Channel Models for Medical Implant Communication

Abstract

Information regarding the propagation media is typically gathered by conducting physical experiments, measuring and processing the corresponding data to obtain channel characteristics. When this propagation media is human body, for example in case of medical implants, then this approach might not be practical. In this paper, an immersive visualization environment is presented, which is used as a scientific instrument that gives us the ability to observe RF propagation from medical implants inside a human body. This virtual environment allows for more natural interaction between experts with different backgrounds, such as engineering and medical sciences. Here, we show how this platform has been used to determine channel models for medical implant communication systems.

Anatomical Region-Specific In Vivo Wireless Communication Channel Characterization

“…Also, the shadowing term (S) depends on the different body materials (e.g., bone, muscle, fat, etc.) and the antenna gain in different directions [15]. The proposed in vivo PL model is valid for 10 ≤ d ≤ 100 mm and the communication channel between an in vivo medical device, and a far external node could be considered as a combination of two concatenated channels: "in-body to on-body" and "classical indoor channel", if there are no surrounding objects around the body [25].…”

“…It is also known that EM wave propagation inside the human body is strongly related to the location of the antenna [8], [13] and hence, the in vivo channel should be investigated for a specific anatomical part. For example, the gastrointestinal tract has been studied for wireless capsule endoscopy applications [14], while the heart area has been investigated for implantable cardioverter defibrillators and pacemakers [15]. Although many in vivo path loss (PL) formulas were reported in the literature [4]- [7], [15]- [17], they do not provide location specific PL model parameters to carry out accurate link budget calculations.…”

“…For example, the gastrointestinal tract has been studied for wireless capsule endoscopy applications [14], while the heart area has been investigated for implantable cardioverter defibrillators and pacemakers [15]. Although many in vivo path loss (PL) formulas were reported in the literature [4]- [7], [15]- [17], they do not provide location specific PL model parameters to carry out accurate link budget calculations. Moreover, detailed human body models are crucial in order to investigate the in vivo wireless communication channel.…”

In Vivo Communications: Steps Toward the Next Generation of Implantable Devices

“…Figure 5 shows several investigated anatomical regions for various in vivo WBAN applications. For example, the heart area has been studied for implantable cardioverter defibrillator and pacemakers, while the gastrointestinal tract (GI) including esophagus, stomach and intestine has been Brain: [29], [38] Right Neck & Shoulder: [28] Clavicle: [16] Esophagus: [6] Left pectoral muscle: [28] Heart: [27], Stomach: [6], [27] , [28], [30] Arm: [16], [28] Intestine: [6], [39] Bladder: [27], Hand: [16] Leg: [28] investigated for WCE applications. The bladder region is studied for wirelessly controlled valves in the urinary tract and the brain is investigated for neural implants [29], [38].…”

“…bone, muscle, fat, etc.) and the antenna gain in different directions [28]. Figure 6 shows the scatter plot of path loss vs depth on a human male torso in a simulation environment [42].…”