WO2011053611A1

WO2011053611A1 - System and method for optimization of a wimax femto self-organized network for providing automatic neighbor relation

Info

Publication number: WO2011053611A1
Application number: PCT/US2010/054181
Authority: WO
Inventors: Jianquan Song; Tricci So; Wen Luo; Li Chu; Yangwei Tu; Junsheng Chu
Original assignee: Zte Usa Inc.
Priority date: 2009-10-28
Filing date: 2010-10-27
Publication date: 2011-05-05
Also published as: DE112010004199T5; GB2487026A; GB201207153D0; SE1250510A1; RU2012121891A; JP2013509816A

Abstract

Certain embodiments of the present invention provide a system and method for optimization of a WiMAX self-organized network (SON) for providing automatic neighbor relation (ANR) operation to obtain up-to-date Macro BS and WFAP neighbor information surrounding the WFAP. In one embodiment, a WFAP detects a change in neighbor base station information. Subsequently, the WFAP sends updated neighbor base station information to a SON server for validation. After receiving validation from the SON server, the WFAP updates its neighbor relation table with the updated neighbor base station information.

Description

S P E C I F I C A T I O N

SYSTEM AND METHOD FOR OPTIMIZATION OF A WIMAX FEMTO SELF- ORGANIZED NETWORK FOR PROVIDING AUTOMATIC NEIGHBOR RELATION

PRIORITY

[0001] Priority is claimed under 35 U.S.C. § 1 19 to U.S. Provisional Patent Application No. 61/255710, filed October 28, 2009, the disclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The field of the present invention is wireless communication and more specifically, automatic neighbor relation (ANR) of a self-organized network.

BACKGROUND

[0003] Cellular communication systems are typically arranged so that a plurality of base stations are strategically positioned to provide wireless

communication service over corresponding geographic areas. The area served by a base station is typically referred to as a cell. For various reasons it is desirable for the base station to have information regarding nearby base stations, one of these reasons being for facilitating handoffs as mobile stations travel between cells. A listing of such base stations is typically referred to as a neighbor relation table (NRT).

[0004] Generally, in cellular systems, system operators manually configure and manage neighbor lists based on the relative locations of base stations. This manual operation may be efficient for a network topology that hardly changes.

However, in a femtocell network, WiMAX Femtocell Access Points (WFAPs) can be frequently installed or uninstalled by a user, and not just by a system operator, making it difficult for system operators to effectively manage neighbor lists.

Therefore, automatic neighbor relation (ANR) schemes are desirable to lessen the system operator's burden of managing neighbor cells.

[0005] One problem of current ANR design is unreliable or out-of-date neighbor information. WFAP scanning may be limited to the WFAP's initialization. The WFAP may get neighbor base station information by scanning for nearby base stations or by obtaining a neighbor list from the system operator based on the

WFAP's location. However, the constructed neighbor list based upon WFAP initialization may not be reliable for many reasons. For example, a neighbor base station may not have any business relationship with a WFAP's Network Service Provider (NSP) (note too that the NSP ID of a WFAP may not be the same as a neighbor base station); a neighbor base station may not be operational (e.g., power on or off); or a neighbor base station may not be accessible by a mobile station.

[0006] Thus, for the purpose of handover operation, the identification of a given WFAP neighbor base station should not be selected blindly.' Rather, more reliable or up-to-date information should be provided to the WFAP to assist ANR scanning operations for the mobile station's neighbor base station selection.

SUMMARY OF THE INVENTION

[0007] The process of self-configuration is used during WFAP initialization. For self-configuration, the WFAP may get neighbor base station information based on the WFAP scanning or based on the WFAP's location. The process of self- optimization is used after WFAP initialization. For self-optimization, either the WFAP or a self-organized network (SON) server may detect that neighbor base station information has changed.

[0008] Certain embodiments of the present invention provide a system and method for optimization of a WiMAX self-organized network for providing automatic neighbor relation operation to obtain up-to-date macro base station information and WFAP neighbor base station information surrounding the WFAP.

[0009] According to certain embodiments of the invention, a WFAP detects a change in neighbor base station information. Subsequently, the WFAP sends updated neighbor base station information to a SON server for validation. After receiving validation from the SON server, the WFAP updates its neighbor relation table with the updated neighbor base station information.

[0010] According to certain embodiments of the invention, the SON server detects a change in neighbor base information. Subsequently, the SON server sends updated neighbor base station information to the WFAP.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In the drawings, wherein like reference numerals refer to similar components: [0012] Fig. 1 illustrates an embodiment of signaling for WFAP detection of a change of a neighbor base station's information.

[0013] Fig. 2 illustrates an embodiment of signaling for SON server detection of a change of a neighbor base station's information.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Referring now to Fig. 1 , when a WFAP detects that a neighboring base station's information has changed, it may be due to some mobile station (MS) reporting related message, such as MOB_SCN-REQ/REP or MOB_MSHO-REQ, or by some uncontrolled or unpredicted handover events.

[0015] WFAP detection of a change in a neighboring base station's information may be achieved using the following steps or signals. First, a WFAP detects a change in a neighboring base station's information. Second, the WFAP sends a Configuration Update Req to a SON server, the Configuration Update Req comprising the neighboring base station's updated information. Third, the SON server validates and/or checks this neighboring base station's updated information and may also trigger the update one or more other WFAPs' NRT. Fourth, the SON server sends a Configuration Update Rsp to the WFAP or WFAPs. Fifth, the WFAP or WFAPs update their NRT. Sixth, the WFAP or WFAPs send a Configuration Update Ack to the SON server.

[0016] Referring now to Fig. 2, when the SON server detects that a

neighboring base station's information has changed; it may do so due to some alarm information. For instance, a neighbor BS/WFAP may not be in operation (for example, backhaul offline); some configuration information, such as the installation of a new BS/WFAP; or removal of an existing base station (BS)/WFAP, or NRT checking (for example, if cell A is the neighbor of cell B, generally then cell B is also the neighbor of cell A).

[0017] SON server detection of a change in a neighbor's information may be achieved using the following steps or signals. First, a SON server detects a change in a neighbor's information. Second, the SON server sends a Configuration Update Req to one or more WFAPs, the Configuration Update Req comprising the neighbor's updated information. Third, the WFAP or WFAPs update their NRT.

Fourth, the WFAP(s) sends a Configuration Update Ack to the SON server. [0018] While embodiments of this invention have been shown and described, it will be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein. The invention, therefore, is not to be restricted except in the spirit of the following claims.

Claims

CLAIMS What is claimed is:

1 . A method of optimizing a WiMAX Femto Self-Organized Network, the method comprising:

detecting, by a WFAP, a change in neighbor base station information, wherein the WFAP maintains a neighbor relation table;

sending updated neighbor base station information to one or more SON servers; and

updating, in response to validation from at least one of the SON servers, the neighbor relation table based on the change in the updated neighbor base station information.

2. The method of claim 1 , wherein detecting the change in neighbor base station information includes detecting a mobile station reporting message.

3. The method of claim 1 , wherein detecting the change in neighbor base station information includes detecting uncontrolled or unpredicted handover events.

4. The method of claim 1 , further comprising:

updating one or more other neighbor relation tables, associated with one or more other WFAPs respectively, in response to validation from at least one of the SON servers.

5. The method of claim 1 , further comprising:

sending an acknowledgement message to at least one of the SON servers.

6. A method of optimizing a WiMAX Femto Self-Organized Network, the method comprising:

detecting, by at least one SON server, a change in neighbor base station information;

sending updated neighbor base station information to at least one WFAP. updating, by the WAFP, after receive the changing information about its neighbor base station from at least one SON server.

7. The method of claim 6, wherein detecting the change in neighbor base station information includes receiving a change indicator associated with a neighbor base station.

8. The method of claim 7, wherein the change indicator comprises information indicating one of installation or removal of at least one base station.

9. The method of claim 7, wherein the change indicator comprises information indicating failure of one base station which including backhaul offline.

10. The method of claim 7, wherein the change indicator comprises an alert associated with removal of at least one base station.

1 1. The method of claim 7, wherein the change indicator comprises a neighbor agreement between neighbor relation tables in two or more WFAPs.

12. A system for optimizing a WiMAX Femto Self-Organized Network, the system comprising:

at least one WFAP comprising a neighbor relation table, the at least one WFAP being configured to update the neighbor relation table in response to detecting a change in neighbor base station information.

13. The system of claim 12, wherein the at least one WFAP is further configured to validate the change in neighbor base station information with one or more SON servers.

14. The system of claim 12, wherein the at least one WFAP is further configured to send an acknowledgement message to at least one of the SON servers.

15. The system of claim 12, wherein the at least one WFAP is further configured to update one or more other neighbor relation tables associated with one or more other WFAPs respectively, in response to validation from at least one of the SON servers