Performance Improvement of CDMA Hierarchical Cellular System with DAS Embedment in Macrocell

In this paper, a two-layer code division multiple access (CDMA) hierarchical cellular network structure is presented, which made up underlaid distributed antenna system (DAS) and overlaid macrocells. The analysis of coverage characteristic shows that embedding DAS instead of microcells in the macrocell makes network control and site engineering easier to be performed. Signal to interference ratio (SIR) of the macrocell/DAS is studied and compared with that of the macrocell/microcell system. Remote access unit (RAU) selection is employed to reduce the interference from the forward link in DAS. Simulation results show that performance of macrocell/DAS is superior to that of macrocell/microcell in the CDMA hierarchical system.