Wireless Electronic Devices Research Articles

A survey on M2M systems for mHealth: a wireless communications perspective.

In the new era of connectivity, marked by the explosive number of wireless electronic devices and the need for smart and pervasive applications, Machine-to-Machine (M2M) communications are an emerging technology that enables the seamless device interconnection without the need of human interaction. The use of M2M technology can bring to life a wide range of mHealth applications, with considerable benefits for both patients and healthcare providers. Many technological challenges have to be met, however, to ensure the widespread adoption of mHealth solutions in the future. In this context, we aim to provide a comprehensive survey on M2M systems for mHealth applications from a wireless communication perspective. An end-to-end holistic approach is adopted, focusing on different communication aspects of the M2M architecture. Hence, we first provide a systematic review of Wireless Body Area Networks (WBANs), which constitute the enabling technology at the patient's side, and then discuss end-to-end solutions that involve the design and implementation of practical mHealth applications. We close the survey by identifying challenges and open research issues, thus paving the way for future research opportunities.

A novel heart sound activity detection framework for automated heart sound analysis

In automated heart sound analysis and diagnosis, a set of clinically valued parameters including sound intensity, frequency content, timing, duration, shape, systolic and diastolic intervals, the ratio of the first heart sound amplitude to second heart sound amplitude (S1/S2), and the ratio of diastolic to systolic duration (D/S) is measured from the PCG signal. The quality of the clinical feature parameters highly rely on accurate determination of boundaries of the acoustic events (heart sounds S1, S2, S3, S4 and murmurs) and the systolic/diastolic pause period in the PCG signal. Therefore, in this paper, we propose a new automated robust heart sound activity detection (HSAD) method based on the total variation filtering, Shannon entropy envelope computation, instantaneous phase based boundary determination, and boundary location adjustment. The proposed HSAD method is validated using different clean and noisy pathological and non-pathological PCG signals. Experiments on a large PCG database show that the HSAD method achieves an average sensitivity (Se) of 99.43% and positive predictivity (+P) of 93.56%. The HSAD method accurately determines boundaries of major acoustic events of the PCG signal with signal-to-noise ratio of 5dB. Unlike other existing methods, the proposed HSAD method does not use any search-back algorithms. The proposed HSAD method is a quite straightforward and thus it is suitable for real-time wireless cardiac health monitoring and electronic stethoscope devices.

Systematic Analysis on Power Consumption in Conventional Cmos, Multiplexer Based and Hybrid Adder

There has been a rapid increase in the popularity of portable and wireless electronic devices, like laptop computers, portable video players cellular phones, which rely on embedded digital signal processors. Since the desire is to design digital systems at best performance without power sacrifices, the need for high performance and low power multipliers is inevitable. Since multiplication is one of the most critical operations in many computational systems, Multipliers are in fact complex adder arrays. In this paper we performed a comparative analysis on power consumption in three different adders, each offering different advantages and having tradeoffs in terms of circuit complexity and power consumption. The 28 Transistor full adder is the pioneer CMOS traditional adder circuit. Which is the one which consume more power when compare to other two adder, the number of transistors required for conventional CMOS adder is 28. Recently, it has been proved that the multiplexer-based multiplier outperforms the modified Booth multiplier both in speed and power dissipation by 13% to 26%, due to small internal capacitance. After analyzing the performance characteristics of conventional multiplier types, it is observed that the one designed using multiplexer-based multiplication algorithm is more advantageous, especially when the size of the multiplied numbers is small. The number of transistors required for multiplexer based adder is 16. In order to achieve optimal power savings at smaller geometry sizes, we proposed a heuristic approach known as hybrid adder models. The hybrid adder models which consume low power among all three adder and the number of transistors required is 12. As an added advantage there will be no path from one voltage level (VDD) to the other (GND).The elimination of the direct path to the ground removes the short circuit power component for the adder module. This reduces the total energy consumed in the circuit and making it an energy efficient design. The SERF adder is not only energy efficient but also area efficient due to its low transistor count.

Wireless Public Key Infrastructure for Mobile Phones

Mobile devices play an important role in the wireless network environment for providing different services over internet. The business transactions over wireless electronic devices are not secure and hence the messages are prone to be intercepted and modified by an intruder. So, devices supporting wireless internet must be guaranteed at the same level of security as the wired network. PKI (Public Key Infrastructure) used in the wired environment is not suitable for wireless environment because of the less powerful processor and small memory. This arises a need for the development of a Wireless Public Key Infrastructure (WPKI) that provides the similar security level as the wired PKI suitable for mobile phone. In this paper, a discussion of public key infrastructure and an experimental set up for Wireless Public key Infrastructure for mobile phones are made.

A hash-based RFID security protocol for strong privacy protection

RFID (Radio Frequency Identification) tags are small, wireless electronic devices that help identify objects and people. Privacy protection and integrity assurance become rather crucial in the RFID systems, because these RFID tags may have a wide transmission range, making them subject to unauthorized scanning by malicious readers and various other attacks. Hence, Ha et al. proposed an RFID protocol and proved that their protocol can provide the forward privacy service. However, in this paper, it is shown that an attacker can track a target tag by observing unsuccessful previous session of the tag. That is, Ha et al.'s RFID protocol fails to provide the forward privacy protection as claimed. Therefore, to overcome the privacy weaknesses of Ha et al.'s RFID protocol, an RFID protocol based on the cryptographic hash functions is proposed. Moreover, the proposed RFID protocol is evaluated according to both the privacy attribute and the implementation performance.

A magnetoelectric-based broadband vibration energy harvester for powering wireless sensors

Scavenging vibration energy directly from environments is an attractive technique for potentially powering small and/or wireless electronic devices in a smart structure and system. In this paper, a novel broadband vibration energy harvester is designed and analyzed, which consists of three cantilever beams, two magnetoelectric (ME) transducers and a magnetic circuit. A theoretical model is developed to analyze the effects of the structure parameters on the frequency response and the electrical output for achieving the optimal vibration energy harvesting performances. A prototype is fabricated and tested. The experimental results show that the harvester has a bandwidth of 7.2 Hz and an average power of 0.21 mW at an acceleration of 0.2 g (with g=9.8 ms−2).

Harvesting ambient acoustic energy using acoustic resonators.

There is currently a high demand for the development of powering systems to supply electricity to small wireless electronic devices. This has led to various energy harvesting concepts aimed to harvest potential energy sources, such as solar, thermal, wind, and vibration/wave energies. Harvesting acoustic energy has been rarely investigated because of its lower energy density compared with other resources. Even though a single acoustic wave has the lowest energy density among the above candidates, sound is abundant in our everyday life and is currently wasted. Therefore, harvesting sound energy would be a good alternative to already existing other energy harvesters. In this work, a computational model for harvesting acoustic energy using a Helmholtz resonator will be presented. To convert acoustic energy to electricity, piezoelectric wires are placed inside a Helmholtz resonator. When an external sound excites the resonator at acoustic resonant frequencies, the amplified acoustic pressure is developed and generates the vibration motion of the piezoelectric wires resulting in electricity generation. Fundamental mechanisms coupling the electrical power generation by acoustic resonant behavior of Helmholtz resonators will be presented. The effects of geometries of Helmholtz resonators and piezoelectric wires on electricity generation have been studied numerically and will be presented.

Broadband dual planar inverted F-antenna for wireless local area networks/worldwide interoperability for microwave access and lower-band ultra wideband wireless applications

An extension of the planar inverted F-antenna (PIFA) concept is proposed, combining two such antennas (one of them fed parasitically) to extend the usable bandwidth to cover the WiFi wireless local area network, worldwide interoperability for microwave access and lower-band ultra wideband spectra. The broad impedance bandwidth is achieved by combining a driven slotted PIFA, having bandwidth-enhanced rectangular strip feed, with a parasitic inverted F-shaped element, hence describable as a dual PIFA. The geometry parameters of these two radiators are selected to enhance the impedance bandwidth and hence to encompass the entire required set of operating frequency bands. The overall optimised dimensions of the antenna are 30 mm 15 mm 8 mm, thus making it compatible with installation on portable wireless electronic devices. The results show that the proposed antenna can achieve a gain between 2.0 and 4.0 dBi across the entire impedance bandwidth 2.4 6.2 GHz (i.e. 88.4 relative bandwidth) for a reflection coefficient of | S 11 | <; 10 dB. The radiation patterns of the antenna show low-gain broad-beam coverage, as is essential for a wireless electronic device. Computed and experimental results are compared and are shown to be in satisfactory agreement.

Compact, printed mobile-unit antenna for 2.4 and 5 GHz WLAN applications

A simple yet effective, printed mobile-unit antenna aimed at providing dual-WLAN-band operation in the 2.4 and 5 GHz bands and with a small form factor is presented.The antenna comprises a folded monopole and a small antenna ground, all printed in a single-layered, FR4 substrate with the overall dimensions 8 mm × 25 mm. The frequency ratio of the dual-resonant (the upper over the lower) modes can easily be manipulated by adjusting the antenna tuning portion. In addition, the antenna can be fed by utilizing a common mini-coaxial cable, allowing it to be flexibly deployed inside versatile wireless electronic devices as an internal antenna. Details of a design prototype are described and discussed in the article. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2648–2653, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25561

Energy Harvesting From Human and Machine Motion for Wireless Electronic Devices

Energy harvesting generators are attractive as inexhaustible replacements for batteries in low-power wireless electronic devices and have received increasing research interest in recent years. Ambient motion is one of the main sources of energy for harvesting, and a wide range of motion-powered energy harvesters have been proposed or demonstrated, particularly at the microscale. This paper reviews the principles and state-of-art in motion-driven miniature energy harvesters and discusses trends, suitable applications, and possible future developments.

Prolog to: Energy Harvesting From Human and Machine Motion for Wireless Electronic Devices

Prolog to: Energy Harvesting From Human and Machine Motion for Wireless Electronic Devices

Proposal and Implementation Study of Forwarding Method for Urgent Messages on a Wireless Sensor Network

Recent advances in wireless technologies and electronic devices have enabled the development of low-cost and large-scale wireless sensor networks. Many recent studies have targeted wireless sensor networks, but forwarding messages while satisfying both delay and reliability constraints remains an unsatisfied goal. Although most existing proposals aim at resiliency in multi-hop networks, improvement of network performance such as throughput and latency, and load balancing, supporting multiple forwarding strategies satisfying various demands is not discussed. We propose a forwarding method for messages with delay and reliability constraints on a single wireless sensor network. We evaluate message loss rate by using computer simulation and by implementing the proposed method on actual sensor nodes. Our results show that the proposed method achieves lower message loss rate for messages with delay and reliability constraints than that for best-efforts messages on a network with error-prone wireless links.