6th International ICST Symposium on Modeling and Optimization

Research Article

Nonconcave Utility Maximization in the OFDMA Downlink

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  • @INPROCEEDINGS{10.4108/ICST.WIOPT2008.3207,
        author={Johannes Brehmer and Wolfgang Utschick},
        title={Nonconcave Utility Maximization in the OFDMA Downlink},
        proceedings={6th International ICST Symposium on Modeling and Optimization},
        keywords={Downlink Lagrangian functions Power system modeling Resource management Signal processing algorithms System performance Traffic control Video codecs Video signal processing Wireless networks},
  • Johannes Brehmer
    Wolfgang Utschick
    Year: 2008
    Nonconcave Utility Maximization in the OFDMA Downlink
    DOI: 10.4108/ICST.WIOPT2008.3207
Johannes Brehmer1,*, Wolfgang Utschick1,*
  • 1: Associate Institute for Signal Processing, Technische Universitat Munchen
*Contact email: brehmer@tum.de, utschick@tum.de


The problem of utility maximization in an OFDMA downlink is considered. Based on measurements of a scalable video codec, concave and nonconcave utility functions are proposed. Two approaches to solving the utility maximization problem in a modular fashion are considered, one based on Lagrange duality, the other based on a projected gradient algorithm. Both methods yield the optimum solution for concave utilities. In the nonconcave case, simulation results show almost identical performance for both methods under the assumption that the dual solution is found. In contrast, the dual approach fails if the dual subproblems can only be solved to local optimality.