Failure Event Report Extension for Inter-RAT Radio Link Failure

Abstract

A method of inter-RAT failure event report is proposed. A UE detects a failure event in a first cell served by a first base station, and the first cell belongs to a first RAT. The failure event may include a radio link failure or a handover failure. The UE then performs an RRC establishment procedure with a second cell served by a second base station, and the second cell belongs to a second RAT. After the RRC establishment, the UE transmits a failure event report to the wireless network. The failure event can be a radio link failure, or be associated with a mobility command such as a handover command. By providing more reliable information in the failure event report than a network solution could provide, inter-RAT mobility performance can be improved.

What is claimed is: 
     
         1 . A method, comprising:
 detecting a failure event by a user equipment (UE) in a first cell served by a first base station in a wireless communication network, wherein the first cell belongs to a first radio access technology (RAT);   performing a radio resource control (RRC) establishment procedure with a selected second cell served by a second base station, wherein the second cell belongs to a second RAT as attempting to connect to the second RAT;   recording information related to attempting to the second RAT if the attempting to connect to the second RAT is unsuccessful; and   transmitting a failure event report to the first cell belongs to the first RAT, wherein the failure event report is related to the recorded information related to the unsuccessful attempting to connect to the second RAT, wherein the failure event report comprises an identity and a carrier frequency of the second RAT, and wherein the first RAT and second RAT belong to different radio access technologies.   
     
     
         2 . The method of  claim 1 , further comprising:
 receiving a mobility command by the UE to move a radio connection from the first RAT to the second RAT, wherein the mobility command is a handover command.   
     
     
         3 . A user equipment (UE), comprising:
 a failure event management circuit that detects a failure event in a first cell served by a first base station, wherein the first cell belongs to a first radio access technology (RAT);   a connection management circuit that performs a radio resource control (RRC) establishment procedure with a second cell served by a second base station, wherein the second cell belongs to a second RAT as attempting to connect to the second RAT, wherein the failure event management circuit records information related to attempting to the second RAT when the attempting to connect to the second RAT is unsuccessful; and   a transmitter that transmits a failure event report to the first cell belongs to the first RAT, wherein the failure event report comprises the recorded information related to the unsuccessful attempting to connect to the second RAT, wherein the failure event report comprises an identity and a carrier frequency of the second RAT, and wherein the first RAT and second RAT belong to different radio access technologies.   
     
     
         4 . The UE of  claim 3 , further comprising:
 a receiver that receives a mobility command to move a radio connection from the first RAT to the second RAT, wherein the mobility command is a handover command.