2.5. Estimation of the number of physical radio channels in an arbitrary GSM cell

The number of physical channels in an arbitrary cell (let's call the cell capacity) of the GSM standard is determined by the type of frequency reuse model.
As an example, consider the calculation of cell capacity for the Motorola network model (Fig. 2.9): since each of the two adjacent cells of the model uses different groups of carrier frequencies, the capacity of an arbitrary network of such a network is:

Ki = (124/2) -8 = 496 physical channels (where the number 124 is the number of duplex

radio channels 124 = (25 MHz / 0.2 MHz) - 1), and the number 8 is the number of physical channels in one duplex radio channel (radio channel).

Thus, in each sector of the network, on average, 496/6 ~ 82 physical radio channels should be formed.
In the model of fig. 2.8 different groups of carrier frequencies are used in three adjacent cells, therefore cell capacity will be: Kt- (124/3) * 8 = 328 physical channels.

Thus, depending on the GSM mobile network structure, the capacity of the cell, that is, the number of physical channels, and ultimately the number of served mobile subscribers, will vary.