The performance enhancement of multibeam adaptive base-station antennas for cellular land mobile radio systems

Abstract

The problem of meeting the proliferating demands for mo- bile telephony within the confinements of the limited radio spectrum allocated to these services is addressed. A multiple beam adaptive base- station antenna is proposed as a major system component in an attempt to solve this problem. This novel approach is demonstrated here by em- ploying an antenna array capable of resolving the angular distribution of the mobile users as seen at the hase-station site, and then using this information to direct beams toward either lone mobiles, or groupings of mobiles, for both transmit and receive modes of operation. The en- ergy associated with each mobile is thus confined within the addressed volume, greatly reducing the amount of co-channel interference experi- enced from and by neighboring co-channel cells. In order to ascertain the benefits of such an antenna, a theoretical approach is adopted which models the conventional and proposed antenna systems in a typical mo- bile radio environment. For a given performance criterion, this indicates that a significant increase in the spectral efficiency, or capacity, of the network is obtainable with the proposed adaptive base-station antenna.