Internet of Things (IoT) has provided a promising opportunity to build powerful industrial systems and applications by leveraging the growing ubiquity of radio-frequency identification (RFID), and wireless, mobile, and sensor devices. A wide range of industrial IoT applications have been developed and deployed in recent years. In an effort to understand the development of IoT in industries, this paper reviews the current research of IoT, key enabling technologies, major IoT applications in industries, and identifies research trends and challenges. A main contribution of this review paper is that it summarizes the current state-of-the-art IoT in industries systematically.

Internet of Things in Industries: A Survey

Fog/edge computing has been proposed to be integrated with Internet of Things (IoT) to enable computing services devices deployed at network edge, aiming to improve the user’s experience and resilience of the services in case of failures. With the advantage of distributed architecture and close to end-users, fog/edge computing can provide faster response and greater quality of service for IoT applications. Thus, fog/edge computing-based IoT becomes future infrastructure on IoT development. To develop fog/edge computing-based IoT infrastructure, the architecture, enabling techniques, and issues related to IoT should be investigated first, and then the integration of fog/edge computing and IoT should be explored. To this end, this paper conducts a comprehensive overview of IoT with respect to system architecture, enabling technologies, security and privacy issues, and present the integration of fog/edge computing and IoT, and applications. Particularly, this paper first explores the relationship between cyber-physical systems and IoT, both of which play important roles in realizing an intelligent cyber-physical world. Then, existing architectures, enabling technologies, and security and privacy issues in IoT are presented to enhance the understanding of the state of the art IoT development. To investigate the fog/edge computing-based IoT, this paper also investigate the relationship between IoT and fog/edge computing, and discuss issues in fog/edge computing-based IoT. Finally, several applications, including the smart grid, smart transportation, and smart cities, are presented to demonstrate how fog/edge computing-based IoT to be implemented in real-world applications.

A Survey on Internet of Things: Architecture, Enabling Technologies, Security and Privacy, and Applications

Frequencies from 100 GHz to 3 THz are promising bands for the next generation of wireless communication systems because of the wide swaths of unused and unexplored spectrum. These frequencies also offer the potential for revolutionary applications that will be made possible by new thinking, and advances in devices, circuits, software, signal processing, and systems. This paper describes many of the technical challenges and opportunities for wireless communication and sensing applications above 100 GHz, and presents a number of promising discoveries, novel approaches, and recent results that will aid in the development and implementation of the sixth generation (6G) of wireless networks, and beyond. This paper shows recent regulatory and standard body rulings that are anticipating wireless products and services above 100 GHz and illustrates the viability of wireless cognition, hyper-accurate position location, sensing, and imaging. This paper also presents approaches and results that show how long distance mobile communications will be supported to above 800 GHz since the antenna gains are able to overcome air-induced attenuation, and present methods that reduce the computational complexity and simplify the signal processing used in adaptive antenna arrays, by exploiting the Special Theory of Relativity to create a cone of silence in over-sampled antenna arrays that improve performance for digital phased array antennas. Also, new results that give insights into power efficient beam steering algorithms, and new propagation and partition loss models above 100 GHz are given, and promising imaging, array processing, and position location results are presented. The implementation of spatial consistency at THz frequencies, an important component of channel modeling that considers minute changes and correlations over space, is also discussed. This paper offers the first in-depth look at the vast applications of THz wireless products and applications and provides approaches for how to reduce power and increase performance across several problem domains, giving early evidence that THz techniques are compelling and available for future wireless communications.

/pdf/wireless-communications-and-applications-above-100-ghz-arnwwogno0.pdf

Wireless Communications and Applications Above 100 GHz: Opportunities and Challenges for 6G and Beyond

Intelligent reflecting surface (IRS) is an enabling technology to engineer the radio signal propagation in wireless networks. By smartly tuning the signal reflection via a large number of low-cost passive reflecting elements, IRS is capable of dynamically altering wireless channels to enhance the communication performance. It is thus expected that the new IRS-aided hybrid wireless network comprising both active and passive components will be highly promising to achieve a sustainable capacity growth cost-effectively in the future. Despite its great potential, IRS faces new challenges to be efficiently integrated into wireless networks, such as reflection optimization, channel estimation, and deployment from communication design perspectives. In this paper, we provide a tutorial overview of IRS-aided wireless communications to address the above issues, and elaborate its reflection and channel models, hardware architecture and practical constraints, as well as various appealing applications in wireless networks. Moreover, we highlight important directions worthy of further investigation in future work.

Intelligent Reflecting Surface-Aided Wireless Communications: A Tutorial

http://www.acsu.buffalo.edu/~jmjornet/papers/2014/j1.pdf

Full length article: Terahertz band: Next frontier for wireless communications

We propose a new spectrum allocation strategy for terahertz (THz) band communication (THzCom) systems. Specifically, we design multi-band-based spectrum allocation with adaptive sub-band bandwidth (ASB), by allowing to divide the spectrum of interest into sub-bands with unequal bandwidths. Due to the frequency and distance-dependent nature of the molecular absorption loss, the variation in this loss between the sub-bands would be very high at the THz band when equal sub-band bandwidth (ESB) is considered, as in the literature. The proposed strategy reduces this variation by allowing changes in the sub-band bandwidth, which leads to an overall improvement in the data rate performance. To study the impact of our strategy, we formulate an optimization problem, with the main focus on spectrum allocation, to determine the optimal sub-band bandwidth and transmit power. Thereafter, we propose reasonable approximations and transformations to solve the formulated problem. Aided by numerical results, we show that by enabling and optimizing ASB, a significantly higher data rate can be achieved by our strategy, compared to adopting ESB, and it is more beneficial to adopt ASB when the spectrum with the highest average molecular absorption loss within the THz transmission window is selected during spectrum allocation.

Adaptive Sub-band Bandwidth-Enabled Spectrum Allocation for Terahertz Communication Systems

Nanonetworks are comprised of nano-sized communication devices which can perform simple tasks such as computation, data storage and actuation at the nanoscale. However, due to the error-prone wireless links in the Terahertz band (0.1-10.0 THz) and very limited energy storage capacity in nanodevices, the efficient and effective error control protocols are necessary for nanonetworks. In this paper, firstly, a novel error control strategy with probing (ECP) mechanism for nanonetworks powered by energy harvesting is proposed. In particular, each data packet is transmitted only after the communication of one probing packet is successful. Secondly, the energy state model as well as state transition rate matrix by considering the energy harvesting-consumption process is presented based on the extended Markov chain approach. Thirdly, the impact of different packets energy consumption on state transition and the state probability distribution based on the above matrix are comprehensively investigated. Finally, analytical and numerical results are provided to evaluate the performance of the proposed ECP mechanism in terms of end-to-end successful packet delivery probability, end-to-end packet delay, achievable throughput and energy consumption. The results show that ECP mechanism improves the energy utilization and successful data packet delivery probability compared to ARQ schemes.

ECP: error control with probing for EM-based nanonetworks powered by energy harvesting

With multi-GHz bandwidth, Terahertz (THz) communication has drawn increasing attention in the sixth generation (6G) and beyond communication systems. Although different hybrid beamforming algorithms have been developed to improve array gain and spectral efficiency in both single-user and multiuser systems, they rely on the compact array architecture and far-field approximation of propagation. In the THz band, due to the limited number of multipath and shortage of spatial degree freedom of the channel, the spatial mulitplexing gain is constrained. In this paper, a widely-spaced multi-subarray (WSMS) hybrid beamforming architecture is proposed in a multi-user network, to harness both the inter and intra-multiplexing gains in the enlarged near-field propagation region. Specifically, the novel structure of the hybrid beamforming matrices is analyzed, and an alternating optimization algorithm to maximize the sum rate is designed. Simulation results demonstrate that the proposed algorithm under the WSMS architecture outperforms the existing beamforming schemes in the traditional architectures.

Alternating Optimization Based Hybrid Beamforming in Terahertz Widely-spaced Multi-subarray Systems

We conduct novel coverage probability analysis of downlink transmission in a three-dimensional (3D) terahertz (THz) communication (THzCom) system. In this system, we address the unique propagation properties in THz band, e.g., absorption loss, super-narrow directional beams, and high vulnerability towards blockage, which are fundamentally different from those at lower frequencies. Different from existing studies, we characterize the performance while considering the effect of 3D directional antennas at both access points (APs) and user equipments (UEs), and the joint impact of the blockage caused by the user itself, moving humans, and wall blockers in a 3D environment. Under such consideration, we develop a tractable analytical framework to derive a new expression for the coverage probability by examining the regions where dominant interferers (i.e., those can cause outage by themselves) can exist, and the average number of interferers existing in these regions. Aided by numerical results, we validate our analysis and reveal that ignoring the impact of the vertical heights of THz devices in the analysis leads to a substantial underestimation of the coverage probability. We also show that it is more worthwhile to increase the antenna directivity at the APs than at the UEs, to produce a more reliable THzCom system.

Coverage Analysis for 3D Terahertz Communication Systems

https://link-springer-com-443.webvpn.jmu.edu.cn/content/pdf/10.1007%2F978-3-319-78262-1_228.pdf

Chong Han

Papers

Adaptive Sub-band Bandwidth-Enabled Spectrum Allocation for Terahertz Communication Systems

ECP: error control with probing for EM-based nanonetworks powered by energy harvesting

Alternating Optimization Based Hybrid Beamforming in Terahertz Widely-spaced Multi-subarray Systems

Coverage Analysis for 3D Terahertz Communication Systems

Channel Modeling of Microscale Terahertz Communication