Implanted Cardiac Pacemaker Mathematical Modeling and Research based on the Volume Conduction

The research of the communication between implanted Cardiac Pacemaker and external devices is a focus. In this paper, a data communications model based Volume Conduction is creatively presented, in this way the human body conductive ability will been utilized to transmit current, which is more effective and decrease for harm of the human body than the other ways, such as: RF, Optical Transcutaneous, etc. As the frequency increases the KHz level, the effect of background biological noise is considered negligible, the channel is thus modeled as AWGN channel in these frequencies. From Shannon information theory, in two-dimensional modulation, the volume conduction channel capacity formula was derived, further derivation: with extremely low SNR using in the two-level modulation can be very effective use of channel capacity, with high SNR a multi-level modulation is used in order to make full use of the channel capacity. Matlab software is used to the channel simulation, the input and output signal waveforms and eye diagram comparison, the curves of the BER and SNR.