System, devices, methods and programs for reducing service interruption during routing area change

Base station (16), comprising:

• means for sending to a core network a handover required message (14) having a mobile station identifier (IMSI), an identifier of at least one target cell routing area code (RAC) and a temporary logical link identity (TLLI);
• and
• means for receiving a handover command message (32) from said core network having a new temporary mobile subscriber identity (P-TMSI) for packet-switched (PS) services provided through a serving support node (12) of the core network for enabling a mobile station to determine a temporary logical link identity for addressing resources of said core network so that said mobile station is able to send PS data on an uplink before a routing area update (RAU) procedure is completed.

Method for execution in a core network (CN) of a mobile communications system prior to execution of a routing area update (RAU) procedure associated with a handover of a mobile station from a source cell to a target cell, comprising the steps of:

• receiving from a source base station (16) in said source cell a handover required message (14) having a temporary logical link identity (TLLI), a mobile station identifier (IMSI), and an identifier of at least one target cell (RAC), and
• sending to said source base station a handover command message (32) having a new packet-temporary mobile subscriber identity (P-TMSI) for transfer to said mobile station in ciphered form over a radio interface between said source base station and said mobile station so that said mobile station is able to send PS data on an uplink before said RAU procedure is completed.

Core network (CN) of a mobile communications system having a source base station in a source cell handing over a mobile station in said source cell to a target cell, comprising:

• means for receiving from said source base station (16) in said source cell a handover required message (14) having a temporary logical link identity (TLLI), a mobile station identifier (IMSI), and an identifier (RAC) of at least one target cell;
• and
• means for sending to said source base station a handover command message (32) having a new packet-temporary mobile subscriber identity (P-TMSI) for transfer to said mobile station in ciphered form over a radio interface between said source base station and said mobile station so that said mobile station is able to send packet-switched data on uplink before execution of a routing area update (RAU) procedure associated with said handing over of said mobile station.

Method for execution in a mobile station (40) in a source cell for utilizing both circuit-switched (CS) and packet-switched (PS) resources of a core network via radio link between said mobile station and a source base station in said source cell, said mobile station able to move to a target cell for utilizing said CS and PS resources via a radio link between said mobile station and a target base station, comprising the steps of:

• sending a measurement report to said source base station having radio information concerning said source cell and said target cell, and
• receiving a ciphered handover command from said source base station of said core network having a new temporary mobile subscriber identity (P-TMSI) from which a temporary logical link identity is derivable for use in said mobile station addressing said PS resources of the core network from a node (12) of said core network serving said target cell before a routing area update procedure is carried out.

Mobile station (40) for utilizing both circuit-switched (CS) and packet-switched (PS) resources of a core network via a radio link between said mobile station and a source base station in a source cell, said mobile station able to move to a target cell for utilizing said CS and PS resources via a radio link between said mobile station and a target base station, comprising:

• means for sending a measurement report to said source base station having radio information concerning said source cell and said target cell, and
• means for receiving a ciphered handover command from said source base station of said core network having a new temporary mobile subscriber identity (P-TMSI) from which a temporary logical link identity is derivable for use in said mobile station addressing said PS resources of the core network from a node (12) of said core network serving said target cell before a routing area update procedure is carried out.

Method for execution by a serving support node (12) of a mobile telecommunication network prior to a handover of a mobile station (MS) from a source cell to a target cell, comprising the steps of:

• receiving an MS information request message (18) from a mobile switching center (10) having an MS identifier (IMSI), an identifier of said target cell, and a temporary logical link identity (TLLI), and
• sending, in response to said MS information request message, an MS information response message (30) having a new temporary mobile subscriber identity (P-TMSI) for use in accessing packet-switched (PS) services provided by said serving support node before execution of a routing area update (RAU) procedure so that said MS is able to send PS data on an uplink during said RAU procedure.

Method for execution in a mobile communication system before execution of a routing area update (RAU) procedure associated with a handover of a mobile station (40) from a source cell to a target cell, comprising the steps of:

• sending to a core network (CN) from a source base station (16) in said source cell a handover required message (14) having a mobile station identifier (IMSI), an identifier of at least one target cell routing area code (RAC) and a temporary logical link identity (TLLI),
• sending to said source base station from said core network, in response to said handover required message, a handover command message (32) having a packet-temporary mobile subscriber identity (P-TMSI) for transfer to said mobile station in ciphered form over a radio interface between said source base station and said mobile station so that said mobile station is able to send packet-switched (PS) data on an uplink.

Mobile communication system having a source base station (16) in a source cell handing over a mobile station in said source cell to a target cell identified by said mobile station in a measurement report to said source base station, comprising:

• means for sending to a core network (CN) from said source base station (16) in said source cell a handover required message (14) having a mobile station identifier (IMSI), a routing area code (RAC) associated with said source cell, and a temporary logical link identity (TLLI);
• and
• means for sending to said source base station from said core network, in response to said handover required message, a handover command message (32) having a packet-temporary mobile subscriber identity (P-TMSI) for transfer to said mobile station in ciphered form over a radio interface between said source base station and said mobile station so that said mobile station is able to continue to send packet-switched data on an uplink during a routing area update (RAU) procedure associated with said handing over.