Downlink admission control strategies for CDMA systems in a Manhattan environment

Downlink admission control strategies and downlink power control strategies, for CDMA systems in a Manhattan environment, are investigated by simulation experiments. Different admission policies are compared by investigating system capacity versus grade of annoyance, defined as a weighted combination of call blocking and call dropping probabilities, or by just viewing the call dropping probabilities. The admission decision is based on output power levels from base stations (BSs) and the investigation focuses on whether the admission decision should be based on measurements from one BS or measurements from several BSs. Simulations indicate that the admission algorithms do not gain much from using information from more than one cell. However, using information from more than one cell decreases the call dropping probability for very high loads. Further, the performances of the proposed downlink algorithms are not as good as for some previously studied uplink admission control algorithms. Finally, having a maximum output power constraint on a BS basis instead of on a channel basis decreases the call dropping probability.