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Radio Irregularity Model in OMNeT++. (arXiv:1709.07035v1 [cs.NI])

Vie, 09/22/2017 - 07:00

Radio irregularity is a non-negligible phenomenon that has an impact on protocol performances. For instance, irregularity in radio range leads to asymmetric links that cause the loss of packets in different directions. In order to investigate its effect, the Radio Irregularity Model (RIM) is proposed that takes into account the irregularity of a radio range and estimates path losses in an anisotropic environment. The purpose of this paper is to provide details of the RIM model developed in the INET Framework of the OMNeT++ simulator that can be used to investigate the impact of radio irregularity on protocol performance.

Categorías: research

Max-Min Fair Millimetre-Wave Backhauling. (arXiv:1709.07078v1 [cs.NI])

Vie, 09/22/2017 - 07:00

5G mobile networks are expected to provide pervasive high speed wireless connectivity, to support increasingly resource intensive user applications. Network hyper-densification therefore becomes necessary, though connecting to the Internet tens of thousands of base stations is non-trivial, especially in urban scenarios where optical fibre is difficult and costly to deploy. The millimetre wave (mm-wave) spectrum is a promising candidate for inexpensive multi-Gbps wireless backhauling, but exploiting this band for effective multi-hop data communications is challenging. In particular, resource allocation and scheduling of very narrow transmission/ reception beams requires to overcome terminal deafness and link blockage problems, while managing fairness issues that arise when flows encounter dissimilar competition and traverse different numbers of links with heterogeneous quality. In this paper, we propose WiHaul, an airtime allocation and scheduling mechanism that overcomes these challenges specific to multi-hop mm-wave networks, guarantees max-min fairness among traffic flows, and ensures the overall available backhaul resources are fully utilised. We evaluate the proposed WiHaul scheme over a broad range of practical network conditions, and demonstrate up to 5 times individual throughput gains and a fivefold improvement in terms of measurable fairness, over recent mm-wave scheduling solutions.

Categorías: research

A Deep-Reinforcement Learning Approach for Software-Defined Networking Routing Optimization. (arXiv:1709.07080v1 [cs.NI])

Vie, 09/22/2017 - 07:00

In this paper we design and evaluate a Deep-Reinforcement Learning agent that optimizes routing. Our agent adapts automatically to current traffic conditions and proposes tailored configurations that attempt to minimize the network delay. Experiments show very promising performance. Moreover, this approach provides important operational advantages with respect to traditional optimization algorithms.

Categorías: research

Covert Wireless Communication with Artificial Noise Generation. (arXiv:1709.07096v1 [cs.IT])

Vie, 09/22/2017 - 07:00

Covert communication conceals the transmission of the message from an attentive adversary. Recent work on the limits of covert communication in additive white Gaussian noise (AWGN) channels has demonstrated that a covert transmitter (Alice) can reliably transmit a maximum of $\mathcal{O}\left(\sqrt{n}\right)$ bits to a covert receiver (Bob) without being detected by an adversary (Warden Willie) in $n$ channel uses. This paper focuses on the scenario where other friendly nodes distributed according to a two-dimensional Poisson point process with density $m$ are present in the environment. We propose a strategy where the friendly node closest to the adversary, without close coordination with Alice, produces artificial noise. We show that this method allows Alice to reliably and covertly send $\mathcal{O}(\min\{{n,m^{\gamma/2}\sqrt{n}}\})$ bits to Bob in $n$ channel uses, where $\gamma$ is the path-loss exponent. Moreover, we also consider a setting where there are $N_{\mathrm{w}}$ collaborating adversaries uniformly and randomly located in the environment and show that in $n$ channel uses, Alice can reliably and covertly send $\mathcal{O}\left(\min\left\{n,\frac{m^{\gamma/2} \sqrt{n}}{N_{\mathrm{w}}^{\gamma}}\right\}\right)$ bits to Bob when $\gamma >2$, and $\mathcal{O}\left(\min\left\{n,\frac{m \sqrt{n}}{N_{\mathrm{w}}^{2}\log^2 {N_{\mathrm{w}}}}\right\}\right)$ when $\gamma = 2$. Conversely, under mild restrictions on the communication strategy, we demonstrate that no higher covert throughput is possible for $\gamma>2$.

Categorías: research

Modeling and Quantifying the Forces Driving Online Video Popularity Evolution. (arXiv:1709.07130v1 [cs.SI])

Vie, 09/22/2017 - 07:00

Video popularity is an essential reference for optimizing resource allocation and video recommendation in online video services. However, there is still no convincing model that can accurately depict a video's popularity evolution. In this paper, we propose a dynamic popularity model by modeling the video information diffusion process driven by various forms of recommendation. Through fitting the model with real traces collected from a practical system, we can quantify the strengths of the recommendation forces. Such quantification can lead to characterizing video popularity patterns, user behaviors and recommendation strategies, which is illustrated by a case study of TV episodes.

Categorías: research

Analysis of Wireless-Powered Device-to-Device Communications with Ambient Backscattering. (arXiv:1709.07182v1 [cs.NI])

Vie, 09/22/2017 - 07:00

Self-sustainable communications based on advanced energy harvesting technologies have been under rapid development, which facilitate autonomous operation and energy-efficient transmission. Recently, ambient backscattering that leverages existing RF signal resources in the air has been invented to empower data communication among low-power devices. In this paper, we introduce hybrid device-to-device (D2D) communications by integrating ambient backscattering and wireless-powered communications. The hybrid D2D communications are self-sustainable, as no dedicated external power supply is required. However, since the radio signals for energy harvesting and backscattering come from external RF sources, the performance of the hybrid D2D communications needs to be optimized efficiently. As such, we design two mode selection protocols for the hybrid D2D transmitter, allowing a more flexible adaptation to the environment. We then introduce analytical models to characterize the impacts of the considered environment factors, e.g., distribution, spatial density, and transmission load of the ambient transmitters, on the hybrid D2D communications performance. Extensive simulations show that the repulsion factor among the ambient transmitters has a non-trivial impact on the communication performance. Additionally, we reveal how different mode selection protocols affect the performance metrics.

Categorías: research

Cyber Insurance for Heterogeneous Wireless Networks. (arXiv:1709.07198v1 [cs.NI])

Vie, 09/22/2017 - 07:00

Heterogeneous wireless networks (HWNs) composed of densely deployed base stations of different types with various radio access technologies have become a prevailing trend to accommodate ever-increasing traffic demand in enormous volume. Nowadays, users rely heavily on HWNs for ubiquitous network access that contains valuable and critical information such as financial transactions, e-health, and public safety. Cyber risks, representing one of the most significant threats to network security and reliability, are increasing in severity. To address this problem, this article introduces the concept of cyber insurance to transfer the cyber risk (i.e., service outage, as a consequence of cyber risks in HWNs) to a third party insurer. Firstly, a review of the enabling technologies for HWNs and their vulnerabilities to cyber risks is presented. Then, the fundamentals of cyber insurance are introduced, and subsequently, a cyber insurance framework for HWNs is presented. Finally, open issues are discussed and the challenges are highlighted for integrating cyber insurance as a service of next generation HWNs.

Categorías: research

User Association and Bandwidth Allocation for Terrestrial and Aerial Base Stations with Backhaul Considerations. (arXiv:1709.07356v1 [cs.NI])

Vie, 09/22/2017 - 07:00

Drone base stations (DBSs) can enhance network coverage and area capacity by moving supply towards demand when required. This degree of freedom could be especially useful for future applications with extreme demands, such as ultra reliable and low latency communications (uRLLC). However, deployment of DBSs can face several challenges. One issue is finding the 3D placement of such BSs to satisfy dynamic requirements of the system. Second, the availability of reliable wireless backhaul links and the related resource allocation are principal issues that should be considered. Finally, association of the users with BSs becomes an involved problem due to mobility of DBSs. In this paper, we consider a macro-BS (MBS) and several DBSs that rely on the wireless links to the MBS for backhauling. Considering regular and uRLLC users, we propose an algorithm to find efficient 3D locations of DBSs in addition to the user-BS associations and wireless backhaul bandwidth allocations to maximize the sum logarithmic rate of the users. To this end, a decomposition method is employed to first find the user-BS association and bandwidth allocations. Then DBS locations are updated using a heuristic particle swarm optimization algorithm. Simulation results show the effectiveness of the proposed method and provide useful insights on the effects of traffic distributions and antenna beamwidth.

Categorías: research

Wireless Information and Power Transfer: Nonlinearity, Waveform Design and Rate-Energy Tradeoff. (arXiv:1607.05602v3 [cs.IT] UPDATED)

Vie, 09/22/2017 - 07:00

The design of Wireless Information and Power Transfer (WIPT) has so far relied on an oversimplified and inaccurate linear model of the energy harvester. In this paper, we depart from this linear model and design WIPT considering the rectifier nonlinearity. We develop a tractable model of the rectifier nonlinearity that is flexible enough to cope with general multicarrier modulated input waveforms. Leveraging that model, we motivate and introduce a novel WIPT architecture relying on the superposition of multi-carrier unmodulated and modulated waveforms at the transmitter. The superposed WIPT waveforms are optimized as a function of the channel state information so as to characterize the rate-energy region of the whole system. Analysis and numerical results illustrate the performance of the derived waveforms and WIPT architecture and highlight that nonlinearity radically changes the design of WIPT. We make key and refreshing observations. First, analysis (confirmed by circuit simulations) shows that modulated and unmodulated waveforms are not equally suitable for wireless power delivery, namely modulation being beneficial in single-carrier transmissions but detrimental in multi-carrier transmissions. Second, a multicarrier unmodulated waveform (superposed to a multi-carrier modulated waveform) is useful to enlarge the rate-energy region of WIPT. Third, a combination of power splitting and time sharing is in general the best strategy. Fourth, a non-zero mean Gaussian input distribution outperforms the conventional capacity-achieving zero-mean Gaussian input distribution in multi-carrier transmissions. Fifth, the rectifier nonlinearity is beneficial to system performance and is essential to efficient WIPT design.

Categorías: research

Secure Virtual Network Embedding in a Multi-Cloud Environment. (arXiv:1703.01313v2 [cs.NI] UPDATED)

Vie, 09/22/2017 - 07:00

Recently-proposed virtualization platforms give cloud users the freedom to specify their network topologies and addressing schemes. These platforms have, however, been targeting a single datacenter of a cloud provider, which is insufficient to support (critical) applications that need to be deployed across multiple trust domains while enforcing diverse security requirements. This paper addresses this problem by presenting a novel solution for a central component of network virtualization -- the online network embedding, which finds efficient mappings of virtual networks requests onto the substrate network. Our solution considers security as a first class citizen, enabling the definition of flexible policies in three central areas: on the communications, where alternative security compromises can be explored (e.g., encryption); on the computations, supporting redundancy if necessary while capitalizing on hardware assisted trusted executions; across multiples clouds, including public and private facilities, with the associated trust levels. We formulate the solution as a Mixed Integer Linear Program (MILP), and evaluate our proposal against the most commonly used alternative. Our analysis gives insight into the trade-offs involved with the inclusion of security and trust into network virtualization, providing evidence that this notion may enhance profits under the appropriate cost models.

Categorías: research

Reverse Engineering Human Mobility in Large-scale Natural Disasters. (arXiv:1708.02151v2 [cs.NI] UPDATED)

Vie, 09/22/2017 - 07:00

Delay/Disruption-Tolerant Networks (DTNs) have been around for more than a decade and have especially been proposed to be used in scenarios where communication infrastructure is unavailable. In such scenarios, DTNs can offer a best-effort communication service by exploiting user mobility. Natural disasters are an important application scenario for DTNs when the cellular network is destroyed by natural forces. To assess the performance of such networks before deployment, we require appropriate knowledge of human mobility.

In this paper, we address this problem by designing, implementing, and evaluating a novel mobility model for large-scale natural disasters. Due to the lack of GPS traces, we reverse-engineer human mobility of past natural disasters (focusing on 2010 Haiti earthquake and 2013 Typhoon Haiyan) by leveraging knowledge of 126 experts from 71 Disaster Response Organizations (DROs). By means of simulation-based experiments, we compare and contrast our mobility model to other well-known models, and evaluate their impact on DTN performance. Finally, we make our source code available to the public.

Categorías: research

Unsupervised Machine Learning for Networking: Techniques, Applications and Research Challenges. (arXiv:1709.06599v1 [cs.NI])

Jue, 09/21/2017 - 06:00

While machine learning and artificial intelligence have long been applied in networking research, the bulk of such works has focused on supervised learning. Recently there has been a rising trend of employing unsupervised machine learning using unstructured raw network data to improve network performance and provide services such as traffic engineering, anomaly detection, Internet traffic classification, and quality of service optimization. The interest in applying unsupervised learning techniques in networking emerges from their great success in other fields such as computer vision, natural language processing, speech recognition, and optimal control (e.g., for developing autonomous self-driving cars). Unsupervised learning is interesting since it can unconstrain us from the need of labeled data and manual handcrafted feature engineering thereby facilitating flexible, general, and automated methods of machine learning. The focus of this survey paper is to provide an overview of the applications of unsupervised learning in the domain of networking. We provide a comprehensive survey highlighting the recent advancements in unsupervised learning techniques and describe their applications for various learning tasks in the context of networking. We also provide a discussion on future directions and open research issues, while also identifying potential pitfalls. While a few survey papers focusing on the applications of machine learning in networking have previously been published, a survey of similar scope and breadth is missing in literature. Through this paper, we advance the state of knowledge by carefully synthesizing the insights from these survey papers while also providing contemporary coverage of recent advances.

Categorías: research

A Load Balancing Algorithm for Resource Allocation in IEEE 802.15.4e Networks. (arXiv:1709.06835v1 [cs.NI])

Jue, 09/21/2017 - 06:00

The recently created IETF 6TiSCH working group combines the high reliability and low-energy consumption of IEEE 802.15.4e Time Slotted Channel Hopping with IPv6 for industrial Internet of Things. We propose a distributed link scheduling algorithm, called Local Voting, for 6TiSCH networks that adapts the schedule to the network conditions. The algorithm tries to equalize the link load (defined as the ratio of the queue length over the number of allocated cells) through cell reallocation. Local Voting calculates the number of cells to be added or released by the 6TiSCH Operation Sublayer (6top). Compared to a representative algorithm from the literature, Local Voting provides simultaneously high reliability and low end-to-end latency while consuming significantly less energy. Its performance has been examined and compared to On-the-fly algorithm in 6TiSCH simulator by modeling an industrial environment with 50 sensors.

Categorías: research

Towards Better Understanding of Bitcoin Unreachable Peers. (arXiv:1709.06837v1 [cs.NI])

Jue, 09/21/2017 - 06:00

The bitcoin peer-to-peer network has drawn significant attention from researchers, but so far has mostly focused on publicly visible portions of the network, i.e., publicly reachable peers. This mostly ignores the hidden parts of the network: unreachable Bitcoin peers behind NATs and firewalls. In this paper, we characterize Bitcoin peers that might be behind NATs or firewalls from different perspectives. Using a special-purpose measurement tool we conduct a large scale measurement study of the Bitcoin network, and discover several previously unreported usage patterns: a small number of peers are involved in the propagation of 89% of all bitcoin transactions, public cloud services are being used for Bitcoin network probing and crawling, a large amount of transactions are generated from only two mobile applications. We also empirically evaluate a method that uses timing information to re-identify the peer that created a transaction against unreachable peers. We find this method very accurate for peers that use the latest version of the Bitcoin Core client.

Categorías: research

Plugo: a VLC Systematic Perspective of Large-scale Indoor Localization. (arXiv:1709.06926v1 [cs.NI])

Jue, 09/21/2017 - 06:00

Indoor localization based on Visible Light Communication (VLC) has been in favor with both the academia and industry for years. In this paper, we present a prototyping photodiode-based VLC system towards large-scale localization. Specially, we give in-depth analysis of the design constraints and considerations for large-scale indoor localization research. After that we identify the key enablers for such systems: 1) distributed architecture, 2) one-way communication, and 3) random multiple access. Accordingly, we propose Plugo -- a photodiode-based VLC system conforming to the aforementioned criteria. We present a compact design of the VLC-compatible LED bulbs featuring plug-and-go use-cases. The basic framed slotted Additive Links On-line Hawaii Area (ALOHA) is exploited to achieve random multiple access over the shared optical medium. We show its effectiveness in beacon broadcasting by experiments, and further demonstrate its scalability to large-scale scenarios through simulations. Finally, preliminary localization experiments are conducted using fingerprinting-based methods in a customized testbed, achieving an average accuracy of 0.14 m along with a 90-percentile accuracy of 0.33 m.

Categorías: research

Mist Computing: Principles, Trends and Future Direction. (arXiv:1709.06927v1 [cs.NI])

Jue, 09/21/2017 - 06:00

In this paper we present the novel idea of computing near the edge of IOT architecture which enhances the inherent efficiency while computing complex applications. This concept is termed as mist computing. We believe this computing will bring about an massive revolution in future computing technologies. instead of thrusting the control responsibility to gateways while data transmission the control is decentralised to end nodes which decrease the communicational delay of the network thereby increasing the throughput.

Categorías: research

Level-Triggered Harvest-then-Consume Protocol with Two Bits or Less Energy State Information. (arXiv:1709.06928v1 [cs.NI])

Jue, 09/21/2017 - 06:00

We propose a variation of harvest-then-consume protocol with low complexity where the harvest and consume phases change when the battery energy level reaches certain thresholds. The proposed protocol allows us to control the possible energy outage during consumption phase. Assuming that the battery is perfect and that the energy arrival is a renewal process, we analyze the duty cycle and the operating cycle speed of the protocol. The proposed protocol also allows for limited battery energy state information. The cases when the system has two-bits, one-bit, and zero-bit of battery energy state information are studied in detail. Numerical simulations verify the obtained formulas.

Categorías: research

Paving the Way to Smart Micro Energy Internet: Concepts, Design Principles, and Engineering Practices. (arXiv:1612.09500v2 [math.OC] UPDATED)

Jue, 09/21/2017 - 06:00

Energy internet is one of the most promising future energy infrastructures which could enhance energy efficiency and improve operating flexibility from the energy point of view. In analog to the micro-grid, micro energy internet puts more emphasis on the distribution level and demand side. The concept and design principles of the smart micro energy internet are proposed to accommodate micro-grids, distributed poly-generation systems, energy storage facilities, and related energy distribution infrastructures. The dispatch and control system of the smart micro energy internet should be responsible for external disturbance and able to approach a satisfactory operating point which compromises multiple criteria, such as safety, economy, and environment protection. To realize the vision of the smart micro energy internet, engineering game theory based energy management system with self-approaching-optimum capability are investigated. Based on the proposed concepts and design principles, and energy management system, a prototype of the first domestic conceptual solar-based smart micro energy internet is initially established in Qinghai University.

Categorías: research

Modeling the Internet of Things: a simulation perspective. (arXiv:1707.00832v2 [cs.DC] UPDATED)

Jue, 09/21/2017 - 06:00

This paper deals with the problem of properly simulating the Internet of Things (IoT). Simulating an IoT allows evaluating strategies that can be employed to deploy smart services over different kinds of territories. However, the heterogeneity of scenarios seriously complicates this task. This imposes the use of sophisticated modeling and simulation techniques. We discuss novel approaches for the provision of scalable simulation scenarios, that enable the real-time execution of massively populated IoT environments. Attention is given to novel hybrid and multi-level simulation techniques that, when combined with agent-based, adaptive Parallel and Distributed Simulation (PADS) approaches, can provide means to perform highly detailed simulations on demand. To support this claim, we detail a use case concerned with the simulation of vehicular transportation systems.

Categorías: research

Reactive User Behavior and Mobility Models. (arXiv:1709.06395v1 [cs.NI])

Mié, 09/20/2017 - 05:00

In this paper, we present a set of simulation models to more realistically mimic the behaviour of users reading messages. We propose a User Behaviour Model, where a simulated user reacts to a message by a flexible set of possible reactions (e.g. ignore, read, like, save, etc.) and a mobility-based reaction (visit a place, run away from danger, etc.). We describe our models and their implementation in OMNeT++. We strongly believe that these models will significantly contribute to the state of the art of simulating realistically opportunistic networks.

Categorías: research