Hiroshi Hosaka

Development and performance analysis of an intra-body communication device

Personal area networks would benefit from a wireless communication system in which a variety of information could be exchanged through wearable electronic devices and sensors. Intra-body communication using the human body as the transmission medium enables wireless communication without transmitting radio waves through the air. A human arm phantom is designed and used to reduce uncertainty in experiments with the human body. The phantom exhibits transmission characteristics similar to those of the human body at frequencies between 1 MHz and 10 MHz. A 10.7 MHz frequency modulation (FM) intra-body transmitter and receiver are developed which allow transmission of analog sine waves even in the presence of external noise. Digital data transmission at 9600 bps was also achieved using newly fabricated 10.7 MHz frequency shift keying (FSK) transmitter and receiver devices. The carrier frequency of 10.7 MHz, which is the intermediate frequency in FM radio receivers, means that a wide selection of commercial radio frequency (RF) devices is available.

Bluetooth Indoor Positioning and Ambient Information System

Our system utilizes signal strength of Bluetooth wireless connection for indoor positioning. The position of a user carrying an information device equipped with Bluetooth, e.g. a mobile phone, will be estimated from signal strengths measured by base stations, e.g. desktop PCs in the rooms. One of these base stations will serve as a position server that collects signal strength measurements and calculates the user’s position. Using the indoor position as context information, we created a guidance system on our campus which gives relevant information according to the position and to the user’s goal or task.