Fee Versus Royalties in General Cost functions

Which is better off for the patentee to license its technology by fixed fee or unit royalties? Kamien and Tauman [8] showed that the fixed fee scheme brings greater private value of the patent in the linear model. We extend their analysis into a general model. Then, the simple fact that the model allows a increasing marginal cost supports the unit royalties scheme. More concretely, the unit royalties scheme is superior to the fixed fee scheme when the number of firms is large.