METHOD AND APPARATUS FOR NON-ACCESS STRATUM MESSAGE PROCESSING DURING HANDOVER IN EVOLVED NETWORK

• US 20100142367A1
• Filed: 02/12/2010
• Published: 06/10/2010
• Est. Priority Date: 08/13/2007
• 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: WANG, Qiang, QIU, Yong, HUANG, Ying, ZHANG, Hongzhuo
• Granted Patent: US 8,665,820 B2
• Time in Patent Office: Days
• US Class Current: 370/216
• CPC Class Codes: H04W 36/0079 in case of hand-off failure or rejection
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 92/12 between access points and access point controllers
• CPC Class Codes: H04W 92/20 between access points

Abstract

A method and an apparatus for non-access stratum (NAS) message processing during handover in an evolved network are provided. The method includes the following steps. An evolved packet core (EPC) receives a message which indicates that a UE is being handed over sent by a source evolved NodeB (S-eNB), and stops sending an NAS message to the UE temporarily. The EPC receives a message which indicates that the UE returns to an S-eNB service area sent by the S-eNB. The EPC sends the NAS message to the UE through the S-eNB, if needed. With the method and the apparatus, the EPC can acquire a location of the UE in time in the case of a handover failure of the UE, a time limit of a retransmission timer is set precisely, and a specific implementation for forwarding an NAS message through an X2 interface is provided.

Claims

1. A method for Non-access Stratum (NAS) message processing during handover in an evolved network, comprising:

sending, by an Evolved Packet Core (EPC), a direct-transfer message to an Source-eNodeB (S-eNB), wherein the direct-transfer message contains an NAS message to be sent by the EPC to a User Equipment (UE); and

receiving, by the EPC, a message, which indicates that the UE is being handed over, sent by the S-eNB, wherein the message which indicates that the UE is being handed over is a direct transfer failure message or a direct transfer response message which contains a cause value and the NAS message that fails to be sent.

2. The method of claim 1, wherein the NAS message that fails to be sent is an NAS message received from the EPC before or after the S-eNB sends a handover command to the UE.

3. The method of claim 1, comprising:

sending, by the EPC, the NAS message that fails to be sent to the UE through the S-eNB when it is necessary to send the NAS message to the UE.

4. The method of claim 2, comprising:

sending, by the EPC, the NAS message that fails to be sent to the UE through the S-eNB when it is necessary to send the NAS message to the UE.

5. The method of claim 1, comprising:

buffering, by the EPC, the NAS message to be sent to the UE in response to the receiving of the message which indicates that the UE is being handed over sent by the S-eNB; and

sending, by the EPC, the NAS message buffered by the EPC to the UE through the S-eNB when it is necessary to send the NAS message to the UE.

6. The method of claim 1, comprising:

starting, by the EPC, a retransmission timer, after the EPC receives the message which indicates that the UE is being handed over sent by the S-eNB;

sending, by the EPC, the NAS message that fails to be sent to the UE through the S-eNB when it is necessary to send the NAS message to the UE after the retransmission timer expires and the handover fails.

7. A Mobility Management Entity (MME), comprising:

a message sending module and a message receiving module, wherein the message sending module is configured to enable an EPC to send a direct-transfer message to an S-eNB, wherein the direct-transfer message contains an NAS message which is to be sent to a UE by the EPC; and

the message receiving module is configured to enable the EPC to receive a message, which indicates that the UE is being handed over, sent by the S-eNB, wherein the message which indicates that the UE is being handed over is a direct transfer failure message or direct transfer response message which contains a cause value and an NAS message that fails to be sent.

8. The MME of claim 7, further comprising:

a timer start module, configured to enable the EPC to start a retransmission timer;

wherein the message sending is further configured to enable the EPC to send the NAS message that fails to be sent to the UE through the S-eNB when it is necessary to send the NAS message to the UE after the retransmission timer expires if the handover fails.

9. The MME of claim 7, further comprising:

a timer stop module, configured to enable the EPC to stop the retransmission timer when the EPC receives a handover complete message sent by a Target-eNodeB (T-eNB);

wherein the message sending module is further configured to enable the EPC to send the NAS message to the UE through the T-eNB when it is necessary to send the NAS message to the UE after timer stop module stops the retransmission timer.

10. A method for Non-access Stratum (NAS) message processing during handover in an evolved network, comprising:

receiving, by an Evolved Packet Core (EPC), a message which indicates that a User Equipment (UE), is being handed over sent by a Source-eNodeB (S-eNB), wherein the message which indicates that the UE is being hand over is a direct transfer failure message or a direct transfer response message;

buffering, by the EPC, an NAS message to be sent to the UE;

receiving, by the EPC, a message which indicates that the UE returns to the S-eNB service area sent by the S-eNB when the handover fails; and

sending, by the EPC, the NAS message to the UE through the S-eNB when it is necessary to send the NAS message to the UE.

11. The method of claim 10, wherein before the receiving, by the EPC, the message, which indicates that the UE is being handed over, sent by the S-eNB, the method further comprises:

sending, by the EPC, a direct-transfer message to the S-eNB, wherein the direct-transfer message contains an NAS message to be sent to the UE;

wherein the message which indicates that the UE is being handed over from the S-eNB is a direct transfer failure message or a direct transfer response message which contains a cause value and the NAS message to be sent to the UE.

12. The method of claim 10, wherein the NAS message to be sent to the UE contains in the direct transfer failure message or the direct transfer response message is an NAS message received from the EPC before the S-eNB sends a handover command to the UE, or the NAS message to be sent to the UE contained in the direct transfer failure message or the direct transfer response message is an NAS message received from the EPC after the S-eNB sends a handover command to the UE.

13. A method for NAS message processing during handover in an evolved network, comprising:

receiving, by an Evolved Packet Core (EPC), a message which indicates that a User Equipment (UE), is being handed over, sent by a Source-eNodeB (S-eNB);

starting, by the EPC, a retransmission timer; and

sending, by the EPC, the Non-access Stratum (NAS), message to the UE through the S-eNB when it is necessary to send an NAS message to the UE after the retransmission timer expires and the handover fails.

14. The method of claim 13, wherein the retransmission timer is an S1 interface application part (S1-AP) protocol retransmission timer.

15. The method of claim 13, wherein before the EPC receives the message which indicates that the UE is being handed over sent by the S-eNB, the method further comprises:

sending, by the EPC, a direct-transfer message to the S-eNB, wherein the direct-transfer message contains the NAS message which is to be sent to the UE;

wherein the message, which indicates that the UE is being handed over, sent by the S-eNB is a direct transfer failure message or a direct transfer response message which contains a cause value and time information.

16. The method of claim 13, wherein if the handover is successful, after the EPC receives the message that the UE is being handed over sent by the S-eNB and starts the retransmission timer, the method further comprises:

receiving, by the EPC, a handover complete message sent by a T-eNB;

stopping, by the EPC, the retransmission timer; and

sending, by the EPC, the NAS message to the UE through the S-eNB when it requires sending the NAS message to the UE.