Channel Assignment Techniques

First generation macrocellular systems typically use fixed channel assignment (FCA), where disjoint subsets of the available channels are permanently allocated to the cells in advance according to their estimated traffic loads. The cells are arranged in tessellating reuse clusters whose size is determined by the co-channel reuse constraint. For example, the North American AMPS system typically uses a 7-cell reuse cluster with 120° sectoring. The 12.5 MHz bandwidth allocation for AMPS can support a total of 416 two-way channels, 21 of which are control channels (one for each sector in a cluster), leaving a total of 395 traffic channels. This yields an allocation of 56 channels/cell with uniform FCA.