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The Energy Saving Potential of Static and Adaptive Resource Provisioning in Dense Cellular Networks
Get PDFIn this paper we study static and dynamic approaches to energy efficiency in dense cellular networks, where interference is one of the main limiting factors. We consider the two main approaches to energy efficiency through adaptive management of the network capacity: Base station (BS) sleeping and cell zooming. We propose an analytic framework for the assessment of the energy efficiency potential of several joint planning and management strategies. Our approach is based on stochastic geometry tools, on an approximate but accurate model of interference, and on a detailed, measurement-driven power
model. For a given user density, we show how to derive the
optimal BS density, and the BS transmit power which minimizes the mean power consumption of the network, while achieving a target QoS level. Through numerical evaluations, we show the potential savings enabled by joint (and disjoint) optimization of transmit power and density of active BSs. For a realistic network scenario, our approach suggests that huge energy savings are achievable by combining sleeping and zooming. In addition, we show that a static strategy, based on carefully planning the density of installed BS and their transmit power, can achieve most of the benefits of capacity tuning achievable through either
sleeping or zooming. This result has a very high relevance for network operators, since it allows avoiding the feared decrease in operational lifetime which the daily switching of BS entails.TRUEpu
Network Slicing for Guaranteed Rate Services: Admission Control and Resource Allocation Games
Get PDFTechnologies that enable network slicing are expected to be a key component of next generation mobile networks. Their promise lies in enabling tenants (such as mobile operators and/or services) to reap the cost and performance benefits of sharing resources while retaining the ability to customize their own allocations. When employing dynamic sharing mechanisms, tenants may exhibit strategic behavior, optimizing their choices in response to those of other tenants. This paper analyzes dynamic sharing in network slicing when tenants support inelastic users with minimum rate requirements. We propose a NEtwork Slicing (NES) framework combining: 1) admission control; 2) resource allocation; and 3) user dropping. We model the network slicing system with admitted users as a NES game; this is a new class of game where the inelastic nature of the traffic may lead to dropping users whose requirements cannot be met. We show that, as long as admission control guarantees that slices can satisfy the rate requirements of all their users, this game possesses a Nash equilibrium. Admission control policies (a conservative and an aggressive one) are considered, along with a resource allocation scheme and a user dropping algorithm, geared at maintaining the system in Nash equilibria. We analyze our NES framework's performance in equilibrium, showing that it achieves the same or better utility than static resource partitioning, and bound the difference between NES and the socially optimal performance. Simulation results confirm the effectiveness of the proposed approach.TRUEpu
Admission Control in Shared Memory Switches
Get PDFCloud applications bring new challenges to the design of network elements, in particular the burstiness of traffic workloads. A shared memory switch is a good candidate architecture to exploit buffer capacity; in this work, we
analyze the performance of this architecture. Our goal is to explore the impact of additional traffic characteristics such as varying processing requirements and packet values on objective functions. The outcome of this work is a better understanding of the relevant parameters for buffer management to achieve better performance in dynamic environments of data centers. We consider a model that captures more of the properties of the target architecture than previous work and consider several scheduling and buffer management algorithms that are specifically designed to optimize its performance. In particular, we provide analytic guarantees for the throughput performance of our algorithms that are independent from specific distributions of packet arrivals. We furthermore report on a comprehensive simulation study which validates our analytic results.pu
OpenVLC1.2: Achieving Higher Throughput in Low-End Visible Light Communication Networks
Get PDFIn this paper, we introduce the OpenVLC1.2 research platform for low-end visible light communication (VLC) networks. The
platform builds on top of previous versions that has attracted dozens of users from the VLC research community.
We maintain its main advantages such as the support for communication with TCP/IP layers, software-based and
programmable MAC and PHY layers and low-cost front-end. In this new version, we make an effort to increase the network throughput to 100 kb/s, i.e. by a factor of 8 with respect to previous versions, without adding any hardware cost.
This benefit comes from our exploitation of the Programmable Real-time Units (PRUs) of the BeagleBone Black board, together with our low-resource consumption frame detection technique.TRUEpu
Stop and forward: Opportunistic local information sharing under walking mobility
Get PDFAvailable online since June 2018.In this paper we study an opportunistic geographically constrained information sharing paradigm known under the name Floating Content (FC), considering two different mobility models that describe the behavior of pedestrians. We assume that users carrying their smartphones walk from one location to another and then stop for a while. Information transfers take place in the periods when users pause between movements. We develop analytical models to compute the performance metrics that characterize FC in this case and we validate analytical results with data collected during an experiment performed in a university campus. The comparison proves the accuracy of our analytical models. Moreover, results unveil the key relevance for FC performance of group dynamics in user movements.pu
Connecting Battery-free IoT Tags Using LED Bulbs
Get PDFWe introduce BackVLC, a system to connect battery-free
IoT tags using LED bulbs. We make use of bulbs beyond
illumination. We send data to the tags with visible light communication (VLC), and retrofit the bulbs with simple circuitry to enable the uplink channel current VLC systems lack, using Radio Frequency (RF) backscatter communication from the tags. Tags process and send data, harvesting energy from light and radio. We present our system design and implementation, evaluate it in preliminary simulation studies and experiments, and discuss the research challenges to develop a complete network architecture. BackVLC is the first work that combines VLC with RF backscatter.TRUEpu
Underwater LiDAR Signal Processing for Enhanced Detection and Localization of Marine Life
Get PDFThe in situ detection, recognition and tracking of marine animal species is a very important step of field research in the domains of, among others, biology and ecology. Still, the direct observation of marine wildlife through equipment operating in the visible light spectrum is often impaired by the challenging conditions offered by ocean waters, where light can be subject to scattering and attenuation phenomena due to the water turbidity. As the use of powerful lighting may prove ineffective and even induce behavioral changes in marine animals, the design of minimally or non-invasive observation instruments becomes particularly important.
In this paper, we consider the serial Light Detection And Ranging (LiDAR) system under development at the Florida Atlantic University (FAU). This LiDAR design is based on inexpensive components and on low average power red lasers which are subject to significant attenuation in water, but are both eye-safe and invisible to marine life. Considering the challenge of detecting and evaluating the presence of marine wildlife, we present a full processing pipeline for LiDAR data, that includes water turbidity detection, non-gated backscattering compensation, contrast enhancement, and the construction of a three-dimensional model of the detected target. The pipeline is applied to a number of tank test data, under different turbidity conditions.TRUEpu
Formalizing and Implementing Distributed Ledger Objects
Get PDFPublication Sponsor: SIGACT ACM Special Interest Group on Algorithms and Computation TheoryDespite the hype about blockchains and distributed ledgers, formal abstractions of these objects are scarce. To face this issue, in this paper we provide a proper formulation of a distributed ledger object. In brief, we define a ledger
object as a sequence of records, and we provide the operations and the properties that such an object should support. Implementation of a ledger object on top of multiple (possibly geographically dispersed) computing devices gives rise to the distributed ledger object. In
contrast to the centralized object, distribution allows operations to be applied concurrently on the ledger,
introducing challenges on the consistency of the ledger in each participant. We provide the definitions of three well known consistency guarantees in terms of the operations supported by the ledger object:(1)atomic consistency (linearizability), (2) sequential consistency, and (3)
eventual consistency. We then provide implementations of distributed ledgers on asynchronous message passing crash-prone systems using an Atomic Broadcast service, and show that they provide eventual, sequential or atomic consis-
tency semantics respectively. We conclude with a variation of the ledger – the validated ledger – which requires that each record in the ledger satisfies a particular validation rule.pu