Modern aircraft systems are becoming more and more complex over time. This increasing complexity has led to an increased desire for the monitoring of the health and operation of such systems. While a strictly wired approach may be feasible when the total numbers of sensors is low, modern aircraft may utilize hundreds or even thousands of sensors which monitor the various systems in the aircraft. However, routing and maintaining physical wired connections with such a large number of sensors becomes impractical.
One solution utilized to support a growing number of sensors on an aircraft is the use of wireless sensors. Wireless sensors can be distributed at will throughout the aircraft, without the penalty of wiring each sensor back to a centralized data monitoring system. The use of wireless sensors in an aircraft allows the aircraft designer more freedom in monitoring the various systems onboard the aircraft.
The typical wireless sensors used on an aircraft are low power devices that operate at a short range for a number of reasons. One reason is that it is desirable that the RF transmissions generated by the wireless sensors do not interfere with the operation of the aircraft. Another reason is that the RF spectrum that is available for use by the wireless sensors is not unlimited. Rather, only a finite number of wireless channels may be available to support the data communication activities of some hundreds or thousands of wireless sensors. For example, wireless sensors that are based on the Institute of Electrical and Electronic Engineers (IEEE) 802.15.4 standard are limited to one channel in Europe in the 868.0-868.6 megahertz (MHz) band, thirty channels in North America in the 902-928 MHz band, and sixteen channels worldwide in the 2400-2483.5 MHz band.
Due to the increasing number of wireless sensors that are desired by aircraft designers, it is important to utilize the limited RF resources efficiently and to provide the wireless sensors a gateway into the data network of the aircraft.