Wireless industrial monitoring and control networks: the journey so far and the road ahead

While traditional wired communication technologies have played a crucial role in industrial monitoring and control networks over the past few decades, they are increasingly proving to be inadequate to meet the highly dynamic and stringent demands of today’s industrial applications, primarily due to the very rigid nature of wired infrastructures. Wireless technology, however, through its increased pervasiveness, has the potential to revolutionize the industry, not only by mitigating the problems faced by wired solutions, but also by introducing a completely new class of applications. While present day wireless technologies made some preliminary inroads in the monitoring domain, they still have severe limitations especially when real-time, reliable distributed control operations are concerned. This article provides the reader with an overview of existing wireless technologies commonly used in the monitoring and control industry. It highlights the pros and cons of each technology and assesses the degree to which each technology is able to meet the stringent demands of industrial monitoring and control networks. Additionally, it summarizes mechanisms proposed by academia, especially serving critical applications by addressing the real-time and reliability requirements of industrial process automation. The article also describes certain key research problems from the physical layer communication for sensor networks and the wireless networking perspective that have yet to be addressed to allow the successful use of wireless technologies in industrial monitoring and control networks

PACKET ERROR RATE PREDICTIVE MODEL FOR SENSOR RADIOS ON FAST ROTATING STRUCTURES

Wireless sensing technologies have raised widespread interests in the applications for monitoring fast rotating or moving machinery structures in manufacturing environments. Over the past five years, a few wireless sensor systems have been implemented and proven to feasibly work under fast rotation conditions. However, few of these studies evaluated data transmission performance of the wireless communication systems. Although the manufacturing environments are known to be harsh for wireless communication, in many cases, an excellent data throughput is critical for such systems. Conventional statistical methods for studying wireless communication channels are not sufficient in this specific field. This dissertation presents systematic experiments to understand and characterize the behavior of a 2.4 GHz band wireless channel between a fast rotating transmitter and a stationary data receiver. The experiments prove, in manufacturing machines, multipath propagation induced by metallic objects causes high power attenuation of radio signals during transmitter motion, and the consequence, low received signal power, is recognized as the major cause of transmission errors. The dissertation proposes a deterministic packet error rate (PER) predictive model for rotating wireless measuring systems using IEEE 802.15.4 sensor radios. The model consists of three sub-models that predict power attenuation, bit error rate (BER), and PER in three stages for given specifications regarding environment, radio transmission, and rotation. The dissertation provides experimental validation of the sub-models and discusses their limitations and prediction errors. By either experiments or simulations, two data transmission protocols, automatic retransmission request (ARQ) method and online error avoidance algorithm, are proved efficient for a reliable wireless communication of such sensor radios. As the first effort to characterize and model such radio channels, the dissertation provides in-depth understandings of the channels\u27 fast varying behavior, achieves prediction guidance for the channels\u27 communication performance, and introduces prospective transmission protocols for performance enhancement

Radio Link Design Framework for WSN Deployment and Performance Prediction

To address the needs of Cyber Physical System applications, and particularly for an easy implementation of wireless sensor and actuator networks (WSAN), semiconductor companies are offering single-chip solutions embedding in the same device a microcontroller core with a wireless transceiver. These internet-on-chip devices support different connections [1-4]: Bluetooth, ZigBee and Bluetooth Low Energy at 2.4 GHz, Wi-Fi at 5 GHz, sub-GHz ISM (Industrial, Scientific, Medical) at 868/915 MHz or 315/433 MHz. The used microcontroller cores range from 8-bit 8051 for low-power short-range solutions to 32-bit Cortex-M ARM ones. The max. sustained bit-rates are from 250 kb/s (sub-GHz links) to 4 Mb/s (Wi-Fi). For example, in case of TI cc254x and cc31xx devices, there are different trade-offs between receiver sensitivity (from -74 dBm to -100 dBm) and maximum transmitter power (from 0 dBm to 5 dBm). These performance parameters lead to different link distances, but also to different power consumption levels, from few mW to several hundreds of mW. A range extender device can be added [5] to improve RX noise figure (down to 4.7 dB) and TX power (up to 22 dBm), although for a power overhead of 480 mW

On-Body Channel Measurement Using Wireless Sensors

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Hybrid Satellite-Terrestrial Communication Networks for the Maritime Internet of Things: Key Technologies, Opportunities, and Challenges

With the rapid development of marine activities, there has been an increasing number of maritime mobile terminals, as well as a growing demand for high-speed and ultra-reliable maritime communications to keep them connected. Traditionally, the maritime Internet of Things (IoT) is enabled by maritime satellites. However, satellites are seriously restricted by their high latency and relatively low data rate. As an alternative, shore & island-based base stations (BSs) can be built to extend the coverage of terrestrial networks using fourth-generation (4G), fifth-generation (5G), and beyond 5G services. Unmanned aerial vehicles can also be exploited to serve as aerial maritime BSs. Despite of all these approaches, there are still open issues for an efficient maritime communication network (MCN). For example, due to the complicated electromagnetic propagation environment, the limited geometrically available BS sites, and rigorous service demands from mission-critical applications, conventional communication and networking theories and methods should be tailored for maritime scenarios. Towards this end, we provide a survey on the demand for maritime communications, the state-of-the-art MCNs, and key technologies for enhancing transmission efficiency, extending network coverage, and provisioning maritime-specific services. Future challenges in developing an environment-aware, service-driven, and integrated satellite-air-ground MCN to be smart enough to utilize external auxiliary information, e.g., sea state and atmosphere conditions, are also discussed

Experimental Investigation Of Ultrawideband Wireless Systems: Waveform Generation, Propagation Estimation, And Dispersion Compensation

Ultrawideband (UWB) is an emerging technology for the future high-speed wireless communication systems. Although this technology offers several unique advantages like robustness to fading, large channel capacity and strong anti-jamming ability, there are a number of practical challenges which are topics of current research. One key challenge is the increased multipath dispersion which results because of the fine temporal resolution. The received response consists of different components, which have certain delays and attenuations due to the paths they took in their propagation from the transmitter to the receiver. Although such challenges have been investigated to some extent, they have not been fully explored in connection with sophisticated transmit beamforming techniques in realistic multipath environments. The work presented here spans three main aspects of UWB systems including waveform generation, propagation estimation, and dispersion compensation. We assess the accuracy of the measured impulse responses extracted from the spread spectrum channel sounding over a frequency band spanning 2-12 GHz. Based on the measured responses, different transmit beamforming techniques are investigated to achieve high-speed data transmission in rich multipath channels. We extend our work to multiple antenna systems and implement the first experimental test-bed to investigate practical challenges such as imperfect channel estimation or coherency between the multiple transmitters over the full UWB band. Finally, we introduce a new microwave photonic arbitrary waveform generation technique to demonstrate the first optical-wireless transmitter system for both characterizing channel dispersion and generating predistorted waveforms to achieve spatio-temporal focusing through the multipath channels