Control node handover in radio access network

• US 20020072363A1
• Filed: 12/11/2000
• Published: 06/13/2002
• Est. Priority Date: 12/11/2000
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Riihinen, Wesa, Soderberg, Johan
• Granted Patent: US 6,944,462 B2
• Time in Patent Office: Days
• US Class Current: 455/432.1
• CPC Class Codes: H04W 36/12 Reselecting a serving backbone network switching or routing node
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection

Abstract

A telecommunications system (10) has a radio access network comprising plural control nodes (26) and inter-control node links (Iur) for connecting the plural control nodes. A handover selection function (200) makes a selection regarding which of plural connections handled by the radio access network should have control thereof moved from a first control node (e.g., current SRNC) to another of the plural control nodes (e.g., target SRNC) to alleviate congestion on an overloaded one of the inter-control node links. The selection includes a determination of a cost for each of the connections carried by the overloaded link. The cost of each of the connections carried by the overloaded link is a product of a number of inter-control links involved in the connection and an inter-control link bandwidth required by the connection. The handover selection function particularly determines a most costly one of the connections carried by the overloaded link, and further determines a target one of the plural control nodes to which the control of the most costly connection can be handed over. In accordance with one aspect of the invention, the target control node is a control node involved in the candidate connection which is farthest from the first control node (e.g., current SRNC node).

Claims

1. A telecommunications system having a radio access network comprising:

plural control nodes;

inter-control node links for connecting the plural control nodes;

a handover selection unit which makes a selection regarding which of plural connections handled by the radio access network should have control thereof moved from a first control node to another of the plural control nodes to alleviate congestion on an overloaded one of the inter-control node links, the selection including a determination of a cost for each of the connections carried by the overloaded link.

2. The system of claim 1, wherein the cost for each of the connections carried by the overloaded link depends on (1) a number of inter-control links involved in the connection, and (2) an inter-control link bandwidth required by the connection.

3. The system of claim 1, wherein the cost for each of the connections carried by the overloaded link is a product of a number of inter-control links involved in the connection and an inter-control link bandwidth required by the connection.

4. The system of claim 1, wherein the handover selection unit is situated at one of the plural control nodes.

5. The system of claim 1, wherein the handover selection unit is situated at core network node.

6. The system of claim 1, wherein the selection includes a determination of a most costly one of the connections carried by the overloaded link, and wherein the most costly one of the connections carried by the overloaded link becomes a candidate connection for handover.

7. The system of claim 6, wherein the handover selection unit further determines a target one of the plural control nodes to which the control of the candidate connection can be handed over, the target control node being a control node involved in the candidate connection which is farthest from the first control node.

8. The system of claim 1, wherein the handover selection unit makes the selection when an attempt is made to add a new connection or new leg of a connection to the radio access network, and wherein when hand over of control of the candidate connection to the target control node is unacceptable to the network, the handover selection unit decreases a number of the inter-control node links which can be utilized by the new connection or new leg of the connection before reattempting its selection.

9. A method of operating telecommunications system having a radio access network, the radio access network having plural control nodes and inter-control node links for connecting the plural control nodes, wherein the method comprises selecting which of plural connections handled by the radio access network should have control thereof moved from a first control node to another of the plural control nodes to alleviate congestion on an overloaded one of the inter-control node links, the selecting including a determining a cost for each of the connections carried by the overloaded link.

10. The method of claim 9, further comprising determining the cost for each of the connections carried by the overloaded link as a function of (1) a number of inter-control links involved in the connection, and (2) an inter-control link bandwidth required by the connection.

11. The method of claim 9, determining the cost for each of the connections carried by the overloaded link by multiplying a number of inter-control links involved in the connection and an inter-control link bandwidth required by the connection.

12. The method of claim 9, wherein the selecting includes determining a most costly one of the connections carried by the overloaded link, and wherein the most costly one of the connections carried by the overloaded link becomes a candidate connection for handover.

13. The method of claim 12, further comprising determining a target one of the plural control nodes to which the control of the candidate connection can be handed over, the target control node being a control node involved in the candidate connection which is farthest from the first control node.

14. The method of claim 9, wherein the selecting step is performed when an attempt is made to add a new connection or new leg of a connection to the radio access network, and wherein when hand over of control of the candidate connection to the target control node is unacceptable to the network, a number of the inter-control node links which can be utilized by the new connection or new leg of the connection is decreased before reattempting the selecting step.

16. The function of claim 15, wherein the function is performed at one of the plural control nodes of the radio access network.

17. The function of claim 15, wherein the function is performed at a core network node.

18. The function of claim 15, wherein the cost for each of the connections carried by the overloaded link depends on (1) a number of inter-control links involved in the connection, and (2) an inter-control link bandwidth required by the connection.

19. The function of claim 15, wherein the cost for each of the connections carried by the overloaded link is a product of a number of inter-control links involved in the connection and an inter-control link bandwidth required by the connection.

20. The function of claim 15, wherein the selection includes a determination of a most costly one of the connections carried by the overloaded link, and wherein the most costly one of the connections carried by the overloaded link becomes a candidate connection for handover.

21. The function of claim 20, wherein the handover selection function further determines a target one of the plural control nodes to which the control of the candidate connection can be handed over, the target control node being a control node involved in the candidate connection which is farthest from the first control node.

22. The function of claim 15, wherein the handover selection function makes the selection when an attempt is made to add a new connection or new leg of a connection to the radio access network, and wherein when hand over of control of the candidate connection to the target control node is unacceptable to the network, the handover selection function decreases a number of the inter-control node links which can be utilized by the new connection or new leg of the connection before reattempting its selection.

15. A handover selection function which makes a selection regarding which of plural connections handled by the radio access network should have control thereof moved from a first control node to another of plural control nodes of a radio access network to alleviate congestion on an overloaded one of inter-control node links connecting the plural control nodes, the selection including making a determination of a cost for each of the connections carried by the overloaded link.