20 research outputs found
Quantum Switches for Gottesman-Kitaev-Preskill Qubit-based All-Photonic Quantum Networks
The Gottesman-Kitaev-Preskill (GKP) code, being information theoretically
near optimal for quantum communication over Gaussian thermal-loss optical
channels, is likely to be the encoding of choice for advanced quantum networks
of the future. Quantum repeaters based on GKP-encoded light have been shown to
support high end-to-end entanglement rates across large distances despite
realistic finite squeezing in GKP code preparation and homodyne detection
inefficiencies. Here, we introduce a quantum switch for GKP-qubit-based quantum
networks, whose architecture involves multiplexed GKP-qubit-based entanglement
link generation with clients, and their all-photonic storage, together enabled
by GKP-qubit graph state resources. For bipartite entanglement distribution
between clients via entanglement swapping, the switch uses a multi-client
generalization of a recently introduced protocol heuristic. Since generating the GKP-qubit graph state
resource is hardware intensive, given a total resource budget and an arbitrary
layout of clients, we address the question of their optimal allocation towards
the different client-pair connections served by the switch such that the sum
throughput of the switch is maximized while also being fair in terms of the
individual entanglement rates. We illustrate our results for an exemplary data
center network, where the data center is a client of a switch and all of its
other clients aim to connect to the data center alone -- a scenario that also
captures the general case of a gateway router connecting a local area network
to a global network. Together with compatible quantum repeaters, our quantum
switch provides a way to realize quantum networks of arbitrary topology.Comment: 13 pages, 8 Figure
NFV Based Gateways for Virtualized Wireless Sensors Networks: A Case Study
Virtualization enables the sharing of a same wireless sensor network (WSN) by
multiple applications. However, in heterogeneous environments, virtualized
wireless sensor networks (VWSN) raises new challenges such as the need for
on-the-fly, dynamic, elastic and scalable provisioning of gateways. Network
Functions Virtualization (NFV) is an emerging paradigm that can certainly aid
in tackling these new challenges. It leverages standard virtualization
technology to consolidate special-purpose network elements on top of commodity
hardware. This article presents a case study on NFV based gateways for VWSNs.
In the study, a VWSN gateway provider, operates and manages an NFV based
infrastructure. We use two different brands of wireless sensors. The NFV
infrastructure makes possible the dynamic, elastic and scalable deployment of
gateway modules in this heterogeneous VWSN environment. The prototype built
with Openstack as platform is described
All-photonic multiplexed quantum repeaters based on concatenated bosonic and discrete-variable quantum codes
Long distance quantum communication will require the use of quantum repeaters
to overcome the exponential attenuation of signal with distance. One class of
such repeaters utilizes quantum error correction to overcome losses in the
communication channel. Here we propose a novel strategy of using the bosonic
Gottesman-Kitaev-Preskill (GKP) code in a two-way repeater architecture with
multiplexing. The crucial feature of the GKP code that we make use of is the
fact that GKP qubits easily admit deterministic two-qubit gates, hence allowing
for multiplexing without the need for generating large cluster states as
required in previous all-photonic architectures based on discrete-variable
codes. Moreover, alleviating the need for such clique-clusters entails that we
are no longer limited to extraction of at most one end-to-end entangled pair
from a single protocol run. In fact, thanks to the availability of the analog
information generated during the measurements of the GKP qubits, we can design
better entanglement swapping procedures in which we connect links based on
their estimated quality. This enables us to use all the multiplexed links so
that large number of links from a single protocol run can contribute to the
generation of the end-to-end entanglement. We find that our architecture allows
for high-rate end-to-end entanglement generation and is resilient to
imperfections arising from finite squeezing in the GKP state preparation and
homodyne detection inefficiency. In particular we show that long-distance
quantum communication over more than 1000 km is possible even with less than 13
dB of GKP squeezing. We also quantify the number of GKP qubits needed for the
implementation of our scheme and find that for good hardware parameters our
scheme requires around GKP qubits per repeater per protocol run.Comment: 31 + 25 pages, 40 figure
Wireless sensor network virtualization: Early architecture and research perspectives
© 2015 IEEE. WSNs have become pervasive and are used in many applications and services. Usually, deployments of WSNs are task-oriented and domain-specific, thereby precluding reuse when other applications and services are contemplated. This inevitably leads to the proliferation of redundant WSN deployments. Virtualization is a technology that can aid in tackling this issue, as it enables the sharing of resources/infrastructure by multiple independent entities. In this article we critically review the state of the art and propose a novel architecture for WSN virtualization. The proposed architecture has four layers (physical layer, virtual sensor layer, virtual sensor access layer, and overlay layer) and relies on a constrained application protocol. We illustrate its potential by using it in a scenario where a single WSN is shared by multiple applications, one of which is a fire monitoring application. We present the proof-of-concept prototype we have built along with the performance measurements, and discuss future research directions
IoT end-user applications provisioning in the cloud: State of the art
© 2016 IEEE. Internet of Things (IoT) is expected to enable a myriad of end-user applications by interconnecting physical objects. Cloud computing is a promising paradigm for provisioning IoT end-user applications in a cost-efficient manner. IoT end-user applications are provisioned in cloud settings using PaaS and offered as SaaS. This paper focuses on the PaaS aspects of IoT end-user applications provisioning. It critically reviews the state of the art. The critical review discusses the PaaS on the whole spectrum of IoT verticals and also the PaaS dealing with specific IoT verticals
A comprehensive survey on Fog Computing: State-of-the-art and research challenges
Cloud computing with its three key facets (i.e.,
Infrastructure-as-a-Service, Platform-as-a-Service, and Softwareas-
a-Service) and its inherent advantages (e.g., elasticity and
scalability) still faces several challenges. The distance between
the cloud and the end devices might be an issue for latencysensitive
applications such as disaster management and content
delivery applications. Service level agreements (SLAs) may also
impose processing at locations where the cloud provider does not
have data centers. Fog computing is a novel paradigm to address
such issues. It enables provisioning resources and services outside
the cloud, at the edge of the network, closer to end devices, or
eventually, at locations stipulated by SLAs. Fog computing is not
a substitute for cloud computing but a powerful complement. It
enables processing at the edge while still offering the possibility
to interact with the cloud. This paper presents a comprehensive
survey on fog computing. It critically reviews the state of
the art in the light of a concise set of evaluation criteria. We
cover both the architectures and the algorithms that make fog
systems. Challenges and research directions are also introduced.
In addition, the lessons learned are reviewed and the prospects
are discussed in terms of the key role fog is likely to play in
emerging technologies such as tactile Internet
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POSITIVE AND NEGATIVE PION-PROTON BACKWARD ELASTIC SCATTERING BETWEEN 30 AND 90 GEV/C.
Measurements of the differential cross sections for backward (pi)('+)p and (pi)('-)p elastic scattering have been made for incident pion momenta between 30 and 90 GeV/c in the angular range 0 ) p(pi)('-), the (DELTA)(,(delta)) and N(,(alpha)) for (pi)('+)p (--->) p(pi)('+). As is given by this model, the momentum dependence of the differential cross-section, d(sigma)/du for fixed u, may be parameterized with the form (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI) The values n('+) = 2.31 (+OR-) 0.07 and n('-) = 2.08 (+OR-) 0.06 are obtained for n at u = 0 for (pi)('+) and (pi)('-) scattering respectively
Self-Optimization of LTE Networks Utilizing Celnet Xplorer
In order to meet demanding performance objectives in Long Term Evolution (LTE) networks, it is mandatory to implement highly efficient, autonomic self-optimization and configuration processes. Self-optimization processes have already been studied in second generation (2G) and third generation (3G) networks, typically with the objective of improving radio coverage and channel capacity. The 3rd Generation Partnership Project (3GPP) standard for LTE self-organization of networks (SON) provides guidelines on self-configuration of physical cell ID and neighbor relation function and self-optimization for mobility robustness, load balancing, and inter-cell interference reduction. While these are very important from an optimization perspective of local phenomenon (i.e., the eNodeB's interaction with its neighbors), it is also essential to architect control algorithms to optimize the network as a whole. In this paper, we propose a Celnet Xplorer-based SON architecture that allows detailed analysis of network performance combined with a SON control engine to optimize the LTE network. The network performance data is obtained in two stages. In the first stage, data is acquired through intelligent non-intrusive monitoring of the standard interfaces of the Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) and Evolved Packet Core (EPC), coupled with reports from a software client running in the eNodeBs. In the second stage, powerful data analysis is performed on this data, which is then utilized as input for the SON engine. Use cases involving tracking area optimization, dynamic bearer profile reconfiguration, and tuning of network-wide coverage and capacity parameters are presented. (C) 2010 Alcatel-Lucent
Secure base stations
With the introduction of the third generation (3G) Universal Mobile Telecommunications System (UMTS) base station router (BSR) and fourth generation (4G) base stations, such as the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) Evolved Node B (eNB), it has become important to secure base stations from break-in attempts by adversaries. While previous generation base stations could be considered simple voice and Internet Protocol (IP) packet transceivers, newer generation cellular base stations need to perform more of the user- and signaling functions for the cellular radio access network. If adversaries can physically break into newer base stations, they can perform a range of undesirable operations such as snooping on conversations, carrying out denial-of-service attacks on the serving area, changing the software base of the base stations, stealing authentication and encryption keys, and disrupting legitimate cellular operations. The cell-site vault is a secure processing environment designed to resist such tampering and to protect the sensitive functions associated with cellular processing. It provides an execution environment where ciphering functions, key management, and associated functions can execute without leaking sensitive information. In this paper, we present the basic principles of the cell-site vault and present an overview of the types of functions that need to be protected in future base stations for cellular networks. We address the importance of providing a trust hierarchy within the cell-site vault, we present why the vault needs to be used to establish secure and authenticated communication channelsâin fact, why the vault needs to be used for most external communicationsâand we present why it is important to execute functions such as data re-encryption inside the vault. A femtocell or home base station is particularly vulnerable to attacks since these base stations are physically accessible by adversaries. In this paper, we focus in particular on a cell-site vault design for a femto-class base station, including its standardization efforts, as it is challenging to include both secure and nonsecure processing inside a single âsystem-on-a-chip.