Method for Handover Between Frequency Allocation in Broadband Wireless Access System

• US 20080039090A1
• Filed: 06/08/2005
• Published: 02/14/2008
• Est. Priority Date: 06/08/2004
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Jin, Yong Suk, Im, Bin
• Granted Patent: US 8,036,663 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/26 by agreed or negotiated communication parameters
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

A handover control method in a broadband wireless access system is disclosed. In a broadband wireless access system supporting multiple frequency allocations, in which a serving base station controls a handover, the present invention includes the steps of receiving from a mobile subscriber station a handover request message including an identifier of the mobile subscriber station, transmitting a handover request notification message including the identifier of the mobile subscriber station to a handover target base station, receiving a handover request notification response message including information for frequency allocation supportable by the target base station, and transmitting a handover response message including the information for the frequency allocation to the mobile subscriber station. Accordingly, in the broadband wireless access system supporting the multiple FA, the present invention enables the handover between FAs within one cell or between FAs in different cells.

Claims

1. In a broadband wireless access system supporting multiple frequency allocations, in which a serving base station controls a handover, a handover control method comprising the steps of:

receiving from a mobile subscriber station a handover request message including an identifier of the mobile subscriber station;

transmitting a handover request notification message including the identifier of the mobile subscriber station to a handover target base station;

receiving a handover request notification response message including information for frequency allocation supportable by the target base station; and

transmitting a handover response message including the information for the frequency allocation to the mobile subscriber station.

2. The handover control method of claim 1, wherein the information for the frequency allocation is a center frequency of an allocated frequency band.

3. The handover control method of claim 1, wherein the information for the frequency allocation is a frequency allocation identifier corresponding to an allocated frequency band.

4. The handover control method of claim 1, further comprising a step of transmitting to the target base station a handover confirmation message indicating that the mobile subscriber station will perform the handover with the supportable frequency allocation in response to the handover request notification response message.

5. The handover control method of claim 1, wherein the handover request notification message further includes connection parameters, capability, required bandwidth and information for quality of service.

6. The handover control method of claim 1, wherein the handover request notification response message further includes information for acknowledgement of the handover request notification message and information for whether a requested quality of service will be provided.

7. The handover control method of claim 1, further comprising a step of receiving from the mobile subscriber station a handover execution indication message including information for an action mode according to a handover execution type.

8. The handover control method of claim 7, wherein the action mode corresponds to one selected from the group consisting of a first case of the handover supported by backbone data exchange on network, a second case of the handover not by backbone data exchange on network, a third case that the handover directly takes place with a different FA within a cell of the serving base station, a fourth case of undergoing a network entry process for a new frequency allocation (FA) if the handover takes place with a different frequency allocation (FA) within a cell of the serving base station, and a fifth case of enabling the mobile subscriber station to perform fast handover in a manner that the serving base station previously allocates a non-contention ranging area necessary for the handover of the mobile subscriber station and the frequency allocation.

9. The handover control method of claim 7, further comprising a step of releasing a call for the mobile subscriber station after receiving the handover execution indication message.

10. The handover control method of claim 9, further comprising a step of transmitting a re-registration/release command message wherein the call of the mobile subscriber station is released based on information included in the re-registration/release command message.

11. The handover control method of claim 10, wherein the information included in the re-registration/release command message is an action code.

12. The handover control method of claim 11, wherein the action code indicates that the call shall be released while the mobile subscriber station maintains both a medium access control (MAC) address and a connection identifier (CID) of the mobile subscriber station.

13. The handover control method of claim 11, wherein the action code indicates that the call shall be released while the mobile subscriber station maintains a medium access control (MAC) address of the mobile subscriber station.

14. The handover control method of claim 11, wherein the action code indicates that a medium access control (MAC) address and a connection identifier (CID) of the mobile subscriber station are deleted to execute a network reentry to the handover target base station.

15. The handover control method of claim 1, wherein the handover target base station supports at least two frequency allocations.

16. The handover control method of claim 15, wherein the supportable frequency allocation corresponds to one selected from the group consisting of at least two frequency allocations supported by the handover target base station.

17. The handover control method of claim 1, further comprising a step of transmitting a network topology advertisement message including information for neighbor base stations to other mobile subscriber stations including the mobile subscriber station within an area of the serving base station.

18. In a broadband wireless access system, in which one base station supports multiple frequency allocation and controls a handover between frequency allocations, a handover control method comprising the steps of:

transmitting to a mobile subscriber station a handover request message requesting that the handover shall be executed with a specific frequency allocation provided by the base station;

receiving a handover execution indication message including information for a handover action mode from the mobile subscriber station; and

performing a network reentry procedure with the frequency allocation based on the action mode.

19. The handover control method of claim 18, wherein the action mode corresponds to one selected from the group consisting of a first case of the handover supported by backbone data exchange on network, a second case of the handover not by backbone data exchange on network, a third case that the handover directly takes place with a different FA within a cell of the serving base station, a fourth case of undergoing a network entry process for a new frequency allocation (FA) if the handover takes place with a different frequency allocation (FA) within a cell of the serving base station, and a fifth case of enabling the mobile subscriber station to perform fast handover in a manner that the serving base station previously allocates a non-contention ranging area necessary for the handover of the mobile subscriber station and the frequency allocation.

20. In a broadband wireless access system having a base station supporting multiple frequency allocations, in which a serving base station controls a handover, a handover control method comprising the steps of:

transmitting to a handover target base station a handover request notification message including an identifier of a mobile subscriber station which will perform the handover;

receiving from the handover target base station a handover notification response message including information for a frequency allocation supportable for the mobile subscriber station;

transmitting to the handover target base station a handover confirmation message notifying that the mobile subscriber station will perform the handover with the supportable frequency allocation; and

transmitting to the mobile subscriber station a handover request message requesting the handover with the frequency allocation of the handover target base station.

21. The handover control method of claim 20, further comprising a step of receiving from the mobile subscriber station a handover execution indication message notifying that the mobile subscriber station will perform the handover with the frequency allocation of the handover target base station.