Handover processing method of mobile communication system

• US 7,315,741 B2
• Filed: 08/21/2003
• Issued: 01/01/2008
• Est. Priority Date: 08/21/2002
• Status: Expired due to Fees

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Chun, Chang-Hyen
• Primary Examiner(s): Feild, Joseph
• Assistant Examiner(s): DESIR, PIERRE LOUIS
• Application Number:
  US10/644,996
• Publication Number:
  US 20040038681A1
• Time in Patent Office: 1,594 Days
• Field of Search: 455/442, 455/436, 455/522, 455/434, 370/352
• US Class Current: 455/436
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04W 36/0072 of resource information of target access point
• CPC Class Codes: H04W 36/08 Reselecting an access point

Abstract

In a handover processing method of a mobile communication system, when a radio link set (active set update) message is received from a RNC (radio network controller), the method includes performing a backup of a present radio link set and changing the present radio link set according to the radio link set message; operating a timer when the radio link set is changed and transmitting a radio link set completion (active set update complete) message to the RNC; and reverting the changed radio link set back to the previous backed-up radio link set when a reply signal is not received from the RNC even though the operation time of the timer expires.

Claims

1. A handover processing method for a mobile communication system, the method comprising:

requesting a radio link set to a radio network controller (RNC);

performing a backup of a present radio link set and changing the present radio link set, when the radio link set request is provided;

driving a first timer for counting a first time duration;

transmitting a radio link set completion message to the RNC;

driving a second timer for counting a second time duration;

checking whether a reply signal in response to the radio link set completion message is received;

checking whether the reply signal is received within the second time duration that is shorter than the first time duration;

retransmitting the radio link set completion message when the reply signal is not received within the second time duration; and

reverting the changed radio link set back to the previous backed-up radio link set when the reply signal is not received and both of the first and second periods of time have expired.

2. The method of claim 1, wherein the reverting step further includes:

checking whether the reply signal is received within the first time duration after the retransmitting step; and

reverting the radio link set to the backed-up radio link set when the reply signal is not received within the first time duration.

3. The method of claim 2, wherein the first time duration is the same as or greater than a sum of the second time duration and the retransmission time.

4. A handover processing method for a mobile communication system, the method comprising:

starting a handover procedure;

requesting a radio link set to a radio network controller (RNC) when the handover procedure starts;

performing a backup of a present radio link set and changing the present radio link set when the radio link set request is approved;

operating a first timer for counting a first period of time after the changing step;

transmitting a radio link set completion message to the RNC and waiting for a reply signal in response to the radio link set completion message;

operating a second timer to count a second period of time that is shorter than the first period of time;

retransmitting the radio link set completion message when the reply signal is not received in the second period of time;

reverting the changed radio link set back to the previous backed-up radio link set when the reply signal is not received and both of the first and second periods of time have expired; and

finishing the handover procedure.

5. The method of claim 4, wherein, if the reply signal is received before the first period of time expires, the finishing step is performed by bypassing the reverting step.

6. The method of claim 4, wherein the first timer is operated at a RRC (radio resource control) layer of a user equipment.

7. The method of claim 4, wherein the second timer is operated at a radio link control (RLC) layer of a user equipment.

8. The method of claim 4, wherein the first period of time is the same as or greater than a sum of the second period of time and the retransmission time.

9. A handover processing method for a mobile communication system, the method comprising:

requesting a radio link set to a radio network controller (RNC);

performing a backup of a present radio link set when the radio link set request is approved;

changing the present radio link set and operating a first timer to count a fist period of time;

transmitting a radio link set completion message to the RNC and operating a second timer to count a second period of time that is shorter than the first period of time;

checking whether a reply signal in response to the radio link set completion message is received from the RNC;

retransmitting the radio link set completion message when the reply signal is not received and the second time period has expired; and

reverting the changed radio link set back to the backed-up radio link set when the reply signal is not received and both of the first and second periods of time have expired.

10. The method of claim 9, wherein when the reply signal is received during the first or second time periods, the reverting step is bypassed and the handover processing is completed.

11. The method of claim 9, wherein the first timer is operated at a radio resource control (RRC) layer of a user device.

12. The method of claim 9, wherein the second timer is operated at a radio link control (RLC) layer of a user device.

13. The method of claim 9, wherein the first time period is the same as or greater than a sum of the second time period and the retransmission time.

14. A method of preventing abnormal handover operation, the method comprising:

modifying a current radio link set at a user device and then transmitting a completion message to a network device;

driving a first timer to count a first time duration;

checking whether a response signal in response to the completion message is received at the user device;

driving a second timer to count a second time duration;

checking whether the response signal is received within the second time duration that is shorter than the first time duration;

retransmitting at least once the completion message to the network device if no response signal is received during the second time duration; and

reverting the modified radio link set back to a backed-up radio link set when the reply signal is not received and both of the first and second periods of time have expired.

15. The method of claim 14, wherein, in the checking step, the response signal is an acknowledgment signal from the network device that acknowledges a receipt of the completion message.

16. The method of claim 15, wherein the network device is a radio network controller in a mobile communication system.

17. The method of claim 14, wherein, the checking step, the response signal is a confirmation signal that confirms a receipt of an acknowledgement signal from the network device, the acknowledgment signal acknowledging a receipt of the completion message.

18. The method of claim 14, wherein the first time duration is equal to or greater than a sum of the second time duration and a total retransmission time at the retransmitting step.

19. The method of claim 17, wherein the network device is a radio network controller in a mobile communication system.

20. The method of claim 14, wherein the first and second timers operate at a radio resource control layer of the user device.