A mobile digital cellular telecommunication system comprising a network component (505, 506, 507, 508) configured to generate call detail records (CDRs), a real time event driven rating system (501, 502) and a batch processing system, the real time event driven rating system comprising a rating component (501a, 502a) having an interface for inputting the CDRs and being configured for rating an inputted CDR, the real time event driven rating system being configured to perform the following steps in response to receiving of a CDR from the network component for a telecommunication service provided to a user (510, 511): • forwarding the received CDR to the batch processing system if the received CDR is related to a postpaid account of the user; and • performing the following steps if the received CDR is related to a prepaid account of the user: ∘ inputting the received CDR into the rating component for determining a charge amount for the received CDR, ∘ adding to the received CDR the determined charge amount, ∘ after the adding to the received CDR the determined charge amount forwarding the received CDR to the batch processing system, and ∘ charging the prepaid account by the charge amount; and the batch processing system being configured to perform the steps of: • receiving the forwarded CDR, and • storing the received CDR in a database; in response to receiving a rating request to rate the prepaid account in the time interval specified in the rating request the batch processing system being further configured to perform the following steps: • querying the database for retrieval of CDRs related to the prepaid account and their respective charge amounts which were received in said time interval, • calculate a preliminary overall charge amount of the retrieved CDRs related to the prepaid account, • modify the retrieved CDRs related to the prepaid account according to rating rules related to the prepaid account, • generating an event record related to the prepaid account, the event record related to the prepaid account comprising the modified CDRs related to the prepaid account and the preliminary overall charge amount, and • sending the event record related to the prepaid account to the real time event driven rating system; the real time event driven rating system being further configured to perform the following steps in response to receiving the event record related to the prepaid account from the batch processing system: • inputting the modified CDRs comprised in the received event record related to the prepaid account into the rating component for determining a final overall charge amount for the modified CDRs comprised in the event record related to the prepaid account, • updating a remaining credit of an account balance of the prepaid account according to a difference between the preliminary and the final overall charge amount, and • sending a billing message related to the prepaid account to the batch processing system comprising the final overall charge amount. • forwarding the received CDR to the batch processing system if the received CDR is related to a postpaid account of the user; and • performing the following steps if the received CDR is related to a prepaid account of the user: ∘ inputting the received CDR into the rating component for determining a charge amount for the received CDR, ∘ adding to the received CDR the determined charge amount, ∘ after the adding to the received CDR the determined charge amount forwarding the received CDR to the batch processing system, and ∘ charging the prepaid account by the charge amount; and ∘ inputting the received CDR into the rating component for determining a charge amount for the received CDR, ∘ adding to the received CDR the determined charge amount, ∘ after the adding to the received CDR the determined charge amount forwarding the received CDR to the batch processing system, and ∘ charging the prepaid account by the charge amount; and • receiving the forwarded CDR, and • storing the received CDR in a database; • querying the database for retrieval of CDRs related to the prepaid account and their respective charge amounts which were received in said time interval, • calculate a preliminary overall charge amount of the retrieved CDRs related to the prepaid account, • modify the retrieved CDRs related to the prepaid account according to rating rules related to the prepaid account, • generating an event record related to the prepaid account, the event record related to the prepaid account comprising the modified CDRs related to the prepaid account and the preliminary overall charge amount, and • sending the event record related to the prepaid account to the real time event driven rating system; • inputting the modified CDRs comprised in the received event record related to the prepaid account into the rating component for determining a final overall charge amount for the modified CDRs comprised in the event record related to the prepaid account, • updating a remaining credit of an account balance of the prepaid account according to a difference between the preliminary and the final overall charge amount, and • sending a billing message related to the prepaid account to the batch processing system comprising the final overall charge amount.