System, method, and apparatus for cell searching in a next generation overlay of a preexisting network

• US 6,597,911 B1
• Filed: 05/28/1999
• Issued: 07/22/2003
• Est. Priority Date: 05/28/1999
• Status: Expired due to Term

• Current Assignee: Petroleum Geo-Services ASA (PGS ASA), Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Kransmo, Jan
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): Orgad, Edan
• Application Number:
  US09/322,365
• Time in Patent Office: 1,516 Days
• Field of Search: 455/436-440, 455/442-444, 455/403, 455/448, 455/449, 370/320, 370/324, 370/331, 370/441
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0061 of neighbour cell information
• CPC Class Codes: H04W 36/0066 of control information between different types of networks in order to establish a new radio link in the target network

Abstract

A system, method, and apparatus for performing a handover for mobile station are presented. Where a mobile station in a preexisting cellular network approaches the service area of a next generation network, the serving base station transmits a cell neighbor list to the mobile station. The cell neighbor list includes nearby base stations within the preexisting cellular network as well as the next generation network. The mobile station can then measure the signal strength on the handover measurement channels of the cells in the next generation network. A method and associated apparatus for measuring the handover measurement channels of base stations in a next generation network using Code Division Multiple Access (CDMA), are also presented.

Claims

1. In a mobile telecommunications system comprising a preexisting cellular network associated with a first service location area and a first plurality of cells, each of said first plurality of cells being served by a particular one of a first plurality of base stations, and a next generation cellular network associated with a second service location area and a second plurality of cells, each of said second plurality of cells being served by a particular one of a second plurality of base stations, said second service location area partially overlapping said first service location area, a method for performing a handover for a mobile station served by a particular one of said first plurality of base stations, said method comprising the steps of:

receiving a cell neighbor list from said particular one of said first plurality of base stations serving said mobile station at said mobile station upon entering said second service location area, said cell neighbor list including an indicator identifying at least one of said second plurality of base stations; and

measuring the signal strength of a handover measurement channel associated with said at least one of said second plurality of base stations identified by said indicator by said mobile station.

2. The method of claim 1, wherein said preexisting cellular network comprises a Global System for Mobile Communications network.

3. The method of claim 1, wherein said preexisting cellular network comprises a Digital American Mobile Phone Service network.

4. The method of claim 1, wherein said next generation network comprises a code division multiple access network.

5. The method of claim 4, wherein said indicator includes at least one parameter selected from a group consisting of:

an identification associated with said next generation network;

an identification associated with said at least one of said second plurality of cells;

a broadband frequency associated with said next generation network;

a primary synchronization channel associated with said next generation network;

a secondary synchronization channel associated with said at least one of said second plurality of cells; and

a pilot code associated with said at least one of said second plurality of cells.

6. The method of claim 4, wherein said step of measuring further comprises the step of:

determining a scrambling code used by a handover measurement channel associated with said at least one of said second plurality of cells.

7. The method of claim 6, wherein said step of measuring further comprises the steps of:

acquiring slot synchronization with said at least one of said second plurality of cells; and

identifying a code group associated with said at least one of said second plurality of cells.

8. A preexisting cellular network for handing off a mobile station served by said preexisting cellular network to a recipient cell in a next generation cellular network, said next generation cellular network having a service location area partially overlapping a service location area of said preexisting cellular network, said preexisting cellular network comprising:

a base station serving said mobile station, said base station transmitting a cell neighbor list to said mobile station upon a determination that said mobile station is entering said service location area of said next generation cellular network, said cell neighbor list including an indicator identifying said recipient cell in said next generation cellular network; and

a base station controller for receiving measurement results for said recipient cell.

9. The preexisting cellular network of claim 8, wherein said preexisting cellular network further comprises a Global System for Mobile Communications.

10. The preexisting cellular network of claim 8, wherein said preexisting cellular network further comprises an American Mobile Phone Services network.

11. The preexisting cellular network of claim 8, wherein said next generation network comprises a code division multiple access network.

12. The preexisting cellular network of claim 11, wherein said indicator is selected from a group consisting of:

an identification associated with said next generation network;

an identification associated with said recipient cell;

a broadband frequency associated with said next generation network;

a primary synchronization channel associated with said next generation network;

a secondary synchronization channel associated with said recipient cell; and

a pilot code associated with said recipient cell.

13. A mobile station operable in a preexisting cellular network in accordance with a first mode, and operable in a next generation network in accordance with a second mode, said next generation network having a service location area partially overlapping a service location area of said preexisting cellular network, said mobile station comprising:

a filter for acquiring slot synchronization with a base station forming a portion of said next generation network upon entering said service location area of said next generation network, said portion including a plurality of cells;

code identification means for identifying a code group associated with at least one of said plurality of cells; and

code determining means for determining a scrambling code used by a handover measurement channel associated with said at least one of said plurality of cells.