Joint transmitter adaptation and power control in multi-user wireless systems with target SIR requirements

In this paper we study joint transmitter adaptation and power control in multiuser wireless systems with multipath channels and target values imposed on the users´ signal-to-interference+noise-ratio (SINR) at the receiver. We use a general framework that is applicable to a wide range of wireless systems and scenarios to cast this as a distributed constrained optimization problem, and study necessary conditions that must be satisfied by the optimal solution. We also present an incremental algorithm that adapts user transmitters and power values in a distributed fashion until a fixed point is reached where the specified target SINRs are achieved with minimum transmitted power. Convergence of the proposed algorithm is discussed, and the algorithm is illustrated with numerical examples obtained from simulations.