Generation of electromagnetic radiations from the nonlinear interaction of whistler solitons with the upper hybrid waves is investigated. The power emitted from the right-hand polarized fundamental whistler sideband of upper hybrid frequency is obtained. The results are applied to the generation of auroral kilometeric radiations (AKR) on the auroral field lines in the earth's magnetosphere. The power is found to be larger in the plasma depletion region as compared to high-density region. It is found that about 103--104 whistler solitons filling a volume of ≲4¿102 km3 in a region of field-aligned auroral cavity can generate the observed AKR power of 109 W. Theoretical predictions agree very well with the observed properties of AKR, e.g., frequency range, polarization, peak power and its tendency to occur in the density depletion regions.