摘要 |
<p>A method of assigning frequencies in a cellular telephone system in which a first group of the available frequencies is assigned to a first cell, and then distinct groups are assigned to adjacent cells, leaving at least one and preferably two distinct group of frequencies free for later re-use. The re-use groups of frequencies are assigned to cells that are non-adjacent to the first cell and equilaterally distributed about it. This method of assigning frequencies is applied to each cell in the system. For a first stage of cell splitting, frequencies are assigned from at least one non-adjacent cell (using the frequency re-use groups) to at least one part of the cell being split, while maintaining coverage of the cell from the same cell site. An example is given based on 9 cells with sites arranged for end radiation of 3 cells from one site, thus reducing the number of cell sites. At each site the 3 co-located cells use frequency groups spaced to give protection against adjacent channel interference. The use of end radiated cells allows for less co-channel interference, as well as providing for a more distinct handoff between cells. Coverage is improved by extending the footprints of the antennas in the end radiated cells, and by interleaving the footprints of antennas in adjacent cells. <IMAGE></p> |