Enhanced method and apparatus for MT SM transmission for eDRX-enabled mobile terminals

Abstract

The present invention relates to a mobility management node and a method of the mobility management node for enabling the transmission of a mobile terminated (MT) short message (SM) to a mobile terminal. In a first aspect of the present invention, a method of a mobility management node for enabling the transmission of a mobile terminated MT short message SM to a mobile terminal currently in an extended idle mode discontinuous reception (eDRX) mode is provided. The method comprises: receiving an indication from a short message service gateway mobile switching center (SMS-GMSC) that the SM is to be transmitted; receiving a notification that the mobile terminal has exited the extended idle discontinuous reception (eDRX) mode before a paging occasion occurs; and in response to the notification, submitting a message to the SMS-GMSC indicating that the mobile terminal is available for transmission of the SM.

Description

Technical Field

[0001] The present invention relates to a mobility management node and a method of said mobility management node enabling the transmission of a Mobile Terminated (MT) Short Message (SM) to a mobile terminal.

[0002] The invention also relates to a computer program for causing a mobility management node to perform the method according to the invention, and a corresponding computer program product. Background Art

[0003] Short Message Service (SMS) provides a means of sending limited-size messages to and from mobile terminals in Third Generation Partnership Project (3GPP) communication systems such as Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS) and Evolved Packet System (EPS). The provision of SMS utilizes a service center that acts as a repository and forwarding center for short messages.

[0004] Messages sent from mobile terminals are transmitted from the terminal to the service center, while messages terminated by mobile terminals should be transmitted from the service center to the terminal. Short messages are usually entered into the service center by other mobile users and then sent to other mobile users or users on the fixed network. This process is described in detail in the technical specification 3GPP TS23.040.

[0005] Today, in order to extend the battery life of mobile terminals, a method known as discontinuous reception (DRX) is used, in which the mobile terminal, usually referred to as user equipment (UE), only occasionally monitors the Physical Downlink Control Channel (PDCCH) to check whether downlink data is available.

[0006] Recently introduced UE types such as Machine Type Communication (MTC) devices require very efficient power saving, which has led to the introduction of a mode known as Extended Idle Mode DRX (eDRX). That is, the UE and the network can negotiate over Non-Access Stratum (NAS) signaling to use extended idle mode DRX to reduce its power consumption while being available for mobile terminated data and / or network initiated procedures within a certain delay dependent on the DRX cycle value. An eDRX-enabled UE can only be reached by the network (i.e., by network paging) during its Paging Transmission Window (PTW), and during this window, the UE uses normal DRX.

[0007] The delivery of Mobile Terminated (MT) Short Message (SM) messages from a Short Message Service Center (SMSC) to a Mobility Management Entity (MME) is described in “MT SMS procedures for UEs in extended idle mode DRX (MT SMS procedures for UEs in extended idle mode DRX, C4-152115, 3GPP TSG CT4 71st Meeting, Anaheim, USA; November 16-20, 2015)”.

[0008] Reference Figure 1 Timing diagram in .

[0009] 1. The SMSC submits a Send-Routing-Info-for-SM-Request (SRR) command to the Home Subscriber Server (HSS) to retrieve the address of the node serving the UE.

[0010] 2. The HSS responds accordingly by submitting a Send-Routing-Info-for-SM-Answer (SRA) message indicating the address of the serving MME.

[0011] 3. SMSC sends MT-Forward-Short-Message-Request (TFR) to the serving MME. SMSC indicates the maximum retransmission time (e.g. 5 to 10 minutes) in TFR, which indicates how long SMSC is prepared to store SM if SM cannot be transmitted immediately because UE is in extended idle mode DRX.

[0012] 4. If the UE is reachable within the maximum retransmission time provided in the TFR, the MME immediately sends an MT-Forward-Short-Message-Request-Answer (TFA) in step 4a, which indicates the requested retransmission time, i.e., the time when the SM should be retransmitted by the SMSC. The MME also pages the UE in 4b.

[0013] At this stage, the SMSC will not send a Report-SM-Delivery-Status-Request (RDR) to the HSS indicating that the SM delivery has failed. Therefore, the HSS will not reply with a Report-SM-Delivery-Status-Answer (RDA) message, nor will it store the service center address in its message waiting data (MWD).

[0014] 5. At the point in time when the signaling connection is established between the UE and the MME, the UE responds to the paging.

[0015] At this stage, the MME does not send a Notify-Request (NOR) to the HSS to notify that the UE has become reachable.

[0016] 6. The SMSC retransmits the SM at the requested retransmission time indicated in the TFA (the maximum retransmission time is not included in this second transmission of the TFR).

[0017] The solution in "MT SMS procedures for UEs in extended idle mode DRX" is described to present the following advantages:

[0018] a. MT SM of a UE in eDRX does not cause any additional HSS signaling.

[0019] b. There is no problem synchronizing messages received at the HSS within a short eDRX period (eg, up to 20 seconds).

[0020] c. If this procedure is used, a Single-attempt-delivery SM can be sent to the UE (no need to use MWD for the Single-attempt-delivery SM as specified previously).

[0021] The solution in "MT SMS procedures for UEs in extended idle mode DRX" is further described to present the following disadvantages:

[0022] a. Trigger SM retransmission when it is uncertain whether the UE is actually reachable (for example, the UE may have been detached, the UE may be in a tunnel, the eDRX period may have been renegotiated, etc.).

[0023] b. Greater impact on SMSC (buffering of MT-SM is prolonged, e.g., up to 5 to 10 minutes).

[0024] c. The Mobile Station Not Reachable Flag (MNRF) flag is not set in the HSS, therefore, subsequent MT SMs sent from different SMSCs to the same UE will trigger a new MT Forward SM Request to the MME for the unreachable UE.

[0025] d. Introduce another method to transmit MT SMS to UE using extended idle mode DRX.

[0026] The applicant has recognized other drawbacks of this solution, as will be seen in reference Figure 2 discussed.

[0027] like Figure 1 As shown, the SMSC submits a TFR to the currently serving MME (MME1) to indicate that the SM will be submitted to the UE. The TFR includes a maximum retransmission time, which indicates how long the SMSC is prepared to store the SM when the SM cannot be delivered immediately because the UE is in eDRX.

[0028] MME1 responds accordingly via TFA, which indicates the requested retransmission time at which the SMSC should retransmit the SM, and then pages the UE when the next paging opportunity occurs (occurs just before the start of the next paging transmission window, i.e., just before the indicated requested retransmission time), so that when the UE wakes up from its eDRX cycle at the requested retransmission time, the SM can be transmitted from the SMSC to the UE via MME1 in a timely manner.

[0029] Now, in this specific example MME1, the first problem arises if the UE wakes up from its eDRX cycle before being paged by the serving mobility management node, thereby exiting eDRX mode (e.g. due to a UE service request to send data), and accordingly initiates NAS signaling to its current serving mobility management node (e.g. MME or serving GPRS (General Packet Radio Service) Support Node (SGSN)).

[0030] For Long Term Evolution / Evolved Universal Terrestrial Access Network (LTE / E-UTRAN) access, NAS signaling is used to convey non-wireless signaling between the UE and the MME. For example, a NAS request can be a Routing Area Update (RAU) request to update the UE location within the network. When the UE detects that it has entered a new routing area, the UE initiates a RAU and will therefore contact the core network (the current serving SGSN or a new SGSN).

[0031] Thus, the first problem can be illustrated as occurring in the case of an intra-SGSN RAU request, i.e., when the UE enters a new routing area but is still in the serving SGSN (as indicated by Figure 2 When the SMSC attempts to submit the SM to the UE at the requested retransmission time specified by the TFA, there is a risk that the UE will enter eDRX mode again, resulting in failure of the scheduled MT-SMS delivery. When the UE resides in the UTRAN, the eDRX cycle will be restarted at each routing area update procedure.

[0032] When the UE resides in E-UTRAN and GSM, the paging occasion scheme can be maintained if the serving MME or SGSN maintains the eDRX cycle regardless of whether the UE requests a change in the eDRX cycle at the TAU / RAU. In this case, the problem is less troublesome, but MT-SMS will still be unnecessarily delayed until the next scheduled paging occasion, additional signaling to the UE is required, and the UE power consumption is increased, which should actually be avoided.

[0033] In addition, before the UE responds to the paging message from the network, if the UE initiates a NAS request to another mobility management node, thereby communicating between the two management nodes (the other node is represented by the MME) called an inter-MME TAU request. Figure 2 If the idle mode mobility process is implemented between the first mobility management node and the second mobility management node, the second problem occurs. That is, the paging message has not been sent by the first mobility management node because the paging window has not appeared yet.

[0034] This problem occurs, for example, if the UE initiates an MME TAU request after MME1 reports a requested retransmission time to SMSC (which indicates the next paging occasion based on the eDRX cycle), but before the actual paging occasion occurs.

[0035] In this case, the SMSC will transmit the MT-SMS to the wrong MME (ie, MME1) at the requested retransmission time specified by the TFA. Summary of the invention

[0036] It is an object of the present invention to solve or at least partially alleviate at least one of these problems in the art and therefore to provide an improved method of facilitating the transmission of short messages to an eDRX mode enabled mobile terminal.

[0037] In a first aspect of the invention, this object is achieved by a method of enabling a mobility management node to deliver a mobile terminating MT short message SM to a mobile terminal currently in an eDRX mode. The method comprises: receiving an indication from a Short Message Service Gateway Mobile Switching Center (SMS-GMSC) that the SM is to be delivered; receiving a notification that the mobile terminal has exited the eDRX mode before a paging occasion occurs; and in response to the notification, submitting a message to the SMS-GMSC indicating that the mobile terminal is available for delivery of the SM.

[0038] In a second aspect of the present invention, this object is achieved by a mobility management node configured to enable the transmission of an MT SM to a mobile terminal currently in an extended eDRX mode, and the mobility management node includes a processing unit and a memory, the memory containing instructions executable by the processing unit, whereby the mobility management node is operable to: receive an indication from an SMS-GMSC that the SM is to be transmitted; receive a notification that the mobile terminal has exited the eDRX mode before a paging occasion occurs; and in response to the notification, submit a message to the SMS-GMSC indicating that the mobile terminal is available for transmission of the SM.

[0039] In a third aspect of the present invention, this object is achieved by a method for enabling a mobility management node to transmit an MT SM to a mobile terminal currently in eDRX mode, the method comprising: receiving a notification that the mobile terminal has exited the eDRX mode before a paging occasion occurs; submitting a context request to another mobility management node that serves the mobile terminal before the notification is received; receiving a context response including an indication that the SM is to be transmitted from the other mobility management node; and receiving the SM for transmission to the mobile terminal from the SMS-GMSC.

[0040] In a fourth aspect of the present invention, this object is achieved by a mobility management node configured to enable the transmission of an MT SM to a mobile terminal currently in an eDRX mode, and the mobility management node includes a processing unit and a memory, the memory containing instructions executable by the processing unit, whereby the mobility management node is operable to: receive a notification that the mobile terminal has exited the eDRX mode before a paging occasion occurs; submit a context request to another mobility management node that serves the mobile terminal before the notification is received; receive a context response including an indication that the SM is to be transmitted from the other mobility management node; and receive the SM from the SMS-GMSC for transmission to the mobile terminal.

[0041] In one embodiment, the message is submitted directly to the SMS-GMSC.

[0042] In another embodiment, the message is submitted to the SMS-GMSC via a Home Subscription Server (50) HSS.

[0043] In one embodiment, the message submitted to the SMS-GMSC via the HSS further includes an instruction instructing the HSS to provide a destination address of the mobility management to the SMS-GMSC.

[0044] In yet another embodiment, the notification is a non-access stratum (NAS) request received from the mobile terminal.

[0045] In another embodiment, the notification is a context request received from a service mobility management node of the mobile terminal, and the method further comprises: submitting a context response including an indication that the SM is to be transmitted to the service mobility management node; and receiving a context confirmation including a destination address of the service mobility management node for SM transmission from the service mobility management node, wherein the submitted message further comprises the destination address of the service mobility management node.

[0046] In another embodiment, the notification is a context request received from a serving mobility management node of the mobile terminal, the message being submitted to the SMS-GSMC in a context response via the serving mobility management node and further comprising a destination address of the SMS-GSMC.

[0047] In another embodiment, receiving an indication from an SMS-GMSC that the SM is to be transmitted includes: receiving an indication of a maximum retransmission time and a capability indication, the maximum retransmission time specifying how long the SMS-GMSC will store the SM if the SM cannot be transmitted immediately, the capability indication indicating whether the SMS-GMSC supports receiving subsequent notifications of the availability of the mobile terminal for transmitting the SM, and the method further includes: submitting an indication including a requested retransmission time and a capability confirmation to the SMS-GMSC, the requested retransmission time indicating at which point in time the SMS-GMSC should retransmit the SM, and the capability confirmation indicating that the mobility management node supports the subsequent notifications of the availability of the mobile terminal for transmitting the SM.

[0048] In a further embodiment, the submitted message further indicates a time period defining a time until said mobile terminal enters said eDRX mode again.

[0049] In general, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless otherwise explicitly defined herein. All references to "a / an / the element, device, component, part, step, etc." will be publicly interpreted as referring to at least one instance of the element, device, component, part, step, etc., unless otherwise explicitly stated. Unless explicitly stated, the steps of any method disclosed herein do not have to be performed in the exact order disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0051] Figure 1 is a prior art timing diagram showing MT SM transfer from SMC to MME;

[0052] Figure 2 is shown with Figure 1 Timing diagram of issues related to the MT SM transmission process;

[0053] Figure 3 An embodiment of the method of the present invention is shown;

[0054] Figure 4 Another embodiment of the method of the present invention is shown;

[0055] Figure 5 Another embodiment of the method of the present invention is shown;

[0056] Figure 6 Another embodiment of the method of the present invention is shown;

[0057] Figure 7 A still further embodiment of the method of the present invention is shown;

[0058] Figure 8 A further embodiment of the method of the present invention is shown;

[0059] Fig. 9 Another embodiment of the method of the present invention is shown;

[0060] Fig.10 Another embodiment of the method of the present invention is shown;

[0061] Fig.11 An embodiment of a mobility management node of the present invention is shown; and

[0062] Fig.12 A further embodiment of the mobility management node of the present invention is shown. DETAILED DESCRIPTION

[0063] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, which illustrate certain embodiments of the present invention. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete and will fully convey the scope of the present invention to those skilled in the art. Throughout the specification, the same numerals refer to the same elements.

[0064] Figure 1A timing diagram illustrating the MT SM transmission from SMSC to MME disclosed in the previous introduction "MT SMS procedures for UEs in extended idlemode DRX" is shown.

[0065] Figure 2 shows the previously introduced Figure 1 The SMSC will be referred to as the Short Message Service Gateway Mobile Switching Center (SMS-GMSC) hereinafter.

[0066] In short, the first problem occurs if the UE 10 wakes up from the eDRX cycle, i.e. exits the eDRX mode it resides in, before the next paging occasion occurs. The SMS-GMSC 40 has already scheduled SM delivery for the next paging occasion and therefore misses the opportunity to deliver the SM to the UE 10 exiting the eDRX mode via the MME1 / SGSN1 20; once the next paging occasion occurs, there is a risk that the UE 10 will re-enter the eDRX mode, resulting in another SM delivery failure and the process having to be repeated.

[0067] In addition, a second problem occurs if the UE 10 exits the eDRX mode in which it resides before the next paging occasion occurs, which in this case refers to performing, for example, an inter-MME TAU. In this case, when the SMS-GMSC 40 is scheduled for SM delivery for the next paging occasion, the SMS-GMSC 40 does not deliver the SM to the MME2 / SGSN2 30, but instead delivers the SM to the MME1 / SGSN1 20 which is no longer the serving MME.

[0068] In the following, MME1 / SGSN1 and MME2 / SGSN2 will be referred to as MME1 and MME2, respectively. However, it should be noted that they embody the mobility management nodes of both UTRAN and E-UTRAN.

[0069] Figure 3 One embodiment of the method of the present invention performed at the MME1 20 to enable the transfer of the MT SM from the SMS-GMSC 40 to the UE 10 is shown.

[0070] In a first step S101, MME1 20 receives an indication from SMS-GMSC 40 that a SM is to be delivered to UE 10 currently in eDRX mode. Now, if UE 10 exits eDRX mode before a paging occasion occurs, e.g. as a result of a NAS request or a general service request for intra-MME TAU, intra-SGSN RAU, etc., then MME1 20 will receive a notification accordingly in a second step S102.

[0071] In a third step S103, in response to the indication received in step S102, MME1 20 submits a message to SMS-GMSC 40 indicating that UE 10 is available to transmit SIM immediately. As a result, SMS-GMSC will advantageously not miss the opportunity to transmit SIM to UE 10 not currently in eDRX mode via MME 120 in step S104.

[0072] In an alternative embodiment, the message is not submitted directly to the SMS-GMSC 40, but is sent via the HSS ( Figure 3 In such an embodiment, the message submitted to the SMS-GMSC 40 via the HSS further includes an instruction instructing the HSS to provide the destination address of the MME1 20 (known to the HSS) to the SMS-GMSC 40 so that the SMS-GSMC 40 can transmit the SIM to the UE 10 via the MME120.

[0073] Figure 4 One embodiment of the method of the invention enabling the transfer of a MT SM from an SMS-GMSC 40 to a UE 10 is shown.

[0074] In a first step S101, MME1 20 receives an indication from SMS-GMSC 40 that a SIM is to be delivered to a UE 10 currently in eDRX mode. Now, if the UE 10 exits eDRX mode before a paging occasion occurs, for example as a result of a NAS request or a general service request for TAU, RAU, etc. sent to MME2 30 at step S102a, the other MME1 20 will receive notification accordingly. However, unlike reference 1 Figure 3 In contrast to the described embodiment, the notification is in this case not received from the UE 10 but from the MME 2 (now the serving MME) in the form of a context request in step S102b.

[0075] As a result, MME1 20 submits a context response at step S102c to be received by MME2 30 and including an indication that the SM is to be transferred. In response thereto, MME1 20 receives a context acknowledgement at step S102d sent by MME2 and including the destination address of the new serving MME (ie, MME2 30) for subsequent SM transfer.

[0076] At step S103, MME1 20 submits a message to SMS-GMSC 40 indicating that UE 10 is available to immediately transmit SM in response to the notification received at step S102b, which message further includes the destination address of MME2 30 as the serving MME in this embodiment.

[0077] As a result, the SMS-GMSC 40 will advantageously transmit the SM to the correct MME, namely MME2 30, at step S105, and further to the UE 10 which is not currently in eDRX mode.

[0078] Reference again Figure 4 In an alternative embodiment, the notification that the UE 10 has exited the eDRX mode is again received in the form of a context request from the MME2 30 in step S102b. However, the message indicating that the SM can be immediately transmitted to the UE 10 is submitted to the SMS-GSMC 40 via the MME2 30 in step S103a in the context response of step S102c, and this message further includes the destination address of the SMS-GSMC 40 for the information of the MME2 30 in this embodiment.

[0079] Similar to reference Figure 4 In the embodiments discussed, it is contemplated that in one embodiment the message is not submitted directly to the SMS-GMSC 40, but rather is sent via the HSS ( Figure 4 In such an embodiment, the message submitted to the SMS-GMSC 40 via the HSS further includes an instruction instructing the HSS to provide the destination address of the MME2 30 to the SMS-GMSC 40 so that the SMS-GSMC 40 can transmit the SIM to the UE 10 via the correct MME (ie, MME2 30).

[0080] refer to Figure 3 and Figure 4 In one embodiment, it is contemplated that step S101 (wherein the MME 120 receives an indication from the SMS-GMSC 40 that an SIM is to be delivered to the UE 10 currently in the eDRX mode) is extended to include the following steps: Figure 5 Steps S101a and S101b.

[0081] Figure 5 Based on the previous reference Figure 3 The embodiments discussed are embodiments of the present invention performed at the MME1 20 that enable the transfer of the MT SM from the SMS-GMSC 40 to the UE 10 .

[0082] In a first step S101a, MME1 20 receives an indication from SMS-GMSC 40 that an SM is to be delivered to UE10 in the form of a TFR, the TFR including a maximum retransmission time indicating how long the SMS-GMSC 40 stores the SM if the SM cannot be delivered immediately; and MME1 20 further receives a capability indication indicating whether SMS-GMSC 40 supports receiving subsequent notifications of UE availability for delivering the SM.

[0083] Thereafter, in step S101b, since the UE 10 is currently in eDRX mode, the MME1 20 responds with a TFA indicating a requested retransmission time, i.e., the time when the SM should be retransmitted by the SMS-GMSC 40. The TFA further indicates whether the MME1 supports subsequent notification of UE availability for transmitting the SM when the UE 10 exits the eDRX mode.

[0084] As already described before, if the UE 10 exits the eDRX mode before a paging occasion occurs, for example as a result of a NAS request or a general service request for intra-MME TAU, intra-SGSN RAU, etc., the MME1 20 will receive a notification accordingly in the second step S102.

[0085] At step S103, in response to the indication received at step S102, MME1 20 submits a message to SMS-GMSC 40 indicating that UE 10 is available to immediately transmit SIM. As a result, SMS-GMSC will advantageously not miss the opportunity to transmit SIM to UE 10 not currently in eDRX mode via MME1 20 at step S104.

[0086] Optionally, for all embodiments of the invention, this message comprises a maximum UE availability time, ie a time period defining the time until the UE 10 enters eDRX mode again, thereby advantageously indicating a time window during which the UE 10 is available for SM transmissions.

[0087] from Figure 5 As can be seen in FIG. 1 , the submission in step S103 uses an existing message such as OFR or a new Diameter message. SMS-GMSC 40 accordingly uses an existing message such as OFA or a new Diameter message to confirm the message in step S104a.

[0088] The pending SM is transmitted by the SMS-GMSC 40 in a TFR in step S104, and the MME 1 accordingly confirms the transmission through a TFA in step S106.

[0089] Figure 6 Based on the previous reference Figure 4 The discussed embodiment is one embodiment of the present invention performed at the MME1 20 to enable the transfer of the MT SM from the SMS-GMSC 40 to the UE 10 .

[0090] In a first step S101a, MME1 20 receives an indication from SMS-GMSC 40 that an SM is to be delivered to UE10 in the form of a TFR, the TFR including a maximum retransmission time indicating how long the SMS-GMSC 40 stores the SM if the SM cannot be delivered immediately; and MME1 20 further receives a capability indication indicating whether the SMS-GMSC 40 supports receiving subsequent notifications of UE availability for delivering the SM.

[0091] Thereafter, in step S101b, since UE 10 is currently in eDRX mode, MME1 20 responds with TFA, which indicates a requested retransmission time, i.e., the time when the SM should be retransmitted by SMS-GMSC 40. TFA further indicates whether MME1 supports subsequent notification of UE availability for transmitting SM when UE 10 exits eDRX mode.

[0092] As already described before, if the UE 10 exits the eDRX mode before a paging occasion occurs, for example as a result of a NAS request or a general service request for intra-MME TAU, intra-SGSN RAU, etc., the MME1 20 will receive a notification accordingly in the second step S102.

[0093] In step S103b, in response to the indication received in step S102, MME1 20 submits a message indicating that UE 10 is available for immediate transmission of SM to SMS-GMSC 40 via HSS 50. This message may be submitted, for example, in the form of an Update Location Request (ULR) or a Notification Request (NOR), and includes instructions instructing HSS 50 to subsequently provide the destination address of MME1 20 to SMS-GMSC 40.

[0094] The HSS 50 accordingly responds at step S103c with an acknowledgement in the form of, for example, an Update Location Answer (ULA) or a Notification Answer (NOA), and at step S103d sends a message in an Alert-Service-Centre-Request (ALR) indicating the availability of the UE and the address of the MME1 20. The SMS-GMSC therefore sends an acknowledgement Alert-Service-Centre-Answer (ALA) to the HSS 50 at step S103e.

[0095] Optionally, the messages in S103b and S103d include a maximum UE availability time, ie a time period specifying the time until the UE 10 enters the eDRX mode again, thereby advantageously indicating a time window during which the UE 10 is available for SM transmission.

[0096] The pending SM is transmitted by SMS-GMSC 40 in TFR at step S104, and MME1 accordingly confirms the transmission using TFA at step S106. As a result, SMS-GMSC 40 will advantageously not miss the opportunity to transmit the SM via MME1 20 at step S104 to UE 10 that is not currently in eDRX mode.

[0097] Figure 7 Based on the previous reference Figure 4 The discussed embodiment is one embodiment of the present invention that enables the transfer of the MT SM from the SMS-GMSC 40 to the UE 10.

[0098] In a first step S101a, MME1 20 receives an indication from SMS-GMSC 40 that an SM is to be delivered to UE10 in the form of a TFR, the TFR including a maximum retransmission time indicating how long the SMS-GMSC 40 stores the SM if the SM cannot be delivered immediately; and MME1 20 further receives a capability indication indicating whether the SMS-GMSC 40 supports receiving subsequent notifications of UE availability for delivering the SM.

[0099] Thereafter, in step S101b, since UE 10 is currently in eDRX mode, MME1 20 responds with TFA, which indicates a requested retransmission time, i.e., the time when the SM should be retransmitted by SMS-GMSC 40. TFA further indicates whether MME1 supports subsequent notification of UE availability for transmitting SM when UE 10 exits eDRX mode.

[0100] If UE 10 exits eDRX mode before a paging occasion occurs, for example as a result of a NAS request for TAU, RAU or a general service request etc. sent to MME 230 at step S102a, MME1 20 will accordingly receive a notification from MME 230 (now the serving MME) in the form of a context request at step S102b.

[0101] As a result, MME1 20 submits a context response including an indication that the SM is to be delivered to MME2 30 at step S102c, which message in this embodiment further includes the destination address of the SMS-GSMC 40 for information of MME2 30. In response thereto, MME2 30 sends a context acknowledgement to MME1 20 at step S102d.

[0102] In step S103a, in response to the indication received in step S102c, MME2 30 submits a message indicating that UE 10 is available to immediately transmit SM to SMS-GMSC 40. As a result, SMS-GMSC 40 will advantageously transmit the SM to the correct MME, i.e., MME2 30, in step S105, and further to UE 10 that is not currently in eDRX mode.

[0103] Optionally, this message includes a maximum UE availability time, ie a time period specifying the time until the UE 10 enters eDRX mode again, thereby advantageously indicating a time window during which the UE 10 is available for SM transmissions.

[0104] from Figure 7 As can be seen in FIG. 1 , the submission in step S103 uses an existing message such as OFR or a new Diameter message. The SMS-GMSC 40 accordingly confirms the message in step S105a using an existing message such as OFA or a new Diameter message.

[0105] The pending SM is transmitted by the SMS-GMSC 40 in the TFR of step S105, and the MME2 30 accordingly confirms the transmission using the TFA in step S106a.

[0106] Figure 8 shows the same as the previous reference Figure 7 The discussed embodiment relates to an embodiment of the present invention that enables the transfer of a MT SM from the SMS-GMSC 40 to the UE 10.

[0107] However, in this particular embodiment, a message indicating that the UE is available for SM delivery is sent by the MME 230 to the SMS-GSMC 40 via the HSS 50 .

[0108] In a first step S101a, MME1 20 receives an indication from SMS-GMSC 40 that an SM is to be delivered to UE10 in the form of a TFR, the TFR including a maximum retransmission time indicating how long the SMS-GMSC 40 stores the SM if the SM cannot be delivered immediately; and MME1 20 further receives a capability indication indicating whether the SMS-GMSC 40 supports receiving subsequent notifications of UE availability for delivering the SM.

[0109] Thereafter, in step S101b, since UE 10 is currently in eDRX mode, MME1 20 responds with TFA, which indicates a requested retransmission time, i.e., the time when the SM should be retransmitted by SMS-GMSC 40. TFA further indicates whether MME1 supports subsequent notification of UE availability for transmitting SM when UE 10 exits eDRX mode.

[0110] If UE 10 exits eDRX mode before a paging occasion occurs, for example as a result of a NAS request for TAU, RAU or a general service request etc. sent to MME 230 at step S102a, MME1 20 will accordingly receive a notification from MME 230 (now the serving MME) in the form of a context request at step S102b.

[0111] As a result, MME1 20 submits a context response including an indication that the SM is to be delivered to MME2 30 at step S102c, which message in this embodiment further includes the destination address of the SMS-GSMC 40 for information of MME2 30. In response thereto, MME2 30 sends a context acknowledgement to MME1 20 at step S102d.

[0112] In step S103f, in response to the indication received in step S102c, MME2 30 submits a message indicating that UE 10 is available to immediately transmit SM to SMS-GMSC 40 via HSS 50. This message may be submitted in the form of a ULR or NOR, for example, and includes an instruction instructing HSS 50 to then provide the destination address of MME2 30 to SMS-GMSC 40.

[0113] The HSS 50 accordingly responds at step S103g with an acknowledgement in the form of, for example, a ULA or NOA, and sends at step S103h a message in the ALR indicating the UE availability and the address of the MME2 30. The SMS-GMSC 40 therefore sends an acknowledgement (ALA) to the HSS 50 at step S103i.

[0114] Optionally, the message in steps S103f and S103h comprises a maximum UE availability time, ie a time period defining the time until the UE 10 enters the eDRX mode again, thereby advantageously indicating a time window during which the UE 10 is available for SM transmissions.

[0115] The SMS-GMSC 40 will advantageously transmit the SM to the correct MME, namely MME2 30, at step S105, and further to the UE 10 which is not currently in eDRX mode, and MME2 30 accordingly confirms the transmission using TFA at step S106a.

[0116] Fig. 9 Based on the previous reference Figure 4 The discussed embodiment is one embodiment of the present invention that enables the transfer of the MT SM from the SMS-GMSC 40 to the UE 10.

[0117] In a first step S101a, MME1 20 receives an indication from SMS-GMSC 40 that a SIM is to be delivered to UE 10. Preferably, the indication takes the form of a TFR, the TFR including a maximum retransmission time indicating how long the SMS-GMSC 40 stores the SIM if the SIM cannot be delivered immediately. The indication may further include a capability indication indicating whether the SMS-GMSC 40 supports receiving subsequent notifications of the UE's availability for delivering the SIM.

[0118] Thereafter, in step S101b, since the UE 10 is currently in the eDRX mode, the MME1 20 preferably responds to the SMS-GMSC 40 with a TFA, which indicates a requested retransmission time, i.e., the time when the SM should be retransmitted by the SMS-GMSC 40. The TFA may further indicate whether the MME1 supports subsequent notification of UE availability for transmitting the SM when the UE 10 exits the eDRX mode.

[0119] If the UE 10 exits eDRX mode before a paging occasion occurs, for example as a result of a NAS request for TAU, RAU or a general service request etc. sent to MME230 at step S102a, other MME1 20 will accordingly receive a notification from MME2 30 (now the serving MME) in the form of a context request at step S102b.

[0120] As a result, MME1 20 submits a context response to MME2 30 at step S102c, the context response including an indication that the SM is to be received by MME2 30. In response thereto, MME2 30 sends a context acknowledgement including the destination address of MME2 30 to MME1 20 at step S102d.

[0121] At step S103, MME1 20 submits a message to SMS-GMSC 40 indicating that UE 10 is available to transmit SM immediately and including the destination address of MME2 30. As a result, SMS-GMSC 40 will advantageously transmit the SM to the correct MME, i.e., MME2 30, at step S104, and further to UE 10 that is not currently in eDRX mode.

[0122] Optionally, this message includes a maximum UE availability time, ie a time period specifying the time until the UE 10 enters eDRX mode again, thereby advantageously indicating a time window during which the UE 10 is available for SM transmissions.

[0123] from Fig. 9 As can be seen in FIG. 1 , the submission in step S103 uses an existing message such as OFR or a new Diameter message. The SMS-GMSC 40 accordingly uses an existing message such as OFA or a new Diameter message to confirm the message in step S104a.

[0124] The pending SM is transmitted by the SMS-GMSC 40 in a TFR in step S105, and the MME 1 accordingly confirms the transmission using a TFA in step S106a.

[0125] Fig.10 shows the same as the previous reference Fig. 9 The discussed embodiment relates to an embodiment of the present invention that enables the transfer of a MT SM from the SMS-GMSC 40 to the UE 10.

[0126] However, in this particular embodiment, a message indicating that the UE is available for SM delivery is sent by the MME 120 to the SMS-GSMC 40 via the HSS 50 .

[0127] In a first step S101a, MME1 20 receives an indication from SMS-GMSC 40 that an SM is to be delivered to UE10 in the form of a TFR, wherein the TFR includes a maximum retransmission time indicating how long the SMS-GMSC 40 stores the SM if the SM cannot be delivered immediately; and MME1 20 further receives a capability indication indicating whether the SMS-GMSC 40 supports receiving subsequent notifications of UE availability for delivering the SM.

[0128] Thereafter, in step S101b, since UE 10 is currently in eDRX mode, MME1 20 responds with TFA, which indicates a requested retransmission time, i.e., the time when the SM should be retransmitted by SMS-GMSC 40. TFA further indicates whether MME1 supports subsequent notification of UE availability for transmitting SM when UE 10 exits eDRX mode.

[0129] If UE 10 exits eDRX mode before a paging occasion occurs, for example as a result of a NAS request for TAU, RAU or a general service request etc. sent to MME 230 at step S102a, MME1 20 will accordingly receive a notification from MME 230 (now the serving MME) in the form of a context request at step S102b.

[0130] As a result, MME1 20 submits a context response including an indication that the SM is to be transferred to MME2 30 at step S102c, in response to which MME2 30 sends a context acknowledgement including the destination address of MME2 30 to MME1 20 at step S102d.

[0131] At step S103b, MME2 30 submits a message indicating that UE 10 is available to immediately transmit SM to SMS-GMSC 40 via HSS 50. This message may be submitted in the form of a ULR or NOR, for example, and includes instructions instructing HSS 50 to then provide the destination address of MME2 30 to SMS-GMSC 40.

[0132] The HSS 50 accordingly responds at step S103c with an acknowledgement in the form of, for example, a ULA or NOA, and sends at step S103h a message in the ALR indicating the UE availability and the address of the MME2 30. The SMS-GMSC 40 therefore sends an acknowledgement (ALA) to the HSS 50 at step S103e.

[0133] Optionally, the messages in steps S103b and S103c include a maximum UE availability time, ie a time period defining the time until the UE 10 enters the eDRX mode again, thereby advantageously indicating a time window during which the UE 10 is available for SM transmissions.

[0134] The SMS-GMSC 40 will advantageously transmit the SM to the correct MME, namely MME2 30, at step S105, and further to the UE 10 which is not currently in eDRX mode, and MME2 30 accordingly confirms the transmission using TFA at step S106a.

[0135] refer to Fig.11, the steps of the method performed by the mobility management node 20, 30 according to an embodiment of the present invention are actually performed by a processing unit 21, 31, which is embodied in the form of one or more microprocessors, which are arranged to execute a computer program 22, 32 downloaded to a suitable storage medium 23, 33 associated with the microprocessor, such as a random access memory (RAM), flash memory or hard drive. The processing unit 21, 31 is arranged to cause the computing device 20, 30 to perform a method according to an embodiment of the present invention when a suitable computer program 22, 32 including computer executable instructions is downloaded to the storage medium 23, 33 and executed by the processing unit 21, 31. The storage medium 23, 33 may also be a computer program product including the computer program 22, 32. Alternatively, the computer program 22, 32 may be transferred to the storage medium 23, 33 by means of a suitable computer program product, such as a digital versatile disc (DVD) or a memory stick. As a further alternative, the computer program 22, 32 may be downloaded to the storage medium 23, 33 via a network. Alternatively, the processing units 21 , 31 may be embodied in the form of a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a complex programmable logic device (CPLD), or the like.

[0136] Fig.12 A first mobility management node 20 configured to enable the delivery of an MT SM to a mobile terminal according to an embodiment of the present invention is shown. The mobility management node 20 comprises a receiving means 24 adapted to receive an indication from an SMS-GMSC that the SM is to be delivered; a receiving means 25 adapted to receive a notification that the mobile terminal has exited the eDRX mode before a paging occasion occurs; and a submitting means 26 adapted to submit, in response to the notification, a message indicating to the SMS-GMSC that the mobile terminal is available for delivery of the SM.

[0137] The devices 24 to 26 may include a communication interface for receiving and providing information, and may further include a local memory for storing data, and may (similar to the combination of Fig.11 The description given) is implemented by a processor embodied in the form of one or more microprocessors arranged to execute computer programs downloaded to a suitable storage medium (such as RAM, flash memory or hard drive) associated with the microprocessor.

[0138] Fig.12A second mobility management node 30 configured to enable transmission of an MT SM to a mobile terminal according to an embodiment of the present invention is shown. The mobility management node 30 comprises a receiving device 34 adapted to receive a notification that the mobile terminal has exited the eDRX mode before a paging occasion occurs; a submitting device 35 adapted to submit a context request to another mobility management node serving the mobile terminal before the notification is received; a receiving device 36 adapted to receive a context response from the other mobility management node including an indication that the SM is to be transmitted and a destination address of an SMS-GMSC transmitting the SM; and a submitting device 37 adapted to submit, in response to the context response, a message to the SMS-GMSC indicating that the mobile terminal is available for sending the SM.

[0139] The devices 34 to 37 may include a communication interface for receiving and providing information, and may further include a local memory for storing data, and may (similar to the combination of Fig.11 The description given) is implemented by a processor embodied in the form of one or more microprocessors arranged to execute computer programs downloaded to a suitable storage medium (such as RAM, flash memory or hard drive) associated with the microprocessor.

[0140] Some of the embodiments described above can be summarized in the following way:

[0141] The first embodiment relates to a method of a mobility management node enabling delivery of a Mobile Terminated (MT) Short Message (SM) to a mobile terminal currently in an extended idle mode discontinuous reception (eDRX) mode.

[0142] The method comprises:

[0143] receiving an indication from a Short Message Service Gateway Mobile Switching Center (SMS-GMSC) that the SM is to be delivered;

[0144] receiving a notification that the mobile terminal has exited the eDRX mode before a paging occasion occurs; and

[0145] In response to the notification, a message is submitted to the SMS-GMSC indicating that the mobile terminal is available for delivery of the SIM.

[0146] The message may be submitted directly to the SMS-GMSC.

[0147] The message may be submitted to the SMS-GMSC via a Home Subscription Server (HSS).

[0148] The message submitted to the SMS-GMSC via the HSS further includes an instruction instructing the HSS to provide a destination address of the mobility management to the SMS-GMSC.

[0149] The notification may be a non-access stratum (NAS) request received from the mobile terminal.

[0150] The method may further include receiving the SM from the SMS-GMSC for transmission to the mobile terminal.

[0151] The notification may be a context request received from a service mobility management node of the mobile terminal, and the method may further include: submitting a context response including an indication that the SM is to be transmitted to the service mobility management node; and receiving a context confirmation including a destination address of the service mobility management node for SM transmission from the service mobility management node, wherein the submitted message further includes the destination address of the service mobility management node.

[0152] The notification may be a context request received from a serving mobility management node of the mobile terminal, the message being submitted in a context response to the SMS-GSMC via the serving mobility management node and further comprising a destination address of the SMS-GSMC.

[0153] Receiving an indication from the SMS-GMSC that the SIM is to be delivered may include:

[0154] receiving an indication of a maximum retransmission time specifying how long the SMS-GMSC will store the SIM if the SIM cannot be delivered immediately and a capability indication indicating whether the SMS-GMSC supports receiving subsequent notifications of the availability of the mobile terminal for delivering the SIM; and the method further comprising:

[0155] Submitting an indication including a requested retransmission time and a capability confirmation to the SMS-GMSC, wherein the requested retransmission time indicates a time point at which the SMS-GMSC should retransmit the SM, and the capability confirmation indicates that the mobility management node supports the subsequent notification of the mobile terminal availability for transmitting the SM.

[0156] The second embodiment relates to a method of a mobility management node enabling delivery of a Mobile Terminated (MT) Short Message (SM) to a mobile terminal currently in an extended idle mode discontinuous reception (eDRX) mode.

[0157] The method comprises:

[0158] receiving a notification that the mobile terminal has exited the eDRX mode before a paging occasion occurs;

[0159] submitting a context request to another mobility management node serving the mobile terminal before the notification was received;

[0160] receiving, from the other mobility management node, a context response including an indication that the SM is to be transferred; and

[0161] The SM is received from the SMS-GMSC for delivery to the mobile terminal.

[0162] The message may be submitted directly to the SMS-GMSC.

[0163] The message may be submitted to the SMS-GMSC via a Home Subscription Server (HSS), the message submitted to the SMS-GMSC via the HSS further comprising an instruction instructing the HSS to provide a destination address of the mobility management to the SMS-GMSC.

[0164] The submitted message further indicates a time period defining a time until the mobile terminal enters the eDRX mode again.

[0165] Another embodiment relates to a mobility management node configured to enable delivery of a mobile terminated (MT) short message (SM) to a mobile terminal currently in an extended idle mode discontinuous reception (eDRX) mode, and comprising a processing unit and a memory containing instructions executable by the processing unit, whereby the mobility management node is operable to:

[0166] receiving an indication from a Short Message Service Gateway Mobile Switching Center (SMS-GMSC) that the SM is to be delivered;

[0167] receiving a notification that the mobile terminal has exited the eDRX mode before a paging occasion occurs; and

[0168] In response to the notification, a message is submitted to the SMS-GMSC indicating that the mobile terminal is available for delivery of the SIM.

[0169] The mobility management node is operable to submit the message directly to the SMS-GMSC.

[0170] The mobility management node is operable to submit the message to the SMS-GMSC via a Home Subscription Server (HSS).

[0171] The mobility management node is further operable to include in the message submitted to the SMS-GMSC via the HSS an instruction instructing the HSS to provide a destination address for the mobility management to the SMS-GMSC.

[0172] The notification may be a non-access stratum (NAS) request received from the mobile terminal.

[0173] The notification may be a context request received from a serving mobility management node of the mobile terminal, the mobility management node being further operable to:

[0174] submitting to the serving mobility management node a context response including an indication that the SM is to be transferred; and

[0175] A context acknowledgement is received from the serving mobility management node including a destination address of the serving mobility management node for SM transmission, wherein the submitted message further includes the destination address of the serving mobility management node.

[0176] The notification may be a context request received from a serving mobility management node of the mobile terminal, the mobility management node further operable to submit the message to the SMS-GSMC in a context response via the serving mobility management node, and further operable to include a destination address of the SMS-GSMC.

[0177] The mobility management node is further operable to, upon receiving an indication from the SMS-GMSC that the SIM is to be transferred:

[0178] receiving an indication of a maximum retransmission time specifying how long the SMS-GMSC will store the SIM if the SIM cannot be delivered immediately and a capability indication indicating whether the SMS-GMSC supports receiving subsequent notifications of the availability of the mobile terminal for delivering the SIM; and the method further comprising:

[0179] Submitting an indication including a requested retransmission time and a capability confirmation to the SMS-GMSC, wherein the requested retransmission time indicates a time point at which the SMS-GMSC should retransmit the SM, and the capability confirmation indicates that the mobility management node supports the subsequent notification of the mobile terminal availability for transmitting the SM.

[0180] Another embodiment relates to a mobility management node configured to enable delivery of a mobile terminated (MT) short message (SM) to a mobile terminal currently in an extended idle mode discontinuous reception (eDRX) mode, and comprising a processing unit and a memory containing instructions executable by the processing unit, whereby the mobility management node is operable to:

[0181] receiving a notification that the mobile terminal has exited the eDRX mode before a paging occasion occurs;

[0182] submitting a context request to another mobility management node serving the mobile terminal before the notification was received;

[0183] receiving, from the other mobility management node, a context response including an indication that the SM is to be transferred; and

[0184] The SM is received from the SMS-GMSC for delivery to the mobile terminal.

[0185] The mobility management node may be further operable to submit the message directly to the SMS-GMSC.

[0186] The mobility management node may be further operable to submit the message to the SMS-GMSC via a Home Subscription Server (HSS), the message submitted to the SMS-GMSC via the HSS further comprising an instruction instructing the HSS to provide a destination address of the mobility management to the SMS-GMSC.

[0187] The mobility management node may be further operable to include in the submitted message a time period specifying a time until the mobile terminal re-enters the eDRX mode.

[0188] Another embodiment relates to a first computer program comprising computer executable instructions which, when executed on a processing unit comprised in a device, cause the device to perform the steps listed in the first embodiment.

[0189] Another embodiment relates to a computer program product comprising a computer readable medium having the first computer program embodied thereon.

[0190] Another embodiment relates to a second computer program comprising computer executable instructions which, when executed on a processing unit included in a device, cause the device to perform the steps listed in the second embodiment above.

[0191] Another embodiment relates to a computer program product comprising a computer readable medium having the second computer program embodied thereon.

[0192] The invention has been described above mainly with reference to some embodiments. However, it is readily understood by a person skilled in the art that other embodiments than the embodiments disclosed above are also within the scope of the invention as defined by the attached patent claims.

Claims

1. A method for enabling a mobility management node (20) to transmit a mobile terminated MT short message SM to a mobile terminal (10), the method comprising: Receiving (S101) from a short message service gateway mobile switching center (40) SMS-GMSC an indication that the SM is to be transmitted to the mobile terminal (10) currently in an extended idle mode discontinuous reception (eDRX) mode; Receiving (S102) a notification that the mobile terminal (10) has exited the eDRX mode before a paging opportunity for the mobile terminal (10) occurs; as well as In response to the notification, a message is submitted (S103) to the SMS-GMSC (40) indicating to the SMS-GMSC (40) that the mobile terminal (10) is available for delivery of the SM.

2. The method of claim 1, wherein the message is submitted directly to the SMS-GMSC (40).

3. The method according to claim 1, the message being submitted to the SMS-GMSC via a Home Subscription Server (50) HSS.

4. The method according to claim 3, wherein: The message submitted to the SMS-GMSC via the HSS further includes an instruction instructing the HSS to provide a destination address of the mobility management to the SMS-GMSC.

5. The method according to any one of claims 1 to 4, wherein the notification is a non-access stratum (NAS) request received (S102) from the mobile terminal (10).

6. The method according to any one of claims 1 to 4, further comprising: The SM is received (S104) from the SMS-GMSC (40) for transmission to the mobile terminal (10).

7. The method according to any one of claims 1 to 3, wherein the notification is a context request received (S102b) from a serving mobility management node (30) of the mobile terminal (10), the method further comprising: submitting (S102c) to the serving mobility management node (30) a context response including an indication that the SM is to be transferred; as well as A context acknowledgement comprising a destination address of the serving mobility management node (30) for SM transmission is received (S102d) from the serving mobility management node (30), wherein the submitted (S103) message further comprises the destination address of the serving mobility management node (30).

8. According to the method described in any one of claims 1 to 3, the notification is a context request received (S102b) from the service mobility management node (30) of the mobile terminal, and the message is submitted (S103a) to the SMS-GSMC (40) in a context response (S102c) via the service mobility management node (30) and further includes a destination address of the SMS-GSMC (40).

9. The method according to any one of claims 1 to 4, receiving (S101) from the SMS-GMSC (40) an indication that the SM is to be transmitted comprises: receiving (S101a) an indication of a maximum retransmission time which specifies how long the SMS-GMSC (40) will store the SIM if the SIM cannot be immediately delivered, and a capability indication indicating whether the SMS-GMSC (40) supports receiving subsequent notifications of the availability of the mobile terminal for delivering the SIM, the method further comprising: Submitting (S101b) an indication including a requested retransmission time and a capability confirmation to the SMS-GMSC (40), wherein the requested retransmission time indicates the time point at which the SMS-GMSC (40) should retransmit the SM, and the capability confirmation indicates that the mobility management node (20) supports the subsequent notification of the availability of the mobile terminal for transmitting the SM.

10. A method for a mobility management node (30) to enable the transmission of a mobile terminated MT short message SM to a mobile terminal (10), the method comprising: Receiving (S102a) a notification that the mobile terminal (10) has exited the extended idle mode discontinuous reception eDRX mode before a paging occasion occurs; submitting (S102b) a context request to another mobility management node (20) serving the mobile terminal (10) before the notification is received; receiving (S102c) from the other mobility management node (20) a context response including an indication that the SM is to be transferred; as well as The SM is received (S105) from a Short Message Service Gateway Mobile Switching Centre (40) SMS-GMSC for transmission to the mobile terminal (10).

11. The method of claim 10, wherein the message is submitted directly to the SMS-GMSC (40).

12. The method according to claim 10, the message being submitted to the SMS-GMSC (40) via a Home Subscription Server (HSS), the message being submitted to the SMS-GMSC via the HSS further comprising an instruction instructing the HSS to provide a destination address of the mobility management to the SMS-GMSC.

13. The method according to any one of claims 10, 11 or 12, the submitted message further indicates a time period defining a time until the mobile terminal re-enters the eDRX mode.

14. A mobility management node (20) configured to enable the transmission of a mobile terminated MT short message (SM) to a mobile terminal (10), and comprising a processing unit (21) and a memory (23), the memory containing instructions (22) executable by the processing unit, whereby the mobility management node (20) is operable to: receiving from a short message service gateway mobile switching center (40) SMS-GMSC an indication that the SM is to be transmitted to the mobile terminal (10) currently in an extended idle mode discontinuous reception (eDRX) mode; receiving a notification that the mobile terminal (10) has exited the eDRX mode before a paging occasion occurs; as well as In response to the notification, a message is submitted indicating to the SMS-GMSC (40) that the mobile terminal (10) is available for delivery of the SM.

15. The mobility management node (20) of claim 14, the mobility management node (20) being operable to submit the message directly to the SMS-GMSC (40).

16. The mobility management node (20) of claim 14, the mobility management node (20) being operable to submit the message to the SMS-GMSC via a Home Subscription Server (50), HSS.

17. The mobility management node (20) of claim 16, the mobility management node (20) being further operable to include in the message submitted to the SMS-GMSC (40) via the HSS (50) an instruction instructing the HSS (50) to provide a destination address for the mobility management to the SMS-GMSC (40).

18. The mobility management node (20) according to any one of claims 14 to 17, wherein the notification is a Non-Access Stratum (NAS) request received from the mobile terminal (10).

19. The mobility management node (20) according to any one of claims 14 to 16, wherein the notification is a context request received (S102b) from a serving mobility management node (30) of the mobile terminal (10), the mobility management node further being operable to: submitting a context response including an indication that the SM is to be transferred to the serving mobility management node (30); and A context acknowledgement including a destination address of the serving mobility management node (30) for SM transmission is received from the serving mobility management node (30), wherein the submitted (S103) message further includes the destination address of the serving mobility management node (30).

20. According to the mobility management node (20) described in any one of claims 14 to 16, the notification is a context request received from the serving mobility management node (30) of the mobile terminal, and the mobility management node (20) is further operable to submit the message to the SMS-GSMC (40) in a context response (S102c) via the serving mobility management node (30), and is further operable to include a destination address of the SMS-GSMC (40).

21. The mobility management node (20) according to any one of claims 14 to 17, the mobility management node (20) being further operable to, upon receiving an indication from an SMS-GMSC (40) that the SIM is to be transferred: receiving an indication of a maximum retransmission time which specifies how long the SMS-GMSC (40) will store the SIM if the SIM cannot be immediately delivered, and a capability indication indicating whether the SMS-GMSC (40) supports receiving subsequent notifications of the availability of the mobile terminal for delivering the SIM; and Submitting an indication including a requested retransmission time and a capability confirmation to the SMS-GMSC (40), wherein the requested retransmission time indicates a point in time at which the SMS-GMSC (40) should retransmit the SM, and the capability confirmation indicates that the mobility management node (20) supports the subsequent notification of the availability of the mobile terminal for transmitting the SM.

22. A mobility management node (30) configured to enable the transmission of a mobile terminated MT short message (SM) to a mobile terminal (10), and comprising a processing unit (31) and a memory (33), the memory containing instructions (32) executable by the processing unit, whereby the mobility management node (30) is operable to: Receiving a notification that the mobile terminal (10) has exited the extended idle mode discontinuous reception (eDRX) mode before a paging opportunity occurs; submitting a context request to another mobility management node (20) serving the mobile terminal (10) before the notification was received; receiving from the other mobility management node (20) a context response including an indication that the SM is to be transferred; as well as The SM is received from a Short Message Service Gateway Mobile Switching Centre (40) SMS-GMSC for transmission to the mobile terminal (10).

23. The mobility management node (30) of claim 22, the mobility management node (30) being further operable to submit the message directly to the SMS-GMSC (40).

24. The mobility management node (30) according to claim 22, the mobility management node (30) is further operable to submit the message to the SMS-GMSC (40) via a home subscription server HSS, the message submitted to the SMS-GMSC via the HSS further comprising an instruction instructing the HSS to provide a destination address of the mobility management to the SMS-GMSC.

25. The mobility management node (20, 30) according to any one of claims 22 to 24, the mobility management node (20, 30) being further operable to include in the submitted message a time period specifying the time until the mobile terminal re-enters the eDRX mode.

26. A computer program product (22) comprising computer executable instructions which, when executed on a processing unit (21) comprised in a device (20), cause the device to perform the steps according to any one of claims 1 to 9.

27. A computer readable medium (23) having stored thereon a computer program product (22) according to claim 26.

28. A computer program product (32) comprising computer executable instructions which, when executed on a processing unit (31) comprised in a device (30), cause the device to perform the steps according to any one of claims 10 to 13.

29. A computer readable medium (33) having stored thereon a computer program product (32) according to claim 28.

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