Delay spread issues for a DECT-based wireless local loop

Recent publications have indicated that the effects of propagation delay spread may not be as damaging as first feared when using the Digital European Cordless Telecommunications (DECT) standard in a wireless local loop (WLL) application. It has been suggested that the use of directional antennas in the WLL application is responsible for the surprisingly good performance exhibited in trials conducted using DECT based equipment. This paper proposes a two-path propagation model in two dimensions to theoretically examine the protection offered against excessive delay spread by the use of directional antennas. Results indicate that a range of 1 km, the use of a directional antenna at a multipoint network end can give protection from single reflectors out to a maximum distance of 350 m.