METHOD AND SYSTEM FOR IMPLEMENTING INTER-ACCESS NETWORK HANDOFF IN ACTIVE STATE IN HRPD NETWORK

• US 20080062955A1
• Filed: 11/16/2007
• Published: 03/13/2008
• Est. Priority Date: 05/16/2005
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: LI, Zhiming, GAO, Quanzhong, HE, Qingrong
• Granted Patent: US 8,054,801 B2
• Time in Patent Office: Days
• US Class Current: 370/348
• CPC Class Codes: H04W 36/0066 of control information between different types of networks in order to establish a new radio link in the target network
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 36/10 Reselecting an access point controller

Abstract

A method and system for implementing an inter-Access Network (AN) handoff in an active state in a High Rate Packet Data (HRPD) Network. The method mainly includes determining that an inter-AN handoff operation is necessary and initiating a handoff procedure to perform the inter-AN handoff, sending data to be transmitted to an access terminal to the destination AN in advance in the handoff procedure, and then sending the access terminal the data to be transmitted to the access terminal by the source AN or the destination AN according to the result of the handoff procedure. With the method according to the present invention, the continuity of a service may be improved. Even if the inter-AN handoff procedure fails, the source PCF may send data information obtained upon the start of the handoff to the access terminal when the access terminal returns to the source AN since the source PCF may receive data from the PDSN throughout the handoff procedure. As a result, the continuity of a service may be improved.

Claims

1. A method for implementing an inter-Access Network handoff, hereinafter referred to as inter-AN handoff, in an active state in a High Rate Packet Data network, hereinafter referred to as HRPD network, comprising:

determining that an inter-AN handoff operation is necessary, and initiating a handoff procedure;

in the inter-AN handoff procedure, establishing a connection between a destination Access Network, hereinafter referred to as destination AN, and a Packet Data Service Network, hereinafter referred to as PDSN, before an access terminal establishes a connection with the destination AN, and sending, by the PDSN, data to the destination AN or Packet Control Function, hereinafter referred to as PCF; and

after the access terminal has established a connection with the destination AN, sending from the destination AN or PCF to the access terminal the data received from the PDSN.

2. The method according to claim 1, wherein determining that an inter-AN handoff operation is necessary and initiating a handoff procedure comprises:

determining, by a source Access Network, hereinafter referred to as source AN, that the inter-AN handoff operation is necessary according to a received route update message, and determining the destination AN corresponding to the source AN; and

sending, by the source AN, a handoff request message to the destination AN.

3. The method according to claim 2, wherein when the handoff is performed between Access Networks belonging to different PCFs, establishing a connection between a destination AN and a PDSN in the inter-AN handoff procedure before an access terminal establishes a connection with the destination AN and sending data by the PDSN to the destination AN or PCF comprises:

in response to receiving the handoff request message sent from the source AN, sending, by the destination AN, a connection establishment request to the destination PCF, and establishing a connection between the destination PCF and the destination AN;

registering, by the destination PCF, to the PDSN, and establishing a connection between the destination PCF and the PDSN; and

when a source PCF requests to stop sending data, sending, by the PDSN, data to the destination PCF and stopping sending data to the source PCF.

4. The method according to claim 3, wherein sending data by the PDSN to the destination PCF and stopping sending data by the PDSN to the source PCF when the source PCF requests to stop sending data comprises:

when disconnecting of an air interface connection between the source AN and the access terminal is determined, sending, by the source PCF, a stop-sending-data message to the PDSN requesting the PDSN to stop sending data to the source PCF; and

in response to receiving the stop-sending-data message from the source PCF, starting, by the PDSN, sending data to the destination PCF if the PDSN has not sent data to the destination PCF, while stopping sending data to the source PCF.

5. The method according to claim 2, wherein when a handoff is performed between Access Networks belonging to different PCFs, establishing a connection between a destination AN and a PDSN in the inter-AN handoff procedure before an access terminal establishes a connection with the destination AN and sending data by the PDSN to the destination AN or PCF comprises:

in response to receiving the handoff request message sent from the source AN, sending, by the destination AN, a connection establishment request to the destination PCF, and establishing a connection between the destination PCF and the destination AN;

registering, by the destination PCF, to the PDSN, and establishing a connection between the destination PCF and the PDSN; and

after the connection between the destination PCF and the PDSN has been established, sending, by the PDSN, a bi-cast indication message to the source AN to notify the source AN or PCF that the PDSN will send data to the destination PCF or AN and the source AN or PCF simultaneously.

6. The method according to claim 5, wherein sending a bi-cast indication message by the PDSN to the source AN to notify the source AN or PCF that the PDSN will send data to the destination PCF or AN and the source AN or PCF simultaneously after the connection between the destination PCF and the PDSN has been established comprises:

when the existing connection between the destination PCF and the PDSN is determined as the inter-AN handoff, sending, by the PDSN, the bi-cast indication message.

7. The method according to claim 6, wherein the data comprises:

real-time service data and non-real-time service data.

8. The method according to claim 7, further comprising:

in response to receiving the bi-cast Indication message, stopping, by the source AN, sending real-time service packets while continuing to send non-real-time service packets.

9. The method according to claim 1, further comprising:

sending, by the destination AN, a handoff complete message to the source AN when the access terminal can receive data via the destination AN; and

in response to receiving the handoff complete message, interchanging, by the source AN, information with the source PCF, and releasing the connection between the source PCF and the source AN.

10. The method according to claim 1, wherein establishing a connection between a destination AN and a PDSN in the inter-AN handoff procedure before an access terminal establishes a connection with the destination AN and sending data by the PDSN to the destination AN or PCF further comprises:

sending, by the source AN, a channel assignment message to the access terminal according to a handoff reply message sent from the destination AN, and interchanging, by the source AN, information with the source PCF instructing to disconnect an air interface connection when receiving a reply from the access terminal, or, interchanging, by the source AN, information with the source PCF instructing to disconnect the air interface connection directly after sending the channel assignment message without waiting for the replay from the access terminal.

11. The method according to claim 10, wherein sending a channel assignment message by the source AN to the access terminal according to a handoff reply message sent from the destination AN and interchanging information by the source AN with the source PCF instructing to disconnect an air interface connection when receiving a reply from the access terminal or the source AN interchanging information by the source AN with the source PCF instructing to disconnect the air interface connection directly after sending the channel assignment message without waiting for the replay from the access terminal comprises:

sending, by the source AN, the channel assignment message to the access terminal, handing off the access terminal to the destination AN, and allocating, by the destination AN, a Uni-cast Access Terminal Identifier, hereinafter referred to as UATI, for the access terminal, so as to complete assignment of the UATI;

interchanging, by the destination AN, information with the destination PCF so as to establish an air interface connection of the destination AN;

Or,

sending, by the source AN, a UATI assignment message to the access terminal, and sending the channel assignment message to the access terminal when the UATI assignment is completed, and completing the channel assignment; and

interchanging, by the destination AN, information with the destination PCF so as to establish an air interface connection of the destination AN.

12. The method according to claim 1, wherein establishing a connection between a destination AN and a PDSN in the inter-AN handoff procedure before an access terminal establishes a connection with the destination AN and sending data by the PDSN to the destination AN or PCF comprises:

for a handoff between Access Networks belonging to different PCFs, sending, by the PDSN, data to be transmitted to the access terminal simultaneously to the source PCF to which the source AN belongs and the destination PCF to which the destination AN belongs.

13. The method according to claim 12, wherein establishing a connection between a destination AN and a PDSN in the inter-AN handoff procedure before an access terminal establishes a connection with the destination AN and sending data by the PDSN to the destination AN or PCF further comprises:

saving the data to be transmitted to the access terminal in Base Transceiver Stations corresponding to the source AN and the destination AN respectively.

14. The method according to claim 12, further comprising:

when the handoff procedure from the source AN to the destination AN fails, sending the access terminal the data to be transmitted to the access terminal by the source AN and the source PCF.

15. A system for implementing an inter-AN handoff in an active state in an HRPD Network, comprising a source AN, a source PCF, a destination AN, a destination PCF and a PDSN, wherein

after the source AN initiates an inter-AN handoff procedure, the destination AN establishes a connection with the PDSN before an access terminal establishes a connection with the destination AN, and the PDSN sends data to the destination AN or PCF;

and

after the access terminal has established a connection with the destination AN, the destination AN or PCF sends the data received from the PDSN to the access terminal.

16. The system according to claim 15, wherein when the source PCF requests to stop sending data, the PDSN sends data to the destination PCF while stopping sending data to the source PCF.

17. The system according to claim 15, wherein after the connection between the destination PCF and the PDSN has been established, the PDSN sends a bi-cast indication message to the source AN to notify the source AN or PCF that the PDSN will send data to the destination PCF or AN and the source AN or PCF simultaneously.