METHOD OF BROADCASTING AND RECEIVING NEIGHBORING BASE STATION ADVERTISEMENT MESSAGE IN BROADBAND WIRELESS ACCESS SYSTEM, AND HANDOVER METHOD USING THE SAME

• US 20100280890A1
• Filed: 10/14/2008
• Published: 11/04/2010
• Est. Priority Date: 12/17/2007
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute, Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Yoon, Chul Sik, Park, Chul
• Granted Patent: US 8,615,243 B2
• Time in Patent Office: Days
• US Class Current: 705/14.4
• CPC Class Codes: G06Q 30/0241 Advertisements
• CPC Class Codes: H04W 36/0061 of neighbour cell information
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 72/00 Local resource management

Abstract

The present invention relates to a method of broadcasting and receiving a neighboring base station advertisement message in a wideband wireless access system and a handover method using the same. In the present invention, a base station broadcasts a neighboring base station advertisement message including information that indicates that frequency overlay is supported in neighboring base stations to terminals. The terminal confirms whether frequency overlay is supported in the neighboring base stations included in the neighboring base station advertisement message, and can perform handover to a frequency overlay supporting base station as a destination base station. According to the present invention, when a non-frequency overlay communication system and a frequency overlay communication system are mixed with each other, it is possible to ensure that a frequency overlay supporting terminal performs handover from a base station of a frequency overlay communication system to a base station of another frequency overlay communication system.

Claims

1. A method of broadcasting a neighbor base station advertisement message in a base station of a wideband wireless access system, the method comprising:

exchanging information with neighboring base stations to confirm whether frequency overlay is supported in each of the neighboring base stations;

generating a neighboring base station advertisement message that includes the information indicating whether frequency overlay is supported in each of the neighboring base stations; and

broadcasting the generated neighboring base station advertisement message to terminals that belong to a coverage area of the base station.

2. The method of claim 1, wherein the information indicating whether frequency overlay is supported is displayed by a type length value (TLV) parameter of the neighboring base station advertisement message.

3. The method of claim 1, wherein the base station uses a frequency band allocated to one of a plurality of applicable frequency assignments (FA) to broadcast the neighboring base station advertisement message.

4. The method of claim 1, wherein exchanging the information includes:

determining whether neighboring base stations exist;

when neighboring base stations exist, counting a number of neighboring base stations and confirming whether the corresponding neighboring base stations support frequency overlay;

when the corresponding neighboring base stations support frequency overlay, determining the corresponding neighboring base stations as frequency overlay supporting base stations;

repeating the process that includes the determining of whether neighboring base stations exist, the counting of the number of neighboring base stations and the confirming of whether the corresponding neighboring base stations support frequency overlay, and the determining of the corresponding neighboring base stations as the frequency overlay supporting base stations and confirming whether the neighboring base stations support frequency overlay, until the neighboring base stations do not exist; and

determining the counted number of neighboring base stations as the final number of neighboring base stations,

wherein, in the generating of the neighboring base station advertisement message, the final number of neighboring base stations is included in the neighboring base station advertisement message.

5. The method of claim 4, wherein, in the step of counting of the number of neighboring base stations, when it is determined whether the neighboring base stations are base stations that belong to a communication system supporting frequency overlay and it is determined that the neighboring base stations are the base stations that belong to the communication system, it is confirmed whether the neighboring base stations support frequency overlay.

6. A method of receiving a neighboring base station advertisement message in a terminal of a wideband wireless access system, the method comprising:

receiving the neighboring base station advertisement message broadcast from a base station, the neighboring base station advertisement message including information indicating whether frequency overlay is supported in neighboring base stations;

confirming whether frequency overlay is supported for each of the neighboring base stations that are included in the neighboring base station advertisement message; and

storing information that indicates whether frequency overlay is supported in each of the neighboring base stations.

7. The method of claim 6, wherein the base station uses a frequency band allocated to one of a plurality of applicable frequency assignments (FA) to receive the neighboring base station advertisement message.

8. The method of claim 6, wherein confirming whether frequency overlay is supported in each of the neighboring base stations includes:

determining whether neighboring base stations exist on the basis of a number of neighboring base stations included in the neighboring base station advertisement message;

when the neighboring base stations exist, confirming whether frequency overlay is supported in the corresponding neighboring base stations;

when the corresponding neighboring base stations support frequency overlay, determining the corresponding neighboring base stations as frequency overlay supporting base stations and storing information of the corresponding neighboring base stations; and

repeating the process that includes the determining of whether the neighboring base stations exist, the confirming of whether frequency overlay is supported in the corresponding neighboring base stations, and the determining of the corresponding neighboring base stations as frequency overlay supporting base stations and the storing of information of the corresponding neighboring base stations and confirming whether frequency overlay is supported in each of the neighboring base stations, until the neighboring base stations do not exist.

9. A handover method in which a base station of a wideband wireless access system performs handover, the handover method comprising:

broadcasting a neighboring base station advertisement message including information of neighboring base stations, the neighboring base station advertisement message including information indicating whether frequency overlay is supported in each of the neighboring base stations;

receiving a list of candidate base stations where handover is possible from a terminal, the candidate base stations being selected on the basis of the information included in the broadcast neighboring base station advertisement message and indicating whether frequency overlay is supported;

transmitting handover information of the terminal to the candidate base stations;

selecting a recommended base station from among the candidate base stations and transmitting information of the recommended base station to the terminal; and

receiving a handover instruction from the terminal.

10. The handover method of claim 9, wherein, when the base station and the terminal support frequency overlay, the base station and the terminal transmit information for handover through one of the plurality of frequency assignments (FAs).

11. The handover method of claim 9, wherein when the terminal supports frequency overlay, the handover information transmitted to the candidate base stations includes information indicating whether the terminal can perform communication through the plurality of FAs that comprise non-adjacent frequency bands.

12. A handover method in which a terminal of a wideband wireless access system performs handover, the method comprising:

receiving a neighboring base station advertisement message that is broadcast from a base station, the neighboring base station advertisement message including a list of neighboring base stations and information indicating whether frequency overlay is supported in each of the neighboring base stations;

when handover is performed, selecting candidate base stations for the handover from among the neighboring base stations on the basis of the information indicating whether frequency overlay is supported;

transmitting a list of the selected candidate base stations to the base station;

selecting one destination base station from among a list of recommended base stations received from the base station and instructing the base station to perform handover; and

performing handover to the destination base station.

13. The handover method of claim 12, wherein the candidate base stations are selected from among the neighboring base stations supporting frequency overlay when the terminal supports frequency overlay.

14. The handover method of claim 13, wherein, when the terminal and the base station support frequency overlay, the terminal and the base station transmit information for handover through one of a plurality of frequency assignments (FAs).

15. The handover method of claim 14, wherein the handover to the destination base station is performed through one of the plurality of FAs, the method further comprising performing a subsequent handover through the other FAs when the handover is completed.

16. The handover method of claim 15, wherein the destination base station receives from the base station information indicating whether the terminal can perform communication through the plurality of FAs that comprise non-adjacent frequency bands.

17. The handover method of claim 12, wherein the list of the selected candidate base stations is included in a handover request message to the base station.

18. The handover method of claim 17, wherein the list of recommended base stations received from the base station is included in a handover response message.

19. The handover method of claim 17, wherein the handover request message transmitted to the base station further includes information indicating whether the terminal can perform communication through the plurality of FAs that comprise non-adjacent frequency bands.

20. The handover method of claim 12, wherein selecting candidate base stations for the handover from among the neighboring base stations comprises performing a scanning process of measuring a quality of downlink signals received from the neighboring base stations.