Upper-bound Analysis of Cellular Channel Capacity

In cellular communication systems, the same carrierfrequency is re-used at spatially separated base stations (BSs) to efficiently utilize the limited bandwidth. Therefore, the channel capacity is limited by the co-channel interference (CCI) from the neighboring co-channel BSs. To reduce the CCI, it is necessary to increase the frequency-reuse factor (the number of different channel groups). However, the available bandwidth per BS becomes narrower and hence, the cellular channel capacity reduces. In this paper, we derive a simple upper-bound formula for the cellular channel capacity for the given frequency-reuse factor in an interference-limited environment assuming the worst case scenario (i.e., the mobile station of interest is located at the cell edge). Both the path loss and the log-normally distributed shadowing loss are taken into account. The derived formula predicts that the optimum frequency-reuse factor which maximizes the worst case cellular channel capacity is F=3~4 irrespective of the path loss exponent and shadowing standard deviation. This is confirmed by the computer simulation. Keywords-component; cellular system; channel capacity cochannel reuse; frequency-reuse factor