Embodiments of this application provide a cell selection method and an apparatus, and relate to the communications field. A terminal may determine a first measurement frequency and a 5G anchor cell at the first measurement frequency based on prior historical information. The terminal may shorten evaluation duration corresponding to a 5G anchor cell that meets a preferred condition at a first measurement frequency, so as to improve a probability that the terminal camps on the 5G anchor cell.

A method and apparatus for secondary base station change in a mobile communication system are provided. Method for secondary node change includes receiving conditional reconfiguration information from the base station, performing evaluation based on the configuration generated by a second base station and transmitting a second response message with an identifier indicating which conditional reconfiguration is executed.

A method and apparatus for secondary base station change in a mobile communication system are provided. Method for secondary node change includes receiving conditional reconfiguration information from the base station, performing evaluation based on the configuration generated by a second base station and transmitting a second response message with an identifier indicating which conditional reconfiguration is executed.

A method for a user equipment (UE) connected to a serving Radio Access Network (RAN) through a serving cell is provided. The serving RAN may include a Non-Terrestrial Network (NTN). The method receives, from the serving cell, satellite information regarding a coverage area of the serving RAN. After receiving the satellite information, the method determines, based on the satellite information, that the UE will be disconnected from the serving RAN by moving out of the coverage area of the serving RAN after a specific period of time. The method maintains an Access Stratum (AS) layer configuration of the UE without performing any task associated with an Idle mode of the UE while the UE is staying out of the coverage area of the serving RAN.

A method and apparatus for selecting a NR cell in a mobile communication system are provided. Method for selecting a NR cell includes selecting, by a terminal, a first cell, performing, by the terminal a first operation group if the terminal fails to acquire MIB in the first cell and performing, by the terminal a second operation group if the terminal succeeds to acquire MIB and SIB1 in the first cell and the MIB includes cellBarred set to barred and the SIB1 includes a intraFreqReselection set to NotAllowed.

A method and apparatus for selecting a NR cell in a mobile communication system are provided. Method for selecting a NR cell includes selecting, by a terminal, a first cell, performing, by the terminal a first operation group if the terminal fails to acquire MIB in the first cell and performing, by the terminal a second operation group if the terminal succeeds to acquire MIB and SIB1 in the first cell and the MIB includes cellBarred set to barred and the SIB1 includes a intraFreqReselection set to NotAllowed.

A method for a conditional Primary Secondary Cell Group (SCG) Cell (PSCell) change (CPC) procedure performed by a user equipment (UE) is provided. The method includes: receiving, from a master node, a conditional reconfiguration for changing from a source PSCell to a target PSCell in an SCG portion of a radio resource control (RRC) reconfiguration message, the conditional reconfiguration including a configuration of the target PSCell and an execution condition; evaluating the execution condition; applying the configuration of the target PSCell and synchronizing to the target PSCell after determining that the execution condition is satisfied; and transmitting, to the master node, a response message after determining that the conditional reconfiguration is applied.

A method for a conditional Primary Secondary Cell Group (SCG) Cell (PSCell) change (CPC) procedure performed by a user equipment (UE) is provided. The method includes: receiving, from a master node, a conditional reconfiguration for changing from a source PSCell to a target PSCell in an SCG portion of a radio resource control (RRC) reconfiguration message, the conditional reconfiguration including a configuration of the target PSCell and an execution condition; evaluating the execution condition; applying the configuration of the target PSCell and synchronizing to the target PSCell after determining that the execution condition is satisfied; and transmitting, to the master node, a response message after determining that the conditional reconfiguration is applied.

A method for cell selection, a user equipment and a network side device are provided. The method includes: reading, by a UE, first system information of a first cell on a first frequency; in a case that the first system information of the first cell indicates that camping on the first cell is not allowed and an intra-frequency reselection is not allowed and in a case that a set condition is met, the UE not selecting, or not reselecting, or neither selecting nor reselecting a cell on the first frequency.

A method for cell selection, a user equipment and a network side device are provided. The method includes: reading, by a UE, first system information of a first cell on a first frequency; in a case that the first system information of the first cell indicates that camping on the first cell is not allowed and an intra-frequency reselection is not allowed and in a case that a set condition is met, the UE not selecting, or not reselecting, or neither selecting nor reselecting a cell on the first frequency.