Outdoor-Indoor Wireless Sensor Communications in a modern Building Management System

Outdoor environmental monitoring will be used to enhance future BMS performance, from video surveillance applications and security (UWB wireless sensors), to monitors to respond to cold snaps, daylight monitor- ing, etc (typically using narrowband ISM sensors). However, the modern buildings also have a strong heat control requirement, realised using metal-coated insulation in the cavity or building cladding and also using metal oxide coating on the inner leaf of double glazed windows. The latter has excellent reflection properties (bi-directional) for electromagnetic wavelengths from Infra Red upwards, which has significant consequences for communications (reflecting typically more than 90%), but means shorter wavelength radiation (especially the visible spectrum), passes relatively well. This work presents measurements at frequencies relevant to ISM band and UWB wireless sensors and highlights the significant losses incurred in communicating to or from an external sensor. We were recently funded (TSR Strand 1) to carry out further work to examine means of improving wireless penetration into energy efficient buildings