Brand/product innovation and the optimal length of trademark/patent protection

A simple CES model of product differentiation is used to consider brand innovation and compulsory trademark licensing. Judd has used a different but closely related model to study product innovation and optimal patent length. Under Cournot assumptions, computer simulations show that the optimal length of trademark/patent protection is finite and varies in an intuitive way with the costs of innovation and production, interest rates and taste parameters.