A Picocellular CDMA/TDD Overlay on GSM

Abstract

To improve the utilisation of frequency bands assigned to GSM system, an idea of CDMA overlay seems to be interesting. In this paper a picoceUular CDMAfIDD overlay on GSM system has been considered. It is corresponding to a TDD mode ofWCDMA proposed by ETSI, ARIB and TIA for the future third generation UMTSlIMT2000 system. The overlay is proposed for indoor operation in the area of macrocell of GSM system. As it turns out the implementation of overlay can significantly increase the spectrum efficiency in the frequency band that is shared by GSM system and the overlay. The picocellular CDMAfIDD overlay can be used both for speech and data transmission.