  In vivo wireless medical devices have the potential to play a vital role in
future healthcare technologies by improving the quality of human life. In order
to fully exploit the capabilities of such devices, it is necessary to
characterize and model the in vivo wireless communication channel. Utilization
of this model will have a significant role in improving the communication
performance of embedded medical devices in terms of power, reliability and
spectral efficiency. In this paper, the state of the art in this field is
presented to provide a comprehensive understanding of current models. Such
knowledge will be used to optimize the design and selection of various in vivo
wireless communication methods, operational frequencies, and antenna design.
Finally, open research areas are discussed for future studies.
