nd GSM cellular services already existed. Thuraya, a network operator servicing the United Arab Emirates and ACEs servicing Asia were two examples. Hybrid satellite/terrestrial systems are different in that they use terrestrial repeaters to combine the wide-area coverage capabilities of satellites with the urban coverage and in building capabilities provided from terrestrial networks. These may or may not be associated with existing cellular or terrestrial broadcast networks. The terrestrial repeaters are described in the US as ancillary terrestrial components (ATC) and in Europe and Asia as ground-based components. In China the networks are described as satellite and terrestrial interactive multiservice infrastructure (STiMI). Hybrid networks were already used in the US to deliver audio broadcasting for in-car and in-flight entertainment. Widespread deployments of these systems were planned both for audio and TV broadcasting and for two way cellular service provision. These deployments exploited already allocated L Band and S Band spectrum in US and rest of the world markets. Some of this spectrum has been gifted to the operators. Typically these allocations are not owned by traditional terrestrial cellular or terrestrial broadcast service providers. As such, they represented a competitive threat and by implication a collaborative opportunity for the cellular network operator and traditional terrestrial broadcast community. Present S band satellite spectral allocations are shown in Table 16.11. Their relationship to cellular allocations above and below 2 GHZ are shown in Table 16.12. Hybrid networks were, and possibly are, an integral part of the convergence presently taking place between satellite and terrestrial cellular, TV broadcast and broadband and narrowband data-delivery systems. This convergence offers positive crossover value opportunities but these opportunities need to be qualified within the present and future context of the satellite industry. They also need to be technically efficient. If a networ