Wireless Transmission Research Articles

Advanced flame-retardant melamine foam with ultra-sensitivity and prolonged fire warning, featuring smart device-integrated graphene oxide/attapulgite nano-coating

Enhancing flame retardancy and fire-warning capabilities of thermal insulation materials used in building external walls is crucial for ensuring fire safety as well as guarding people's lives and assets. Herein, we have developed an environmentally friendly nano-coating that possesses flame-retardant and early-warning properties by integrating graphene oxide (GO) and attapulgite (ATP) onto melamine foam (MF) through a layer-by-layer self-assembly method (LBL). The GO-ATP-MF composite demonstrates a rapid response to flame (<1 s) due to GO's thermally induced reduction. Additionally, ATP's synergistic flame-retardant effects on both gas and condensed phases contribute to outstanding flame retardancy, enabling an enduring fire alarm duration (>1330 s). The warning duration time of this composite surpasses the majority of GO-based fire-warning nano-coatings reported to date. Moreover, incorporating a Bluetooth wireless transmission system facilitates real-time fire information sharing among smart devices, thereby optimizing fire signal transmission efficiency. Thus, this study advances GO-based flame-retardant nano-coatings and devices with high sensitivity and prolonged fire-warning capabilities, providing an innovative idea to enhance the fire safety of MF as a thermal insulation material.

Real-Time and Wireless Transmission of a Nitrogen-Doped Ti3C2Tx Wearable Gas Sensor for Efficient Detection of Food Spoilage and Ammonia Leakage.

With the rising popularity of smart homes, there is an urgent need for devices that can perform real-time online detection of ammonia (NH3) concentrations for food quality measurement. In addition, timely warning is crucial to preventing individual deaths from NH3. However, few studies can realize continuous monitoring of NH3 with high stability and subsequent application validation. Herein, we report on an integrated device equipped with a nitrogen-doped Ti3C2Tx gas sensor that shows great potential in detecting food spoilage and NH3 leakage. The nitrogen doping results in the lattice misalignment of Ti3C2Tx, subsequently realizing effective barrier height modulation and enhanced charge transfer efficiency of nitrogen-doped Ti3C2Tx. Density functional theory calculations confirm the greatly enhanced adsorption of NH3 on nitrogen-doped Ti3C2Tx. Our work can inspire the design of efficient gas sensors for real-time and wireless detection of food spoilage and NH3 leakage.

Accurate Low Complexity Quadrature Angular Diversity Aperture Receiver for Visible Light Positioning.

Despite the many potential applications of an accurate indoor positioning system (IPS), no universal, readily available system exists. Much of the IPS research to date has been based on the use of radio transmitters as positioning beacons. Visible light positioning (VLP) instead uses LED lights as beacons. Either cameras or photodiodes (PDs) can be used as VLP receivers, and position estimates are usually based on either the angle of arrival (AOA) or the strength of the received signal. Research on the use of AOA with photodiode receivers has so far been limited by the lack of a suitable compact receiver. The quadrature angular diversity aperture receiver (QADA) can fill this gap. In this paper, we describe a new QADA design that uses only three readily available parts: a quadrant photodiode, a 3D-printed aperture, and a programmable system on a chip (PSoC). Extensive experimental results demonstrate that this design provides accurate AOA estimates within a room-sized test chamber. The flexibility and programmability of the PSoC mean that other sensors can be supported by the same PSoC. This has the potential to allow the AOA estimates from the QADA to be combined with information from other sensors to form future powerful sensor-fusion systems requiring only one beacon.

Advances in EV wireless charging technology – A systematic review and future trends

Current advancements in wireless power transfer systems have improved the viability of enhancing the scope of the driving journey of an Electric Vehicle. This paper addresses the prime aspects of wireless charging infrastructure using a systematic approach, such as compensation topologies, power converter circuit design, and power transfer methods. The exclusive wireless charging track on the road minimizes the size of the battery device and the charging duration of energy storage during driving. The ability to transmit high power through a coil placed on the road to the Electric Vehicle requires an appropriate design for the complete wireless power transmission module. This paper also presents advancements in the domain of wireless technologies and recommends upcoming opportunities and future research trends.

Enhancing Security of Telemedicine Data: A Multi-Scroll Chaotic System for ECG Signal Encryption and RF Transmission.

Protecting sensitive patient data, such as electrocardiogram (ECG) signals, during RF wireless transmission is essential due to the increasing demand for secure telemedicine communications. This paper presents an innovative chaotic-based encryption system designed to enhance the security and integrity of telemedicine data transmission. The proposed system utilizes a multi-scroll chaotic system for ECG signal encryption based on master-slave synchronization. The ECG signal is encrypted by a master system and securely transmitted to a remote location, where it is decrypted by a slave system using an extended state observer. Synchronization between the master and slave is achieved through the Lyapunov criteria, which ensures system stability. The system also supports Orthogonal Frequency Division Multiplexing (OFDM) and adaptive n-quadrature amplitude modulation (n-QAM) schemes to optimize signal discretization. Experimental validations with a custom transceiver scheme confirmed the system's effectiveness in preventing channel overlap during 2.5 GHz transmissions. Additionally, a commercial RF Power Amplifier (RF-PA) for LTE applications and a development board were integrated to monitor transmission quality. The proposed encryption system ensures robust and efficient RF transmission of ECG data, addressing critical challenges in the wireless communication of sensitive medical information. This approach demonstrates the potential for broader applications in modern telemedicine environments, providing a reliable and efficient solution for the secure transmission of healthcare data.

A wireless, battery-free device for electrical neuromodulation of bladder contractions

Lower urinary tract dysfunction (LUTD) is a prevalent condition characterized by symptoms such as urinary frequency, urgency, incontinence, and difficulty in urination, which can significantly impair patient's quality of life and lead to severe physiological complications. Despite the availability of diverse treatment options, including pharmaceutical and behavioral therapies, these approaches are not without challenges. The objective of this study was to enhance treatment options for LUTD by developing a wireless, battery-free device for managing bladder contractions. We designed and validated a compact, fully implantable, battery-free pulse generator using the magnetic induction coupling mechanism of wireless power transmission. Weighing less than 0.2 g and with a volume of less than 0.1 cubic centimeters, this device enables precise stimulation of muscles or neurons at voltages ranging from 0 to 10 V. Wireless technology allows real-time adjustment of key stimulation parameters such as voltage, duration, frequency, pulse width, and pulse interval. Our findings demonstrate that the device effectively controlled bladder contractions in mice when used to stimulate the Major Pelvic Ganglion (MPG). Additionally, the device successfully managed micturition in mice with bilateral transection of the pudendal nerve. In conclusion, the development of this innovative wireless pulse generator provides a safer and more cost-effective alternative to conventional battery-powered neurostimulators for bladder control, addressing the limitations of such devices. We anticipate that this novel technology will play a pivotal role in the future of electrical stimulation therapies for voiding dysfunctions.

Wearable Fall Detectors Based on Low Power Transmission Systems: A Systematic Review

Early attention to individuals who suffer falls is a critical aspect when determining the consequences of such accidents, which are among the leading causes of mortality and disability in older adults. For this reason and considering the high number of older adults living alone, the development of automatic fall alerting systems has garnered significant research attention over the past decade. A key element for deploying a fall detection system (FDS) based on wearables is the wireless transmission method employed to transmit the medical alarms. In this regard, the vast majority of prototypes in the related literature utilize short-range technologies, such as Bluetooth, which must be complemented by the existence of a gateway device (e.g., a smartphone). In other studies, standards like Wi-Fi or 3G communications are proposed, which offer greater range but come with high power consumption, which can be unsuitable for most wearables, and higher service fees. In addition, they require reliable radio coverage, which is not always guaranteed in all application scenarios. An interesting alternative to these standards is Low Power Wide Area Network (LPWAN) technologies, which minimize both energy consumption and hardware costs while maximizing transmission range. This article provides a comprehensive search and review of that works in the literature that have implemented and evaluated wearable FDSs utilizing LPWAN interfaces to transmit alarms. The review systematically examines these proposals, considering various operational aspects and identifying key areas that have not yet been adequately addressed for the viable implementation of such detectors.

Security in the era of wireless innovations: analysis of potential threats and protective measures

In today's interconnected world, wireless data transmission technologies have seamlessly integrated into the fabric of modern business operations. As reliance on these technologies grows, so does the imperative to ensure robust cyber security measures. Particularly in the age of wireless innovations, exemplified by the proliferation of the Internet of Things (IoT), the discourse surrounding the security of wireless technologies underscores the necessity of comprehending both established threats and the continuous emergence of new vulnerabilities. This underscores the urgent need for timely detection and mitigation strategies. While the convenience afforded by wireless data transmission technologies grants society unprecedented access to information and facilitates the management of diverse devices, processes, and systems, it also exposes users and modern information and communication systems (ICS) to significant cyber threats and vulnerabilities. Consequently, there arises a pressing need to address these challenges comprehensively. This research dissects contemporary methodologies aimed at restricting access to wireless networks, identifying potential vulnerabilities, and crafting effective responses to cyberattacks. It delves into various facets of cyber security, including data encryption, user authentication mechanisms, traffic monitoring protocols, and anomaly detection algorithms. Furthermore, it delves into the crucial aspect of educating personnel on wireless security practices, equipping them with threat awareness and incident response capabilities. Given the dynamic landscape of cybersecurity technologies and threats, this work seeks to establish a foundational understanding of the security landscape within wireless networks. By doing so, it aims to outline pragmatic strategies for effectively managing security risks, thereby fortifying the resilience of modern organizations and safeguarding critical information assets.

Postbreeding ecology of wood ducks in the Illinois River Valley

AbstractThe wood duck (Aix sponsa) consistently ranks within the top 5 harvested duck species for both Illinois and the Mississippi Flyway. While substantial research has been done on wood ducks, especially their breeding ecology, few studies have investigated the postbreeding ecology of the species. We captured and marked wood ducks with either a very high frequency (VHF) radio transmitter or a solar‐charged global system of mobile communication (GSM) transmitter during the postbreeding period from August through September 2018–2020. Capture locations were within the La Grange Pool of the Illinois River extending from near Pekin, Illinois to the La Grange Lock and Dam near Meredosia, Illinois, USA. We used conventional radio‐telemetry techniques to track wood ducks to determine cover type use, home range size, daily movement patterns, survival, and migration chronology. Home range size (95% minimum convex polygon) for wood ducks averaged 6,820 ± 572 ha (SE) and we did not find evidence for a difference by age, sex, or transmitter type. Daily movement distance in August (2,031 ± 51 m) was similar to daily movement distance in September (1,922 ± 44 m), but daily movement distances for August and September were less than daily movement distance for October (3,509 ± 53 m) and November (3,347 ± 106 m). Wood ducks primarily used wetlands with woody (45.0%) and emergent vegetation (40.4%), and the most commonly used wetland types by wood ducks were impounded wetlands (53.8%), lakes (17.6%), and ponds (10.7%). Model‐derived survival during the postbreeding period was 0.79 (95% CI = 0.74–0.84). Daily survival was positively related to increased river level and had a mean increase of 4.06 ± 0.67% for every 0.3‐m increase in the Illinois River level at low river levels (1.5–3.0 m) and a mean increase of 1.38 ± 0.32% for every 0.3‐m increase in the Illinois River level at high river levels (4.0–5.5 m). Average departure date of wood ducks leaving the Illinois River Valley was 27 October (range =13 August–15 December), and adult male wood ducks left the study area 11–16 days earlier than the other age and sex cohorts (H2 = 11.6, P = 0.01). Providing additional waterfowl sanctuaries that contain wooded wetlands, especially in years of low river levels, may increase survival for wood ducks during the postbreeding period.

Self-powered strain sensing devices with wireless transmission: DIW-printed conductive hydrogel electrodes featuring stretchable and self-healing properties

With rapid advancements in health and human–computer interaction, wearable electronic skins (e-skins) designed for application on the human body provide a platform for real-time detection of physiological signals. Wearable strain sensors, integral functional units within e-skins, can be integrated with Internet of Things (IoT) technology to broaden the applications for human body monitoring. A significant challenge lies in the reliance of most existing wearable strain sensors on rigid external power supplies, limiting their practical flexibility. In this study, we present an innovative strategy to fabricate glutaraldehyde (GA)-poly(vinyl alcohol) (PVA)/cellulose nanocrystals (CNC)/Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) conductive hydrogels through multiple hydrogen bonding systems. Combining the advantageous rheological properties of the precursor solution and the high specific surface area after freeze–thaw cycling, we have created a self-powered sensing system prepared by large-area printing using direct ink writing (DIW) printing. The resulting conductive hydrogel exhibits commendable mechanical properties (411 KPa), impressive stretchability (580 %), and robust self-healing capabilities (>98.3 %). The strain sensor, derived from the conductive hydrogel, demonstrates a gauge factor (GF) of 2.5 within a stretching range of 0–580 %. Additionally, the resultant supercapacitor displays a peak energy density of 0.131 mWh/cm3 at a power density of 3.6 mW/cm3. Benefiting from its elevated strain response and remarkable power density features, this self-powered strain sensing system enables the real-time monitoring of human joint motion. The incorporation of a 5G transmission module enhances its capabilities for remote data monitoring, thereby contributing to the progress of wireless tracking technologies for self-powered electronic skin.

A Wireless Ad Hoc Network Communication Platform and Data Transmission Strategies for Multi-Bus Instruments

As automatic test technology advances, the number of programmable instruments in a single test system increases. Traditional wired communication methods have a limited range and involve complex cable layouts. Single-function wireless converters provide a viable alternative, but they have limitations. These include complicated configuration, issues with multi-system collaboration, and data blocking. This paper proposes a wireless ad hoc network platform for multi-bus instruments based on a low-cost ESP-12H WiFi module. The platform supports GPIB, RS232, RS485, and CAN bus interface instrument access. It features easy configuration, ad hoc networking, and self-repairing capabilities. A relay multi-hop network with a tree topology expands capacity and coverage. Additionally, a dynamic window-receiving mode and an improved multi-priority queue ensure data transmission integrity. The experimental results show that the platform’s networking time is less than 10 s, and the coverage range reaches 50 m in complex indoor environments. It also shows good stability when running for a long time. However, due to hardware and software design limitations, the actual upload speeds fall short of the theoretical values. For example, RS232 and RS485 are about 10% slower than the theoretical values, and GPIB is about 80% slower. Further optimization is required in the future.

Circadian clock period length is not consistently linked to chronotype in a wild songbird.

Circadian clock properties vary between individuals and relate to variation in entrained timing in captivity. How this variation translates into behavioural differences in natural settings, however, is poorly understood. Here, we tested in great tits whether variation in the free-running period length (tau) under constant dim light (LL) was linked to the phase angle of the entrained rhythm ("chronotype") in captivity and in the wild, as recently indicated in our study species. We also assessed links between tau and the timing of first activity onset and offset under LL relative to the last experienced light-dark (LD) cycle. We kept 66 great tits, caught in two winters, in LL for 14 days and subsequently released them with a radio transmitter back to the wild, where their activity and body temperature rhythms were tracked for 1 to 22 days. For a subset of birds, chronotype was also recorded in the lab before release. Neither wild nor lab chronotypes were related to tau. We also found no correlation between lab and wild chronotypes. However, the first onset in LL had a positive relationship with tau, but only in males. Our results demonstrate that links between tau and phase of entrainment, postulated on theoretical grounds, may not consistently hold under natural conditions, possibly due to strong masking. This calls for more holistic research on how the many components of the circadian system interact with the environment to shape timing in the wild. Wild birds showed chronotypes in the field that were unlinked to their circadian period length tau measured in captivity. In males only, the first onset of activity after exposure to constant dim light did correlate with tau. Our study emphasises the need to investigate clocks in the real world, including a need to better understand masking.

Intelligent fibers and textiles for wearable biosensors

AbstractIn conjunction with the advancement of digital healthcare, the field of wearable biosensors has experienced rapid growth in recent years and is projected to expand further in the coming years. As wearable biosensors enter their next phase, emphasis is increasingly placed on developing comfortable, breathable, washable, and lightweight intelligent fibers and textiles as key components. This review examines the contributions of both natural and synthetic fibers and textiles to wearable biosensors. The structure and preparation process of intelligent fibers and textiles are systematically elucidated, including the development of the conductive layer. Additionally, key micro–nano technologies that have emerged in this domain are highlighted such as built‐in power supplies, wireless data transmission, precise data analysis driven by artificial intelligence, and machine learning. Furthermore, advanced functionalities integrated into recent biosensing systems, such as heat management, real‐time displays, and human–machine interaction are summarized. Moreover, the applications of fiber‐based wearable biosensors for monitoring biophysical and biochemical signals are presented. Finally, the challenges faced by the community working on wearable sensors based on intelligent fibers and textiles are discussed alongside promising future directions.

A microfluidic patch for wireless wearable electrochemical detection of sweat metabolites

Wearable sweat sensors provide an innovative detection method for analyzing human physiological and biochemical parameters and play an important role in detecting the potential risks of chronic diseases. Existing commercial wearable sensors (Apple iWatch, HUAWEI smart band) have problems such as single detection index (heart rate or blood pressure), and mainly focus on the physical information. This work studied an integrated microfluidic patch to simultaneously detect several biomarkers (pH, sodium ions, and uric acid) in sweat. We achieved the detection of pH level, sodium, and uric acid in linear ranges of 4–8, 0–160 mM, and 5–160 μM, respectively, covering well the clinically relevant ranges in the healthy human sweat. Laser engraving was chosen to prepare a microfluidic layer, and the sweat collection function was realized by combining hydrophilic and hydrophobic microfluidic synergy. It could efficiently collect the required sweat sample volume (80 μL) within 30 s while avoiding the contamination caused by directly contact with the skin. In addition, a wireless signal acquisition and transmission system was designed with the signal reading, processing, and wireless transmission functions, which can display the testing results in real time on Android phone-specific application software. We combined the wireless system with a microfluidic patch for on-body testing to verify the good wearability of the sweat sensor. This research realized the wireless data processing and transmission while improving sweat collection efficiency. In addition, it could detect various sweat physiological components in real-time, and provides a multiparameter, real-time, and portable sensing platform.

Development of a Frugal Onboard Tire Pressure Monitoring Control System

Tires, the bridge between vehicles and roads, play an unparalleled role in both performance and safety. In everyday use, the tire health is often neglected, with factors such as tread depth, inflation pressure, and tire damage overlooked by most users, leading to ∼\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim$$\\end{document}30% of cars in developed nations, operating with underinflated tires, a situation exacerbated in developing nations. Hence, innovations such as tire Pressure Monitoring Systems have become imperative. The objective of the current work is to develop an economical, direct, on-board tire pressure monitor for automotive tire health upkeep. This is achieved through the integration of a pressure sensor and transmitter with an Arduino, and wireless transmission of the data to the dashboard display. While the initial model, tested on a bicycle, effectively displayed tire pressure on the handlebar-mounted LCD screen with an accompanying LED indicating deviations from the standard pressure, the current design has lot of scope for improvement by the utilization of a wireless technologies for the pressure sensors for continuous monitoring of tire pressures in a range of vehicles from two-wheelers to heavy vehicles.

Flexible Wearable Chemoresistive Ethylene Gas-Monitoring Device Utilizing Pd/Ti3C2Tx Nanocomposites for In Situ Nondestructive Monitoring of Kiwifruit Ripeness.

Kiwifruit, renowned for its antioxidant properties and nutritional richness, faces challenges in maintaining quality during transportation, often leading to suboptimal products reaching the market. To address this issue, a wireless transmission flexible ethylene monitoring device (WFEMD) was developed. This device comprises a flexible ethylene gas sensor and a signal transmission processing unit integrated with electronic components, enabling real-time monitoring capabilities. In this study, the catalytic activity of Pd and Pd/Ti heterojunctions was leveraged to enhance the ethylene gas sensing. The impact of Ti3C2Tx modified with varying masses of Pd nanoparticles on ethylene gas response levels was investigated. The signal transmission processing unit, fabricated by using the laser direct-writing method, was optimized to collect signals from the flexible ethylene gas sensor, convert them into corresponding ethylene concentrations, and transmit data via an antenna. By introducing a random forest (RF) classification algorithm, a remarkable 97.5% accuracy in predicting kiwifruit ripeness grades was achieved. The algorithm facilitated precise classification by collecting key parameters such as ethylene and CO2 during transportation. The WFEMD enables real-time acquisition of kiwifruit ethylene gas information, which is transmitted wirelessly for data visualization and traceability via mobile terminals. This empowers managers with timely insights into ethylene emissions and ripeness predictions, facilitating informed decision-making processes.

An Analysis of Routing Protocol in Mobile Adhoc Networks and its Applications

Each hub in a mobile ad-hoc network (MANET) sends parcels bound for different hubs in the network by means of remote (radio transmission) transmission on a wilful premise, making it a self-beginning, powerful network made up of mobile hubs. Multi-bounce transferring is the essential inspiration for the advancement of ad hoc networking. Remote Ad hoc networks, otherwise called foundation less networks, can be set up rapidly and effectively using radio waves as the network's transmission channel. There is no principal server or referee in an ad hoc network. Every hub in a MANET is fit for playing out its own networking errands, for example, routing and bundle sending, in a decentralized and independent style. Uses of routing protocols like Ad hoc On-request Distance Routing Protocol (AODV), Dynamic Source Routing (DSR), Transiently Requested Routing Calculation (TORA), and Enhanced Connection State Routing (OLSR) are fascinating in light of the fact that routing is the focal issue in MANETs. These routing protocols are simulated using OPNET, and their effectiveness is investigated using various metrics. With the use of metrics, the most efficient channel for data transfer can be determined. The results demonstrate the viability of AODV and TORA for topology-changing in large-scale networks using a variety of criteria.

Photonics-aided exceeding 200-Gb/s wireless data transmission over outdoor long-range 2 × 2 MIMO THz links at 300 GHz

Outdoor long-range terahertz (THz) communications often come at the expense of transmission rate. Moreover, the practicability of the single polarization optical/THz link, which is commonly used in the previous long-range THz demonstrations based on photonics, is extremely limited by the following two fatal defects. One is relying on active polarization control, and the other is not supporting the transparent bridging of optical polarization division multiplexed (PDM) signals for mature coherent optical communication networks. In this work, a large-capacity photonics-aided THz wireless communication system based on the outdoor long-range 2 × 2 multiple-input multiple-output (MIMO) links has been successfully demonstrated. We first build the 200-m 2 × 2 MIMO THz wireless links at the 300 GHz band. The cascaded linear and nonlinear equalizers are proposed which can significantly improve the transmission performance of 100- and 200-Gb/s PDM quadrature phase shift keying (QPSK) signals. Then an interesting 2 × 2 MIMO structure which can provide certain diversity reception gain under 200-m long-range wireless delivery using the same polarization scheme is also presented and further compared with the orthogonal polarization scheme. Since each THz receiver simultaneously receives data from both the two THz transmitters for this MIMO links, an improvement over 6 dB in receiving sensitivity and one order of magnitude in bit error ratio performance under low signal-to-noise ratio conditions can be achieved. Finally, based on the proposed cascaded equalizers and novel 2 × 2 MIMO structure, we successfully demonstrate a record-breaking 58-Gbaud (232-Gb/s) PDM-QPSK signal transmission over 200-m 2 × 2 MIMO THz wireless links. This is an important attempt for the photonics-aided THz wireless communication systems to achieve 2 × 2 MIMO transmission over a long wireless distance in the outdoors. Furthermore, attaining over 200 Gb/s at a wireless distance of 200 m also represents a key milestone for the long-range and large-capacity THz wireless communication systems.

BROADBAND SEISMIC NODE BASED ON LOW-NOISE HIGH-SENSITIVITY MOLECULAR-ELECTRONIC SENSORS

The developed wideband compact digital seismic module designed for use in ground nodal seismic systems with deployment assistance from unmanned aerial vehicle (UAV) is discussed. The operation frequency band is 1–300 Hz, which is by far wider than that of the seismic nodes based on using standard (10Hz) electrodynamic geophones. Such improvement was achieved through the use of highly sensitive seismic sensors with molecular electronic transfer (MET) that allow for covering a low-frequency part of the spectrum that is needed for broadband processing and receiving information on deep subsurface formation. Low self-noise of the MET seismic sensors used for this seismic station has been proven in special tests. According to the test results, measurements of the self-noise of the developed sensor turned out to be 27-30 dB lower than the self-noise of similar sensors with additional mass. Besides of the 3 mutually orthogonal wideband MET sensors the developed module consists of a digital electronics block enabling autonomous registration and featuring wireless data transmission capability; a battery compartment providing autonomous operation of the seismic module; a device for attaching the seismic module to UAVs and lowering it to the ground. The developed device ensures data time synchronization with satellites, records data at frequencies up to 1000 samples per second with 24 bits resolution and stores the recorded information on the internal 32 Gb storage. A distinctive feature of the presented seismic node is the implementation of quality control of seismic data using a drone. This function is implemented on a Raspberry Pi single-board computer installed on board of the UAV, which has the ability to retrieve portion of information from the node for data quality control and initiate calibration procedure.

Sum-Rate Maximization for a Hybrid Precoding-Based Massive MIMO NOMA System with Simultaneous Wireless Information and Power Transmission

Non-orthogonal multiple access (NOMA) has emerged as a key enabling technology in the realm of millimeter-wave (mmWave) massive MIMO (mMIMO) systems for enhancing spectral efficiency (SE). Furthermore, it is believed that simultaneous wireless information and power transmission (SWIPT) will allow for the system’s energy efficiency (EE) to be maximised. The effectiveness of the mmWave mMIMO-NOMA system along with SWIPT has been examined in this article under multi-user (MU) scenarios. This paper’s major goal is to construct a low-complexity hybrid-precoder (HP) while taking into account the sub-connected (SC) architecture. The linear precoder is a computationally demanding technique as a result of the matrix inversion. The authors of this paper have suggested a symmetric sequential over-relaxation (SSOR) complex regularised zero-forcing (CRZF) linear precoder. The power distribution for the mmWave mMIMO-NOMA system and power splitting factors for SWIPT are jointly tuned to maximize the sum rate along with the suggested SSOR-CRZF precoder. In regards to complexity, SE, and EE, the SSOR-CRZF-HP surpasses conventional linear precoders.