Measurement of Channel Gain Characteristics of Human Body Communication Systems by using Impulse Signals

Human body communication (HBC) is a promising technology for realizing smart personal identification systems where users do not have to touch with IC cards. A severe problem of HBC is that an outsider in the vicinity of the system is often misidentified. A feasible solution to this problem is to classify signals sent from the user/outsider based on the HBC channel-gain feature G(f). To apply the classification scheme to real identification systems, G(f) must be acquired in a short time. A reasonable way to quickly acquire G(f) is to measure the impulse response of the HBC channel. We first demonstrated that G(f) can be correctly acquired by using the impulse signals. This result is an important step toward establishment of the smart identification systems.