Body Area Networks
World Health Organisation statistics show that millions of people suffer from obesity or chronic deceases and the changing demographics of an ageing population not only indicate that these are areas of current concern in healthcare, but that they will become increasingly more important. As a result of such factors, the remote patient monitoring (RPM) market is expected to grow at a compound growth rate of around 56% and is expected to exceed $8 billion by 2014. Other sources estimate that the chronically ill patients in Europe alone will rise to 100 million within the next decade. Part of the solution to such healthcare issues is increased patient monitoring and this requires new or improved sensors, new software applications and new forms of connectivity to support them. One of the new forms of connectivity will be provided by the development and deployment of Wireless Body Area Networks (WBAN).
Wireless Body Area Networks (WBAN) or Body Area Networks (BAN) is an emerging area of wireless communication. These networks interconnect implantable and/or body worn wireless devices which can be used for medical sensors, e.g. to monitor vital body signs, or for consumer applications, e.g fitness monitoring. Typically these networks are connected to external networks via gateway devices which are either body worn or mounted close to the body. WBAN devices have typical communications range of up to 5 metres, while the lifetime, processing and data throughput capabilities vary depending on the application.
Applications areas include medical devices, health monitoring, elderly monitoring, disability assistance and entertainment. The use of wireless technology to connect devices, sensors and actuators eliminates the need for obstructive cabling which enables the person to move freely and increasingly to be monitored in the home rather than hospital. The BAN devices are able to monitor the body signs unattended and will perform sophisticated decision making in a collaborative manner.
Key challenges to the design and implementation of WBANs is the diverse spectrum of device requirements for this range of applications. Data rates can span from a few bits per second to megabits per second, lifetime from a few days to 10-15 years and reliability can be low for non-critical consumer electronic applications to high for critical medical applications.
Implantable devices enforce additional challenges to the hard energy constraint. A battery powered implanted device ideally must have lifetime of 10-15 years, while supporting functionality including sensing, data processing and network management with a small form factor which prohibits the increase of battery reserves. Additionally, development of implanted devices deep inside the body or under the skin impose channel propagation challenges due to the extreme nature of the propagation medium (tissue).
