Downlink transmit power minimization in power-controlled multimedia CDMA systems

Since in CDMA systems, to transmit with less power is essential for reducing neighbor cell interferences as well as saving battery of user terminals, transmit power minimization problem is an important issue to be considered. In [1], the model of transmit power minimization problem in CDMA systems uplink is presented. In this paper, we first review previous work, then investigate the transmit power minimization in CDMA systems downlink. The sufficient and necessary conditions for the existence of the feasible solutions are analyzed. We also provide the optimal solutions to uplink and downlink models. The optimal solutions can be used as a reference for power control and radio resource allocation in multimedia CDMA systems.