Towards Implantable Body Sensor Networks - Performance of MICS Band Radio Communication in Animal Tissue

Reliable wireless communication inside the human body is crucial for the design of implantable body sensor networks. The tissues in human body are heterogeneous and have different conductivity and permittivity, which make the modeling of the wireless channel challenging. The design of upper layers of the network stack requires the physical layer characteristics including the channel model. Currently, there is no unique channel model available for implant communication inside body. Various measurement campaigns of channel characteristics are underway. The channel model characteristics depends on the hardware components used such as antenna and matching circuit as well as the operating frequency, which are not taken into account by the existing channel models for implant communication. Moreover, hardware losses and different tissue characteristics have not been taken into account in the link budget of the existing channel models. The approach used in this paper pays special attention to the losses introduced by hardware components of the implant itself and the physical medium. This paper presents characteristics of radio channel using animal tissue. A comparison is made between these measured characteristics and the existing channel characteristics provided by the IEEE 802.15.6 standard. The empirical measurements are used to validate the simulations of the IEEE 802.15.6 model.