System and method for seamless handoff of WLAN-UMTS interworking
First Claim
1. A method for performing handoff of user equipment (UE) connected to a wireless local area network (WLAN) to a mobile communication network in an interworking system between the WLAN and the mobile communication network including a gateway General Packet Radio Service (GPRS) support node (GGSN) and a serving GPRS support node (SGSN), the method comprising:
- receiving, by the SGSN, a pre-registration request message including a home IP address and an international mobile station identifier (IMSI) of the UE from the UE via the WLAN when the UE determines handoff in response to a link layer trigger while it communicates with the WLAN using a first temporary Internet protocol (IP) address;
performing, between the UE and the SGSN, authentication vector generation, authentication for the UE, and encryption key distribution processes based on the IMSI;
generating, by the GGSN, a second temporary IP address to be used by the UE in the mobile communication network, and transmitting a first message for requesting registration of the second temporary IP address to a home agent (HA) of the UE;
receiving, by the GGSN, a second message indicating registration of the second temporary IP address from the HA of the UE, and transmitting a third message to the UE via the WLAN indicating completion of pre-authentication for the UE and registration of the second temporary IP address; and
transmitting, by the UE, a fourth message indicating completion of pre-registration handoff for the UE to the HA of the UE when the handoff of the UE to the mobile communication network is completed.
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Accused Products
Abstract
A seamless handoff system and method reduces delay and packet loss during handoff of user equipment (UE) from a Wireless Local Area Network (WLAN) network to a Universal Mobile Telecommunication System (UMTS) network. The handoff system and method performs pre-registration and pre-authentication processes before the occurrence of a handoff, buffers packets being delivered to a UE during a handoff period, and forwards the buffered packets to the UE after completion of the handoff, thereby reducing packet loss that can occur during handoff.
84 Citations
28 Claims
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1. A method for performing handoff of user equipment (UE) connected to a wireless local area network (WLAN) to a mobile communication network in an interworking system between the WLAN and the mobile communication network including a gateway General Packet Radio Service (GPRS) support node (GGSN) and a serving GPRS support node (SGSN), the method comprising:
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receiving, by the SGSN, a pre-registration request message including a home IP address and an international mobile station identifier (IMSI) of the UE from the UE via the WLAN when the UE determines handoff in response to a link layer trigger while it communicates with the WLAN using a first temporary Internet protocol (IP) address;
performing, between the UE and the SGSN, authentication vector generation, authentication for the UE, and encryption key distribution processes based on the IMSI;
generating, by the GGSN, a second temporary IP address to be used by the UE in the mobile communication network, and transmitting a first message for requesting registration of the second temporary IP address to a home agent (HA) of the UE;
receiving, by the GGSN, a second message indicating registration of the second temporary IP address from the HA of the UE, and transmitting a third message to the UE via the WLAN indicating completion of pre-authentication for the UE and registration of the second temporary IP address; and
transmitting, by the UE, a fourth message indicating completion of pre-registration handoff for the UE to the HA of the UE when the handoff of the UE to the mobile communication network is completed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for performing handoff of user equipment (UE) connected to a wireless local area network (WLAN) to a mobile communication network by a gateway General Packet Radio Service (GPRS) support node (GGSN) in an interworking system between the WLAN and the mobile communication network including the GGSN and a serving GPRS support node (SGSN), the method comprising:
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performing authentication for the UE and encryption key distribution processes between the UE and the SGSN based on an international mobile station identifier (IMSI) of the UE after the UE determines handoff in response to a link layer trigger while it communicates with the WLAN using a first temporary Internet protocol (IP) address, and authentication vector generation;
generating, by the UE, a second temporary IP address to be used in the mobile communication network;
transmitting a first message for requesting registration of the second temporary IP address to a home agent (HA) of the UE; and
transmitting a third message indicating completion of pre-authentication for the UE and registration of the second temporary IP address to the UE via the WLAN upon receiving a second message indicating registration of the second temporary IP address from the HA of the UE so that the UE performs handoff to the mobile communication network. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A mobile communication system comprising:
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user equipment (UE) connected to a wireless local area network (WLAN) through interworking between a mobile communication network and the WLAN;
a serving General Packet Radio Service (GPRS) support node (SGSN) for receiving a pre-registration request message including a home IP address and an international mobile station identifier (IMSI) of the UE from the UE via the WLAN when the UE determines handoff in response to a link layer trigger while it communicates with the WLAN using a first temporary Internet protocol (IP) address, and performing authentication vector generation, authentication for the UE, and encryption key distribution processes with the UE based on the IMSI;
a gateway GPRS support node (GGSN) for generating a second temporary IP address to be used by the UE in the mobile communication network, transmitting a first message for requesting registration of the second temporary IP address, receiving a second message indicating registration of the second temporary IP address, and transmitting a third message indicating completion of pre-authentication for the UE and registration of the second temporary IP address to the UE via the WLAN; and
a home agent (HA) for registering the second temporary IP address upon receiving the first message from the GGSN, and transmitting the second message to the GGSN in response to the first message;
wherein the UE performs handoff to the mobile communication network upon receiving the third message, and transmits a fourth message indicating completion of pre-registration handoff for the UE to the HA. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
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Specification