A performance comparative study on the implementation methods for OFDMA cross-layer optimization

One key issue in cross-layer optimization techniques for next-generation multi-user orthogonal frequency division multiple access (OFDMA)-based broadband wireless network systems lies in the implementation methods of optimal resource scheduling. In the literature the optimal solutions are derived either through dynamic programming (referred to as a purely numerical approach) or via mathematical analysis (referred to as an analytical approach). When the latter approach is adopted, an additional iterative process is usually needed for the final optimal solution to be obtained. This paper presents a first in-depth comparative study on the implementation performance between the analytical and the numerical techniques. For this purpose, various popular iterative methods and numerical methods are investigated in our study. Several performance metrics (e.g., achieved overall data rate, absolute approximation error, and computational time) are utilized for comparison. Our simulation results demonstrate clearly that the analytical approaches indeed outperform the numerical ones. Furthermore, regarding different iterative methods, it is shown that the semi-implicit root (SIR) mechanism performs best in terms of the convergence rate, the root-finding accuracy, and the computational time.

► In-depth comparative study between analytical and numerical methods for OFDMA.
► Investigate various iterative and numerical methods for cross-layer optimization.
► Various performance metrics are utilized for comparison.
► Results demonstrate analytical approaches outperform numerical ones.
► SIR performs best in convergence rate, accuracy and computational time.