Universal Mobile Telecommunication System (UMTS) is in growth through enormous variety, of applications and interactive services. In this work we propose a complement services and a complete access anywhere and any time to the UMTS services. UNITS involves a satellite segment which complements the terrestrial one to offer a global mobile communication service. The satellite component aims to extend and enhance the existent UNITS Terrestrial Radio Access Network (UTRAN), so it will be referred to as UMTS Satellite Radio Access Network (USRAN). In this paper Alternatives architecture scenarios are proposed and analysed with their respective protocols stack and performance testing.