Third generation network (UMTS) is aiming at the realisation of a global coverage and seamless services with enormous variety of applications and interactive services. One of their service objectives is to achieve global roaming of UMTS users, and hence provide rapid deployment of UMTS services over large geographical areas so increase the development of telecommunication services in growing and developing countries. To achieve this goal, satellite component will play a primordial role in order to extend and enhance the existent UMTS terrestrial radio access network (UTRAN), so it will be referred to as UMTS satellite radio access network (USRAN) . UMTS involves a satellite segment which complements the terrestrial one to offer a global mobile communication service. In this paper we describe two alternatives network architectures for satellite integration with UMTS terrestrial radio access network and their respective protocols stacks. Performance analysis and testing were done using NS2 simulator for voice application as well as for data transfer application.