Effect of the cell size and the path loss model on the GSM Erlang capacity for microcellular environments

The reuse efficiency in TDMA microcellular systems using frequency hopping (FH), power control (PC), and discontinuous transmission (DTX), is evaluated in the literature, a two-slope propagation model for microcellular environments is widely reported. The effects of the propagation model parameters on both the average signal to interference ratio (SIR) and the reuse efficiency are investigated. As it is expected, reducing the cell radius increases the cell's Erlang capacity per area unit. However, this cell radius reduction implies an increase in the co-channel interference level and then a higher reuse factor may be required. Our main contribution is to observe that the system performance is extremely sensitive on the propagation model parameters and depends strongly on the cell size and reuse factor. Also, the capacity increase because of cell radius reduction combined with dynamic channel assignment strategies is evaluated in a TDMA system without FH, PC, nor DTX.