Ultra wideband (UWB) technology has potential for short-range wireless communications, particularly in the healthcare sector. Researchers from the Centre for Wireless Communications, University of Oulu, Finland, have carried out simulations of wireless body area networks (WBANs) that use UWB to investigate how such technology might be used in a real hospital environment.
The research, to be published in the International Journal of Ultra Wideband Communications and Systems, promises widespread applications particularly for the growing population of elderly patients in developed countries. The study describes the wireless transfer of measured information based on widely used applications.
Ville Niemelä, Matti Hämäläinen and Jari Iinatti have studied the performance of different UWB receivers using measurements from a real hospital environment with a transceiver system based on the 2007 IEEE 802.15.4a UWB standard. UWB, they explain, provides short-range communications, out of which the well-known Bluetooth wireless system is a good example of a technology already in use. The standard was originally targeted at low-complexity and low-cost devices operating in wireless personal area networks (WPANs) , which also makes it potentially suitable for WBANs. The team points out that a subsequent UWB standard, IEEE 802.15.6, which is targeted directly at WBANs, is now being finalised and is likely to be published later in 2012.
There are various technologies including Bluetooth, Zigbee, wireless-LAN and UWB that could be useful in a medical environment. Each has its advantages and disadvantages. The first three use “crowded” frequencies that overlap with countless consumer and other wirelessly connected devices. Bluetooth and WLAN also tend to be heavy power consumers, which makes them less appropriate for remote and mobile sensors that cannot be conveniently connected to mains power nor recharged frequently. UWB, on the other hand, uses less power and operates in a less crowded range of frequencies. However, it has challenges in converging world-wide spectrum definitions and the signal propagation challenges around the human body when being used in BAN applications.
The Oulu team thus focused on this wireless technology for WBAN studies. The researchers demonstrated good performance of UWB with the so-called all-rake implementation, a theoretical maximum when compared to the more realistic real implementations of S- and P-Rake receivers. UWB is appropriate for general hospital applications and is not detrimentally affected by the specifics of the environment.
One possible medical scenario would be to have small sensors attached to the body to measure different physiological parameters,” Niemelä explains. These parameters might be, for example, body temperature, respiration rate or electrocardiograph. From a single sensor, the information is transmitted to a WBAN access point, which might even be a cell phone. If not a cell phone, there is a room access point forwarding the information from WBAN access point to an electronic database accessed by the healthcare staff. The WBAN set-up could be established in various places, such as in a hospital room, at home or in an ambulance. The benefits of its implementation might be shorter and more efficient periods spent in hospital, lower overall healthcare costs and improved treatment procedures offering less work load for the healthcare staff, the team says.
“We have evaluated the hospital environment and its influence on the signal propagation as well as the impact of the human body,” explains Niemelä.”The 2007 standard for impulse radio UWB was the basis of our study. All the receiver structures studied can detect the standard defined signal model. The study also included some evaluation of the features of the standard, i.e., the channel coding efficacy.”
“IEEE 802.15.4a UWB receivers in medical applications” in Int. J. Ultra Wideband Communications and Systems, Vol. 2, 73-82