Low-power Solution Research Articles

A Survey on the Security Challenges of Low-Power Wireless Communication Protocols for Communicating Concrete in Civil Engineerings.

With the increase in low-power wireless communication solutions, the deployment of Wireless Sensor Networks is becoming usual, especially to implement Cyber-Physical Systems. These latter can be used for Structural Health Monitoring applications in critical environments. To ensure a long-term deployment, battery-free and energy-autonomous wireless sensors are designed and can be powered by ambient energy harvesting or Wireless Power Transfer. Because of the criticality of the applications and the limited resources of the nodes, the security is generally relegated to the background, which leads to vulnerabilities in the entire system. In this paper, a security analysis based on an example: the implementation of a communicating reinforced concrete using a network of battery-free nodes; is presented. First, the employed wireless communication protocols are presented in regard of their native security features, main vulnerabilities, and most usual attacks. Then, the security analysis is carried out for the targeted implementation, especially by defining the main hypothesis of the attack and its consequences. Finally, solutions to secure the data and the network are compared. From a global point-of-view, this security analysis must be initiated from the project definition and must be continued throughout the deployment to allow the use of adapted, updatable and upgradable solutions.

A Low-Cost, Low-Power, Multisensory Device and Multivariable Time Series Prediction for Beehive Health Monitoring.

We present a custom platform that integrates data from several sensors measuring synchronously different variables of the beehive and wirelessly transmits all measurements to a cloud server. There is a rich literature on beehive monitoring. The choice of our work is not to use ready platforms such as Arduino and Raspberry Pi and to present a low cost and power solution for long term monitoring. We integrate sensors that are not limited to the typical toolbox of beehive monitoring such as gas, vibrations and bee counters. The synchronous sampling of all sensors every 5 min allows us to form a multivariable time series that serves in two ways: (a) it provides immediate alerting in case a measurement exceeds predefined boundaries that are known to characterize a healthy beehive, and (b) based on historical data predict future levels that are correlated with hive's health. Finally, we demonstrate the benefit of using additional regressors in the prediction of the variables of interest. The database, the code and a video of the vibrational activity of two months are made open to the interested readers.

EEG-Over-BLE: A Low-Latency, Reliable, and Low-Power Architecture for Multichannel EEG Monitoring Systems

Recent enhancements in the field of wireless communication protocols have led to the development of several wearable devices and sensor networks suitable for health monitoring and diagnostic purposes. Nevertheless, new low-power solutions are still needed for enabling long-term, comfortable and lightweight monitoring systems. This paper deals with EEG-over-BLE, a novel architecture for multi-channel electroencephalography (EEG), characterized by low power consumption. The proposed architecture relies on a low-power analog front-end for EEG signals and a system-on-chip that supports the Bluetooth 5.0 protocol. Moreover, a near-lossless EEG compression algorithm and a simple channel encoding scheme are introduced in the proposed architecture in order to reduce energy consumption and improve network performance. Detailed investigations were carried out in order to evaluate the performance of the proposed architecture. In particular, simulation results and an analytical model on power consumption reported in this paper show that, when commercial small-form-factor batteries are used for power supply, the lifetime of a 64 channels EEG-over-BLE monitoring system is over 86 days. Moreover, the proposed architecture is highly reliable, achieving a packet loss rate lower than 0.1% and a latency below 35 ms, which is compliant with ISO/IEEE 11073 standard for medical device communications.

Next-Generation IoT Devices: Sustainable Eco-Friendly Manufacturing, Energy Harvesting, and Wireless Connectivity

This invited paper presents potential solutions for tackling some of the main underlying challenges toward developing sustainable Internet-of-things (IoT) devices with a focus on eco-friendly manufacturing, sustainable powering, and wireless connectivity for next-generation IoT devices. The diverse applications of IoT systems, such as smart cities, wearable devices, self-driving cars, and industrial automation, are driving up the number of IoT systems at an unprecedented rate. In recent years, the rapidly-increasing number of IoT devices and the diverse application-specific system requirements have resulted in a paradigm shift in manufacturing processes, powering methods, and wireless connectivity solutions. The traditional cloud-centering IoT systems are moving toward distributed intelligence schemes that impose strict requirements on IoT devices, e.g., operating range, latency, and reliability. In this article, we provide an overview of hardware-related research trends and application use cases of emerging IoT systems and highlight the enabling technologies of next-generation IoT. We review eco-friendly manufacturing for next-generation IoT devices, present alternative biodegradable and eco-friendly options to replace existing materials, and discuss sustainable powering IoT devices by exploiting energy harvesting and wireless power transfer. Finally, we present (ultra-)low-power wireless connectivity solutions that meet the stringent energy efficiency and data rate requirements of future IoT systems that are compatible with a batteryless operation.

Low Power Analog Processing for Ultra-High-Speed Receivers With RF Correlation

Ultra-high-speed data communication receivers (Rxs) conventionally require analog digital converters (ADC)s with high sampling rates which have design challenges in terms of adequate resolution and power. This leads to ultra-high-speed Rxs utilising expensive and bulky high-speed oscilloscopes which are extremely inefficient for demodulation, in terms of power and size. Designing energy-efficient mixed-signal and baseband units for ultra-high-speed Rxs requires a paradigm approach detailed in this paper that circumvents the use of power-hungry ADCs by employing low-power analog processing. The low-power analog Rx employs direct-demodulation with RF correlation using low-power comparators. The Rx is able to support multiple modulations with highest modulation of 16-QAM reported so far for direct-demodulation with RF correlation. Simulations using Matlab, Simulink R2020a® indicate sufficient symbol-error rate (SER) performance at a symbol rate of 8 GS/s for the 71 GHz Urban Micro Cell and 140 GHz indoor channels. Power analysis undertaken with current analog, hybrid and digital beamforming approaches requiring ADCs indicates considerable power savings. This novel approach can be adopted for ultra-high-speed Rxs envisaged for beyond fifth generation (B5G)/sixth generation (6G)/ terahertz (THz) communication without the power-hungry ADCs, leading to low-power integrated design solutions.

Review on multi bit flip-flop enhanced shift register: A low power solution for UART

This paper details the Verilog HDL- based design of UART modules. Developing UART with a shift register utilizing multibit flip-flops proves to be pragmatic strategy for contemporary VLSI circuits. This work supports not only asynchronous and serial communication but also aligns with essential objectives of minimizing power consumption and reducing overall circuit area. Such integration enhances data transmission efficiency while meeting crucial design considerations in modern electronics

A 128-kbit GC-eDRAM With Negative Boosted Bootstrap Driver for 11.3× Lower-Refresh Frequency at a 2.5% Area Overhead in 28-nm FD-SOI

Gain-cell embedded DRAM (GC-eDRAM) is a high-density logic-compatible alternative to conventional static random-access memory (SRAM) and embedded DRAM (eDRAM). However, GC-eDRAM suffers from a reduced data retention time (DRT) at deeply-scaled process nodes, leading to frequent power-hungry refresh operations. In order to reduce the refresh overhead, GC-eDRAM macros utilize external assist voltages which improve the bitcell write-ability, leading to an enhanced DRT. However, the requirement for external analog supply voltages creates additional overhead and is often impractical in the design of compact systems-on-chip (SoC). This work presents an on-chip write-assist technique implemented with a negative boosted bootstrap driver which generates the required wordline boosting on-chip without external components. The proposed circuitry is integrated compactly inside the GC-eDRAM macro to provide an area-efficient low-power solution which improves the bitcell’s write-ability and reduces its refresh requirement. A 128-kbit GC-eDRAM macro utilizing the proposed boosting circuitry has been fabricated in a 28-nm FD-SOI technology, demonstrating an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$11.3\times $ </tex-math></inline-formula> DRT improvement at only 2.5% area overhead.

Angle of Arrival and Centimeter Distance Estimation on a Smart UWB Sensor Node

Accurate and low-power indoor localization is becoming more and more of a necessity to empower novel consumer and industrial applications. In this field, the most promising technology is based on Ultra-Wideband (UWB) modulation; however, current UWB positioning systems do not reach centimeter accuracy in general deployments due to multi-path and non-isotropic antennas, still necessitating several fixed anchors to estimate an object’s position in space. This paper presents an in-depth study and assessment of Angle of Arrival (AoA) UWB measurements using a compact, low-power solution integrating a novel commercial module with Phase Difference of Arrival (PDoA) estimation as integrated feature. Results demonstrate the possibility of reaching centimeter distance precision and 2.4° average angular accuracy in many operative conditions, e.g., in a 90° range around the center. Moreover, integrating the channel impulse response, the phase differential of arrival, and the point-to-point distance, an error correction model is discussed to compensate for reflections, multi-paths, and front-back ambiguity.

Low-Power Organic LED Fabricated by a Novel Solution-Based Process for Photoplethysmography Sensing

Power consumption level of electronic devices has been always considered as an important factor for a wide range of applications. In this study, a novel fabrication step, namely pre-drying, applicable to solution-based fabrication processes is proposed to minimize the overall power consumption of organic light-emitting diodes (OLEDs). The pre-dry step allows the solution to dwell on the substrate for a certain short time before the spin coater is turned on. It is experimentally shown that the pre-drying step for OLEDs with the hole transfer layer (HTL) of Poly (3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) can reduce the ohmic-loss by a factor of 2.41, in addition to reducing the turn-on voltage by 0.9 V and increasing the luminance 1.3 times at 15 V in comparison to the fabricated OLED without pre-drying step. To further minimize the power consumption of OLEDs, it is proposed to replace PEDOT:PSS with copper(I) thiocyanate (CuSCN) as HTL, which can be deposited by a solution fabrication process including the pre-drying step. A comparison among the fabricated OLEDs with the pre-dried HTLs made of CuSCN and PEDOT:PSS indicates that the generated luminance increases by a factor of 4.28 from 2.8 to 12 kcd/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for an identical voltage of 11 V. Due to the superior performance of the proposed OLED based on the pre-dried HTL of CuSCN, its behavior as a light source for photoplethysmography (PPG) sensing systems is surveyed. In this context, the PPG sensor is implemented in the form of a flexible-hybrid sensor system in which the fabricated OLED and a commercial photodiode are housed on a flexible substrate. Results confirm that the implemented flexible-hybrid PPG sensor operating in reflectance mode can acquire high quality PPG signals with relatively low power consumption and accurately estimate heart rate. The competency of the proposed OLED as a low-power solution for PPG sensor technology is highlighted by comparing its performance with the state of the art.

Performance Evaluation of C/C++, MicroPython, Rust and TinyGo Programming Languages on ESP32 Microcontroller

The rapid growth of the Internet of Things (IoT) and its applications requires high computational efficiency, low-cost, and low-power solutions for various IoT devices. These include a wide range of microcontrollers that are used to collect, process, and transmit IoT data. ESP32 is a microcontroller with built-in wireless connectivity, suitable for various IoT applications. The ESP32 chip is gaining more popularity, both in academia and in the developer community, supported by a number of software libraries and programming languages. While low- and middle-level languages, such as C/C++ and Rust, are believed to be the most efficient, TinyGo and MicroPython are more developer-friendly low-complexity languages, suitable for beginners and allowing more rapid coding. This paper evaluates the efficiency of the available ESP32 programming languages, namely C/C++, MicroPython, Rust, and TinyGo, by comparing their execution performance. Several popular data and signal processing algorithms were implemented in these languages, and their execution times were compared: Fast Fourier Transform (FFT), Cyclic Redundancy Check (CRC), Secure Hash Algorithm (SHA), Infinite Impulse Response (IIR), and Finite Impulse Response (FIR) filters. The results show that the C/C++ implementations were fastest in most cases, closely followed by TinyGo and Rust, while MicroPython programs were many times slower than implementations in other programming languages. Therefore, the C/C++, TinyGo, and Rust languages are more suitable when execution and response time are the key factors, while Python can be used for less strict system requirements, enabling a faster and less complicated development process.

PACT

The food and drug industry is facing the need to monitor the quality and safety of their products. This has made them turn to low-cost solutions that can enable smart sensing and tracking without adding much overhead. One such popular low-power solution is backscatter-based sensing and communication system. While it offers the promise of battery-less tags, it does so at the cost of a reduced communication range. In this work, we propose PACT - a scalable communication system that leverages the knowledge asymmetry in the network to improve the communication range of the tags. Borrowing from the backscatter principles, we design custom PACT Tags that are battery-less but use an active radio to extend the communication range beyond standard passive tags. They operate using the energy harvested from the PACT Source. A wide-band Reader is used to receive multiple Tag responses concurrently and upload them to a cloud server, enabling real-time monitoring and tracking at a longer range. We identify and address the challenges in the practical design of battery-less PACT Tags using an active radio and prototype them using off-the-shelf components. We show experimentally that our Tag consumes only 23μJ energy, which is harvested from an excitation Source that is up to 24 meters away from the Tag. We show that in outdoor deployments, the responses from an estimated 520 Tags can be received by a Reader concurrently while being 400 meters away from the Tags.

SMART GLASSES FOR BLIND PEOPLE

smart glass is a wearable device , this device is used for blind people and also for the night blindness , Their life and activities are greatly restricted by loss of blindless.they normally travel by using their memory power from one place to other place. The main objective of the present work is to develop a low cost, reliable, portable, user friendly, low power and robust solution for smooth navigation. . It has an in-built sensor in which it spreads ultrasonic waves in the direction the person is going by scanning at most 5-6 meters of 30o range. As soon as the obstacle is detected by the sensor ,detects it and sends the message to the device which generates an automated voice in the earphone and vibrates with the help of vibrators connected to the person's ear.due to this they can over come from the problems and they can build the confidence. KEY WORDS :- Ultra sonic sensors , raspberry pi , blind people buzzers .

Interference Mitigation and Decoding Through Gateway Diversity in LoRaWAN

Long Range (LoRa) represents an efficient low power solution for the Internet of Things. Specifically, LoRa defines a physical layer technology, while access control and network issues are handled by the LoRaWAN protocol. Channel access is essentially unslotted ALOHA, so LoRaWAN performance suffer from packet collision events. Such problem becomes more penalizing in dense network scenarios, where the large number of devices simultaneously connected makes the collision probability significantly grow. The largest part of solutions proposed to overcome LoRaWAN inefficiency is oriented to collision avoidance. Differently, we firstly present an algorithm for mitigating the interference among superposing LoRa signals, allowing collided packets to be detected anyway. Then, we propose a novel combining mechanism, implemented at the LoRaWAN network server, that exploits the information carried by the same packet, but received by different gateways, to achieve a more robust decoding. Hence, packet detection is reliably performed even in the presence of interference, thus reducing the need of retransmission and providing energy saving for end devices. Furthermore, simulation results show that the proposed solutions allow the end users to transmit exploiting low spreading factors, thus reducing the channel use that will be fundamental when dealing with larger scale network scenarios.

Overcome the future environmental challenges through sustainable and renewable energy resources

The necessity to achieve global sustainability and renewable energy resources to overcome the threat of climate change has led to unparalleled social and economic alterations ubiquitous throughout the world. The environment surrounding pollution correlated with global warming is essential to technological advances for developing energy resources. Renewable and sustainable energy resources are eco-friendly energy sources that transform heat directly into electrical energy. The transformation of the global energy system underway in various countries can play a predominant role in power sectors. It helps in establishing a low-power solution with high performance in advance. This review paper highlights technological feasibility within the economic activity of sustainable resources in various sectors. The sustainable resource would represent the world's most advanced technology and cost-effective global power transition pathway. The present status, prospects, and updated information about these energy resources have been discussed in detail. This review provides a recommendation on which energy would be suitable for electrical energy generation and would establish a green environment for the next generation to survive in the world.

A Fully Integrated 1.7mW Attention-Based Automatic Speech Recognition Processor

This brief presents a low-power attention-based automatic speech recognition (ASR) processor achieving real-time recognition capability. The proposed attention window algorithm, compact end-to-end neural-network topology, and efficient computation dataflow effectively minimize the hardware complexity and power consumption, enabling a fully integrated low-power ASR processor solution without the necessity of any off-chip memory resource. The proposed design techniques reduced 98.9% weight memory and 92.1% power consumption with minimal degradation of 2.24% in recognition accuracy. The proposed ASR processor operates at 100MHz with 1.7mW at 0.9V, demonstrating 2x and 1.68x performance improvements in speed and power, respectively, compared to the previous ASR designs that require additional supports of off-chip memory or external decoder.

Statistical Evaluation of Power-Aware Routing Protocols for Wireless Networks

Distributed wireless networks use low-power nodes, battery-powered routers, and base-station nodes. Routing strategies lose energy due to distance-dependent transmission and reception. Researchers design low-power routing solutions for wireless networks. Each technique has unique advantages, restrictions, and research options. Protocols vary in energy consumption, throughput, latency, packet delivery ratio (PDR), scalability, and computational complexity. Researchers can't choose ideal context-aware network models due to diverse performance measurements. This article addresses application-specific deployment strengths to reduce uncertainty. This discussion may help researchers choose context-specific routing models. This article compares power-aware routing model performance measures. This comparison may be used to construct routing models for low-delay, high-throughput, high PDR installations, etc. This paper proposes an algorithm rank score (ARS) with performance metrics. Network designers may employ high-ARS routing models to achieve performance balance over numerous assessments.

An energy-efficient single-cycle RV32I microprocessor for edge computing applications

With the advancement in the Internet of Things (IoT) and Wireless Sensor Node (WSN) applications computation on edge is preferred over computation on the cloud. However, due to limited resource availability in the edge environment, energy efficiency can be seen as the primary barrier in the growth of edge computing devices. In edge computing applications like wearable devices, forest monitoring systems, and other such applications, power is of utmost importance. The use of a complex, pipelined, general-purpose processor is redundant for such low-end applications and it leads to high power consumption. Hence, edge computing systems require low-power solutions while still maintaining a minimum performance level. In this work, an energy-efficient single-cycle RISC-V instruction set architecture (ISA) based RV32I processor is designed for low-end edge computing applications. The design incorporates base integer implementation of RISC-V ISA. The proposed computing system is designed using Verilog HDL and synthesized on Semi-conductor Laboratory (SCL) 180 nm CMOS process technology node. The synthesis tool reports power consumption of 14.7 mW at 50 MHz frequency with an area of 0.24 mm2. Though synthesis of this design reports area of 0.24 mm2, the design is taped out as a part of an available shuttle project where die size is fixed to 5 mm × 5 mm. The PNR (Place and Route) tool reports power consumption of 11.8 mW at an operating frequency of 40 MHz. A basic functional testing of proposed fabricated RV32I chip is carried out in laboratory experimental setup and results are presented. The comparison result shows that the proposed RV32I processor consumes 0.29 mW/MHz power which is less than state-of-the-art low-end processors. Hence, the proposed design is suitable for low-end edge computing applications.

Nanosecond photonic integrated multicast switch for low-latency optical wireless data center networks

Optical wireless data center networks (OW-DCNs), featuring no cable complexity, low latency, and high throughput, are highly attractive for the next generation of DCNs, while photonic integration provides a compact, low-power, and low-cost solution. In this Letter, we propose a novel, to the best of our knowledge, OW-DCN architecture using photonic integrated multicast switches (PIC-MCSs) to realize fast optical switching and multicast operation between top-of-the-rack switches (ToRs). By properly turning on/off the transmission channels of a semiconductor optical amplifier (SOA)-based PIC-MCS, the optical signals are directed to different target ToRs via arrayed waveguide grating routers (AWGRs) and free-space links. A 4×2 PIC-MCS with lossless multicast operation has been designed and fabricated. An OW-DCN of 4×4 interconnected racks has been experimentally demonstrated with the chip and a 4×4 AWGR. The results confirm the performance of low-latency switching, dynamic bandwidth reallocation, and WDM multicast transmission. Error-free operation at 10 Gb/s OOK with a power penalty of less than 1 dB is achieved, showing a negligible impact of cross talk on the PIC-MCS.

Analysis of time-weighted LoRa-based positioning using machine learning

Localization systems have gained attention owing to the paradigm shift from human-centric communication systems (1G to 4G) to the machine-to-machine architectures (5G and beyond). The commercial localization applications standardized for 5G systems have served as a precursor to the cardinality of positioning technologies in the next-generation communication systems. The stringent requirements of these use-cases have motivated researchers to propose novel architectures and techniques to develop scalable, accurate, reliable, robust, and low-power positioning and tracking systems. Low-power wide-area network (LPWAN) technologies have found their niche in the Internet-of-thing (IoT)-focused industrial and research communities, since they promise wide area coverage to many battery-operated devices. LoRaWAN, with regulatory features and high network density, has emerged as the widely adopted long-range, low-power solution for scheduled IoT applications. This paper explores the feasibility of LoRa technology for satellite navigation-independent positioning, using received signal strength indicator (RSSI) fingerprinting. We explore traditional path-loss models, machine learning and deep learning techniques to develop an accurate RSSI-to-distance mapping. We further use the analytically optimal model as the underlying ranging function for trilateration-based deterministic positioning. The results indicate that LoRa technology is a feasible alternate for fingerprinting-based positioning in line-of-sight and non-line-of-sight scenarios, with accuracies ranging from 6 to 15 m.

Wireless Information and Power Transfer for IoT: Pulse Position Modulation, Integrated Receiver, and Experimental Validation

Simultaneous wireless information and power transfer (SWIPT) has emerged as a viable technique to energize and connect low-power autonomous devices and enable future Internet of Things (IoT). A major challenge of SWIPT is the energy consumption of the receiver of such low-power devices. An attractive low-power solution consists of an integrated information decoder (ID) and energy harvester (EH) architecture for SWIPT receiver (IntRx) where the received radiofrequency (RF) signal is first rectified before being used for information decoding. Such architecture eliminates the need for energy-consuming RF components, such as local oscillators and mixers. This article proposes a novel modulation and demodulation method for the IntRx SWIPT architecture based on pulse position modulation (PPM) where information is encoded in the position of the pulse. The new method transmits high amplitude pulses to increase the peak-to-average power ratio (PAPR) of the transmit signal and exploits the EH’s nonlinearity so as to boost the harvested dc power. Simultaneously, the information can be decoded from the rectifier signal by simply finding the position of the pulse in a certain symbol duration. We have analyzed both the information and the power transfer performance of the newly proposed PPM for IntRx SWIPT theoretically, numerically, and experimentally. To that end, we have established a SWIPT system testbed in an indoor environment by prototyping a base station to transfer information-power signal and the IntRx SWIPT receiver, including ID and EH blocks. The performance evaluation of the PPM was carried out in various conditions, and the results have been compared and contrasted to conventional signals. Theoretical, numerical, and experimental results highlight the significant benefits of the proposed PPM scheme to enhance the power transfer performance and operate information decoding with low-power consumption.