Internet of things in health: Requirements, issues, and gaps

Background and objectives: The Internet of Things (IoT) paradigm has been extensively applied to several sectors in the last years, ranging from industry to smart cities. In the health domain, IoT makes possible new scenarios of healthcare delivery as well as collecting and processing health data in real time from sensors in order to make informed decisions. However, this domain is complex and presents several tech- nological challenges. Despite the extensive literature about this topic, the application of IoT in healthcare scarcely covers requirements of this sector. Methods: A literature review from January 2010 to February 2021 was performed resulting in 12,108 articles. After filtering by title, abstract, and content, 86 were eligible and examined according to three requirement themes: data lifecycle; trust, security, and privacy; and human-related issues. Results: The analysis of the reviewed literature shows that most approaches consider IoT application in healthcare merely as in any other domain (industry, smart cities…), with no regard of the specific requirements of this domain. Conclusions: Future effort s in this matter should be aligned with the specific requirements and needs of the health domain, so that exploiting the capabilities of the IoT paradigm may represent a meaningful step forward in the application of this technology in healthcare.Consejería de Conocimiento, Investigación y Universidad, Junta de Andalucía P18-TPJ - 307

An Impedance-Based Model for the Evaluation of IM3 in Nonlinear Amplifiers Showing Memory Effects

A simple model that captures nonlinear memory effects inwideband amplifiers is presented in this work. The model defines anequivalent hypothetical load impedance that explains asymmetries, inmagnitude and phase, in two-tone IM products, showing good corre-spondence with measurements. It helps to understand the intermodula-tion distortion dependence on modulation bandwidth.CICYT TEC2004-06451-C05-03/TC

Special Issue “Body Sensors Networks for E-Health Applications”

Body Sensor Networks (BSN) have emerged as a particularization of Wireless Sensor Networks (WSN) in the context of body monitoring environments, closely linked to healthcare applications. These networks are made up of smart biomedical sensors that allow the monitoring of physiological parameters and serve as the basis for e-Health applications. This Special Issue collects some of the latest developments in the field of BSN related to new developments in biomedical sensor technologies, the design and experimental characterization of on-body/in-body antennas and new communication protocols for BSN, including some review studies

Sensor Technologies to Manage the Physiological Traits of Chronic Pain: A Review

Non-oncologic chronic pain is a common high-morbidity impairment worldwide and acknowledged as a condition with significant incidence on quality of life. Pain intensity is largely perceived as a subjective experience, what makes challenging its objective measurement. However, the physiological traces of pain make possible its correlation with vital signs, such as heart rate variability, skin conductance, electromyogram, etc., or health performance metrics derived from daily activity monitoring or facial expressions, which can be acquired with diverse sensor technologies and multisensory approaches. As the assessment and management of pain are essential issues for a wide range of clinical disorders and treatments, this paper reviews different sensor-based approaches applied to the objective evaluation of non-oncological chronic pain. The space of available technologies and resources aimed at pain assessment represent a diversified set of alternatives that can be exploited to address the multidimensional nature of pain.Ministerio de Economía y Competitividad (Instituto de Salud Carlos III) PI15/00306Junta de Andalucía PIN-0394-2017Unión Europea "FRAIL

Amplifier Nonlinear Modeling with RF Pulses

This paper proposes a Volterra kernel identification procedure for wireless amplifiers with nonlinear memory. The technique is based on a reduced-order Volterra model for wideband amplifiers that is favorably compared with widely used memory polynomial model in terms of normalized mean square error. The identification method takes advantage of the particular model structure and is thoroughly derived with a proper selection of pulse-like waveforms of known amplitude as probing signals with special emphasis on the extraction of the fifth-order kernel. The main advantage of the method is that it allows exploring the dynamic range of the amplifier without rising the temperature in the device or altering the biasing point. For validation purposes, a commercial amplifier has been characterized and the extracted kernels have been used to predict the response under wideband code-division multiple-access-like signals. In addition to the simplicity of the deterministic approach used in this extraction procedure, the agreement of the predicted responses with measurements was highly satisfactory in all cases and permitted the capture of phenomena that are due to nonlinear memory effects.CICYT TEC2004-06451-C05-03Junta de Andalucía Grant P07-TIC-0264

Adaptation and application of the IEEE 2413-2019 standard security mechanisms to IoMT systems

Healthcare information systems are evolving from traditional centralised architectures towards highly-mobile distributed environments within the connected health context. The IoMT paradigm is at the forefront of this technological revolution underlying the development of communication infrastructures connecting smart medical devices, healthcare information systems and services. The IEEE 2413 standard, a promising general architectural framework for the design and implementation of IoT systems, has recently been announced. This standard proposes a general description for different types of domains, including healthcare, but it does not contain an extension developed for the IoMT systems domain. This paper presents a first approach to adapt the IEEE 2413 standard to the design of IoMT systems from a security perspective, considering the most relevant aspects of the standard for the construction of this type of systems. The application to an IoMT system for monitoring patients with chronic obstructive pulmonary disease is presented as a use case.Fundación Mutua MadrileñaSociedad Española de Diabete

Volterra Behavioral Model for Wideband RF Amplifiers

This paper proposes a behavioral modeling approach for the description of nonlinearities in wideband wireless communication circuits with memory. The model is formally derived exploiting the dependence on frequency of the amplifier nonlinear transfer functions and reduce the number of parameters in a general Volterra-based behavioral model. To validate the proposed approach, a commercial amplifier at 915 MHz, exhibiting nonlinear memory effects, has been widely characterized using different stimuli, including two tones, quadrature phase-shift keying wideband code division multiple access, and 16-quadrature amplitude modulation signals with rectangular and root-raised cosine conforming pulses. The theoretical results have been compared with experimental data demonstrating that the model performance is comparable to the well-established memory polynomial model. Calculated and measured baseband waveforms, signal constellation, spectral regrowth and adjacent channel power ratio are tightly coincident in all cases, emphasizing the relevance of the proposed modelCICYT TEC2004-06451-C05-0

Lessons Learned about the Design and Active Characterization of On-Body Antennas in the 2.4 GHz Frequency Band

This work addresses the design and experimental characterization of on-body antennas, which play an essential role within Body Sensor Networks. Four antenna designs were selected from a set of eighteen antenna choices and finally implemented for both passive and active measurements. The issues raised during the process of this work (requirements study, technology selection, development and optimization of antennas, impedance matching, unbalanced to balanced transformation, passive and active characterization, off-body and on-body configurations, etc.) were studied and solved, driving a methodology for the characterization of on-body antennas, including transceiver effects. Despite the influence of the body, the antennas showed appropriate results for an in-door environment. Another novelty is the proposal and validation of a phantom to emulate human experimentation. The differences between experimental and simulated results highlight a set of circumstances to be taken into account during the design process of an on-body antenna: more comprehensive simulation schemes to take into account the hardware effects and a custom design process that considers the application for which the device will be used, as well as the effects that can be caused by the human body.Ministerio de Economía y Competitividad (Instituto de Salud Carlos III) PI15/00306Junta de Andalucía PIN-0394-2017Unión Europea "FRAIL

Performance of a behavioral model with long-term memory effects

This paper presents a new behavioral model for power amplifiers that accomplishes the capture of nonlinear low-frequency memory effects with reduced complexity and superior precision. It has been extensively evaluated with a commercial amplifier using wideband code-division multiple-access (WCDMA)-like modulated data with symbol rates in the range of 2 ksym/s to 1 Msym/s, and it is shown that the first dynamic reduction of the proposed model is successfully compared with other highly efficient methods in terms of complexity and generalization capacity.CICYT TEC2011-23559Junta de Andalucía P11-TIC-786

A New Approach to Pruning Volterra Models for Power Amplifiers

The objective of this paper is to present an approach to behavioral modeling that can be applied to predict the nonlinear response of power amplifiers with memory. Starting with the discrete-time, complex-baseband full Volterra model, we define a novel methodology that retains only radial branches that can be implemented with one-dimensional finite impulse response filters. This model is subsequently simplified by selecting a subset of directions using an ad hoc procedure. Both models are evaluated in terms of accuracy in the time and frequency domains and complexity, and are compared with other models described in the literature. The evaluation is conducted using a low-voltage silicon RF driver amplifier and a 5-W PA, which are characterized at different levels with diverse modulation formats, including wideband code-division multiple-access (WCDMA) and orthogonal frequency-division multiplexed (OFDM) signals. In all cases, comparison of the measured and simulated responses confirms the effectiveness of the proposed approach.CICYT TEC2008-06259/TECJunta de Andalucía P07-TIC-0264