Method and Arrangement in a Telecommunication System
The present invention relates to a method in a serving base station ( 130 ) for controlling handover of a relay node ( 140 ) to a target cell ( 150 A) controlled by a target base station ( 150 ). The method comprises the steps of obtaining information ( 91 ) indicating if the target base station and/or the target cell supports handling of relay nodes or not; avoiding handover of said relay node to said target cell in case the target base station and/or the target cell does not support handling of relay nodes ( 94 ). The invention furthermore relates to a base station for performing said method.
1 - 24 . (canceled)
25 . A method, in a serving base station, for controlling handover of a relay node to a target cell controlled by a target base station, the method comprising:
obtaining information indicating if the target base station and/or the target cell supports handling of relay nodes or not;
avoiding handover of the relay node to the target cell in response to the information indicating that the target base station and/or the target cell does not support handling of relay nodes.
26 . The method of claim 25 :
further comprising indicating to the target base station, in handover preparation signalling, that the handover preparation concerns a relay node;
wherein the obtaining information comprises receiving a response from the target base station.
27 . The method of claim 26 wherein the handover preparation signaling takes place over an S1 interface via a Mobility Management Entity.
28 . The method of claim 26 wherein the handover preparation signaling takes place over an X2 interface between the serving base station and the target base station.
29 . The method of claim 26 wherein the response comprises a rejection of handover in case the target base station and/or the target cell does not support handling of relay nodes.
30 . The method of claim 29 wherein the response comprises information relating to the cause for the rejection of handover.
31 . The method of claim 29 wherein the rejection of handover comprises a HANDOVER PREPARATION FAILURE message.
32 . The method of claim 29 further comprising storing information related to the rejection of handover.
33 . The method of claim 25 wherein the information indicating if the target base station and/or the target cell supports handling of relay nodes or not is obtained as neighbor relation information.
34 . The method of claim 33 wherein the neighbor relation information is received over an X2 interface between base stations.
35 . The method of claim 34 wherein the neighbor relation information is comprised in an eNB CONFIGURATION UPDATE message.
36 . The method of claim 33 wherein the neighbor relation information is received via a management system node.
37 . A base station capable of acting as serving base station, the base station comprising a processor, the processor configured to control handover of a relay node to a target cell controlled by a target base station by:
obtaining information indicating if the target base station and/or the target cell supports handling of relay nodes or not;
avoiding handover of the relay node to the target cell in response to the information indicating that the target base station and/or the target cell does not support handling of relay nodes.
38 . The base station of claim 37 further comprising:
a transmitter configured to indicate to the target base station, in handover preparation signalling, that the handover preparation concerns a relay node;
a receiver configured to obtain the information by receiving a response from the target base station.
39 . The base station of claim 38 wherein the transmitter is configured to send the handover preparation signaling over an S1 interface via a Mobility Management Entity.
40 . The base station of claim 38 wherein the transmitter is configured to send the handover preparation signaling over an X2 interface between a serving base station and a target base station.
41 . The base station of claim 38 wherein the response comprises a rejection of handover in case the target base station and/or the target cell does not support handling of relay nodes.
42 . The base station of claim 41 wherein the response comprises information relating to the cause for rejecting handover.
43 . The base station of claim 41 wherein the rejection of handover comprises a HANDOVER PREPARATION FAILURE message.
44 . The base station of claim 41 wherein the processor comprises circuitry for storing information related to the rejection of handover.
45 . The base station of claim 37 further comprising a receiver configured to receive neighbor relation information that comprises the information indicating if the target base station and/or the target cell supports handling of relay nodes or not.
46 . The base station of claim 45 wherein the receiver is configured to receive the neighbor relation information over an X2 interface.
47 . The base station of claim 46 wherein the receiver is configured to receive the neighbor relation information in an eNB CONFIGURATION UPDATE message.
48 . The base station of claim 45 wherein the receiver is configured to receive the neighbor relation information via a management system node.