Service Migration from Cloud to Multi-tier Fog Nodes for Multimedia Dissemination with QoE Support.

A wide range of multimedia services is expected to be offered for mobile users via various wireless access networks. Even the integration of Cloud Computing in such networks does not support an adequate Quality of Experience (QoE) in areas with high demands for multimedia contents. Fog computing has been conceptualized to facilitate the deployment of new services that cloud computing cannot provide, particularly those demanding QoE guarantees. These services are provided using fog nodes located at the network edge, which is capable of virtualizing their functions/applications. Service migration from the cloud to fog nodes can be actuated by request patterns and the timing issues. To the best of our knowledge, existing works on fog computing focus on architecture and fog node deployment issues. In this article, we describe the operational impacts and benefits associated with service migration from the cloud to multi-tier fog computing for video distribution with QoE support. Besides that, we perform the evaluation of such service migration of video services. Finally, we present potential research challenges and trends

Channel Encoding Block for Mobile WiMAX Networks Using Reconfigurable Hardware

WiMAX technology aims to provide wireless metropolitan area transmissions with guaranteed quality of service. Towards this aim, sophisticated channel encoding techniques must be implemented in a hardware, which is optimized for such techniques. In this context, this article presents the design of a channel encoder for mobile WiMAX networks, which is prototyped in reconfigurable hardware architecture.The validation of the prototype was conducted considering scheduled traffic in the medium access control layer. Results showed that the channel encoder is fundamental for guaranteeing quality of service in mobile WiMAX networks.Keywords: Channel Encoding Block, Reconfigurable Hardware, WiMAX

Optimal Resource Allocation with Delay Guarantees for Network Slicing in Disaggregated RAN

In this article, we propose a novel formulation for the resource allocation problem of a sliced and disaggregated Radio Access Network (RAN) and its transport network. Our proposal assures an end-to-end delay bound for the Ultra-Reliable and Low-Latency Communication (URLLC) use case while jointly considering the number of admitted users, the transmission rate allocation per slice, the functional split of RAN nodes and the routing paths in the transport network. We use deterministic network calculus theory to calculate delay along the transport network connecting disaggregated RANs deploying network functions at the Radio Unit (RU), Distributed Unit (DU), and Central Unit (CU) nodes. The maximum end-to-end delay is a constraint in the optimization-based formulation that aims to maximize Mobile Network Operator (MNO) profit, considering a cash flow analysis to model revenue and operational costs using data from one of the world's leading MNOs. The optimization model leverages a Flexible Functional Split (FFS) approach to provide a new degree of freedom to the resource allocation strategy. Simulation results reveal that, due to its non-linear nature, there is no trivial solution to the proposed optimization problem formulation. Our proposal guarantees a maximum delay for URLLC services while satisfying minimal bandwidth requirements for enhanced Mobile BroadBand (eMBB) services and maximizing the MNO's profit.Comment: 21 pages, 10 figures. For the associated GitHub repository, see https://github.com/LABORA-INF-UFG/paper-FGKCJ-202

A Survey on Long-Range Wide-Area Network Technology Optimizations

Long-Range Wide-Area Network (LoRaWAN) enables flexible long-range service communications with low power consumption which is suitable for many IoT applications. The densification of LoRaWAN, which is needed to meet a wide range of IoT networking requirements, poses further challenges. For instance, the deployment of gateways and IoT devices are widely deployed in urban areas, which leads to interference caused by concurrent transmissions on the same channel. In this context, it is crucial to understand aspects such as the coexistence of IoT devices and applications, resource allocation, Media Access Control (MAC) layer, network planning, and mobility support, that directly affect LoRaWAN’s performance.We present a systematic review of state-of-the-art works for LoRaWAN optimization solutions for IoT networking operations. We focus on five aspects that directly affect the performance of LoRaWAN. These specific aspects are directly associated with the challenges of densification of LoRaWAN. Based on the literature analysis, we present a taxonomy covering five aspects related to LoRaWAN optimizations for efficient IoT networks. Finally, we identify key research challenges and open issues in LoRaWAN optimizations for IoT networking operations that must be further studied in the future

Utilizando o testbed Smart City para treinar alunos de engenharia em tópicos de gerenciamento de rede durante a pandemia de COVID-19

Com as imensas oportunidades para tornar uma rede de comunicação programável, a virtualização de funções de rede e redes definidas por software estão ganhando força tanto na indústria quanto nos círculos de pesquisa, sendo um conjunto de habilidades fundamentais para engenheiros elétricos e cientistas da computação. Portanto, neste artigo, apresentamos e avaliamos a estrutura educacional para o ensino prático de Service Function Chaining (SFC) para alunos de graduação com o objetivo de prepará-los para o futuro mercado de Tecnologias de Informação e Comunicação (TIC) e redes de comunicação que demandará profissionais habilidosos na área. A estrutura educacional foi projetada para o curso de Gerenciamento de Rede da Universidade de Antuérpia, com o objetivo de preencher a lacuna entre os conceitos de programabilidade de rede aplicados na indústria e os ensinados na Universidade. Avaliamos a estrutura educacional com duas extensas pesquisas como feedback dos alunos que nos deram a oportunidade de medir e quantificar a experiência e satisfação dos alunos com a estrutura. Em particular, com base no ambiente desafiador imposto pelo COVID-19, identificamos as lacunas neste quadro educativo e abordar melhorias nas componentes teórica e prática de acordo com as necessidades dos alunos. Nossa estrutura educacional e a avaliação minuciosa servem como uma orientação útil sobre como modernizar os cursos de engenharia e acompanhar o ritmo da tecnologia

Quality of 'Fuji' apples stored under controlled atmosphere and influence of climate on the incidence of internal browning

O objetivo deste trabalho foi avaliar a qualidade de frutos e a relação entre condições climáticas durante o desenvolvimento dos frutos e incidência de degenerescência da polpa no armazenamento em atmosfera controlada (AC) de maçãs 'Fuji'. Foram utilizados frutos de três pomares (Vacaria, RS, e São Joaquim e Lages, SC) e de dois anos agrícolas (2006/2007 e 2007/2008). Durante o desenvolvimento dos frutos, os pomares foram monitorados diariamente, quanto a temperaturas mínimas, médias e máximas, umidade relativa e precipitação. Os frutos foram armazenados por oito meses em diferentes condições de AC, a -0,5±0,1ºC e umidade relativa de 97%. Foram estimadas as correlações de Pearson entre as variáveis relativas às condições climáticas e a incidência de degenerescência da polpa após o armazenamento sob AC. Frutos armazenados sob 1,2 kPa de O2 e 2,0 kPa de CO2 apresentaram maior acidez titulável, firmeza de polpa e textura e menores taxas respiratória e de produção de etileno; exibiram, porém, alta incidência de degenerescência da polpa, em comparação aos armazenados sob 1,2 kPa de O2 e <0,5 kPa de CO2. A incidência de degenerescência da polpa diminui com o aumento nas temperaturas médias diárias, ocorridas entre 90 e 210 dias após o pleno florescimento.The objective of this work was to evaluate fruit quality and the relation between climatic conditions controlled atmosphere (CA) of storage, in Fuji apples. Fruit from three orchards (Vacaria, RS, and São Joaquim and Lages, SC) and two years (2006/2007 e 2007/2008) were evaluated. The orchards were daily monitored, during fruit development, for . Fruit were stored during eight months in different CA conditions, at -0.5±0,1ºC and 97% . Pearson's correlations between climatic condition variables and internal browning incidence after CA storage were estimated. Fruit stored under 1.2 kPa of O2 and 2.0 kPa of CO2 had higher titratable acidity, flesh firmness and texture, and lower respiration and ethylene production rates; however these fruit exhibited a high internal browning incidence in comparison to fruit stored at 1.2 kPa of O2 and <0.5 kPa of CO2. The internal browning incidence decreases as the medium daily temperatures occurred between 90 and 210 days after full bloom increase

Optimizing C-RAN Backhaul Topologies: A Resilience-Oriented Approach Using Graph Invariants

ABSTRACT: At the verge of the launch of the first commercial fifth generation (5G) system, trends in wireless and optical networks are proceeding toward increasingly dense deployments, supporting resilient interconnection for applications that carry higher and higher capacity and tighter latency requirements. These developments put increasing pressure on network backhaul and drive the need for a re-examination of traditional backhaul topologies. Challenges of impending networks cannot be tackled by star and ring approaches due to their lack of intrinsic survivability and resilience properties, respectively. In support of this re-examination, we propose a backhaul topology design method that formulates the topology optimization as a graph optimization problem by capturing both the objective and constraints of optimization in graph invariants. Our graph theoretic approach leverages well studied mathematical techniques to provide a more systematic alternative to traditional approaches to backhaul design. Specifically, herein, we optimize over some known graph invariants, such as maximum node degree, topology diameter, average distance, and edge betweenness, as well as over a new invariant called node Wiener impact, to achieve baseline backhaul topologies that match the needs for resilient future wireless and optical networks

Enhancing Network Slicing Architectures with Machine Learning, Security, Sustainability and Experimental Networks Integration

Network Slicing (NS) is an essential technique extensively used in 5G networks computing strategies, mobile edge computing, mobile cloud computing, and verticals like the Internet of Vehicles and industrial IoT, among others. NS is foreseen as one of the leading enablers for 6G futuristic and highly demanding applications since it allows the optimization and customization of scarce and disputed resources among dynamic, demanding clients with highly distinct application requirements. Various standardization organizations, like 3GPP's proposal for new generation networks and state-of-the-art 5G/6G research projects, are proposing new NS architectures. However, new NS architectures have to deal with an extensive range of requirements that inherently result in having NS architecture proposals typically fulfilling the needs of specific sets of domains with commonalities. The Slicing Future Internet Infrastructures (SFI2) architecture proposal explores the gap resulting from the diversity of NS architectures target domains by proposing a new NS reference architecture with a defined focus on integrating experimental networks and enhancing the NS architecture with Machine Learning (ML) native optimizations, energy-efficient slicing, and slicing-tailored security functionalities. The SFI2 architectural main contribution includes the utilization of the slice-as-a-service paradigm for end-to-end orchestration of resources across multi-domains and multi-technology experimental networks. In addition, the SFI2 reference architecture instantiations will enhance the multi-domain and multi-technology integrated experimental network deployment with native ML optimization, energy-efficient aware slicing, and slicing-tailored security functionalities for the practical domain.Comment: 10 pages, 11 figure