JP7315402B2 - Control device, control method and program - Google Patents

Description

The present invention relates to a control device and control method for a base station system to which network slicing is applied, and a program for the control device.

In the 5th generation (5G) mobile communication system, service types are broadly divided into three types: large capacity (eMBB: enhanced Mobile BroadBand), ultra-low delay (URLLC: Ultra-Reliable and Low Latency Communications), and multi-connection (mMTC: massive Machine Type Communications), each of which has different service requirements. In order to economically and flexibly provide services with different requirements, network slicing is being studied.

In addition, in 5G, the first version of which was formulated as 3GPP Release 15, a base station is configured with a logical node called a DU (Distributed Unit) and a logical node called a CU (Central Unit), and the functions of the base station are divided between the DU and the CU. In the DU, lower layer functions of the base station functions (RF (Radio Frequency layer), PHY (Physical layer), MAC (Media Access Control layer), RLC (Radio Link Control layer), PDCP (Packet Data Convergence Protocol layer)) are arranged in order from the lower layer, and other upper layer functions are arranged in the CU.

When the above-described network slicing is applied to a base station system in which functions are divided into DUs and CUs in this way, multiple schedulers each corresponding to one or more slices are arranged in different DUs. Each scheduler schedules radio resources for radio terminals within one or more corresponding slices. In a configuration in which a plurality of DUs share one radio unit (RU: Radio Unit) having functions such as RF and PHY, a plurality of schedulers perform scheduling using common radio resources within the same base station cell. For this reason, it is necessary to implement radio resource isolation so that competition for radio resources to be used does not occur between schedulers (between slices). Non-Patent Document 1 proposes a technique for allocating radio resources for scheduling to each slice based on a predetermined allocation ratio so as to ensure isolation between slices when network slicing is applied.

A. Ksentini and N. Nikaein "Toward Enforcing Network Slicing on RAN: Flexibility and Resources Abstraction," IEEE Communications Magazine, Jun. 2017, vol. 55, issue 6, pp. 102-108.

In the base station system as described above, it is necessary to allocate radio resources for scheduling to each scheduler so that radio resources can be efficiently used for scheduling radio terminals while maintaining the quality of service provided by each slice. However, the amount of radio resources required by each of the multiple schedulers varies depending on the communication data amount and radio communication quality of the radio terminals to be scheduled. For this reason, if radio resources are fixedly allocated to each scheduler, for example, there is a possibility that there will be a shortage or excess of radio resources in any one of the schedulers.

Also, if any scheduler cannot secure radio resources necessary for scheduling, a situation may arise in which the service itself cannot be provided to the radio terminal. For example, for radio terminals accessing slices providing mission-critical services, the scheduler needs to be able to appropriately allocate radio resources.

The present invention has been made in view of the above problems. An object of the present invention is to provide a technique for allocating radio resources in an amount suitable for scheduling radio resources within a predetermined period to a plurality of schedulers and enabling each scheduler to secure radio resources more appropriately.

A control device according to an aspect of the present invention is a control device that controls radio resources used by a scheduler that performs scheduling for allocating radio resources to radio terminals,Included in each individual DU (Distributed Unit)For each of the multiple schedulers,The same radio unit formed by one RU (radio unit)Identifying means for identifying the amount of radio resources required for each scheduler in a predetermined period based on the data amount and communication quality of radio communication by radio terminals in the cellwherein each of the plurality of schedulers corresponds to one or more slices and is configured to schedule radio resources for radio terminals using the corresponding slice within the same cell formed by the one RU.and an allocating means for allocating the amount of radio resources specified by the specifying means and a margin of the radio resources that can be used for the scheduling to each of the plurality of schedulers.

Advantageous Effects of Invention According to the present invention, it is possible to allocate an amount of radio resources suitable for scheduling radio resources within a predetermined period to a plurality of schedulers, and to enable each scheduler to secure radio resources more appropriately.

FIG. 3 is a diagram showing a functional configuration example of CU, DU, and RU in a base station system; The figure which shows the structural example of a base station system. FIG. 2 is a block diagram showing a hardware configuration example of a RAN controller; FIG. 2 is a block diagram showing a functional configuration example of a RAN controller; 4 is a flowchart showing the procedure of processing executed by a RAN controller; FIG. 4 is a diagram showing an example of arrangement of CUs, DUs and RUs in a base station system; FIG. 3 shows an example of UE information and margin information used by a RAN controller; FIG. 3 is a diagram showing an example of allocation of radio resources and margins to each DU (each scheduler); FIG. 4 is a diagram showing another example of arrangement of CUs, DUs and RUs in a base station system;

Exemplary embodiments of the invention will now be described with reference to the drawings. Note that, in each drawing below, constituent elements that are not necessary for the description of the embodiment are omitted from the drawing.

[First embodiment]
<Functional division of base station>
A base station (base station system) generally has a plurality of functions (RF, .

FIG. 1 is a diagram showing an example of a configuration in which multiple functions of different layers of a base station are divided into CUs, DUs, and RUs. As shown in FIG. 1, in this embodiment, in addition to CU and DU, RUs having functions such as RF and PHY are provided. The base station (base station system) in FIG.

The DU 20 has at least a scheduling function of allocating radio resources to radio terminals, among the functions of the base station. The CU 10 has, among the functions of the base station, higher layer functions than the functions of the connected DU 20 . Further, the RU 30 has at least an RF function corresponding to a radio transmission/reception function among the base station functions.

In the configuration example of FIG. 1, the DU 20 has not only the High MAC function corresponding to the scheduling function, but also the RLC and Low MAC functions. Further, the RU 30 has not only an RF function corresponding to a radio wave transmission/reception function, but also a PHY function. Note that only some functions of the PHY may be implemented in the RU 30 and the remaining functions of the PHY may be implemented in the DU 20.

Hereinafter, the configuration and operation of the base station system according to this embodiment and the control of the base station system will be specifically described using the functional configuration shown in FIG. 1 as an example.

<Configuration of base station system>
FIG. 2 is a diagram showing a basic configuration example of a base station system in which slices 1 to 3 corresponding to mMTC, URLLC, and eMBB are generated as service types. The CU 10 and DU 20 are controlled and managed by a RAN (radio access network) controller 40, and each slice is generated by the RAN controller 40. FIG.

The base station system consists of one or more CUs 10 (10a, 10b, 10c), one or more DUs 20 (20a, 20b, 20c), and one RU 30. CU10a and DU20a correspond to slice 1, CU10b and DU20b correspond to slice 2, and CU10c and DU20c correspond to slice 3. In this way, the multiple CUs 10 correspond to different slices, respectively, and the same applies to the multiple DUs 20 corresponding to the multiple CUs 10 . Note that each of the plurality of CUs 10 may correspond to one or more slices. Also, each of the plurality of DUs 20 may correspond to one or more slices.

The DU 20 has at least a radio resource scheduling function (for example, a High MAC function) among base station functions. The DUs 20 are each located at the antenna site or located between (the local station of) the antenna site and the data center.

Each CU 10 is arranged between one different DU out of DU 20 and the core network, and among the functions of the base station, the CU 10 has higher layer functions than those of the connected one DU (for example, SDAP/RRC and PDCP functions). In the example of FIG. 2, the CUs 10a, 10b, 10c are connected to one different DU 20a, 20b, 20c, respectively.

A single RU 30 has at least a radio wave transmission/reception function (for example, an RF function) among the base station functions. The RU 30 is placed at an antenna site and connected to multiple DUs 20 . Thereby, a plurality of slices 1 to 3 provided via a plurality of DUs 20 are provided within the same cell formed by the RU 30 concerned.

Thus, the base station system of the present embodiment is composed of CU10 and DU20 corresponding to slices 1 to 3, respectively, and a single RU connected to a plurality of DU20 and arranged at an antenna site. That is, the base station system has a configuration in which a plurality of DUs and CUs are connected to a single RU (that is, a plurality of DUs and CUs share an RU) without providing an RU for each slice. This allows a single RU to accommodate multiple services (slices).

In this embodiment, the core network or RAN is provided with a RAN controller 40, which is a control device that controls the functions of the RAN. The RAN controller 40 is communicably connected to the base station system on the RAN. The RAN controller 40 sets (generates) slices 1 to 3 corresponding to service requirements for one or more CUs 10 (10a, 10b, 10c) and one or more DUs 20 (20a, 20b, 20c) on the RAN. In this embodiment, the RAN controller 40 functions as an example of a control device that controls radio resources used by a scheduler that performs scheduling for allocating radio resources to radio terminals.

In the configuration example of FIG. 2, a 5G network configuration is assumed as an example, and a 5GC CPF (5GC Control Plane Function) 60 is a control processing function group of the 5G core network. A 5GC UPF (5G Core User Plane Function) 50 (50a, 50b, 50c) is a data processing function group of the 5G core network, and is provided for each slice. The 5GC UPF 50a corresponds to slice 1, the 5GC UPF 50b to slice 2, and the 5GC UPF 50c to slice 3.

In the configuration example of FIG. 2, the arrangement of the corresponding CU10 and DU20 differs depending on the slice (service). Depending on the placement of the CU 10 and DU 20, the performance of inter-base station cooperation (inter-cell cooperation), the amount of delay given to applications, the network utilization efficiency, etc., differ. Therefore, in the configuration example of FIG. 2, the CU 10 and DU 20 are arranged appropriately for each slice (service).

For slice 1 (mMTC slice), CU 10a is located at the data center where the core network is located, and DU 20a is located at the antenna site. This is to enable efficient utilization of data center computing resources due to statistical multiplexing effects.

For slice 2 (URLLC slice), CU 10b is located at the local station and DU 20b is located at the antenna site. This makes it possible to introduce MEC (Multi-Access Edge Computing) and achieve low delay. In this embodiment, the CU 10b is connected to an Edge App (Edge Application Server) 70, which is an edge server having an application for providing low-delay services located at an edge site. Note that the edge site where the Edge App 70 is arranged may be the local accommodation station where the CU 10b is arranged.

For slice 3 (eMBB slice), both CU 10c and DU 20c are located in the regional accommodation station. This allows the DU 20c to be connected to a plurality of RUs 30 arranged at different antenna sites. In the configuration example of FIG. 2, the DU 20c is connected to a plurality of RUs 30 forming different cells, and performs processing for inter-cell cooperation between the connected RUs (for example, CoMP (Coordinated Multi-Point Transmission/reception)). Thus, by enabling inter-cell cooperation, it is possible to improve radio communication quality.

As shown in FIG. 2, DUs 20a, 20b and 20c include schedulers 21a, 21b and 21c, respectively, that perform scheduling for allocating radio resources to radio terminals. In the configuration example of FIG. 2, schedulers 21a and 21b corresponding to slices 1 and 2 are arranged at antenna sites, and scheduler 21c corresponding to slice 3 is accommodated in a local station. In this way, the schedulers 21a and 21b and the scheduler 21c have different placement locations.

DUs 20a, 20b, and 20c containing schedulers 21a, 21b, and 21c, respectively, are connected to a common RU 30, as described above. The schedulers 21a, 21b, and 21c use common radio resources available in the same cell formed by the common RU 30 to schedule radio terminals using corresponding slices. Radio resources used for scheduling by the schedulers 21a, 21b, and 21c are allocated in advance by the RAN controller 40. FIG.

<Device configuration>
The RAN controller 40 has a hardware configuration as shown in FIG. 3 as an example. Specifically, the RAN controller 40 has a CPU 101 , a ROM 102 , a RAM 103 , an external storage device 104 such as an HDD, and a communication device 105 .

In the RAN controller 40, the CPU 101 executes a program that is stored in, for example, one of the ROM 102, the RAM 103, and the external storage device 104 and that implements each function of the RAN controller 40. FIG. Note that the CPU 101 may be replaced by one or more processors such as ASICs (Application Specific Integrated Circuits), FPGAs (Field Programmable Gate Arrays), DSPs (Digital Signal Processors), and the like.

The communication device 105 is a communication interface for communicating with external devices such as the CU 10 and the DU 20 to be controlled under the control of the CPU 101 . The RAN controller 40 may have multiple communication devices 105 with different connection destinations.

Note that the RAN controller 40 may include dedicated hardware for executing each function to be described later, or a part may be executed by hardware and the other part may be executed by a computer that operates a program. Also, all functions may be performed by computers and programs.

CU10, DU20 and RU30 may also have a hardware configuration as shown in FIG. However, as the communication device 105, the RU 30 also has a wireless communication interface for wireless communication with wireless terminals in addition to the communication interface for communication with each DU 20. FIG.

FIG. 4 is a block diagram showing a functional configuration example of the RAN controller 40. As shown in FIG. The RAN controller 40 of this embodiment has an information acquisition unit 41 , a resource control unit 42 , an allocation notification unit 43 and an information storage unit 44 . In the present embodiment, these functional units are realized on the CPU 101 by executing the control program by the CPU 101, but dedicated hardware for realizing each functional unit may be provided. Note that FIG. 4 shows only functional units related to allocation of radio resources to each scheduler 21 (each DU 20) among the functions of the RAN controller 40 (allocation of radio resources used for scheduling for each slice for each of a plurality of slices), and the functional units related to other functions are omitted. Also, the rule setting unit 45 shown in FIG. 4 is provided in the RAN controller 40 of the third embodiment, which will be described later.

The information acquisition unit 41 acquires information necessary for allocation (allocation) of radio resources to each scheduler 21 by the resource control unit 42 from at least one of the CU 10 , the DU 20 and the RU 30 . For example, the information acquisition unit 41 acquires the communication data amount and communication quality for one or more wireless terminals accessing the slice corresponding to each DU 20 . The information acquisition unit 41 stores the acquired information in the information storage unit 44 .

The resource control unit 42 allocates radio resources for scheduling to each scheduler 21 (each DU 20) based on the information obtained by the information obtaining unit 41, thereby controlling the radio resources used by each scheduler 21. The resource control unit 42 allocates radio resources and also allocates margins of radio resources that each scheduler 21 can use for scheduling.

The allocation notification unit 43 transmits a notification indicating allocation of radio resources and margins to each scheduler 21 according to the result of allocation of radio resources and margins to each scheduler 21 (each DU 20 ) by the resource control unit 42 . This completes the allocation of radio resources and margins to multiple schedulers 21 (multiple DUs 20).

The information storage unit 44 corresponds to a database provided in a storage device (eg, the RAM 103 or the external storage device 104), and stores information acquired by the information acquisition unit 41 and information used for processing by the resource control unit 42.

<Allocation processing of radio resources and margins>
In this embodiment, the RAN controller 40 allocates (distributes) radio resources to each scheduler 21 at predetermined time intervals. In addition to allocating radio resources, the RAN controller 40 also allocates a margin of radio resources that can be used for scheduling to each scheduler 21 when there is a shortage of radio resources.

Here, in the architecture of the base station system like this embodiment, schedulers can be arranged at different locations (sites). In the configuration example of FIG. 2, the scheduler 21c is arranged at a location different from that of the schedulers 21a and 21b. When multiple schedulers corresponding to different slices are located at different locations, it is generally difficult to update radio resource allocation for each scheduler 21 for each TTI (Transmission Time Interval), which is the minimum scheduling time unit. Therefore, the RAN controller 40 allocates radio resources (updates the allocation) to each scheduler 21 at time intervals longer than TTIs (for example, 100 TTIs).

FIG. 5 is a flowchart showing the procedure of allocation processing executed by the RAN controller 40 according to this embodiment. This assignment process is performed at least when setting slices for radio terminals (UEs) in a cell formed by the RU 30, or at timings every predetermined period T. The predetermined period T corresponds to the time interval described above for allocating radio resources to each scheduler 21 . In this embodiment, the RAN controller 40 executes the allocation process of FIG. 5 for each of the uplink and downlink.

In the following, an example of allocation processing will be described assuming the arrangement example shown in FIG. 6 as the arrangement of the CU10, DU20 and RU30. In the arrangement example of FIG. 6, RUs are arranged at antenna sites, DU#1 corresponding to slices 1 and 2 are arranged at local stations, and CU#1 corresponding to slices 1 and 2 are arranged at the data center. Also, DU#2 and CU#2 corresponding to slice 3 are arranged in the regional station. SLA#1, SLA#2, and SLA#3 are defined as service level agreements (SLAs) for slices 1 to 3, respectively.

First, in S<b>51 , the information acquisition unit 41 acquires the data amount (communication data amount) and communication quality of wireless communication by UEs in the cell formed by the RU 30 . The amount of communication data corresponds to, for example, the amount of data scheduled to be transmitted in the uplink or downlink during a predetermined period T from the current time. Also, the communication quality corresponds to the current (instantaneous) radio communication quality in radio communication performed by each UE, and is represented by, for example, a signal-to-noise ratio (S/N).

The information acquisition unit 41 acquires the amount of uplink data transmitted from each UE in the cell from notifications from each UE. Each UE notifies the scheduler 21 corresponding to the slice to be used of the amount of uplink data. Therefore, the information acquisition unit 41 can acquire, via the scheduler 21, the notification of the uplink data amount of each UE. In addition, the base station side (scheduler 21) grasps the downlink data amount. Therefore, the information acquisition unit 41 can acquire the downlink data amount of each UE based on the notification from the scheduler 21 .

In addition, the information acquisition unit 41 acquires the communication quality measurement result by the RU 30 as the uplink communication quality for each UE in the cell, and acquires the communication quality measurement result by each UE as the downlink communication quality for each UE in the cell. Measurement results of uplink communication quality can be obtained from the RU 30 . Measurement results of downlink communication quality can be obtained via the scheduler 21 by reporting from each UE to the scheduler 21 corresponding to the slice to be used.

The communication data amount and communication quality of each UE acquired by the information acquisition unit 41 are stored in the information storage unit 44 as UE information. FIG. 7A shows an example of UE information for each DU (scheduler), including communication data amount and communication quality of each UE. As described above, DU#1 is used for slice 1 (SLA#1) and slice 2 (SLA#2), and DU#2 is used for slice 3 (SLA#3). As shown in FIG. 7A, in the UE information, each UE is associated with the SLA of the slice to be used, and the communication data amount and communication quality (S/N) obtained by the information obtaining unit 41.

Next, in S52, the resource control unit 42 specifies the amount of radio resources required for each scheduler 21 (each DU) in a predetermined period T based on the communication data amount and communication quality of each UE in the cell acquired in S51. As a result, an appropriate amount of radio resources can be allocated for each scheduler 21 according to the amount of radio resources assumed to be required in a predetermined period T so as not to cause a situation in which radio resources are insufficient or excessive. The predetermined period T is determined as a period during which the data amount of radio communication by UEs in the cell formed by the RU 30 and the fluctuation amount of radio quality are equal to or less than a predetermined amount. As a result, the amount of radio resources assumed to be required for each scheduler 21 (each DU) in the predetermined period T can be specified with higher accuracy. In addition, by making the predetermined period T as long as possible within the range in which the amount of such fluctuation is equal to or less than the predetermined amount, it is possible to avoid frequently updating the allocation while maintaining the accuracy of radio resource allocation to each scheduler 21.

Specifically, the resource control unit 42 obtains the amount of radio resources required in a predetermined period T for each UE based on the communication data amount and communication quality of each UE in the cell. For example, the larger the amount of communication data, the larger the amount of required radio resources for each UE, and the smaller the amount of communication data, the smaller the amount of required radio resources for each UE. Also, the lower the communication quality (S/N), the larger the amount of radio resources required for each UE, and the higher the communication quality (S/N), the smaller the amount of required radio resources for each UE.

Furthermore, for each scheduler 21, the resource control unit 42 obtains the total amount of radio resources required for one or more UEs using the corresponding slice as the amount of radio resources required for the scheduler in a predetermined period T. In the example of FIG. 7(A), the amount of required radio resources for DU#1 in a predetermined period T is obtained as 1300 PRB from the total amount of required radio resources for each UE in units of physical resource blocks (PRBs). Similarly, the required amount of radio resources in the predetermined period T for DU#2 is obtained as 1100 PRB. When T=100 TTIs, the required amount of radio resources per TTI is 13 PRBs for DU#1 and 11 PRBs for DU#2.

Next, in S53, the resource control unit 42 determines margins of radio resources that can be used for scheduling when radio resource shortages occur, which are margins to be allocated to each of the plurality of schedulers 21 (plurality of DUs). By allocating this margin, each scheduler 21 can more appropriately secure necessary radio resources. In S53, the remaining amount of radio resources obtained by subtracting the required amount of radio resources for each scheduler 21 identified in S52 from the total amount of allocatable radio resources in the predetermined period T is allocated as a margin to the multiple schedulers by a predetermined method. A more specific example of the margin determination method will be described in the second and third embodiments.

Finally, in S54, the resource control unit 42 allocates the amount of radio resources specified in S52 to each of the plurality of schedulers 21 together with the margin of radio resources available for scheduling determined in S53. After that, the allocation notification unit 43 transmits a notification indicating allocation of radio resources and margins to each scheduler 21 according to the result of radio resource and margin allocation in S54. With the above, the allocation processing according to the procedure of FIG. 5 is completed.

FIG. 8A is a diagram showing an example of allocation of radio resources and margins to each DU (each scheduler 21). Note that FIG. 8A shows an example of allocation of radio resources and margins in one TTI when the total amount of allocatable radio resources in one TTI is 100 PRB. In this example, 13 PRBs are allocated as radio resources and 10 PRBs as a margin to DU#1. Also, 11 PRBs are allocated as radio resources and 66 PRBs as a margin to DU#2. In this example, the allocatable radio resources are divided for each TTI in the frequency direction and allocated to each DU, but the radio resources may be divided in the time direction. Division in the frequency direction is advantageous in terms of delay, while division in the time direction is advantageous in that the complexity of the scheduler is low.

The radio resources allocated to each of the plurality of schedulers 21 by the resource control unit 42 are used by each scheduler for scheduling UEs using the corresponding slice. Scheduling by each of the plurality of schedulers 21 is performed using radio resources within a range obtained by adding an allocated margin to the allocated radio resources.

As described above, in the base station system of the present embodiment, multiple schedulers 21 each corresponding to one or more slices schedule radio resources for UEs using the corresponding slices in the same cell formed by one RU 30. The RAN controller 40 identifies the amount of radio resources required for each scheduler in a predetermined period T based on the data amount and communication quality of radio communication by UEs in the cell for each of the plurality of schedulers 21 . Further, the RAN controller 40 allocates a specified amount of radio resources and a radio resource margin available for scheduling to each of the plurality of schedulers 21 .

According to the present embodiment, the RAN controller 40 identifies, for each scheduler (DU), the amount of radio resources required for each scheduler in a predetermined time period T, and allocates the identified amount of radio resources. As a result, it becomes possible to allocate an amount of radio resources suitable for scheduling radio resources within the predetermined period T to a plurality of schedulers 21 . As a result, it is possible to avoid situations in which radio resources are insufficient or excessive within the predetermined period T in any scheduler. In addition, the RAN controller 40 allocates radio resources and margins of radio resources that can be used for scheduling to the plurality of schedulers 21 . This makes it possible for each scheduler to secure radio resources more appropriately, and avoids a situation in which the service itself cannot be provided to the UE due to the inability to secure radio resources.

[Second embodiment]
In the second embodiment, a specific example of the process of distributing the remaining radio resources in the predetermined period T as a margin to each scheduler (each DU) as described in the first embodiment will be described. In the following, explanations of parts common to the first embodiment will be omitted.

In this embodiment, the resource control unit 42 distributes the remaining radio resources to the plurality of schedulers 21 as margins based on the slices used by the UEs in the cell formed by the RU 30 and the margin information predetermined for each slice. Here, the remaining radio resources correspond to the amount of radio resources obtained by subtracting the amount of necessary radio resources for each scheduler 21 identified in S52 (FIG. 5) from the total amount of allocatable radio resources in the predetermined period T. That is, the remaining radio resources correspond to surplus radio resources after allocating the required amount of radio resources specified in S52.

More specifically, the resource control unit 42 obtains the necessary margins for each of the plurality of schedulers 21, and distributes the remaining radio resources according to the obtained necessary margins. The required margin per scheduler (DU) can be determined by summing the required margins for one or more UEs using the corresponding slice in the cell.

The required margin for each UE is obtained as follows. For example, the margin information may be determined in advance and stored in the information storage unit 44 as information indicating the margin itself required when the UE uses each slice. In this case, the resource control unit 42 refers to the margin information stored in the information storage unit 44 and acquires the required margin corresponding to the slice used by each UE in the cell as the required margin of the UE.

In addition, the margin information is a coefficient value used to calculate the required margin for each UE for the UE to use the corresponding slice, and may be information indicating the coefficient value to be multiplied by the amount of required radio resources for each UE in a predetermined period T. In this case, the resource control unit 42 refers to the margin information stored in the information storage unit 44, acquires the coefficient value corresponding to the slice used by each UE in the cell, and the required radio resource amount of the UE obtained in S52 is multiplied by the coefficient value. As a result, the required margin for the UE is obtained from the required amount of radio resources for each UE.

FIG. 7B shows an example of such a coefficient value (multiplied value) associated with a slice (SLA) as an example of margin information. The UE information illustrated in FIG. 7(A) includes the required margin of each UE obtained from the amount of required radio resources using the coefficient values illustrated in FIG. 7(B). For example, the required radio resource (700 PRB) of UE#5 using slice 3 (SLA#3) is multiplied by a coefficient of 0.5 corresponding to SLA#3 to obtain the required margin (350 PRB). For a UE whose communication data amount and required radio resource are 0, the required margin obtained using the coefficient values described above is 0. However, like UE#6 in the example of FIG. 7(A), a required margin corresponding to communication quality (S/N) can be given to a UE whose required radio resource is 0 so that the required margin does not become 0.

The required margin of the UE may be determined by the following method instead of or in combination with the above method. For example, the required margin of the UE may be obtained based on the priority determined for the slices used by the UE. For example, a high priority is set for a slice that provides a high priority service such as a mission critical service, and a low priority is set for a slice that provides a low priority service such as a best effort service. According to such priority, when the UE uses a slice with a high priority, the required margin of the UE is increased, and when the UE uses a slice with a low priority, the required margin of the UE may be reduced.

Also, the required margin of the UE may be obtained based on the allowable delay defined for the slices used by the UE. For example, if a UE uses a slice that provides a service with a large allowable delay, such as a download service, the required margin for the UE may be reduced according to such an allowable delay. On the other hand, when a UE uses a slice that provides a service with a small allowable delay, such as an online competitive game, the necessary margin for the UE may be increased.

In this way, by changing the margin required for the UE according to the service provided by the slice, it is possible to reduce the impact of deterioration in service quality when radio resources become insufficient.

Also, the required margin of the UE may be obtained based on the priority determined for the operator that provides the scheduler 21 that schedules the UE. FIG. 9 shows a configuration example of a base station system in which an RU is shared by multiple operators (operators A and B), and multiple DUs provided by different operators are connected to the RU. When such a configuration is adopted, priority may be determined in advance for DUs (schedulers) for each operator. In this case, according to the priority determined for each operator, the necessary margin may be increased for the UEs to be scheduled by the DU (scheduler) provided by the operator with high priority. In addition, the required margin may be reduced for UEs scheduled by a DU (scheduler) provided by a low-priority operator.

After obtaining the required margin for each scheduler (DU) as described above, the resource control unit 42 allocates the remaining radio resources based on the ratio of the required margins of the plurality of schedulers 21 . According to the example of FIG. 7A, for DU#1, the remaining radio resources are allocated based on the ratio of the required margin for DU#1 (26+20+100+17=163 [PRB]) and the required margin for DU#2 (350+500+200=1050 [PRB]). For example, as in the example of FIG. 8A, if the total amount of allocatable radio resources in one TTI is 100 PRB, and 13 PRB radio resources are allocated to DU#1 and 11 PRB radio resources are allocated to DU#2, the remaining radio resources are 76 PRB. In this case, if the remaining radio resources (76 PRBs) are distributed based on the above ratio, a margin of 10 PRBs for DU#1 and a margin of 66 PRBs for DU#2 are determined as shown in FIG. 8(A).

According to this embodiment, as the radio resource margin for the multiple schedulers 21, it is possible to determine an appropriate amount of margin so as not to cause a situation in which the service itself cannot be provided to the UE due to the inability to secure the radio resource.

[Third embodiment]
In the third embodiment, an example will be described in which overlapping margins are allocated between schedulers when allocating (allocating) the remaining radio resources in a predetermined period T to each scheduler as margins. Below, the description of the parts common to the first and second embodiments will be omitted.

In this embodiment, in S53 (FIG. 5), the resource control unit 42 determines part of the remaining radio resources as an overlapping margin to be redundantly allocated between the schedulers so that the total amount of margins allocated to the multiple schedulers 21 exceeds the amount of the remaining radio resources. In this case, depending on how each scheduler 21 (each DU) uses the margin, there is a possibility that the use of the same radio resource by a plurality of schedulers will compete, causing signal interference in the cell or failure to allocate radio resources. However, it is possible to reduce the possibility of a situation in which one scheduler runs out of radio resources while another scheduler has surplus radio resources (that is, margin division loss).

<Determination of overlap margin>
In this embodiment, the information acquisition unit 41 accumulates, in the information storage unit 44, performance information indicating the past performance of redundant scheduling between schedulers for radio resources corresponding to overlapping margins. The resource control unit 42 determines the overlap margin according to the performance information accumulated in the information storage unit 44. FIG. FIG. 8(B) shows an example in which part of the remaining radio resources is determined as an overlap margin between the scheduler for DU#1 and the scheduler for DU#2. Both the scheduler for DU#1 and the scheduler for DU#2 can use the radio resources of this overlapping margin for scheduling when the allocated radio resources are insufficient.

In order to determine such overlapping margins, the information acquisition unit 41 acquires scheduling results from each of the plurality of schedulers 21, and accumulates performance information in the information storage unit 44 based on the scheduling results of the plurality of schedulers.

The resource control unit 42 controls the amount of overlap margin to be allocated thereafter according to the amount of radio resources that have been redundantly scheduled between schedulers in the past, indicated by the performance information accumulated by the information storage unit 44.

Further, the resource control unit 42 may determine an overlapping margin between schedulers for each combination of schedulers among the plurality of schedulers 21 . For example, if the multiple schedulers include first, second and third schedulers (DU#1, DU#2 and DU#3), the resource control unit 42 may determine the overlap margin such that the amount of overlap margin for the combination of the first and second schedulers (DU#1 and DU#2) is greater than the amount of overlap margin for the combination of the first and third schedulers (DU#1 and DU#3).

In determining such an overlap margin, the amount of overlap margin for each scheduler combination is controlled according to the priority determined for the slices corresponding to each scheduler used by the UEs in the cell formed by RU 30.

<Setting rules for using overlapping margins>
In this embodiment, the rule setting unit 45 of the RAN controller 40 sets rules for using the overlapping margins assigned by the resource control unit 42 to the RUs 30 for the overlapping margins determined as described above. The rule setting unit 45 sets rules to prevent schedulers from simultaneously using radio resources allocated as overlapping margins. This makes it less likely that multiple schedulers will compete for use on the same radio resource, resulting in signal interference in the cell or failure to allocate radio resources.

FIG. 8B shows an example of rules for using such overlapping margins. In this example, the schedulers for DU #1 and DU #2 first use the radio resources with margins other than the overlapping margins assigned to them, and when the radio resources with the margins are used up, the overlapping margins are used.

Also, the rule setting unit 45 may set the usage rule according to the priority determined for the slice corresponding to each scheduler used by the UE in the cell. Specifically, the rule setting unit 45 may set the usage rule such that the allocation of the radio resource corresponding to the overlap margin by the scheduler corresponding to the slice with high priority is prioritized over the allocation of the radio resource corresponding to the overlap margin by the scheduler corresponding to the slice with low priority.

In this case, the rule setting unit 45 notifies the RU 30 of the priority determined for each slice corresponding to each of the plurality of schedulers 21 . RU 30 determines which of the two or more schedulers should give priority to radio resource allocation according to the notified priority, when the radio resources corresponding to the overlapping margins are redundantly scheduled between two or more schedulers.

As described above, by allocating overlapping margins between schedulers to a plurality of schedulers, it is possible to reduce the possibility of a situation in which one scheduler lacks radio resources while another scheduler has surplus radio resources.

[Other embodiments]
Various modifications can be made to the first to third embodiments described above. For example, it is possible to configure the base station system so that each DU 20 performs the processes of S51 and S52 among the processes of S51 to S54 in FIG. Specifically, each DU 20 may identify the amount of radio resources required for the scheduler 21 of the DU based on the communication data amount and communication quality of each UE, and notify the RAN controller 40 of the identification result. In this case, the RAN controller 40 can receive notifications from each DU 20 and perform the processes of S53 and S54 in the same manner as in the above-described embodiment.

In addition to the processing of S51 and S52, it is also possible to configure the base station system so that each DU 20 performs at least part of the processing of S53. Specifically, each DU 20 may obtain the required margin for each UE and notify the RAN controller 40 of the obtained result. In this case, the RAN controller 40 receives notification from each DU 20, obtains the necessary margin for each scheduler (DU), finally determines the margin to be assigned to each DU, and performs the processing of S54 in the same manner as in the above embodiment. Also, each DU 20 may obtain not only the required margin for each UE but also the required margin for each DU, and notify the RAN controller 40 thereof. In this case, the RAN controller 40 can receive notification from each DU 20 and finally determine the margin to be assigned to each DU, and can perform the processing of S54 as in the above-described embodiment.

The wireless communication device according to the above-described embodiments can be realized by a computer program for causing a computer to function as a wireless communication device. The computer program can be stored in a computer-readable storage medium and distributed, or can be distributed via a network.

10: CU, 20: DU, 21: Scheduler, 30: RU, 40: RAN Controller, 50: 5GC UPF, 60: 5GC CPF, 70: Edge Application, 101: CPU, 102: ROM, 103: RAM, 104: External Storage Device, 105: Communication Device

Claims (31)

A controller that controls radio resources used by a scheduler that performs scheduling for allocating radio resources to radio terminals,
For each of a plurality of schedulers included in each individual DU (Distributed Unit) , a specifying means for specifying the amount of radio resources required for each scheduler in a predetermined period based on the data amount and communication quality of radio communication by radio terminals in the same cell formed by one RU (Radio Unit), wherein each of the plurality of schedulers corresponds to one or more slices, and schedules radio resources for radio terminals that use the corresponding slices in the same cell formed by the one RU. said identifying means configured to:
allocation means for allocating the amount of radio resources identified by the identification means and a margin of radio resources available for scheduling to each of the plurality of schedulers;
A control device comprising: The specifying means is
determining the amount of radio resources required for each radio terminal in the predetermined period based on the data amount and communication quality of radio communication by each radio terminal in the cell;
The control device according to claim 1, wherein, for each scheduler, the total amount of radio resources required for one or more wireless terminals using the corresponding slice is obtained as the amount of radio resources required for the scheduler in the predetermined period. 3. The control apparatus according to claim 1, wherein the radio resources allocated to each of the plurality of schedulers by the allocation unit are used by each scheduler for the scheduling of radio terminals using corresponding slices. 4. The control device according to any one of claims 1 to 3, wherein the scheduling by each of the plurality of schedulers is performed using radio resources within a range obtained by adding the allocated margin to the allocated radio resources. further comprising determining means for determining the margin allocated by the allocation means to each of the plurality of schedulers;
The control device according to any one of claims 1 to 4, wherein the determining means allocates the remaining amount of radio resources obtained by subtracting the amount of radio resources necessary for each scheduler identified by the identifying means from the total amount of radio resources that can be allocated by the allocating means in the predetermined period, to the plurality of schedulers as the margin. 6. The control device according to claim 5, wherein the determining means allocates the remaining radio resources based on slices used by radio terminals in the cell and margin information predetermined for each slice. 7. The control device according to claim 5 or 6, wherein the determining means obtains a necessary margin for each of the plurality of schedulers based on the slices used by the radio terminals in the cell and margin information predetermined for each slice, and allocates the remaining radio resources according to the obtained necessary margin. 8. The control apparatus according to claim 7, wherein said determining means allocates said remaining radio resources based on the ratio of said required margins of said plurality of schedulers. The control device according to claim 7 or 8, wherein the required margin is obtained by summing required margins for one or more wireless terminals using corresponding slices in the cell. 10. The control device according to any one of claims 7 to 9, wherein the margin information indicates a required margin for each wireless terminal for the wireless terminal to use the corresponding slice. 10. The control device according to any one of claims 7 to 9, wherein the margin information is a coefficient value used for calculating a required margin for each wireless terminal for the wireless terminal to use the corresponding slice, and indicates a coefficient value to be multiplied by the amount of radio resources required for each wireless terminal in the predetermined period. The control device according to any one of claims 9 to 11, wherein the required margin for each wireless terminal is obtained based on a priority determined for slices used by the wireless terminal. 13. The control device according to any one of claims 9 to 12, wherein the required margin for each wireless terminal is obtained based on an allowable delay determined for slices used by the wireless terminal. 14. The control device according to any one of claims 9 to 13, wherein the required margin for each wireless terminal is obtained based on a priority determined for an operator that provides a scheduler that performs the scheduling for the wireless terminal. 15. The control device according to any one of claims 5 to 14, wherein the determining means determines a portion of the remaining radio resources as an overlapping margin to be redundantly allocated between schedulers so that the total amount of the margins allocated to the plurality of schedulers exceeds the amount of the remaining radio resources. further comprising an accumulation means for accumulating performance information indicating a past performance of overlapping scheduling between schedulers for radio resources corresponding to the overlap margin;
16. The control device according to claim 15, wherein said determining means determines said overlap margin according to said performance information accumulated by said accumulating means. 17. The control device according to claim 16, wherein the accumulation means acquires the scheduling results from each of the plurality of schedulers and accumulates the performance information based on the scheduling results of the plurality of schedulers. 18. The control device according to claim 16 or 17, wherein the determining means controls the amount of the overlapping margin to be allocated thereafter according to the amount of radio resources for which the scheduling was performed redundantly between schedulers in the past, indicated by the performance information accumulated by the accumulating means. 19. The control device according to any one of claims 16 to 18, wherein said determining means determines said overlapping margin between schedulers for each combination of schedulers among said plurality of schedulers. The plurality of schedulers includes first, second and third schedulers;
20. The control device according to claim 19, wherein said determining means makes the amount of said overlap margin for the combination of said first and second schedulers greater than the amount of said overlap margin for the combination of said first and third schedulers. 21. The control device according to claim 19 or 20, wherein the determining means controls the amount of the overlap margin for each combination of schedulers according to the priority determined for the slices corresponding to each scheduler used by the radio terminals in the cell. 22. The control device according to any one of claims 15 to 21, further comprising: setting means for setting, for the RU , a rule for using the margin allocated by the allocation means, the rule for preventing the radio resources allocated as the overlapping margin from being used simultaneously between schedulers. 23. The control device according to claim 22, wherein the setting means sets the rule so that the allocation of radio resources corresponding to the overlap margin by a scheduler corresponding to a slice with a high priority is prioritized over the allocation of radio resources corresponding to the overlap margin by a scheduler corresponding to a slice with a low priority, according to the priority determined for the slice corresponding to each scheduler used by the radio terminals in the cell. The setting means notifies the RU of the priority determined for each slice corresponding to each of the plurality of schedulers,
24. The control device according to claim 22 or 23, wherein when the scheduling is performed redundantly between two or more schedulers for the radio resources corresponding to the overlapping margins, which scheduler among the two or more schedulers should give priority to radio resource allocation is determined by the RU according to the notified priority. 25. The control device according to any one of claims 1 to 24, wherein the identifying means identifies the amount of radio resources required for each scheduler in the predetermined period from the current time, at least at one timing of each predetermined period and when setting slices for wireless terminals in the cell. 26. The control device according to any one of claims 1 to 25, wherein the predetermined period is a period in which the amount of data for wireless communication by the wireless terminals in the cell and the amount of fluctuation in wireless quality are equal to or less than a predetermined amount. The specifying means is
Acquiring the amount of uplink data transmitted from each wireless terminal in the cell by notification from each wireless terminal,
27. The control device according to any one of claims 1 to 26, wherein the amount of downlink data to be transmitted to each radio terminal within the cell is obtained from notifications from the plurality of schedulers. The specifying means is
Obtaining measurement results of communication quality by the RU as uplink communication quality for each wireless terminal in the cell,
28. The control device according to any one of claims 1 to 27, wherein measurement results of communication quality by each radio terminal are acquired as the downlink communication quality of each radio terminal in the cell. The RU and the DU constitute a base station system,
The RU is located at an antenna site of the base station system;
The control device according to any one of claims 1 to 28, wherein the control device is communicably connected to the base station system. A control method executed by a control device that controls radio resources used by a scheduler that performs scheduling for allocating radio resources to radio terminals, comprising:
For each of a plurality of schedulers included in each individual DU (Distributed Unit) , a specifying step of specifying the amount of radio resources required for each scheduler in a predetermined period based on the data amount and communication quality of radio communication by radio terminals in the same cell formed by one RU (Radio Unit) , wherein each of the plurality of schedulers corresponds to one or more slices, and schedules radio resources for radio terminals that use the corresponding slices in the same cell formed by the one RU. the identifying step configured to perform;
an allocation step of allocating, to each of the plurality of schedulers, the amount of radio resources specified in the specifying step and a margin of radio resources available for scheduling;
A control method comprising: A program for causing a computer included in a control device to execute the control method according to claim 30.

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