Mobile communication system, mobile station, switching station, and location registration method for mobile station

A mobile station used in a mobile communication system including a first SGSN (Serving GPRS Support Node) or a first MME (Mobility Management Entity), a second SGSN or a second MME and a plurality of MSCs/VLRs (Mobile Switching Centers/Visited Location Registers), said mobile station comprising:

• a receiver configured to receive a TMSI (Temporary Mobile Station Identifier) including an NRI (Network Resource Identifier) indicating one MSC/VLR, from said one MSC/VLR via said first SGSN or said first MME, selected from said plurality of MSCs/VLRs by said first SGSN or said first MME using an IMSI (International Mobile-Station Subscription Identifier);
• and
• a transmitter configured to transmit an Attach Request including said TMSI to said second SGSN or said second MME, in a case that said mobile station moves to an area under a control of said second SGSN or said second MME from an area under a control of said first SGSN or said first MME but in an area under a control of said MSC/VLR area,
• wherein said second SGSN or said second MME selects said one MSC/VLR based on said TMSI provided by said mobile station.

A communication method for a mobile communication system, the method comprising:

• receiving, by a mobile station, a TMSI (Temporary Mobile Station Identifier) including an NRI (Network Resource Identifier) indicating one MSC/VLR (Mobile Switching Center/Visited Location Register), from said one MSC/VLR via a first SGSN (Serving GPRS Support Node) or a first MME (Mobility Management Entity), selected from a plurality of MSCs/VLRs by said first SGSN or said first MME using an IMSI (International Mobile-Station Subscription Identifier);
• transmitting, by said mobile station, an Attach Request including said TMSI to a second SGSN or a second MME, in a case that said mobile station moves to an area under a control of said second SGSN or said second MME from an area under a control of said first SGSN or said first MME but in an area under a control of said MSC/VLR area;
• and
• selecting, by said second SGSN or said second MME, said one MSC/VLR based on said TMSI provided by said mobile station.

A communication method of a mobile station used in a mobile communication system including a first SGSN (Serving GPRS Support Node) or a first MME (Mobility Management Entity), a second SGSN or a second MME and a plurality of MSCs/VLRs (Mobile Switching Centers/Visited Location Registers), said method comprising:

• receiving a TMSI (Temporary Mobile Station Identifier) including an NRI (Network resource Identifier) indicating one MSC/VLR, from said one MSC/VLR via said first SGSN or said first MME, selected from said plurality of MSCs/VLRs by said first SGSN or said first MME using an IMSI (International Mobile-Station Subscription Identifier);
• and
• transmitting an Attach Request including said TMSI to said second SGSN or said second MME, in a case that said mobile station moves to an area under a control of said second SGSN or said second MME from an area under a control of said first SGSN or said first MME but in an area under a control of said MSC/VLR area,
• wherein said second SGSN or said second MME selects said one MSC/VLR based on said TMSI provided by said mobile station.