INTER-PLMN HANDOVER IN A SHARED RADIO NETWORK

• US 20110065436A1
• Filed: 05/22/2008
• Published: 03/17/2011
• Est. Priority Date: 05/22/2008
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Ehrenholm, Bo, Svedevall, Sofia, Gustavsson, Pär, Walldeen, Thomas
• Granted Patent: US 8,731,557 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• 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
• CPC Class Codes: H04W 36/22 for handling the traffic
• CPC Class Codes: H04W 88/10 adapted for operation in multiple networks, e.g. multi-mode access points

Abstract

Handover control in a control node, said control node controlling allocation of radio resources in a first set of cells belonging to at least two different Public Land Mobile Networks, said first set of cells including at least a first subset of cells belonging to a first Public Land Mobile Network and a second subset of cells belonging to a second Public Land Mobile Network. Traffic load exceeding a predefined level is detected (504) in a first cell belonging to the first subset of cells. In response to said detecting, connections in the first cell are evaluated (507, 509) to find one or more connections which could be supported by radio resources in one or more cells in the second subset of cells having capacity for handling additional traffic load. Handover is ordered (506, 510) of at least one of said one or more connections to said one or more cells in the second subset of cells.

Claims

1. A method of handover control in a control node, said control node controlling allocation of radio resources in a first set of cells belonging to at least two different Public Land Mobile Networks, said first set of cells including at least a first subset of cells belonging to a first Public Land Mobile Network and a second subset of cells belonging to a second Public Land Mobile Network, wherein the method comprises:

detecting traffic load exceeding a predefined level in a first cell belonging to the first subset of cells;

evaluating, in response to said detecting the traffic load exceeding the predefined level, connections in the first cell to find one or more connections which could be supported by radio resources in one or more cells in the second subset of cells having capacity for handling additional traffic load; and

ordering handover of at least one of said one or more connections to said one or more cells in the second subset of cells.

2. A method according to claim 1, wherein ordering handover of said at least one connection to said one or more cells in the second subset of cells is performed without prior notification to a core network node operably connected to the control node that it would be desirable to perform said handover.

3. A method according to claim 1, wherein in response to the control node detecting a new connection, the control node registers in memory initial detection data associated with the new connection and indicative of the Public Land Mobile Network to which the cell belongs in which the new connection was initially detected by the control node, said data being maintained in memory for as long as the connection remains supported by resources in any one of the cells in the first set of cells.

4. A method according to claim 3, wherein said new connection is detected in response to either initial connection setup in a cell in the first set of cells or handover to a cell in the first set of cells from a cell under the control of a second control node.

5. A method according to claim 3, wherein said initial detection data include at least one of:

Public Land Mobile Network identity of the cell in which the new connection was detected;

identity of the cell in which the new connection was detected; and

identity of a core network node uniquely associated with the Public Land Mobile Network to which the cell in which the new connection was detected belongs.

6. A method according to claim 3, wherein said evaluating is performed according to a predetermined rule which discriminates between connections whose initial detection data indicate the first Public Land Mobile Network and connections whose initial detection data indicate the second Public Land Mobile Network.

7. A method according to claim 6, wherein said predetermined rule causes said evaluating to prioritize finding connections whose initial detection data indicate the second Public Land Mobile Network over connections whose initial detection data indicate the first Public Land Mobile Network.

8. A method according to claim 3, wherein in response to detecting a need for handover of a first connection from a serving cell in the first set of cells to a cell under the control of another control node,

checking if the serving cell belongs to the Public Land Mobile Network indicated by the initial detection data associated with the first connection and,

responsive to the serving cell not belonging to the Public Land Mobile Network indicated by the initial detection data, ordering a handover of the first connection to a cell in the first set of cells which belongs to the Public Land Mobile Network indicated by the initial detection data associated with the first connection.

9. A method according to any claim 3, wherein in response to detecting a need for handover of a first connection from a serving cell in the first set of cells to a cell under the control of another control node,

checking if the serving cell belongs to the Public Land Mobile Network indicated by the initial detection data associated with the first connection and, responsive to the serving cell not belonging to the Public Land Mobile Network indicated by the initial detection data,

initiating a handover to the cell under the control of another control node, while indicating as serving cell a cell belonging to the Public Land Mobile Network indicated by the initial detection data associated with the first connection whose radio coverage area essentially corresponds to the radio coverage area of the serving cell.

18. A computer program embodied on a computer-readable medium and executable by digital data processing circuitry to perform a method according to claim 1.

10. A control node that controls allocation of radio resources in a first set of cells belonging to at least two different Public Land Mobile Networks, said first set of cells including at least a first subset of cells belonging to a first Public Land Mobile Network and a second subset of cells belonging to a second Public Land Mobile Network, the control node comprising:

detecting circuitry that detects when traffic load exceeds a predefined level in a first cell belonging to the first subset of cells;

evaluating circuitry that evaluates, responsive to the traffic load exceeding the predefined level, connections in the first cell to find one or more connections which could be supported by radio resources in one or more cells in the second subset of cells having capacity for handling additional traffic load; and

handover circuitry that orders handover of at least one of said one or more connections to said one or more cells in the second set of cells.

11. A control node according to claim 10, wherein said handover circuitry is adapted to order handover of said at least one connection to said one or more cells in the second subset of cells without prior notification to a core network node operable connected to the control node that it would be desirable to perform said handover.

12. A control node according to any one of claim 10, wherein said control node further comprises:

connection detection circuitry adapted to respond to detection of a new connection by registering in memory initial detection data associated with the new connection and indicative of the Public Land Mobile Network to which the cell belongs in which the new connection was initially detected by the control node, said data being maintained in memory for as long as the connection remains supported by resources in any one of the cells in the first set of cells.

13. A control node according to claim 12, wherein said new connection is detected in response to either initial connection setup in a cell in the first set of cells or handover to a cell in the first set of cells from a cell under the control of a second control node.

14. A control node according to any claim 12, wherein said initial detection data include at least one of:

Public Land Mobile Network identity of the cell in which the new connection was detected;

identity of the cell in which the new connection was detected; and

identity of a core network node uniquely associated with the Public Land Mobile Network to which the cell in which the new connection was detected belongs.

15. A control node according to claim 12, wherein said evaluating circuitry is arranged for evaluating according to a predetermined rule which discriminates between connections whose initial detection data indicate the first Public Land Mobile Network and connections whose initial detection data indicate the second Public Land Mobile Network.

16. A control node according to claim 15, wherein said predetermined rule causes said evaluating circuitry to prioritize finding connections whose initial detection data indicate the second Public Land Mobile Network over connections whose initial detection data indicate the first Public Land Mobile Network.

17. A control node according to claim 10, wherein the evaluating circuitry is further arranged for evaluating, in response to the traffic load exceeding the predefined level, connections in the first cell to find one or more connections which could be supported by radio resources in one or more other cells in the first subset of cells having capacity for handling additional traffic load, and the handover circuitry is further arranged for ordering handover of at least one of said one or more connections to said one or more other cells in the first subset of cells.