Facturacion in communication systems.

Billing method in communication systems, said method comprising the following steps: initiation of a procedure for establishment of communications using said communications resources susceptible billing of a first communication system (2) and a second communication system (1 ), providing at least one of said communication systems, wireless communication services; activation of a first process for obtaining a first charging component for the communications, the first component being associated billing the first communication system (2) and determined based on a first charging model; activating a second procedure for obtaining a second charging component for the communications, the second charging component to the second communication system (1) being associated and determined from a second charging model; obtaining first and second respective billing component from the first and second charging models; obtaining a total charge by combining the first and second charging components; and decreasing a prepaid balance during the course of communications from full charge; characterized by: activating the first and second procedures in a charging function (9, 10, 11) provided in one of the communication systems; and obtaining respective first and second charging components processing function simultaneously with the billing information associated with communication in the first and second communication systems.