Patent Description:
In Release <NUM> of the Third-Generation Partnership Project (3GPP), E-UTRA-NR Dual Connectivity (EN-DC) is defined (see NPL <NUM>). In EN-DC, a User Equipment (UE) is connected to one evolved Node B (eNB) operating as a master node (MN) and an en-gNB operating as a secondary node (SN).

Further, as one function of EN-DC, a Secondary RAT Data Usage Report function is defined (see NPL <NUM>). The en-gNB counts (measures) the volume of user data transmitted between the en-gNB and the UE by using New Radio (NR) being a secondary Radio Access Technology (RAT), and reports the data volume to an MeNB (eNB being an MN) by using the X2AP: Secondary RAT Data Usage Report message.

However, a method of implementing the Secondary RAT Data Usage Report function has not yet been defined. More specifically, a method in which the en-gNB being an SN counts (measures) the data volume has not yet been defined.

The present invention provides a first base station and a second base station, and associated methods as defined in the appended independent claims. Optional features are defined in the appended dependent claims.

A first communication apparatus according to one disclosed example includes: an information obtaining unit configured to obtain data volume information indicating volume of data transmitted between a first base station and a terminal apparatus, the first base station operating for the terminal apparatus as a secondary node of dual connectivity using at least New Radio (NR); and a communication processing unit configured to transmit the data volume information to a second base station operating for the terminal apparatus as a master node of the dual connectivity. The volume of the data is data volume counted in a Packet Data Convergence Protocol (PDCP) layer or between the PDCP layer and a Radio Link Control (RLC) layer.

A second communication apparatus according to one disclosed example includes: a communication processing unit configured to receive, from a first base station operating for a terminal apparatus as a secondary node of dual connectivity using at least New Radio (NR), data volume information indicating volume of data transmitted between the first base station and the terminal apparatus. The volume of the data is data volume counted in a Packet Data Convergence Protocol (PDCP) layer or between the PDCP layer and a Radio Link Control (RLC) layer.

A terminal apparatus according to one disclosed example includes: a first communication processing unit configured to communicate with a first base station operating for the terminal apparatus as a secondary node of dual connectivity using at least NR; and a second communication processing unit configured to communicate with a second base station operating for the terminal apparatus as a master node of the dual connectivity. The first base station is configured to transmit data volume information indicating volume of data transmitted between the first base station and the terminal apparatus to the second base station. The volume of the data is data volume counted in a Packet Data Convergence Protocol (PDCP) layer or between the PDCP layer and a Radio Link Control (RLC) layer.

A first method according to one disclosed example includes: obtaining data volume information indicating volume of data transmitted between a first base station and a terminal apparatus, the first base station operating for the terminal apparatus as a secondary node of dual connectivity using at least New Radio (NR); and transmitting the data volume information to a second base station operating for the terminal apparatus as a master node of the dual connectivity. The volume of the data is data volume counted in a Packet Data Convergence Protocol (PDCP) layer or between the PDCP layer and a Radio Link Control (RLC) layer.

A second method according to one disclosed example includes: receiving, from a first base station operating for a terminal apparatus as a secondary node of dual connectivity using at least New Radio (NR), data volume information indicating volume of data transmitted between the first base station and the terminal apparatus. The volume of the data is data volume counted in a Packet Data Convergence Protocol (PDCP) layer or between the PDCP layer and a Radio Link Control (RLC) layer.

A third method according to one disclosed example includes: communicating with a first base station operating for a terminal apparatus as a secondary node of dual connectivity using at least NR; and communicating with a second base station operating for the terminal apparatus as a master node of the dual connectivity. The first base station is configured to transmit data volume information indicating volume of data transmitted between the first base station and the terminal apparatus to the second base station. The volume of the data is data volume counted in a Packet Data Convergence Protocol (PDCP) layer or between the PDCP layer and a Radio Link Control (RLC) layer.

In one disclosed example, a program for causing a processor to execute at least one of the first method, the second method, and the third method, or a non-transitory computer readable recording medium recording the program may be provided. Advantageous Effects of Invention.

According to one example, reporting of data volume from a secondary node (SN) to a master node (MN) in dual connectivity is enabled. Note that, according to one example, instead of or together with the above effects, other effects may be exerted.

Example embodiments of the present invention (hereinafter referred to as the "present example embodiment") will be described below in detail with reference to the accompanying drawings. Note that, in the Specification and drawings, elements to which similar descriptions are applicable are denoted by the same reference signs, and overlapping descriptions may hence be omitted.

Descriptions will be given in the following order.

First, an overview of the present example embodiment will be described.

In Release <NUM> of 3GPP, EN-DC is defined. In EN-DC, a UE is connected to one eNB operating as a master node (MN) and an en-gNB operating as a secondary node.

Further, as one function of EN-DC, a Secondary RAT Data Usage Report function is defined. The en-eNB counts (measures) the volume of user data transmitted between the en-eNB and the UE by using New Radio (NR) being a secondary RAT, and reports the data volume to an MeNB (eNB being an MN) by using the X2AP: Secondary RAT Data Usage Report message.

For example, regarding data transmitted between the SN and the UE through an MN Terminated bearer (MN Terminated SCG/Split bearer), processing of the Packet Data Convergence Protocol (PDCP) layer is performed in the MN, and processing of the Radio Link Control (RLC) layer or its lower layers is performed in the SN. In contrast, regarding data transmitted between the SN and the UE through an SN Terminated bearer (SN Terminated SCG/Split bearer), both of processing of the PDCP layer and processing of the RLC layer or its lower layers are performed in the SN. In this manner, although a processing route of data is complicated, how the SN (en-gNB) counts (measures) the data volume has not yet been defined.

Note that a method in which the SN counts (measures) the data volume is required not only in EN-DC but also in other DCs such as NG-RAN E-UTRA-NR Dual Connectivity (NGEN-DC) and NR-E-UTRA Dual Connectivity (NE-DC).

In the present example embodiment, for example, the volume of data transmitted between the first base station operating for a terminal apparatus as a secondary node (SN) of dual connectivity (DC) using at least New Radio (NR) and the terminal apparatus is counted in the PDCP layer or between the PDCP layer and the RLC layer.

The configuration described above enables, for example, reporting of the data volume from the secondary node (SN) to the master node (MN) in dual connectivity. Specifically, for example, the base station operating as an SN may be split into a central unit and a distributed unit(s), and processing of the PDCP layer is executed in the central unit (CU), irrespective of a type of the split (Higher Layer Split or Lower Layer Split). Thus, counting of the data volume in the PDCP layer or between the PDCP layer and the RLC layer may be performed by the CU that has a function of reporting the data volume to the MN. Consequently, the CU can report the counted data volume to the MN.

With reference to <FIG>, an example of a configuration of a system <NUM> according to the present example embodiment will be described. <FIG> is an explanatory diagram illustrating an example of a schematic configuration of the system <NUM> according to the present example embodiment. With reference to <FIG>, the system <NUM> includes a core network <NUM>, a first base station <NUM>, a second base station <NUM>, and a terminal apparatus <NUM>.

For example, the system <NUM> is a system that conforms to standards or specifications of 3GPP. More specifically, for example, the system <NUM> conforms to standards or specifications of the fifth generation (<NUM>) or New Radio (NR). The system <NUM> may conform to standards or specifications of Long Term Evolution (LTE) or System Architecture Evolution (SAE). LTE herein may be LTE-Advanced or enhanced LTE (eLTE), may be (normal) LTE, or may be LTE of other types.

The first base station <NUM> communicates with the core network <NUM> via an interface <NUM>. The second base station <NUM> communicates with the core network <NUM> via an interface <NUM>.

In one example, the core network <NUM> is an Evolved Packet Core (EPC) (that is, a core network of the Fourth-Generation (<NUM>)). In this case, for example, the interface <NUM> and the interface <NUM> are each an S1 interface.

In another example, the core network <NUM> may be a Fifth-Generation Core network (5GC). In this case, the interface <NUM> and the interface <NUM> may each be an NG interface.

The first base station <NUM> and the second base station <NUM> communicate with each other via an interface <NUM>.

The first base station <NUM> wirelessly communicates with the terminal apparatus <NUM>. The second base station <NUM> also wirelessly communicates with the terminal apparatus <NUM>. The terminal apparatus <NUM> supports dual connectivity, and for example, is simultaneously connected with the first base station <NUM> and the second base station <NUM>. In particular, in the present example embodiment, the first base station <NUM> operates as a secondary node (SN) of dual connectivity for the terminal apparatus <NUM>, and the second base station <NUM> operates as a master node (MN) of dual connectivity for the terminal apparatus <NUM>.

In the present example embodiment, regarding the dual connectivity, at least New Radio (NR) is used as a Radio Access Technology (RAT). In other words, at least one of the master node (second base station <NUM>) and the secondary node (first base station <NUM>) communicates with the terminal apparatus <NUM> by using NR. Note that the NR is a RAT of the Fifth-Generation (<NUM>) of 3GPP, and may be referred to as a New RAT (NR), a <NUM> NR (New Radio/RAT), or the like.

For example, the dual connectivity is dual connectivity using NR and LTE. In other words, one of the master node (second base station <NUM>) and the secondary node (first base station <NUM>) communicates with the terminal apparatus <NUM> by using NR, and the other communicates with the terminal apparatus <NUM> by using LTE. As described above, LTE herein may be LTE-Advanced or enhanced LTE (eLTE), may be (normal) LTE, or may be LTE of other types.

In one example, the dual connectivity is EN-DC, the first base station <NUM> is an en-gNB, and the second base station <NUM> is a Master eNB (MeNB). In other words, the second base station <NUM> (MeNB) being a master node (MN) communicates with the terminal apparatus <NUM> by using LTE as a RAT, and the first base station <NUM> (en-gNB) being a secondary node (SN) communicates with the terminal apparatus <NUM> by using NR as a RAT. In this case, the core network <NUM> is an EPC, and the interface <NUM> between the first base station <NUM> and the second base station <NUM> is an X2 interface.

<FIG> is an explanatory diagram for describing an example of layer processing of each radio bearer according to the present example embodiment. With reference to <FIG>, the first base station <NUM> (en-gNB) being a secondary node (SN), the second base station <NUM> (MeNB) being a master node (MN), and their respective radio bearers are illustrated. The radio bearers include an MN Terminated bearer that is terminated at an MN (i.e., that has the PDCP located in an MN) and an SN Terminated bearer that is terminated at an SN (i.e., that has the PDCP located in an SN). Further, the MN Terminated bearer includes a Master Cell Group (MCG) bearer, a Secondary Cell Group (SCG) bearer, and a Split bearer. In a similar manner, the SN Terminated bearer includes an MCG bearer, an SCG bearer, and a Split bearer. The MCG bearer is a radio bearer having an RLC bearer only in the MCG, and processing of the RLC layer, the MAC layer, and the physical layer regarding the MCG bearer is performed in the MN (second base station <NUM>). The SCG bearer is a radio bearer having an RLC bearer only in the SCG, and processing of the RLC layer, the MAC layer, and the physical layer regarding the SCG bearer is performed in the SN (first base station <NUM>). The Split bearer is a radio bearer having an RLC bearer both in the MCG and the SCG, and processing of the RLC layer, the MAC layer, and the physical layer regarding the Split bearer is performed in both of the MN (second base station <NUM>) and the SN (first base station <NUM>).

Note that, although an example in which the dual connectivity is EN-DC has been described, the present example embodiment is not limited to this example.

In one example, the dual connectivity may be NGEN-DC, the first base station <NUM> may be a gNB operating as an SN, and the second base station <NUM> may be an ng-eNB operating as an MN. In this case, the core network <NUM> may be a 5GC, and the interface <NUM> between the first base station <NUM> and the second base station <NUM> may be an Xn interface.

In another example, the dual connectivity may be NE-DC, the first base station <NUM> may be an ng-gNB operating as an SN, and the second base station <NUM> may be a gNB operating as an MN. In this case, the core network <NUM> may be a 5GC, and the interface <NUM> between the first base station <NUM> and the second base station <NUM> may be an Xn interface.

Alternatively, the dual connectivity may be dual connectivity using NR (without using LTE). In other words, both of the master node (second base station <NUM>) and the secondary node (first base station <NUM>) may communicate with the terminal apparatus <NUM> by using NR. The first base station <NUM> may be a gNB operating as an SN, and the second base station <NUM> may be a gNB operating as an MN. In this case, the core network <NUM> may be a 5GC, and the interface <NUM> between the first base station <NUM> and the second base station <NUM> may be an Xn interface.

Note that the first base station <NUM> may be a base station of a first operator, and the second base station <NUM> may be a base station of a second operator that is different from the first operator. In other words, the dual connectivity may be dual connectivity among operators.

For example, the first base station <NUM> includes a central unit (CU) and one or more distributed units (DUs).

<FIG> is an explanatory diagram for describing an example of split of the first base station <NUM> according to the present example embodiment. With reference to <FIG>, a central unit (CU) <NUM> and distributed units (DUs) <NUM> included in the first base station <NUM> are illustrated. The CU <NUM> and each of the DUs <NUM> communicate with each other via an interface <NUM>. In this example, two DUs <NUM> are illustrated. However, the first base station <NUM> may include three or more DUs <NUM>, or may include only one DU <NUM>.

For example, the first base station <NUM> is split by a Higher Layer Split.

<FIG> is an explanatory diagram for describing a first example of split of the first base station <NUM> according to the present example embodiment. With reference to <FIG>, the CU <NUM> and the DU <NUM> included in the first base station <NUM> are illustrated. The PDCP layer is located in the CU <NUM>, and the RLC layer, the MAC layer, and the physical (PHY) layer are located in the DU <NUM>. In other words, the CU <NUM> executes processing of the PDCP layer, and the DU <NUM> executes processing of the RLC layer, the MAC layer, and the PHY layer. In this case, the interface <NUM> is an F1 interface.

Although an example in which the PDCP layer is located in the CU <NUM> has been described with reference to <FIG>, the Service Data Adaptation Protocol (SDAP) layer may be located in the CU <NUM> particularly in a case of NGEN-DC or NE-DC.

In such a case of the Higher Layer Split, data transmitted between the SN (first base station <NUM>) and the terminal apparatus <NUM> through the MN Terminated bearer may be transmitted between the MN (second base station <NUM>) and the DU <NUM> of the SN via the CU <NUM> of the SN (first example). Alternatively, the data may be directly transmitted between the MN (second base station <NUM>) and the DU <NUM> of the SN without passing through the CU <NUM> of the SN (second example).

<FIG> is an explanatory diagram for describing an example of a data route regarding the MN Terminated bearer according to the present example embodiment. With reference to <FIG>, the CU <NUM> and the DU <NUM> included in the first base station <NUM>, and the second base station <NUM> are illustrated. In the first example, data transmitted between the SN (first base station <NUM>) and the terminal apparatus <NUM> through the MN Terminated bearer may be transmitted between the MN (second base station <NUM>) and the DU <NUM> of the SN via the CU <NUM>. In other words, the data may be transmitted in a route <NUM> via the interface <NUM> (for example, X2-U) and the interface <NUM> (for example, F1-U). In the second example, the data may be directly transmitted between the MN (second base station <NUM>) and the DU <NUM> of the SN without passing through the CU <NUM>. In other words, the data may be transmitted in a route <NUM>.

Note that, although an example of split of the first base station <NUM> has been described, the second base station <NUM> may also be split in a similar manner to the first base station <NUM>. Alternatively, to the second base station <NUM>, a split (for example, a Lower Layer Split) that is different from the split (Higher Layer Split) of the first base station <NUM> may be applied.

Alternatively, the first base station <NUM> may be split by a Lower Layer Split.

<FIG> is an explanatory diagram for describing a second example of split of the first base station <NUM> according to the present example embodiment. With reference to <FIG>, the CU <NUM> and the DU <NUM> included in the first base station <NUM> are illustrated. As illustrated in <FIG>, the PDCP layer, the RLC layer, the MAC layer, and the physical (PHY) layer (upper part) may be located in the CU <NUM>, and the PHY layer (lower part) may be located in the DU <NUM>.

In other words, the CU <NUM> may execute processing of the PDCP layer, the RLC layer, the MAC layer, and the PHY layer (upper part), and the DU <NUM> may execute processing of the PHY layer (lower part).

Note that, although an example of split of the first base station <NUM> has been described, the second base station <NUM> may also be split in a similar manner to the first base station <NUM>. Alternatively, to the second base station <NUM>, a split (for example, a Higher Layer Split) that is different from the split (Lower Layer Split) of the first base station <NUM> may be applied.

With reference to <FIG>, a configuration of each node will be described.

<FIG> is a block diagram illustrating an example of a schematic configuration of the CU <NUM> according to the present example embodiment. With reference to <FIG>, the CU <NUM> includes a first network communication unit <NUM>, a second network communication unit <NUM>, a storage unit <NUM>, and a processing unit <NUM>.

The first network communication unit <NUM> receives a signal from the DU <NUM>, and transmits a signal to the DU <NUM>.

The second network communication unit <NUM> receives a signal from the second base station <NUM>, and transmits a signal to the second base station <NUM>.

The second network communication unit <NUM> may receive a signal from the core network <NUM>, and may transmit a signal to the core network <NUM>.

The storage unit <NUM> temporarily or permanently stores programs (instructions) and parameters for operations of the CU <NUM> as well as various data. The program includes one or more instructions for operations of the CU <NUM>.

The processing unit <NUM> provides various functions of the CU <NUM>. The processing unit <NUM> includes a first communication processing unit <NUM>, a second communication processing unit <NUM>, a counting unit <NUM>, and an information obtaining unit <NUM>. The counting unit <NUM> may be referred to as a measurement unit <NUM>. Note that the processing unit <NUM> may further include constituent elements other than these constituent elements. In other words, the processing unit <NUM> may also perform operations other than the operations of these constituent elements.

For example, the processing unit <NUM> (first communication processing unit <NUM>) communicates with the DU <NUM> via the first network communication unit <NUM>. For example, the processing unit <NUM> (second communication processing unit <NUM>) communicates with the second base station <NUM> (or the core network <NUM>) via the second network communication unit <NUM>.

Each of the first network communication unit <NUM> and the second network communication unit <NUM> may be implemented with a network adapter and/or a network interface card and the like. The storage unit <NUM> may be implemented with a memory (for example, a nonvolatile memory and/or a volatile memory) and/or a hard disk or the like. The processing unit <NUM> may be implemented with one or more processors, such as a baseband (BB) processor and/or a different kind of processor. The first communication processing unit <NUM>, the second communication processing unit <NUM>, the counting unit <NUM>, and the information obtaining unit <NUM> may be implemented with the same processor, or may be implemented with separate processors. The memory (storage unit <NUM>) may be included in the one or more processors, or may be provided outside the one or more processors.

The CU <NUM> may include a memory configured to store a program (instructions) and one or more processors that can execute the program (instructions). The one or more processors may execute the program and thereby perform operations of the processing unit <NUM> (operations of the first communication processing unit <NUM>, the second communication processing unit <NUM>, the counting unit <NUM>, and/or the information obtaining unit <NUM>). The program may be a program for causing the processor to execute operation of the processing unit <NUM> (operations of the first communication processing unit <NUM>, the second communication processing unit <NUM>, the counting unit <NUM>, and/or the information obtaining unit <NUM>).

Note that the CU <NUM> may be virtual. In other words, the CU <NUM> may be implemented as a virtual machine. In this case, the CU <NUM> (the virtual machine) may operate as a physical machine (hardware) including a processor, a memory, and the like, and a virtual machine on a hypervisor.

<FIG> is a block diagram illustrating an example of a schematic configuration of the DU <NUM> according to the present example embodiment. With reference to <FIG>, the DU <NUM> includes a radio communication unit <NUM>, a network communication unit <NUM>, a storage unit <NUM>, and a processing unit <NUM>.

The radio communication unit <NUM> wirelessly transmits and/or receives a signal. For example, the radio communication unit <NUM> receives a signal from the terminal apparatus <NUM>, and transmits a signal to the terminal apparatus <NUM>.

The network communication unit <NUM> receives a signal from the CU <NUM>, and transmits a signal to the CU <NUM>. The network communication unit <NUM> may receive a signal from another node (for example, the second base station <NUM>), and may transmit a signal to such another node.

The storage unit <NUM> temporarily or permanently stores programs (instructions) and parameters for operations of the DU <NUM> as well as various data. The program includes one or more instructions for operations of the DU <NUM>.

The processing unit <NUM> provides various functions of the DU <NUM>. The processing unit <NUM> includes a first communication processing unit <NUM> and a second communication processing unit <NUM>. Note that the processing unit <NUM> may further include constituent elements other than these constituent elements. In other words, the processing unit <NUM> may also perform operations other than the operations of these constituent elements.

For example, the processing unit <NUM> (first communication processing unit <NUM>) communicates with the terminal apparatus <NUM> via the radio communication unit <NUM>. For example, the processing unit <NUM> (second communication processing unit <NUM>) communicates with the CU <NUM> (or the second base station <NUM>) via the network communication unit <NUM>.

The radio communication section <NUM> may be implemented with an antenna, a radio frequency (RF) circuit, and the like, and the antenna may be a directional antenna. The network communication unit <NUM> may be implemented with a network adapter and/or a network interface card and the like. The storage unit <NUM> may be implemented with a memory (for example, a nonvolatile memory and/or a volatile memory) and/or a hard disk or the like. The processing unit <NUM> may be implemented with one or more processors, such as a baseband (BB) processor and/or a different kind of processor. The first communication processing unit <NUM> and the second communication processing unit <NUM> may be implemented with the same processor, or may be implemented with separate processors. The memory (storage unit <NUM>) may be included in the one or more processors, or may be provided outside the one or more processors.

The DU <NUM> may include a memory configured to store a program (instructions) and one or more processors that can execute the program (instructions). The one or more processors may execute the program and thereby perform operations of the processing unit <NUM> (operations of the first communication processing unit <NUM> and/or the second communication processing unit <NUM>). The program may be a program for causing the processor(s) to perform operations of the processing unit <NUM> (operations of the first communication processing unit <NUM> and the second communication processing unit <NUM>).

Note that the DU <NUM> may be virtual. In other words, the DU <NUM> may be implemented as a virtual machine. In this case, the DU <NUM> (the virtual machine) may operate as a physical machine (hardware) including a processor, a memory, and the like, and a virtual machine on a hypervisor.

<FIG> is a block diagram illustrating an example of a schematic configuration of the second base station <NUM> according to the present example embodiment. With reference to <FIG>, the second base station <NUM> includes a radio communication unit <NUM>, a network communication unit <NUM>, a storage unit <NUM>, and a processing unit <NUM>.

The network communication unit <NUM> receives a signal from the first base station <NUM> or the core network <NUM>, and transmits a signal to the first base station <NUM> or the core network <NUM>.

The storage unit <NUM> temporarily or permanently stores programs (instructions) and parameters for operations of the second base station <NUM> as well as various data. The program includes one or more instructions for operations of the second base station <NUM>.

The processing unit <NUM> provides various functions of the second base station <NUM>. The processing unit <NUM> includes a first communication processing unit <NUM>, a second communication processing unit <NUM>, and a counting unit <NUM>. The counting unit <NUM> may be referred to as a measurement unit <NUM>. Note that the processing unit <NUM> may further include constituent elements other than these constituent elements. In other words, the processing unit <NUM> may also perform operations other than the operations of these constituent elements.

For example, the processing unit <NUM> (first communication processing unit <NUM>) communicates with the terminal apparatus <NUM> via the radio communication unit <NUM>. For example, the processing unit <NUM> (second communication processing unit <NUM>) communicates with the first base station <NUM> or the core network <NUM> via the network communication unit <NUM>.

The radio communication unit <NUM> may be implemented with an antenna, a radio frequency (RF) circuit, and the like, and the antenna may be a directional antenna. The network communication unit <NUM> may be implemented with a network adapter and/or a network interface card and the like. The storage unit <NUM> may be implemented with a memory (e.g., a nonvolatile memory and/or a volatile memory) and/or a hard disk, and the like. The processing unit <NUM> may be implemented with one or more processors, such as a baseband (BB) processor and/or a different kind of processor. The first communication processing unit <NUM>, the second communication processing unit <NUM>, and the counting unit <NUM> may be implemented with the same processor, or may be implemented with separate processors. The memory (storage unit <NUM>) may be included in the one or more processors, or may be provided outside the one or more processors.

The second base station <NUM> may include a memory configured to store a program (instructions) and one or more processors that can execute the program (instructions). The one or more processors may execute the program and thereby perform operations of the processing unit <NUM> (operations of the first communication processing unit <NUM>, the second communication processing unit <NUM>, and/or the counting unit <NUM>). The program may be a program for causing the processor to execute operation of the processing unit <NUM> (the first communication processing unit <NUM>, the second communication processing unit <NUM>, and/or the counting unit <NUM>).

The second base station <NUM> may include a central unit (CU) and a distributed unit(s) (DU). The CU may include the network communication unit <NUM> and the second communication processing unit <NUM> (and the counting unit <NUM>), and the DU may include the radio communication unit <NUM> and the first communication processing unit <NUM>.

Note that the second base station <NUM> (or the CU or the DU constituting a part of the second base station <NUM>) may be virtual. In other words, the second base station <NUM> (or the CU or the DU constituting a part of the second base station <NUM>) may be implemented as a virtual machine. In this case, the second base station <NUM> (or the CU or the DU constituting a part of the second base station <NUM>) (the virtual machine) may operate as a physical machine (hardware) including a processor, a memory, and the like, and a virtual machine on a hypervisor.

<FIG> is a block diagram illustrating an example of a schematic configuration of the terminal apparatus <NUM> according to the present example embodiment. With reference to <FIG>, the terminal apparatus <NUM> includes a first radio communication unit <NUM>, a second radio communication unit <NUM>, a storage unit <NUM>, and a processing unit <NUM>.

The first radio communication unit <NUM> wirelessly transmits and/or receives a signal. For example, the first radio communication unit <NUM> receives a signal from the first base station <NUM>, and transmits a signal to the first base station <NUM>.

The second radio communication unit <NUM> wirelessly transmits and/or receives a signal. For example, the second radio communication unit <NUM> receives a signal from the second base station <NUM>, and transmits a signal to the second base station <NUM>.

The storage unit <NUM> temporarily or permanently stores programs (instructions) and parameters for operations of the terminal apparatus <NUM> as well as various data. The program includes one or more instructions for operations of the terminal apparatus <NUM>.

The processing unit <NUM> provides various functions of the terminal apparatus <NUM>. The processing unit <NUM> includes a first communication processing unit <NUM> and a second communication processing unit <NUM>. Note that the processing unit <NUM> may further include constituent elements other than these constituent elements. In other words, the processing unit <NUM> may also perform operations other than the operations of these constituent elements.

For example, the processing unit <NUM> (first communication processing unit <NUM>) communicates with the first base station <NUM> via the first radio communication unit <NUM>. For example, the processing unit <NUM> (second communication processing unit <NUM>) communicates with the second base station <NUM> via the second radio communication unit <NUM>.

Each of the first radio communication unit <NUM> and the second radio communication unit <NUM> may be implemented with an antenna, a radio frequency (RF) circuit, and the like. The storage unit <NUM> may be implemented with a memory (e.g., a nonvolatile memory and/or a volatile memory) and/or a hard disk, and the like. The processing unit <NUM> may be implemented with one or more processors, such as a baseband (BB) processor and/or a different kind of processor. The first communication processing unit <NUM> and the second communication processing unit <NUM> may be implemented with the same processor, or may be implemented with separate processors. The memory (storage unit <NUM>) may be included in the one or more processors, or may be provided outside the one or more processors. As an example, the processing section <NUM> may be implemented in a system on chip (SoC).

The terminal apparatus <NUM> may include a memory configured to store a program (instructions) and one or more processors that can execute the program (instructions). The one or more processors may be a program for causing the processor to execute operation of the processing unit <NUM> (operations of the first communication processing unit <NUM> and/or the second communication processing unit <NUM>) by executing the program.

With reference to <FIG>, a first example embodiment of the present invention will be described.

The first base station <NUM> operates as a secondary node (SN) of dual connectivity using at least NR for the terminal apparatus <NUM>, and the second base station <NUM> operates as a master node (MN) of the dual connectivity for the terminal apparatus <NUM>. In this case, the first base station <NUM> (SN) obtains data volume information indicating the volume of data transmitted between the first base station <NUM> and the terminal apparatus <NUM>, and transmits the data volume information to the second base station <NUM> (MN).

More specifically, the CU <NUM> (information obtaining unit <NUM>) included in the first base station <NUM> (SN) obtains the data volume information, and the CU <NUM> (second communication processing unit <NUM>) transmits the data volume information to the second base station <NUM> (MN).

For example, the CU <NUM> (second communication processing unit <NUM>) transmits a message including the data volume information to the second base station <NUM>. Specifically, for example, the dual connectivity is EN-DC, the interface <NUM> between the first base station <NUM> and the second base station <NUM> is an X2 interface, and the message is an X2 message. For example, the message is a Secondary RAT Data Usage Report message. Further, for example, the data volume information is a Usage count UL and a Usage count DL. The Usage count UL and the Usage count DL may be referred to as a Data Usage UL and a Data Usage DL, respectively. The data volume information may be data usage volume.

<FIG> and <FIG> are each an explanatory diagram for describing an example of a SECONDARY RAT DATA USAGE REPORT message according to the first example embodiment. <FIG> illustrates details of the SECONDARY RAT DATA USAGE REPORT message, and the SECONDARY RAT DATA USAGE REPORT message includes a Secondary RAT Usage Report list. <FIG> illustrates details of the Secondary RAT Usage Report list, and the Secondary RAT Usage Report list includes a Usage count UL IE and a Usage count DL IE (i.e., counted data volume).

As illustrated in <FIG> as well, for example, the data volume information includes information of each bearer (information indicating the volume of data of each bearer). The bearer herein may be a radio bearer (RB), or may be a radio access bearer (RAB). Alternatively, the data volume information may include information of each QoS flow (information indicating the volume of data of each QoS flow).

The first base station <NUM> counts the volume of the data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM>. Note that the expression "to count" may be replaced with the expression "to measure".

In particular, the first base station <NUM> counts the volume of the data in the PDCP layer or between the PDCP layer and the RLC layer.

As has been described with reference to <FIG> and <FIG>, processing of the PDCP layer is performed by the CU <NUM> irrespective of the type of split of the first base station <NUM>. Thus, the CU <NUM> (counting unit <NUM>) of the first base station <NUM> counts the volume of the data.

For example, the first base station <NUM> (CU <NUM>: counting unit <NUM>) counts the data volume of packets of the PDCP. For example, such a packet may be a protocol data unit (PDU) of the PDCP. Alternatively, the packet may be another data unit (for example, a service data unit (SDU) of the PDCP).

The configuration described above enables, for example, reporting of the data volume from the secondary node (SN) to the master node (MN) in dual connectivity. Specifically, for example, the first base station <NUM> operating as an SN is split into the CU <NUM> and the DU(s) <NUM>, and processing of the PDCP layer is executed in the CU <NUM> irrespective of a type of the split (Higher Layer Split or Lower Layer Split). Thus, counting of the data volume in the PDCP layer or between the PDCP layer and the RLC layer may be performed by the CU <NUM> that handles reporting the data volume to the MN. Consequently, the CU <NUM> can report the counted data volume to the MN.

In the first example embodiment, the data (to be a target of counting of data volume) is first data transmitted between the first base station <NUM> and the terminal apparatus <NUM> through at least one radio bearer terminated at the secondary node (SN) (first base station <NUM>). In other words, the first base station <NUM> (CU <NUM>: counting unit <NUM>) counts the volume of the first data.

For example, the at least one radio bearer terminated at the SN (first base station <NUM>) includes an SN Terminated bearer, and the first data is data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> through a Split bearer and an SCG bearer being respectively in the SN Terminated bearer.

Note that, in the first example embodiment, the data (to be a target of counting of data volume) does not include second data transmitted between the first base station <NUM> and the terminal apparatus <NUM> through a radio bearer terminated at the master node (MN) (second base station <NUM>). In other words, the first base station <NUM> (CU <NUM>: counting unit <NUM>) does not count the volume of the second data.

In the first example embodiment, instead of the first base station <NUM>, the second base station <NUM> (counting unit <NUM>) counts the volume of the second data.

For example, the radio bearer terminated at the MN (second base station <NUM>) includes an MN Terminated bearer, and the second data is data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> through a Split bearer and an SCG bearer being respectively in the MN Terminated bearer.

As described above, the volume of the first data transmitted through the radio bearer (SN Terminated bearer) terminated at the SN is counted by the first base station <NUM> being the SN, and the volume of the second data transmitted through the radio bearer (MN Terminated bearer) terminated at the MN is counted by the second base station <NUM> being the MN.

The configuration described above enables, for example, further reduction of reporting (of the data volume) from the SN (first base station <NUM>) to the MN (second base station <NUM>). For example, the configuration may further facilitate counting of the data volume.

For example, counting of data volume is performed for each bearer. The bearer herein may be a radio bearer (RB), or may be a radio access bearer (RAB). Alternatively, counting of the data volume may be performed for each QoS flow.

For example, the data (the first data) (to be a target of counting of data volume) includes downlink data transmitted from the first base station <NUM> to the terminal apparatus <NUM> and uplink data transmitted from the terminal apparatus <NUM> to the first base station <NUM>.

For example, the first base station <NUM> (CU <NUM>: counting unit <NUM>) counts the volume of the downlink data, based on a status of delivery of the downlink data to the terminal apparatus <NUM>. For example, the status of the delivery is a delivery status confirmed in a layer (for example, the RLC layer) that is lower than the PDCP layer.

For example, the CU <NUM> executes processing of the PDCP layer, and the DU <NUM> executes processing of the RLC layer (and its lower layers) (Higher Layer Split). In this case, the status of the delivery is information transmitted from the DU <NUM> to the CU <NUM> (via an F1 interface). In one example, the status of the delivery is indicated in a DL DATA DELIVERY STATUS frame.

Alternatively, the CU <NUM> may execute processing of the PDCP layer, the RLC layer, the MAC layer, and the PHY layer (upper part), and the DU <NUM> may execute processing of the PHY layer (lower part) (Lower Layer Split). In this case, the status of the delivery may be information generated by the CU <NUM> itself.

The configuration described above enables, for example, counting of the data volume based on whether or not the terminal apparatus <NUM> has actually received downlink data, regardless of whether the data volume is to be counted in the PDCP layer or the data volume is to be counted between the PDCP layer and the RLC layer.

Note that the second data transmitted between the first base station <NUM> and the terminal apparatus <NUM> through a radio bearer terminated at the MN (second base station <NUM>) may also include downlink data transmitted from the first base station <NUM> to the terminal apparatus <NUM> and uplink data transmitted from the terminal apparatus <NUM> to the first base station <NUM>. In this case, the second base station <NUM> (counting unit <NUM>) may count the volume of the downlink data, based on a status of delivery of the downlink data to the terminal apparatus <NUM>. The status of the delivery may be a delivery status confirmed in a layer (for example, the RLC layer) that is lower than the PDCP layer. The status of the delivery may be information transmitted from the first base station <NUM> to the second base station <NUM>, and may be indicated in a DL DATA DELIVERY STATUS frame.

The second base station <NUM> (first communication processing unit <NUM>) receives the message including the data volume information from the first base station <NUM> (CU <NUM>).

For example, the second base station <NUM> (second communication processing unit <NUM>) further transmits, to the core network <NUM>, a message with the data volume information (other data volume information indicating the volume of the second data).

For example, the message transmitted to the core network <NUM> includes the data volume information (and such other data volume information), and includes information indicating the volume of data of each bearer (or QoS flow). Alternatively, the message transmitted to the core network <NUM> may further include other data volume information (for example, aggregated data volume information) that is generated based on the data volume information (and such other data volume information) (by the second base station <NUM>).

For example, the dual connectivity is EN-DC, the interface <NUM> between the second base station <NUM> and the core network <NUM> is an S1 interface, and the message is an S1 message. More specifically, for example, the message is a SECONDARY RAT REPORT message, and includes a Usage count UL IE and a Usage count DL IE (i.e., counted data volume). The Usage count UL and the Usage count DL may be referred to as a Data Usage UL and a Data Usage DL, respectively. The data volume information may be data usage volume.

<FIG> is a sequence diagram for describing an example of a general flow of processing according to the first example embodiment.

The first base station <NUM> (CU <NUM>) being an SN counts the volume of first data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> through the SN Terminated bearer in the PDCP layer (S601).

The second base station <NUM> being an MN counts the volume of second data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> through the MN Terminated bearer in the PDCP layer (S603).

The first base station <NUM> (CU <NUM>) transmits, to the second base station <NUM>, a SECONDARY RAT DATA USAGE REPORT message including data volume information (Usage count UL IE and Usage count DL IE) indicating the counted volume of the first data (S605).

Note that the second base station <NUM> may further transmit, to the core network <NUM>, a SECONDARY RAT REPORT message (SECONDARY RAT REPORT message including Usage count UL IE and Usage count DL IE) with the data volume information (other data volume information indicating the volume of the second data).

With reference to <FIG>, the first example embodiment of the present invention will be described.

In this respect, there is no difference in description between the first example embodiment and the second example embodiment. Thus, redundant description will be herein omitted.

In the second example embodiment, the data (to be a target of counting of data volume) includes first data transmitted between the first base station <NUM> and the terminal apparatus <NUM> through a radio bearer terminated at the secondary node (SN) (first base station <NUM>) and second data transmitted between the first base station <NUM> and the terminal apparatus <NUM> through a radio bearer terminated at the master node (MN) (second base station <NUM>). Thus, the data volume information includes first data volume information indicating the volume of the first data and second data volume information indicating the volume of the second data.

For example, the radio bearer terminated at the SN (first base station <NUM>) is an SN Terminated bearer, and the first data is data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> through a Split bearer and an SCG bearer being respectively in the SN Terminated bearer.

For example, the radio bearer terminated at the MN (second base station <NUM>) is an MN Terminated bearer, and the second data is data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> through a Split bearer and an SCG bearer being respectively in the MN Terminated bearer.

As described above, in the second example embodiment, the first base station <NUM> (CU <NUM>) also counts the volume of the second data transmitted through a radio bearer terminated at the MN (second base station <NUM>). Regarding the second data, processing of the PDCP layer is performed in the second base station <NUM> (MN), and processing of the RLC layer and its lower layers is performed in the first base station <NUM> (SN). Thus, the first base station <NUM> (CU <NUM>) counts at least the volume of the second data between the PDCP layer and the RLC layer. In one example, the first base station <NUM> (CU <NUM>) includes an entity for counting the data volume between the PDCP layer and the RLC layer, and the entity (counting unit <NUM>) counts at least the volume of the second data. Note that, for example, the first base station <NUM> (CU <NUM>) also counts the volume of the first data between the PDCP layer and the RLC layer. Alternatively, the first base station <NUM> (CU <NUM>) may count the volume of the first data in the PDCP layer.

In the second example embodiment, for example, the CU <NUM> executes processing of the PDCP layer, and the DU <NUM> executes processing of the RLC layer (and its lower layers) (Higher Layer Split). As has been described with reference to <FIG>, in a case of the Higher Layer Split, the second data is transmitted in a route (route <NUM>) passing through the CU <NUM> or in a direct route (route <NUM>) without passing through the CU <NUM>. In particular, in the second example embodiment, the second data is transmitted between the second base station <NUM> (MN) and the DU <NUM> via the CU <NUM>. In other words, the second route is transmitted in the route <NUM> illustrated in <FIG>. Then, the volume of the second data is counted by the CU <NUM>. The configuration described above enables, for example, counting of the data volume with the CU <NUM> even in a case of the Higher Layer Split.

As described above, both of the volume of the first data transmitted through the radio bearer (SN Terminated bearer) terminated at the SN and the volume of the second data transmitted through the radio bearer (MN Terminated bearer) terminated at the MN are counted by the first base station <NUM> being the SN.

The configuration described above enables, for example, obtaining of data volume information indicating the volume of data transmitted between the SN (first base station <NUM>) and the terminal apparatus <NUM> without the MN (second base station <NUM>) itself counting the data volume.

For example, the data (the first data and the second data) (to be a target of counting of data volume) includes downlink data transmitted from the first base station <NUM> to the terminal apparatus <NUM> and uplink data transmitted from the terminal apparatus <NUM> to the first base station <NUM>.

For example, the second base station <NUM> (second communication processing unit <NUM>) further transmits, to the core network <NUM>, a message with the data volume information.

For example, the message transmitted to the core network <NUM> includes the data volume information, and includes information indicating the volume of data of each bearer (or QoS flow). Alternatively, the message transmitted to the core network <NUM> may include other data volume information (for example, aggregated data volume information) that is generated based on the data volume information (by the second base station <NUM>).

For example, the dual connectivity is EN-DC, the interface <NUM> between the second base station <NUM> and the core network <NUM> is an S1 interface, and the message is an S1 message. More specifically, for example, the message is a SECONDARY RAT REPORT message, and includes a Usage count UL IE and a Usage count DL IE (i.e., counted data volume).

<FIG> is a sequence diagram for describing an example of a general flow of processing according to the second example embodiment.

The first base station <NUM> (CU <NUM>) being an SN counts the volume of data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> between the PDCP layer and the RLC layer (S621). The data includes first data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> through the SN Terminated bearer and second data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> through the MN Terminated bearer.

The first base station <NUM> (CU <NUM>) transmits, to the second base station <NUM>, a SECONDARY RAT DATA USAGE REPORT message including data volume information (Usage count UL IE and Usage count DL IE) indicating the counted volume of the data (S623).

Note that the second base station <NUM> may further transmit, to the core network <NUM>, a SECONDARY RAT REPORT message (SECONDARY RAT REPORT message including Usage count UL IE and Usage count DL IE) with the data volume information.

With reference to <FIG>, example alterations of the present example embodiment will be described.

In particular, in an example alteration of the present example embodiment, the central unit (CU) <NUM> includes a first central unit for a control plane and a second central unit for a user plane.

<FIG> is an explanatory diagram for describing an example of split of the first base station <NUM> according to an example alteration of the present example embodiment. With reference to <FIG>, the first base station <NUM> includes a central unit (CU) <NUM> and distributed units (DUs) <NUM>. Further, in the example alteration of the present example embodiment, the CU <NUM> includes a CU-CP <NUM> being the first central unit for the control plane and a CU-UP being the second central unit for the user plane. There may be a plurality of CU-UPs <NUM> for one CU-CP <NUM>. Each of the DUs <NUM> communicates with the CU-CP <NUM> via an interface <NUM>, and communicates with the CU-UP <NUM> via an interface <NUM>.

For example, the CU <NUM> executes processing of the PDCP layer, and each DU <NUM> executes processing of the RLC layer and the MAC layer. In other words, the first base station <NUM> is split by the Higher Layer Split.

<FIG> is an explanatory diagram for describing an example of split (Higher Layer Split) of the first base station <NUM> according to an example alteration of the present example embodiment. With reference to <FIG>, the CU <NUM> and the DU <NUM> included in the first base station <NUM> are illustrated. The PDCP layer is located in the CU <NUM>, and the RLC layer, the MAC layer, and the physical (PHY) layer are located in the DU <NUM>. In other words, the CU <NUM> executes processing of the PDCP layer, and the DU <NUM> executes processing of the RLC layer, the MAC layer, and the PHY layer. Further, the control plane of the PDCP layer is located in the CU-CP <NUM>, and the user plane of the PDCP layer is located in the CU-UP <NUM>. In this case, the interface <NUM> is an F1-C interface, and the interface <NUM> is an F1-U interface.

Alternatively, in the example alteration of the present example embodiment, the CU <NUM> may execute processing of the PDCP layer and processing of the RLC layer and the MAC layer. In other words, the first base station <NUM> may be split by the Lower Layer Split.

Referring back to <FIG>, for example, the counting unit <NUM> of the CU <NUM> is included in the CU-UP <NUM>, and the information obtaining unit <NUM> and the second communication processing unit <NUM> of the CU <NUM> are included in the CU-CP <NUM>.

The CU-UP <NUM> (counting unit <NUM>) counts the volume of data transmitted between the first base station <NUM> (SN of dual connectivity using at least NR) and the terminal apparatus <NUM>. Then, the CU-UP <NUM> (communication processing unit) transmits data volume information indicating the volume of the data to the CU-CP <NUM>.

The CU-CP <NUM> (information obtaining unit <NUM>) obtains the data volume information. Then, the CU-CP <NUM> (second communication processing unit <NUM>) transmits the data volume information to the second base station <NUM> (MN of the dual connectivity).

<FIG> is a sequence diagram for describing an example of a general flow of processing according to an example alteration of the first example embodiment.

The CU-UP <NUM> of the first base station <NUM> being an SN counts the volume of first data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> through the SN Terminated bearer in the PDCP layer (S641).

The second base station <NUM> being an MN counts the volume of second data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> through the MN Terminated bearer in the PDCP layer (S643).

The CU-UP <NUM> transmits data volume information indicating the counted volume of the first data to the CU-CP <NUM> of the first base station <NUM> (S645).

The CU-CP <NUM> transmits, to the second base station <NUM>, a SECONDARY RAT DATA USAGE REPORT message including the data volume information (Usage count UL IE and Usage count DL IE) (S647).

<FIG> is a sequence diagram for describing an example of a general flow of processing according to an example alteration of the second example embodiment.

The CU-UP <NUM> of the first base station <NUM> being an SN counts, between the PDCP layer and the RLC layer, the volume of data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> (S661). The data includes first data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> through the SN Terminated bearer and second data transmitted between the first base station <NUM> (SN) and the terminal apparatus <NUM> through the MN Terminated bearer.

The CU-UP <NUM> transmits data volume information indicating the counted volume of the data to the CU-CP <NUM> of the first base station <NUM> (S663).

The CU-CP <NUM> transmits, to the second base station <NUM>, a SECONDARY RAT DATA USAGE REPORT message including the data volume information (Usage count UL IE and Usage count DL IE) (S665).

With reference to <FIG>, a third example embodiment of the present invention will be described. The first example embodiment and the second example embodiment described above are concrete example embodiments, whereas the third example embodiment is a more generalized example embodiment.

<FIG> is a block diagram illustrating an example of a schematic configuration of a first communication apparatus <NUM> according to the third example embodiment. With reference to <FIG>, the first communication apparatus <NUM> includes an information obtaining unit <NUM> and a communication processing unit <NUM>. Concrete operations of the information obtaining unit <NUM> and the communication processing unit <NUM> will be described later.

The information obtaining unit <NUM> and the communication processing unit <NUM> may be implemented with one or more processors such as a baseband (BB) processor and/or a different kind of processor and a memory (for example, a nonvolatile memory and/or a volatile memory) and/or a hard disk. The memory may be included in the one or more processors, or may be provided outside the one or more processors.

The first communication apparatus <NUM> may include a memory configured to store a program (instructions) and one or more processors that can execute the program (instructions). The one or more processors may execute the program and thereby perform operations of the information obtaining unit <NUM> and the communication processing unit <NUM>. The program may be a program for causing the processor(s) to perform the operations of the information obtaining unit <NUM> and the communication processing unit <NUM>.

Note that the first communication apparatus <NUM> may be virtual. In other words, the first communication apparatus <NUM> may be implemented as a virtual machine. In this case, the first communication apparatus <NUM> (the virtual machine) may operate as a physical machine (hardware) including a processor, a memory, and the like, and a virtual machine on a hypervisor.

<FIG> is a block diagram illustrating an example of a schematic configuration of a second communication apparatus <NUM> according to the third example embodiment. With reference to <FIG>, the second communication apparatus <NUM> includes a communication processing unit <NUM>. Concrete operations of the communication processing unit <NUM> will be described later.

The communication processing unit <NUM> may be implemented with one or more processors such as a baseband (BB) processor and/or a different kind of processor and a memory (for example, a nonvolatile memory and/or a volatile memory) and/or a hard disk. The memory may be included in the one or more processors, or may be provided outside the one or more processors.

The second communication apparatus <NUM> may include a memory configured to store a program (instructions) and one or more processors that can execute the program (instructions). The one or more processors may execute the program and thereby perform operations of the communication processing unit <NUM>. The program may be a program for causing the processor(s) to perform the operations of the communication processing unit <NUM>.

Note that the second communication apparatus <NUM> may be virtual. In other words, the second communication apparatus <NUM> may be implemented as a virtual machine. In this case, the second communication apparatus <NUM> (the virtual machine) may operate as a physical machine (hardware) including a processor, a memory, and the like, and a virtual machine on a hypervisor.

<FIG> is a block diagram illustrating an example of a schematic configuration of a terminal apparatus <NUM> according to the third example embodiment. With reference to <FIG>, the terminal apparatus <NUM> includes a first communication processing unit <NUM> and a second communication processing unit <NUM>. Concrete operations of the first communication processing unit <NUM> and the second communication processing unit <NUM> will be described later.

The first communication processing unit <NUM> and the second communication processing unit <NUM> may be implemented with one or more processors such as a baseband (BB) processor and/or a different kind of processor and a memory (for example, a nonvolatile memory and/or a volatile memory) and/or a hard disk. The memory may be included in the one or more processors, or may be provided outside the one or more processors.

The terminal apparatus <NUM> may include a memory configured to store a program (instructions) and one or more processors that can execute the program (instructions). The one or more processors may execute the program and thereby perform operations of the first communication processing unit <NUM> and the second communication processing unit <NUM>. The program may be a program for causing the processor(s) to perform operations of the first communication processing unit <NUM> and the second communication processing unit <NUM>.

An example of technical features according to the third example embodiment will be described.

The first communication apparatus <NUM> (information obtaining unit <NUM>) obtains data volume information indicating the volume of data transmitted between the first base station operating as a secondary node of dual connectivity using at least NR for the terminal apparatus <NUM> and the terminal apparatus <NUM>. The first communication apparatus <NUM> (communication processing unit <NUM>) transmits the data volume information to the second base station operating as a master node of the dual connectivity for the terminal apparatus <NUM>.

In particular, the volume of the data is data volume counted in the PDCP layer or between the PDCP layer and the RLC layer.

For example, the first communication apparatus <NUM> is the first base station, or a central unit (CU) included in the first base station. In one example, the first communication apparatus <NUM> is the first base station <NUM> or the CU <NUM> of the first example embodiment or the second example embodiment, and the information obtaining unit <NUM> and the communication processing unit <NUM> are the information obtaining unit <NUM> and the second communication processing unit <NUM>, respectively.

The second communication apparatus <NUM> (communication processing unit <NUM>) receives the data volume information from the first base station.

For example, the second communication apparatus <NUM> is the second base station, or a CU included in the second base station. In one example, the second communication apparatus <NUM> is the second base station <NUM> or the CU of the second base station <NUM> of the first example embodiment or the second example embodiment, and the communication processing unit <NUM> is the second communication processing unit <NUM>.

The terminal apparatus <NUM> (first communication processing unit <NUM>) communicates with the first base station. The terminal apparatus <NUM> (second communication processing unit <NUM>) communicates with the second base station.

In one example, the terminal apparatus <NUM> is the terminal apparatus <NUM> of the first example embodiment or the second example embodiment, and the first communication processing unit <NUM> and the second communication processing unit <NUM> are the first communication processing unit <NUM> and the second communication processing unit <NUM>, respectively.

Note that the third example embodiment is not limited to the example described above.

Descriptions have been given above of the example embodiments of the present invention. However, the present invention is not limited to these example embodiments. It should be understood by those of ordinary skill in the art that these example embodiments are merely examples and that various alterations are possible without departing from the scope of the present invention.

For example, the steps in the processing described in the Specification may not necessarily be carried out in time series in the order described in the corresponding sequence diagram. For example, the steps in the processing may be carried out in an order different from that described in the corresponding sequence diagram or may be carried out in parallel. Some of the steps in the processing may be deleted, or more steps may be added to the processing.

An apparatus (one of a plurality of partial apparatuses constituting each node, or a module for the node or the partial apparatus) including a constituent element (for example, the communication processing unit, the counting unit, and/or the information obtaining unit) of each node (the first base station, the CU, the DU, the second base station, or the terminal apparatus) described in the Specification may be provided. Moreover, methods including processing of the constituent elements may be provided, and programs for causing a processor to execute processing of the constituent elements may be provided. Moreover, non-transitory computer readable recording media (non-transitory computer readable media) having recorded thereon the programs may be provided. It is apparent that such partial apparatuses, modules, methods, programs, and non-transitory computer readable recording media are also included in the present invention.

Claim 1:
A first base station (<NUM>) being a secondary node, SN, in Dual Connectivity comprising,
a count unit (<NUM>) configured to count volume of data transmitted through SN-terminated MCG bearer between User Equipment, UE, (<NUM>) and the first base station hosting Packet Data Convergence Protocol, PDCP, layer, and
a process unit (<NUM>) to send a SECONDARY RAT DATA USAGE REPORT message to a second base station (<NUM>) being a master node, MN, of the dual connectivity,
wherein the SECONDARY RAT DATA USAGE REPORT message includes a first information element indicating the volume of data through the SN-terminated MCG bearer for which the PDCP layer is located in the SN.