Same cell co-channel interference reduction using multiple spatially distributed adaptive array systems

In this paper, a method is proposed whereby the interference between multiple co-channel users can substantially be reduced, compared to conventional arrays located in the cell center. The proposed technique employs planar multi-angle user discrimination. This is achieved by means of a distributed antenna array system, consisting of three antenna sub-arrays whose centers are spaced far apart compared to the operating wavelength. The sub-arrays are located at the edges of a regular hexagonal cell. Although the proposed configuration can be used in both the up- and down-link, this paper deals with the up-link only. Utilizing the least mean squares technique, the steering vector is optimized for the complete array to yield the best signal to interference ratio for all the co-channel users in the same cell. The signal to interference performance of the proposed system is compared to conventional antenna array systems, located at the center of a cell. (C) 2001 Elsevier Science B.V. All rights reserved.