Method for performing handover in broadband wireless access system

• US 20050288022A1
• Filed: 05/06/2005
• Published: 12/29/2005
• Est. Priority Date: 05/07/2004
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Yong Ho, Kwak, Yong Won, Cho, Ki Hyoung, Kim, Beum Joon, Ryu, Ki-Seon
• Granted Patent: US 7,986,949 B2
• Time in Patent Office: Days
• US Class Current: 455/439
• CPC Class Codes: H04W 36/0033 with transfer of context information
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 76/28 Discontinuous transmission [DTX]; Discontinuous reception [DRX]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method of entering sleep mode in a mobile subscriber station in performing handover from a first base station (BS) to a second BS is disclosed. More specifically, the method includes entering sleep mode in the first base station and transmitting from the first base station sleep mode information in the first base station during handover, while receiving from a second base station sleep mode entry information in the second base station. The method further includes entering sleep mode based on the information the sleep mode entry information received from the second base station.

Claims

1. A method of entering sleep mode in a mobile subscriber station (MSS) in performing handover from a first base station (BS) to a second BS, the method comprising:

entering sleep mode in the first base station;

transmitting from the first base station sleep mode information in the first base station during handover;

receiving from a second base station sleep mode entry information in the second base station; and

entering sleep mode based on the information the sleep mode entry information received from the second base station.

2. The method of claim 1, wherein the sleep mode information received from the second base station is received after handover.

3. The method of claim 1, wherein the sleep mode entry information in the first base station is transmitted via a ranging request message.

4. The method of claim 1, wherein the sleep mode information received from the second BS is received via a ranging response message.

5. The method of claim 1, wherein the sleep mode entry information in the second base station is received via a sleep response message.

6. The method of claim 3, wherein the sleep response message is an unsolicited sleep response message.

7. The method of claim 3, wherein the sleep mode entry information is transmitted using a power saving class parameter included in the ranging request message.

8. The method of claim 5, wherein the sleep mode entry information is transmitted using a power saving class parameter included in the sleep response message.

9. The method of claim 7, wherein the power saving class parameter includes three power saving class parameter types which represent transmission methods, a first power saving class parameter type includes a Non-Real-Time Variable Rate (NRT-VR) in which transmission rate varies, a second power saving class parameter type includes a Voice over Internet Protocol (VoIP) or a Real-Time Variable Rate (RT-VR), a third power saving class parameter type includes a periodic transmission of a control message to the MSS in sleep mode or a data which is multicast transmitted.

10. The method of claim 9, wherein a class parameter further includes an initial sleep window and a final sleep window parameters if the power saving class parameter type is set to the first power saving class parameter type.

11. The method of claim 10, wherein the initial sleep window parameter comprises 8 bits.

12. The method of claim 11, wherein a size of the initial sleep window parameter does not exceed 2⁸-1 frames if an initial sleep window field is set to “

1111111.”

13. The method of claim 9, wherein a class parameter further includes an initial sleep window parameter if the power saving class parameter type is set to the second power saving class parameter type.

14. The method of claim 9, wherein a class parameter further includes a final sleep window parameter if the power saving class parameter type is set to the third power saving class parameter type.

15. The method of claim 10, wherein the final sleep window parameter includes a final sleep window base and a final window exponent to calculate a size of the final sleep window, the size of the final sleep window is calculated by using Final Sleep Window=Final Sleep Window Base*2^{Final Window Exponent}.

16. The method of claim 8, wherein the power saving class parameter includes three power saving class parameter types which represent transmission methods, a first power saving class parameter type includes a Non-Real-Time Variable Rate (NRT-VR) in which transmission rate varies, a second power saving class parameter type includes a Voice over Internet Protocol (VoIP) or a Real-Time Variable Rate (RT-VR), a third power saving class parameter type includes a periodic transmission of a control message to the MSS in sleep mode or a data which is multicast transmitted.

17. The method of claim 16, wherein a class parameter further includes an initial sleep window and a final sleep window parameters if the power saving class parameter type is set to the first power saving class parameter type.

18. The method of claim 17, wherein the initial sleep window parameter comprises 8 bits.

19. The method of claim 18, wherein a size of the initial sleep window parameter does not exceed 2⁸-1 frames if an initial sleep window field is set to “

1111111.”

20. The method of claim 16, wherein a class parameter further includes an initial sleep window parameter if the power saving class parameter type is set to the second power saving class parameter type.

21. The method of claim 16, wherein a class parameter further includes a final sleep window parameter if the power saving class parameter type is set to the third power saving class parameter type.

22. The method of claim 17, wherein the final sleep window parameter includes a final sleep window base and a final window exponent to calculate a size of the final sleep window, the size of the final sleep window is calculated by using Final Sleep Window=Final Sleep Window Base*2^{Final Window Exponent}.

23. A method for a mobile subscriber station (MSS) entering sleep mode, the method comprising:

entering a first sleep mode in a first base station (BS);

performing handover from the first BS to a second BS;

transmitting from the first BS information on a last sleep interval of sleep mode to the second BS after completing handover; and

receiving from the second BS information on an initial sleep interval of a second sleep mode.

24. The method of claim 23, wherein a duration of a last sleep interval of the first sleep mode is same as a duration of an initial sleep interval of the second sleep mode.

25. The method of claim 23, wherein the information on the last sleep interval is transmitted via a sleep request message.

26. The method of claim 23, wherein the information of the initial sleep interval is transmitted via a sleep response message.

27. A method of controlling entry to sleep mode in a mobile subscriber station (MSS) in a second base station (BS) when a first BS performs handover to the second BS, the method comprising:

receiving sleep mode entry information in the first BS from the MSS during handover; and

transmitting sleep mode entry information in the second BS based on the sleep mode entry information in the first BS after termination of handover.

28. The method of claim 27, wherein the sleep mode entry information in the first BS is received via a ranging request message.

29. The method of claim 28, wherein the sleep mode entry information in the second BS is transmitted via an unsolicited sleep request message.