The fourth generation mobile communication systems will evolve either towards generalized high bandwidth radio systems or complete integration of communication infrastructures with a seamless roaming capability. The choice between these both trends will be mainly directed by the kind of services the customers will wish to use in priority, more than by technical considerations. At the end of the day, economic constraints will decide and it can be expected that strong arguments will be necessary to justify the very huge investments which could be required depending on the final choice, in any case, however, the complexity of the system will necessitate increasing research efforts and innovative solutions, and it is expected that cooperation between the main actors will play a major role in the future.