Uplink and downlink capacity evaluations of a multi-tier CDMA mobile network employing directional handset antennas

The implementation of directional antennas within mobile handsets is highly attractive because it can effectively reduce the levels of intra-cell and inter-cell interference, mitigate the effects of multipath interference and lower the power absorbed into the user's head. In this paper, the link capacity of a two-tier model of an IS-95 based CDMA system is evaluated for both omni-directional and directional handsets. Soft-handoff shadow fading losses and imperfect uplink power control are included in the analysis to yield a more accurate evaluation of the system capacity. The results demonstrate that the spatial filtering properties of directional handsets have the potential to increase both the uplink and downlink system performance when compared to operation with conventional omni-directional handsets.