Method, system and server for charging a prepaid account

A method for charging a prepaid account, comprising:

• reserving, by an authentication, authorization, and accounting (AAA) server, fees for one accounting period and delivering, available traffic for the accounting period, for a user who sends a Radius Access-Request message, to a network access server (NAS) based on an available balance of a prepaid account shared by the user and other users in response to a successful authentication of the user's access request when the available balance of the prepaid account is greater than or equal to the communication fees required for the one accounting period;
• and
• delivering, by the AAA server, the available traffic for the next accountinq period for the user to the NAS based on the available balance of the prepaid account shared by the user and other users in response to a receipt of an Accounting-Request-Interim message from the NAS when the available balance of the prepaid account is qreater than or equal to the communication fees required for the next accountinq period.