Comparison of Distributed and Co-located Antenna Diversity Schemes for the Coverage Improvement of VoWLAN Systems

This paper concerns the coverage range of a high quality voice over wireless local area network (VoWLAN) system based on the IEEE 802.11a standard. Techniques for enhancing the coverage range of each access point (AP) using co-located and distributed antenna diversity schemes are proposed and it is shown that the number of required APs and therefore the infrastructure cost may thus be reduced. Comparisons are made between the coverage range of the 802.11a and that of DECT (digital enhanced cordless telecommunication), and simulations and channel measurements devised for predicting the effect of diversity techniques on the range of APs are described. The results of two different measurement campaigns are presented, one with co-located antennas and the other with locally distributed antennas. The coverage enhancement gained within these scenarios by employing diversity techniques is thus deduced