In Fig. 1, the base stations in the mobile network are partitioned into a triangle network using the triangulation
method.
In the triangle network, a site layer can be defined as the length of the shortest path between two cells. For example, assume cell A is a serving cell.
The shortest path from cell B to cell A is 1, so cell B is in site layer 1.
The shortest path from cell C to cell A is 2, so cell C is in site layer 2 and cell D also is in site layer 2.
This type of partitioning result has been verified in the real world experience.