Beam diversity for indoor WLAN systems

Fading caused by multipath propagation and by shadowing is a significant problem for wireless local area networks (WLANs). The use of diversity can mitigate the effects of this fading. In this paper we report on the effect of using beam selection diversity for a 2.4 GHz WLAN system. Propagation measurements were made in a typical office environment using a planar antenna array capable of forming seven simultaneous 10-degree beams. The beam selection diversity receiver selected the best beam, either on a packet-by-packet basis or using a long-term average measurement. Measurement results show that the mean received signal strength can be significantly increased by use of beam selection diversity. We investigated both average and packet-by-packet beam selection diversity. Simulation results demonstrate that beam selection diversity performs well for a wide range of angle of arrival spreads.