Layer 2 tunneling of data during handover in a wireless communication system

• US 8,437,306 B2
• Filed: 08/07/2008
• Issued: 05/07/2013
• Est. Priority Date: 08/08/2007
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Attar, Rashid Ahmed Akbar, Meylan, Arnaud, Ho, Sai Yiu Duncan, Grilli, Francesco, Tenny, Nathan Edward, Barany, Peter Anthony
• Primary Examiner(s): TORRES, MARCOS L
• Application Number:
  US12/187,539
• Publication Number:
  US 20090124259A1
• Time in Patent Office: 1,734 Days
• Field of Search: 370/331, 370/328, 370/349, 455436-444, 709227-229, 709238-239
• US Class Current: 370/331
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/34 ensuring sequence integrity, e.g. using sequence numbers
• CPC Class Codes: H04W 28/02 Traffic management, e.g. flow control or congestion control
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 92/20 between access points

Abstract

Techniques for sending data during handover with Layer 2 tunneling are described. In one design, a user equipment (UE) sends first Layer 2 packets to a source base station prior to handover to a target base station. The UE sends at least one second Layer 2 packet to the target base station, which identifies the second Layer 2 packet(s) as being intended for the source base station and thus forwards the second Layer 2 packet(s) to the source base station via a Layer 2 tunnel. The UE sends third Layer 2 packets to the target base station after the handover. The target base station processes the third Layer 2 packets to obtain IP packets and sends the IP packets to a serving gateway after a trigger condition, which may be defined to achieve in-order delivery of IP packets from the source and target base stations to the serving gateway.

Claims

1. A method of sending data in a wireless communication system, comprising:

sending first Layer 2 packets from a mobile entity to a source base station prior to handover of a user equipment (UE) from the source base station to a target base station, the first Layer 2 packets being indicated for the source base station by a destination indicator consisting of one or more bits of a Radio Link Control (RLC) header in each of the first Layer 2 packets set to a first value assigned to the source base station, wherein the RLC header is in a protocol data unit (PDU) of an RLC sublayer that is distinct from a lower Media Access Control (MAC) sublayer;

sending at least one second Layer 2 packet from the mobile entity directly to the target base station, the at least one second Layer 2 packet being indicated for the source base station by the destination indicator set to the first value for forwarding from the target base station to the source base station via a Layer 2 tunnel; and

sending third Layer 2 packets from the mobile entity to the target base station after the handover, the third Layer 2 packets being indicated for the target base station by the destination indicator set to a second value assigned to the target base station.

2. The method of claim 1, further comprising:

setting the destination indicator of each first Layer 2 packet and each second Layer 2 packet to the first value for the source base station; and

setting the destination indicator of each third Layer 2 packet to the second value for the target base station.

3. The method of claim 1, further comprising:

processing first Internet Protocol (IP) packets in accordance with a first Layer 2 configuration for the source base station to obtain the first and second Layer 2 packets; and

processing second IP packets in accordance with a second Layer 2 configuration for the target base station to obtain the third Layer 2 packets, wherein the second Layer 2 configuration is different from the first Layer 2 configuration.

4. The method of claim 3, further comprising:

receiving from the target base station a message indicating a connection between the target base station and a serving gateway is set up;

using the first Layer 2 configuration prior to receiving the message; and

using the first or second Layer 2 configuration after receiving the message.

5. The method of claim 1, further comprising:

receiving from the target base station a message indicating a connection between the target base station and a serving gateway is set up; and

switching to the connection in response to receiving the message.

6. The method of claim 1, further comprising:

sending a flush message to indicate that no more Layer 2 packets are indicated for the source base station, the flush message being received by the target base station and forwarded to the source base station.

7. The method of claim 1, wherein the first, second, and third Layer 2 packets comprise RLC PDUs.

8. An apparatus for wireless communication, comprising:

at least one processor configured to send first Layer 2 packets from a mobile entity to a source base station prior to handover of a user equipment (UE) from the source base station to a target base station, the first Layer 2 packets being indicated for the source base station by a destination indicator consisting of one or more bits of a Radio Link Control (RLC) header in each of the first Layer 2 packets set to a first value assigned to the source base station, wherein the RLC header is in a protocol data unit (PDU) of an RLC sublayer that is distinct from a lower Media Access Control (MAC) sublayer, to send at least one second Layer 2 packet from mobile entity directly to the target base station, the at least one second Layer 2 packet being indicated for the source base station by the destination indicator set to the first value for forwarding from the target base station to the source base station via a Layer 2 tunnel, and to send third Layer 2 packets from the mobile entity to the target base station after the handover, the third Layer 2 packets being indicated for the target base station by the destination indicator set to a second value assigned to the target base station.

9. The apparatus of claim 8, wherein the at least one processor is configured to set the destination indicator of each first Layer 2 packet and each second Layer 2 packet to the first value for the source base station, and to set the destination indicator of each third Layer 2 packet to the second value for the target base station.

10. The apparatus of claim 8, wherein the at least one processor is configured to process first Internet Protocol (IP) packets in accordance with a first Layer 2 configuration for the source base station to obtain the first and second Layer 2 packets, and to process second IP packets in accordance with a second Layer 2 configuration for the target base station to obtain the third Layer 2 packets, wherein the second Layer 2 configuration is different from the first Layer 2 configuration.

11. An apparatus for wireless communication, comprising:

means for sending first Layer 2 packets from a mobile entity to a source base station prior to handover of a user equipment (UE) from the source base station to a target base station, the first Layer 2 packets being indicated for the source base station by a destination indicator consisting of one or more bits of a Radio Link Control (RLC) header in each of the first Layer 2 packets set to a first value assigned to the source base station, wherein the RLC header is in a protocol data unit (PDU) of an RLC sublayer that is distinct from a lower Media Access Control (MAC) sublayer;

means for sending at least one second Layer 2 packet from the mobile entity directly to the target base station, the at least one second Layer 2 packet being indicated for the source base station by the destination indicator set to the first value for forwarding from the target base station to the source base station via a Layer 2 tunnel; and

means for sending third Layer 2 packets to the target base station after the handover, the third Layer 2 packets being indicated for the target base station by the destination indicator set to a second value assigned to the target base station.

12. The apparatus of claim 11, further comprising:

means for setting the destination indicator of each first Layer 2 packet and each second Layer 2 packet to the first value for the source base station; and

means for setting the destination indicator of each third Layer 2 packet to the second value for the target base station.

13. The apparatus of claim 11, further comprising:

means for processing first Internet Protocol (IP) packets in accordance with a first Layer 2 configuration for the source base station to obtain the first and second Layer 2 packets; and

means for processing second IP packets in accordance with a second Layer 2 configuration for the target base station to obtain the third Layer 2 packets, wherein the second Layer 2 configuration is different from the first Layer 2 configuration.

14. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing at least one computer to send first Layer 2 packets to a source base station prior to handover of a user equipment (UE) from the source base station to a target base station, the first Layer 2 packets being indicated for the source base station by a destination indicator consisting of one or more bits of a Radio Link Control (RLC) header in each of the first Layer 2 packets set to a first value assigned to the source base station, wherein the RLC header is in a protocol data unit (PDU) of an RLC sublayer that is distinct from a lower Media Access Control (MAC) sublayer,

code for causing the at least one computer to send at least one second Layer 2 packet to the target base station, the at least one second Layer 2 packet being indicated for the source base station by the destination indicator set to the first value for forwarding from the target base station to the source base station via a Layer 2 tunnel, and

code for causing the at least one computer to send third Layer 2 packets to the target base station after the handover, the third Layer 2 packets being indicated for the target base station by the destination indicator set to a second value assigned to the target base station.