Showing papers in "IEEE Wireless Communications in 2013"
TL;DR: It becomes critically important to study how the current approaches to standardization in this area can be improved, and better understand the opportunities for the research community to contribute to the IoT field.
Abstract: Technologies to support the Internet of Things are becoming more important as the need to better understand our environments and make them smart increases. As a result it is predicted that intelligent devices and networks, such as WSNs, will not be isolated, but connected and integrated, composing computer networks. So far, the IP-based Internet is the largest network in the world; therefore, there are great strides to connect WSNs with the Internet. To this end, the IETF has developed a suite of protocols and open standards for accessing applications and services for wireless resource constrained networks. However, many open challenges remain, mostly due to the complex deployment characteristics of such systems and the stringent requirements imposed by various services wishing to make use of such complex systems. Thus, it becomes critically important to study how the current approaches to standardization in this area can be improved, and at the same time better understand the opportunities for the research community to contribute to the IoT field. To this end, this article presents an overview of current standards and research activities in both industry and academia.
744 citations
TL;DR: In this article, various wideband spectrum sensing algorithms are presented, together with a discussion of the pros and cons of each algorithm and the challenging issues, and special attention is paid to the use of sub-Nyquist techniques, including compressive sensing and multichannel sub- Nyquist sampling.
Abstract: Cognitive radio has emerged as one of the most promising candidate solutions to improve spectrum utilization in next generation cellular networks. A crucial requirement for future cognitive radio networks is wideband spectrum sensing: secondary users reliably detect spectral opportunities across a wide frequency range. In this article, various wideband spectrum sensing algorithms are presented, together with a discussion of the pros and cons of each algorithm and the challenging issues. Special attention is paid to the use of sub-Nyquist techniques, including compressive sensing and multichannel sub- Nyquist sampling techniques.
536 citations
TL;DR: A review of the history of wireless power transfer and its recent developments is given to show how such technologies can be applied to sensor networks and address their energy constraints.
Abstract: Energy constraints are widely regarded as a fundamental limitation of wireless and mobile devices. For sensor networks, a limited lifetime due to battery constraint poses a performance bottleneck and barrier for large scale deployment. Recently, wireless power transfer has emerged as a promising technology to address energy and lifetime bottlenecks in a sensor network. In this article, we give a review of the history of wireless power transfer and describe its recent developments. We show how such technologies can be applied to sensor networks and address their energy constraints.
473 citations
TL;DR: The results quantify the delays to be expected in practice when Wi-Fi Direct devices discover each other and establish a connection, and the performance of its novel power saving protocols.
Abstract: Wi-Fi Direct is a new technology defined by the Wi-Fi Alliance aimed at enhancing direct device to device communications in Wi-Fi. Thus, given the wide base of devices with Wi-Fi capabilities, and the fact that it can be entirely implemented in software over traditional Wi-Fi radios, this technology is expected to have a significant impact. In this article we provide a thorough overview of the novel functionalities defined in Wi-Fi Direct, and present an experimental evaluation that portrays the performance to be expected in real scenarios. In particular, our results quantify the delays to be expected in practice when Wi-Fi Direct devices discover each other and establish a connection, and the performance of its novel power saving protocols. To the best of the authors? knowledge this is the first article in the state of the art that provides a wide overview and experimental evaluation of Wi-Fi Direct.
456 citations
Journal Article•
427 citations
TL;DR: A novel resource allocation scheme based on a column generation method for D2D communications in LTE-Advanced networks is introduced to maximize the spectrum utilization by finding the minimum transmission length in terms of time slots while protecting the cellular users from harmful interference and guaranteeing the QoS of D1D links.
Abstract: The Long Term Evolution-Advanced (LTEAdvanced) networks are being developed to provide mobile broadband services for the fourth generation (4G) cellular wireless systems. Deviceto- device (D2D) communications is a promising technique to provide wireless peer-to-peer services and enhance spectrum utilization in the LTE-Advanced networks. In D2D communications, the user equipments (UEs) are allowed to directly communicate between each other by reusing the cellular resources rather than using uplink and downlink resources in the cellular mode when communicating via the base station. However, enabling D2D communications in a cellular network poses two major challenges. First, the interference caused to the cellular users by D2D devices could critically affect the performances of the cellular devices. Second, the minimum quality-of-service (QoS) requirements of D2D communications need to be guaranteed. In this article, we introduce a novel resource allocation scheme (i.e. joint resource block scheduling and power control) for D2D communications in LTE-Advanced networks to maximize the spectrum utilization while addressing the above challenges. First, an overview of LTE-Advanced networks, and architecture and signaling support for provisioning of D2D communications in these networks are described. Furthermore, research issues and the current state-of-the-art of D2D communications are discussed. Then, a resource allocation scheme based on a column generation method is proposed for D2D communications. The objective is to maximize the spectrum utilization by finding the minimum transmission length in terms of time slots for D2D links while protecting the cellular users from harmful interference and guaranteeing the QoS of D2D links. The performance of this scheme is evaluated through simulations.
419 citations
TL;DR: This article makes the first attempt to present a survey of mobile cloud computing from the perspective of its intended usages, and introduces three common mobile cloud architectures and classify comprehensive existing work into two fundamental categories: computation offloading and capability extending.
Abstract: Mobile cloud computing, with its promise to meet the urgent need for richer applications and services of resource-constrained mobile devices, is emerging as a new computing paradigm and has recently attracted significant attention. However, there is no clear definition and no well defined scope for mobile cloud computing due to commercial hype, and diverse ways of combining cloud computing and mobile applications. This article makes the first attempt to present a survey of mobile cloud computing from the perspective of its intended usages. Specifically, we introduce three common mobile cloud architectures and classify comprehensive existing work into two fundamental categories: computation offloading and capability extending. Considering the energy bottleneck and user context of mobile devices, we discuss the research challenges and opportunities of introducing cloud computing to assist mobile devices, including energy-efficient interactions, virtual machine migration overhead, privacy, and security. Moreover, we demonstrate three real-world applications enabled by mobile cloud computing, in order to stimulate further discussion and development of this emerging field.
343 citations
TL;DR: A survey of mobile data offloading technologies including insights from the business perspective as well is provided.
Abstract: Over the last few years, data traffic over cellular networks has seen an exponential rise, primarily due to the explosion of smartphones, tablets, and laptops This increase in data traffic on cellular networks has caused an immediate need for offloading traffic for optimum performance of both voice and data services As a result, different innovative solutions have emerged to manage data traffic Some of the key technologies include Wi-Fi, femtocells, and IP flow mobility The growth of data traffic is also creating challenges for the backhaul of cellular networks; therefore, solutions such as core network offloading and media optimization are also gaining popularity This article aims to provide a survey of mobile data offloading technologies including insights from the business perspective as well
320 citations
TL;DR: This article surveys the state of the art of spectrum prediction in cognitive radio networks, summarize the major spectrum prediction techniques, illustrate their applications, and present the relevant open research challenges.
Abstract: Spectrum sensing, spectrum decision, spectrum sharing, and spectrum mobility are four major functions of cognitive radio systems. Spectrum sensing is utilized to observe the spectrum occupancy status and recognize the channel availability, while CR users dynamically access the available channels through the regulation processes of spectrum decision, spectrum sharing, and spectrum mobility. To alleviate the processing delays involved in these four functions and to improve the efficiency of spectrum utilization, spectrum prediction for cognitive radio networks has been extensively studied in the literature. This article surveys the state of the art of spectrum prediction in cognitive radio networks. We summarize the major spectrum prediction techniques, illustrate their applications, and present the relevant open research challenges.
263 citations
TL;DR: Evaluating three state-of-the-art FFR deployment schemes for OFDMA-based two-tier HetNets comprising macrocells overlaid with femtocells shows that, the average gains in spectral efficiency of the network are significantly higher for the proposed scheme when compared to the strict F FR, soft FFR, and FFR-3 schemes.
Abstract: Improvement of cell coverage and network capacity are two major challenges for the evolving 4G cellular wireless communication networks such as LTE-Advanced networks. In this context, hierarchical layering of cells with macro base stations coexisting with low-power and shortrange base stations (corresponding to picocells or femtocells) in a service area is considered to be an efficient solution to enhance the spectralefficiency of the network per unit area. Also, such a hierarchical cell deployment, which is referred to as a heterogeneous network, or Het- Net, provides significant improvement in the coverage of indoor and cell edge users and ensures better QoS to the users. Interference mitigation between different layers is one of the key issues that needs to be resolved for successful deployment of HetNets. To this end, fast frequency response, FFR, is considered to be an efficient intercell interference coordination technique for OFDMA-based HetNets. This article focuses on evaluating three state-of-the-art FFR deployment schemes: strict FFR, soft FFR, and FFR-3 schemes for OFDMA-based two-tier HetNets comprising macrocells overlaid with femtocells. Also, a variation of the FFR-3 scheme, which is referred to as the optimal static FFR (OSFFR) scheme, is proposed. A broad comparison among all these FFR schemes is performed by using Monte Carlo simulations considering performance metrics such as outage probability, average network sum rate, and spectral efficiency. Simulation results show that, the average gains in spectral efficiency (b/s/Hz) of the network are significantly higher for the proposed scheme when compared to the strict FFR, soft FFR, and FFR-3 schemes.
241 citations
TL;DR: An overview of the concept of interference alignment as well as an assessment of practical issues including performance in realistic propagation environments, the role of channel state information at the transmitter, and the practicality of interference aligning in large networks are provided.
Abstract: Interference alignment is a revolutionary wireless transmission strategy that reduces the impact of interference. The idea of interference alignment is to coordinate multiple transmitters so that their mutual interference aligns at the receivers, facilitating simple interference cancellation techniques. Since interference alignment's inception, researchers have investigated its performance and proposed several improvements. Research efforts have been primarily focused on verifying interference alignment's ability to achieve the maximum degrees of freedom (an approximation of sum capacity), developing algorithms for determining alignment solutions, and designing transmission strategies that relax the need for perfect alignment but yield better performance. This article provides an overview of the concept of interference alignment as well as an assessment of practical issues including performance in realistic propagation environments, the role of channel state information at the transmitter, and the practicality of interference alignment in large networks.
TL;DR: A Graphic User Interface has been implemented to suggest a series of exercises to improve a sportsman/woman s condition, depending on the context and their profile.
Abstract: Applications based on Wireless Sensor Networks for Internet of Things scenarios are on the rise. The multiple possibilities they offer have spread towards previously hard to imagine fields, like e-health or human physiological monitoring. An application has been developed for its usage in scenarios where data collection is applied to smart spaces, aiming at its usage in fire fighting and sports. This application has been tested in a gymnasium with real, non-simulated nodes and devices. A Graphic User Interface has been implemented to suggest a series of exercises to improve a sportsman/woman s condition, depending on the context and their profile. This system can be adapted to a wide variety of e-health applications with minimum changes, and the user will interact using different devices, like smart phones, smart watches and/or tablets.
TL;DR: In this article, a survey of cognitive radio functionalities with self-organization features is presented, including critical functionalities of MAC and network-layer operations, including common control channel management, cooperative spectrum sensing, bioinspired spectrum sharing, network scalability and adaptive routing.
Abstract: Cognitive radio is regarded as a promising technology to provide high bandwidth to mobile users via heterogeneous wireless network architectures and dynamic spectrum access techniques. However, cognitive radio networks may also impose some challenges due to various factors such as the ever increasing complexity of network architecture, the high cost of configuring and managing large-scale networks, the fluctuating nature of the available spectrum, diverse QoS requirements of various applications, and the intensifying difficulties of centralized control. A plethora of work has been carried out to address the challenges aforementioned by employing cognitive radio functionalities with self-organization features. In this article, variant aspects of selforganization paradigms in cognitive radio networks, including critical functionalities of MACand network-layer operations, are surveyed. The main contributions of this survey include introducing the fundamentals of existing cognitive radio and self-organization techniques as well as their current progress, surveying critical cognitive radio issues (including common control channel management, cooperative spectrum sensing, bioinspired spectrum sharing, network scalability and adaptive routing) as well as their self-organization features, and identifying new directions and open problems in cognitive radio networks.
TL;DR: The views on the evolution concept and candidate technologies for future steps of LTE-A taking into account the ever increasing importance of local area (small cells) and the need for further spectrum extension to higher frequency bands are presented.
Abstract: In the future steps of 3GPP LTE-Advanced, we will need to ensure the sustainability of 3GPP radio access technologies in order to respond to the anticipated challenging requirements of the future. To this end, this article presents our views on the evolution concept and candidate technologies for future steps of LTE-A taking into account the ever increasing importance of local area (small cells) and the need for further spectrum extension to higher frequency bands. In our evolution concept, we emphasize the integration of the local area with the wide area as a new form of cooperation between conventional macrocells in lower frequency bands and small cells deployed in higher frequency bands. Furthermore, we identify the potential key technologies for further spectrum efficiency enhancements for both the local area and the wide area, and for the efficient integration of the local and wide areas while assuming frequency separation between macrocells and small cells. In particular, multicell cooperation based on macrocell assistance of small cells (referred to as Phantom cell) is introduced, and the related benefits are discussed. Finally, in order to demonstrate the potential capacity gains of our evolution concept, system-level simulation results are provided for using outdoor small cells in higher/wider frequency bands.
TL;DR: The framework of HetNet for MCC is introduced, identifying the main functional blocks and the current state of the art techniques for each functional block, and the challenges for supporting MCC applications in Het net under this proposed framework are discussed.
Abstract: Mobile cloud computing (MCC) is an appealing paradigm enabling users to enjoy the vast computation power and abundant network services ubiquitously with the support of remote cloud. However, the wireless networks and mobile devices have to face many challenges due to the limited radio resources, battery power and communications capabilities, which may significantly impede the improvement of service qualities. Heterogeneous Network (HetNet), which has multiple types of low power radio access nodes in addition to the traditional macrocell nodes in a wireless network, is widely accepted as a promising way to satisfy the unrelenting traffic demand. In this article, we first introduce the framework of HetNet for MCC, identifying the main functional blocks. Then, the current state of the art techniques for each functional block are briefly surveyed, and the challenges for supporting MCC applications in HetNet under our proposed framework are discussed. We also envision the future for MCC in HetNet before drawing the conclusion.
TL;DR: A joint opportunistic interference avoidance scheme with Gale-Shapley spectrum sharing (GSOIA) based on the interweave paradigm to mitigate both tier interferences in macro/femto heterogeneous networks.
Abstract: Femtocells have emerged as a promising solution to provide wireless broadband access coverage in cellular dead zones and indoor environments. Compared with other techniques for indoor coverage, femtocells achieve better user experience with less capital expenditure and maintenance cost. However, co-channel deployments of closed subscriber group femtocells cause coverage holes in macrocells due to co-channel interference. To address this problem, cognitive radio technology has been integrated with femtocells. CR-enabled femtocells can actively sense their environment and exploit the network side information obtained from sensing to adaptively mitigate interference. We investigate three CRenabled interference mitigation techniques, including opportunistic interference avoidance, interference cancellation, and interference alignment. Macrocell activities can be obtained without significant overhead in femtocells. In this article, we present a joint opportunistic interference avoidance scheme with Gale-Shapley spectrum sharing (GSOIA) based on the interweave paradigm to mitigate both tier interferences in macro/femto heterogeneous networks. In this scheme, cognitive femtocells opportunistically communicate over available spectrum with minimal interference to macrocells; different femtocells are assigned orthogonal spectrum resources with a one-to-one matching policy to avoid intratier interference. Our simulations show considerable performance improvement of the GSOIA scheme and validate the potential benefits of CRenabled femtocells for in-home coverage.
TL;DR: This article introduces traffic-intensity-aware multicell cooperation, which adapts the network layout of cellular networks according to user traffic demands in order to reduce the number of active base stations and investigates improving the energy efficiency of Cellular networks by exploiting coordinated multipoint transmissions.
Abstract: Recently, green communications has received much attention. Cellular networks are among the major energy hoggers of communication networks, and their contributions to the global energy consumption increase fast. Therefore, greening cellular networks is crucial to reducing the carbon footprint of information and communications technology. In this article, we overview the multicell cooperation solutions for improving the energy efficiency of cellular networks. First, we introduce traffic-intensity-aware multicell cooperation, which adapts the network layout of cellular networks according to user traffic demands in order to reduce the number of active base stations. Then we discuss energy-aware multicell cooperation, which offloads traffic from on-grid base stations to off-grid base stations powered by renewable energy, thereby reducing the on-grid power consumption. In addition, we investigate improving the energy efficiency of cellular networks by exploiting coordinated multipoint transmissions. Finally, we discuss the characteristics of future cellular networks, and the challenges in achieving energy-efficient multicell cooperation in future cellular networks.
TL;DR: An overview of downlink CoMP techniques specified in 3GPP LTE Rel-11 focuses on transmission schemes, channel state information reporting, interference measurement, and reference signal design, and Evaluation results are provided to show the efficiency of CoMP.
Abstract: Intercell interference management has become a critical issue for future cellular mobile systems. Coordinated multipoint transmission/reception, or CoMP, is an effective way of managing intercell interference, and has been regarded as a key technology of LTE-Advanced. This article first provides an overview of downlink CoMP techniques specified in 3GPP LTE Rel-11, which mainly focuses on transmission schemes, channel state information reporting, interference measurement, and reference signal design. Then uplink CoMP is discussed in brief as most of the coordination gain can be achieved by implementation with little standardization support. Evaluation results are provided to show the efficiency of CoMP. The challenges as well as possible solutions for future CoMP standardization are also discussed.
TL;DR: Two emerging standards likely to shake the wireless world are introduced, namely IEEE 802.11ac and IEEE802.11ad, and the challenges in the path of multi-gigabit WiFi are identified.
Abstract: The advent of bandwidth-hungry wireless applications such as large file transfer, high definition video streaming, wireless display, and cellular data offload highlight the impending need for larger bandwidth and super speed WiFi links exceeding 1 Gb/s. This article introduces two emerging standards likely to shake the wireless world, namely IEEE 802.11ac and IEEE 802.11ad, and identifies the challenges in the path of multi-gigabit WiFi. We study the suitability of these standards for the new usage models enlisted in this article.
TL;DR: The need for novel cloud architectures and migration mechanisms that effectively bring the computing power of the cloud closer to the mobile user is advocated.
Abstract: Contemporary mobile devices generate heavy loads of computationally intensive tasks, which cannot be executed locally due to the limited processing and energy capabilities of each device. Cloud facilities enable mobile devices-clients to offload their tasks to remote cloud servers, giving birth to Mobile Cloud Computing (MCC). The challenge for the cloud is to minimize the task execution and data transfer time to the user, whose location changes due to mobility. However, providing quality of service guarantees is particularly challenging in the dynamic MCC environment, due to the time-varying bandwidth of the access links, the ever changing available processing capacity at each server and the timevarying data volume of each virtual machine. In this article, we advocate the need for novel cloud architectures and migration mechanisms that effectively bring the computing power of the cloud closer to the mobile user. We consider a cloud computing architecture that consists of a back-end cloud and a local cloud, which is attached to wireless access infrastructure (e.g. LTE base stations). We outline different classes of task migration policies, spanning fully uncoordinated ones, in which each user or server autonomously makes its migration decisions, up to the cloud-wide migration strategy of a cloud provider. We conclude with a discussion of open research problems in the area.
TL;DR: This article reviews mobile cloud computing, with focus on the technical challenges of MCC for multimedia applications, and briefly review the prototypes.
Abstract: By leveraging Mobile Cloud Computing (MCC), resource-poor mobile devices are enabled to run rich media applications. In this article, we review mobile cloud computing, with focus on the technical challenges of MCC for multimedia applications, and briefly review the prototypes. The article is concluded with a discussion of several open research problems that call for substantial research efforts.
TL;DR: This study investigates different service provision scenarios and proposes both time domain and frequency domain overlay cognitive radio OFDM systems for next generation cellular networks and shows the proposed schemes can achieve satisfying performance in different use cases.
Abstract: In this study, we integrate overlay cognitive radio technology into 4G cellular networks for the sharing of TV spectrum. On one hand, OFDM is a promising technique for high-speed data transmission over multipath fading channels and has been considered to be the best candidate for 4G mobile networks. On another hand, the overlay cognitive radio model makes it possible to have two concurrent transmissions in a given interference region, where conventionally only one communication takes place at a given time. We investigate different service provision scenarios and propose both time domain and frequency domain overlay cognitive radio OFDM systems for next generation cellular networks. Numerical results show our proposed schemes can achieve satisfying performance in different use cases.
TL;DR: The features of CoMP systems and channels that are distinct from single-cell multi-antenna systems are discussed and state-of-the-art approaches for coping with the factors that limit the potential are given.
Abstract: Coordinated multipoint, or CoMP, transmission has been recognized as a spectrally efficient technique for full frequency reuse cellular systems, in which base stations cooperate to reduce or eliminate intercell interference. However, there are still many obstacles before it can be put into practical use. In this article, we first discuss the features of CoMP systems and channels that are distinct from single-cell multi-antenna systems. We then give an overview of state-of-the-art approaches for coping with the factors that limit the potential of CoMP. A major issue is the acquisition of channel state information, which creates different challenges for TDD and FDD systems. Another set of challenges arises from the limited capacity available on the backhaul connections between the cooperating base stations. Both the fundamentals of possible solutions and their relations to cellular standards are discussed.
TL;DR: This article recommends the use of enhanced interference coordination, or eICIC, to mitigate cross-tier interference and ensure sufficient offload of users from macro to small cells in LTE-Advanced heterogeneous network scenarios with macro and small cells.
Abstract: In this article we present two promising practical use cases for simple multicell cooperation for LTE-Advanced heterogeneous network scenarios with macro and small cells. For co-channel deployment cases, we recommend the use of enhanced interference coordination, or eICIC, to mitigate cross-tier interference and ensure sufficient offload of users from macro to small cells. It is shown how the eICIC benefit is maximized by using a distributed inter-base station control framework for dynamic adjustment of essential parameters. Second, for scenarios where macro and small cells are deployed at different carriers an efficient use of the fragmented spectrum can be achieved by using collaborative inter-site carrier aggregation. In addition to distributed coordination/collaboration between base station nodes, the importance of explicit terminal assistance is highlighted. Comprehensive system-level simulation results illustrate the performance benefits of the presented techniques.
TL;DR: A number of critical challenges from the wireless technology and networking perspectives are addressed to efficiently support realtime and non-real-time traffic, intelligent data filtering, and fusion to reduce redundancy and minimize network traffic while ensuring information integrity, optimal network design, and, finally, security concerns.
Abstract: This article begins with a comprehensive presentation of architecture and essential characteristics of a smart grid communication network (SGCN). Then different types of traffic that an SGCN is anticipated to carry are studied along with their QoS requirements. Subsequently, a number of critical challenges from the wireless technology and networking perspectives are addressed. They include wireless mesh routing and QoS provisioning to efficiently support realtime and non-real-time traffic, intelligent data filtering, and fusion to reduce redundancy and minimize network traffic while ensuring information integrity, optimal network design, and, finally, security concerns.
TL;DR: It is shown that, despite the importance of context-awareness in WBAN applications, there are limited solutions available, particularly at the MAC layer, and a discussion on open research challenges for future context-aware WBANs is held.
Abstract: Wireless Body Area Network (WBAN) applications help reduce medical costs and improve people's quality of life by monitoring a user's biological signals via wearable and implantable wireless sensors. In order to satisfy burgeoning requirements, context-aware solutions are needed, thus allowing the system to adapt to changes in the user's mood, mental states, biological signals, and the environment. Thus, contextual information must be measured alongside biological signals in order to characterize and understand the current situation to adapt the system. With these issues in mind, this survey presents an overview of context-aware solutions at the Medium Access Control (MAC) and application layers. A clear distinction between medical and non-medical applications is made and some promising latest commercial WBAN products are highlighted. We show that, despite the importance of context-awareness in WBAN applications, there are limited solutions available, particularly at the MAC layer. The survey concludes with a discussion on open research challenges for future context-aware WBANs.
TL;DR: The network controlled time-domain enhanced inter-cell interference coordination (eICIC) concept is outlined by explaining the benefits and characteristics of this solution and the benefits of using advanced terminal device receiver architectures with interference suppression capabilities are motivated.
Abstract: Different technical solutions and innovations are enabling the move from macro-only scenarios towards heterogeneous networks with a mixture of different base station types. In this article we focus on multi-layer LTE-Advanced networks, and especially address aspects related to interference management. The network controlled time-domain enhanced inter-cell interference coordination (eICIC) concept is outlined by explaining the benefits and characteristics of this solution. The benefits of using advanced terminal device receiver architectures with interference suppression capabilities are motivated. Extensive system level performance results are presented with bursty traffic to demonstrate the eICIC concepts ability to dynamically adapt according to the traffic conditions.
TL;DR: Following each kind of security and privacy challenge, a series of basic and sophisticated cyber attacks are defined and substantial and promising solutions are given to satisfy the uniqueSecurity and privacy requirements in m-healthcare social networks.
Abstract: M-healthcare mobile social network has emerged as a promising next-generation healthcare system increasingly adopted by the US and European governments, with the rapid development of sensor and wireless communication technologies. In this paper, we describe the goals and tactics, and present a distributed architecture of m-healthcare social networks. Following each kind of security and privacy challenge, we define a series of basic and sophisticated cyber attacks and give substantial and promising solutions to satisfy the unique security and privacy requirements in m-healthcare social networks. Last but not least, several interesting open problems are pointed out with possible addressing ideas to trigger more research efforts in this emerging area.
TL;DR: Both simulation and laboratory testing results show that applying LTECR in TVWS can achieve satisfactory performance, and detailed key technologies that enable LTE-CR in the TV white space (TVWS), and related standards and regulation progresses are presented.
Abstract: Wireless data traffic is growing extraordinarily, with new wireless devices such as smartphones and bandwidth-demanding wireless applications such as video streaming becoming increasingly popular and widely adopted. Correspondingly, we have also witnessed the phenomenal wireless technology evolutions to support higher system capacities from generation to generation. Long Term Evolution has been developed as a 4G wireless technology that can support next generation multimedia applications with high capacity and high mobility needs. However, the peak data rate from 3G UMTS to 4G LTE-Advanced only increases 55 percent annually, while global mobile traffic has increased 66 times with an annual growth rate of 131 percent between 2008 and 2013. Clearly, there is a huge gap between the growth rate of the new air interface and the growth rate of customers? needs. A promising way to alleviate the contention between the actual traffic demands and the actual system capacity growth is to exploit more available spectrum resources. Recently, cognitive radio technology has been under extensive research and study. It aims to provide abundant new spectrum opportunities by exploiting underutilized or unutilized spectrum opportunistically. In this article, we discuss the technical solutions to expand LTE spectrum with CR technology (LTE-CR), and survey the advances in LTE-CR from both research and implementation aspects. We present detailed key technologies that enable LTE-CR in the TV white space (TVWS), and related standards and regulation progresses. To demonstrate the feasibility of deploying LTECR in TVWS, we have conducted extensive system-level simulations and also developed a LTE-CR prototype. Both simulation and laboratory testing results show that applying LTECR in TVWS can achieve satisfactory performance.
TL;DR: Simulation results validate that the proposed approach can effectively double the battery lifetimes of MTs, while successfully eliminating selfish players from cooperative groups.
Abstract: Multi-standard mobile terminals (MTs) are the trend of current and future mobile devices for taking advantage of heterogeneous integration of wireless access networks and providing ubiquitous connectivity and better quality of service. Holding multiple active interfaces, however, incurs significant power consumption burdens to MTs. This not only increases the carbon footprint of MTs but also makes the batteries of MTs deplete rapidly. Consequently, mobile users may have to relentlessly look for power outlets to charge their devices, which may threaten their true mobility freedom. To this end, in this article, we propose a promising approach based on coalition formation game and inter-terminal cooperation. Our innovative approach motivates MTs to cooperate, while addressing the issue of isolating selfish players. MTs assess radio channels and disseminate the acquired information as well as their available resources to sketch a global view of the radio environment. Based on this view, coalitions are formed whenever energy saving is foreseeable. Within a coalition, MTs pool their resources and perform their tasks cooperatively to maximize their energy efficiency. Simulation results validate that the proposed approach can effectively double the battery lifetimes of MTs, while successfully eliminating selfish players from cooperative groups.