Improvements in and relating to L1 / L2 triggered mobility (LTM)

Abstract

Management of execution failure of Layer1 / Layer2 Triggered Mobility (LTM) in a User Equipment (UE) in a wireless communication network such as a 5G New Radio (NR) network. If an initial LTM execution attempt fails, the UE performs cell selection and if the selected cell is an LTM candidate cell and if the UE has been configured to attempt LTM after an LTM execution failure, then the UE attempts a further LTM execution. The LTM execution failure may be detected by one or more of: an expiry of a supervisor timer for the LTM cell switch, a Radio Link Failure (RLF) or a Beam Failure Detection (BFD). The LTM candidate cell may be configured via a Radio Resource Control (RRC) connection. The invention of the application may be used where a UE supports 5G dual connectivity. If the LTM execution failure is detected for a Secondary Cell Group (SCG) and if Master Cell Group (MCG) transmissions of radio bearers is not suspended, then the UE reports the failure to a Master Node of the MCG and does not attempt re-establishment.

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