Abstract:
The invention relates to charging of a short message transmission in a telecommunications network. The invention provides a mechanism for refunding the subscriber for an already charged short message in the event of a failure during the delivery of that short message. The invention also relates to the methods and devices that are used to deliver a short message and perform the charging thereof.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field of the Invention 
         [0002]    The invention is related to a short message transmission in a telecommunications network. 
         [0003]    2. Description of Related Art 
         [0004]    In addition to speech connections, telecommunications networks provide data services like short message services (SMS). SMS allows the transmission of alphanumerical short messages of up to 160 ASCII characters from a sender to a receiver. 
         [0005]    To enable the transmission of a short message, the telecommunications network comprises a Short Message Service Centre (SMSC) that co-operates with Control Nodes such as the Mobile Services Switching Centre (MSC) or the Serving General Packet Radio System Support Node (SGSN). 
         [0006]    The SMSC is a node via which short messages are transmitted and can be stored for later transmission in the case the receiving party is not reached at a first attempt. Short messages are transmitted via one or more MSCs interfacing to the Short Message Service Centre: the SMS Inter-Working MSC (SMS-IWMSC) and the SMS Gateway MSC (SMS-GMSC). The term Inter-Working MSC refers to an MSC submitting mobile originated messages, and correspondingly, the term Gateway MSC refers to an MSC delivering mobile terminating short messages. 
         [0007]    In the state of the art, the charging of the transmission of a short message takes place when the short message has successfully arrived at the SMSC. The SMSC signals the successful receipt of the short message to a network node that is responsible for the initiation of the charging procedure. Said network node can be for example an MSC or a Service Control Point. The network node will initiate the creation of a Service Call Detail Record for the short message including a short message identifier and the amount that is charged for the transmission. The Call Detail Records are stored in a Call Detail Record Storage Unit. A Post-Processing Unit collects all Service Call Detail Records and calculates the actual billing of the short message transmission. An example of a possible implementation of the charging procedure is described in the PCT patent application WO03/024135. WO03/024135 relates to a method in a mobile telecommunications network of controlling charging procedures for message services which enable transport of messages from a sender to an SMSC, the method comprising transporting a message from the sender for example via a network node (MSC) to the SMSC, temporarily storing the message at the SMSC, sending a first confirmation acknowledging receipt of the message at an SMSC to the sender, and, if the sender acknowledges receipt of the first confirmation, routing the message from the SMSC to a recipient of the message and initiating a charging procedure for a message. 
         [0008]    The method of WO03/024135 has the shortcoming that the charging procedure for the short message is initiated as soon as the reception of the short message by the SMSC has been acknowledged. After the charging procedure has started, the short message is forwarded to the receiving party. However, the delivery of the short message to the receiving party might not be successful. One possible reason for failure of the delivery is that the receiver of the short message has not attached to the telecommunications network within a predefined time, i.e. the validity period of the short message, after the submission of the short message. This leads to the drawback that the subscriber is charged for short messages that cannot be delivered to the receiving party. 
       SUMMARY OF THE INVENTION 
       [0009]    It is an object of the invention to provide a charging mechanism that overcomes the drawbacks of the state of the art. 
         [0010]    This object is achieved by the methods of claim  1 , claim  2 , claim  3 , and of claim  4 , the Control Node of claim  9 , the Short Message Service Centre of claim  10  and the Post-Processing Unit of claim  12 . 
         [0011]    The invention provides a mechanism to refund the subscriber in the event of a failure during the delivery of the short message. To that end the invention involves the co-operation of a Control Node, a Short Message Service Centre and a Post-Processing Unit. Advantageously the Control Node can be a Mobile Services Switching Centre (MSC) or a Serving General Packet Radio System Support Node (SGSN). The invention relates the costs of a short message transmission that already have been charged to the subscriber, to a particular short message. The relation is established by including a short message identifier in each of the Service Call Detail Records and Delivery Failure Call Detail Records that are related to a short message transmission. The short message identifier is generated by the Control Node, which forwards the short message identifier towards the SMSC. The SMSC includes the short message identifier in a Delivery Failure Call Detail Record in the event of a failed delivery. Afterwards the SMSC forwards the Delivery Failure Call Detail Record towards the Post-Processing Unit. The Post-Processing Unit queries a Call Detail Record Storage Unit for Service Call Detail Records comprising the same short message identifier as included in the Delivery Failure Call Detail Record. The Post-Processing Unit calculates a refund amount for the failed short message transmission. The calculation is based on the information in the Delivery Failure Call Detail Record and the associated Service Call Detail Record. The invention allows the refund of a charged short message transmission in the event of the failure of the delivery towards the receiving party. 
         [0012]    The invention provides a method for refunding the costs of a failed short message transmission to a subscriber in a telecommunications network. The method comprises the steps of receiving a short message at a Control Node, the Control Node generating the short message identifier associated to the short message, the Control Node forwarding the short message to a Short Message Service Centre, a Call Detail Record Storage Unit receiving a Service Call Data Record, the Call Detail Record Storage Unit forwarding a Service Call Data Record to a Post-Processing Unit, the Short Message Service Centre forwarding the short message towards a receiving entity, the Short Message Service Centre detecting the failure of the delivery of the short message, the Short Message Service Centre generating a Delivery Failure Call Detail Record in the event of the failure of the delivery of the short message, the Short Message Service Centre forwarding the Delivery Failure Call Detail Record to the Post-Processing Unit, the Control Node forwarding the short message identifier to a Short Message Service Centre, the Short Message Service Centre including the short message identifier in the Delivery Failure Call Detail Record, the Post-Processing Unit calculating a refund amount for the failed short message transmission based on information in the Delivery Failure Call Detail Record and the Service Call Detail Record, and the Post-Processing Unit initiating the refund of the calculated refund amount to the subscriber, wherein the Delivery Failure Call Detail Record and the Service Call Detail Record comprise the short message identifier associated to the failed short message transmission. 
         [0013]    In an embodiment of the invention, the refund is implemented by initiating an Account Management Unit to increment an account associated to the subscriber with the calculated refund amount. 
         [0014]    In a further embodiment of the invention, the refund is implemented by initiating the correction of a bill associated to the subscriber in accordance with the calculated refund amount. 
         [0015]    The invention further provides a method implemented in a Control Node. The Control Node performs the steps of receiving a short message, generating a short message identifier associated to the short message, forwarding the short message, and forwarding the short message identifier to a Short Message Service Centre. 
         [0016]    The invention further provides a method implemented in a Short Message Service Centre. The Short Message Service Centre performs the steps of receiving a short message, forwarding the short message towards the receiving entity, detecting the failure of the delivery of the short message, generating a Delivery Failure Call Detail Record, forwarding the Delivery Failure Call Detail Record, receiving a short message identifier associated to the short message from a Control Node, and including the short message identifier in the Delivery Failure Call Detail Record. 
         [0017]    The invention further provides a method implemented in a Post-Processing Unit. The Post-Processing Unit performs the steps of receiving a Delivery Failure Call Detail Record from a Short Message Service Centre, receiving a Service Call Detail Record from a Call Detail Record Storage Unit, calculating a refund amount for the failed short message transmission based on the information in the Delivery Failure Call Detail Record and the Service Call Detail Record and initiating the refund of the calculated refund amount to the subscriber, wherein the Delivery Failure Call Detail Record and the Service Call Detail Record comprise a short message identifier associated to the failed short message transmission. 
         [0018]    In an embodiment of the invention, the Control Node is a Mobile Services Switching Centre or a Serving General Packet Radio System Support Node. 
         [0019]    In a further embodiment of the invention, the receiving entity is a Service Node or a subscriber. 
         [0020]    The invention further provides a Control Node for a telecommunications network. The Control Node comprises an input unit for receiving a short message, a processing unit for controlling further units, an identifier generating unit for generating a short message identifier associated to the short message and an output unit for forwarding the short message. The processing unit is arranged to initiate the output unit to forward the short message identifier to a Short Message Service Centre. 
         [0021]    The invention further provides a Short Message Service Centre for a telecommunications network. The Short Message Service Centre comprises an input unit for receiving a short message, a processing unit for controlling further units, a call detail record generating unit for generating a Delivery Failure Call Detail Record, an output unit for forwarding the short message and for forwarding the Delivery Failure Call Detail Record and detecting means for detecting the failure of the delivery of the short message and informing the processing unit thereof. The input unit is arranged to receive a short message identifier from a Control Node. The processing unit is arranged to initiate the call detail record generating unit to include the short message identifier in the Delivery Failure Call Detail Record. 
         [0022]    In an embodiment of the invention the Control Node is a Mobile Services Switching Centre or a Serving General Packet Radio System Support Node. 
         [0023]    The invention further provides a Post-Processing Unit for a telecommunications network. The Post-Processing Unit comprises an input unit for receiving a Delivery Failure Call Detail Record and for receiving a Service Call Detail Record, a processing unit for controlling further units and an output unit for forwarding messages. The processing unit is arranged to calculate a refund amount for a failed short message transmission to a subscriber based on information in the Delivery Failure Call Detail Record and the Service Call Detail Record. The processing unit is further arranged to initiate the refund of the calculated refund amount to the subscriber. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    In the following the invention will be described by way of figures and embodiments with reference to the attached drawings, in which: 
           [0025]      FIG. 1  shows a schematic overview of the components of a telecommunications system according to an embodiment of the invention. 
           [0026]      FIG. 2  shows a sequence diagram illustrating a possible sequence of steps for a short message transmission according to the invention. 
           [0027]      FIG. 3  shows a flow diagram illustrating a sequence of process steps according to the invention as performed by a Control Node. 
           [0028]      FIG. 4  shows a flow diagram illustrating a sequence of process steps according to the invention as performed by a Short Message Service Centre. 
           [0029]      FIG. 5  shows a flow diagram illustrating a sequence of process steps according to the invention as performed by a Post-Processing Unit. 
           [0030]      FIG. 6  shows a Control Node for use within a telecommunications network according to the invention. 
           [0031]      FIG. 7  shows a Short Message Service Centre for use within a telecommunications network according to the invention. 
           [0032]      FIG. 8  shows a Post-Processing Unit for use within a telecommunications network according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    The present invention can be implemented in any mobile telecommunications network providing a short message service. In the following description of preferred embodiments with reference to  FIG. 1 , the invention is set forth with respect to a mobile telecommunications network with Mobile Services Switching Centre-switched SMS capabilities and optionally, with a prepaid service running in a Service Node  102 , such as a Service Control Point (SCP). The invention may also be implemented for post-paid subscribers. The differences in handling the charging of a short message transmission between pre-paid and post-paid subscribers will be mentioned where applicable. A Mobile Services Switching Centre  101  receives a short message transmitted by a sending party  110 . For pre-paid subscribers the Mobile Services Switching Centre  101  invokes the prepaid service. The service logic of the prepaid service takes care of the proper charging of the short message transmission to the account of the subscriber to be charged. The account information is stored in an Account Management Unit  107 , such as a Service Data Point or another suitable database arranged to retrieve and update account information. For billing purposes in the case of a pre-paid subscriber a Service Node  102  sends charging information to a Call Detail Record Storage Unit  105  where Call Detail Records are stored and can be retrieved for further processing by a Post-Processing Unit  106 . For post-paid subscribers the Mobile Services Switching Centre  101  generates a Service Call Detail Record and sends it to the Call Detail Record Storage Unit  105 . A Short Message Service Centre (SMSC)  104  is a node via which short messages are transmitted and can be stored for later transmission in the case the receiving party is not reached at a first attempt. Short messages are transmitted via one or more MSCs interfacing to the Short Message Service Centre: in the present embodiment an SMS Inter-Working MSC (SMS-IWMSC)  103  and an SMS Gateway MSC (SMS-GMSC)  109 . The term Inter-Working MSC refers to an MSC submitting mobile originated messages, and correspondingly, the term Gateway MSC refers to an MSC delivering mobile terminating short messages. The SMS-IWMSC  103  may be physically integrated with the SMSC or with the MSC for the sending party. The SMS-GMSC  109  receives short messages from the SMSC, interrogates a Home Location Register (HLR)  108  of a receiving party  111  for routing information to deliver each short message and forwards each short message to the serving MSC (not depicted) for delivery to the receiving party  111 . The SMS-GMSC  109  may be physically integrated with the SMSC or with the MSC for the receiving party. 
         [0034]      FIG. 2  shows a failed short message transmission for which a number of steps are carried out in order to refund the costs for the transmission according to the invention. Sender  201  submits a short message in a step  221  to Control Node  202 . The short message comprises an identification of the sending party and the receiving party. The Control Node  202  generates a short message identifier associated to the short message. Steps  222  to  225  are applicable to pre-paid subscribers. In a step  222  the Control Node  202  invokes a prepaid service by sending a message to a Service Node  203 . The message comprises the short message identifier and the identification of the sending and the receiving party. The Service Node  203  interrogates an Account Management Unit  208  in a step  223  to check the balance of the account and reserves funds for the transmission of the short message. The Account Management Unit  208  responds in a step  224  confirming that. The account could belong either to the sender or the receiver of the short message or even a third party. The Service Node  203  sends an instruction to the Control Node  202  in a step  225  to continue the transmission of the short message. The Control Node  202  forwards the short message in a step  226  and the short message identifier in a step  227  to a Short Message Service Inter-Working MSC (SMS-IWMSC)  204 . In an embodiment of the invention steps  226  and  227  are implemented as a single step. The SMS-IWMSC  204  forwards the short message in a step  228  and the short message identifier in a step  229  to a serving Short Message Service Centre  205 , preferably steps  228  and  229  are implemented as a single step. The Short Message Service Centre  205  receives the short message and the short message identifier and confirms to the Control Node  202  in a step  230  that the short message was accepted. For pre-paid subscribers the Control Node  202  signals to the Service Node  203  the successful submission of the short message to the Short Message Service Centre in a step  231 . Steps  230  and  231  are optional steps. For pre-paid subscribers the Service Node  203  instructs the Account Management Unit  208  to decrement the account of the subscriber with an appropriate amount for the short message transmission, not depicted, and in a step  232  instructs a Call Detail Record Storage Unit  206  to create a Service Call Detail Record comprising the charged amount and the short message identifier. For post-paid subscribers the Control Node  202  creates the Service Call Detail Record comprising the charged amount and the short message identifier, not depicted. The Short Message Service Centre  205  forwards the short message to a Short Message Service Gateway MSC (SMS-GMSC)  209  in a step  233 . The SMS-GMSC  209  forwards the short message in a step  234  to the Control Node  210  serving the receiving party  211 . In this embodiment the Control Node  210  detects that the short message cannot be delivered to the receiver  211 , e.g. the terminal of the receiving party is detached from the telecommunications network, and signals the failure to the SMS-GMSC  209  in a step  235 . The SMS-GMSC forwards the information to the Short Message Service Centre  205  in a step  236 . The Short Message Service Centre  205  repeatedly attempts a subsequent delivery of the short message towards the receiving party, not depicted, until the validity period of the short message expires and then produces a Delivery Failure Call Detail Record comprising the short message identifier and forwards the record in a step  237  to a Post-Processing Unit  207 . The Post-Processing Unit  207  requests the Call Detail Record Storage Unit  206  to send the Service Call Detail Record corresponding to the transmission in a step  238 ; and the Call Detail Record Storage Unit  206  sends the corresponding Service Call Detail Record in a step  239 . The Post-Processing Unit  207  calculates the amount to be refunded based on the contents of the matching Delivery Failure Call Detail Record and Service Call Detail Record. For pre-paid subscribers the Post-Processing Unit  207  instructs the Account Management Unit  208  to increment the subscriber account with the refund amount in a step  240 . For post-paid subscribers the Post-Processing Unit  207  initiates the correction of a bill associated to the subscriber in accordance with the calculated refund amount, not depicted. 
         [0035]      FIG. 3  depicts a possible sequence of steps performed by a Control Node when processing the transmission of a short message according to the invention. After the submission of a short message by a Sender in a telecommunications network the Control Node receives the short message in a step  301 . In a step  302  the Control Node generates a short message identifier associated to the short message, which identifies the short message. The short message identifier preferably consists of the address of the Control Node accompanied by a unique short message reference number. The mechanism of generating a short message reference number is a standard mechanism, which has been specified for example in 3GPP TS 23.078, V3.18.0 (3GPP Release 99, publication date 2003-09-29). The Control Node forwards the Short Message in a step  303  and the Short Message Identifier in a step  304  towards the Short Message Service Centre. It is possible to send both the short message and the short message identifier in a single message, for example a Mobile Application Part (MAP) message. 
         [0036]      FIG. 4  depicts a possible sequence of steps performed by a Short Message Service Centre when processing the transmission of a short message according to the invention. After the Control Node has forwarded the short message and the short message identifier, the Short Message Service Centre receives the short message in a step  401  and the short message identifier in a step  402 . As said for  FIG. 3 , it is possible to receive both the short message and the short message identifier in a single message, for example a Mobile Application Part (MAP) message. In a step  403  the Short Message Service Centre forwards the short message towards the receiving entity. In a step  404  the Short Message Service Centre receives a message from an SMS-GMSC indicating that the transmission towards the receiving entity failed. The Short Message Service Centre repeatedly attempts a subsequent delivery of the short message towards the receiving party until the validity period of the short message expires. Alternatively, the Short Message Service Centre requests a Home Location Register to notify the Short Message Service Centre when the receiving entity becomes available for receiving the short message. When the validity period of the short message expires before successful delivery, the Short Message Service Centre produces a Call Detail Record indicative of the failed delivery of the short message, the so-called Delivery Failure Call Detail Record, in a step  405 . According to the invention the Short Message Service Centre includes the previously received short message identifier in the Delivery Failure Call Detail Record in a step  406  and forwards the Delivery Failure Call Detail Record towards a Post-Processing Unit in a step  407 . 
         [0037]      FIG. 5  depicts a possible sequence of steps performed by a Post-Processing Unit for refunding the costs of a failed transmission of a short message according to the invention. The Post-Processing Unit receives the Delivery Failure Call Detail Record in a step  501 . In a step  502  the Post-Processing Unit requests the Call Detail Record Storage Unit to transmit the corresponding Service Call Detail Record, i.e. the Service Call Detail Record that includes a short message identifier identical to the short message identifier received in the Delivery Failure Call Detail Record in step  501 . The Service Call Detail Record indicates among others the amount that has been charged already to the account of the subscriber paying for the short message transmission. The Post-processing Unit receives the Service Call Detail Record in a step  503 . When the Post-Processing Unit obtains the Service Call Detail Record, it calculates in a step  504  how much of the charged amount is to be refunded. The amount to be refunded preferably depends on other parameters given in the Service Call Detail Record. For example such parameters may indicate that the total of the charged amount is to be refunded, or as another example only a part, say 90 percent, of it. In a step  505  the Post-Processing Unit initiates the refund of the subscriber with the calculated refund amount. For pre-paid subscribers the Post-Processing Unit sends an instruction to increment the subscriber account together with the resulting refund amount to the Account Management Unit. For post-paid subscribers the Post-Processing Unit initiates the correction of a bill associated to the subscriber in accordance with the calculated refund amount. 
         [0038]    In  FIG. 6  a Control Node  601  according to an embodiment of the invention is depicted. The Control Node  601  comprises an input unit  602  for receiving short messages, a processing unit  603  for controlling further units, an output unit  604  for sending messages and an identifier generating unit  605  for generating a short message identifier. The units  602  to  605  can be implemented in hardware or software or a combination of both. The input unit  602  receives a short message. The processing unit  603  instructs the identifier generating unit  605  to generate a short message identifier associated to the short message and instructs the output unit  604  to send the short message identifier and the short message to a Short Message Service Centre. The identifier generating unit  605  generates a short message identifier. The output unit  604  sends the short message and the short message identifier to the Short Message Service Centre. 
         [0039]    In  FIG. 7  a Short Message Service Centre  701  according to an embodiment of the invention is depicted. The Short Message Service Centre  701  comprises an input unit  702  for receiving messages, a processing unit  703  for controlling further units, an output unit  704  for sending messages, a Call Detail Record generating unit  705  for generating Call Detail Records and detecting means  706  for detecting the failure of the delivery of a short message. The units  702  to  706  can be implemented in hardware or software or a combination of both. According to the invention the input unit  702  is adapted to receive the short message identifier from a Control Node. The output unit is arranged to send the short message towards a receiving entity. The detecting means  706  is arranged to detect a delivery failure, e.g. by receiving a failure message. The processing unit  703  is arranged to initiate to initiate a reattempt of the transmission as explained in the description of  FIG. 4 . The processing unit  703  is arranged to instruct the Call Detail Record generating unit  705  to create a Delivery Failure Call Detail Record comprising the short message identifier and to instruct the output unit  704  to send the Delivery Failure Call Detail Record to a Post-Processing Unit. The Call Detail Record generating unit  705  is arranged to create a Delivery Failure Call Detail Record comprising the short message identifier. The output unit  704  is arranged to send the Delivery Failure Call Detail Record to the Post-Processing Unit. 
         [0040]    In  FIG. 8  a Post-Processing Unit  801  according to an embodiment of the invention is depicted. The Post-Processing Unit  801  comprises an input unit  802  for receiving Service Call Detail Records and for receiving Delivery Failure Call Detail Records, a processing unit  803  for controlling further units and an output unit  804  for sending messages. The units  802  to  804  can be implemented in hardware or software or a combination of both. According to an embodiment of the invention, the input unit  802  receives a Delivery Failure Call Detail Record comprising a short message identifier. The processing unit  803  requests a Call Detail Record Storage Unit to send a Service Call Detail Record corresponding to the Delivery Failure Call Detail Record, i.e. comprising an identical short message identifier. The input unit  802  receives the Service Call Detail Record. The processing unit calculates a refund amount based on the contents of the corresponding Service Call Detail Record and the Delivery Failure Call Detail Record. For pre-paid subscribers the processing unit  803  instructs an Account Management Unit to increment a subscriber account with the refund amount. For post-paid subscribers the processing unit  803  initiates the correction of a bill associated to the subscriber in accordance with the calculated refund amount.