High-speed Wireless Research Articles

High-Throughput and Low-Latency Digital Baseband Architecture for Energy-Efficient Wireless VR Systems

This paper presents a novel baseband architecture that supports high-speed wireless VR solutions using 60 GHz RF circuits. Based on the experimental observations by our previous 60 GHz transceiver circuits, the efficient baseband architecture is proposed to enhance the quality of transmission. To achieve a zero-latency transmission, we define an (106,920, 95,040) interleaved-BCH error-correction code (ECC), which removes iterative processing steps in the previous LDPC ECC standardized for the near-field wireless communication. Introducing the block-level interleaving, the proposed baseband processing successfully scatters the existing burst errors to the small-sized component codes, and recovers up to 1080 consecutive bit errors in a data frame of 106,920 bits. To support the high-speed wireless VR system, we also design the massive-parallel BCH encoder and decoder, which is tightly connected to the block-level interleaver and de-interleaver. Including the high-speed analog interfaces for the external devices, the proposed baseband architecture is designed in 65 nm CMOS, supporting a data rate of up to 12.8 Gbps. Experimental results show that the proposed wireless VR solution can transfer up to 4 K high-resolution video streams without using time-consuming compression and decompression, successfully achieving a transfer latency of 1 ms.

THz-to-optical conversion in wireless communications using an ultra-broadband plasmonic modulator

Future wireless communication networks will need to handle data rates of tens or even hundreds of Gbit s−1 per link, requiring carrier frequencies in the unallocated THz spectrum1,2. In this context, seamless integration of THz links into existing fibre-optic infrastructures3 is of great importance to complement the inherent portability and flexibility advantages of wireless networks and the reliable and virtually unlimited capacity of optical transmission systems. On the technological level, this requires novel device and signal processing concepts for direct conversion of data streams between the THz and optical domains. Here, we demonstrate a THz link that is seamlessly integrated into a fibre-optic network using direct THz-to-optical (T/O) conversion at the wireless receiver. We exploit an ultra-broadband silicon-plasmonic modulator having a 3 dB bandwidth in excess of 0.36 THz for T/O conversion of a 50 Gbit s−1 data stream that is transmitted on a 0.2885 THz carrier over a 16-m-long wireless link. Optical-to-THz (O/T) conversion at the wireless transmitter relies on photomixing in a uni-travelling-carrier photodiode. A high-speed wireless THz communication link is seamlessly integrated into a fibre-optic network. The demonstration relies on an ultra-broadband modulator exploiting two-dimensionally localized gap plasmons for direct conversion of the THz signals to the optical domain.

Giving Your Home an Edge [The Art of Storage

The Internet of Things and future high-speed wireless networks (such as 5G) are enabling the generation of more data in our homes and in the infrastructure around us than have been created during the entire history of humanity. This will lead to more communication and the use of cloud-based computing, networking, and storage resources [1]. Another impact is the growth of data at the edge of networks. This idea of the edge is rather nebulous; it could refer to computing, networking, and storage/memory at a 5G-enabled cell tower, and it might even describe a gateway and other networked devices in the home. Thus, your home could be at the edge of a network.

Design of a high-speed low-power wireless sensor node and verification for structural health monitoring

Design of a high-speed low-power wireless sensor node and verification for structural health monitoring

Max-Min Fair Resource Allocation in Millimetre-Wave Backhauls

5G mobile networks are expected to provide pervasive high speed wireless connectivity and support increasingly resource intensive user applications. Network hyper-densification therefore becomes necessary, though connecting to the Internet tens of thousands of base stations is non-trivial, especially in urban scenarios where optical fibre is difficult and costly to deploy. The millimetre wave (mm-wave) spectrum is a promising candidate for inexpensive multi-Gbps wireless backhauling, but exploiting this band for effective multi-hop data communications is challenging. In particular, resource allocation and scheduling of very narrow transmission/ reception beams require to overcome terminal deafness and link blockage problems, while managing fairness issues that arise when flows encounter dissimilar competition and traverse different numbers of links with heterogeneous quality. In this paper, we propose WiHaul, an airtime allocation and scheduling mechanism that overcomes these challenges specific to multi-hop mm-wave networks, guarantees max-min fairness among traffic flows, and ensures the overall available backhaul resources are fully utilised. We evaluate the proposed WiHaul scheme over a broad range of practical network conditions, and demonstrate up to 5× individual throughput gains and a five-fold improvement in terms of measurable fairness, over recent mm-wave scheduling solutions.

Fiber-Fed Distributed Antenna System in an FPGA Software Defined Radio for 5G Demonstration

The implementation of high-speed wireless networks, such as currently used fourth generation (4G) systems and future 5G systems, feature challenging processing. Field programmable gate arrays (FPGAs) can straddle research and development for these current and future networks since they provide scaling through reconfigurable logic, high parallelism, and low power consumption. This brief demonstrates an FPGA circuit implementation, with measurements, of a minimal system (a 5G element or “unit cell”): a single-user mobile with antenna diversity and a distributed antenna system (DAS) at the base station. The demonstration system has a bandwidth of 20 MHz, runs at 2.4 GHz, and has two antennas at both the transmitting base station and at the receiving mobile. The modulation is orthogonal frequency division multiplexing (OFDM) with space-time block coding (STBC). The FPGA is a Virtex-6, used for software defined radio (SDR), and this can readily be scaled to handle larger-dimensioned, higher-capacity systems. The receiver has time-offset synchronization, frequency-offset, and channel estimation. The high-level algorithm design (Xilinx System Generator) for these functions and the OFDM-STBC, and the resources consumed on the FPGA during real-time implementation, are included. We also compare the use of coax and fiber for linking the distributed antennas, using off-the-shelf components. The approach used here of combining simulations with physical measurement of a minimal system is a practical way forward for assessing candidate systems for 5G.

Cooperative Learning for Spectrum Management in Railway Cognitive Radio Network

High-speed rail public broadband wireless access requires communication terminals with high mobility to perform seamless cell switching in a harsh and fast time-varying environment. However, frequent switching caused by fast motion inevitably leads to unpredictable high volatility of the available spectrum, resulting in inefficient wireless communication. The application of highly mobile cognitive radio technology may address this challenge. This paper first analyzes the physical structure of the existing railway wireless communication network, and determines the characteristics of chainlike distribution and cascade operation of the base stations along the railway. Furthermore, using Bayesian reinforcement learning and multi-agent theory, a distributed cognitive base station model suitable for railway wireless environment is constructed. Based on the joint spectrum management of cascaded base station groups, this model proposes a multi-agent coordination algorithm with the goal of global optimal communication performance of the entire rail line. Finally, this paper evaluates the network performance of various test scenarios, and proves that the cognitive base station multi-agent cascade cooperative system can significantly increase the probability of successful data transmission and greatly reduce wireless spectrum handovers. This proposed scheme provides a brand-new solution for solving the problem of low wireless spectrum efficiency in the typical railway wireless network.

Evolution of Bridge Diagnostic Load Testing in the USA

Driven by advancements in technology, along with the ever-growing demands of our aging infrastructure, structural evaluation through testing has progressed from a number of research endeavors to a full-fledged industry. Guidelines for Non-Destructive Evaluation (NDE) methods, diagnostic load testing, and proof load testing were published by the American Association of State Highway and Transportation Officials (AASHTO) in 2003 and were largely shaped by the technologies that were available in the 1990s. While specifications in subsequent AASHTO bridge evaluation manuals have remained relatively constant over the last 15 years, commercial applications have sprung forth in all areas of field-based bridge assessment. Much of the development has revolved around inexpensive high-speed data acquisition, high-speed wireless communications, and the surge of cloud-based data management. The market of equipment and services has developed around three main camps; NDE, Controlled Load Testing, and Structural Health Monitoring (SHM), with each field having a variety of subcategories. For example, Diagnostic Load Tests and Proof Load Tests are the two primary forms of controlled load testing. Selection of the appropriate tools and methods to solve any bridge assessment is a function of what information is available and the required functional serviceability of the structure. In many cases, a combination of methods must be employed to achieve a complete assessment. As such, the lines between NDE, Testing, and SHM have blurred and have become increasingly integral gears of a larger machine. This article provides a history of the primary field bridge evaluation techniques and includes the driving forces in commercial development. Focus is placed primarily on diagnostic load test methodology; however, a variety of testing methods are outlined to illustrate the best tool for the job, along with the several pros and cons of various testing and monitoring methods. Finally, a glimpse into the future of bridge evaluation is provided based on current trends and emerging technologies.

Toward a flexible and adaptive wireless hub by embedding power amplifier thinned silicon chip and antenna in a polymer foil

AbstractA flexible and adaptive energy-efficient high-speed wireless hub is developed in polymer foil as a Hybrid System-in-Foil (HySiF) using Chip-Film Patch (CFP) technology. In this matter, the SiGe BiCMOS silicon chips (2.39 × 1.65 mm2) are thinned down to 45 μm and are embedded face-up inside a two-polymer CFP carrier. The active pads of the embedded silicon chips inside foil are extended to the surface of the foil to interconnect to the antenna on the foil. The integrated hybrid system has a signal transmission at 5–6 GHz frequency band. The overall thickness of the system is below 100 μm and its bendability is down to 4 mm radius of curvature. The designed and fabricated PA silicon chips operate at 50 mA with a 1.5 V supply voltage. Therefore, in addition to the high lateral thermal resistance of the thinned chip, self-heating loop inside polymer due to the low thermal conductivity of the embedding polymer raises the system temperature. Consequently, the thermal behavior and RF performance of the PA chip under different conditions are investigated. Moreover, the antenna with the required carrier frequency is simulated, fabricated, and measured on top of the polymer foil as a stand-alone system in the flexible CFP.

Special Issue on Recent Trends and Future of Fog and Edge Computing, Services and Enabling Technologies

Special Issue on Recent Trends and Future of Fog and Edge Computing, Services and Enabling Technologies

A 60-GHz 3.0-Gb/s Spectrum Efficient BPOOK Transceiver for Low-Power Short-Range Wireless in 65-nm CMOS

This paper presents a 60-GHz transceiver for low-power high-speed short-range wireless using the proposed binary-phase on-off keying (BPOOK) modulation scheme. The proposed BPOOK wireless transceiver transmits radio frequency (RF) signal with amplitude modulated on and off by input baseband data, and meanwhile, the phase is changing between 0° and 180°. The BPOOK transceiver achieves doubled spectral efficiency compared with OOK modulation and binary-phase-shift keying (BPSK) modulation. It also cancels the intrinsic local-oscillator feed through (LOFT) issue in the OOK modulation. The BPOOK RF signal can be demodulated by employing low-power square-law envelope detector incoherently. The transceiver is fabricated in a standard 65-nm CMOS technology. A data rate of 3.0 Gb/s is achieved while consuming a power of 100 mW from 1-V supply. The incoherent receiver has a sensitivity of −46 dBm. The core area of the transceiver is 1.56 mm2.

A Millimeter-Wave Partially Overlapped Beamforming-MIMO Receiver: Theory, Design, and Implementation

This paper presents an analysis and design of a partially overlapped beamforming-multiple-input multiple-output (MIMO) architecture capable of achieving higher beamforming and spatial multiplexing gains with lower number of elements compared to conventional architectures. As a proof of concept, a four-element beamforming-MIMO receiver (RX) covering 64-67-GHz frequency band (the FCC’s newly allocated 64–71-GHz frequency band for high-speed wireless links between small cells) enabling two-stream concurrent reception is designed and measured. By partitioning the RX elements into two clusters and partially overlapping these clusters to create two three-element beamformers, both phased array (coherent beamforming) as well as MIMO (spatial multiplexing) features are simultaneously acquired. 6-bit phase shifters with 360° phase control and 5-bit VGAs with 11-dB range are designed to enable steering of the two RX clusters toward two arbitrary angular locations corresponding to two users. Fabricated in a 130-nm SiGe BiCMOS process, the RX achieves a 30.15-dB maximum direct conversion gain and a 9.8-dB minimum noise figure across 548-MHz IF bandwidth. S-parameter-based array factor measurements verify spatial filtering of the interference and spatial multiplexing in this RX chip.

High-Gain Circularly Polarized Lens Antenna for Terahertz Applications

A high-gain circularly polarized (CP) lens antenna fed by a standard linearly polarized (LP) pyramidal horn operating at 300 GHz is proposed in this letter. The high-gain CP lens consists of discrete variable-height dielectric posts and grating. The height of each dielectric post is tuned to realize the required transmission phase, forming a planar wavefront above the lens aperture. By integrating the bottom dielectric grating with anisotropic characteristic, the dielectric lens can transform the incident LP waves from the feed source into CP radiation waves. Three-dimensional (3-D) printing technique is utilized to fabricate the terahertz (THz) CP lens for simplifying the fabrication process and reducing the cost. Measured results show that the designed lens can realize right-hand circular polarization radiation with a gain of 30.8 dBic at 300 GHz. The measured 1 dB gain bandwidth and 3 dB axial-ratio bandwidth of the THz CP lens can reach 13.3% and 18.8%, respectively. 3-D printed dielectric CP lens for use at THz frequencies is demonstrated, opening new possibilities for future high-speed wireless communications.

Extending Spatial and Temporal Characterization of Indoor Wireless Channels From 350 to 650 GHz

Communication at terahertz carrier frequencies is a promising way to satisfy the ever-growing demands for high-speed wireless networks. The studies of terahertz wireless channels have so far been limited to the atmospheric transmission bands below 350 GHz. Availability of high-power transmitters and high-sensitivity receivers at higher frequencies necessitates extending the wireless channel studies to enable higher data-rate communication systems. With a view to assessing communication system design requirements at higher frequencies, we present the channel measurement results for 650-GHz carrier frequencies in comparison with 350 GHz carrier frequencies in a typical indoor environment. To obtain the spatial and temporal characteristics of the channel, the power angle profile and the power delay profile are measured based on new measurement methods. Multiple spatially resolvable paths are observed at both 350- and 650-GHz carrier frequencies. Signal-to-noise ratio of the received signal through the non-line-of-sight (NLoS) paths is sufficiently high to enable robust communication when the direct line-of-sight (LoS) path is blocked due to a moving object. The measurement results are used to calculate the reduction in the 650-GHz channel capacity in comparison with that of the 350-GHz channel for both LoS and NLoS paths. Channel dispersion characterization over a 10-GHz bandwidth shows that the delay spreads for the resolved LoS and NLoS paths are less than 80 ps for both 350- and 650-GHz bands. Therefore, no complicated equalizer is required to compensate for channel dispersion at both 350 and 650-GHz, which greatly simplifies the terahertz transceiver design.

Spatial Continuous Wave Laser and Spatiotemporal VCSEL for High-Speed Long Haul Optical Wireless Communication Channels

Abstract This study has presented spatial continuous wave laser and spatiotemporal vertical cavity surface emitting laser (VCSEL) for high speed long haul optical wireless communication channels. Possible data rates range from 40 Gb/s to 250 Gb/s over propagation distance ranges from 500 km to 2500 km. The optical wireless communication (OWC) system performance is tested through the measurement of maximum Q-factor, minimum bit error rate (BER) and signal to noise ratio (SNR). It is observed that spatiotemporal VCSEL has presented better performance than CW laser in the OWC system, especially for long haul transmission applications. It is observed that SNR improvement ratio ranges from 8.15 % to 19 % by using spatiotemporal VCSEL than CW laser for bit rate of 40 Gb/s over propagation distance ranges from 500 km to 2500 km. Max. Q-factor improvement ratio ranges from 4.62 % to 13.71 % by using spatiotemporal VCSEL than CW laser for data rate of 40 Gb/s over propagation distance ranges from 500 km to 2500 km. So it is clear that spatiotemporal VCSEL is more suitable for long haul OWC applications than other optical sources.

Measurements and analysis of vehicular radio channels in the inland lake bridge area

Vehicular communication plays a vital role in intelligent transportation systems and smart cities. The huge data transmission and high mobility require a high-speed and stable wireless channel as a basis. This study presents a 5.9 GHz vehicle-to-vehicle (V2V) measurement, covering a complete inland lake bridge communication environment. Analysis of the channel characteristics is carried out according to three main propagation scenarios: ramp merging, a rear vehicle overtaking the front vehicle, and an urban scenario. Channel characteristics including the power delay profile, Doppler spectral density, amplitude distribution, and fading depth (FD) is extracted and analysed. An FD of ∼2.5 dB is determined in V2V communication. Furthermore, it is observed that, in addition to the impact from the ramp structure, metallic traffic signs, road lights, pedestrian bridges, and large trucks can also make significant contributions to vehicular communication. Moreover, a triple Gaussian mixture distribution is proposed to model the channel characterisation. The results demonstrate that the specific structure of the ramp will influence the channel performance more significantly than the general traffic road structure, which can provide a meaningful reference for the future research of V2V radio channels and is useful for the design and layout of vehicular communication systems.

Sub-THz Antenna for High-Speed Wireless Communication Systems

Terahertz (THz) links will play a major role in high data rate communication over a distance of few meters. In order to achieve this task, antenna designs with high gain and wideband characteristics will spearhead these links. In this contribution, we present different antenna designs that offer characteristics better suited to THz communication over short distances. Firstly, a single-element antenna having a dipole and reflector is designed to operate at 300 GHz, which is considered as a sub-terahertz band. That antenna achieves a wide impedance bandwidth of 38.6% from 294 GHz to 410 GHz with a gain of 5.14 dBi. Secondly, two designs based on the same dipole structure but with added directors are introduced to increase the gain while maintaining almost the same bandwidth. The gains achieved are 8.01 dBi and 9.6 dBi, respectively. Finally, an array of 1×4 elements is used to achieve the highest possible gain of 13.6 dBi with good efficiency about 89% and with limited director elements for a planar compact structure to state-of-the-art literature. All the results achieved make the proposed designs viable candidates for high-speed and short-distance wireless communication systems.

Integrated Millimeter Wave and Sub-6 GHz Wireless Networks: A Roadmap for Joint Mobile Broadband and Ultra-Reliable Low-Latency Communications

Next-generation wireless networks must enable emerging technologies such as augmented reality and connected autonomous vehicles via a wide range of wireless services that span enhanced mobile broadband (eMBB) and ultra-reliable low-latency communication (URLLC). Existing wireless systems that solely rely on the scarce sub-6 GHz, mW frequency bands will be unable to meet such stringent and mixed service requirements for future wireless services due to spectrum scarcity. Meanwhile, operating at high-frequency mmWave bands is seen as an attractive solution, primarily due to the bandwidth availability and possibility of large-scale multi-antenna communication. However, even though leveraging the large bandwidth at mmWave frequencies can potentially boost the wireless capacity for eMBB services and reduce the transmission delay for low-latency applications, mmWave communication is inherently unreliable due to its susceptibility to blockage, high path loss, and channel uncertainty. Hence, to provide URLLC and high-speed wireless access, it is desirable to seamlessly integrate the reliability of mW networks with the high capacity of mmWave networks. To this end, in this article, the first comprehensive tutorial for integrated mmWave-mW communications is introduced. This envisioned integrated design will enable wireless networks to achieve URLLC along with eMBB by leveraging the best of two worlds: reliable, long-range communications at the mW bands and directional high-speed communications at the mmWave frequencies. To achieve this goal, key solution concepts are discussed that include new architectures for the radio interface, URLLC-aware frame structure and resource allocation methods along with mobility management, to realize the potential of integrated mmWave-mW communications. The opportunities and challenges of each proposed scheme are discussed and key results are presented to show the merits of t

Alleviation of Thermal Instability via Novel Collector-Up HBTs for Reliable Wireless Applications

We analyzed thermal characteristics of power transistors based on the complementary InGaP/InGaAs/GaAs collector-up heterojunction bipolar transistors (HBTs), and especially for stable wireless applications under extreme operations. A newly developed structure, incorporating the graded InGaAs base and the nonuniform collector, without employing additional thermal-removal design is presented. Significantly, the multi-finger devices achieved compelling high speed and heat dissipation. Results show that the fairly matched high-frequency performance has been exhibited and over 30% improvement in the surface-temperature-rise ratio is achieved. As a consequence of the effective alleviation of unstable feedback phenomena by this novel arrangement, exploiting the advantageous characteristics of complementary collector-up HBTs for thermally reliable high-speed wireless applications is feasible.

Computational entrepreneurship: from economic complexities to interdisciplinary research

The development of technology is unbelievably rapid. From limited local networks to high speed Internet, from crude computing machines to powerful semi-conductors, the world had changed drastically compared to just a few decades ago. In the constantly renewing process of adapting to such an unnaturally high-entropy setting, innovations as well as entirely new concepts, were often born. In the business world, one such phenomenon was the creation of a new type of entrepreneurship. This paper proposes a new academic discipline of computational entrepreneurship, which centers on: (i) an exponentially growing (and less expensive) computing power, to the extent that almost everybody in a modern society can own and use that; (ii) omnipresent high-speed Internet connectivity, wired or wireless, representing our modern day’s economic connectomics; (iii) growing concern of exploiting “serendipity” for a strategic commercial advantage; and (iv) growing capabilities of lay people in performing calculations for their informed decisions in taking fast-moving entrepreneurial opportunities. Computational entrepreneurship has slowly become a new mode of operation for business ventures and will likely bring the academic discipline of entrepreneurship back to mainstream economics.