GHz MMW Research Articles

60 GHz MMW sensor for monitoring driver’s vital signs

Many fatal traffic accidents caused by professional drivers are attributed not only to fatigue and stress, but also heart and cardiovascular disease. Heartbeat interval (HBI) is one of the primary vital signs that indicates a sudden change in a person’s physical condition. In addition, blood pressure, particularly continuous blood pressure (BP), is highly correlated with cardiovascular disease. However, to our knowledge, there are no studies on monitoring a driver’s HBI and continuous BP simultaneously. In this paper, we present a 60 GHz millimeter-wave vital signs sensor to monitor the driver’s HBI and continuous BP in a non-contact manner. The driver’s HBI and continuous BP were measured while driving and each measured vital sign was evaluated using correlation and Bland-Altman analysis.

Photonics-Assisted Millimeter-Wave Communication System Based on Low-Bit Gaussian Mixture Model Adaptive Vector Quantization

The quantization technique with a low-bit resolution can significantly reduce the cost and power consumption of analog-to-digital converter (ADC). It will play an important role in energy conservation and cost reduction for the incoming B5G millimeter-wave (MMW) communication systems. In this paper, we propose and demonstrated experimentally a low-bit Gaussian mixture model (GMM) based non-uniform adaptive vector quantization (AVQ) scheme for the low-cost intensity modulated envelope detection photonics-assisted 28 GHz MMW communication system for the first time. The principles of GMM-based one-dimensional adaptive scalar quantization (ASQ) and multi-dimensional AVQ are first introduced, and then are used to realize the low-bit non-uniform adaptive quantization for reducing the ADC bit resolution of MMW receiver. Furthermore, the performance of traditional uniform quantization, the present <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> -means and proposed GMM-based non-uniform ASQ/AVQ schemes are evaluated and compared in detail. Utilizing the proposed GMM-based AVQ scheme, the ADC quantization resolution in our MMW receiver can be reduced from 5 bits of the traditional uniform quantization to as low as 2 bits, without noticeable performance penalty. Moreover, as compared with the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> -means-based quantization scheme, the MMW receiver enabled by GMM-based ASQ/AVQ scheme can save about half of the quantization time under similar performance. This is mainly because the clustering based on probability converges faster than the Euclidean distance, which significantly reduces the number of iterations required. Therefore, the GMM-based AVQ scheme is a promising solution to realize high performance ADCs with low-bit resolution for future MMW-enabled optical fiber wireless access networks.

Quantum-Dash Laser-Based Tunable 50/75 GHz mmW Transport System for Future L-Band Networks

Tunable 50/75 GHz millimeter wave (mmW) transmission system has been demonstrated employing self-injection locked quantum-dash laser diode comb source (SIL QDCS) in the challenging 1610 nm region. The generated 50/75 GHz mmW beat-tones exhibited low phase noise of −64 dB/Hz at 1 kHz offset and narrow radio-frequency (RF) linewidths of ~1 kHz at the transmitter end. A 4 GBd (8 Gb/s) quadrature phase-shift keying (QPSK) data stream is successfully transmitted over both mmW carriers and across various channels <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">viz. 2</i> m wireless (WL) link, 11.6 km single-mode-fiber (SMF) – 2 m WL link, and 11.6 km SMF – 6 m free-space-optics (FSO) – 2 m WL link, thus affirming the potential of quantum-dash laser diode (QDLD) in high-frequency mmW applications. This work is a potential step towards realizing next-generation high-frequency tunable mmW optical-RF convergent hybrid networks operation in L-band, and one such possible proposal with a single QDCS is presented.

Towards InAs/InP Quantum-Dash Laser-Based Ultra-High Capacity Heterogeneous Optical Networks: A Review

The unprecedented increase in internet traffic witnessed in the last few years has pushed the community to explore heterogeneous optical networks, including free-space-optics (FSO) communication, radio-over-fiber (RoF), wireless (WL), and their convergent hybrid technologies. This stems from the possibility of seamless integration with the existing fiber-optic backhaul networks while providing much-needed flexibility and scalability. Moreover, efficient optical transceivers, particularly light sources in the form of semiconductor laser diodes, are key in meeting the future demands of the next generation green optical access networks. In this respect, InAs/InP Quantum-dash (Qdash) nanostructure-based lasers have shown tremendous progress in the past few years with applications spanning from a wavelength division multiplexed (WDM) optical communication to recently, millimeter-wave (MMW) over fiber networks. This waveguide-based laser diode (LD) has demonstrated a rule-changing broad multi-wavelength lasing emission, thanks to the inherent and wavelength-tunable wide gain profile offered by the Qdash active-gain region covering S- to U-band regions. Moreover, exploiting mode-locking and optical injection locking assisting techniques, highly coherent InAs/InP Qdash comb laser source at 1550 nm and 1610 nm have been respectively realized, thus opening a new paradigm for their potential applications in green optical and 5G access networks. In this work, progress on utilizing InAs/InP Qdash LD, supporting several sub-carriers, in energy-efficient ~1550 nm and ~1610 nm WDM heterogeneous optical networks with single-mode-fibers (SMF) has been highlighted, exhibiting aggregate data rates of 11 – 12 Tb/s by employing a single device, and accommodating PAM4 and higher-order 32-QAM modulation schemes. Moreover, the recent deployment of this LD in the RoF domain, targeting MMW frequency band, for convergent fiber-wireless networks, is also summarized, with demonstrated 25 to >100 GHz MMW beat-tone frequency generates and transmission of up to 24 Gb/s.

Self-referenced distribution of millimeter waves over 10 km optical fiber with high frequency stability.

In this Letter, an actively stabilized photonic system for millimeter-wave (mmW) signal distribution is proposed and experimentally demonstrated. By interlocking two baseband RF signals obtained from a dual-heterodyne detection through a single carrier compensation module, the phase fluctuations induced by the fiber transmission link is suppressed without the need of a local frequency reference. In the proof-of-concept experiment, a 108 GHz mmW is transmitted over a 10 km fiber link with a performance matching that of the back-to-back case. The feedback system reduces the phase noise of the delivered mmW signal by 37 dB and 28 dB at 0.1 Hz and 1 Hz frequency offset, respectively, and the long-term stability is improved by nearly two orders of magnitude.

Non-Ionizing Millimeter Waves Non-Thermal Radiation of Saccharomyces cerevisiae—Insights and Interactions

Non-ionizing millimeter-waves (MMW) interact with cells in a variety of ways. Here the inhibited cell division effect was investigated using 85–105 GHz MMW irradiation within the International Commission on Non-Ionizing Radiation Protection (ICNIRP) non-thermal 20 mW/cm2 safety standards. Irradiation using a power density of about 1.0 mW/cm2 SAR over 5–6 h on 50 cells/μL samples of Saccharomyces cerevisiae model organism resulted in 62% growth rate reduction compared to the control (sham). The effect was specific for 85–105 GHz range and was energy- and cell density-dependent. Irradiation of wild type and Δrad52 (DNA damage repair gene) deleted cells presented no differences of colony growth profiles indicating non-thermal MMW treatment does not cause permanent genetic alterations. Dose versus response relations studied using a standard horn antenna (~1.0 mW/cm2) and compared to that of a compact waveguide (17.17 mW/cm2) for increased power delivery resulted in complete termination of cell division via non-thermal processes supported by temperature rise measurements. We have shown that non-thermal MMW radiation has potential for future use in treatment of yeast related diseases and other targeted biomedical outcomes.

Hybrid 28 GHz MMW over fiber-wireless QPSK transmission system based on mid L-band external injection-locked quantum-dash laser comb source

We report on the generation and transmission of millimeter-wave (MMW) beat-tone at 28 GHz from an external injection-locked InAs/InP quantum-dash laser-based comb source emitting in mid L-band. The MMW beat-tone exhibited a narrow linewidth, and low phase noise of ~ −122 dBc/Hz at 1.0 MHz offset frequency, thus demonstrating superior characteristics. Thereafter, we achieved a successful transmission of 2 Gbps quadrature-phase-shift-keying (QPSK) signal over 28 GHz MMW beat-tone carrier on 4 m wireless channel as well as 20 km single-mode fiber and 4 m wireless hybrid channel, exhibiting receiver sensitivities of −1.0 and −0.5 dBm, respectively. This demonstration paves the way for the potential deployment of this new-class of MMW photonic source in future passive optical networks and 5G, enabling exploiting hybrid architectures and extended L-band wavelength operation besides the conventional C-band.

Low phase noise and quasi-tunable millimeter-wave generator using a passively InAs/InP mode-locked quantum dot laser

A low phase noise millimeter-wave (MMW) signal generator is proposed and experimentally demonstrated with a C-band passively Fabry-Perot (F-P) quantum dot mode-locked laser. A novel method is proposed to generate low phase noise MMW signal, which is simply based on a commercial off-the-shelf dual-driven LiNbO3 Mach-Zehnder modulator and a passively F-P quantum dot mode-locked laser. MMW signal with the frequency of 30 GHz, 45 GHz and 90 GHz respectively is obtained experimentally. Single-sideband phase noise of the 30 GHz and 45 GHz MMW signal is −112 dBc/Hz and −106 dBc/Hz at an offset of 1 kHz, respectively. The linewidth of the 30 GHz and 45 GHz MMW signal is about from 225 Hz and 239 Hz. This is considered a very simple MMW generator with a quasi-tunable broadband and ultra-low phase noise.

A 2-D Radon Transformation for Enhancing the Detection and Imaging of Embedded Defects in Layered Composite Structures Using Millimeter-Wave System

This paper aims to tackle the challenge of detecting the presence of embedded defects in layered composite structures using imaging techniques including a 2D Radon transformation. The proposed technique aims at enhancing the detection and imaging of embedded defects in layered composite structures that is captured using a millimeterwave (MMW) radar system. A 94 GHz MMW system is used in the near field to detect defects such as disbond and delamination embedded in complex glass fiber composite structures. In order to simplify the detection in glass fibers, measurement data attained using a MMW radar are plotted as images using MATLAB. A stable detection and identification of these defects from the collected images is proposed using a robust two-stage algorithm. The Weiner filter-based deconvolution technique is used for the reflectivity deconstruction in the image and a two-dimensional Radon transformation called back-projection is used to as an additional filtering step enhance the detection of the embedded defects. The proposed method allows defects that are embedded 24mm below the surface of the scanning probe to be detected and identified in terms of location. Our results show potential in the proposed method to be employed in accurately imaging defects in composites that are used in the aerospace and civil infrastructure industries.

Generation of 40 GHz/80 GHz OFDM based MMW source and the OFDM-FSO transport system based on special fine tracking technology

Abstract We have experimentally proposed and demonstrated a hybrid OFDM based optical MMW source and OFDM-FSO transport system employing special fine tracking technology. In this paper, 10 Gbps/40 GHz and 10 Gbps/80 GHz MMW source are successfully transmitted over 50-km and 25-km SMF as well as 20-m wireless link by employing variable length single mode fiber. 10 Gbps base band signal is successfully transmitted over 500-m FSO link with the assistance of special tracking and pointing technology. A position sensitive detector (PSD) is used in a fine tracking system, due to its much greater detection ability as compared to the conventional charge coupled device (CCD). Greater position resolution and high sensibility of PSD helps to communicate our signal over 500-m optical link. The limitation of dispersion and ISI effect in our wireless network are combat by employing appropriate length of cyclic prefix (CP) in our OFDM system. Here, we study the BER performance of the system by varying the length of CP. The proper length of CP boosts the system capacity and enhances the overall system performance. Low BER, good EVM (~ 12 % ), clear constellation diagrams proved the reliability and feasibility of our system as a prominent solution for multiservice wireless network.

Simple Multi-RAT RoF System With $2\times2$ MIMO Wireless Transmission

A simple multi-radio access technology (multi-RAT) capable radio over fiber (RoF) system with 2 × 2 multiple-inputmultiple-output (MIMO) wireless transmission is proposed and experimentally demonstrated. The transmission of sub-6 GHz and 60 GHz millimeter-wave (MMW) services is enabled by a dual-drive Mach-Zehnder modulator (DDMZM) and an optical interleaver. In the central office (CO), sub-6 GHz and 30 GHz signals are applied to the dual branches of the DDMZM which is biased at the quadrature point. After transmission over singlemode fiber (SMF), the two services are separated by the optical interleaver. One output port of the interleaver is used for delivering the sub-6 GHz signal while the other one is used for the generation and transmission of the 60 GHz MMW signal. Furthermore, we also demonstrate the MIMO technology can be used in the proposed architecture to improve the capacity. A proofof-concept experiment is performed to verify the feasibility of the proposed scheme. In the experiment, a 1.3 Gb/s orthogonal frequency division multiplexing (OFDM) signal at 55 GHz is transmitted over 25 km of SMF and 1 m 2 × 2 MIMO wireless distance while a 675 Mb/s OFDM signal at 0.375 GHz is delivered over 25 km of SMF at the same time.

Statistical Blockage Modeling and Robustness of Beamforming in Millimeter-Wave Systems

There has been a growing interest in the commercialization of millimeter wave (mmW) technology as a part of the Fifth-Generation New Radio (5G-NR) wireless standardization efforts. In this direction, many sets of independent measurement campaigns show that wireless propagation at mmW carrier frequencies is only marginally worse than propagation at sub-6 GHz carrier frequencies for small-cell coverage --- one of the most important use-cases for 5G-NR. On the other hand, the biggest determinants of viability of mmW systems in practice are penetration and blockage of mmW signals through different materials in the scattering environment. With this background, the focus of this paper is on understanding the impact of blockage of mmW signals and reduced spatial coverage due to penetration through the human hand, body, vehicles, etc. Leveraging measurements with a 28 GHz mmW experimental prototype and electromagnetic simulation studies, we first propose statistical blockage models to capture the impact of the hand, human body and vehicles. We then study the time-scales at which mmW signals are disrupted by blockage (hand and human body). Our results show that these events can be attributed to physical movements and the time-scales corresponding to blockage are hence on the order of a few 100 ms or more. Building on this fundamental understanding, we finally consider the broader question of robustness of mmW beamforming to handle blockage. Network densification, subarray switching in a user equipment (UE) designed with multiple subarrays, fall back mechanisms such as codebook enhancements and switching to legacy carriers in non-standalone deployments, etc. can address blockage before it leads to a deleterious impact on the mmW link margin.

Utilizing Single Lightwave for Delivering Baseband/FSO/MMW Traffics Simultaneously in PON Architecture

In this work, we demonstrate an integrated optical baseband, free space optical (FSO) communication and millimeter-wave (MMW) traffics through the present passive optical network (PON) architecture by utilizing single wavelength for broadcasting triple-play services. In the execution, we exploit 10 Gbit/s on-off keying (OOK) modulation on 10 GHz Mach-Zehnder modulator (MZM) to produce the downstream baseband signal. And the 10 Gbit/s baseband signal also can cause FSO traffic within the forward error correction (FEC) target after 25 km fiber and 160 m free space transmissions. Moreover, we can utilize the fiber to the extension (FTTE) scheme to provide the 36.42 GHz MMW with 10 Gbit/s OOK data after 25 km fiber link and 8 km extended fiber transmission.

A full-duplex WDM hybrid fiber-wired/fiber-wireless/fiber-VLC/fiber-IVLC transmission system based on a self-injection locked quantum dash laser and a RSOA

An advanced low cost bidirectional wavelength-division-multiplexing hybrid fiber-wired/fiber-wireless/fiber-VLC/fiber-IVLC transmission system based on a self-seeded InP based quantum dash-laser diode (QD-LD) and reflective semiconductor amplifier (RSOA) is proposed and experimentally demonstrated. In this paper, 10 Gbps/50 GHz MMW and 10 Gbps/100 GHz MMW over 50-km SMF as well as 40-m optical and 10-m radio-frequency (RF) wireless link, and 10 Gbps baseband (BB) data stream over 50-km SMF are successfully transmitted by employing self-injection locking scheme on QD-LD in downlink. RSOA is utilized at the receiving site to broadcast 2.5 Gbps data signal over 50-km SMF plus 10-m free-space link in uplink by reusing the carrier, that makes the system cost-effective. High receiver sensitivity and signal-to-noise ratio (SNR), low bit-error-rate (BER) and low error vector magnitude (EVM), and excellent eye-diagrams in our proposed network build the system more reliable and stable with acceptable performance. Therefore, proposed hybrid transmission system could become prominent alternative not only for progressive fiber backbone network but also for RF/optical wireless feeder networks.

Simulation and analysis of 60 GHz MMW for localisation based on machine learning

The 60 GHz pulse is more practical for the indoor localisation system due to its better time resolution. Usually, time-of-arrival (TOA) estimation with higher accuracy is critical to the indoor localisation. To acquire precise TOA estimations, a novel threshold crossing technique using neural network (NN) is discussed via analysing the characteristics of the received pulses based on the energy detection receiver. The relationship between the optimum thresholds and the signal-to-noise ratios (SNRs) are researched. Meanwhile, the influences caused by changing integration periods and channel models are examined. Results show that the proposed NN method can provide better accuracy and robustness to the lower SNR in the models designed by TG 3c.

O2 Thermal sensation threshold (TST) when exposed to millimeter waves (MMWS) in japanese

Objectives The millimeter-wave usage have recently expanded in our daily life, such as automobile collision avoidance radar system, airport active scanner system, WiGig, and so on. Thermal sensation induced by the millimeter-wave EMF exposure has not been fully studied. For the millimeter-wave guideline, we need objective data of the sensation threshold to millimeter waves. Methods This study was approved by the ethical committee of FMU and supported by the fund from the Ministry of Internal Affairs and Communications, Japan. TST to MMW was measured in 30 Japanese healthy adult volunteers. 95 GHz or 40 GHz MMWs were exposed to the palm of over three different sized exposed area more than 20 times. The subjects pressed a response button when she/he felt some sensation in each trial. We estimated the threshold evoking thermal sensation with three duration of exposure at 50% probability using two-dimensional cumulative distribution function and the maximum likelihood method. Results In both 95 GHz and 40 GHz MMW exposures, the longer the stimulation duration, or the larger the exposed area, the lower was TST. These non-linear relations of TST with the duration and area size of MMW stimulation are compatible with those of previous studies. Discussion Our present results support that our measurement method is reliable for TST measurement, and we are now measuring TSTs to 40 GHz in normal, male and female normal volunteers with different ages. Conclusions Normal values of TST to MMWs for the Japanese person will be established in this study. Significance The results was useful to establish the guideline for the MMWs in Japan.

Fiber-wireless integrated mobile backhaul network based on a hybrid millimeter-wave and free-space-optics architecture with an adaptive diversity combining technique.

We propose and experimentally demonstrate a novel fiber-wireless integrated mobile backhaul network based on a hybrid millimeter-wave (MMW) and free-space-optics (FSO) architecture using an adaptive combining technique. Both 60 GHz MMW and FSO links are demonstrated and fully integrated with optical fibers in a scalable and cost-effective backhaul system setup. Joint signal processing with an adaptive diversity combining technique (ADCT) is utilized at the receiver side based on a maximum ratio combining algorithm. Mobile backhaul transportation of 4-Gb/s 16 quadrature amplitude modulation frequency-division multiplexing (QAM-OFDM) data is experimentally demonstrated and tested under various weather conditions synthesized in the lab. Performance improvement in terms of reduced error vector magnitude (EVM) and enhanced link reliability are validated under fog, rain, and turbulence conditions.

Performance evaluation of TOA estimation for 60 GHz MMW system based on IEEE 802.15.3c channel model

Performance evaluation of TOA estimation for 60 GHz MMW system based on IEEE 802.15.3c channel model

A Bidirectional Wireless-Over-Fiber Transport System

This study proposes and demonstrates a bidirectional wireless-over-fiber (WoF) transport system based on an optical interleaver, a phase modulator, and an optical bandpass filter (OBPF)-based phase-modulation-to-intensity-modulation converter that can deliver intensity-modulated 60 GHz millimeter-wave (MMW), 30 GHz microwave (MW), and phase-remodulated 15 GHz MW data signals. A broadband light source, comprising an optoelectronic oscillator scheme and an optical signal-to-noise ratio (OSNR) enhancement scheme, is deployed in these bidirectional 60 GHz/30 GHz/15 GHz WoF transport systems. For downlink transmission, light is promoted optically from a 5 Gbps/ 15 GHz MW data signal to 5 Gbps/60 GHz MMW and 5 Gbps/30 GHz MW data signals in fiber-wireless convergence. The downstream light is phase remodulated successfully using a 5 Gbps/15 GHz MW data signal for uplink transmission. Through a thorough examination of such bidirectional 60 GHz/30 GHz/15 GHz WoF transport systems, the bit error rate (BER) is observed to perform well over a 40 km single-mode fiber and a 4 m RF wireless transmission. This bidirectional 60 GHz/30 GHz/15 GHz WoF transport system is a prominent alternative not only because of its advancement in integrating optical fiber and RF wireless networks but because of the benefits of communication links for broader bandwidth and higher transmission rate as well.

Hybrid CATV/MMW/BB lightwave transmission system based on fiber-wired/fiber-wireless/fiber-VLLC integrations.

A hybrid lightwave transmission system for cable television (CATV)/millimeter-wave (MMW)/baseband (BB) signal transmission based on fiber-wired/fiber-wireless/fiber-visible laser light communication (VLLC) integrations is proposed and demonstrated. For down-link transmission, the light is intensity-modulated with 50-550 MHz CATV signal and optically promoted from 25 GHz radio frequency (RF) signal to 10 Gbps/50 GHz and 20 Gbps/100 GHz MMW data signals based on fiber-wired and fiber-wireless integrations. Good performances of carrier-to-noise ratio (CNR), composite second-order (CSO), composite triple-beat (CTB), and bit error rate (BER) are obtained over a 40-km single-mode fiber (SMF) and a 10-m RF wireless transport. For up-link transmission, the light is successfully intensity-remodulated with 5-Gbps BB data stream based on fiber-VLLC integration. Good BER performance is achieved over a 40-km SMF and a 10-m free-space VLLC transport. Such a hybrid CATV/MMW/BB lightwave transmission system is an attractive alternative, it gives the benefits of a communication link for broader bandwidth and higher transmission rate.