Communication system and communication controlling method

Abstract

A communication method in LIPA/SIPTO architecture is provided which, when a user equipment (UE) is to connect from a serving area to an external network, allows re-selection of an optimal gateway. The communication method allows selecting a gateway apparatus physically or topologically close to a site, where the user equipment is attached.

1 . A communication method in Selected IP Traffic Offload (SIPTO) architecture, the method comprising:
 a mobility management entity (MME) sending a delete session request to a gateway apparatus, when the MME decides that it is necessary to perform re-allocation of a gateway apparatus on receipt of a tracking area (TA) update signal from the user equipment; and   the MME performing the re-allocation of the gateway apparatus.   
     
     
         2 . A communication system in Selected IP Traffic Offload (SIPTO) architecture, the system comprising:
 a Serving General Packet Radio Service Support Node (SGSN) sending a delete session request to a gateway apparatus, when the SGSN decides that it is necessary to perform re-allocation of a gateway apparatus on receipt of a routing area (RA) update signal from the user equipment; and   the SGSN performing the re-allocation of the gateway apparatus.   
     
     
         3 . The communication method according to  claim 1 , wherein the gateway apparatus includes at least one of a serving gateway apparatus, a packet data network gateway apparatus, and a Gateway General Packet Radio Service Support Node (GGSN). 
     
     
         4 . The communication method according to  claim 2 , wherein the gateway apparatus includes at least one of a serving gateway apparatus, a packet data network gateway apparatus, and a Gateway General Packet Radio Service Support Node (GGSN). 
     
     
         5 . A communication system in Selected IP Traffic Offload (SIPTO) architecture, the system comprising:
 a user equipment;   a mobility management entity (MME); and   a plurality of gateway apparatuses, wherein   the user equipment transmits a tracking area (TA) update signal to the MME;   the MME sends a delete session request to the gateway apparatus, when the MME decides that it is necessary to perform re-allocation of a gateway apparatus on receipt of the tracking area (TA) update signal from the user equipment; and   the MME performs the re-allocation of the gateway apparatus.   
     
     
         6 . A communication system in Selected IP Traffic Offload (SIPTO) architecture, the system comprising:
 a user equipment;   a Serving General Packet Radio Service Support Node (SGSN); and   a plurality of gateway apparatuses, wherein   the user equipment transmits a routing area (RA) update to the SGSN;   the SGSN sends a delete session request to the gateway apparatus, when the SGSN decides that it is necessary to perform re-allocation of a gateway apparatus on receipt of the routing area (RA) update signal from the user equipment; and   the SGSN performs the re-allocation of the gateway apparatus.   
     
     
         7 . The communication system according to  claim 5 , wherein the gateway apparatus includes at least one of a serving gateway apparatus, a packet data network gateway apparatus, and a Gateway General Packet Radio Service Support Node (GGSN). 
     
     
         8 . The communication system according to  claim 6 , wherein the gateway apparatus includes at least one of a serving gateway apparatus, a packet data network gateway apparatus, and a Gateway General Packet Radio Service Support Node (GGSN). 
     
     
         9 . A user equipment in a communication system by Selected IP Traffic Offload (SIPTO) architecture, wherein the user equipment transmits a tracking area (TA) update signal to a mobility management entity (MME),
 when the MME decides that it is necessary to perform re-allocation of a gateway apparatus on receipt of the tracking area (TA) update signal from the user equipment, the MME sending a delete session request to a gateway apparatus to perform the re-allocation of a gateway apparatus to which the user equipment is to be connected.   
     
     
         10 . A user equipment in a communication system by Selected IP Traffic Offload (SIPTO) architecture, wherein the user equipment transmits a routing area (RA) update signal to a Serving General Packet Radio Service Support Node (SGSN),
 when the SGSN decides that it is necessary to re-allocation of a gateway apparatus on receipt of the routing area (RA) update signal from the user equipment, the SGSN sending a delete session request to a gateway apparatus to perform the re-allocation of a gateway apparatus to which the user equipment is to be connected.   
     
     
         11 . The user equipment according to  claim 9 , wherein the gateway apparatus includes at least one of a serving gateway apparatus, a packet data network gateway apparatus, and a Gateway General Packet Radio Service Support Node (GGSN). 
     
     
         12 . The user equipment according to  claim 10 , wherein the gateway apparatus includes at least one of a serving gateway apparatus, a packet data network gateway apparatus, and a Gateway General Packet Radio Service Support Node (GGSN).