Abstract:
The present invention relates generally to mobile communication systems, methods and apparatus for transmitting messages from an originating party to a receiving mobile station, and transmitting short message service (SMS) messages from an originating party to a receiving mobile station in a mobile communication system. Briefly, the present invention solves a problem by transmitting both a message and a validity period ( 401 ) associated with the message from the message center to the receiving mobile station. By transmitting both a message and a validity period ( 401 ), associated with the message, where the validity period ( 401 ) specified by the sender of the message, the receiving mobile station can use the validity period ( 610 ) information when making decisions on how to process the received message.

Description:
This application claims the benefit of the filing date of Swedish patent application number 0002766-4 filed on Jul. 21, 2000 and PCT application number PCT/SE01/01315 filed on Jun. 8, 2001. 
   TECHNICAL FIELD OF THE INVENTION 
   The present invention relates generally to mobile communication systems, methods and apparatus for transmitting messages from an originating party to a receiving mobile station, and specifically to transmitting short message service (SMS) messages from an originating party to a receiving mobile station in a mobile communication system. 
   DESCRIPTION OF RELATED ART 
   Radiocommunication systems, such as cellular systems, support a plurality of different communication services. The most commonly recognized and widely used communication service relates to handling voice communications to and from the mobile stations of cellular subscribers. Cellular systems may further support e.g. asynchronous data communications, facsimile communications and short message service (SMS). The short message service (SMS) provides for the transmission of messages having up to a limited number of alphanumeric characters to be sent to a subscriber at his or her remote unit. 
   When sending SMS messages to and from a mobile station, a message center, which stores and forwards the SMS messages, is used. It should be noted that SMS messages can be sent from a computer connected to the Internet. Further an e-mail (electronic mail) can be sent to a mobile station, but then it is converted to an SMS message. 
   When transmitting an SMS message to a receiving mobile station (MS), radio base stations (RBSs), and mobile switching centers (MSCs), are also involved beside the message centers. The communication between the MSCs and message centers is handled by different network interfaces such as TIA/EIA-41. The communication between MSC/RBS and mobile stations is handled by different air interfaces such as TIA/EIA-136. For a cellular system conforming to TIA/EIA-136, the SMS message is transmitted between an MSC and a mobile station on a Digital Control Channel (DCCH) or Digital Traffic Channel (DTC) inside a layer 3 R-DATA message. The SMS message is encapsulated into a User Data Unit of a SMS SUBMIT message from an originating party transmitting the message to the MSC and message center. The SMS message is encapsulated into a User Data Unit of a SMS DELIVER message when submitted to the receiving mobile station, from the corresponding message center and MSC of the receiving mobile station. 
   The sender of an SMS message could today specify a validity period of the message. This information is used by the message center to determine for how long the message center should continue to try and forward the message to the receiving mobile station, e.g. if the receiving mobile station is switched off. 
   It is possible however that despite the message center managed to send a specific message within the validity period, the validity period of the message expires while the message is in the receiving mobile station memory before the receiver reads it. 
   SUMMARY OF THE INVENTION 
   The problem dealt with by the present invention is providing a more flexible processing of messages at a receiving mobile station. 
   One exemplary scenario is that a message that has been delivered to the receiving mobile station becomes overdue and still remains in the receiver&#39;s mobile station memory. For someone that receives several messages a day, having useless messages stored in his/her mobile station is inconvenient. It might result in that some important messages in the memory needs to be erased due to lack of space in the memory when a new message is received or that the new message is never saved. Therefore, important messages may never be saved or older interesting messages may be deleted before they have been read. 
   Briefly, the present invention solves said problem by transmitting both a message and a validity period associated with the message from the message center to the receiving mobile station. 
   By transmitting both a message and a validity period associated with the message, where the validity period is specified by the sender of the message, the receiving mobile station can use the validity period information when making decisions on how to process the received message. 
   An object of the invention is to enable a more flexible way of processing messages at a receiving mobile station. 
   Another object of the invention is to offer the receiver of a message a choice of determining how overdue messages should be processed. 
   An advantage of the present invention is enabling more flexible processing of messages at a receiving mobile station. 
   A further advantage of the present invention is that the receiver of a message has the choice of determining how overdue messages should be processed, thereby memory space in the mobile station could be used for more important messages. 
   Another advantage of the present invention is the possibility to use the validity period in a second memory, which could be an external memory from the mobile station such as e.g. a digital calendar. Functions can be included in the calendar as to sort messages after their validity period or to make the user of the calendar aware of an important message before the validity period of the message has expired. 
   Still an advantage is that the invention makes it possible for the message center to transmit the messages regardless of the contents in the field validity period. Instead of as today when the message center is deleting all overdue messages in the message center according to the validity period. Then the user of the receiving mobile station is increasing his/her control of what to do with his/her messages. It can be optional of course to let the message center delete overdue messages according to the validity period or to transmit regardless, still the messages transmitted in time to the mobile station can be processed in accordance with the preferences set by the user. 
   Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings and claims. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram illustrating a mobile telecommunication system including two mobile stations. 
       FIG. 2  is a block diagram illustrating layer 2 subchannels of the digital control channel DCCH and the digital traffic channel DTC. 
       FIG. 3  is a signal diagram illustrating a message flow from a sending mobile station to a receiving mobile station. 
       FIG. 4  is a schematic representation illustrating a transmission protocol when sending a SMS DELIVER message according to the invention. 
       FIG. 5  is a flow chart illustrating a message management solution dependent on a validity period according to the invention. 
       FIG. 6  is a block diagram illustrating two different embodiments of mobile stations according to the invention. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1  shows part of a mobile communication system  10 , including a cellular network and mobile stations, which apart from the normal speech and data communication is capable of transmission of SMS (short message service) messages. In the network according to  FIG. 1  there are two mobile switching centers (MSCs)  131  and  132 , each MSC is connected to a corresponding radio base station (RBS)  121  and  122 . A sending mobile station  101  intends to transmit a message to a receiving mobile station  102 , via the respective MSCs  131  and  132 . For this purpose, there are also in the system two message centers  141  and  142  corresponding to the MSCs  131  and  132 , in which messages are stored before a message is delivered to a recipient, e.g. the receiving mobile station  102 . 
   In general a network, such as a cellular network conforming to the TIA/EIA-136 and TIA/EIA-41 specification, is composed of a plurality of areas, each area being served by an MSC having an integrated visitor location register (VLR), see MSC/VLR  131  and  132  in  FIG. 1 . The MSC/VLR areas, in turn, include a plurality of location areas (LAs), which are defined as a part of a given MSC/VLR area in which a mobile station may move freely without having to send update location information to the MSC/VLR that controls the location area. Each location area is divided into a number of cells. 
   The RBS is the physical equipment, illustrated for simplicity as a radio tower  121  and  122  in  FIG. 1 , that provides radio coverage to the cell it is serving. 
   The VLR is a database containing information about all of the mobile stations currently located within the MSC/VLR area. If a mobile station roams into a new MSC/VLR area, the VLR connected to that MSC will request data about that mobile station from the home location register (HLR) database  150 , simultaneously informing the HLR  150  about the current location of the mobile station. Accordingly, if the user of the mobile station then wants to make a call, the local VLR will have the requisite identification information without having to reinterrogate the HLR  150 . In the aforedescribed manner, the VLR and HLR  150  databases, respectively, contain various subscriber informations associated with a given mobile station. 
   The HLR  150  maintains all subscriber information, e.g., user profiles, current location information, international mobile subscriber identity (IMSI) numbers, and other administrative information. It may be co-located with a given MSC, integrated with the MSC, or alternatively service multiple MSCs, the latter of which is illustrated in  FIG. 1 . 
     FIG. 2  is an overview of the layer 2 subchannels of the Digital Control Channel (DCCH) and Digital Traffic Channel (DTC) used in the present system and also for the SMS service as shown in  FIG. 1 . 
   The layer 2 functionality supported in TIA/EIA-136 reflects the operational requirements of the subchannels that make up the DCCH and the DTC. As a result of the differences in subchannel requirements, distinct layer 2 protocols have been specified for the major subchannel groupings as shown in  FIG. 2 . 
   The SPACH logical channel in DCCH is used to broadcast information to specific mobile stations regarding SMS Point-to-Point (SMSCH), paging (PCH) and to provide an access response channel (ARCH). 
   On the DTC, the logical channels that are used for SMS transport can be either the FACCH (Fast Associated Control Channel) or the SACCH (Slow Associated Control Channel). 
   A teleservice message, such as a SMS DELIVER or SMS SUBMIT message including a SMS message is delivered across the TIA/EIA-136 air interface on a DCCH or DTC inside a layer 3 R-DATA message, and across the TIA/EIA-41 network interface inside a layer 3 Short Message Delivery Point-to-Point SMDPP Invoke message (see  FIG. 3 ). The delivery of the layer 3 message may be acknowledged by the destination in a TIA/EIA-136 R-DATA ACCEPT or R-DATA REJECT message and a TIA/EIA-41 SMDPP Return Result message (see  FIG. 3 ). 
   In describing how an SMS message is sent from a sending mobile station  101  to a receiving mobile station  102  (in  FIG. 1 ), sending mobile station  101  first establishes a connection to the network (serving MSC/VLR  131 ), via an allocated digital control channel (DCCH. However, it should be noted that if sending mobile station  101  is in busy mode (in use), a connection already exists and the SMS message will be transmitted on the digital traffic channel (DTC) already in use for the existing call. It is also possible to set up a DTC specifically just to send and SMS. MSC/VLR  131  corresponding to the sending mobile station  101 , transmits the message to the sending mobile station&#39;s message center  141 . Thereafter, this message center  141  sends the message to the receiving mobile station&#39;s message center  142 . Then the receiving mobile&#39;s message center  142  asks the HLR for routing information regarding the receiving mobile station  102 . The HLR returns routing information to the receiving mobile&#39;s message center  142 , which then routes the message to the MSC/VLR  132 . The mobile station  102  is paged in that MSC/VLR-area, a connection is set-up between the network and the mobile station  102 , and the message is sent from the network to the mobile station  102 . 
   As a person skilled in the art appreciates, a single message center  141  or  142 , in  FIG. 1 , may serve both sending and receiving mobile stations  101  and  102 , as long as the mobile stations belong to the same message center. It is in no way limited to be different message centers  141  or  142  for different mobile stations  101  and  102 , as described in the section above. 
   The MSC provides the interworking between the message center and the mobile station by translating between the TIA/EIA-136 and TIA/EIA-41 protocols. 
   If the delivery was unsuccessful, e.g. because the receiving mobile station  102  was switched off, a messages waiting service within the message center  142  can optionally provide the HLR and the serving MSC/VLR  132  with the information that there is a message in the message center  142  waiting to be delivered to the receiving mobile station  102 . Once the receiving mobile station  102  becomes available for receipt of the SMS message, the HLR  150  informs the message center  142  and the SMS message is sent again. 
   An example message flow for SMS sent from one mobile station to another mobile station is illustrated in  FIG. 3 . The SMS message from sending mobile station  101  is encapsulated into the User Data Unit of the SMS SUBMIT message. The SMS SUBMIT message is delivered to the cellular network in an R-DATA message on either the DCCH or the DTC in  FIG. 2 . The R-DATA message, in  FIG. 4 , is translated into an SMDPP Invoke message by the MSC  131  serving sending mobile station  101  and delivered to the message center  141  serving sending mobile station  101 . The message center  141  serving sending mobile station  101  sends an acknowledgement in the form of an SMDPP Return Result message to the MSC  131 . The MSC  131  in turn sends out an R-DATA ACCEPT message to the sending mobile station  101  to indicate that the message has been received by the MSC  131 . The message center  141  serving sending mobile station  101  routes the SMS message to the message center  142  in an SMDPP Invoke message. The message center  142  acknowledges the received SMDPP Invoke message with a SMDPP Return Result message to the message center  141  serving sending mobile station  101 . An SMDPP Invoke message containing the SMS message for receiving mobile station  102  in an SMS DELIVER message is sent to an MSC  132  serving receiving mobile station  102  by the message center  142 . The MSC  132  then translates the SMDPP Invoke message into a R-DATA message and sends it to receiving mobile station  102  which in turn acknowledges the receipt of the R-DATA message with an R-DATA ACCEPT. The MSC  132  then sends an SMDPP Return Result message to the message center  142  as an acknowledgement of the SMS message delivery to receiving mobile station  102 . This step completes the routing of the SMS message from mobile station  101  to mobile station  102  through the R-DATA and SMDPP Invoke messages. 
   The sender of a SMS message can today associate the message with a validity period  610  (see  FIG. 6 ) that in that case will be transferred in a validity period field  610  in the SMS SUBMIT message to the message center  141 / 142 . In the message center  142  the SMS message will be deleted if the message is not delivered within the validity period  610  to the receiving mobile station  102 . The reason why a SMS message may not be delivered in time could e.g., be that the receiving mobile station  102  is turned off. 
   One scenario is that a message  611  (see  FIG. 6 ) that has been delivered to the receiving mobile station  102  becomes overdue and still remains in the receiver&#39;s mobile station first memory  601 . For someone that receives several messages a day, having useless messages stored in his/her mobile station  102  is inconvenient. It might result in that some important messages in the first memory  601  needs to be erased due to lack of space in memory when a new message is received or that the new message is never saved. Therefore, important messages may never be saved or older interesting messages may be deleted before they have been read. 
   The present invention enables a more flexible way of processing a message at a receiving mobile station  102 . In order to properly manage overdue messages, it is important to determine when they are overdue. This is possible if the validity period  610 , set by the sender  101  and used in the message center  141 / 142 , is passed to the receiving mobile station  102 . 
   With a validity period field  401  included in the SMS DELIVER message together with SMS message (see  FIG. 4 ), the validity period  610  information can be accessed in the receiving mobile station  102  and the user of the receiving mobile station  102  can use the information to decide if messages are overdue, and take actions on overdue messages. The user of the mobile station  102  can choose for example to delete overdue messages or to keep them in or forward them to a second memory  602 / 603 . The messages  611  may be time specific, but the user of a mobile station  102  may anyway choose to keep a message  611  instead of deleting it or he/she may choose to delete a message  611  after a grace period. The user could further choose e.g. whether messages  611  should be conditionally erased to allow for the reception of higher priority messages or whether they should be erased, as soon as their validity period  610  is up. Another choice could be to forward the message  611  to a digital calendar  620  or another kind of storage  602 / 603  depending on the validity period  610 . 
   According to one exemplary embodiment of the invention in a method for transmitting a message in a mobile communication system  10  from a originating party  101  to a receiving mobile station  102  the message  611  is first transmitted from the originating party  101  to a message center  141 / 142  where it is stored. Further, both the message  611  and associated validity period  610 , are transmitted from the message center  141 / 142  to the receiving mobile station  102 , and associated validity period  610  is being used in the receiving mobile station  102 . 
   In this exemplary embodiment of a method according to the invention, the field validity period  610  in the SMS SUBMIT message will correspond to a new field validity period  401  of the SMS DELIVER message when the SMS message is transferred from the message center  141 / 142  to the receiving mobile station  102 . Included in the SMS DELIVER message is also other fields of information elements (such as Message Type Indicator, Message Reference etc., see  FIG. 4 ) plus the SMS message  611  included in the User Data Unit  402  (see TIA/EIA-136). The receiver can choose to deal with SMS messages that are forwarded to the receiving mobile station  102  in his/her way by using the validity period  610  sent in the validity period field  401 . 
   The message center  141 / 142  is today deleting all SMS messages in the message center, which according to the validity period  610  are overdue. According to one alternative embodiment of the invention the SMS messages that become overdue when in the message center may instead of being deleted be transmitted to their destination regardless of their associated validity periods. This implies the choice of how to process the message is totally up to the receiver of the message, if he/she likes to use the information in the validity period field  610  or not. It can of course be optional to let the message center  141 / 142  delete messages that are overdue according to the validity period  610  or to transmit them regardless. If they are overdue or not the messages transmitted in time to the receiving mobile station  102  can still be processed, in accordance with the preferences set by the user of the receiving mobile station  102 . 
   In the future it may be possible to include a validity period  610  also in SMS messages  611  originating from a WEB-page on the Internet or in e-mails converted to SMS messages. 
   The validity period  610  is provided in the validity period field  401  in either offset or integer form. In the first case, the validity period field  401  provides the length of the validity period  610 , counted from when the SMS SUBMIT message is received by the message center  141 / 142 . In the second case, the validity period  610  provides the absolute date and/or time of the validity period  610  termination. A Validity Period Format field indicates the format used to code the validity period  610 . 
   How many alphanumeric characters that are allowed in a short message service (SMS) is limited by the message center that may have different maximum message length capability. The maximum message length is dependent on the implementation and can also be set by the system operators to optimize the system performance. 
     FIG. 4  illustrates generally the transmission protocol when sending R-DATA message according to the TIA/EIA-136 standard and how an SMS DELIVER message is created and transmitted as part of an R-DATA Unit  406  which in turn is part of an R-DATA message. The format of the R-DATA message is generally described in the TIA/EIA-136-123B 5.3.11. 
   The R-DATA Unit  406  comprises a Length Indicator  403 , a Higher Layer Protocol Identifier  404  and a Higher Layer Protocol Data Unit  405 . This Data Unit  405  includes the SMS DELIVER message. The SMS DELIVER message comprises a number of information elements including an User Data Unit field  402 , containing the SMS message  611 , being transmitted, a new Validity Period field  401 , containing a validity period  610  associated with said SMS message  611 . 
     FIG. 5  shows a flow chart of how an SMS message  611  and an associated validity period  610  are received and manipulated in the receiving mobile station in accordance with the receiver&#39;s preferences. 
   Once the user of the receiving mobile station  102  turns on  501  the receiving mobile station  102  he/she might enter preferences  502  such as whether a received message  611  should be stored in a first memory  601  until the associated validity period has expired, whether the user of the receiving mobile station  102  should be notified when the associated validity period  610  of a message  611  in the first memory  601  expires, whether the received message and the associated validity period  610  should be transferred  604 / 605  to a second memory  602 / 603 , or deleted from the first memory  601  when the associated validity period  610  expires. The user of a receiving mobile station  102  might also specify whether a grace period should apply before the message is deleted from the first memory  601  and whether messages that are overdue (messages with an expired associated validity period  610 ) should be placed in a second memory  602  included in the receiving mobile station  102  or external  603  to the receiving mobile station  102 . 
   Thus, when a message arrives  503 , the message  611  and associated validity period  610  are stored  504  in a first memory  601  in the receiving mobile station  102 . The receiving mobile station  102  extracts the associated validity period  610  if there is one provided and initiates a time supervision for that message by for example setting  505  a timer  606  in accordance with the associated validity period  610 . When the timer expires (an alternative Yes at  506 ), the receiving mobile station  102  uses  507  the preferences set by the user of the receiving mobile  102  in order to determine whether for example the messages should be deleted  508  in first memory  601  or transferred  604 / 605  to a second memory  602 / 603  and deleted  508  from the first memory  601 . In addition the receiving mobile station  102  might provide the user with the status of transferred and deleted messages by displaying  510  a suitable icon on its screen  607 . The receiving mobile station  102  can include a notification function, which would notify the user of the receiving mobile station  102  when the message  611  with an associated validity period  610  expires. Alternatively the user of the receiving mobile station  102  could be notified some time before (set according to user preferences) the message expires. Depending on how much earlier the user wants to receive a notification. The receiving mobile station  102  should be able to provide a record of messages that have been erased comprising the sender&#39;s address, the validity period  610  and the degree of urgency. 
   Instead of using a timer  606  the current date and/or time could be registered when a new message  611  arrives at the receiving mobile station  102 . If the message  611  has an associated validity period  610 , said validity period is compared to the registered current date and time to find out if the validity period  610  has expired. 
   When the option is set by the user of the receiving mobile station  102  to store received new SMS messages  611  in a first memory  601  in the receiving mobile station  102 , it is first necessary to control if there is enough available memory in the first memory  601  in the receiving mobile station  102  before storing the new received message. In case of a shortage of available memory, validity periods of the earlier stored messages are checked, and if a message is overdue, the overdue message is deleted to make space for the newly arrived message (the user of the receiving mobile station may even get a choice of reading the message that is going to be deleted before it is deleted if so is the option). This means that not more messages are deleted than is needed to make space for the newly received message. It may happen that there are messages which are not overdue but their validity periods are closer in time to become overdue than the newly arrived message  611  and there are not enough available memory in the first memory  601  of the receiving mobile station for saving the newly arrived message  611 . At these moments there are different ways of processing the message such as always deleting the newly arrived message  611 , deleting a message having a validity period that will expire first, transfer the newly arrived message  611  or the message having a validity period that will expire first to a second memory  602 / 603  etc. The second memory  602 / 603  can be a separate second memory  602  inside the receiving mobile station or an external separate second memory  603 . Another solution is to frequently check the first memory  601  for overdue messages instead of each time a new message arrives. When a check is done in the first memory  601  for overdue messages, the associated validity period  610  is compared to the date and/or time when the check is executed. See further what is described above. 
   In  FIG. 6  is a block diagram illustrating two different mobile stations  102 / 620  comprising memories  601 / 602 / 603 , a timer means  606  and a display means  607 . In the receiving mobile station  102  is included at least one first memory  601 . There may also be a second memory  602 , which is separate from the first memory  601 . If the first memory  601  is full can according to preferences set by the user of the mobile station  102  the message  611  and associated validity period  610  be deleted from the first memory  601 , and/or moved  604  to the second memory  602  inside the same receiving mobile station  102 . The message  611  and associated validity period  610  can also be moved  605 ′ to a second memory  603  included in another device such as e.g. a digital calendar  620 . A receiving mobile station  102  can also include calendar functions. In one solution to a calendar function described in  FIG. 5 , is needed a timer means  606  in the receiving mobile station  102 . To display the messages  611  a display means  607  is included in the receiving mobile station  102 . 
   As a person skilled in the art appreciates, application of the invention is in no way limited to only radio communication systems conforming to the TIA/EIA-136 and TIA/EIA-41 specifications. The invention is on the contrary applicable in e.g. all systems which utilizes short messages services such as systems conforming to e.g., the GSM-, PDC-, IS-95-, UMTS- or DECT-specifications. 
   As will be recognized by those skilled in the art, the innovative concepts described in the present application can be modified and varied over a wide range of applications. Accordingly, the scope of patented subject matter should not be limited to any of the specific exemplary teachings discussed.