by underwater acoustic modems installed on the sensors, platforms and vessels used for logistic support of the oil exploration. These vessels are used to collect data and provide references for positioning the sensors. However, the vessels may not be within the sensor range at all times, requiring the use of Delay/Disruption Tolerant Network. This work performs an analysis of the behavior of the monitoring system, investigating the features that influence the underwater sensor network, using the Opportunistic Network Environment simulator. In this case, the displacement of logistic-support vessels on the maritime routes is very important, therefore we consider real-world scenarios based on the Brazilian offshore oil exploration area.
TL;DR: An adaptive MAC protocol based on IEEE 802.15.4, namely Ada-MAC, which can not only enable dynamic Guaranteed Time Slots allocation but also provide differentiated services for different nodes according to their data types is proposed.
Abstract: With the increasing demands for high-quality health-care services, medical cyber-physical systems over wireless body sensor networks have emerged as a promising solution for vital life signals monitoring. These systems require the communication protocols to be both reliable and real-time in data transmissions. IEEE 802.15.4 can be regarded as the canonical protocols in this area owing to its low-power and low-cost features. However, it falls short of reliability and timeliness guarantees. To address this issue, we propose an adaptive MAC protocol based on IEEE 802.15.4, namely Ada-MAC. The proposed protocol combines schedule-based on time-triggered protocol and contention-based CSMA/CA mechanism. It can not only enable dynamic Guaranteed Time Slots allocation but also provide differentiated services for different nodes according to their data types. The proposed protocol is implemented on the OMNeT++ platform. Extensive simulations are conducted to evaluate the performance of Ada-MAC in comparison with the traditional IEEE 802.15.4 MAC. The results show the superiority of the proposed protocol in terms of reliability and timeliness.
TL;DR: The proposed communication pattern of vehicular networks, the security solution in detail, a formal security analysis and the experimental implementation of the solution are outlined, and the scheme is evaluated and compared with related schemes.
Abstract: In this paper, we deal with efficient group signatures employed in secure and privacy-preserving vehicular networks. Our solution aims to minimize the impact of several common attacks like denial of services or replay attacks on the efficiency of privacy-preserving security solutions in vehicular networks. Due to advanced properties like a short-term linkability and a categorized batch verification, our solution based on group signatures ensures privacy, security and the efficiency of vehicular networks which can be attacked by malicious parties. We outline the proposed communication pattern of vehicular networks, our security solution in detail, a formal security analysis and the experimental implementation of our solution. In addition, we evaluate and compare our solution with related works. Our group signature scheme is more efficient and secure in the signing phase and in the verification phase than related schemes.
TL;DR: The 2D-DOA estimation algorithm for uncorrelated and coherent signals is proposed and the Cramer–Rao lower bound is derived at last.
Abstract: The multiple input and multiple output (MIMO) and smart antenna (SA) technique have been widely accepted as promising schemes to improve the spectrum efficiency and coverage of mobile communication systems. The definition of direction-of-arrival (DOA) estimation is that multiple directions of incident signals can be estimated simultaneously by some algorithms using the received data. The conventional DOA estimation of user equipments (UEs) is one by one, which is named as sequential scheme. The Virtual MIMO (VMIMO) scheme is that the base station (BS) estimates the DOAs of UEs in a parallel way, which adopts the SA simultaneously. Obviously, when the power is fixed, the VMIMO scheme is much more energy efficient than the sequential scheme. In VMIMO scheme, a set of UEs are grouped together to simultaneously communicate with the BS on a given resource block. Then the BS using multiple antennas can estimate the 2D-DOA of the UEs in the group simultaneously. Based on VMIMO system, the 2D-DOA estimation algorithm for uncorrelated and coherent signals is proposed in this paper. The special structure of mutual coupling matrix (MCM) of uniform linear array (ULA) is applied to eliminate the effect of mutual coupling. The 2D-DOA of uncorrelated signals can be estimated by DOA-matrix method. The parameter pairing between azimuth and elevation is accomplished. Then these estimations are utilized to get the mutual coupling coefficients. Based on spatial smoothing and DOA matrix method, the 2D-DOA of coherent signals can be estimated. The Cramer---Rao lower bound is derived at last. Simulation results demonstrate the effectiveness and performance of the proposed algorithm.
TL;DR: Trade-offs between user throughput and energy efficiency are evaluated, and using the considered mechanism, ES gains of up to 20 % is observed, without significant loss in throughput.
Abstract: In this paper, we consider backhaul-aware mechanisms for energy efficient operation of next generation heterogeneous wireless networks, with dense small cell deployments. We assume control and data plane separation based on the LTE-Advanced dual connectivity architecture. The mechanisms are evaluated using LTE-Advanced heterogeneous network scenarios, with varying levels of network densities, user traffic and cell load conditions. For comparison, conventional traffic offloading schemes based on small cell proximity and load are also evaluated. The performance results indicate significant energy saving (ES) gains for the backhaul-aware mechanism, depending on the backhaul technology used. Evaluations were also done on the impacts of user mobility, and for indoor and outdoor deployments of small cells. Trade-offs between user throughput and energy efficiency are evaluated, and using the considered mechanism, ES gains of up to 20 % is observed, without significant loss in throughput.
TL;DR: This paper proposes to defeat the jamming attacks to the cognitive radio network by introducing the combined online optimization and linear programming to the smart grid to enable the system to heal automatically from theJamming attack.
Abstract: Smart Grid is a promising technology to efficiently manage the power use, transmission and production. An efficient and dependable smart power grid relies on the secure and reliable real-time data collection and transmission service provided by an underlying backbone communication network. Cognitive radio network is an emerging wireless communication technology that fits communication needs in smart grid. However, the cognitive radio is vulnerable to jamming attacks that can disturb the real time communication. The loss of the timely information from the remotely distributedly deployed sensors can cause the loss of control of the system. In this paper, we focus on the availability of the communication services provided by the cognitive radio nodes deployed over the smart grid. We consider the jamming attacks to this wireless network. We propose to defeat the jamming attacks by introducing the combined online optimization and linear programming to the smart grid to enable the system to heal automatically from the jamming attack.
TL;DR: In this article, the analysis, design, and development of the RFID and EPCglobal Network Standards based traceability system that adheres to the requirements of global food traceability in terms of completeness of traceability information was proposed.
Abstract: Traceability system in the food supply chain is becoming more necessary. RFID and EPCglobal Network Standards are emerging technologies that bring new opportunities to develop the high performance traceability system. This research proposes the analysis, design, and development of the RFID and EPCglobal Network Standards based traceability system that adheres to the requirements of global food traceability in terms of completeness of traceability information. The additional components, including lot management system and electronic transaction management system, encourage the traditional system in order to fulfill the missing information. The proposed system was developed and applied in a rice supply chain. Results from experimentation showed that the additional components can significantly improve the completeness of traceability information. The collaboration between EPCglobal Network Standards and electronic transaction management system can improve the performances in RFID operations.
TL;DR: This work has shown that Survivability is capable of capturing complex system recovery behaviors and tracking a large variety of system performance measures, and it also permits relatively simple quantification procedure as described in this paper.
Abstract: Survivability is a concept that describes the capability of a system to achieve timely recovery after the occurrence of undesired events. It is more general and detailed than many terms, such as RTO and RPO, that have a similar goal. Survivability is capable of capturing complex system recovery behaviors and tracking a large variety of system performance measures, and it also permits relatively simple quantification procedure as described in this paper.
TL;DR: Preliminary numerical evaluations conducted on real IP network topologies suggest that rLFA significantly improves the level of protection, and most networks need only 2–3 new links to be added to attain 100 % failure case coverage irrespectively of whether link or node protection is considered.
Abstract: Up to not so long ago, loop-free alternates (LFA) was the only viable option for providing fast protection in pure IP and MultiProtocol Label Switching---Label Distribution Protocol networks. Unfortunately, LFA cannot provide protection for all possible failure cases in general. Recently, the Internet Engineering Task Force has initiated the remote loop-free alternates (rLFA) technique as a simple extension to LFA, to boost the fraction of failure cases covered by fast protection. Before further standardization and deployment, however, it is crucial to determine to what extent rLFA can improve the level of protection against single link or node failures in a general IP network, as well as to find optimization methods to tweak a network for 100 % rLFA coverage. In this paper, we take the first steps towards this goal by solving these problems in the special, but practically relevant, case when each network link is of unit cost. We also provide preliminary numerical evaluations conducted on real IP network topologies, which suggest that rLFA significantly improves the level of protection, and most networks need only 2---3 new links to be added to attain 100 % failure case coverage irrespectively of whether link or node protection is considered.
TL;DR: This paper proposes new energy management scheme using a dynamic power threshold and new sink mobility scheme to balance the network load between sensor nodes and thus improve the performances and shows that the proposal protocol permits to reduce the energy consumption and prolong the network life.
Abstract: Data dissemination in wireless sensor networks is the main goal and the final waited objective of the sensor network deployment. In such environment which consists of a large number of low cost devices, sensor nodes generate sensed data of stimulus and forward them to sinks via wireless multi-hops communication. In typical wireless sensor network, the sensor nodes are equipped with irreplaceable batteries and characterized by limited computing capability. Therefore, minimizing the energy consumption of the sensor nodes and thus maximizing the lifetime of sensor networks is one of the most important research issues. In this paper, we present new data dissemination protocol based energy-efficient called energy-based data dissemination protocol. In this protocol, we propose new energy management scheme using a dynamic power threshold and we introduce also new sink mobility scheme to balance the network load between sensor nodes and thus improve the performances. Firstly, in the initialization phase, the sensor nodes organized under clusters and cluster head should be selected for each cluster. Secondly, in the data dissemination phase, the cluster head collects and transmits the sensed data based on the data dissemination process. In this phase, sensor sink may move toward any cluster based on its sensed data frequency to minimize energy consumption of sensor nodes near the fixed sinks due to relaying of large amount of data. The simulation result shows that the proposal protocol permits to reduce the energy consumption and prolong the network life.
TL;DR: Simulation results show that DT-MAC performs better in providing QoS guarantees and accommodating the change of network scale compared with conventional TDMA-based MAC protocols.
Abstract: This paper presents DT-MAC, a dynamic TDMA based medium access control (MAC) protocol designed to offer collision-free transmissions while providing QoS guarantees for different services in scalable fully connected ad hoc networks. In DT-MAC, a new time frame structure which consists of synchronization, request, assignment and data slots is put forward. In each frame, the number of slots and their lengths are adaptively adjusted according to the number of nodes and their services in the network. Meanwhile, a distributed frame synchronization method is proposed to provide synchronization guarantee for the nodes and generate a manager node for each frame to dynamically allocate the slots according to the QoS requirements of different services. Besides, by introducing request slot, DT-MAC can make nodes join or leave the network without conflicts. Simulation results show that DT-MAC performs better in providing QoS guarantees and accommodating the change of network scale compared with conventional TDMA-based MAC protocols.
TL;DR: This paper presents an adaptive joint routing and bandwidth allocation protocol for traffic streaming in BAN, formulated as Mixed Integer Linear Program that maximizes the network utility while satisfying the QoS requirements.
Abstract: In this paper, we study the problem of routing, bandwidth and flow assignment in wireless body area networks (BANs). We present an adaptive joint routing and bandwidth allocation protocol for traffic streaming in BAN. Our solution considers BAN for real-time data streaming applications, where the real-time nature of data streams is of critical importance for providing a useful and efficient sensorial feedback for the user while system lifetime should be maximized. Thus, bandwidth and energy efficiency of the communication between energy constrained sensor nodes must be carefully optimized. The proposed solution takes into account nodes' residual energy during the establishment of the routing paths and adaptively allocates bandwidth to the nodes in the network. We also formulate the joint routing tree construction and bandwidth allocation problem as Mixed Integer Linear Program that maximizes the network utility while satisfying the QoS requirements. We compare the resulting performance of our protocol with the optimal solution, and show that it closes a considerable portion of the gap from the theoretical optimal solution.
TL;DR: This paper exploits the threshold crypto sharing with group signature mechanism to secure transmitted data with lower cost comparing to other existing ones and very promising its application in cloud environments.
Abstract: Nowadays, cloud computing becomes a popular technology which combines resources of numerous physical computers and servers to perform distributed computing. The main benefit of cloud computing is that this technology decreases computing costs and infrastructures, allowing much more efficient computing. Through a portal, users submit working tasks and receive the results without assigning to specific servers. Nevertheless, the computers of users and enterprises are located in cloud, and arbitrary clients can randomly log on and take private data away. Thus, the cloud security becomes a significant subject. In this paper, we exploit the threshold crypto sharing (Desmedt and Frankel in Advances in cryptology--CRYPTO'89, 1990) with group signature mechanism to secure transmitted data. During map and reduce phases, this mechanism can protect the divided and merged messages from being tampered with. Additionally, this study exploits a virtual machine platform to simulate cloud computing environments and then perform security operations. Experimental results show that the mechanism presented has lower cost comparing to other existing ones and very promising its application in cloud environments.
TL;DR: A new improved Nyquist filter is proposed and investigated and its impulse response is obtained from a linear combination of new Nyquist pulses with different asymptotical decay rates.
Abstract: This paper deals with the design of inter-smybol interference free pulses having reduced sensitivity to time synchronization errors. A new improved Nyquist filter is proposed and investigated. Its impulse response is obtained from a linear combination of new Nyquist pulses with different asymptotical decay rates. Error probability results show that the proposed filter outperforms other existing filters. The proposed scenarios aimed at demonstrating the feasibility of the concept.