Peter Chadwick, Zarlink Semiconductor

With an aging western world population, increasing life spans, and growing pressure on resources, the area of what is known as ‘eHealth’ is of rapidly growing importance. Much of the successful application of eHealth depends on the movement of data in a timely and secure manner for the health care professionals, health insurance provider, government authorities, etc. But an important part lies in areas such as patient monitoring (BSN, BAN), implanted devices telemetry, and telecontrol of external stimulating devices.

The application of conventional radio techniques can be limited by various constraints. These include equipment and antenna size, biocompatibility, biological limitations on RF exposure, body tissue attenuation, battery power availability (especially in implanted devices), communications latency, and reliability of both communication and equipment. Additionally, with the lack of dedicated spectrum, the safety involved with the RF link and the effects of interference add a further dimension to the challenges faced by the wireless medical systems designer. This paper considers some of the applications and the associated constraints, together with the existing spectrum regulatory and standardisation frameworks.