Short-range Links Research Articles

Wideband Lorenz Resonance Reconfigurable Metasurface for 5G+ Communications

Reconfigurable intelligent surfaces (RIS) have been considered as a promising solution to enhance the spectrum and energy efficiency of the 5G+ and future 6G wireless communication systems. The performance of RIS will become the key metric of these communication systems. In this paper, we proposed a wideband Lorenz resonance-based metasurface reconfigurable reflectarray (MSRRA) realization scheme with low energy consumption targeted at the center frequency of 28 GHz. A compact voltage bias network for the varactor diodes is carefully designed to reduce losses in RF current and the influence of the bias circuit on the radiating element effectively. An equivalent circuit model for the MSRRA unit cell is also introduced to predict the properties of the MSRRA system, which can be used to optimize the MSRRA design efficiently. In the experimental tests, the proposed MSRRA system can be optimized to cover a dynamic reflection phase range of over 300° with a bandwidth of 3.83 GHz, which is consistent with the simulation results. The measured single-scattering beam bandwidth is 1.85 GHz at the center frequency of 28 GHz, which can fully cover the whole n257 channel of 5G NR. The proposed continuous tunable MSRRA can support 5G+ and 6G indoor, short-range links, and outdoor point-to-point communications.

Practical Challenges in Hybrid Communication Ecosystems Based on ITS-G5 and LTE for CACC and GLOSA

In this paper we report the implementation and experimental evaluation of a proposed hybrid communication ecosystem for CCAM applications such as cooperative adaptive cruise control (CACC) and smart intersections. Three wireless technologies have been suggested for communications between vehicles and intelligent traffic lights and are evaluated in this work: ITS-G5 based on IEEE 802.11p and LTE sidelink with PC5 air interface for direct short range links, and regular mobile LTE with LTE Uu air interface for long range or indirect links. The applications used are independent of the communication channel, to enable a comparison on the application level of the different communication technologies. Field experiments were carried out with two CACC-equipped vehicles and three intelligent traffic lights in two field test locations under ideal, i.e., no-traffic, conditions and with real traffic. Experimental results related to CACC show that the best performance in terms of latency is achieved by the ITS-G5 system, while LTE PC5 and LTE Uu links show a penalty of 20 and 50 ms respectively. However, experimental results show that all three communication technologies were still able to guarantee string stable performance of the vehicle platoon. Regarding the smart intersections, an analysis based on field measurements and comparison between long- and short-range solutions is proposed; the analysis includes the impact of each channel on the applications such as speed advisory and green light prediction. The reported experimental evaluation shows the potential of current mobile technologies for CCAM use cases and highlights the way for further CCAM applications based on 5G and beyond mobile networks.

Performance of THz Communications Over Cascaded RISs: A Practical Solution to the Over-Determined Formulation

As a last resort for radio frequency communication, Terahertz bands (0.1-10 THz) are targeted thanks to their ability to provide ultra-wide bandwidth satisfying varieties of emerging applications. However, the waves propagating at THz frequencies suffer from high losses due to absorption in air molecules which forces their use into short-range links. We propose a multi-hop system to extend the range of THz links with the aid of multiple passive reconfigurable intelligent surfaces (RIS). In contrast with existing literature, we address the challenge of the over-determined system of equations arising from optimizing the phases of cascaded RISs taking into account the practical case of highly directional antennas and spatially correlated channels in THz bands. We propose an efficient method to jointly optimize the phases induced by the RISs in order to maximize the power at the receiver side.

Optimal Interference for Device to Device Communication Underlaying Cellular Network

Device to Device (D2D) communication can effectively improve the spectrum eficiency and reduce the load of Base Station in cellular networks. However, when D2D users and cellular users share the wireless channels, it will bring signal interference for the cellular networks. In order to achieve mutual interference between users and base stations, and increase the spectrumutilization efficiency and energy utilization efficiency, this paper proposes a method control algorithm based on bearnforrning and interference alignment in D2D communication underlaying cellular networks. Simulation results show that the proposed algorithm can effectively reduce the interference of the BS transrnitting signal for D2D pais and significantly improve system capacity. Furthermore, D2D communication is more applicable to short-range links.

Outage probability analysis in multi-user FSO/RF and UAV-enabled MIMO communication networks

This paper considers a mixed free-space optical/radio frequency (FSO/RF) system, which facilitates the communication between a ground central unit (CU) and multiple ground users (GUs) via a hovering unmanned aerial vehicle (UAV) acting as a decode-and-forward (DF) aerial relay. It is considered that the CU employs multiple transmit apertures and is interconnected with the aerial relay via an FSO link with transmit aperture selection (TAS), whereas the relay communicates with the GUs over multiple-input multiple-output (MIMO) RF links with orthogonal space–time block coding (OSTBC) transmission. It is assumed that the optical channels are mainly affected by atmospheric attenuation as well as geometric and misalignment loss (GML). Besides, the atmospheric turbulence is assumed weak for short-range links. Also, fully correlated shadowed conditions are considered in the RF links and the MIMO channels are modeled using the Nakagami/Inverse Gamma (IG) composite fading distribution. Opportunistic GU scheduling is applied in the downlink and novel closed-form mathematical formulas for the outage probability (OP) are derived. The results demonstrate the theoretical derivations and the performance benefits of the proposed approach.

Energy and performance-aware balancing in establishing an emergency wireless communication network

In a disaster situation, natural or human-made disasters, establishing an emergency wireless network in these circumstances is very important to save lives. It is imperative to ensure the network’s ability to connect all people in the disaster area, with an optimum capacity to handle the information traffic while consuming less power. These factors are critical when designing such a network. The clustering technique has improved wireless network performance in throughput and power consumption. However, there are still difficulties when applying this technique to such a situation, essentially selecting cluster heads (CHs) and connecting them to the nearby functional base station (BS). This paper devises an algorithm (CCaCH/SCH-S) to create clusters and select CHs appropriately. Once clusters are created and CHs are selected, the connection between CHs and the relay station (RN) is established using long-range links. CHs are responsible for aggregating data from their members and forward the information to RN. Each cluster consists of a main-cluster with its CH and a sub-cluster with its sub-cluster head (SCH); both use short-range links. In this approach, the selection of CH and SCH was determined by the residual battery power. The proposed approach was investigated against the system capacity, power consumption, and the required time to establish communication to the functional areas. Different network parameters and clustering approaches were simulated using MATLAB. The proposed approach minimized the users’ equipment (UEs) power consumption by 5.9% comparing to a multi-hop approach and 9.4% compared to the single-hop approach. Furthermore, the proposed approach improved the network capacity up to 7% and 32.6% better than multi-hop and single-hop approaches, respectively.

A Simple Propagation Model to Characterize the Effects of Multiple Human Bodies Blocking Indoor Short-Range Links at 28 GHz

This study aims to provide a simple approach to characterize the effects of scattering by human bodies in the vicinity of a short-range indoor link at 28 GHz while the link is fully blocked by another body. In the study, a street canyon propagation characterized by a four-ray model is incorporated to consider the human bodies. For this model, the received signal is assumed to be composed of a direct component that is exposed to shadowing due to a human body blocking the link and a multipath component due to reflections from human bodies around the link. In order to predict the attenuation due to shadowing, the double knife-edge diffraction (DKED) model is employed. Moreover, to predict the attenuation due to multipath, the reflected fields from the human bodies around the link are used. The measurements are compared with the simulations in order to evaluate the prediction accuracy of the model. The acceptable results achieved in this study suggest that this simple model might work correctly for short-range indoor links at millimeter-wave (mmWave) frequencies.

Modelling Energy Distribution in Residential Areas: A Case Study Including Energy Storage Systems in Catania, Southern Italy

Complexity is a widely acknowledged feature of urban areas. Among the different levels to which this definition applies, the energy sector is one of the most representative of this way of conceiving cities. An evidence of this complexity can be detected in the growing impact of prosumers. Prosumers produce energy to meet their own demands, distribute it directly to neighbors and, eventually, store the energy neither consumed nor distributed. The modelling of distribution networks is a challenging task that requires ad hoc models to simulate the mutual energy exchanges occurring among prosumers. To serve at this scope, this paper proposes an agent-based model aiming at determining which operating conditions enhance the energy distribution among prosumers and diminish the supply from traditional power plants. An application of the model within a residential territory is then presented and simulations are conducted under two scenarios: the first investigating the distribution among prosumers equipped with photovoltaics (PV) systems, the second integrating energy storage systems to PV panels. Both scenarios are studied at varying the installed PV capacity within the territory, the allowed distance of connection among prosumers, as well as the rate of utilization of the links of the network. Results from the simulated case study reveal that the energy distribution among prosumers can be enhanced by providing short-range links for the electricity exchange. Similar advantages can be achieved by integrating storage systems to PV, along with a significant reduction in the electricity requested to the centralized grid.

Millimeter Wave Propagation in Long Corridors and Tunnels—Theoretical Model and Experimental Verification

The development of the Fifth-Generation (5G) of cellular communications considers bands in millimeter waves (MMW) for indoor, short-range links. The propagation of MMW is affected by atmospheric and weather conditions, specular reflections from surfaces, and the directivity of the antennas. The short wavelength enables utilization of a quasi-optical propagation model for the description of indoor multi-path scenarios. A study of MMW propagation in tunnels, long corridors, or canyons is carried out using ray-tracing to evaluate the link budget and group delay. The analysis considers radiation patterns of both transmitting and receiving antennas, deriving a criterion for the number of dominating rays. Error analysis demonstrates the convergence of the method, while using a finite number of reflected rays. Experiments in a small-scale tunnel model demonstrate the accuracy of the analysis.

Design and Packaging of a Robust 120-GHz OOK Receiver Used in a Short-Range Dielectric Fiber Link

This letter presents the design of a 120 GHz receiver in 28nm CMOS with a replica biasing temperature compensation loop as part of a short-range Gbps communication link with a dielectric fiber. A comparison is made between different biasing methods for a millimeter-wave envelope detector to ensure reliable operation over an operating range from −40 °C to +200 °C. Also, a robust packaging is proposed using an on-chip antenna to couple with the dielectric fiber. The design is followed by verification with measurements.

基于中短距离星间链路的可见光通信及性能分析

To meet constraints on size, weight, and power consumption in small satellite platforms and explore alternative solutions for radio frequency and laser-based communication in medium- and short-distance inter-satellite links, this study explores the feasibility of visible-light communication (VLC) based medium- and short-distance inter-satellite communication in multi-satellite networks. Using the satellite tool kit (STK), the binary star formation flying configuration is constructed, background-light noise introduced by the sun and stars is quantitatively analyzed, and a medium- and short-range inter-satellite VLC link model is constructed. Then, to improve the link capacity and reliability, the VLC link is further developed into a single-input multi-output VLC (SIMO-VLC) system. The influences of different diversity merging algorithms on the link's performance are evaluated by numerical simulation. Simulation results show that the stray light power introduced by solar radiation is below 10 μW throughout most of the time period, and the background light power introduced from the ground is reduced by 75%. In order to achieve a data transmission rate of 112.5 Mbit/s and a bit error rate of 1×10-6 within 20 km, the light power required by the system is at least 4.55 W. Compared with the single-input single-output system, the SIMO-based diversity detection scheme can achieve better performance, and the required transmission power and communication distance are effectively improved with the increase of the receiving branch, which can provide a reference for the design of VLC-based inter-satellite links and extending their outdoor application scenarios. © 2019, Chinese Lasers Press. All right reserved.

Rain Statistics Investigation and Rain Attenuation Modeling for Millimeter Wave Short-Range Fixed Links

Millimeter wave (mmWave) communication is a key technology for fifth generation (5G) and beyond communication networks. However, the communication quality of the radio link can be largely affected by rain attenuation, which should be carefully taken into consideration when calculating the link budget. In this paper, we present results of weather data collected with a PWS100 disdrometer and mmWave channel measurements at 25.84 GHz (K band) and 77.52 GHz (E band) using a custom-designed channel sounder. The rain statistics, including rain intensity, rain events, and rain drop size distribution (DSD) are investigated for one year. The rain attenuation is predicted using the DSD model with Mie scattering and from the model in ITU-R P.838-3. The distance factor in ITU-R P.530-17 is found to be inappropriate for a short-range link. The wet antenna effect is investigated and additional protection of the antenna radomes is demonstrated to reduce the wet antenna effect on the measured attenuation.

Reaching Fault Diagnosis Consensuson a Multiple Damage Unreliable Wireless Sensor Network

ABSTRACT Wireless sensor networks (WSNs) are more and more frequently seen as a solution to large-scale tracking and monitoring applications, because of their low-data-rate, low-energy-consumption, and short-range link network which provides an opportunity to monitor and control the physical world to a previously unprecedented scale and resolution. In order to achieve fault-tolerance of WSN, one must deal with the consensus problem. The consensus problem occurs when the fault-free nodes in a distributed system can reach a common agreement before performing specified in instances where faults may exist. The distributed consensus is discussed in previous works. Most of consensus protocols can reach an agreement by the way of fault masking. However, few of them can detect and locate the faulty components. If the faulty components can be detected and located, then the network can be reconfigured to maintain the performance and integrity of a distributed system. In this study, a new protocol is proposed which can tolerate, detect and locate the maximum number of dual failure transmission media to solve the consensus problem in a WSN.

Integrated Shield Edge Diffraction Model for Narrow Obstructing Objects

A new simple and accurate model defined as shield edge diffraction is derived and validated suitable for frequencies above 10 GHz diffracting around obstructions that are narrow compared to the Fresnel zone width. The model includes new simple Fresnel diffraction parameters similar to those used with traditional knife edge diffraction, which can in the same way be integrated into deterministic and empirical path loss models. The capability of the model extends beyond current single and double knife edge models whereby it includes the effects of the antennas’ far-field distances as well as their gain and phase patterns, which subsequently have a severe effect on the diffraction loss in short-range links. The models are validated using both the anechoic chamber as well as real environment-based measurements at 10–12 and 26 GHz.

High-Speed DMT and VCSEL-Based MMF Transmission Using Pre-Distortion

We present high-speed single-channel discrete multitone (DMT) operations of directly modulated 850-nm vertical-cavity surface-emitting lasers (VCSEL). Successful transmission of 135 Gb/s over 10 m of OM4 multi-mode fiber (MMF) and 114 Gb/s over 550 m is demonstrated below the 7 % overhead hard-decision forward error correction (FEC) bit error rate (BER) limit. At higher BER limits, i.e. 20 % overhead soft-decision FEC, which are of arising interest for these high-speed short-range links, data rates of up to 161 Gb/s are presented. This is enabled by high-bandwidth low-noise VCSEL, which operate in quasi-single mode to overcome the mode dispersion limitations of the MMF. The applied modulation format is DMT in combination with a Volterra-filter-based pre-distortion approach, which pre-compensates the linear and nonlinear behavior of the transmission system, primarily the digital-analog converter, the VCSEL, the MMF, and the photoreceiver. Furthermore, a detailed investigation of the pre-distortion is given by experimental means, showing that the optimum amount of pre-distortion depends on the applied components and the signal bandwidth. This makes it challenging to predict the optimum; however, a pure electrical pre-distortion offers already a fair gain in performance.

Guest Editorial

Guest Editorial

5G Millimeter-Wave and D2D Symbiosis: 60 GHz for Proximity-Based Services

The characteristics of two key communication technologies in 5G, namely, D2D and mmWave, are complementary. While D2D facilitates the communication of nearby mobile nodes, mmWave provides very high throughput short-range links by using carrier frequencies beyond 30 GHz, and reduces interference by using directional communication. This directly addresses two critical issues in cellular networks, namely, the increasing number of users and the high throughput requirements. In this article, we explore the above symbiosis of D2D and mmWave. More precisely, we integrate mmWave communications into the 3GPP framework for D2D communication, that is, ProSe. To this end, we design the message exchange among entities in the ProSe architecture to support the discovery, establishment, and maintenance of mmWave links. Further, we evaluate the performance of an mmWave D2D system for the case of a picocell operating in the 60 GHz band. We experimentally analyze the benefits of combining D2D and 60 GHz communication. Our results show that this combination improves performance in terms of throughput by up to 2.3 times.

Short-range links beyond 100Gb/s with vertical-cavity surface-emitting lasers

Short-range links beyond 100Gb/s with vertical-cavity surface-emitting lasers

SleepTalker: A ULV 802.15.4a IR-UWB Transmitter SoC in 28-nm FDSOI Achieving 14 pJ/b at 27 Mb/s With Channel Selection Based on Adaptive FBB and Digitally Programmable Pulse Shaping

Achieving wireless communications at 5–30 Mb/s in energy-harvesting Internet-of-Things (IoT) applications requires energy efficiencies better than 100 pJ/b. Impulse-radio ultrawideband (UWB) communications offer an efficient way to achieve high data rate at ultralow power for short-range links. We propose a digital UWB transmitter (TX) system-on-chip (SoC) designed for ultralow voltage in 28-nm FDSOI CMOS. It features a PLL-free architecture, which exploits the duty-cycling nature of impulse radio through aggressive duty cycling within the pulse modulation time slot for high energy efficiency and minimum jitter accumulation. Wide-range on-chip adaptive forward back biasing is used for threshold voltage reduction, PVT compensation, and tuning of both the carrier frequency and the output power. To ensure spectral compliance with output power regulations without the use of bulky and expensive off-chip filters, a programmable pulse-shaping functionality is integrated in the digital power amplifier based on a 7–9-GS/s, 5-b current DAC. Operated at 0.55 V, it achieves a record energy efficiency of 14 pJ/b for the TX alone and 24 pJ/b for the complete SoC with embedded power management. The TX SoC occupies a core area of 0.93 mm2.

Joint storage assignment for D2D offloading systems

D2D offloading reduces the load of cellular network by asking mobile nodes to download content directly from storage of neighboring helpers via short range links. In this paper, we introduce a novel storage assignment scheme that can enhance storage utilization for D2D networks that have different types of storage nodes. Unlike traditional D2D systems that only use storage as static content cache, our scheme uses on-demand relaying to enhance storage utilization. Our on-demand relaying scheme replicates rare content when it is requested. Therefore, the proposed scheme can greatly increase the amount of content supported by the offloading system. We develop a convex optimization based algorithm to find the optimal storage assignment tradeoff between static caching and on-demand relaying. Numerical results and real-world trace-driven simulations show that our algorithm can achieve 30% reduction in offloading failure rate compared to static schemes.