A Survey of Techniques for Discovering, Using, and Paying for Third-Party IoT Sensors.

The Internet of Things (IoT) includes billions of sensors and actuators (which we refer to as IoT devices) that harvest data from the physical world and send it via the Internet to IoT applications to provide smart IoT services and products. Deploying, managing, and maintaining IoT devices for the exclusive use of an individual IoT application is inefficient and involves significant costs and effort that often outweigh the benefits. On the other hand, enabling large numbers of IoT applications to share available third-party IoT devices, which are deployed and maintained independently by a variety of IoT device providers, reduces IoT application development costs, time, and effort.

Demonstration of Spatial Modulation Using a Novel Active Transmitter Detection Scheme with Signal Space Diversity in Optical Wireless Communications.

Line-of-sight (LOS) indoor optical wireless communications (OWC) enable a high data rate transmission while potentially suffering from optical channel obstructions. Additional LOS links using diversity techniques can tackle the received signal performance degradation, where channel gains often differ in multiple LOS channels. In this paper, a novel active transmitter detection scheme in spatial modulation (SM) is proposed to be incorporated with signal space diversity (SSD) technique to enable an increased OWC system throughput with an improved bit-error-rate (BER).

Investigation on repetition-coding and space-time-block-coding for indoor optical wireless communications employing beam shaping based on orbital angular momentum modes.

In this paper, we propose a novel beam shaping technique based on orbital angular momentum (OAM) modes for indoor optical wireless communications (OWC). Furthermore, we investigate two spatial diversity techniques, namely repetition-coding (RC) and Alamouti-type orthogonal space-time-block-coding (STBC) for indoor OWC employing the new beam shaping technique. The performance of both diversity schemes is systematically analyzed and compared under different beam shaping techniques using different OAM modes with different power ratios of the modes.

IoT Device Integration and Payment via an Autonomic Blockchain-Based Service for IoT Device Sharing.

The Internet of Things (IoT) incorporates billions of IoT devices (e.g., sensors, cameras, wearables, smart phones, as well as other internet-connected machines in homes, vehicles, and industrial plants), and the number of such connected IoT devices is currently growing rapidly.

Direct Electrohydrodynamic Patterning of High-Performance All Metal Oxide Thin-Film Electronics.

In this paper, we propose a scalable approach toward all-printed high-performance metal oxide thin-film transistors (TFTs), using a high-resolution electrohydrodynamic (EHD) printing process. Direct EHD micropatterning of metal oxide TFTs is based on diverse precursor solutions to form semiconducting materials (InO, In-Ga-ZnO (IGZO)), conductive metal oxide (Sn-doped InO (ITO)), as well as aluminum oxide (AlO) gate dielectric at low temperatures. The fully printed TFT devices exhibit excellent electron transport characteristics (average electron mobilities of up to 117 cm V s), negligible hysteresis, excellent uniformity, and stable operation at low-operating voltage.

Predicting the mean first passage time (MFPT) to reach any state for a passive dynamic walker with steady state variability.

Idealized passive dynamic walkers (PDW) exhibit limit cycle stability at steady state. Yet in reality, uncertainty in ground interaction forces result in variability in limit cycles even for a simple walker known as the Rimless Wheel (RW) on seemingly even slopes. This class of walkers is called metastable walkers in that they usually walk in a stable limit cycle, though guaranteed to eventually fail.

Multi-cell coordination for 60 GHz RoF fronthaul enabled by a non-orthogonal multiple access scheme without successive interference cancellation.

We propose and experimentally demonstrate a non-orthogonal multiple access (NOMA) enabled 60 GHz radio-over-fiber (RoF) fronthaul system with coordinated base stations, improving the data rate and coverage of 60 GHz RoF systems. First, coordinated multipoint transmission using space-time block coding (STBC) is adopted in fronthaul, achieving 1.3 dB improvement in receiver sensitivity compared to two fronthaul links' transmission without STBC.

High-speed indoor optical wireless communication system employing a silicon integrated photonic circuit.

Beam-steering-based optical wireless technologies are being widely investigated due to the capability of providing high-speed wireless connectivity in indoor applications. However, high-speed indoor optical wireless systems are traditionally realized with discrete bulky components, significantly limiting their practical applications. In this Letter, we demonstrate an infrared optical wireless communication system employing a miniaturized silicon integrated photonic circuit for beam steering for the first time.

Indoor infrared optical wireless localization system with background light power estimation capability.

The indoor user localization function is in high demand for high-speed wireless communications, navigations and smart-home applications. The optical wireless technology has been used to localize end users in indoor environments. However, its accuracy is typically very limited, due to the ambient light, which is relatively strong.

Secure multiple access for indoor optical wireless communications with time-slot coding and chaotic phase.

In this paper, we report a novel mechanism to simultaneously provide secure connections for multiple users in indoor optical wireless communication systems by employing the time-slot coding scheme together with chaotic phase sequence. The chaotic phase sequence is generated according to the logistic map and applied to each symbol to secure the transmission. Proof-of-concept experiments are carried out for multiple system capacities based on both 4-QAM and 16-QAM modulation formats, i.

Time-slot coding scheme for multiple access in indoor optical wireless communications.

This letter proposes what we believe is a novel time-slot coding (TSC) scheme to provide optical wireless communications to multiple users simultaneously with limited multiuser interference. We studied the proposed TSC experimentally and our results show that the code alignment tolerance, due to imperfect timing during the code generation process in practice, is 90.2%, 91.

Tuneable graphene nanopores for single biomolecule detection.

Solid-state nanopores are promising candidates for next generation DNA and protein sequencing. However, once fabricated, such devices lack tuneability, which greatly restricts their biosensing capabilities. Here we propose a new class of solid-state graphene-based nanopore devices that exhibit a unique capability of self-tuneability, which is used to control their conductance, tuning it to levels comparable to the changes caused by the translocation of a single biomolecule, and hence, enabling high detection sensitivities.

Highly Effective Conductance Modulation in Planar Silicene Field Effect Devices Due to Buckling.

Silicene is an exciting two-dimensional material that shares many of graphene's electronic properties, but differs in its structural buckling. This buckling allows opening a bandgap in silicene through the application of a perpendicular electric field. Here we show that this buckling also enables highly effective modulation of silicene's conductance by means of an in-plane electric field applied through silicene side gates, which can be realized concurrently within the same silicene monolayer.

Experimental demonstration of a novel indoor optical wireless localization system for high-speed personal area networks.

In this Letter, we propose a novel indoor localization system based on optical wireless technology. By using the same architecture as the high-speed full-duplex indoor optical wireless communication system, the "search and scan" process, and the added transmission power and beam footprint information in the "search and scan" message, indoor localization functionality is achieved. Proof-of-concept experiments are carried out, and results show that an average error of <15  cm is achieved with a localization beam size of 1 m.

Experimental demonstration of free-space based 120 Gb/s reconfigurable card-to-card optical interconnects.

In this Letter, we propose and experimentally demonstrate a free-space based reconfigurable card-to-card optical interconnect architecture with 16-carrierless-amplitude-phase modulation. Experimental results show that up to 120 Gb/s (3×40  Gb/s) flexible interconnection can be achieved for up to 30 cm distance with a worst-case receiver sensitivity of -9.70  dBm.

Asymmetrically-gated graphene self-switching diodes as negative differential resistance devices.

We present an asymmetrically-gated Graphene Self-Switching Diode (G-SSD) as a new negative differential resistance (NDR) device, and study its transport properties using nonequilibrium Green's function (NEGF) formalism and the Extended Huckel (EH) method. The device exhibits a new NDR mechanism, in which a very small quantum tunnelling current is used to control a much-larger channel conduction current, resulting in a very pronounced NDR effect. This NDR effect occurs at low bias voltages, below 1 V, and results in a very high current peak in the μA range and a high peak-to-valley current ratio (PVCR) of 40.

High-speed reconfigurable card-to-card optical interconnects based on hybrid free-space and multi-mode fiber propagations.

In this paper, a high-speed reconfigurable card-to-card optical interconnect architecture based on hybrid free-space and multi-mode fiber (MMF) propagation is proposed. The use of free-space signal transmission provides flexibility and reconfigurability and the MMF extends the achievable interconnection range. A printed-circuit-board (PCB) based integrated optical interconnect module is designed and developed and proof-of-concept demonstration experiments are carried out.

All-graphene planar self-switching MISFEDs, Metal-Insulator-Semiconductor Field-Effect Diodes.

Graphene normally behaves as a semimetal because it lacks a bandgap, but when it is patterned into nanoribbons a bandgap can be introduced. By varying the width of these nanoribbons this band gap can be tuned from semiconducting to metallic. This property allows metallic and semiconducting regions within a single Graphene monolayer, which can be used in realising two-dimensional (2D) planar Metal-Insulator-Semiconductor field effect devices.

High-speed free-space based reconfigurable card-to-card optical interconnects with broadcast capability.

In this paper, we propose and experimentally demonstrate a free-space based high-speed reconfigurable card-to-card optical interconnect architecture with broadcast capability, which is required for control functionalities and efficient parallel computing applications. Experimental results show that 10 Gb/s data can be broadcast to all receiving channels for up to 30 cm with a worst-case receiver sensitivity better than -12.20 dBm.

Experimental demonstration of high-speed free-space reconfigurable card-to-card optical interconnects.

In this paper, we experimentally demonstrate a high-speed free-space reconfigurable card-to-card optical interconnect architecture employing MEMS-based steering mirror arrays for simple and efficient link selection. A printed-circuit-board (PCB) based interconnect module is developed and 3 × 10 Gb/s reconfigurable card-to-card optical interconnect with a bit-error-rate (BER) of ~10(-6) for up to 30 cm is realized using a 250 μm pitch-size micro-lens array. In addition, due to the usage of MEMS steering-mirrors, larger lenses can be employed at the receiver side for collecting stronger optical signal power to increase the achievable interconnect range or to improve the BER performance.

Methodologies for assessing the use-phase power consumption and greenhouse gas emissions of telecommunications network services.

Internet traffic has grown rapidly in recent years and is expected to continue to expand significantly over the next decade. Consequently, the resulting greenhouse gas (GHG) emissions of telecommunications service-supporting infrastructures have become an important issue. In this study, we develop a set of models for assessing the use-phase power consumption and carbon dioxide emissions of telecom network services to help telecom providers gain a better understanding of the GHG emissions associated with the energy required for their networks and services.

Experimental demonstration of 3×3 10 Gb/s reconfigurable free space optical card-to-card interconnects.

In this Letter, we propose and demonstrate the concept of a free space optics-based parallel high-speed reconfigurable card-to-card interconnect architecture employing microelectromechanical systems (MEMS)-based steering mirror arrays in conjunction with VCSEL and photodiode arrays. A bit-error rate of ∼10(-6) and a receiver sensitivity below -11.5 dBm are experimentally attained with a proof-of-concept 3×3 10 Gb/s reconfigurable card-to-card optical interconnect demonstrator.

Ultra-broadband indoor optical wireless communication system with multimode fiber.

In this paper we experimentally demonstrate an ultra-broadband indoor full-duplex WDM optical wireless communication system with multimode fiber. The multimode fiber is used because it is employed in most of the already installed in-building fiber distribution networks. Simultaneous error-free (BER<10(-9)) transmission of 4×12.

High-speed indoor optical wireless communication system with single channel imaging receiver.

In this paper we experimentally investigate a gigabit indoor optical wireless communication system with single channel imaging receiver. It is shown that the use of single channel imaging receiver rejects most of the background light. This single channel imaging receiver is composed of an imaging lens and a small photo-sensitive area photodiode attached on a 2-axis actuator.

Simplification of millimeter-wave radio-over-fiber system employing heterodyning of uncorrelated optical carriers and self-homodyning of RF signal at the receiver.

A simplified millimeter-wave (mm-wave) radio-over-fiber (RoF) system employing a combination of optical heterodyning in signal generation and radio frequency (RF) self-homodyning in data recovery process is proposed and demonstrated. Three variants of the system are considered in which two independent uncorrelated lasers with a frequency offset equal to the desired mm-wave carrier frequency are used to generate the transmitted signal. Uncorrelated phase noise in the resulting mm-wave signal after photodetection was overcome by using RF self-homodyning in the data recovery process.