Intra-network interference robustness : an empirical evaluation of IEEE 802.15.4-2015 SUN-OFDM

While IEEE 802.15.4 and its Time Slotted Channel Hopping (TSCH) medium access mode were developed as a wireless substitute for reliable process monitoring in industrial environments, most deployments use a single/static physical layer (PHY) configuration. Instead of limiting all links to the throughput and reliability of a single Modulation and Coding Scheme (MCS), you can dynamically re-configure the PHY of link endpoints according to the context. However, such modulation diversity causes links to coincide in time/frequency space, resulting in poor reliability if left unchecked. Nonetheless, to some level, intentional spatial overlap improves resource efficiency while partially preserving the benefits of modulation diversity. Hence, we measured the mutual interference robustness of certain Smart Utility Network (SUN) Orthogonal Frequency Division Multiplexing (OFDM) configurations, as a first step towards combining spatial re-use and modulation diversity. This paper discusses the packet reception performance of those PHY configurations in terms of Signal to Interference Ratio (SIR) and time-overlap percentage between interference and targeted parts of useful transmissions. In summary, we found SUN-OFDM O3 MCS1 and O4 MCS2 performed best. Consequently, one should consider them when developing TSCH scheduling mechanisms in the search for resource efficient ubiquitous connectivity through modulation diversity and spatial re-use

Survey on wireless technology trade-offs for the industrial internet of things

Aside from vast deployment cost reduction, Industrial Wireless Sensor and Actuator Networks (IWSAN) introduce a new level of industrial connectivity. Wireless connection of sensors and actuators in industrial environments not only enables wireless monitoring and actuation, it also enables coordination of production stages, connecting mobile robots and autonomous transport vehicles, as well as localization and tracking of assets. All these opportunities already inspired the development of many wireless technologies in an effort to fully enable Industry 4.0. However, different technologies significantly differ in performance and capabilities, none being capable of supporting all industrial use cases. When designing a network solution, one must be aware of the capabilities and the trade-offs that prospective technologies have. This paper evaluates the technologies potentially suitable for IWSAN solutions covering an entire industrial site with limited infrastructure cost and discusses their trade-offs in an effort to provide information for choosing the most suitable technology for the use case of interest. The comparative discussion presented in this paper aims to enable engineers to choose the most suitable wireless technology for their specific IWSAN deployment

Comparação experimental do desempenho de tecnologias emergentes de low power wide area networks para IoT

Orientadores: Gustavo Fraidenraich, Eduardo Rodrigues de LimaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Esta dissertação apresenta resultados experimentais para a avaliação de dois circuitos integrados para conectividade IoT, usando uma abordagem sistemática. Um dos circuitos é dedicado a LoRa, enquanto o outro utiliza o padrão IEEE 802.15.4g adotado pela Wi-SUN Alliance. O objetivo desta avaliação é apresentar resultados que possam ajudar todos que pretendem utilizar LoRa, IEEE 802.15.4g/Wi-SUN ou outras opções de conectividade, facilitando a comparação entre essas tecnologias de forma justa e coerente. Os resultados mostram que existem diferenças entre os valores apresentados nos datasheet e os valores medidos durante os experimentos. Existem várias razões que justificam essas divergências, como a configuração dos experimentos, calibração dos equipamentos, o tamanho dos pacotes transmitidos e até as especificações dos testes. Esse resultado reforça a importância de uma abordagem sistemática para a comparação entre tecnologiasAbstract: This dissertation presents experimental results on the evaluation of two commercial integrated circuits for IoT connectivity, using a systematic approach. One of the integrated circuits is devoted to LoRa and the other to IEEE 802.15.4g, which is the physical layer adopted by the WI-SUN Alliance. The goal behind this evaluation is to present results to support those who will make use of LoRa, IEEE802.15.4g/Wi-SUN, or other types of connectivity to fairly compare the technologies. The results show that there are differences between datasheet values and the measures collected during the experiments. There are several reasons for this divergence, such as the experimental setup, equipment calibration, transmitted packet length, and test specifications. This highlights the importance of a systematical approach when comparing technologiesMestradoTelecomunicações e TelemáticaMestre em Engenharia Elétric

Smart city street lighting system: An engineering internship at Eco-FX LED

This final year honours thesis project was undertaken with Eco-FX; it involved consulting, designing and developing their new Smart City Street Lighting System. Smart Street Lighting utilises wireless control and monitoring to produce a more energy efficient and sustainable street light system. Previously, the technology and the wider community were obstacles in its development; presently with advancement in wireless low data rate protocols and support from the Western Australian Local Government Association, the development of the system is approaching its completion. To consult on the design and development for this project required vast amounts of research about the existing lighting technologies, public utilities and low data rate wireless protocols. The methodology was to research and evaluate all protocol and hardware technologies available. These technology options were presented to the relevant stakeholders for discussion; and then the final design specification was approved. The ZigBee protocol met final design specifications and requirements for Eco-FX; therefore the ZigBee Alliance was contacted to find the best approach in designing to their standard. After the guidance from the ZigBee Alliance, more research was conducted on the hardware and the services required for implementing the Smart City Street Light System. The final stage in the project was finding manufacturers and designers for the required hardware and software to develop the system in China. The previous research and evaluation provided guidance in specifying to the manufacturer and designer all the critical features required by Eco-FX in the system; and ensured all Australian and international standards were met in the manufacturing and designing process

Modélisation et simulation de réseaux locaux et personnels sans fil : intégration des couches PHY et MAC

Dans ce travail nous nous intéressons à la modélisation des couches MAC et PHY dans le cadre des réseaux sans fil à faible, portée. Il présente les techniques de modélisation utilisées pour l'intégration des couches MAC-PHYs (Medium Access Control and Physical layer) de type IR-UWB (Impulse Radio Ultra Wideband) d'une part, et des nouvelles techniques de transmission à 60GHz incluant le beamforming d'autre part, dans le simulateur GloMoSim/QualNet. La modélisation de IR-UWB est basée sur la prise en compte directe des collisions d'impulsions et de l'interférence multi-utilisateur au niveau de la couche PHY par l'introduction du concept de séquences de réception et la notion d'orthogonalité en réception. L'architecture de modélisation proposée est basée sur l'utilisation d'une matrice d'interférence, elle a été développée en deux étapes : une première modélisation basée sur des trains d'impulsions uniformément espacées et une deuxième modélisation plus complète prenant en compte l'utilisation des séquences de sauts aléatoires également appelés séquences de time hopping. L'évaluation de performances de cette partie est basée sur une application typique des réseaux de capteurs dans le cadre d'une application de détection d'intrusion sur une surface protégée. La modélisation à 60 GHz à pour but la prise en compte des nouvelles techniques d'amélioration du débit, notamment l'agrégation et le beamforming. La prise en compte du beamforming est basée sur la définition, des diagrammes de rayonnement des antennes ainsi que de l'interface MAC-PHY/Antenne. La modélisation des deux protocoles de beamforming définis dans le standard 802.15.3c est également effectuée. L'évaluation de performances de cette partie est basée sur un système de distribution de contenu multimédia.In this work, we focus on physical and medium access control layer modeling and simulation for short range wireless communication. In particular, the modeling of the Impulse Radio Ultra Wide Band technique for wireless sensor networks and the high data rate communication modeling which uses millimeter wave and beamforming. The first part deals with the modeling of Impulse Radio Ultra Wide Band. The proposed model takes into account the pulse collision induced by multiple concurrent transmissions at the physical layer which is also called multi user interference. This aspect is accurately introduced thanks to the concept of reception time hopping sequences of concurrent reception and their orthogonality. The simulation architecture is built using two models: the first model is based on a uniformly distributed pulse train and the second model, more complete, takes into account variable time hopping sequences. The performance evaluation of this part is based on a typical wireless sensor networks application, in which sensor nodes are scattered on a particular area to detect and report intrusion events to a base station. The second part deals with the modeling of high data rate communication using millimeter wave. The targeted goal of millimeter wave transmission is to increase the data rate using some novel techniques: beamforming and data aggregation. Beamforming is modeled on the so-called codebook beamforming defined as the new beamforming technique for high data rate wireless communication standards. A methodology is developed to take into account the radiation pattern defined by the codebook indexes. For each index the gain of the directional antenna is computed for each direction. This is used in the simulation model physical layer to determine the directional antenna gain in a particular direction during the propagation stage. The defined protocols for sector level and beam level training defined in the 802.15.3c draft are also modeled. The performance evaluation of this part is based on a multimedia distribution system

RF-Transformer: A Unified Backscatter Radio Hardware Abstraction

This paper presents RF-Transformer, a unified backscatter radio hardware abstraction that allows a low-power IoT device to directly communicate with heterogeneous wireless receivers at the minimum power consumption. Unlike existing backscatter systems that are tailored to a specific wireless communication protocol, RF-Transformer provides a programmable interface to the micro-controller, allowing IoT devices to synthesize different types of protocol-compliant backscatter signals sharing radically different PHY-layer designs. To show the efficacy of our design, we implement a PCB prototype of RF-Transformer on 2.4 GHz ISM band and showcase its capability on generating standard ZigBee, Bluetooth, LoRa, and Wi-Fi 802.11b/g/n/ac packets. Our extensive field studies show that RF-Transformer achieves 23.8 Mbps, 247.1 Kbps, 986.5 Kbps, and 27.3 Kbps throughput when generating standard Wi-Fi, ZigBee, Bluetooth, and LoRa signals while consuming 7.6-74.2 less power than their active counterparts. Our ASIC simulation based on the 65-nm CMOS process shows that the power gain of RF-Transformer can further grow to 92-678. We further integrate RF-Transformer with pressure sensors and present a case study on detecting foot traffic density in hallways. Our 7-day case studies demonstrate RFTransformer can reliably transmit sensor data to a commodity gateway by synthesizing LoRa packets on top of Wi-Fi signals. Our experimental results also verify the compatibility of RF-Transformer with commodity receivers. Code and hardware schematics can be found at: https://github.com/LeFsCC/RF-Transformer

Metodologia de sensoriamento e acesso dinâmico aos canais em redes de sensores sem fio

A melhora na eficiência do uso do espectro de radiofrequência é fundamental para permitir um desempenho adequado dos diversos sistemas sem fio cuja complexidade e requerimentos aumentam a cada dia. O panorama atual de atribuição de canais é estático, tolerando assim, que o espectro de radiofrequência seja usado de forma desequilibrada, gerando com isso, problemas de coexistência em algumas faixas e subutilização de recursos em outras. Para contornar esse problema, tem sido proposta a ideia de introduzir algoritmos de cognição nos dispositivos sem fio, a fim de permitir um modelo de alocação dinâmico adicional. Neste, os usuários secundários equipados com rádios cognitivos podem utilizar de forma dinâmica os canais subutilizados de usuários primários. Um usuário primário tem prioridade de uso do canal como consequência da atribuição estática, porém, o uso do canal por um usuário secundário qualquer é oportunista e limitando ao tempo de inatividade do usuário primário em um determinado local. As redes de sensores sem fio trabalham em uma banda concorrida e são sistemas que podem melhorar seu desempenho utilizando um mecanismo de acesso dinâmico aos canais, possibilitando o aproveitamento dos períodos de inatividade de usuários primários ou aumentando sua capacidade de coexistência na banda de operação atual. Segundo a literatura pesquisada são vários os desafios existentes para conseguir um método distribuído de acesso dinâmico aos canais que considere as restrições de trocas de sinalizações, consumo de energia e complexidade dos dispositivos de uma rede de sensores sem fio. Neste contexto, propõe-se uma metodologia de sensoriamento e acesso dinâmico aos canais para uma rede de sensores sem fio considerando a simplicidade dos dispositivos. Como fatores de inovação, optou-se pela definição de uma política de sensoriamento por clusters que permite realizar uma aprendizagem cooperativa por reforço da situação dos canais de operação. Além disso, a definição de um mecanismo de acesso dinâmico aos canais fundamentado no padrão IEEE 802.15.4 permite comunicação e coordenação distribuída de forma assíncrona. O funcionamento da metodologia proposta é avaliado e comparado usando simulações e experimentos mediante um estudo de caso específico. As comparações são realizadas com métodos de seleção de canal: fixa, cega ou baseada em recompensas por acesso. Os resultados mostram a eficiência no acesso dinâmico aos canais com aumentos na taxa de entrega de mensagens e na capacidade de coexistir com as redes primárias.The efficiency improvement of the use of radiofrequency spectrum is fundamental to allow more complex and more optimal wireless systems. The current channel allocation is static. It tolerates unbalanced use of the radiofrequency spectrum generating coexistence problems in some bands and underutilization of resources in other bands. The introduction of cognitive algorithms into wireless devices has been proposed to overcome that problem, in order to allow an additional dynamic allocation model. In this, the secondary users equipped with cognitive radios will be able to use dynamically the underutilized channels of primary users. A primary user has channel usage priority related to the static allocation, on the other hand, the use of the channel by any secondary user is opportunistic and limited to the inactivity time of the primary user in a specific place. Wireless sensor networks work in a competitive band. These systems can improve their performance using a dynamic access to the channels and consequently to enable the utilization of inactivity periods of primary users or to increase the coexistence capability at their current operation band. According to the researched literature, several challenges exist to find a distributed method for dynamic access to the channels considering the restrictions on control signaling, energy consumption and computational complexity of wireless sensor network devices. In this context, a methodology of sensing and dynamic access to the channels in a wireless sensor network considering the restrictions of the devices is proposed. As innovation, we opted for the definition of a sensing policy by clusters that allows the cooperative reinforcement learning of the situation of channels. In addition, a mechanism for dynamic access to the channels based on the IEEE 802.15.4 standard is defined to allow asynchronous and distributed coordination. The behavior of the proposed methodology is evaluated and compared using simulations and experiments through a specific case study. The comparisons are performed with channel selection methods: fixed, blind and access based. The results show good efficiency in the dynamic allocation of the channels, increasing the message delivery rate and the coexistence capability