Interference Investigation of Wireless ISM Band Devices in Rescue Helicopters

The increasing wireless device density and data rate in ISM bands used by, e.g., public institutions, industrial facilities and private households, have lead to substantial interference between wireless transmissions. The most famous representative standards using the ISM band are IEEE 802.11 (WLAN) and IEEE 802.15 (Bluetooth, ZigBee, 6LoWPAN). Most of these standards are working in the 2.4 GHz ISM band resulting in mutual interference and causing significant performance degradations. This is a severe problem, especially in the area of aviation and medical surveillance, where reliability is one of the key requirements. This paper provides detailed studies on the interaction of these radio standards when used for connecting medical and aviation devices in rescue helicopters. All investigations focus on the mutual influence of the radio standards IEEE 802.11 (WLAN) and IEEE 802.15 (Bluetooth and 6LoWPAN). Due to the cumbersome approval procedures, medical technology manufacturers have not been able to establish a uniform standard for wireless communications among medical devices. The 6LoWPAN standard operates in the sub-1 GHz band and this paper shows that it is a compelling candidate for such a medical device communications standard.