IMDEA Networks Institute Digital Repository
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1915 research outputs found
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TWINS: Time-of-flight based Wireless Indoor Navigation System
Get PDFWe introduce TWINS, Time-of-flight based Wireless Indoor
Navigation System, that estimates the position of commercial
off-the-shelf devices such as smartphones, tablets and laptops using pure commercial off-the-shelf WiFi Access Points in near real-time. TWINS is the result of several years of effort put into research and development. TWINS does not require any inertial sensors on the mobile devices, and it is based on a system that has participated in the 2014 and 2016 MSR Localization Competition editions.FALSEpu
60 GHz Networking: Mobility, Beamforming, and Frame Level Operation From Theory to Practice
Get PDFUnderstanding the gap between theory and practice of 60 GHz networks is crucial. Theoretical models typically focus on the physical layer only and assume ideal hardware components. However, such assumptions do not hold in practice. For instance, the cost-effective design of commercial off-the-shelf products often results in hardware impairments, such as highly irregular beam shapes. Further, mobility and frame aggregation have a strong impact throughout the protocol stack. Taking these effects into account when designing 60 GHz networking mechanisms is critical. In this paper, we characterize the aforementioned effects and contribute a comprehensive dataset of real-world traces that capture them. Among other traces, our dataset includes measurements of actual beam patterns, the impact of the cases of the devices on propagation, exhaustive measurements on the degradation of link performance in case of mobility, and the behavior of aggregation at the physical layer. Our dataset is the most comprehensive study of this kind to date. As a result, our work allows researchers to take the aforementioned hardware impairments into account, which paves the way for comparable and realistic evaluations of 60 GHz networking mechanisms in the community.pu
SEMPER: A Stateless Traffic Engineering Solution for WAN based on MP-TCP
Get PDFEnterprise Networking has a strong set of requirements in terms of resiliency, reliability and resources usage. With
current approaches being based on monolithic and expensive
infrastructures using dedicated overlay links, providers are
moving to more economical hybrid solutions that encompass
private dedicated links with public/regular Internet connections. However, these usually rely on complex, hardware-dependent and/or proprietary Traffic Engineering (TE) solutions, which are computationally costly, in particular for the forwarding nodes. In this paper, we propose SEMPER: a lightweight TE solution based on MP-TCP that, in contrast to other TE solutions, moves the complexity to the endpoints of the connection, and
relieves the forwarding elements from complex operations or even maintaining state. As our evaluation shows, SEMPER efficiently makes use of all available paths between the endpoints while maintaining fairness, and properly adapts to variations on them available capacity.TRUEpu
A NFV system to support configurable and automated multi-UAV service deployments
Get PDFIn this paper, we explore the strong potential of Network Function Virtualization (NFV) technologies to enable multi-mission small unmanned aircraft systems. In this context, we analyze the main challenges of using NFV technologies in this emergent field, and we present the design of an NFV system that supports the flexible, automated and cost-effective deployment of network services over small unmanned aerial vehicles. To validate our design, we implemented its most relevant components with open-source technologies, using this first prototype of the system to carry out a set of preliminary experiments that showcase its feasibility and functionality.TRUEpu
Optimizing the delivery of Multimedia over mobile networks
Get PDFThe consumption of multimedia content is moving from a residential environment to mobile phones. Mobile data traffic, driven mostly by video demand, is increasing rapidly and wireless spectrum is becoming a more and more scarce resource. This makes it highly important to operate mobile networks efficiently. To tackle this, recent developments in anticipatory networking schemes make it possible to predict the future capacity of mobile devices and optimize the allocation of the limited wireless resources. Further, optimizing Quality of Experience—smooth, quick, and high quality playback—is more difficult in the mobile setting, due to the highly dynamic nature of wireless links. A key requirement for achieving, both anticipatory networking schemes and QoE optimization, is estimating the available bandwidth of mobile devices. Ideally, this should be done quickly and with low overhead.
In summary, we propose a series of improvements to the delivery of multimedia over mobile networks. Our contributions include identifying inefficiencies in the interconnection of mobile operators with the servers hosting content, proposing an algorithm to opportunistically create frequent capacity estimations suitable for use in resource optimization solutions and proposing another algorithm able to estimate the bandwidth class of a device based on minimal traffic in order to identify the ideal streaming quality its connection may support before commencing playback.Telematics EngineeringUniversidad Carlos III de Madrid, Spainpu
High-Precision Design of Pedestrian Mobility for Smart City Simulators
Get PDFThe unprecedented growth of the population living in urban environments calls for a rational and sustainable urban development. Smart cities can fill this gap by providing the citizens with high-quality services through efficient use of Information and Communication Technology (ICT). To this end, active citizen participation with mobile crowdsensing (MCS) techniques is a becoming common practice. As MCS systems require wide participation, the development of large scale real testbeds is often not feasible and simulations are the only alternative solution. Modeling the urban environment with high precision is a key ingredient to obtain effective results. However, currently existing tools like OpenStreetMap (OSM) fail to provide sufficient levels of details.
In this paper, we apply a procedure to augment the precision (AOP) of the graph describing the street network provided by OSM. Additionally, we compare different mobility models that are synthetic and based on a realistic dataset originated from a well known MCS data collection campaign (ParticipAct). For the dataset, we propose two arrival models that determine the users’ arrivals and match the experimental contact distribution. Finally, we assess the scalability of AOP for different cities, verify popular metrics for human mobility and the precision of different arrival models.TRUEpu
Bug Fixes, Improvements,... and Privacy Leaks
Get PDFIs mobile privacy getting better or worse over time? In this paper, we address this question by studying privacy leaks from historical and current versions of 512 popular Android apps, covering 7,665 app releases over 8 years of app version history. Through automated and scripted interaction with apps and analysis of the network traffic they generate on real mobile devices, we identify how privacy changes over time for individual apps and in aggregate. We find several trends that include increased collection of personally identifiable information (PII) across app versions, slow adoption of HTTPS to secure the information sent to other parties, and a large number of third parties being able to link user activity and locations across apps. Interestingly, while privacy is getting worse in aggregate, we find that the privacy risk of individual apps varies greatly over time, and a substantial fraction of apps see little change or even improvement in privacy. Given these trends, we propose metrics for quantifying privacy risk and for providing this risk assessment proactively to help users balance the risks and benefits of installing new versions of apps.TRUEpu