Optimization of SIC Receiver and CDMA Power Control by Discrete Stochastic Approximation

In an uplink CDMA transmission, we consider a base station that utilizes successive interference cancellation (SIC) and performs power control of the mobile terminals to minimize the system power. Since the joint optimization of power control and ordering (JOPCO) detection in SIC requires a computational effort that grows exponentially with the number of active users, in this paper we propose an approximated solution obtained by modelling JOPCO as a discrete stochastic optimization problem. The proposed algorithm is based on the construction of a Markov chain whose states are the orderings. Moreover, in order to further reduce complexity, an efficient description of the state probabilities is derived. Simulations performed on an UMTS scenario show that the proposed technique yields a performance close to the optimal JOPCO solution