A Serving GPRS, General Packet Radio Service, Support Node,SGSN, comprising: a controller; and a non-transitory computer readable storage medium, storing instructions which, when executed by the controller, cause the controller to perform steps comprising: receiving a signaling request message from a mobile communication device via an access network; characterized by: the controller configured to execute the following steps: determining whether the mobile communication device operates in an idle mode with Extended Discontinuous Reception, EDRX, and whether there is any Mobile Terminated, MT, Short Message, SM, pending for the mobile communication device, in response to receiving the signaling request message, and transmitting a signaling response message indicating the pending of the MT SM to the mobile communication device via the access network in response to the mobile communication device being configured to operate in the idle mode with EDRX and there being at least one MT SM pending for the mobile communication device, wherein the signaling request message and the signaling response message are a Routing Area Update Request message and a Routing Area Update Accept message, respectively, or a Service Request message and a Service Accept message, respectively. a controller; and a non-transitory computer readable storage medium, storing instructions which, when executed by the controller, cause the controller to perform steps comprising: receiving a signaling request message from a mobile communication device via an access network; characterized by: the controller configured to execute the following steps: determining whether the mobile communication device operates in an idle mode with Extended Discontinuous Reception, EDRX, and whether there is any Mobile Terminated, MT, Short Message, SM, pending for the mobile communication device, in response to receiving the signaling request message, and transmitting a signaling response message indicating the pending of the MT SM to the mobile communication device via the access network in response to the mobile communication device being configured to operate in the idle mode with EDRX and there being at least one MT SM pending for the mobile communication device, wherein the signaling request message and the signaling response message are a Routing Area Update Request message and a Routing Area Update Accept message, respectively, or a Service Request message and a Service Accept message, respectively. the controller configured to execute the following steps: determining whether the mobile communication device operates in an idle mode with Extended Discontinuous Reception, EDRX, and whether there is any Mobile Terminated, MT, Short Message, SM, pending for the mobile communication device, in response to receiving the signaling request message, and transmitting a signaling response message indicating the pending of the MT SM to the mobile communication device via the access network in response to the mobile communication device being configured to operate in the idle mode with EDRX and there being at least one MT SM pending for the mobile communication device, wherein the signaling request message and the signaling response message are a Routing Area Update Request message and a Routing Area Update Accept message, respectively, or a Service Request message and a Service Accept message, respectively.