2,728 research outputs found
Improved reception of in-body signals by means of a wearable multi-antenna system
High data-rate wireless communication for in-body human implants is mainly performed in the 402-405 MHz Medical Implant Communication System band and the 2.45 GHz Industrial, Scientific and Medical band. The latter band offers larger bandwidth, enabling high-resolution live video transmission. Although in-body signal attenuation is larger, at least 29 dB more power may be transmitted in this band and the antenna efficiency for compact antennas at 2.45 GHz is also up to 10 times higher. Moreover, at the receive side, one can exploit the large surface provided by a garment by deploying multiple compact highly efficient wearable antennas, capturing the signals transmitted by the implant directly at the body surface, yielding stronger signals and reducing interference. In this paper, we implement a reliable 3.5 Mbps wearable textile multi-antenna system suitable for integration into a jacket worn by a patient, and evaluate its potential to improve the In-to-Out Body wireless link reliability by means of spatial receive diversity in a standardized measurement setup. We derive the optimal distribution and the minimum number of on-body antennas required to ensure signal levels that are large enough for real-time wireless endoscopy-capsule applications, at varying positions and orientations of the implant in the human body
Performance of ultrawideband wireless tags for on-body radio channel characterisation
Experimental characterisation of on-body radio channel for ultrawideband (UWB) wireless active tags is reported in this paper. The aim of this study is to investigate the performance of the commercially available wireless tags on the UWB on-body radio channel characterisation. Measurement campaigns are performed in the chamber and in an indoor environment. Statistical path loss parameters of nine different on-body radio channels for static and dynamic cases are shown and analyzed. Results demonstrated that lognormal distribution provides the best fits for on-body propagation channels path loss model. The path loss was modeled as a function of distance for 34 different receiver locations for propagation along the front part of the body. A reduction of 11.46% path loss exponent is noticed in case of indoor environment as compared to anechoic chamber. In addition, path loss exponent is also extracted for different body parts (trunk, arms, and legs). Second-order channel parameters as fade probability (FP), level crossing rate (LCR), and average fade duration (AFD) are also investigated
A comprehensive survey of wireless body area networks on PHY, MAC, and network layers solutions
Recent advances in microelectronics and integrated circuits, system-on-chip design, wireless communication and intelligent low-power sensors have allowed the realization of a Wireless Body Area Network (WBAN). A WBAN is a collection of low-power, miniaturized, invasive/non-invasive lightweight wireless sensor nodes that monitor the human body functions and the surrounding environment. In addition, it supports a number of innovative and interesting applications such as ubiquitous healthcare, entertainment, interactive gaming, and military applications. In this paper, the fundamental mechanisms of WBAN including architecture and topology, wireless implant communication, low-power Medium Access Control (MAC) and routing protocols are reviewed. A comprehensive study of the proposed technologies for WBAN at Physical (PHY), MAC, and Network layers is presented and many useful solutions are discussed for each layer. Finally, numerous WBAN applications are highlighted
Ultrawideband Technology for Medical In-Body Sensor Networks: An Overview of the Human Body as a Propagation Medium, Phantoms, and Approaches for Propagation Analysis
[EN] An in-body sensor network is that in which at least one of the sensors is located inside the human body. Such wireless in-body sensors are used mainly in medical applications, collecting and monitoring important parameters for health and disease treatment. IEEE Standard 802.15.6-2012 for wireless body area networks (WBANs) considers in-body communications in the Medical Implant Communications Service (MICS) band. Nevertheless, high-data-rate communications are not feasible at the MICS band because of its narrow occupied bandwidth. In this framework, ultrawideband (UWB) systems have emerged as a potential solution for in-body highdata-rate communications because of their miniaturization capabilities and low power consumption.This work was supported by the Programa de Ayudas de Investigación y Desarrollo (PAID-01-16) at the Universitat Politècnica de València, Spain; by the Ministerio de Economía y Competitividad, Spain (TEC2014-60258-C2-1-R); and by the European FEDER funds. It was also funded by the European Union’s H2020:MSCA:ITN program for the Wireless In-Body Environ-ment Communication–WiBEC project under grant 675353.Garcia-Pardo, C.; Andreu-Estellés, C.; Fornés Leal, A.; Castelló-Palacios, S.; Pérez-Simbor, S.; Barbi, M.; Vallés Lluch, A.... (2018). Ultrawideband Technology for Medical In-Body Sensor Networks: An Overview of the Human Body as a Propagation Medium, Phantoms, and Approaches for Propagation Analysis. IEEE Antennas and Propagation Magazine. 60(3):19-33. https://doi.org/10.1109/MAP.2018.2818458S193360
Antenna and radio channel characterisation for low‐power personal and body area networks
PhDThe continuous miniaturisation of sensors, as well as the progression in wearable electronics,
embedded software, digital signal processing and biomedical technologies, have led to new usercentric
networks, where devices can be carried in the user’s pockets, attached to the user’s body.
Body-centric wireless communications (BCWCs) is a central point in the development of fourth
generation mobile communications. Body-centric wireless networks take their place within the
personal area networks, body area networks and sensor networks which are all emerging
technologies that have a wide range of applications (such as, healthcare, entertainment,
surveillance, emergency, sports and military). The major difference between BCWC and
conventional wireless systems is the radio channels over which the communication takes place.
The human body is a hostile environment from a radio propagation perspective and it is therefore
important to understand and characterise the effects of the human body on the antenna elements,
the radio channel parameters and, hence, system performance. This thesis focuses on the study of
body-worn antennas and on-body radio propagation channels.
The performance parameters of five different narrowband (2.45 GHz) and four UWB (3.1-
10.6 GHz) body-worn antennas in the presence of human body are investigated and compared.
This was performed through a combination of numerical simulations and measurement
campaigns. Parametric studies and statistical analysis, addressing the human body effects on the
performance parameters of different types of narrowband and UWB antennas have been
presented. The aim of this study is to understand the human body effects on the antenna
parameters and specify the suitable antenna in BCWCs at both 2.45 GHz and UWB frequencies.
Extensive experimental investigations are carried out to study the effects of various antenna
types on the on-body radio propagation channels as well. Results and analysis emphasize the best
body-worn antenna for reliable and power-efficient on-body communications. Based on the
results and analysis, a novel dual-band and dual-mode antenna is proposed for power-efficient
and reliable on-body and off-body communications. The on-body performance of the DBDM
antenna at 2.45 GHz is compared with other five narrowband antennas. Based on the results and
analysis of six narrowband and four UWB antennas, antenna specifications and design guidelines
are provided that will help in selecting the best body-worn antenna for both narrowband and
UWB systems to be applied in body-centric wireless networks (BCWNs). A comparison between
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the narrowband and UWB antenna parameters are also provided. At the end of the thesis, the
subject-specificity of the on-body radio propagation channel at 2.45 GHz and 3-10 GHz was
experimentally investigated by considering eight real human test subjects of different shapes,
heights and sizes. The subject-specificity of the on-body radio propagation channels was
compared between the narrowband and UWB systems as well
A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles
In recent years, there has been a dramatic increase in the use of unmanned
aerial vehicles (UAVs), particularly for small UAVs, due to their affordable
prices, ease of availability, and ease of operability. Existing and future
applications of UAVs include remote surveillance and monitoring, relief
operations, package delivery, and communication backhaul infrastructure.
Additionally, UAVs are envisioned as an important component of 5G wireless
technology and beyond. The unique application scenarios for UAVs necessitate
accurate air-to-ground (AG) propagation channel models for designing and
evaluating UAV communication links for control/non-payload as well as payload
data transmissions. These AG propagation models have not been investigated in
detail when compared to terrestrial propagation models. In this paper, a
comprehensive survey is provided on available AG channel measurement campaigns,
large and small scale fading channel models, their limitations, and future
research directions for UAV communication scenarios
Joint optimal relay location and power allocation for ultra-wideband-based wireless body area networks
© 2015, Ding et al.; licensee Springer. In this paper, we study the joint optimal relay location and power allocation problem for single-relay-assisted ultra-wideband (UWB)-based wireless body area networks (WBANs). Specifically, to optimize spectral efficiency (SE) for single-relay cooperative communication in UWB-based WBANs, we seek the relay with the optimal location together with the corresponding optimal power allocation. With proposed relay-location-based network models, the SE maximization problems are mathematically formulated by considering three practical scenarios, namely, along-torso scenario, around-torso scenario, and in-body scenario. Taking into account realistic power considerations for each scenario, the optimal relay location and power allocation are jointly derived and analyzed. Numerical results show the necessity of utilization of relay node for the spectral and energy-efficient transmission in UWB-based WBANs and demonstrate the effectiveness of the proposed scheme in particular for the around-torso and in-body scenarios. With the joint optimal relay location and power allocation, the proposed scheme is able to prolong the network lifetime and extend the transmission range in WBANs significantly compared to direct transmission
Modelling and characterisation of antennas and propagation for body-centric wireless communication
PhDBody-Centric Wireless Communication (BCWC) is a central point in the development
of fourth generation mobile communications. The continuous miniaturisation of sensors,
in addition to the advancement in wearable electronics, embedded software, digital
signal processing and biomedical technologies, have led to a new concept of usercentric
networks, where devices can be carried in the user’s pockets, attached to the
user’s body or even implanted.
Body-centric wireless networks take their place within the personal area networks,
body area networks and body sensor networks which are all emerging technologies
that have a broad range of applications such as healthcare and personal entertainment.
The major difference between BCWC and conventional wireless systems is the
radio channel over which the communication takes place. The human body is a hostile
environment from radio propagation perspective and it is therefore important to understand
and characterise the effect of the human body on the antenna elements, the
radio channel parameters and hence the system performance. This is presented and
highlighted in the thesis through a combination of experimental and electromagnetic
numerical investigations, with a particular emphasis to the numerical analysis based
on the finite-difference time-domain technique.
The presented research work encapsulates the characteristics of the narrowband
(2.4 GHz) and ultra wide-band (3-10 GHz) on-body radio channels with respect to
different digital phantoms, body postures, and antenna types hence highlighting the
effect of subject-specific modelling, static and dynamic environments and antenna performance
on the overall body-centric network. The investigations covered extend further
to include in-body communications where the radio channel for telemetry with
medical implants is also analysed by considering the effect of different digital phantoms
on the radio channel characteristics. The study supports the significance of developing
powerful and reliable numerical modelling to be used in conjunction with measurement campaigns for a comprehensive understanding of the radio channel in
body-centric wireless communication. It also emphasises the importance of considering
subject-specific electromagnetic modelling to provide a reliable prediction of the
network performance
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