The Minimum Number of Adaptive Array Antenna Elements for Interference Suppression in Ubiquitous Communication Environments

This paper investigates the minimum number of antenna elements of an adaptive array antenna (AAA) required to suppress unnecessary radiation to a single location in an indoor ubiquitous communication environment. In the investigation the relationship between the number of antenna elements of an AAA and its digitally-created antenna null width is demonstrated using antenna directivity control technique that has been proposed by the authors. Also, the angular spread around a terminal to a single location in an indoor communication environment is demonstrated with propagation measurements. Based on the computer simulation results and the angular spread obtained by propagation measurements, the authors specify that at least 6 antenna elements are required to suppress radiation to a single location in an indoor communication environment up to -60 dB.