... The optimization objective is the maximization of therate function (RM case) , or the minimization of the powerfunction (MM case) , subject to a set of constraint func-tions that reflect system ... exist exact conditions for their equivalence, as in thewater-filling case. Theorem 1 developed in Section 3.3 holdsalso for the case of discrete loading, where the only differ-ence is that due to ... constraintsare met, that is, the total power budget is consumed for theRM case or the target data rate is achieved for the MM case. At the end of the greedy process, the respective objective issatisfied,...