Ultra-wideband Body Area Networks Research Articles

Liquid Crystal Polymer-Based Flexible Trap Ultra-Wideband Antenna Design

The wearable ultra-wideband antenna that is appropriate for body area networks is designed and implemented in this article. Stepped circular radiation patches, microstrip feeders, and trapezoidal floors make up the majority of the antenna. Good bending qualities have been attained by using liquid crystal polymer, a flexible material, as a dielectric substrate. An antenna measuring 30 mm × 35 mm × 0.1 mm was designed with two C-shaped slots etched on it to achieve notch function in the 3.20–4.10 GHz and 5.19–5.98 GHz frequency bands. Its working frequency range was 1.96–11.61 GHz, and its specific absorption rate for the human body was less than 2 W/kg. The test findings demonstrate that ultra-wideband body area network systems can be implemented using the antenna impedance and radiation characteristics.

Reliable communication in UWB body area networks using multiple hybrid relays

Body area networks (BANs) are wireless networks around the human body. Ultra-wideband (UWB) is one of the most preferred candidates for the physical layer of BAN. However, the attenuation due to human body tissues and the movement of body parts with respect to each other causes severe attenuation and limits the range of UWB. Hence, new and novel methods are required to improve communications in UWB BAN. The paper proposes, hybrid amplify forward and decode forward relays for communication in body area networks. Scenarios in the presence of multiple relays for both body surface and body surface to external models have been taken into consideration. The performance has been tested using IEEE 802.15 task group 6 designated channel models developed from real-time measurements. The findings from the analytical as well as simulation-based study indicate that hybrid relaying provides a versatile performance, and improves the reliability of the communication link by decreasing the bit error rate. The performance has been further validated by the transmission of medical magnetic resonance images. The results indicate that hybrid relaying has the best performance, and it can undoubtedly improve the reliability of the body area networks.

Multi-relay cooperative body surface communications in ultra-wideband body area networks

Ultra-wideband (UWB)-based body area networks (BAN) are envisioned to provide health care to patients on the move, and monitor patients’ health. Since UWB uses transmit power lower than 1mW, the link performance degrades due to absorption in body tissues and channel impairments. In BAN, multiple sensor nodes present between the transmitter and the receiver can act as relays to improve the link quality, thereby improving the energy efficiency and reliability.In this paper, we suggest a novel cooperative communications scenario for BAN and present a comparative bit error rate performance analysis of amplify forward and decode forward strategies using multiple relays. A power performance analysis, and validation of performance by transmitting electrocardiogram signals and magnetic resonance images, and recording the bit error rates, root mean square error and peak signal to noise ratio proves that proposed methods provide better performance compared to direct transmission.

Multiple narrowband interference mitigation using hybrid Hermite pulses for body surface to external communications in UWB body area networks

Wireless body area networks (BAN) are primarily being designed for the detection of diseases and tracking of patients on the move. Due to its low-power requirements, ultra-wideband (UWB) has become the most preferred candidate for the physical layer of BAN. However, UWB suffers from the interferences from existing wireless networks. Again, the interference mitigation techniques developed for UWB will not be feasible for BAN because of their complexity and resulting power consumption. In this paper, we have proposed a hybrid Hermite pulse for cancelling multiple narrowband interferences. A comparison of the proposed technique with existing techniques is presented based on the operations count that highlights the lower complexity of the proposed technique. The proposed technique is also compared to Gaussian pulse based hybrid pulse in the simulation section to prove its superiority. Mathematical and simulation results prove that besides being of lower complexity the technique can mitigate the interferences satisfactorily.

Characteristic of Ultra Wideband Body Area Network Channel

Characteristic of Ultra Wideband Body Area Network Channel

Hybrid Relaying in Ultra-wideband Body Area Networks

Body area networks (BAN) are a new variety of wireless sensor networks which are being developed to track patients' health. The 3.1---10.6 GHz ultra wideband band based BAN design has received huge...

Multiple Narrowband Interference Cancellation in High Data Rate UWB Body Area Networks using Hybrid Hermite Pulses

Body area networks (BAN) are being developed to serve the mankind, for detection of diseases and tracking of patients. And ultra wideband (UWB) has become the most preferred candidate for the physical layer of BAN. However, UWB BAN will suffer from the interferences from existing wireless networks. Though a number of mitigation techniques have been developed for UWB they will not be feasible for BAN because of their complexity and resulting power consumption. In this paper we propose hybrid Hermite pulse for cancelling multiple narrowband interferences. The technique is specially developed for UWB based BANs and has lower complexity compared to existing techniques. The proposed technique has been compared with its Gaussian counterpart and the performances have been studied through Monte-Carlo simulations in the BAN CM3 channel model. Further, ECG signal has been transmitted to validate the performance of the proposed technique.

Performance of amplify forward and decode forward cooperative strategies for body surface communications in UWB Body Area Networks

SummaryBody area networks (BAN) are being developed for telemonitoring of patients. Ultra wideband (UWB) is the most preferred choice for the physical layer of the BAN as it provides high data rate at low power consumption along with a simple transceiver structure. But because of high fading characteristics of the human body channel, the range of UWB will be limited, and a reliable communication cannot be guaranteed. In that case, cooperative communications may be applied to BAN for improving system performance and link quality.The paper proposes a novel approach by applying amplify and forward, and decode and forward cooperative relaying strategies with maximal ratio combining for BAN. The performance of single relay AF and DF relaying have been compared with direct transmission. Further, the efficacy of the proposed strategies has been validated by transmitting electrocardiogram signals and magnetic resonance imaging images. Simulations and validations have been carried out on Institute of Electrical and Electronics Engineers designated CM3 channel model for BAN designed from real time measurements data. A signal‐to‐noise ratio gain of at least 3 dB is clearly observed from simulation results. Thus, transmit power requirement can be minimized, which in turn improves the battery life of body sensor nodes. Copyright © 2015 John Wiley & Sons, Ltd.

Simplified human phantoms for narrowband and ultra-wideband body area network modelling

Purpose – The purpose of this paper is to compare the properties of simplified physical and corresponding numerical human body models (phantoms) and verify their applicability to path loss modeling in narrowband and ultra-wideband on-body wireless body area networks (WBANs). One of the models has been proposed by the authors. Design/methodology/approach – Two simplified numerical and two physical phantoms for body area network on-body channel computer simulation and field measurement results are presented and compared. Findings – Computer simulations and measurements which were carried out for the proposed simplified six-cylinder model with various antenna locations lead to the general conclusion that the proposed phantom can be successfully used for experimental investigation and testing of on-body WBANs both in ISM and UWB IEEE 802.15.6 frequency bands. Research limitations/implications – Usage of the proposed phantoms for the simulation/measurement of the specific absorption rate and for off-body channels are not within the scope of this paper. Practical implications – The proposed simplified phantom can be easily made with a low cost in other laboratories and be used both for research and development of WBAN technologies. The model is most suitable for wearable antenna radiation pattern simulation and measurement. Social implications – Presented results facilitate applications of WBANs in medicine and health monitoring. Originality/value – A new six-cylinder phantom has been proposed. The proposed simplified phantom can be easily made with a low cost in other laboratories and be used both for research and development of WBAN technologies.

Optimal Frame Length to Maximize Energy Efficiency in IEEE 802.15.6 UWB Body Area Networks

Energy efficiency is a major requirement in wireless body area networks (WBANs). In this letter, we optimize the length of the medium access control (MAC) frame body to maximize the energy efficiency in IEEE 802.15.6 ultra-wideband (UWB) WBANs. To achieve this, we derive the probability of packet detection as well as the probability of successful reception of the physical layer header and data payload for the two UWB physical layer modes i.e., the default mode and the high QoS mode. The analysis includes the impact of forward error correction and type II hybrid ARQ on the packet success rate. We further extend the existing model of energy efficiency by incorporating separate energy consumption costs for uplink and downlink channels as well as data transmission and reception. The correctness of the theoretical model is assessed and verified by means of system level simulations, and a closed form expression for optimal frame length is given for the default mode.

UWB body area network channel modeling: An analytical approach

The aim of this work is to develop an analytically-based approach for ultra wide band (UWB) body area network (BAN) channel modeling. In detail, the body will be modeled as multi-layered stratified cylinders of infinite length, and the Maxwell's equation will be solved for plane wave and line source excitations. Human-type tissues will be assumed in the multi-layered stratified cylindrical model. Validation of the procedure through measurement results has been provided.

An Improved Antenna Mounting for Ultra-Wideband On-Body Communications and Channel Characterization

The electromagnetic coupling of antennas with the human body is a well-known, but often neglected, problem in body area network (BAN) communications. The resulting distortion of the antenna's free-space characteristics may, in turn, demand more complex terminals to cope with the different conditions encountered as antennas are mounted on different parts of the body and/or varying separations from the skin. Therefore, in this paper, we propose a mounting method to provide a more stable response and to reduce the antenna's coupling to the body for ultra-wideband (UWB) BAN applications. The proposed mounting method is evaluated on two UWB BAN antennas, characterizing the antennas coupling with the body by analyzing variations in the antennas reflection coefficient between 4-9 GHz, when mounted at different distances from the skin and at different locations on the body. The modified mounting method was found to increase the correlation coefficient between the antenna's reflection coefficient when in free space and mounted using 5 mm of spacer, for the two antennas, from 0.22 and 0.13, to 0.66 and 0.90. The free-space characteristics of the modified antennas are also tested, showing a reduction of up to 4.7 dB of radiated power into the body.

Coexistence and interworking between UMTS and UWB: a performance evaluation of a UMTS/UWB interoperability platform

Ultra wideband (UWB) radio technology is nowadays one of the most promising technologies for medium-short range communications. It has a wide range of applications including high data rate systems and low data rate systems with location and tracking. The interoperation of UWB with Wide Area Networks (WAN) technologies is very interesting in order to extend the scope of UWB applications, but harmless coexistence between them must be assured. Extensive research is being focused to the development of efficient mitigation techniques and the collaboration between both radio services is an interesting solution when UWB is collocated in the same device with other radio technology. In this paper a UMTS/UWB interworking platform is presented, which allows remote monitoring of a UWB body area network for medical applications. The coexistence between UMTS and UWB is evaluated and cooperative mitigation techniques are proposed and implemented in the platform.

Hybrid ARQ Error-Controlling Scheme for Robust and Efficient Transmission of UWB Body Area Networks

This paper presents hybrid type-II automatic repeat request (H-ARQ) for wireless wearable body area networks (BANs) based on ultra wideband (UWB) technology. The proposed model is based on three schemes, namely, high rate optimized rate compatible punctured convolutional codes (HRO-RCPC), Reed Solomon (RS) invertible codes and their concatenation. Forward error correction (FEC) coding is combined with simple cyclic redundancy check (CRC) error detection. The performance is investigated for two channels: CM3 (on-body to on-body) and CM4 (on-body to a gateway) scenarios of the IEEE802.15.6 BAN channel models for BANs. It is shown that the improvement in performance in terms of throughput and error protection robustness is very significant. Thus, the proposed H-ARQ schemes can be employed and optimized to suit medical and non-medical applications. In particular we propose the use of FEC coding for non-medical applications as those require less stringent quality of service (QoS), while the incremental redundancy and ARQ configuration is utilized only for medical applications. Thus, higher QoS is guaranteed for medical application of BANs while allowing coexistence with non-medical applications.

Experimental Characterization of UWB On-Body Radio Channel in Indoor Environment Considering Different Antennas

An experimental investigation to characterize the transient and spectral behavior of the ultrawideband (UWB) on-body radio propagation channel for body-centric wireless communications is presented. The measurements were performed considering over thirty on-body links in the front of human body in the anechoic chamber, and in indoor environment. Two different pairs of planar antennas have been used, namely, CPW-fed planar inverted cone antennas (PICA), and miniaturized CPW-fed tapered slot antennas (TSA). A path loss model is extracted from measured data, and a statistical study is performed on the time delay parameters. The goodness of different statistical models in fitting the root mean square (RMS) delay has been evaluated. Results demonstrate that the TSA, due to its more directive radiation behavior is less affected from the reflections from body parts and surrounding environment. The antenna shows significant size reduction and improved time delay behavior, and hence is an ideal candidate for UWB body area networks (BAN).