A base station device is able to perform radio communication with a mobile terminal that exists in a first cell, and includes a memory and a transmitter. The memory stores therein position information on a second cell that can be a move destination for the mobile terminal. The transmitter transmits the position information on the second cell to the mobile terminal so as to cause the mobile terminal to detect that the mobile terminal has approached the second cell using the position information.

A base station device is able to perform radio communication with a mobile terminal that exists in a first cell, and includes a memory and a transmitter. The memory stores therein position information on a second cell that can be a move destination for the mobile terminal. The transmitter transmits the position information on the second cell to the mobile terminal so as to cause the mobile terminal to detect that the mobile terminal has approached the second cell using the position information.

In switching a radio base station (SeNB) from a radio base station (SeNB#1) to a radio base station (SeNB#2) in an “Inter-node UP aggregation”, the occurrence of transmission delay of downlink data to a mobile station (UE) is avoided. A mobile communication method according to the present invention includes: stopping, by the radio base station (SeNB#1), scheduling of downlink data to the mobile station (UE), and sending an “SeNB change command” to the mobile station (UE), when receiving an “SeNB change request ack” from the radio base station (SeNB#2); notifying, by the mobile station (UE), a radio base station (MeNB) of at least one of already received downlink data and unreceived downlink data; and resending, by the radio base station (MeNB), the mobile station the downlink data that is not received by the mobile station (UE) in response to the notification.

In switching a radio base station (SeNB) from a radio base station (SeNB#1) to a radio base station (SeNB#2) in an “Inter-node UP aggregation”, the occurrence of transmission delay of downlink data to a mobile station (UE) is avoided. A mobile communication method according to the present invention includes: stopping, by the radio base station (SeNB#1), scheduling of downlink data to the mobile station (UE), and sending an “SeNB change command” to the mobile station (UE), when receiving an “SeNB change request ack” from the radio base station (SeNB#2); notifying, by the mobile station (UE), a radio base station (MeNB) of at least one of already received downlink data and unreceived downlink data; and resending, by the radio base station (MeNB), the mobile station the downlink data that is not received by the mobile station (UE) in response to the notification.

The present disclosure relates to a method and an apparatus for controlling carrier aggregation. In the method, a terminal performs carrier aggregation from a first base station so that a Pcell, which is one carrier from among carriers controlled by the first base station, is used for setting another carrier to be an Scell. The terminal performs carrier aggregation from a second base station so that one carrier having the function of the Pcell from among carriers controlled by the second base station, is used for setting another carrier to be an Scell. The terminal transceiver a downlink channel and an uplink channels with the first base station and the second base station, according to settings of the Pcell and the Scell of each of the first base station and the second base station.

The present disclosure relates to a method and an apparatus for controlling carrier aggregation. In the method, a terminal performs carrier aggregation from a first base station so that a Pcell, which is one carrier from among carriers controlled by the first base station, is used for setting another carrier to be an Scell. The terminal performs carrier aggregation from a second base station so that one carrier having the function of the Pcell from among carriers controlled by the second base station, is used for setting another carrier to be an Scell. The terminal transceiver a downlink channel and an uplink channels with the first base station and the second base station, according to settings of the Pcell and the Scell of each of the first base station and the second base station.

UE 100 performs, in a mobile communication system in which a small cell is arranged within a coverage of a macro cell, a cell reselection on the basis of neighboring cell information broadcast from the macro cell. The UE 100 acquire, in a connected state in which the UE 100 is connected to the macro cell, from a server 400 that manages small cell information on the small cell, the small cell information via the macro cell. The neighboring cell information broadcast from the macro cell is information on a neighboring cell other than the small cell. The UE 100 performs, in an idle state, the cell reselection on the small cell on the basis of the small cell information acquired from the server 400.

UE 100 performs, in a mobile communication system in which a small cell is arranged within a coverage of a macro cell, a cell reselection on the basis of neighboring cell information broadcast from the macro cell. The UE 100 acquire, in a connected state in which the UE 100 is connected to the macro cell, from a server 400 that manages small cell information on the small cell, the small cell information via the macro cell. The neighboring cell information broadcast from the macro cell is information on a neighboring cell other than the small cell. The UE 100 performs, in an idle state, the cell reselection on the small cell on the basis of the small cell information acquired from the server 400.

One disclosure of the present specification provides a method by which a user equipment (UE) communicates. The method comprises the steps of: camping on a first cell on a first frequency; receiving a first threshold and a second threshold from a base station serving the first cell; determining whether a low mobility condition is satisfied on the basis of the first threshold; determining whether a not-in cell edge condition is satisfied on the basis of the second threshold; and determining whether to relax a measurement for a second frequency, on the basis of i) whether the first frequency belongs to FR1 or FR2, ii) whether the low mobility condition is satisfied, and iii) whether the not-in cell edge condition is satisfied, wherein on the basis of the first frequency belonging to the FR1.

Disclosed are a signaling optimization method and device, to resolve a problem of heavy signaling overheads and long data transmission delay when a user equipment (UE) accesses a network side. The method includes: receiving, by the UE, configuration information sent by a first network side device, where the configuration information includes a list, and the list is a cell list or a base station list; and entering, by the UE, an intermediate state according to the configuration information, where the intermediate state means that: when the UE stores context information of the UE, if the UE moves and a cell movement range falls within a coverage area of a cell or a base station included in the list, the UE performs cell reselection according to the list. Embodiments of the present disclosure are applicable to optimization of signaling transmission between the UE and a network side.