iRFSim for BSNs -Imaging based subject-specific RF simulation environment for wearable and implantable wireless Body Sensor Networks (BSNs)

随着可穿戴和植入式医疗设备的日益复杂以及它们与无线传感器的集成，研究和商业组织正在寻求不断扩大的治疗和诊断应用范围。这些新的微型无线设备包括，例如，环境感知植入式起搏器和心脏除颤器，由患者按需操作的尿路无线控制阀门，以恢复膀胱控制，以及集成的药物输送治疗系统，例如用于糖尿病患者的快速作用胰岛素的系统。对于这些设备来说，用于询问植入物并与其通信的无线数据路径是整个系统设计中最重要的研究挑战之一，因为它具有巨大的功耗和人体内的复杂特征。虽然通过空中的无线通信已经得到了广泛的研究，但从植入的设备通过人体进行通信是一个新的研究领域。人体对于无线信号来说是一个令人不快的、往往是有害的环境。植入式设备的典型几何形状，如植入式心脏除颤器和起搏器、植入式葡萄糖传感器、内窥镜和药物输送胶囊设备，范围从毫米到厘米不等。无线植入物仅限于紧凑的天线，需要完全表征并有效地耦合到收发机。还有一个问题是植入式设备所需的低功耗，这两个因素高度相关。为了设计能量高效的体内通信方案，了解波在人体内的传播和衰减机制是很重要的，但到目前为止还没有系统的探索。对感应电磁场和在体内传播的准确建模是设计可穿戴和可植入的无线传感器的先决条件。在人体内模拟电磁场和电波传播的困难主要是由于器官的形态复杂及其组织特性的异质性，再加上动态变形和对象间的变化。关于无线电波如何在体内衰减以及与之相关的体表周围的场行为，到目前为止还知之甚少。在这种情况下，体内多路径反射的特征是不同的，体内无线电传播预计是特定于对象的，并受到器官变形和身体运动的影响。为了开发具有优化的无线数据路径、长电池寿命和有效控制场分布的植入型设备，对这些问题的透彻理解对于基站传感器网络的未来发展至关重要。该提案的目标是为可穿戴和植入型无线体感网络(BSN)创建一种新的基于成像的特定于对象的射频仿真环境。它汇集了来自伦敦帝国理工学院(ICL)和伦敦大学玛丽女王学院(QMUL)的一个多学科团队，他们拥有医学成像、BSN、电磁建模、天线和无线电传播方面的专业知识。

With increasing sophistication of wearable and implantable medical devices and their integration with wireless sensors, ever-expanding ranges of therapeutic and diagnostic applications are being pursued by the research and commercial organisations. These new miniaturised wireless devices include, for example, context aware implanted pacemakers and cardiac defibrillators, wirelessly controlled valves in the urinary tract operating on-demand by the patients for restoring bladder control, and integrated drug-delivering therapeutic systems such as those used for fast-acting insulin in diabetics. For these devices, the wireless data-path used to interrogate and communicate with the implants represents one of the most significant research challenges in overall system design due to its significant power consumption and complex characteristics within the human body. While wireless communication through the air has been extensively studied, communication from implanted devices through the human body is a new area of study. The human body is an uninviting and often hostile environment for a wireless signal. Typical geometries of implantable devices, such as implantable cardiac defibrillators and pacemakers, implantable glucose sensors, endoscopic and drug-delivering capsule devices, vary from mm to cm ranges. Wireless implants are restricted to a compact antenna that needs to be fully characterised and effectively coupled to the transceiver. There is also an issue of low power consumption required by implantable devices and these two factors are highly related. In order to design power efficient in-body communication schemes, understanding the mechanism of wave propagation and attenuation inside human body is important, but so far has not been explored systematically. Accurate modelling of induced electromagnetic fields and propagation in the body is a prerequisite to the design of wearable and implantable wireless sensors. The difficulty of simulating electromagnetic field and radio propagation within the human body is mainly due to the morphological complexity of organs and their heterogeneous tissue characteristics, coupled with dynamic deformation and inter-subject variations. In terms of how radiowave attenuates inside the body and the associated field behaviour around the body surface, there is so far limited knowledge. In this case, the characteristics of in vivo multiple path reflection is different and in vivo radio propagation is expected to be subject-specific and influenced by organ deformation and body movements. For developing implantable devices with optimised wireless data-path, long battery life, and effective control of field distribution, a thorough understanding of these issues is critical to the future advancement of BSNs.The objective of this proposal is to create a new imaging based subject-specific RF simulation environment for wearable and implantable wireless Body Sensor Networks (BSNs). It brings together a multi-disciplinary team from Imperial College London (ICL) and Queen Mary, University of London (QMUL) with expertise in medical imaging, BSN, electromagnetic modelling, antennas and radio propagation.