Power control and QoS of a CDMA based hierarchical cell structure network

The hierarchical cell structure is needed for different requirements: large cells guarantee continuous coverage, while small cells are necessary to achieve good spectrum efficiency and high capacity. In this paper a CDMA system in macro/micro cell structure is investigated. We propose an adaptive scheme of controlling cell size according to time-varying traffic distribution in a macro/micro overlaid cell environment. This aims to bring communications quality in both macro-cell and micro-cell to a target quality level. Simulation results show that the proposed scheme effectively controls the time-varying traffic fluctuations and provides an enhanced performance