Cellular system having frequency plan and cell layout with reduced co-channel interference

Claim 1

A cellular radio-telephone system comprising: a first plurality of cells located adjacent to each other within a predetermined land area; the cells each commonly having a second plurality of sectors; the cells being grouped into clusters of N adjoining cells where N equals at least 2; each cell cluster having a set of assigned system frequencies; each cell within each cell cluster having a subset of frequencies from the frequency set so that N groups of co-channel cells exist with each co-channel cell group including one cell from each cluster having channel frequencies corresponding to those for its co-channel cell group; each sector within each cell having channels corresponding to a sub-subset of frequencies from the associated frequency subset; respective base station antennas located in the respective sectors of the respective cells; each of the cell sectors having a third plurality of subscriber station directional antennas disposed at predetermined locations within the sector for communication linkage with the associated base station antenna; the cells being disposed substantially in rows and columns and further being formed to provide a predetermined relative orientation pattern for co-channel cell sectors; co-channel cells forming a first cell tier around a preselected center co-channel cell with a common direction operative as a reference orientation direction for co-channel sectors therein; co-channel sectors in successive co-channel cells about the first tier being successively oriented in alternating first and second directions; and the alternating directions being a first direction corresponding to at least one sector rotation from the reference direction in the counter-clockwise direction and a second direction corresponding to at least one sector rotation from the reference direction in the clockwise direction.