Experimental Interference Robustness Evaluation of IEEE 802.15.4-2015 OQPSK-DSSS and SUN-OFDM Physical Layers for Industrial Communications

International audienceIn this paper, we experimentally evaluate and compare the robustness against interference of the OQPSK-DSSS (Offset Quadrature Phase Shift Keying-Direct Sequence Spread Spectrum) and the SUN-OFDM (Smart Utility Network-Orthogonal Frequency Division Multiplexing) physical layers, as defined in the IEEE 802.15.4-2015 standard. The objective of this study is to provide a comprehensive analysis of the impact that different levels of interference produce on these modulations, in terms of the resulting PDR (Packet Delivery Ratio) and depending on the length of the packet being transmitted. The results show that the SUN-OFDM physical layer provides significant benefits compared to the ubiquitous OQPSK-DSSS in terms of interference robustness, regardless of the interference type and the packet length. Overall, this demonstrates the suitability of choosing the SUN-OFDM physical layer when deploying low-power wireless networks in industrial scenarios, especially taking into consideration the possibility of trading-off robustness and spectrum efficiency depending on the application requirements

No Free Lunch - Characterizing the Performance of 6TiSCH When Using Different Physical Layers

International audienceLow-power wireless applications require different trade off points between latency, reliability ,data rate and power consumption. Given such a set of constraints, which physical layer should I beusing? We study this question in the context of 6TiSCH,a state-of-the-art recently standardized protocol stack developed for harsh industrial applications. Specifically,we augment OpenWSN, the reference 6TiSCHopen-source implementation,to support one of three physical layers from the IEEE802.15.4g standard FSK 868 MHz which offers long range, OFDM 868 MHz which offers high data rate,and O-QPSK 2.4GHz which offers more balanced performance. We run the resulting firmware on the42-mote Open Testbed deployed in an office environment, once for each physical layer. Performance results show that, indeed, no physical layer outperforms the other for all metrics. This article argues for combining the physical layers, rather than choosing one,in a generalized 6TiSCH architecture in which technology-agile radio chips (of which there are now many) are driven by a protocol stack which c hooses the most appropriate physical layer on a frame-by-frame basis

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

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

Experimental Interference Robustness Evaluation of IEEE 802.15.4-2015 OQPSK-DSSS and SUN-OFDM Physical Layers for Industrial Communications

In this paper, we experimentally evaluate and compare the robustness against interference of the OQPSK-DSSS (Offset Quadrature Phase Shift Keying-Direct Sequence Spread Spectrum) and the SUN-OFDM (Smart Utility Network-Orthogonal Frequency Division Multiplexing) physical layers, as defined in the IEEE 802.15.4-2015 standard. The objective of this study is to provide a comprehensive analysis of the impact that different levels of interference produce on these modulations, in terms of the resulting PDR (Packet Delivery Ratio) and depending on the length of the packet being transmitted. The results show that the SUN-OFDM physical layer provides significant benefits compared to the ubiquitous OQPSK-DSSS in terms of interference robustness, regardless of the interference type and the packet length. Overall, this demonstrates the suitability of choosing the SUN-OFDM physical layer when deploying low-power wireless networks in industrial scenarios, especially taking into consideration the possibility of trading-off robustness and spectrum efficiency depending on the application requirements

Experimental Interference Robustness Evaluation of IEEE 802.15.4-2015 OQPSK-DSSS and SUN-OFDM Physical Layers for Industrial Communications

International audienceIn this paper, we experimentally evaluate and compare the robustness against interference of the OQPSK-DSSS (Offset Quadrature Phase Shift Keying-Direct Sequence Spread Spectrum) and the SUN-OFDM (Smart Utility Network-Orthogonal Frequency Division Multiplexing) physical layers, as defined in the IEEE 802.15.4-2015 standard. The objective of this study is to provide a comprehensive analysis of the impact that different levels of interference produce on these modulations, in terms of the resulting PDR (Packet Delivery Ratio) and depending on the length of the packet being transmitted. The results show that the SUN-OFDM physical layer provides significant benefits compared to the ubiquitous OQPSK-DSSS in terms of interference robustness, regardless of the interference type and the packet length. Overall, this demonstrates the suitability of choosing the SUN-OFDM physical layer when deploying low-power wireless networks in industrial scenarios, especially taking into consideration the possibility of trading-off robustness and spectrum efficiency depending on the application requirements

Experimental interference robustness evaluation of IEEE 802.15.4-2015 OQPSK-DSSS and SUN-OFDM physical layers for industrial communications

In this paper, we experimentally evaluate and compare the robustness against interference of the OQPSK-DSSS (Offset Quadrature Phase Shift Keying-Direct Sequence Spread Spectrum) and the SUN-OFDM (Smart Utility Network-Orthogonal Frequency Division Multiplexing) physical layers, as defined in the IEEE 802.15.4-2015 standard. The objective of this study is to provide a comprehensive analysis of the impact that different levels of interference produce on these modulations, in terms of the resulting PDR (Packet Delivery Ratio) and depending on the length of the packet being transmitted. The results show that the SUN-OFDM physical layer provides significant benefits compared to the ubiquitous OQPSK-DSSS in terms of interference robustness, regardless of the interference type and the packet length. Overall, this demonstrates the suitability of choosing the SUN-OFDM physical layer when deploying low-power wireless networks in industrial scenarios, especially taking into consideration the possibility of trading-off robustness and spectrum efficiency depending on the application requirements

Estudio de la fiabilidad de capas físicas inalámbricas de 2.45 GHZ en entornos industriales mediante emulación de canal.

141 p.Las comunicaciones inalámbricas ocupan un papel fundamental dentro de la Industria 4.0. Sin embargo, su uso en entornos industriales, aunque cada vez más presente, sigue siendo residual si se compara con las comunicaciones cableadas. Esto se debe a que las propiedades físicas del entorno industrial generan unas condiciones de propagación que distan mucho de ser ideales, afectando negativamente a la fiabilidad de las comunicaciones.Cuando se desea desplegar un enlace inalámbrico en un entorno industrial, es necesario realizar una validación de la fiabilidad de las comunicaciones que de ciertas garantías de funcionamiento. Las metodologías actuales presentan deficiencias cuando son aplicadas en entornos industriales, las cuales se traducen en una la falta de reproducibilidad y una la falta de exactitud de los resultados de las validaciones respecto a los obtenidos posteriormente tras el despliegue.Por ello, en esta tesis se define una metodología para evaluar y validar la fiabilidad de las capas físicas de sistemas de comunicaciones inalámbricos empleados por nodos terminales en casos de uso industriales. Esta metodología considera las métricas adecuadas para evaluar la fiabilidad, los parámetros necesarios para definir correctamente el escenario de medida, los detalles del setup de laboratorio y el algoritmo de comunicación a emplear.Así mismo, se aplica la metodología propuesta para evaluar y validar la fiabilidad de tres capas físicas definidas por los estándares inalámbricos IEEE 802.15.4 y Bluetooth Low Energy. Ello ha permitido obtener resultados de fiabilidad de todas las capas físicas tanto para canales de propósito general como para canales puramente industriales. También se han obtenido expresiones matemáticas para predecir la fiabilidad de las capas físicas bajo los diferentes canales industriales. Por último, se han validado dichas capas físicas para tres casos de uso industrial generales