# Anatomical Region-Specific In Vivo Wireless Communication Channel Characterization

## TL;DR

This study characterizes in vivo wireless communication channels in the male torso at 915 MHz and 2.4 GHz, revealing region-specific path loss behaviors and multipath effects crucial for healthcare device design.

## Contribution

It provides the first comprehensive anatomical region-specific in vivo wireless channel model based on numerical and experimental data at two frequencies.

## Key findings

- Mean path loss decays linearly inside the body.
- Power decay rate is approximately twice at 2.4 GHz compared to 915 MHz.
- Shadowing variance increases with deeper antenna placement.

## Abstract

In vivo wireless body area networks (WBANs) and their associated technologies are shaping the future of healthcare by providing continuous health monitoring and noninvasive surgical capabilities, in addition to remote diagnostic and treatment of diseases. To fully exploit the potential of such devices, it is necessary to characterize the communication channel which will help to build reliable and high-performance communication systems. This paper presents an in vivo wireless communication channel characterization for male torso both numerically and experimentally (on a human cadaver) considering various organs at 915 MHz and 2.4 GHz. A statistical path loss (PL) model is introduced, and the anatomical region-specific parameters are provided. It is found that the mean PL in dB scale exhibits a linear decaying characteristic rather than an exponential decaying profile inside the body, and the power decay rate is approximately twice at 2.4 GHz as compared to 915 MHz. Moreover, the variance of shadowing increases significantly as the in vivo antenna is placed deeper inside the body since the main scatterers are present in the vicinity of the antenna. Multipath propagation characteristics are also investigated to facilitate proper waveform designs in the future wireless healthcare systems, and a root-mean-square (RMS) delay spread of 2.76 ns is observed at 5 cm depth. Results show that the in vivo channel exhibit different characteristics than the classical communication channels, and location dependency is very critical for accurate, reliable, and energy-efficient link budget calculations.