The cellular concept solves spectral congestion issues by reusing radio channels in different hexagonal cells. Hexagonal cells provide full coverage with minimal cells and equal distance between cell centers. Each cell is assigned a group of channels to limit interference between neighboring cells using frequency planning. The capacity of the system increases with the number of times the frequency plan can be reused across different cell clusters.

1. The Cellular Concept

4. Possible cell structures

12. Signal strength in Handoff process