Résumé
The paper presents Monte Carlo simulations carried out during the preparatory phase of the Cherenkov Telescope Array project. The aim of the project is to build the next generation observatory of very high energy gamma rays. During the preparatory phase there is a need to optimize and verify design concepts for various elements of the array. In this paper we describe the main components of the software being used for that purpose, their functions and requirements. Preliminary results of the optimization of the small telescope - one of the several kinds intended for the array, are presented.