Low Transmission Power Research Articles

Semantic-Driven Efficient Service Network Towards Smart Healthcare System in Intelligent Fabric

The advantages of intelligent fabrics enable health service systems more efficient and safe to perceive and transmit, where massive sensitive data related to health and behavior are collected through the multi-source flexible sensor network. However, due to its complex network structure, health service systems face the challenge of low-power data transmission and processing in intelligent fabric space. Recently, Deep learning-powered semantic communication (Deep-SC) has emerged as a promising communication paradigm. To tackle the above problem, we introduce the concept of semantic cognition into the cyber-physical system of health service and present the Deep-SC based network service framework for the healthcare system, where physical layer blocks are merged into the traditional communication system to jointly optimize the transceiver in communication. Since semantic encoding and decoding require additional knowledge, consider the introduction of the semantic knowledge base in the system to formulate the joint optimization problem of service offloading and bandwidth allocation in the proposed network service framework, with the goals of reliable semantic communication and efficient network transmission. Furthermore, an online algorithm that optimally adapts service offloading and subcarrier allocation decisions to the time-varying channel conditions is required. Finally, we use a reinforcement learning-based decision algorithm to solve combinatorial optimization problems, which further reduces the computing complexity. Experimental results show that the proposed framework achieves significant performance improvements in system energy consumption and reliable transmission, compared with traditional communication strategies.

An energy‐efficient power allocation algorithm under reliability constraint for industrial Internet of Thing systems

SummaryWith the development of 5G technology, the Internet of Things (IoT) system is becoming more and more widely used in various fields. However, the reliability issue still hinders the wide applications. For instance, the transmission reliability of the IoT system will be significantly affected by the status of end devices, wireless channel quality, and the environment. Moreover, according to the Automatic Repeat‐reQuest (ARQ) retransmission mechanism in the 802.15.4 protocol, if the IoT end devices pursue a conservative power model causing low signal transmission power, it is likely that the signal power will lose too much during the transmission process. This will result in the increase of the network packet loss rate and the power consumption during the data retransmission. To solve this problem, this paper proposes a reasonable transmission power allocation algorithm to ensure the transmission reliability, considering the ARQ retransmission mechanism. The algorithm intends to find the optimal transmission power of each IoT end device, so as to minimize the total energy consumption. The simulation results demonstrate that the power allocation algorithm improves the reliability of the IoT system, compared with other algorithms.

Periodic-Filtering Method for Low-SNR Vibration Radar Signal

Radar is a non-contact, high-precision vibration measurement device and an important tool for bridge vibration monitoring. Vibration information needs to be extracted from the radar phase, but the radar phase information is sensitive to noise. Under low signal-to-noise ratio (SNR) data acquisition conditions, such as low radar transmission power or a long observation distance, differential phase jump errors occur and clutter estimation becomes difficult, which leads to inaccurate inversion of vibration deformation. Traditional low-pass filtering methods can filter out noise to improve SNR, but they require oversampling. The sampling rate needs to be several times higher than the Doppler bandwidth, which is several times higher than the vibration frequency. This puts high data acquisition requirements on radar systems and causes large data volumes. Therefore, this paper proposes a novel vibration signal filtering method called the periodic filtering method. The method uses the periodicity feature of vibration signals for filtering without oversampling. This paper derives the time-domain and frequency-domain expressions for the periodic filter and presents a deformation inversion process based on them. The process involves extracting the vibration frequency in the Doppler domain, suppressing noise through periodic filtering, estimating clutter using circle fitting on the data complex plane, and inverting final deformation with differential phase. The method is verified through simulation experiments, calibration experiments, and bridge vibration experiments. The results show that the new periodic filtering method can improve the SNR by five times, resolve differential phase jumps, and accurately estimate clutter, thus getting submillimeter-level vibration deformation at low SNR.

Optically Transparent MIMO Antenna with Polarisation Diversity for Vehicular Communications

ABSTRACT A unique multiple-input-multiple-output (MIMO) adaptive intelligent antenna for vehicular communications is addressed in this article. It has a high degree of transparency that can be integrated with the windscreen for intelligent vehicular communications. The proposed diversity antenna has four monopole radiators oriented in orthogonal directions to obtain polarisation diversity. The optically transparent nature is realised using a soda-lime substratum of size 50 × 50 mm2 coated with Transparent Conductive Oxides (TCO). The Aluminium Zinc Oxide (AZO) is sputtered on top of a Fluorine Tin Oxide (FTO) to enhance the material’s conductivity with dual-conductive layer. The fabricated MIMO antenna has a bandwidth of 10 GHz and functions in the entire UWB range (2 to 12 GHz). By incorporating concentric circles into the ground, high confinement between nearly located antenna elements is achieved. The antenna has a peak gain of 2.9 dBi as measured. The Envelope Correlation Coefficient (ECC) of the antenna in the entire Ultra-wideband (UWB) region attributed to the TCO material shows a very low correlation among the antenna elements. Because of diversity gain of the proposed vehicular antenna is ˃ 9.8 dB, it can also operate with low transmission power. The findings indicate that the antenna is pertinent for current intelligent vehicles that require multiple communications without aesthetic hindrance.

Joint Optimization of Trajectory and Node Access in UAV-Aided Data Collection System

With the continuous development of Internet of Things, data transmission presents an exponential rising trend. Due to the limited energy storage and low transmission power of sensor nodes, it is impossible to continuously transmit a large amount of collected data to the remote cloud center for a long time. To guarantee the data reliability and extend the lifetime of sensor nodes, we use unmanned aerial vehicle (UAV) assisted data collection for data transmission to improve the performance of the network. As each sensor node has a certain business requirement for unloaded data volume, the flight trajectory and node access scheme are jointly optimized to minimize the energy consumed by all the sensing nodes. First, a model regarding the minimization problem of the maximum energy consumption was constructed. To effectively solve this nonconvex problem, the block coordinate descent method and slack variable method are used to transform the original optimization problem into two subproblems: trajectory optimization problem and node access scheme optimization problem. Second, an algorithm is proposed using the successive convex approximation to jointly optimize the flight trajectory and node access scheme. This algorithm acquires the optimal node access scheme and UAV flight trajectory successively in each iteration. When the number of iterations is great enough, the minimum–maximum energy consumption of sensing nodes is gradually converged. The simulation results showed that in comparison with the basic UAV flight scheme, the proposed algorithm can effectively reduce the energy consumption of nodes and improve the data transmission rate, and meanwhile, this algorithm is characterized by favorable convergence and tolerable complexity.

Behavior of Centrifuged GFRP Poles Under Lateral Deflection

Centrifugal-manufactured GFRP pipes are widely used today as lighting and low-power transmission poles due to their lightweight, high electrical insulation, low cost, and corrosion resistance. Despite these advantages, GFRP poles suffer high deflection problems due to their low elastic and shear moduli values. In order to overcome this disadvantage, three techniques were suggested to control the lateral deflection of the GFRP poles: an extended internal steel stub, external steel angles, and internal steel bracing bars. The main objective of this study is to determine the optimum strengthening technique to improve the serviceability of GFRP poles in terms of lateral deflection according to ASTM D4923. An experimental research program containing five full-scale GFRP poles was carried out to determine the optimum strengthening technique and the effect of connectors opening near the base and compare it to previous research. The results indicated that flexural stiffness was increased by 44%, 66%, and 38% for the extended stub, steel angles, and bracing bars, respectively. Besides that, the reduction in flexural stiffness due to connector opening was about 8%. The measured deflections showed good matching with simplified mathematical calculations, and the division was about ±10%. The external steel angle technique showed the best efficiency in Stiffness behavior. Doi: 10.28991/CEJ-2023-09-06-07 Full Text: PDF

Development and Verification of an IoT-enabled Air Quality Monitoring System Based on Petri Nets

An internet of things (IoT) system for monitoring environmental parameters on campus has been successfully developed in this study. Various sensors are adopted in front of the IoT system for detecting air pollutants. The architecture of LongRange in Class C uses low-power and long-distance transmission technologies, which has been set up on the large campus so that the terminal equipment can reach a balance between downlink latency and battery life, making it the best communication protocol. In addition, this monitoring system uses the Petri net software tool to build a correct IoT platform based on the fundamental design process and to demonstrate the feasibility of the IoT system through simulation-based verification. Finally, the experimental results indicate that the IoT system for monitoring the environmental parameters on campus achieves the goal of an acceptable data transmission success rate of more than 95%. Thus, it can facilitate the air quality trends for policy making as well as the hazardous prediction and prevention.

DRL-Based Computation Offloading With Queue Stability for Vehicular-Cloud-Assisted Mobile Edge Computing Systems

Computation offloading is considered as a promising method to improve computation performance of Intelligent Vehicles (IVs), where IVs can offload resource-hungry applications to Mobile Edge Computing (MEC) servers. However, due to the dynamic environment of Intelligent Transportation Systems, it's challenging to develop an effective offloading scheme that ensures stable operation of the system. Furthermore, IVs only offload tasks to MEC servers or parked vehicles, how to take full advantage of resources in a random traffic flow is a main challenge. In this paper, we propose a vehicular-cloud-assisted MEC network in urban cities to fully explore the idle resources and ensure the stability of task queue. Specifically, we develop a novel virtual platform based on deep neural network that predicts vehicles trajectory and creates vehicular cloud to integrate computation resources. We then design a vehicular-cloud-assisted offloading scheme that aims to maximize task throughput in continuous time slots subject to multi-constraint. To address the coupling among multiple variables and different time slots, we put forward a lightweight framework to apply the Lyapunov optimization in combination with deep reinforcement learning. In particular, we apply Lyapunov drift-plus-penalty approach to decompose the initial problem into per-slot subproblems and control the long-term task queue stability. To further reduce the computation complexity, we decouple the subproblem into three processes, and the deep Q-network is put forward to solve it. Extensive simulations demonstrate that under different task arrivals, our proposed scheme can achieve the task queue stability within 10 time slots with a low transmission power.

RF-Self-Powered Sensor for Fully Autonomous Soil Moisture Sensing

Soil moisture monitoring and irrigation scheduling are essential parameters in farming efficiency. Internet-of-Things (IoT) technology is a promising solution for automating irrigation procedures and improving farming efficiency by removing human faults. In this article, a new method is introduced to measure soil moisture level along with providing energy to run a low-power transmitter as an alarm signal. A combination of a metamaterial perfect absorber (MPA) and two rectifiers that are designed at different frequencies specifies 5% and 25% soil moisture levels. The sensor monitors the soil moisture continuously without consuming energy. Once the soil moisture becomes 5% of the first rectifier starts working and provides 65 uW dc output, while the second rectifier is off. Increasing the soil moisture to 25%, the second rectifier creates 100 uW dc output when the first rectifier is off. The designed structure is fabricated on RO4003 in a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4 \times 4$ </tex-math></inline-formula> array. The measurement results are provided by performing a set of different experiments. Initially, the MPA’s absorption characteristics are validated facing different polarization and incident angles. Then, the sensing capability is proven by burying the proposed sensor under sand and measuring the dc outputs of rectifiers. A strong correlation between simulation and measurement results validates the design procedure.

A Low-Power Wireless System for Predicting Early Signs of Sudden Cardiac Arrest Incorporating an Optimized CNN Model Implemented on NVIDIA Jetson.

The survival rate for sudden cardiac arrest (SCA) is low, and patients with long-term risks of SCA are not adequately alerted. Understanding SCA's characteristics will be key to developing preventive strategies. Many lives could be saved if SCA's early onset could be detected or predicted. Monitoring heart signals continuously is essential for diagnosing sporadic cardiac dysfunction. An electrocardiogram (ECG) can be used to continuously monitor heart function without having to go to the hospital. A zeolite-based dry electrode can provide safe on-skin ECG acquisition while the subject is out-of-hospital and facilitate long-term monitoring. To the ECG signal, a low-power 1 μW read-out circuit was designed and implemented in our prior work. However, having long-term ECG monitoring outside the hospital, i.e., high battery life, and low power consumption while transmission and reception of ECG signal are crucial. This paper proposes a prototype with a 10-bit resolution ADC and nRF24L01 transceivers placed 5 m apart. The system uses the 2.4 GHz worldwide ISM frequency band with GFSK modulation to wirelessly transmit digitized ECG bits at 250 kbps data rate to a physician's computer (or similar) for continuous monitoring of ECG signals; the power consumption is only 11.2 mW and 4.62 mW during transmission and reception, respectively, with a low bit error rate of ≤0.1%. Additionally, a subject-wise cross-validated, three-fold, optimized convolutional neural network (CNN) model using the Physionet-SCA dataset was implemented on NVIDIA Jetson to identify the irregular heartbeats yielding an accuracy of 89% with a run time of 5.31 s. Normal beat classification has an F1 score of 0.94 and a ROC score of 0.886. Thus, this paper integrates the ECG acquisition and processing unit with low-power wireless transmission and CNN model to detect irregular heartbeats.

Comparative Study about Dimensional Accuracy and Surface Finish of Constant-Breadth Cams Manufactured by FFF and CNC Milling

In this work, the design, manufacture and measurement process of constant-breadth cams is presented. The motion law of the cam was designed by means of Bézier curves and the corresponding design desmodromic constraints. The cams were manufactured in two different materials employing two different processes: PLA cams with fused filament fabrication (FFF) and aluminium cams with computer numerical control (CNC) milling. The main aim of this work is to compare both types of cams regarding dimensional accuracy and surface finish, in order to evaluate if it would be possible to temporally replace a metallic cam with a plastic one during the repair of the first one. Dimensions were measured with micrometres and surface roughness with a contact roughness meter. The results show that, in diametral dimensions, similar dimensional error values were obtained for both the 3D-printed and the machined cams. However, in longitudinal dimensions, whose direction is perpendicular to the 3D-printed layers, the 3D-printed cams showed higher dimensional error than the machined ones. The average roughness Ra in the 3D-printed cams was 20 times higher than in the milled cams. According to the results, it would be recommended to temporally replace metallic cams with plastic ones in applications of low-power transmission. Given that in the literature little information is available about the measurement of 3D-printed desmodromic cams, this work will contribute to the study and analysis of this kind of 3D printed mechanism.

Enhancing Secrecy Performance for STAR-RIS NOMA Networks

Simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) is becoming a prospective technology in realizing extremely low power transmission and seamless coverage for the sixth generation (6G) wireless communication era. Motivated by this, we study the secrecy performance of the STAR-RIS assisted non-orthogonal multiple access (NOMA) networks. To be more practical, we assume that all nodes suffer from residual hardware impairments (RHIs). To characterize the performance of the considered network, the analytical expressions of the secrecy outage probability (SOP) for NOMA users over the Nakagami- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$m$</tex-math></inline-formula> fading channels are derived. Meanwhile, the asymptotic behaviors of SOP at high signal-to-noise ratio (SNR) are also studied. The numerical results show that: 1) The existence of the RHIs reduces the secrecy performance of the network under consideration. 2) The increase in the number of configurable elements <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$K$</tex-math></inline-formula> will improve the system secrecy performance.

FPGA-Based Tactile Sensory Platform with Optical Fiber Data Link for Feedback Systems in Prosthetics

In this paper, we propose and validate a tactile sensory feedback system for prosthetic applications based on an optical communication link. The optical link features a low power and wide transmission bandwidth, which makes the feedback system suitable for a large number and variety of tactile sensors. The low-power transmission is derived from the employed UWB-based optical modulation technique. A system prototype, consisting of digital transmitter and receiver boards and acquisition circuits to interface 32 piezoelectric sensors, was implemented and experimentally tested. The system functionality was demonstrated by processing and transmitting data from the piezoelectric sensor at a 100 Mbps data rate through the optical link, measuring a communication energy consumption of 50 pJ/bit. The reported experimental results validate the functionality of the proposed sensory feedback system and demonstrate its real-time operation capabilities.

Ultra-Broadband NPE-Based Femtosecond Fiber Laser

A dissipative soliton mode-locked Yb-doped fiber laser is investigated experimentally and numerically from the point of view of generating ultra-broadband ultrashort pulses. An energy up to 2.2 nJ and a spectral bandwidth over 60 nm (at the −10 dB level) were obtained experimentally without dispersion compensation in the cavity. Almost a 100-fold compression coefficient has been achieved, so the resulting pulse duration was 149 fs. The numerical simulation has shown that a further scaling up to 3.5 nJ and a 100 nm spectral bandwidth is possible by reducing the low power transmission coefficient of the NPE-based SAM and increasing the amplification. At the same time, the tolerance of the SAM to a low power radiation is responsible for the transition to a multi-pulse operation regime.

Energy efficient route selection based on location and received signal strength in manatee

Mobile ad-hoc network is a grouping of movable nodes whose mutual effort creates the temporary infrastructure less topology. Nodes or devices communicate each other through radio range, intermediate devices and signal strength based mechanism. Mobile devices work with limited energy because mobile device contain battery that helps only to activate the devices. In previous related work, number of researcher enhanced the network life time by deploying energy consumption routing (ECR), Max-Min Battery cost routing (MMBCR) and many more techniques. In this paper, signal strength, transmission power requirement and location based approach is applied that helps to increase the reliability of the network with low overhead. Node locations are calculated through relative coordinate based mechanism. Signal strength is inversely proportional to location of nodes. It means signal strength is higher if node location is near, and on the other end, lower is the signal strength if far is the location of the node. Source to receiver path are selected on the basis of near node and higher signal strength and low transmission power, which increase the network performance in every aspect of network parameters. The proposed work is simulated through network simulator-2. Simulated result gives the higher data sends and receives rate and also calculates energy used, residual energy of network, receiving signal strength of each node, and node location in every discrete time interval.

X-Band CMOS Rectifier With 4% Efficiency at −35 dBm for Wireless Power Transmission

This paper proposes a radio frequency (RF) rectifier topology for low-power wireless power transmission (WPT) applications in the X band. The rectifier consists of a biased PMOS pair and is matched to the RF signal source impedance using a PCB transmission line (TL) matching network. It is demonstrated that a clever optimization of the bias voltage enables the rectifier to achieve greater sensitivity and efficiency than previous works at X band. The rectifier was designed in a 45 nm silicon-on-insulator (SOI) process and operates at a frequency of 9.64 GHz. It achieves a power conversion efficiency (PCE) of 4% and 46% at power levels of −35 dBm and −10 dBm, respectively.

Design and Development of a Low-Power Wireless MEMS Lead-Free Piezoelectric Accelerometer System

In this paper, a complete 3-D integrated sensing system intended for practical applications was presented on a PCB board, starting with lead-free piezoelectric films deposited using an RF sputtering system, a MEMS structure design/simulation, device fabrication, and a signal processing chip design including charge-to-voltage transformation, signal amplification, 60-Hz noise rejection, and low-power RF wireless transmission chip for remote monitoring. Both the signal processing chips and the RF wireless transmitter chips were manufactured using the TSMC CMOS process. The piezoelectric coefficient d33 was measured as 27.21pm/V of the proposed MLZO (ZnO: Li doped Mg) films. To meet the frequency specifications of industrial applications, the ring-structure devices with a 7730-Hz resonance frequency were designed using ANSYS simulation software. There was only a 0.39% deviation as compared to the simulation results with the actual experimental data. The measurement results of the proposed system showed that the acceleration detection range was approximately 137 mV/g(p-p). The voltage-controlled oscillator adopted in the wireless transmitter chip had a four-leaf clover structure inductor with two symmetrical axes resulting in better suppression of magnetic field radiation. Finally, this system was applied to industrial spindles, and the normal and abnormal operation information of spindles was successfully and wirelessly monitored.

Mechanisms of ensuring the accuracy and reliability of data transmission over a radio channel using relay technology and their implementation on transceivers with LoRa modulation

The article is devoted to a detailed description of the algorithms of the operation of the relay-race data transmission system over a radio channel, which ensure high reliability of transporting the results of monitoring the operation of extended objects to the central control panel. The feature of the system is operation at a low power level of transmitters, energy efficiency, which ensures a long-term operation without maintenance, the ability to replace failed elements quickly without stopping the entire system, mobility — quick installation and start-up of the system. Energy efficiency and operation of the radio channel with a low transmitter power level is ensured by the use of SX 1276 (LoRa) transceivers. The accuracy and reliability of data transmission is ensured by original algorithms, which are described in the paper. In the relay data transmission system, it is possible to use up to 255 relay nodes with their installation at a distance of up to 4 km from each other. Two options of building a system with relay-race transmission have been developed: a system with a simple handover, a system with transmission «Through one». The second option provides more reliable data transfer and higher probability of uptime. With the number of relay nodes equal to 50, the probability of failure-free operation of a simple system is 0.268, and for the system with «Through one» transmission is 0.985.

МЕТОД ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ КЕРУВАННЯ ЕНЕРГЕТИЧНИМ ПОТЕНЦІАЛОМ ЗАХИЩЕНИХ РАДІОЛІНІЙ ТЕРАГЕРЦОВОГО ДІАПАЗОНУ З ВИКОРИСТАННЯМ ШТУЧНОГО ІНТЕЛЕКТУ

The growth of large volumes of information flows encourages the development of transmission and reception systems in the very high frequency range to ensure effective control of IR-UWB radio links of terahertz signals based on machine learning algorithms and neural networks, taking into account energy saving. For this purpose, the article proposes an algorithm for tracking a multipath signal of a system for receiving signals from spatially separated low-power transmitters, a feature of which is the refinement in the process of tracking the time positions of the components and their number. A feature of the developed algorithm is the use of the wavelet transform to obtain the input image of the neural network. A structural and functional model for constructing a receiving system for IR-UWB signals in the very high frequency range with intelligent control elements is proposed, which is based on separate control planes and physical infrastructure for automatic and operational control of the process of sharing physical infrastructure resources and artificial intelligence methods. Unlike existing models of IR-UWB receiving systems for terahertz signals, it provides protocol and infrastructure data collection for intelligent algorithms. The presented physical infrastructure has a training and optimization module that involves the use of an existing simulation model of a radio link in the terahertz range from 0.11 to 0.17 terahertz to test intelligent algorithms for controlling the energy potential of IR-UWB radio links. The developed data collection algorithm involves monitoring the state of the blocks of the receiving complex for rational data collection using the change in the values of both the Euclidean distance metrics and the metrics of functional technical parameters in relation to the number of clusters.

Design of an Innovative Wireless Left Ventricular Assist Device Driven by either Extracorporeal Magnets or an Intracorporeal Battery Pack.

This study aimed to design a new wireless left ventricular assist device (LVAD) that solved the driveline problem of current LVADs and the heat problem of the transcutaneous energy transfer system (TETS). Our new wireless LVAD consisted of two blood pumps capable of driving using extracorporeal magnets and an intracorporeal battery pack. When one pump was driven, the other pump was stopped. The battery pack was wirelessly and slowly charged using TETS with low-power transmission, whereas the magnetic pump was driven wirelessly by extracorporeal magnets. We demonstrated the feasibility of our system in a bench-top durability test for 7 days. The distance between the extracorporeal magnets and the magnetic pump was 27.5 mm. Our LVAD system had steadily provided sufficient pressure and flow volume (approximately 108 mmHg and 5.0 L/min, respectively) to the test loop for 7 days. Although loss of synchronism occurred once during the test, it recovered within a few minutes. The results demonstrate the feasibility of the proposed wireless LVAD system. Further technical improvements are required in our system, such as downsizing the electric devices inside the body, to conduct an in vivo test for the next step.