Physical Multi-Layer Phantoms for Intra-Body Communications

This paper presents approaches to creating tissue mimicking materials that can be used as phantoms for evaluating the performance of Body Area Networks (BAN). The main goal of the paper is to describe a methodology to create a repeatable experimental BAN platform that can be customized depending on the BAN scenario under test. Comparisons between different material compositions and percentages are shown, along with the resulting electrical properties of each mixture over the frequency range of interest for intra-body communications; 100 KHz to 100 MHz. Test results on a composite multi-layer sample are presented confirming the efficacy of the proposed methodology. To date, this is the first paper that provides guidance on how to decide on concentration levels of ingredients, depending on the exact frequency range of operation, and the desired matched electrical characteristics (conductivity vs. permittivity), to create multi-layer phantoms for intra-body communication applications

Multiple Antenna Techniques for Terahertz Nano-Bio Communication

Using higher frequency bands becomes an essential demand resulting from the explosive wireless traffic needs and the spectrum shortage of the currently used bands. This paper presents an overview on the terahertz technology and its application in the area of multi-input multi-output antenna system and in-vivo nano-communication. In addition, it presents a preliminary study on applying multiple input-single output (MISO) antenna technique to investigate the signal propagation and antenna diversity techniques inside the human skin tissues, which is represented by three layers: stratum corneum (SC), epidermis, and dermis layers, in the terahertz (THz) frequency range (0.8-1.2) THz. The spatial antenna diversity is investigated in this study to understand MISO system performance for two different in-vivo channels resulting from the signal propagation between two transmitting antennas, located at the dermis layer, and one receiving antenna, located at epidermis layer. Three techniques are investigated: selection combining (SC), equal-gain combing (EGC), and maximum-ratio combining (MRC). The initial study indicates that using multiple antenna technique with THz might be not useful for in-vivo nano-communication

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

Future of smart cardiovascular implants

Cardiovascular disease remains the leading cause of death in Western society. Recent technological advances have opened the opportunity of developing new and innovative smart stent devices that have advanced electrical properties that can improve diagnosis and even treatment of previously intractable conditions, such as central line access failure, atherosclerosis and reporting on vascular grafts for renal dialysis. Here we review the latest advances in the field of cardiovascular medical implants, providing a broad overview of the application of their use in the context of cardiovascular disease rather than an in-depth analysis of the current state of the art. We cover their powering, communication and the challenges faced in their fabrication. We focus specifically on those devices required to maintain vascular access such as ones used to treat arterial disease, a major source of heart attacks and strokes. We look forward to advances in these technologies in the future and their implementation to improve the human condition

Near-field baseband communication system for use in biomedical implants

This thesis introduces the reader to the near-field baseband pulse radio communication for biomedical implants. It details the design and implementation of the complete communication system with a particular emphasis on the antenna structure and waveform coding that is compatible with this particular technology. The wireless communication system has great employability in small pill-sized biomedical diagnostic devices offering the advantages of low power consumption and easy integration with SoC and lab-in-a-pill technologies. The greatest challenge was the choice of antenna that had to be made to effectively transmit the pulses. A systematic approach has been carried out in arriving at the most suitable antenna for efficient emanation of pulses and the fields around it are analysed electromagnetically using a commercially available software. A magnetic antenna can be used to transmit the information from inside a human body to the outside world. The performance of the above antenna was evaluated in a salt solution of different concentrations which is similar to a highly conductive lossy medium like a human body. Near-field baseband pulse transmission is a waveform transmission scheme wherein the pulse shape is crucial for decoding information at the receiver. This demands a new approach to the antenna design, both at the transmitter and the receiver. The antenna had to be analysed in the time-domain to know its effects on the pulse and an expression for the antenna bandwidth has been proposed in this thesis. The receiving antenna should be able to detect very short pulses and while doing so has to also maintain the pulse shape with minimal distortion. Different loading congurations were explored to determine the most feasible one for receiving very short pulses. Return-to-zero (RZ), Non-return-zero (NRZ) and Manchester coded pulse waveforms were tested for their compatibility and performance with the near-field baseband pulse radio communication. It was concluded that Manchester coded waveform are perfectly suited for this particular near-field communication technology. Pulse interval modulation was also investigated and the findings suggested that it was easier to implement and had a high throughput rate too. A simple receiver algorithm has been suggested and practically tested on a digital signal processor. There is further scope for research to develop complex signal processing algorithms at the receiver

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

Analytical modelling of the effect of noise on the terahertz in-vivo communication channel for body-centric nano-networks

The paper presents an analytical model of the terahertz (THz) communication channel (0.1 - 10 THz) for in-vivo nano-networks by considering the effect of noise on link quality and information rate. The molecular absorption noise model for in-vivo nano-networks is developed based on the physical mechanisms of the noise present in the medium, which takes into account both the radiation of the medium and the molecular absorption from the transmitted signal. The signal-to-noise ratio (SNR) of the communication channel is investigated for different power allocation schemes and the maximum achievable information rate is studied to explore the potential of THz communication inside the human body. The obtained results show that the information rate is inversely proportional to the transmission distance. Based on the studies on channel performance, it can be concluded that the achievable transmission distance of in-vivo THz nano-networks should be restrained to approximately 2 mm maximum, while the operation band of in-vivo THz nano-networks should be limited to the lower band of the THz band. This motivates the utilisation of hierarchical/cooperative networking concepts and hybrid communication techniques using molecular and electromagnetic methods for future body-centric nano-networks