TDD-CDMA extension to FDD-CDMA based third generation cellular system

A TDD-CDMA extension for a FDD-CDMA based third generation cellular system is considered in this paper, A system scenario is presented where frequency bands allocated to time division duplex (TDD) operation can be effectively utilized in complementing the services and increasing the capacity provided by a wide area coverage frequency division duplex (FDD) system. A flexible and simple TDD air interface capable of allocating capacity asymmetrically between the uplink and downlink is considered. Such an air interface is well suited for providing asymmetric high bit rate services. Intercell, intracell and interoperator interference problems in the asymmetric TDD-CDMA system are identified. Network complexities in FDD and TDD systems are analyzed.