Experiments on Shadow Effects of Body and Effective Paths for UWB Transmission in BAN

Wireless technology is expected to be introduced into the medical care in recent year. Acquiring patient´s vital information by using BAN (body area network), which is a network very near from human body, is a promising application. A radio technique which is expected in this network area is UWB (Ultra Wideband). In BAN, obstruction of a person for the visibility of the transmitter and receiver occurs at a high probability. Therefore the discussion of the influence that human body gives UWB signal is a necessity. In this paper, the experiment that assumed the UWB communication in BAN is conducted. The wideband channel response is measured where the human body interrupts the visibility of the antennas, and the effects of wall and floor are investigated. It is confirmed that the influence with human body is large from these measurement results. However, the reflected waves from wall and floor become effective and reliable paths for UWB BAN because the influence from human body is less. BER performances with the effects of human body and wall and floor are acquired. By the existence of the reflected wave, BER performance is better and less transmitting power density will be required than the no reflector environment.