BACKGROUND

Field

The present disclosure relates to a communication apparatus that can connect to a plurality of networks.

Description of the Related Art

A communication apparatus (user equipment (UE)) connected to a fourth generation (4G) public wireless communication line transitions between a plurality of states. More specifically, the communication apparatus transitions between two states, i.e., RRC_CONNECTED, which is a state where a communication band is secured and unicast data communication is being performed, and RRC_IDLE, which is a state where the communication band is not secured and the unicast data communication is not performed. In the RRC_IDLE state, the communication apparatus can only receive broadcast data.

In a communication apparatus connected to a fifth generation (5G) New Radio (NR) public wireless network, RRC_INACTIVE is added to the above two states. In the RRC_INACTIVE state, a communication band is secured and unicast data communication is not performed. In other words, the communication apparatus can only receive broadcast data. Using the transition between a plurality of Radio Resource Control (RRC) states, it is possible to save power and make efficient use of wireless communication resources.

US2013/0163497 discusses a mobile station that identifies whether a plurality of carrier bands in a carrier aggregation is continuous or intermittent, and can switch a timer for intermittent reception that is installed for a primary cell and a secondary cell to be common or independent. Intermittent reception control corresponding to the transmission cycle of a control signal from a base station is executed in the carrier aggregation, whereby it is possible to save the high power consumption of the mobile station.

SUMMARY

In fifth generation (5G) New Radio (NR), a communication apparatus can use dual connectivity (DC), in which the communication apparatus connects to a plurality of base stations (BSs) via a public wireless communication line and simultaneously provides communication services. A plurality of carriers is bundled between the plurality of base stations, whereby it is possible to perform broadband data communication.

However, the 3rd Generation Partnership Project (3GPP) standard does not define details of operation of the communication apparatus that is using two base stations based on DC in a case where the communication apparatus transitions to RRC_INACTIVE.

More specifically, the 3GPP standard defines that, during RRC_INACTIVE, the communication apparatus needs to monitor a paging channel (PCH), which is a control channel via which a control signal transmitted from a base station in use to all communication apparatuses in a cell is received. However, the 3GPP standard does not define whether the communication apparatus that is executing DC needs to monitor a PCH for a base station for a master cell group or a PCH for a base station for a secondary cell group during RRC_INACTIVE.

During RRC_INACTIVE, if the communication apparatus continues monitoring the PCHs for both the base station for the master cell group and the base station for the secondary cell group, the standby power increases.

On the other hand, during RRC_INACTIVE, if the communication apparatus monitors, for example, only the PCH for the base station for the master cell group, the communication apparatus cannot detect a change in quality of wireless line of the base station for the secondary cell group. Thus, the communication apparatus cannot determine whether the communication apparatus can return to RRC_CONNECTED based on DC using the two base stations until the communication apparatus returns to RRC_CONNECTED. This reduces responsiveness of the communication apparatus when resuming a service on standby for execution.

According to an aspect of the present disclosure, a communication apparatus includes a transition unit configured to, in a case where a wireless communication path to each of a first base station and a second base station is established, transition from an RRC_CONNECTED state to an RRC_INACTIVE state compliant with a 3rd Generation Partnership Project standard, and a control unit configured to, in a case where the transition unit transitions to the RRC_INACTIVE state, perform control to selectively execute operating in a first mode for waiting for a notification signal from each of the first and second base stations or operating in a second mode for waiting for a notification signal from either the first base station or the second base station, based on a state of the communication apparatus.

Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

