Characteristics of the indoor wireless propagation environment at microwave and millimetre frequencies

Multimedia wireless networks are addressed at the in-building network market where they will ultimately offer a flexible and mobile alternative to wired LANs. The primary application of the technology is in the wireless communication of voice, data, and video signals. The potential market for indoor wireless LANs is considerable for both the commercial and domestic sectors. The choice of an appropriate transmission frequency for indoor wireless networks is an important one. The NII/SUPERNET/HIPERLAN band at 5 GHz is a strong contender as are those frequencies around 60 GHz. Future indoor wireless networks are expected to have data rates in excess of 100 Mbits/s in order to be compatible with future wired networks. A pivotal element in the design of future wireless LANs is knowledge of the propagation environment in which such systems are expected to be used. The indoor propagation channel is a complex one and it is dependent on the age, structure, and function of the building, the layout and occupancy of rooms, the presence of exterior and internal walls and windows, and the construction materials used. The paper investigates the indoor electromagnetic propagation environment at microwave and millimetre frequencies. This in turn requires examination of the mechanisms of electromagnetic wave propagation and the effects of the electromagnetic properties of building materials at these frequencies. Ultimately this study compares microwave and millimetre frequencies in terms of their respective suitability and feasibility for broadband indoor wireless communications