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

Low-Power Wide-Area Networks: A Broad Overview of its Different Aspects

Low-power wide-area networks (LPWANs) are gaining popularity in the research community due to their low power consumption, low cost, and wide geographical coverage. LPWAN technologies complement and outperform short-range and traditional cellular wireless technologies in a variety of applications, including smart city development, machine-to-machine (M2M) communications, healthcare, intelligent transportation, industrial applications, climate-smart agriculture, and asset tracking. This review paper discusses the design objectives and the methodologies used by LPWAN to provide extensive coverage for low-power devices. We also explore how the presented LPWAN architecture employs various topologies such as star and mesh. We examine many current and emerging LPWAN technologies, as well as their system architectures and standards, and evaluate their ability to meet each design objective. In addition, the possible coexistence of LPWAN with other technologies, combining the best attributes to provide an optimum solution is also explored and reported in the current overview. Following that, a comparison of various LPWAN technologies is performed and their market opportunities are also investigated. Furthermore, an analysis of various LPWAN use cases is performed, highlighting their benefits and drawbacks. This aids in the selection of the best LPWAN technology for various applications. Before concluding the work, the open research issues, and challenges in designing LPWAN are presented.publishedVersio

同時送信型無線ネットワークの物理層に関する研究

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 森川 博之, 東京大学教授 相田 仁, 東京大学教授 廣瀬 明, 東京大学准教授 中山 雅哉, 東京大学准教授 落合 秀也University of Tokyo(東京大学

Simulations of the MAC Layer in the LoRaWAN Networks, Journal of Telecommunications and Information Technology, 2020, nr 2

The Internet of Things is changing the approach to data transmission, protocol design and network services. The challenge faced by designers of IoT solutions is to determine the scalability of a given technology, with a particular emphasis placed on unlicensed frequency bandwidth (ISM) transmission in highly urbanized areas. Because the design and implementation of a wireless network for the Internet of Things, relying on each of the presented technologies, is expensive and time consuming, it must be preceded by a performance assessment based on computer simulations. The literature contains various approaches to modeling the mechanisms of the MAC layer of LoRa technology and to its implementation in LoRaWAN networks. The article provides an overview of major LoRa MAC network simulators. It presents and comments on the most important research results obtained by the authors of the aforementioned softwar

Hybrid Chirp Signal Design for Improved Long-Range (LoRa) Communications

Long-range (LoRa) communication has attracted much attention recently due to its utility for many Internet of Things applications. However, one of the key problems of LoRa technology is that it is vulnerable to noise/interference due to the use of only up-chirp signals during modulation. In this paper, to solve this problem, unlike the conventional LoRa modulation scheme, we propose a modulation scheme for LoRa communication based on joint up- and down-chirps. A fast Fourier transform (FFT)-based demodulation scheme is devised to detect modulated symbols. To further improve the demodulation performance, a hybrid demodulation scheme, comprised of FFT- and correlation-based demodulation, is also proposed. The performance of the proposed scheme is evaluated through extensive simulation results. Compared to the conventional LoRa modulation scheme, we show that the proposed scheme exhibits over 3 dB performance gain at a bit error rate of 10−4

Real-Time Sensor Networks and Systems for the Industrial IoT

The Industrial Internet of Things (Industrial IoT—IIoT) has emerged as the core construct behind the various cyber-physical systems constituting a principal dimension of the fourth Industrial Revolution. While initially born as the concept behind specific industrial applications of generic IoT technologies, for the optimization of operational efficiency in automation and control, it quickly enabled the achievement of the total convergence of Operational (OT) and Information Technologies (IT). The IIoT has now surpassed the traditional borders of automation and control functions in the process and manufacturing industry, shifting towards a wider domain of functions and industries, embraced under the dominant global initiatives and architectural frameworks of Industry 4.0 (or Industrie 4.0) in Germany, Industrial Internet in the US, Society 5.0 in Japan, and Made-in-China 2025 in China. As real-time embedded systems are quickly achieving ubiquity in everyday life and in industrial environments, and many processes already depend on real-time cyber-physical systems and embedded sensors, the integration of IoT with cognitive computing and real-time data exchange is essential for real-time analytics and realization of digital twins in smart environments and services under the various frameworks’ provisions. In this context, real-time sensor networks and systems for the Industrial IoT encompass multiple technologies and raise significant design, optimization, integration and exploitation challenges. The ten articles in this Special Issue describe advances in real-time sensor networks and systems that are significant enablers of the Industrial IoT paradigm. In the relevant landscape, the domain of wireless networking technologies is centrally positioned, as expected

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

Machine Learning Aided Orthogonal Resource Allocation In Heterogeneous Low Power Wide Area Networks

　近年，IoTの発展に伴い，長距離通信・超低消費電力・同時多接続などの要件が重要視されている．これらの要求に対応するため，LoRaWAN(Long Range Wide Area Network)に代表されるLPWAN(Low Power Wide Area Network)通信規格に注目が集まっている．これらの規格では，無線ノードの低消費電力化のために各レイヤにおいて単純な機能が用いられている．例えば，MAC層では，集中制御ではなく各無線ノードが自律分散的にランダムアクセスを行うことで周波数リソースの共用を行う多元接続方式が採用されている．このような単純な通信制御では，無線ノード数の増加に伴いパケット衝突が頻発することが大きな問題である．この問題の解決策としては，無線資源を有効に活用できるようなリソース割り当てが挙げられる．しかしながら，LoRaWAN環境においては，拡散係数 (SF: Spreading Factor)と呼ばれる物理層変調パラメータの割り当てしか行われておらず，システムで利用可能な複数の周波数リソースに関しては，各端末がパケット送信時にランダムに周波数を移動するランダムホッピングが適用されている．更に，既存研究は明示的なフィードバックやチャネル推定に基づくものが大半であり，これらの方式はリソース割り当てのために余剰なオーバーヘッドを必要とする．また，920[MHz]帯での利用を想定した場合には，一つの帯域を特定のシステムが専有することは現実的ではなく，複数のシステムが周波数を共用することになる．例えば，使用帯域が重なるLoRaWANシステムとWi-SUNシステム間での相互干渉の影響が挙げられる．このように，実際には他システムの影響を考慮したリソース割り当てが重要である．　本論文では，衝突機能回避付きキャリアセンス多元接続(CSMA/CA: Carrier Sense Multiple Access/Collision Avoidance)をMAC層の多元接続方式として用いるLoRaWAN環境において，強化学習に基づく効率的な周波数リソース割り当て方式を提案する．本提案方式では，各LoRaWANノードから正しく受信できたパケット数という，LoRaWANの情報集約局(FC: Fusion Center)で観測できる情報のみを用いて強化学習を行うことで，LoRaWANノードからの明示的なフィードバックやチャネル推定などの処理を必要とせずに効率的な周波数リソースの割り当てを行うことが可能である．また，これに加えて，密度比推定に基づく分布変化検知を利用した外部からのシステム間干渉の変動に追従できるような干渉検知方式および無線リソース再割当て方式を提案する．計算機シミュレーションにより，提案手法は従来の手法と比較して平均で13%程度パケット配信率(PDR: Packet Delivery Rate)を向上でき，さらに最大で3回程度の観測で外部干渉の状態変化を検知でき，干渉検知を行わない場合と比較して最大で平均10%程度PDRを向上できることを示す．電気通信大学201