Method for handoff to a femtocell in a wireless communication system, and server apparatus for the same

• US 20120129537A1
• Filed: 11/23/2011
• Published: 05/24/2012
• Est. Priority Date: 11/24/2010
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Wang, Hong, Liu, Guanghai, Ren, Junwei, Zhao, Tao
• Application Number:
  US13/373,652
• Publication Number:
  US 20120129537A1
• Time in Patent Office: Days
• US Class Current: 455/444
• CPC Class Codes: H04W 36/00835 Determination of neighbour cell lists
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells

Abstract

A method handsoff a terminal to a femtocell in a wireless communication system. The method includes, upon generation of a request for handoff to the femtocell, selecting, by a second server, at least one femtocells located within a predetermined distance from a source base station as candidate femtocells for the handoff, according to a request of a first server which functions as a femtocell gateway, receiving, by the first server, a response message comprising information of the candidate femtocells from the second server, sending, by the first server, a message requesting measurement of a reverse signal strength of a terminal under the handoff to the candidate femtocells, determining, by the first server, a destination femtocell for the handoff among the candidate femtocells based on the measurement result reported from the candidate femtocells, and executing a handoff procedure to the destination femtocell from the source base station.

Claims

1. A method for handoff to a femtocell in a wireless communication system, the method comprising:

upon generation of a request for handoff to the femtocell, selecting, by a second server, at least one femtocell located within a predetermined distance from a source base station as candidate femtocells for the handoff, according to a request of a first server which functions as a femtocell gateway;

receiving, by the first server, a response message comprising information of the candidate femtocells from the second server;

sending, by the first server, a message requesting measurement of reverse signal strength of a terminal under the handoff to the candidate femtocells;

determining, by the first server, a destination femtocell for the handoff among the candidate femtocells based on a measurement result reported from the candidate femtocells; and

executing a handoff procedure to the destination femtocell from the source base station.

2. The method of claim 1, wherein the request for the handoff to the femtocell is generated when the terminal detects that a strength of a pilot signal received from an adjacent femtocell exceeds a predetermined threshold value.

3. The method of claim 1, wherein when a plurality of candidate femtocells are present, the plurality of candidate femtocells use a same pseudo noise (PN) code.

4. The method of claim 1, wherein the information of the candidate femtocells comprises at least one of a cell identification (Cell_ID), a system identification (SID), a network identification (NID), and a femtocell equipment identification (FEID) of the candidate femtocells.

5. The method of claim 1, wherein the source base station is a macro base station.

6. The method of claim 1, wherein the source base station is a femto base station.

7. The method of claim 2 further comprising:

upon generation of the request for the handoff to the femtocell, receiving, by the first server, the pseudo noise (PN) code of the pilot signal through the source base station; and

selecting, by the second server which has received the PN code from the first server, the candidate femtocells using a same code as the PN code of the pilot signal.

8. The method of claim 1 further comprising:

establishing, by the second server, a database comprising information of other femtocell base stations located within a predetermined distance from each femtocell base station.

9. The method of claim 1, wherein the second sever is implemented within the first server.

10. The method of claim 1 further comprising:

managing, by a third server which communicates with the second server, information comprising location information, identification, and a pseudo noise (PN) code of each femtocell base station, in a database.

11. The method of claim 10, wherein the second server is implemented within the first server or the third server.

12. The method of claim 10, wherein the second server is implemented independently.

13. A method for handoff to a femtocell in a wireless communication system, the method comprising:

establishing, by a server which manages location related information of femtocells in the wireless communication system, a database comprising information of other femtocell base stations located within a predetermined distance from each femtocell base station;

upon receiving a request from a server which functions as a femtocell gateway according to generation of the request for the handoff to the femtocell from a source base station, querying the database and selecting at least one femtocell located within a predetermined distance from the source base station as candidate femtocells for the handoff; and

providing a response message comprising the information of the candidate femtocells to the server which functions as the femtocell gateway.

14. The method of claim 13, wherein the request for the handoff to the femtocell is generated when the terminal detects that a strength of a pilot signal received from an adjacent femtocell exceeds a predetermined threshold value.

15. The method of claim 13, wherein when a plurality of candidate femtocells are present, the plurality of candidate femtocells use a same pseudo noise (PN) code.

16. The method of claim 13, wherein the information of the candidate femtocells comprises at least one of a cell identification (Cell_ID), a system identification (SID), a network identification (NID), and a femtocell equipment identification (FEID) of the candidate femtocells.

17. The method of claim 13, wherein the source base station is a macro base station.

18. The method of claim 13, wherein the source base station is a femto base station.

19. A server apparatus for managing location related information of femtocells in a wireless communication system which supports handoff to a femtocell, the server apparatus comprising:

at least one network interface configured for data communication;

a database configured to store information of other femtocell base stations located within a predetermined distance from each femtocell base station; and

a controller configured to, upon receiving a request from a server which functions as a femtocell gateway according to generation of the request for the handoff to the femtocell from a source base station through the network interface, query the database, select at least one femtocell located within a predetermined distance from the source base station as candidate femtocells for the handoff, and provide a response message comprising the information of the candidate femtocells to the server which functions as the femtocell gateway through the network interface.

20. The server apparatus of claim 19, wherein the request for the handoff to the femtocell is generated when the terminal detects that a strength of a pilot signal received from an adjacent femtocell exceeds a predetermined threshold value.

21. The server apparatus of claim 19, wherein when a plurality of candidate femtocells are present, the plurality of candidate femtocells use a same pseudo noise (PN) code.

22. The server apparatus of claim 19, wherein the information of the candidate femtocells comprises at least one of a cell identification (Cell_ID), a system identification (SID), a network identification (NID), and a femtocell equipment identification (FEID) of the candidate femtocells.

23. The server apparatus of claim 19, wherein the source base station is a macro base station.

24. The server apparatus of claim 19, wherein the source base station is a femto base station.