  In this paper, we investigate the network utility maximization problem in
FDMA systems. We summarize with a suite of criteria on designing utility
functions so as to achieve the global optimization convex. After proposing the
general form of the utility functions, we present examples of commonly used
utility function forms that are consistent with the criteria proposed in this
paper, which include the well-known proportional fairness function and the
sigmoidal-like functions. In the second part of this paper, we use numerical
results to demonstrate a case study based on the criteria mentioned above,
which deals with the subcarrier scheduling problem with dynamic rate allocation
in FDMA system.
