Wireless Chip Research Articles

AI-Enhanced Distance Estimation via Radio Chip Link Quality Metrics and Time-of-Flight Analysis With UWB Technology: A Comparative Evaluation

AI-Enhanced Distance Estimation via Radio Chip Link Quality Metrics and Time-of-Flight Analysis With UWB Technology: A Comparative Evaluation

Internet of Things-Enabled Patch With Built-in Microsensors and Wireless Chip: Real-Time Remote Monitoring of Patch Treatment.

We aimed to design, develop, and evaluate an internet of things-enabled patch (IoT patch) for real-time remote monitoring of adherence (or patch wear time) during patch treatment in child participants in clinical trials. This study provides healthcare providers with a tool for objective, real-time, and remote assessment of adherence and for making required adjustments to treatment plans. The IoT patch had two temperature microsensors and a wireless chip. One sensor was placed closer to the skin than the other, resulting in a temperature difference depending on whether the patch was worn. When the patch was worn, it measured temperatures every 30 seconds and transmitted temperature data to a cloud server via a mobile application every 15 seconds. The patch was evaluated via 2 experiments with 30 healthy adults and 40 children with amblyopia. Excellent monitoring accuracy was observed in both adults (mean delay of recorded time data, 0.4 minutes) and children (mean, 0.5 minutes). The difference between manually recorded and objectively recorded patch wear times showed good agreement in both groups. Experiment 1 showed accurate monitoring over a wide range of temperatures (from 0 to 30°C). Experiment 2 showed no significant differences in wearability (ease-of-use and comfort scores) between the IoT and conventional patches. The IoT patch offers an accurate, real-time, and remote system to monitor adherence to patch treatment. The patch is comfortable and easy to use. The utilization of an IoT patch may increase adherence to patch treatment based on accurate monitoring. Results show that the IoT patch can enable real-time adherence monitoring in clinical trials, improving treatment precision, and patient compliance to enhance outcomes.

Tumor therapeutic response monitored by telemetric temperature sensing, a preclinical study on immunotherapy and chemotherapy

Temperature in the body and the tumor reflects physiological and pathological conditions. A reliable, contactless, and simplistic measurement system can be used for long-term monitoring of disease progression and therapy response. In this study, miniaturized battery-free wireless chips implanted into growing tumors on small animals were used to capture both basal and tumor temperature dynamics. Three preclinical models: melanoma (B16), breast cancer (4T1), and colon cancer (MC-38), were treated with adoptive T cell transfer, AC-T chemotherapy, and anti-PD-1 immunotherapy respectively. Each model presents a distinctive pattern of temperature history dependent on the tumor characteristic and influenced by the administered therapy. Certain features are associated with positive therapeutic response, for instance the transient reduction of body and tumor temperature following adaptive T cell transfer, the elevation of tumor temperature following chemotherapy, and a steady decline of body temperature following anti-PD-1 therapy. Tracking in vivo thermal activity by cost-effective telemetric sensing has the potential of offering earlier treatment assessment to patients without requiring complex imaging or lab testing. Multi-parametric on-demand monitoring of tumor microenvironment by permanent implants and its integration into health information systems could further advance cancer management and reduce patient burden.

MEMS piezoelectric resonant microphone array for lung sound classification

This paper reports a highly sensitive piezoelectric microelectromechanical systems (MEMS) resonant microphone array (RMA) for detection and classification of wheezing in lung sounds. The RMA is composed of eight width-stepped cantilever resonant microphones with Mel-distributed resonance frequencies from 230 to 630 Hz, the main frequency range of wheezing. At the resonance frequencies, the unamplified sensitivities of the microphones in the RMA are between 86 and 265 mV Pa−1, while the signal-to-noise ratios (SNRs) for 1 Pa sound pressure are between 86.6 and 98.0 dBA. Over 200–650 Hz, the unamplified sensitivities are between 35 and 265 mV Pa−1, while the SNRs are between 79 and 98 dBA. Wheezing feature in lung sounds recorded by the RMA is more distinguishable than that recorded by a reference microphone with traditional flat sensitivity, and thus, the automatic classification accuracy of wheezing is higher with the lung sounds recorded by the RMA than with those by the reference microphone, when tested with deep learning algorithms on computer or with simple machine learning algorithms on low-power wireless chip set for wearable applications.

Wigner distribution function approach to analyze MIMO communication within a waveguide

Multiple-input-multiple-output (MIMO) communication is a technology to create high capacity wireless links. The main aim of this paper is to provide a foundation to mathematically model wireless chip to chip communication within complex enclosures. This paper mainly concentrates on modelling wave propagation between transmit and receive antennas through a phase space approach which exploits the relationship between the field-field correlation function (CF) and the Wigner distribution function (WDF). A reliable model of wireless chip-to-chip (C2C) communication helps mitigate the information bottleneck caused due to the wired connections between chips, thus, help improve the efficiency of electronic devices of the future. Placing complex sources such as printed circuit board (PCB) inside a cavity or enclosure results in multi-path interference and hence makes the prediction of signal propagation more difficult. Thus, the CFs can be propagated based on a ray transport approach that predicts the average radiated density, but not the significant fluctuations that occur about it. Hence, the WDF approach can be extended to problems in finite cavities that incorporates reflections as well. Phase space propagators based on classical multi-reflection ray dynamics can be obtained by considering the high-frequency asymptotics.

Exploiting Ultra-Wideband Channel Impulse Responses for Device-Free Localization.

In radio-frequency (RF)-based device-free localization (DFL), the number of sensors acting as RF transmitters and receivers is crucial for accuracy and system costs. Two promising approaches for DFL have been identified in the past: radio tomographic imaging (RTI) and multi-static radar (MSR). RTI in its basic version requires many sensors for high accuracy, which increases the cost. In this paper, we show how RTI benefits from multipath propagation. By evaluating the direct and echo paths, we increase the coverage of the target area, and by utilizing UWB signals, the RTI system is less susceptible to multipath propagation. MSR maps reflections that occur within the target area to reflectors such as persons or other objects. MSR does not require that the person is located near a signal path. Both suggested methods exploit ultra-wideband (UWB) channel impulse response (CIR) measurements. CIR measurements and the modeling of multipath effects either increase the accuracy or reduce the required number of sensors for localization with RTI. We created a test setup and measure UWB CIRs at different positions with a commercially available off-the-shelf UWB radio chip, the Decawave DW1000. We compare the localization results of RTI, multipath-assisted (MA)-RTI, and MSR and investigate a combined approach. We show that RTI is improved by the analysis of multipath propagation; furthermore, MA-RTI results in a better performance compared to MSR: with 50% of all cases, the localization error is better than 0.82 m and in 80% of all cases 1.34 m. The combined approach results in the best localization result with 0.64 m in 50% of all cases.

Theory for the spin caloritronic nano-oscillator

Auto-oscillations of the magnetization in ferromagnetic hybrid nanostructures driven by spin currents produced by a variety of processes have attracted attention for their challenging physics and possible applications, such as microwave assisted magnetic recording, neuromorphic computing, and chip to chip wireless communications. Of particular interest are applications in which the spin current is produced by a thermal gradient in the configuration of the spin Seebeck effect, because it makes it possible to harvest the thermal energy generated in nanodevices. A few years ago, it was demonstrated experimentally that in a simple bilayer made of a thin film of the insulating ferrimagnet yttrium iron garnet in contact with a platinum layer, the application of a temperature difference across the bilayer produced a coherent microwave auto-oscillation. This device was called a spin caloritronic nano-oscillator. Here we show that these experiments are explained quantitatively by a theory based on a mechanism in which one magnon in the spin current splits into two magnons, one of them being the magnon mode resonating at the nanostructure. The theoretical value of the critical temperature gradient necessary to overcome the magnetic damping to produce auto-oscillations is in good agreement with the one employed in the experiments.

Sensor Design Based on Wireless Measurement of Corrosion Monitoring of Reinforced Concrete Structure

Reinforced concrete structures are widely used in modern buildings such as buildings, bridges, and tunnels. However, the structural damage caused by reinforcement corrosion seriously affects the service life of the buildings. Because the corrosion of reinforcement in concrete is a very slow process, the continuous detection of reinforcement corrosion is very important. In view of the slow development of steel corrosion detection equipment in China, which cannot meet the application requirements of concrete structures in China, wireless monitoring technology has more advantages than traditional monitoring technology. In this paper, combined with wireless transmission technology, a concrete reinforcement corrosion detection system based on wireless sensor network is designed. Embedded sensors based on the principle of electromagnetic coupling are used to collect steel corrosion information. It is determined that the 16-bit ultralow power consumption microcontroller MSP430F149 is the main control chip, the AD9850 based on DDS technology is the signal generation chip, and the nRF905 is the detection circuit scheme of the wireless transceiver chip. The star network is determined by polling the entire network topology and MAC protocol. The embedded sensor is designed through simulation. This article discusses the principle of using embedded sensors to detect steel corrosion and determines the feasibility of its low-cost implementation. The embedded sensor and steel corrosion detection system were tested. The simulation method of the embedded sensor is verified through actual measurement. The test results show that the system network is normal and all parts work stably, which can meet the requirements of the project.

Design of leakage prevention and diversion alarm system based on wireless control

Abstract To solve the leakage of contrast agents due to high pressure and fast speed of the high pressure injector, an intelligent anti-leakage system is designed. The pressure sensor MS5837 detects the pressure signal in real time and transmits the pressure signal to MSP430F5529. Once the micro controller detects that the pressure exceeds the threshold value, the leakage of the contrast agent is judged. The controller immediately starts the sound and light alarm and diversion switch function, and informs the medical staff of the clinic to deal with the leakage wound in time through the wireless transmission chip NRF24L01+. This system overcomes the disadvantages of previous mechanical design, such as easy loosening, no diversion. It adds diversion switching function and wireless communication module, which ensures that medical stuff can deal with the wound in the first time without radiation and reduce the leakage damage to the minimum. The results of animal experiments show that the intelligent diversion alarm system is stable, reliable and highly sensitive, which can effectively reduce the leakage of the contrast agents of the high pressure injector and relieve the pain of the patient.

Smart home comfort and energy conservation using internet of things

This new work presents a home automation system which employs internet of things (IoT) technology. This technology streamlines the design with an accurate home automation system which guides against the issues of energy wastage and excessive expenditure on the present systems of the utility company and the consumers. The system deploys a 32-bit ESP8266 system on chip (SoC) wireless fidelity (Wi-Fi) module which is linked to some sensors through a microcontroller for data communication. User friendly remote access, operation and management of the system are achieved through a mobile/web graphic user interface application. Daniel hall of students' residence at Covenant University is the location chosen for the deployment of prototype designed, the overall system achieved approximately 17% savings in energy consumption which in turn reduces the cost of energy usage for the same comform level.

Wireless Rehabilitation Training Sensor Arrays Made with Hot Screen-Imprinted Conductive Hydrogels with a Low Percolation Threshold.

Herein, we propose a highly sensitive wireless rehabilitation training ball with a piezoresistive sensor array for patients with Parkinson's disease (PD). The piezoresistive material is a low percolation threshold conductive hydrogel which is formed with polypyrrole (PPy) nanofibers (NFs) as a conductive filler derived from a polydopamine (PDA) template. The proton acid doping effect and molecular template of PDA are essential for endowing PPy NFs with a high aspect ratio, leading to a low percolation threshold (∼0.78 vol %) and a low Young's 004Dodulus of 37.69 kPa and hence easy deformation. The piezoresistive sensor exhibited a static and dynamic stability of 10,000 s and 15,000 cycle times, respectively. This stability could be attributed to the increased hydrophilicity of conductive fillers, enhancing the interfacial strength between the conductive filler and the matrix. The interaction between the PDA-PPy NFs and the hydrogel matrix endows the hydrogel with toughness and ensures the stability of the device. Additionally, the microdome structure of the conductive hydrogel, produced by hot screen-imprinting, dramatically improves the sensitivity of the piezoresistive sensor (∼856.14 kPa-1). The microdome conductive hydrogel can distinguish a subtle pressure of 15.40 Pa compared to the control hydrogel without a microstructure. The highly sensitive piezoresistive sensor has the potential to monitor the hand-grip force, which is not well controlled by patients with PD. The rehabilitation training ball assembled with a sensor array on the surface and a wireless chip for communication inside is built and used to monitor the pressure in real time through the WeChat applet. Thus, this work has significantly broadened the application of hydrogel-based flexible piezoresistive sensors for human activity monitoring, which provides a promising strategy to realize next-generation electronics.

Software Defined Radio Platforms for Wireless Technologies

Wireless connectivity standards have been developed by standardizing bodies to meet the requirements of various applications. A wireless transceiver should be equipped with a Radio Frequency (RF) transceiver to support a wireless standard. Traditional RF transceivers are designed and implemented on a radio chip or an embedded module in a System-on-a-Chip (SoC), ensuring small size, high performance, low power consumption, and cost. However, this traditional implementation design limits directly or indirectly the programmability and flexibility of the RF transceivers. An alternative solution to implement RF transceivers is using Software Defined Radio (SDR) platforms. In the market, SDR platform hardware exists with different configurations, performance, cost, size, etc., making it hard to select the minimum SDR platform necessary to satisfy the wireless standard requirements. This paper aims to provide a list of well-known General Purpose Processor (GPP) based SDR platforms that meet the minimum specifications of selected wireless standards. To this end, we first review the characteristics of selected wireless technologies. Then, we investigate existing SDR platform architecture and their maximal performance in terms of the frequency range, bandwidth, symbol rate, bitrate, and latency support. Finally, we intersect the wireless standard requirements with the corresponding SDR platform parameters and provide a list of GPP-based SDR platforms for some existing wireless technology implementations. All investigations related to the frequency, bandwidth, symbol rate, and bitrate parameters are supported by theoretical results, whereas latency results are obtained from experiments by benchmarking existing implementations.

An Overview of UWB Standards and Organizations (IEEE 802.15.4, FiRa, Apple): Interoperability Aspects and Future Research Directions

The increasing popularity of ultra-wideband (UWB) technology for location-based services, such as access control and real-time indoor track&tracing, as well as UWB support in new consumer devices such as smartphones, has resulted in the availability of multiple new UWB radio chips. However, due to this increase in UWB device availability, the question of which (industry) standards and configuration factors impact UWB interoperability and compatibility becomes increasingly important. In this paper, the fundamentals of UWB compatibility are investigated by first giving an overview of different UWB radio chips on the market. After that, an overview of UWB standards and organizations is given. Next, this overview is used to discuss the focus of these different standards and to identify the differences between them. We describe compatibility issues and associated interoperability aspects related to physical (PHY), medium-access-control (MAC) and upper layers. For the PHY layer, compatibility is possible for all UWB radio chips if the correct settings are configured. For the MAC layer, the implementation of the multiple access scheme as well as the localization technique is mostly proprietary. For the device discovery, several standards are currently being drafted. Finally, future challenges related to UWB interoperability are discussed.

Intracellular detection and communication of a wireless chip in cell

The rapid growth and development of technology has had significant implications for healthcare, personalized medicine, and our understanding of biology. In this work, we leverage the miniaturization of electronics to realize the first demonstration of wireless detection and communication of an electronic device inside a cell. This is a significant forward step towards a vision of non-invasive, intracellular wireless platforms for single-cell analyses. We demonstrate that a 25 upmu m wireless radio frequency identification (RFID) device can not only be taken up by a mammalian cell but can also be detected and specifically identified externally while located intracellularly. The S-parameters and power delivery efficiency of the electronic communication system is quantified before and after immersion in a biological environment; the results show distinct electrical responses for different RFID tags, allowing for classification of cells by examining the electrical output noninvasively. This versatile platform can be adapted for realization of a broad modality of sensors and actuators. This work precedes and facilitates the development of long-term intracellular real-time measurement systems for personalized medicine and furthering our understanding of intrinsic biological behaviors. It helps provide an advanced technique to better assess the long-term evolution of cellular physiology as a result of drug and disease stimuli in a way that is not feasible using current methods.

6DYN : 6TiSCH with Heterogeneous Slot Durations.

New radio chips implement different physical layers, allowing firmware to change modulation, datarate and frequency dynamically. This technological development is an opportunity for industrial low-power wireless networks to offer even higher determinism, including latency predictability. This article introduces 6DYN, an extension to the IETF 6TiSCH standards-based protocol stack. In a 6DYN network, nodes switch physical layer dynamically on a link-by-link basis, in order to exploit the diversity offered by this new technology agility. To offer low latency and high network capacity, 6DYN uses heterogeneous slot durations: the length of a slot in the 6TiSCH schedule depends on the physical layer used. This article shows how reserved bits in 6TiSCH headers can be used to standardize 6DYN and details its implementation in OpenWSN, a reference implementation of 6TiSCH.

(Plenary) The Revival of Compound Semiconductors and How They Will Change the World in a 5G/6G Era

Compound semiconductor devices have always intrigued the semiconductor industry due to their high intrinsic mobilities and the heterostructure engineering enabled by those materials. While CMOS has been the vehicle pushing the industry to ever smaller devices, better performance and of course reduced cost, the unique properties of compound semiconductor devices are finding renewed interest in an era where an increasing amount of data is being sent around, stored and analyzed. While several applications like photonics, high-power electronics and image sensors also benefit from enabling a variety of III-V materials and devices, specifically, in the RF Front-End Modules of 5G radio chips [1], these materials allow to address the challenges related to speed, efficiency and output power needed for this next generation wireless communication standard. And while 5G is in full deployment, with first addressing the sub-6GHz frequency bands and in a later phase the mm-wave frequency bands, first publications are already appearing on 6G, where even higher frequencies (beyond > 100GHz) will be targeted [2].GaN [3] and InP-based devices [4] have a clear performance advantage over Si CMOS and SiGe HBT/BICMOS, but their lower integration potential, still restricted to smaller size substrates and lab-like processing today, is one of the key limitations for adopting those technologies for high-volume 5G and 6G applications. Upscaling those devices to a 200mm/300mm Si platform will be a first step to improve yield and maturity and increase complexity. In a second phase, upscaling and maturing these technologies will allow to co-integrate these devices, usually quite dissimilar to CMOS, with advanced Si technology nodes and provide a fully integrated heterogeneous system.In this talk, we will review the status and progress toward integrating these devices on a CMOS-compatible platform.

No Free Lunch-Characterizing the Performance of 6TiSCH When Using Different Physical Layers.

Low-power wireless applications require different trade-off points between latency, reliability, data rate and power consumption. Given such a set of constraints, which physical layer should I be using? We study this question in the context of 6TiSCH, a state-of-the-art recently standardized protocol stack developed for harsh industrial applications. Specifically, we augment OpenWSN, the reference 6TiSCH open-source implementation, to support one of three physical layers from the IEEE802.15.4g standard: FSK 868 MHz which offers long range, OFDM 868 MHz which offers high data rate, and O-QPSK 2.4 GHz which offers more balanced performance. We run the resulting firmware on the 42-mote OpenTestbed deployed in an office environment, once for each physical layer. Performance results show that, indeed, no physical layer outperforms the other for all metrics. This article argues for combining the physical layers, rather than choosing one, in a generalized 6TiSCH architecture in which technology-agile radio chips (of which there are now many) are driven by a protocol stack which chooses the most appropriate physical layer on a frame-by-frame basis.

Timestamp-Free Clock Syntonization for IoT Using Carrier Frequency Offset

System-level timing fluctuations caused by unstable low-cost clocks and end-to-end communication delays are the main sources of uncertainties in existing synchronization mechanisms that rely on timestamp exchanges. This paper introduces a timestamp-free clock syntonization approach, carrier frequency offset (CFO)-assisted syntonization (CFOSynt), to estimate the clock skew between a pair of nodes by utilizing carrier frequency offset. To enable CFOSynt, we leverage the fact that RF oscillators in the radio can be used as the reference to calibrate the system clock oscillators, and the pairwise RF clock information is carried in the transmission carrier frequency. By incorporating CFO and capturing the clock frequency relationship in system clock skew estimation, CFOSynt can eliminate the need for timestamping and the impact of delay uncertainties. To validate the design, CFOSynt is implemented on two common off-the-shelf (COTS) IoT platforms with access to the CFO estimation from the radio chip. Extensive experiments are conducted to evaluate CFOSynt, and CFOSynt can estimate the clock skew of 32 kHz low-cost electronic oscillators with a mean error of -2.46 Hz. In comparison with timestamp-based approaches, CFOSynt achieves up to 70-90% improvement in skew estimation error and shows significant reliability when low-cost oscillators are used.

Validation of an ear tag–based accelerometer system for detecting grazing behavior of dairy cows

The objective of the study was to develop a grazing algorithm for an ear tag-based accelerometer system (Smartbow GmbH, Weibern, Austria) and to validate the grazing algorithm with data from a noseband sensor. The ear tag has an acceleration sensor, a radio chip, and temperature sensor for calibration and it can monitor rumination and detect estrus and localization. To validate the ear tag, a noseband sensor (RumiWatch, Itin and Hoch GmbH, Liestal, Switzerland) was used. The noseband sensor detects pressure and acceleration patterns, and, with a software program specific to the noseband, pressure and acceleration patterns are used to classify data into eating, ruminating, drinking, and other activities. The study was conducted at the University of Minnesota West Central Research and Outreach Center (Morris, MN) and at Teagasc Animal and Grassland Research and Innovation Centre (Moorepark, Fermoy, Co. Cork, Ireland). During May and June 2017, observational data from Minnesota and Ireland were used to develop the grazing algorithm. During September 2018, data were collected by the ear tag and noseband sensor from 12 crossbred cows in Minnesota for a total of 248 h and from 9 Holstein-Friesian cows in Ireland for a total of 248 h. A 2-sided t-test was used to compare the percentage of grazing and nongrazing time recorded by the ear tag and the noseband sensor. Pearson correlations and concordance correlation coefficients (CCC) were used to evaluate associations between the ear tag and noseband sensor. The percentage of total grazing time recorded by the ear tag and by the noseband sensor was 37.0% [95% confidence interval (CI): 32.1 to 42.0] and 40.5% (95% CI: 35.5 to 45.6), respectively, in Minnesota, and 35.4% (95% CI: 30.6 to 40.2) and 36.9% (95% CI: 32.1 to 41.8), respectively, in Ireland. The ear tag and noseband sensor agreed strongly for monitoring grazing in Minnesota (r = 0.96; 95% CI: 0.94 to 0.97, CCC = 0.95) and in Ireland (r = 0.92; 95% CI: 0.90 to 0.94, CCC = 0.92). The results suggest that there is potential for the ear tag to be used on pasture-based dairy farms to support management decision-making.

A Batteryless Padless Crystalless 116 $\mu$ m$\,\times$ 116 $\mu$ m “Dielet” Near-Field Radio With On-Chip Coil Antenna

Batteryless compact radios are highly needed to realize many Internet-of-Things (IoT) applications, such as miniaturized radio-frequency identification (RFID), wearable/implantable devices, and counter-counterfeit electronics. To miniaturize the radios, it is necessary to integrate an antenna on chip to transfer both power and data, eliminating the I/O pads and crystal. In addition, the ultra-small die area precludes the use of any on-chip energy storage (such as large capacitors or inductors); therefore, sufficient power must be supplied wirelessly. As a result, two challenges must be overcome for uplink communication. First, the wireless power tone acts as a large blocker for the uplink communication signal, resulting in a poor uplink signal-to-noise ratio (SNR). Second, without a crystal, the on-chip oscillator will be noisy and subject to further degrading the uplink SNR. In this article, we have demonstrated an RFID system used to detect counterfeit electronics that addresses the design challenges by the proposed two-tone technique. With an overall dimension of 116 $\mu \text{m}\,\,\times $ 116 $\mu \text{m}$ , the “dielet” radio chip is fabricated by a 65-nm CMOS technology, which is batteryless, padless, and crystalless. This is the smallest functional radio chip to date, and the measurement results show that both the uplink signal-to-blocker ratio (SBR) and SNR can be improved by the new two-tone technique.