Co-channel interference and capacity for two-tier CDMA cellular systems

The CDMA system has the potential to provide more capacity than other systems and the hierarchical layer of cells will be popular in the future. However, the problem is whether the same RF channels used in CDMA overlayed/underlayed macrocell and microcell structures also obtain high capacity as in the homogeneous structure. This paper will investigate the uplink and downlink interference of microcell and macrocell systems under hierarchical conditions. The pilot signal and power control for downlinks are also considered. We use analytical and simulation methods to investigate the problem. However the results are discouraging. The capacity of microcells and macrocells is limited by the downlink and uplink respectively