Method and apparatus for handoff of a wireless packet data services connection

• US 20020068570A1
• Filed: 12/06/2000
• Published: 06/06/2002
• Est. Priority Date: 12/06/2000
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Rezaiifar, Ramin, Abrol, Nischal
• Granted Patent: US 7,079,511 B2
• Time in Patent Office: Days
• US Class Current: 455/438
• CPC Class Codes: H04W 40/36 due to handover

Abstract

A novel method and apparatus is disclosed for performing seamless handoff of a mobile station (MS) between Radio Access Networks (RANs) that use different types of wireless interfaces. The described embodiments enable an MS to handoff between different RANs without causing routing ambiguity, and without substantial loss of network data. Upon moving from the coverage area of a first RAN using a first wireless interface to the coverage area of a second RAN using a second wireless interface, an MS determines whether routing ambiguity may result from the change of RAN and, based on the determination, triggers a re-registration of its network address. A foreign agent (FA) within a packet data serving node (PDSN) monitors network address re-registrations in order to determine whether multiple RAN-PDSN (R-P) connections are being created for the same MS. Based on this determination, the PDSN terminates redundant R-P network connections resulting from movement of the MS between different RANs.

Claims

1. A method of performing a handoff of a mobile station between a first radio access network of a first type and a second radio access network of a second type, comprising:

determining, at the mobile station, whether changing from communicating over the first radio access network to communicating over the second radio access network will cause routing ambiguity for data sent to and from the mobile station; and

triggering, at the mobile station, a re-registration of a network address of the mobile station if changing from communicating over the first radio access network to communicating over the second radio access network will cause routing ambiguity for data sent to and from the mobile station.

2. In a packet data serving node of a communications network, a method of compensating for a handoff of a mobile station between a radio access network of a first type and a radio access network of a second type, comprising:

determining, at the packet data serving node, whether multiple radioaccess-network-to-packet-data-serving-node (R-P) connections are being created for the same mobile station; and

terminating, at the packet data serving node, redundant R-P connections resulting from movement of the mobile station between a radio access network of a first type and a radio access network of a second type.

3. The method of claim 2, further comprising monitoring, at the packet data serving node, network address re-registrations of mobile stations.

4. A mobile station, comprising:

a control processor; and

a memory coupled to the control processor and containing instructions executable by the processor to determine whether handing off from a radio access network of a first type to a radio access network of a second type will cause routing ambiguity for data sent to and from the mobile station, and triggering a re-registration of a network address of the mobile station based on the determination.

5. A mobile station, comprising:

means for determining whether handing off communications from a radio access network of a first type to a radio access network of a second type will cause routing ambiguity for data sent to and from the mobile station; and

2means for triggering a re-registration of a network address of the mobile station based on the determination.