Recent advances in Industrial Internet: insights and challenges

Based on fog computer, an industrial wireless sensor network (F-IWSN) is a novel wireless sensor network in the industry. It not only can more efficiently reduce information transmission latency, but also can more beneficially achieve the real-time control and the rapid resource scheduling. However, similar to other distributed networks, it also faces enormous security challenges, especially those internal attacks. The differences from those traditional security schemes are that, one is the trade-off between security, transmission performance and energy consumption to meet the requirements of information convergence and control, the other constructs a multi-dimensional selective forwarding scheme to achieve the real time transmission. In this paper, we propose a Gaussian distribution-based comprehensive trust management system (GDTMS) for F-IWSN. Furthermore, in its trust decision, the grey decision making is introduced to achieve the trade-off between security, transmission performance and energy consumption. The proposed trade-off can effectively select the secure and robust relay node, namely, a trust management-based secure routing scheme. In addition, the proposed schemes are also applicable to defending against bad mouthing attacks. Simulation results show that, the comprehensive performance of GDTMS is better than other similar algorithms. It can effectively prevent the appearance of network holes, and balance the network load, promote the survivability of the network.

TMSRS: trust management-based secure routing scheme in industrial wireless sensor network with fog computing

Industrial Internet of Things covers all aspects of networked intelligent manufacturing systems. This means covering a wide array of application domains and user requirements. In such scenarios it is not feasible to define a single protocol for all situations. Hence, a multi-protocol approach is required. OPC UA has strong backing from Industry 4.0 as the protocol for the Industrial Internet of Things. Interoperability of OPC UA has been investigated in the context of migration from legacy and with protocols such as DPWS. Additionally HTTP and CoAP have been investigated as possible transport mediums. However, OPC UA interoperability has not been investigated within a multi-protocol settings and no generic protocol translation exists. This paper proposes an OPC UA translator following the service translator model proposed in the Arrowhead project. Utilizing a mapping to intermediate format, it can be used along side CoAP, HTTP and MQTT protocols.

Protocol interoperability of OPC UA in service oriented architectures

Accurate and fast-convergent time synchronization is very important for wireless sensor networks. The flooding time synchronization converges fast, but its transmission delay and by-hop error accumulation seriously reduce the synchronization accuracy. In this article, a rapid-flooding multiple one-way broadcast time-synchronization (RMTS) protocol for large-scale wireless sensor networks is proposed. To minimize the by-hop error accumulation, the RMTS uses maximum likelihood estimations for clock skew estimation and clock offset estimation, and quickly shares the estimations among the networks. As a result, the synchronization error resulting from delays is greatly reduced, while faster convergence and higher-accuracy synchronization is achieved. Extensive experimental results demonstrate that, even over 24-hops networks, the RMTS is able to build accurate synchronization at the third synchronization period, and moreover, the by-hop error accumulation is slower when the network diameter increases.

Rapid-Flooding Time Synchronization for Large-Scale Wireless Sensor Networks

The ever-increasing number of WSN deployments based on a large number of battery-powered, low-cost sensor nodes, which are limited in their computing and power resources, puts the focus of WSN time synchronization research on three major aspects, i.e., accuracy, energy consumption and computational complexity. In the literature, the latter two aspects have not received much attention compared to the accuracy of WSN time synchronization. Especially in multi-hop WSNs, intermediate gateway nodes are overloaded with tasks for not only relaying messages but also a variety of computations for their offspring nodes as well as themselves. Therefore, not only minimizing the energy consumption but also lowering the computational complexity while maintaining the synchronization accuracy is crucial to the design of time synchronization schemes for resource-constrained sensor nodes. In this paper, focusing on the three aspects of WSN time synchronization, we introduce a framework of reverse asymmetric time synchronization for resource-constrained multi-hop WSNs and propose a beaconless energy-efficient time synchronization scheme based on reverse one-way message dissemination. Experimental results with a WSN testbed based on TelosB motes running TinyOS demonstrate that the proposed scheme conserves up to 95% energy consumption compared to the flooding time synchronization protocol while achieving microsecond-level synchronization accuracy.

A Beaconless Asymmetric Energy-Efficient Time Synchronization Scheme for Resource-Constrained Multi-Hop Wireless Sensor Networks

WIA-PA (Wireless Networks for Industrial Automation-Process Automation) standard has become one of the three major IEC (International Electrotechnical Commission) standards for industrial wireless networks technology, and multi-channel frequency hopping mechanism is significant for the performance of WIA-PA networks. Existing AFH (adaptive frequency hopping) mechanism for WIA-PA networks is based on retransmissions and requires multiple interactions, including notifications and acknowledgements. It increases the complexity and resource consumption of the networks. To solve the problem, we consider an efficient channel utilization scheme based on link skipping. In our proposed scheme, channel conditions are evaluated from channel history information in three levels: single point level, cluster level and whole network level, and then the network devices synthesize the evaluation results and skip the interfered links flexibly before transmitting packets. Experimental results verify that the proposed scheme decreases the packet loss probability, as well as accelerates the reaction time of channel interference appearance effectively.

Lun Shao

Papers

An Efficient Channel Utilization Scheme for WIA-PA Industrial Wireless Networks Based on Link Skipping