Wireless body sensor networks for health-monitoring applications

This is an author-created, un-copyedited version of an article accepted for publication in Physiological Measurement. The publisher is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://dx.doi.org/10.1088/0967-3334/29/11/R01

Design, Implementation, and Performance Evaluation of a Flexible Low-Latency Nanowatt Wake-Up Radio Receiver

Wireless sensor networks (WSNs) have received significant attention in recent years and have found a wide range of applications, including structural and environmental monitoring, mobile health, home automation, Internet of Things, and others. As these systems are generally battery operated, major research efforts focus on reducing power consumption, especially for communication, as the radio transceiver is one of the most power-hungry components of a WSN. Moreover, with the advent of energy-neutral systems, the emphasis has shifted toward research in microwatt (or even nanowatt) communication protocols or systems. A significant number of wake-up radio receiver (WUR) architectures have been proposed to reduce the communication power of WSN nodes. In this work, we present an optimized ultra-low power (nanowatt) wake-up receiver for use in WSNs, designed with low-cost off-the-shelf components. The wake-up receiver achieves power consumption of 152 nW (with-32 dBm sensitivity), sensitivity up to-55 dBm (with maximum power of 1,2 μW), latency from 8 μs, tunable frequency, and short commands communication. In addition, a low power solution, which includes addressing capability directly in the wake-up receiver, is proposed. Experimental results and simulations demonstrate low power consumption, functionality, and benefits of the design optimization compared with other solutions, as well as the benefits of addressing false positive (FP) outcomes reduction

Intelligent Routing Metric for Wireless Body Area Networks

Routing in Wireless Body Area Networks (WBANs) is a critical requirement due to its dynamic behaviour. This paper proposes an intelligent framework for link cost evaluation. A suitable Quality of Service (QoS) parameters based function has been proposed. The sensors in WBANs would be capable of computing the Link Cost (LC) function based upon the current values of QoS parameters: throughput, delay of the link and residual energy of the sensor. A fuzzy logic based system is proposed at the sensor to evaluate the LC. Nodes of architecture evaluate a set of possible paths between source-terminal pairs. This LC is then used to evaluate the suitable path for the routing

Energy harvesting methods for transmission lines: a comprehensive review

Humanity faces important challenges concerning the optimal use, security, and availability of energy systems, particularly electrical power systems and transmission lines. In this context, data-driven predictive maintenance plans make it possible to increase the safety, stability, reliability, and availability of electrical power systems. In contrast, strategies such as dynamic line rating (DLR) make it possible to optimize the use of power lines. However, these approaches require developing monitoring plans based on acquiring electrical data in real-time using different types of wireless sensors placed in strategic locations. Due to the specific conditions of the transmission lines, e.g., high electric and magnetic fields, this a challenging problem, aggravated by the harsh outdoor environments where power lines are built. Such sensors must also incorporate an energy harvesting (EH) unit that supplies the necessary electronics. Therefore, the EH unit plays a key role, so when designing such electronic systems, care must be taken to select the most suitable EH technology, which is currently evolving rapidly. This work reviews and analyzes the state-of-the-art technology for EH focused on transmission lines, as it is an area with enormous potential for expansion. In addition to recent advances, it also discusses the research needs and challenges that need to be addressed. Despite the importance of this topic, there is still much to investigate, as this area is still in its infancy. Although EH systems for transmission lines are reviewed, many other applications could potentially benefit from introducing wireless sensors with EH capabilities, such as power transformers, distribution switches, or low- and medium-voltage power lines, among others.This research was funded by Ministerio de Ciencia e Innovación de España, grant number PID2020-114240RB-I00 and by the Generalitat de Catalunya, grant number 2017 SGR 967.Peer ReviewedPostprint (author's final draft

RF Energy Harvesting Wireless Communication: RF Environment, Device Hardware and Practical Issues

Radio frequency (RF) based wireless power transfer provides an attractive solution to extend the lifetime of power-constrained wireless sensor networks. Through harvesting RF energy from surrounding environments or dedicated energy sources, low-power wireless devices can be self-sustaining and environment-friendly. These features make the RF energy harvesting wireless communication (RF-EHWC) technique attractive to a wide range of applications. The objective of this article is to investigate the latest research activities on the practical RF-EHWC design. The distribution of RF energy in the real environment, the hardware design of RF-EHWC devices and the practical issues in the implementation of RF-EHWC networks are discussed. At the end of this article, we introduce several interesting applications that exploit the RF-EHWC technology to provide smart healthcare services for animals, wirelessly charge the wearable devices, and implement 5G-assisted RF-EHWC

Development and Testing of Split-ring Antennas for Wearable Electro-textile UHF RFID Tags

Wireless body area network(WBAN) is developed from personal area network that helps different sensors to communicate while being worn on human body. The passive UHF (Ultra-high frequency) RFID (Radio frequency identification technology) is one of the fundamental technology used for tracking animals, people and objects. Currently, an emerging area of development is the use of wearable RFID tags in health care systems. The personal healthcare systems demand information about sensed or measured biological parameters to be reliable and rapidly sent over a wireless communication link for investigation purposes. Furthermore, the communication system must be absolutely flexible, low-power, maintenance-free and low-cost in order to be utilized on different parts of the patient’s body for continuous monitoring of physiological parameters such as blood pressure, body temperature, glucose level, and respiration system. Therefore, due to the extensive need for the implementation on flexible and conformal material, researchers have been working on textile based RFID tags. One of the hottest topics is the development of electro-textile based RFID tags for body area networks. In this thesis, to measure the performance of wearable split ring antennas on electro-textile material, different split ring antennas have been developed that are materialized with two different kinds of materials such as copper and electro-textile. The development of wearable antenna is quite challenging task due to antenna material properties, environmental issues and radiation absorbing nature of human body at higher frequencies. By considering these factors, 85% antenna-IC power transfer efficiency at 915MHz has been achieved in body-worn configuration. Furthermore, to analyze the near body performance of developed antenna, distance between antenna and the human body has been varied, for example 2 mm, 3mm, 5mm and air. Moreover, to measure the performance of antenna on clothes, EPDM (Ethylene-Propylene-Diene-Monomer) substrate of different thicknesses i.e 2mm and 5mm have been used. From the simulated and measured results, it has been noticed that copper based split ring UHF RFID tag shows excellent match between measured and simulated results in body-worn configuration. Furthermore, provides excellent tag performance at variable antenna-body separations down to two millimeters and also in the air. Interestingly, this is novel feature of wearable antennas based on a single conductor layer. On the other hand, it has been analyzed that electro-textile based split ring RFID tag shows some variation between simulated and measured on-body/off-body results

Ultra Low Energy Communication Protocol for Implantable Wireless Body Sensor Networks

Abstract Title: Ultra Low Energy Communication Protocol for Implantable Wireless Body Sensor Networks. Fariborz Fereydouni_Forouzandeh, Ph.D. Concordia University, 2010 Medical science will soon start to benefit from wireless communication and implantable sensor technologies being developed for use in the human body. Such technologies have a potential to revolutionize the health-care industry by providing real-time patient monitoring capabilities to the health-care professionals. In this regard, implantable wireless body sensor networks (IWBSNs) have recently emerged as an important and growing area of research. The implantable sensors are required to be reliable and very small so that the body does not reject them. They must stay functional in the human body for years, and most importantly, they must not be a source of discomfort to the potential patients. The life time of their embedded batteries could vary from a few days to a few weeks using current hardware and software technologies. In order to make such devices suitable for implantation an order of magnitude reduction in energy use is required. Our research is motivated by this goal. In this thesis, we identify and analyze the sources of energy use in typical devices meant for Implantation in a human body. Our detailed mathematical analysis and computer simulations clearly demonstrate that improving the efficiency of communication protocols is the only realistic way of achieving this goal. Unfortunately, none of the existing low range low energy wireless communication protocols can be used in IWBSNs because of the small energy resources available in the implanted sensor nodes. We propose a new energy aware communication protocol which efficiently encodes data in time domain. It ensures accurate transmission of information. The encoding scheme does this by sending only a single signal from the sensor node to the base station. The protocol is called the Time Based Coded Data protocol or TBCD in short. For proper operation of this protocol reliable synchronization is required. Our proposed synchronization algorithm is energy efficient and stable under worst case conditions as compared to existing algorithms. A sensor node using existing state of the art technology that can only last for a few weeks can be made to last for few years using our proposed communication protocol and the synchronization algorithm