Method and apparatus for transmitting user equipment group information in wireless communication system

1. A method for transmitting, by a source eNodeB (eNB) of a handover procedure, user equipment (UE) group information in a wireless communication system, the method comprising:

determining whether a ping-pong event is detected during the handover procedure,

wherein the ping-pong event specifies that a UE is handed over from a target eNB to the source eNB, after the UE is handed over from the source eNB to the target eNB;

if the ping-pong event is detected, transmitting a handover request message including the UE group information indicating a group, to which UEs concerned with the ping-pong event belong, to the target eNB,

wherein the UE group information is included in a UE history information IE (information element) of the handover request message,

wherein the UE group information indicates the group of the UEs to be applied different handover parameters during the handover procedure to avoid the ping-pong event between the source eNB and the target eNB.

2. The method of claim 1 , wherein the UE group information is forwarded, by the target eNB, to another target eNB of next handover procedure.

3. The method of claim 1 , wherein the UE group information includes whether the UE is served with cell range expansion (CRE) or not in a cell of the source eNB.

4. The method of claim 1 , wherein the UE group information includes whether the UE is moving with high speed, medium speed or low speed.

5. The method of claim 1 , wherein the UE group information includes whether the UE is served real time (RT) traffics or not.

6. The method of claim 1 , wherein the UE group information includes whether in-device coexistence (IDC) problems of the UE can be solved in a cell of the source eNB.

7. A source eNodeB (eNB) of a handover procedure in a wireless communication system, the source eNB comprising:

a radio frequency (RF) unit for transmitting or receiving a radio signal; and

a processor coupled to the RF unit, and configured to:

determine whether a ping-pong event is detected during the handover procedure,

wherein the ping-pong event specifies that a user equipment (UE) is handed over from a target eNB to the source eNB, after the UE is handed over from the source eNB to the target eNB;

if the ping-pong event is detected, transmit a handover request message including user equipment (UE) group information indicating a group, to which UEs concerned with the ping-pong event belong, to the target eNB,

wherein the UE group information is included in a UE history information IE (information element) of the handover request message,

wherein the UE group information indicates the group of the UEs to be applied different handover parameters during the handover procedure to avoid the ping-pong event between the source eNB and the target eNB.

8. The source eNB of claim 7 , wherein the UE group information is forwarded, by the target eNB, to another target eNB of next handover procedure.

9. The source eNB of claim 7 , wherein the UE group information includes whether the UE is served with cell range expansion (CRE) or not in a cell of the source eNB.

10. The source eNB of claim 7 , wherein the UE group information includes whether the UE is moving with high speed, medium speed or low speed.

11. The source eNB of claim 7 , wherein the UE group information includes whether the UE is served real time (RT) traffics or not.

12. The source eNB of claim 7 , wherein the UE group information includes whether in-device coexistence (IDC) problems of the UE can be solved in a cell of the source eNB.

13. A method for transmitting, by an eNodeB (eNB), user equipment (UE) group information in a wireless communication system, the method comprising:

determining whether a Radio Link Failure (RLF) is detected during a handover procedure,

wherein the RLF occurs when the handover procedure occurs at a wrong time or when the handover procedure is a handoff to a wrong cell;

if the RLF is detected, transmitting the UE group information indicating a group, to which UEs concerned with the RLF belong, to a target eNB of the handover procedure,

wherein the UEs concerned with the RLF are categorized by handling in the target eNB,

wherein the UE group information indicates the group of the UEs to be applied different handover parameters during the handover procedure to avoid the RLF with the target eNB.

14. The method of claim 13 , wherein the UE group information is included in an RLF indication message.

15. The method of claim 14 , wherein the eNB is an eNB that the UE reestablishes after the RLF has occurred.

16. The method of claim 13 , wherein the UE group information is included in a handover report message.

17. The method of claim 16 , wherein the eNB is an eNB that the RLF has occurred.