A decade ago, most of medical devices were implanted using wires to communicate with
circuitry outside the body. However wires often create surgical complications, including
breakage, infection and electrical noise. One of the alternatives is to establish wireless
communication using RF telemetry with implantable devices. Over the past couple of
decades, the radio Frequency (RF) technologies have evolved to such extend that it has
overcome the challenges encountered for implantable devices. The fundamental challenge is
the reduction of power and signal integrity for propagation of RF field due to EM absorption
and impedance boundaries of biological tissues in human body.
Additional challenge includes miniaturization and establishment of reliable communication
link with external world for daily monitoring basis especially when device is surrounded
other RF devices in places such as ICU (Intensive Care Unit). The traditional implants
used inductive links for communication which has limitations such as short range, physical
contact with subject, low frequency and convenient for home monitoring thereby, need for
higher data rates with longer range of communications were required.
To overcome above challenges a new Communication service MICS having frequency range
between 402-405 MHz was introduced by FCC in 1999.
This communication service is ultra Low power consumption, unlicensed mobile radio service
for transmitting data for diagnostic and real time monitoring purposes. As mentioned in
figure 4.1 Comparison of wired communication with RF using this communication service
it is now possible to upload the patient events into IMD and then transmit to base station
for analysis. With longer range it is now feasible for elderly people to monitor real time
data of IMD in-house with ease.
This document elaborates the state of art technique used to optimize the functionality of
base station using customized FPGA.