We perform a study of O-16+O-16 fusion at above and below the interaction barrier energies using threedimensional time-dependent Hartree-Fock (TDHF) calculations at above-barrier energies and density-constrained TDHF calculations for the entire energy range. We discuss the variations of the experimental data at above the barrier energies. Calculations reasonably reproduce the observed energy-dependent broad oscillations in the fusion excitation functions. These oscillations result from overcoming L-dependent fusion barriers. The role of the coupling to low-lying octupole states is also discussed.