METHOD OF CHANGING FREQUENCY ASSIGNMENT STATUS IN BROADBAND WIRELESS ACCESS SYSTEM

• US 20100271941A1
• Filed: 10/14/2008
• Published: 10/28/2010
• Est. Priority Date: 12/18/2007
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute, Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Hyun, Lim, Kwang Jae, Yoon, Chul Sik, Park, Chul
• Granted Patent: US 8,681,732 B2
• Time in Patent Office: Days
• US Class Current: 370/230
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 36/22 for handling the traffic
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA

Abstract

The present invention relates to a method of changing a frequency assignment (FA) status in an improved broadband wireless access system where terminals and base stations can communicate with each other by using a plurality of FAs. In the present invention, the base station changes the status of one of secondary FA into the status of the pFA in order to adjust a load of the primary FA, and communicates with the terminal through the pFA of which status is changed. For this purpose, the base station transmits a MAP information element (IE), which requests the change of the status of the pFA, to the terminal. The MAP IE includes an action code that requests the change of the status of the pFA, and a bit map representing an FA of which status is to be changed. When a response, which represents the completion of the change of the status of the pFA of the base station, is received from the terminal, the base station changes the status of the pFA and communicates with the pFA of the terminal through a new pFA. The status of a previous pFA between the base station and the terminal is changed into the status of the sFA, and the status of one previous sFA between the base station and the terminal is changed into the status of the pFA, so that communication is performed through new FAs. According to the present invention, since the base station can change the status of a specific terminal and FAs in use according to need, it is possible to adjust loads between the FAs. Further, the base station can change the statuses of the FAs in use while continuously maintaining the access of a specific terminal.

Claims

1. A method of changing a frequency assignment (FA) status in a base station of a broadband wireless access system, the method comprising:

deciding an FA of which status is to be changed;

transmitting a status change request of the decided FA to a terminal; and

receiving a completion response of the status change request of the FA from the terminal.

2. The method of claim 1, wherein the deciding of the FA includes:

determining whether a load of a primary FA, among a plurality of FAs communicating with the terminal, for transmitting main control signals and data traffic needs to be adjusted by the base station; and

deciding a secondary FA of which status is to be changed into the state of the primary FA, from secondary FAs (herein, the secondary FAs are the rest of the FAs except for the primary FA) if it is determined that the load of the primary FA does need to be adjusted.

3. The method of claim 2, wherein the transmitting of the status change request includes:

selecting terminals, of which statuses are changed, among terminals that communicate with the primary and secondary FAs;

generating messages for requesting the selected terminals to change the status of the primary FA; and

transmitting the generated messages to the selected terminals.

4. The method of claim 3, further comprising

after the receiving of the completion response,

communicating with the terminals through the FAs of which statuses are completely changed,

wherein the communicating with the terminals includes:

changing the status of the secondary FA, which is decided in the deciding of the secondary FA, into the status of the primary FA;

transmitting control signals and data traffic to the terminals through the primary FA of which status is changed;

changing the status of the existing primary FA, which has communicated with the terminals, into the state of the secondary FA; and

transmitting data traffic to the terminals through the secondary FA of which status is changed.

5. The method of claim 1, wherein the broadband wireless access system is a frequency overlay communication system for providing a frequency overlay function that makes the base stations communicate with the terminals through the plurality of FAs.

6. The method of claim 2, wherein the message is a MAP that is transmitted to the terminal by the base station, and is an information element (hereinafter, referred to as a “

MAP IE”

) where the information about the status change is included in the MAP and transmitted.

7. The method of claim 6, wherein the MAP IE is an anchor base station switch information element that is a MAP IE included in a UL MAP transmitted to the terminal by the base station in order to perform the high-speed switching of the base station, or a newly defined MAP IE that is used to request the change of the status of the FA.

8. The method of claim 7, wherein the information about the status change included in the MAP IE includes:

an action code representing a request that makes a terminal receiving the MAP IE change the status of the FA; and

an FA change bit map representing an FA of which status is changed by the terminal.

9. The method of claim 8, wherein:

the FA change bit map includes;

an action time field representing time required until the status of the FA is changed;

an index field representing an FA of which status is to be changed; and

an FA related bit map that represents all of the FAs used by the base stations and FAs communicating with the terminals.

10. The method of claim 9, wherein a value of the index field is a value that represents one of bits of the FA related bit map, and

an FA corresponding to the bit represented by the value of the index field is an FA of which status should be changed.

11. The method of claim 3, wherein the messages transmitted to the selected terminals are transmitted to the primary FAs of the selected terminals through the primary FA of the base station.

12. The method of claim 11, wherein responses to the messages transmitted to the primary FAs of the selected terminals are received through the secondary FAs of the base stations of which statuses are changed.

13. The method of claim 1, wherein the status change request of the FA enables or disables the decided FA.

14. A method of changing an FA status in a terminal of a broadband wireless access system, the method comprising:

receiving a status change request of an FA from a base station;

confirming an FA of which status is to be changed in the base station;

changing the status of the FA; and

transmitting a response, which represents the completion of the change of the FA, to the base station.

15. The method of claim 14, wherein in the receiving of the status change request, the terminal receives the status change request of the FA through a primary FA, among a plurality of FAs communicating with the base station, for transmitting main control signals and data traffic.

16. The method of claim 14, wherein in the receiving of the status change request, the status change request of the FA is received through a MAP transmitted from the base station, and information about an FA of which status is changed is included in an information element that is included in the MAP and transmitted.

17. The method of claim 15, wherein in the confirming of the FA, the primary FA of the terminal confirms the change of the status of the primary FA of the base station through the status change request of the FA, and secondary FAs, of which status is changed into the status of the primary FA, of the base station (herein, the secondary FAs are the rest of the FAs except for the primary FA) among the plurality of FAs of the base station.

18. The method of claim 17, wherein in the changing of the status of the FA, the primary FA of the terminal changes the status of the secondary FA, of which status is to be changed into the status of the primary FA in the confirming of the FA, of the base station into the status of the primary FA of the base station, and in the transmitting of the response, a response representing the completion of the change of the status of the FA is transmitted to the secondary FA of the base station.

19. The method of claim 17, further comprising:

after the transmitting of the response,

communicating with the FA, of which status is completely changed, of the base station,

wherein in the communicating with the FA, the primary FA of the terminal transmits control signals and data traffic to the secondary FA of the base station.

20. The method of claim 19, further comprising:

after the communicating with the FA,

changing the status of the primary FA of the base station into the status of the secondary FA of the base station by the secondary FAs of the terminals (herein, the secondary FAs of the terminals are the rest of the FAs except for the primary FA), and transmitting data traffic to the secondary FA of which status is changed.

21. The method of claim 14, wherein:

the change of the status of the FA is the status change that enables or disables the FA.