Accuracy of localization system inside human body using a fast FDTD simulation technique

In this paper we analyze the accuracy of narrowband and wideband localization techniques inside the homogeneous human tissues using a fast finite difference time domain (FDTD) technique. In the narrowband localization, the phase of the received carrier signal is used for ranging measurements, whereas for the wideband transmission, the time of arrival (TOA) of the received signal is used. For fast computations, we introduce a new perspective to FDTD simulations of radio propagation by considering each simulation set for a given location of antennas as a Linear Time Invariant (LTI) discrete-time system. This way a set of simulations for a variety of transmitted waveforms can be reduced to only one simulation to determine the impulse response of the simulated channel between the two antennas and the convolution of the set of waveforms with this impulse response. A typical simulation using FDTD takes several minutes to a few hours and each convolution takes only a few seconds, resulting in a huge reduction in computational time.