JP2021057784A - Control apparatus, control method, program, and base station - Google Patents

Abstract

To provide techniques for adaptively changing mapping of IP flows to radio bearers at a base station.SOLUTION: A mapping control apparatus obtains radio quality information indicating communication quality of radio communication by each UE in a cell formed by a base station. The mapping control apparatus controls a mapping function of the base station to map QoS (IP flow) corresponding to each UE in the cell of the base station to a DRB (radio bearer) of a type appropriate for a 5QI (quality indicator) set for the QoS flow. The mapping control apparatus further controls the mapping function to change the mapping of one or more QoS flows determined according to the 5QI on the basis of the obtained radio quality information.SELECTED DRAWING: Figure 8

Description

The present invention relates to a control device, a control method and a program for controlling the mapping of an IP flow to a wireless bearer, and a base station including the control device.

In the 5th generation (5G) mobile communication system standardized by the 3rd generation partnership project (3GPP), the service type is large capacity (eMBB: enhanced Mobile BroadBand) and ultra-reliable and low latency (URLLC: Ultra-Reliable and Low Latency). It is roughly divided into three types: Communications) and multiple connections (mMTC: massive Machine Type Communications), and each service request is different. Network slicing is being considered in order to provide services with different requirements economically and flexibly.

Further, in the 5G standard, as a QoS (Quality of Service) model, a model in which an IP packet is mapped to a QoS flow (IP flow) in a core network and a QoS flow is mapped to a wireless bearer in a base station is adopted. In this QoS model, QoS characteristics are individually associated with each QoS flow using a quality indicator called 5QI (5G Quality Indicator). This enables QoS control in IP flow units instead of call units as in LTE.

Uchino, Kai Toeda Takahashi, "NR Upper Layer Specifications in 5G", NTT DOCOMO Journal, Vol.26, No.3, November 2018.

In the above-mentioned QoS control, the QoS flow is fixedly mapped to the wireless bearer according to the 5QI. However, when wireless resources are wasted by a specific wireless terminal in order to satisfy the QoS characteristics corresponding to 5QI, for example due to deterioration of wireless communication quality, the QoS characteristics are changed for all the wireless terminals in the cell of the base station. It can be difficult to maintain (guarantee throughput). In such cases, it is necessary to be able to control the mapping of QoS flows to wireless bearers so that the associated QoS characteristics can be maintained for as many wireless terminals as possible in the cell.

The present invention has been made in view of the above-mentioned problems. An object of the present invention is to provide a technique for adaptively changing the mapping of an IP flow (QuoS flow) to a wireless bearer in a base station.

The control device according to one aspect of the present invention is a control device that controls a mapping function of a base station that maps an IP flow for communication between a wireless terminal and a core network to a wireless bearer, and is formed by the base station. The quality of the acquisition means for acquiring the wireless quality information indicating the communication quality of the wireless communication by each wireless terminal in the cell and the IP flow corresponding to each wireless terminal in the cell are set for the IP flow. Map to the type of radio bearer according to the index and change the mapping defined according to the quality index for one or more IP flows based on the radio quality information acquired by the acquisition means. It is characterized by including a control means for controlling the mapping function and a notification means for notifying the mapping function of mapping information for control by the control means.

According to the present invention, it is possible to adaptively change the mapping of the IP flow (Quos flow) to the wireless bearer at the base station.

The figure which shows the communication network configuration example. A block diagram showing a hardware configuration example of a mapping control device. A block diagram showing a functional configuration example of a mapping control device. The figure which shows the example of mapping of IP flow to a wireless bearer. The figure which shows the example of mapping of IP flow to a wireless bearer. The figure which shows the example of the correspondence relation between 5QI and QoS characteristic. A sequence diagram showing a communication and processing procedure between a mapping control device and a base station. The flowchart which shows the processing procedure by a mapping control device.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more of the plurality of features described in the embodiments may be arbitrarily combined. In addition, the same or similar configuration will be given the same reference number, and duplicate description will be omitted.

<Communication system configuration>
FIG. 1 is a diagram showing a configuration example of a communication system according to an embodiment of the present invention. In the present embodiment, a 5G mobile communication system called NR (New Radio) according to the 3GPP standard is assumed, but the present invention may be applied to a mobile communication system according to another communication standard. As shown in FIG. 1, the communication system of the present embodiment includes a core network (CN) 40 including a mapping control device 10, a base station 20, and an UPF (User Plane Function) 30. UPF30 is a data processing function group of a 5G core network (5GC: 5G Core). The base station 20 is also referred to as gNB in the 5G standard.

The base station 20 provides a service to each UE by performing wireless communication with one or more wireless terminals in a cell formed by the base station. In the example of FIG. 1, UEs # 1 to # 4 are exemplified as wireless terminals that access the base station 20. UEs # 1 to # 4 can access the CN40 via the base station 20 and can access an external network (Internet, etc.) via the CN40. The base station 20 may be a base station capable of providing a plurality of slices (services), that is, the base station 20 may be shared by the plurality of slices. For example, multiple slices corresponding to mMTC, URLLC and eMBB as service types may be generated and those slices may be provided within the cell formed by base station 20.

The mapping control device 10 is an example of a control device that controls the mapping function of the base station 20 that maps the IP flow for communication between the UE (wireless terminal) and the CN40 to the wireless bearer. The base station 20 of the present embodiment implements the function of the SDAP (Service Data Adaptation Protocol) layer defined in the 5G standard as such a mapping function. In the present embodiment, the mapping control device 10 is communicably connected to the base station 20. In this case, the mapping control device 10 may be included in, for example, an O-RAN (Open RAN) RIC (RAN Intelligent Controller). Further, the mapping control device 10 may be mounted on the base station 20 as a part of its function. That is, the base station 20 may be configured as a base station having a mapping function (SDAP layer function) and including a mapping control device 10.

<Configuration of mapping control device>
As an example, the mapping control device 10 has a hardware configuration as shown in FIG. Specifically, the mapping control device 10 includes 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 mapping control device 10, for example, a program stored in any one of the ROM 102, the RAM 103, and the external storage device 104 that realizes each function of the mapping control device 10 is executed by the CPU 101. The CPU 101 may be replaced by one or more processors such as an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), and a DSP (digital signal processor).

The communication device 105 is a communication interface for communicating with an external device such as a base station 20 having a mapping function (mapping unit 22 in FIG. 7) to be controlled under the control of the CPU 101. The mapping control device 10 may have a plurality of communication devices 105 having different connection destinations.

The mapping control device 10 may be provided with dedicated hardware for executing each function described later, or a part of the mapping control device 10 may be executed by the hardware and the other part may be executed by the computer running the program. .. Also, all functions may be performed by a computer and a program.

The base station 20 may also have a hardware configuration as shown in FIG. As the communication device 105, the base station 20 may include a wireless communication interface for wireless communication with the UE, in addition to a communication interface for communication with an external device such as the UPF 30 of the CN40 and the mapping control device 10.

FIG. 3 is a block diagram showing a functional configuration example of the mapping control device 10. The mapping control device 10 of the present embodiment includes an information acquisition unit 31, a control unit 32, an information notification unit 33, and an information storage unit 34. 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.

The information acquisition unit 31 acquires wireless quality information indicating the communication quality of wireless communication by each UE in the cell formed by the base station 20. The information acquisition unit 31 acquires such radio quality information by a notification transmitted from the base station 20, and stores the acquired information in the information storage unit 34.

The control unit 32 generates mapping information for mapping the IP flow to the wireless bearer, and provides the generated mapping information to the base station 20 to have a mapping function (mapping unit 22 in FIG. 7). To control. Specifically, the control unit 32 maps the IP flow corresponding to each UE in the cell of the base station 20 to a radio bearer of the type corresponding to the quality index set for the IP flow. Control the mapping function. The control unit 32 further controls the mapping function so as to change the mapping determined according to the quality index for one or more IP flows based on the radio quality information acquired by the information acquisition unit 31.

The information notification unit 33 notifies the mapping function of the base station 20 of the mapping information for control by the control unit 32 generated by the control unit 32. The information storage unit 34 corresponds to a database provided in a storage device (for example, RAM 103 or external storage device 104), and stores information acquired by the information acquisition unit 31 and mapping information generated by the control unit 32. Used.

<IP flow mapping control>
Next, with reference to FIGS. 4 to 6, the IP flow mapping control performed by the control unit 32 of the mapping control device 10 in the present embodiment will be described. In the 5G standard, the IP flow is also called a QoS flow. In the examples of FIGS. 4 and 5, QoS flows # 1 to # 4 are established as IP flows for communication between UEs # 1 to # 4 and CN40 (UPF30), respectively.

By setting a quality indicator called 5QI (5G Quality Indicator) in the 5G standard for each QoS flow, QoS characteristics corresponding to 5QI are individually associated with each QoS flow. This enables QoS control in IP flow units. FIG. 6 shows an example of the correspondence between such 5QI and QoS characteristics. As shown in FIG. 6, each 5QI value is associated with QoS characteristics such as resource type, priority level, packet delay budget, and packet error rate. In particular, as a resource type, GBR (Guaranteed Bit Rate) that guarantees throughput (bit rate) or non-GBR (non-GBR) that does not guarantee throughput is associated with each 5QI value.

The function (mapping function) of the SDAP layer of the base station 20 has a function of mapping a QoS flow to a wireless bearer based on such 5QI. When the base station 20 is configured to provide access to a plurality of slices in the cell, the mapping function of the base station 20 includes 5QI and NSSAI (Network Slice Selection Assistance Information) which is a slice identifier. ) And, the QoS flow is mapped.

In the examples of FIGS. 4 and 5, each QoS flow is mapped to a radio bearer (DRB: Data Radio Bearer) for radio communication in the radio section between the base station 20 and each UE based on such 5QI. Has been done. As a result, each QoS flow is transmitted in the radio section between the base station 20 and each UE using the mapped radio bearer. Normally, a quality of service flow is fixedly mapped to a DRB (radio bearer) of a type corresponding to a 5QI (quality index) set for the quality of service flow. For example, in the example of FIG. 4, the QoS flows # 1 to # 4 are set with 5QI # 2, which is one of the quality indicators indicating that the throughput should be guaranteed. The QoS flows # 1 to # 4 are mapped to DRB # 1 to # 4 of the type that guarantees throughput (GBR type) according to the 5QI # 2, respectively. Two or more QoS flows may be mapped to one DRB.

However, as described above, when the QoS flow is fixedly mapped to the DRB according to 5QI, the mapping of the QoS flow may be adaptively changed according to the wireless communication quality in the cell of the base station 20 and the like. Can not. In this case, for example, when wireless resources are wasted by a specific UE due to deterioration of wireless communication quality in the cell of the base station 20, it is effective in a situation where the wireless resources to be allocated to the GRB type DRB are insufficient. Can't deal with. As a result, due to lack of radio resources in the radio section, it may not be possible to maintain overall throughput for each DRB type QoS flow.

Therefore, in the present embodiment, as described above, the QoS flow is not fixedly mapped to the DRB according to the 5QI, but is determined according to the 5QI based on the communication quality of the wireless communication by each UE. Allows you to change the mapping. For this purpose, the control unit 32 of the mapping control device 10 changes the mapping determined according to 5QI (quality index) for one or more IP flows based on the radio quality information acquired by the information acquisition unit 31. The mapping function of the base station 20 is controlled so as to do so. Specifically, the control unit 32 maps one or more QoS flows to the GBR type (first type) DRB that guarantees throughput in wireless communication using the DRB based on the radio quality information. Control to change between mapping and mapping of non-GBR type (second type) to DRB that does not guarantee throughput.

FIG. 5 shows one or more of QoS flows # 1 to # 4 when the radio resources that need to be allocated to the GBR type DRB in the cell of the base station 20 are insufficient (that is, the throughput cannot be guaranteed). An example of changing the mapping to DRB for (some) QoS flows is shown. In this example, the control unit 32 controls to change the mapping of one or more QoS flows of the GBR type to the mapping of the non-GBR type based on the radio quality information.

Specifically, for the QoS flow # 3 corresponding to UE # 3, the mapping to the GBR type DRB # 3 is changed to the mapping to the non-GBR type DRB # 5. Further, regarding the QoS flow # 4 corresponding to UE # 4, the mapping to the GBR type DRB # 4 is changed to the mapping to the non-GBR type DRB # 6. This makes it possible to maintain the throughput for the QoS flows # 1 and # 2 corresponding to UEs # 1 and # 2.

<Processing procedure>
Next, the procedure of the processing executed by the mapping control device 10 and the base station 20 will be described with reference to FIGS. 7 and 8. FIG. 7 is a sequence diagram showing a communication and processing procedure between the mapping control device 10 and the base station 20. FIG. 8 is a flowchart showing a processing procedure by the mapping control device 10. Note that S81 corresponds to S71, S82 and S83 correspond to S72, and S84 corresponds to S73.

As shown in FIG. 7, the base station 20 has an information transmitting unit 21, a mapping unit 22, and an information receiving unit 23 as functional configurations. In the present embodiment, the base station 20 is referred to as a logical node called a DU (Distributed Unit) having a function of a lower layer among the functions of the base station, and a CU (Central Unit) having a function of a higher layer. It consists of logical nodes. In this case, the information transmitting unit 21 corresponds to the DU, the mapping unit 22 corresponds to the function of the SDAP layer of the CU, and the information receiving unit 23 corresponds to the function of the RRC (Radio Resource Control) layer of the CU.

The processes of S71 to S75 can be periodically executed at an arbitrary cycle. First, in S71 (S81), the mapping control device 10 (information acquisition unit 31) acquires the radio quality information of each UE in the cell of the base station 20 by the notification transmitted from the information transmission unit 21. The information transmission unit 21 transmits a notification including wireless communication information to the mapping control device 10 at an arbitrary cycle. When the base station 20 is configured to provide access to a plurality of slices in the cell, the information transmission unit 21 generates radio quality information of the UE accessing each slice for each slice. Then, it is transmitted to the mapping control device 10.

The information acquisition unit 31 also includes information on each QoS flow established between each UE in the cell of the base station 20 and the UPF 30 (including the 5QI value included in each QoS flow) of the base station 20. Or it can be obtained from UPF30. In addition, the information acquisition unit 31 can also acquire terminal number information indicating the number of UEs connected to the base station in the cell of the base station 20 as necessary.

Next, in S72 (S82 and S83), the mapping control device 10 (control unit 32) generates mapping information for control of the mapping unit 22 based on the radio quality information acquired in S71 (S81). Specifically, in S82, the control unit 32 sets the QoS flow corresponding to each UE in the cell of the base station 20 to the type (GBR type or non-GBR type) corresponding to the 5QI set for the QoS flow. ) Is controlled to be mapped to the DRB. The control unit 32 generates mapping information for this control and stores it in the information storage unit 34.

After that, in S83, the control unit 32 needs a DRB mapping change process for changing the mapping determined according to 5QI for one or more QoS flows based on the wireless communication information acquired in S71 (S81). Do according to. When the base station 20 is configured to provide access to a plurality of slices in the cell, the control unit 32 accesses the slice that provides the service that guarantees the throughput among the plurality of slices. For the QoS corresponding to one or more UEs to be used, the change process is performed so as to change the mapping defined according to 5QI.

Specifically, when the control unit 32 determines that the radio resources required for the GRB type DRB are insufficient in the cell of the base station 20 based on the radio quality information, the control unit 32 responds to 5QI for one or more QoS flows. Control to change the defined mapping. The control unit 32 performs such control by reflecting such a change in mapping in the mapping information stored in the information storage unit 34.

In S83, the control unit 32 determines whether or not the radio resources required for the GRB type DRB are insufficient in the cell of the base station 20 based on the terminal number information acquired as described above. May be good. In this case, the control unit 32 may control to change the mapping determined according to 5QI for one or more QoS flows according to the determination result.

Further, in S83, the control unit 32 may perform a process of predicting the amount of radio resources used by each UE in the cell of the base station 20 based on the information notified from the base station 20. In this case, the control unit 32 may control to change the mapping determined according to 5QI for one or more QoS flows based on the prediction result.

In the DRB mapping change process in S83, the UE to be changed in the corresponding QoS flow mapping may be determined based on the following criteria. For example, the control unit 32 maps the QoS flow corresponding to each UE from the mapping to the GBR type DRB to the non-GBR type DRB in ascending order of the priority set in advance for each UE in the cell of the base station 20. It may be controlled to change to the mapping to. This makes it possible to prioritize and maintain throughput for UEs with high priority.

Alternatively, the control unit 32 converts the QoS flow corresponding to each UE from the mapping to the GBR type DRB to the non-GBR type DRB in the order of the worse communication quality indicated by the radio quality information for each UE in the cell of the base station 20. It may be controlled to change to the mapping to. This makes it less likely that overall throughput cannot be maintained for each DRB-type QoS flow due to the allocation of more radio resources to the DRB used by UEs with poor communication quality. can do.

When the processing of S72 (S82 and S83) is completed, in S73 (S84), the mapping control device 10 (information notification unit 33) transmits the mapping information generated in S72 and stored in the information storage unit 34 to the base station 20. Notify to. This mapping information is received by the information receiving unit 23 of the base station 20. The information notification unit 33 may notify the base station 20 of the mapping information only when the mapping information has changed from the previous processing as a result of the processing of S72.

In the base station 20, when the information receiving unit 23 receives the notification of the mapping information from the mapping control device 10, the information receiving unit 23 notifies the mapping unit 22 of the mapping setting based on the notified mapping information in S74. When the mapping unit 22 receives the mapping setting from the information receiving unit 23, the mapping unit 22 updates the DRB mapping according to the mapping setting in S75. In this way, the control unit 32 of the mapping control device 10 controls the DRB mapping by the mapping unit 22.

As described above, in the mapping control device 10 of the present embodiment, the information acquisition unit 31 acquires radio quality information indicating the communication quality of wireless communication by each UE in the cell formed by the base station 20. The control unit 32 maps the QoS (IP flow) corresponding to each UE in the cell of the base station 20 to a DRB (wireless bearer) of a type corresponding to the 5QI (quality index) set for the QoS flow. The mapping unit 22 (mapping function) of the base station 20 is controlled so as to perform the above. The control unit 32 further controls the mapping function so as to change the mapping determined according to 5QI (quality index) for one or more QoS flows based on the acquired radio quality information.

According to this embodiment, the mapping of the QoS flow (IP flow) of the DRB can be adaptively changed in the base station 20, and the QoS of each QoS flow can be changed. Specifically, it is possible to change the QoS of each QoS flow based on the wireless communication quality of each UE in the cell of the base station 20. This makes it possible to perform more flexible QoS control as the QoS control for each QoS flow. Further, since it is possible to change the QoS for each UE by changing the DRB mapping in the base station 20, the QoS control for each QoS flow is changed only in the RAN (radio access network) without going through the CN40. Will be possible.

[Other Embodiments]
The control device (mapping control device) according to the above-described embodiment can be realized by a computer program for operating the computer as a control device. The computer program is stored in a computer-readable storage medium and can be distributed, or can be distributed via a network.

The invention is not limited to the above-described embodiment, and various modifications and changes can be made within the scope of the gist of the invention.

10: Mapping control device, 20: Base station, 30: UPF, 40: CN (core network), 31: Information acquisition unit, 32: Control unit, 33: Information notification unit, 34: Information storage unit

Claims (16)

A control device that controls the mapping function of a base station that maps the IP flow for communication between a wireless terminal and a core network to a wireless bearer.
An acquisition means for acquiring wireless quality information indicating the communication quality of wireless communication by each wireless terminal in the cell formed by the base station, and
The IP flow corresponding to each wireless terminal in the cell is mapped to a wireless bearer of a type corresponding to the quality index set for the IP flow, and the wireless quality information acquired by the acquisition means is used. Based on the control means that controls the mapping function so as to change the mapping defined according to the quality index for one or more IP flows.
A notification means for notifying the mapping function of mapping information for control by the control means, and
A control device comprising. Based on the radio quality information, the control means maps the mapping for one or more IP flows to a first-type wireless bearer that guarantees throughput in wireless communication using the wireless bearer, and wirelessly. The control device according to claim 1, wherein in wireless communication using a bearer, control is performed so as to change between the mapping to the second type wireless bearer that does not guarantee the throughput. The quality index indicates that throughput should be guaranteed or not.
The one or more IP flows are IP flows that are mapped to the first type wireless bearer according to the quality index.
2. The control means according to claim 2, wherein the control means controls to change the mapping of the one or more IP flows to the mapping to the second type radio bearer based on the radio quality information. Control device. When the control means determines that the radio resources required for the first type radio bearer are insufficient in the cell based on the radio quality information, the control means determines one or more IP flows according to the quality index. The control device according to claim 2 or 3, wherein the control device is controlled so as to change the assigned mapping. The acquisition means further acquires terminal number information indicating the number of wireless terminals connected to the base station in the cell.
When the control means determines that the radio resources required for the first type wireless bearer are insufficient in the cell based on the terminal number information, the control means determines one or more IP flows according to the quality index. The control device according to any one of claims 2 to 4, wherein the control device is controlled so as to change the assigned mapping. In the change of the mapping, the control means maps the IP flow corresponding to each wireless terminal to the first type wireless bearer in ascending order of priority set for each wireless terminal in the cell. The control device according to any one of claims 2 to 5, wherein the control device is controlled so as to change to the mapping to the second type wireless bearer. In the change of the mapping, the control means transfers the IP flow corresponding to each wireless terminal to the first type wireless bearer in the order of poor communication quality indicated by the wireless quality information for each wireless terminal in the cell. The control device according to any one of claims 2 to 6, wherein the mapping is controlled to change from the mapping to the mapping to the second type wireless bearer. The control device according to any one of claims 1 to 7, wherein the acquisition means acquires the radio quality information by a notification transmitted from the base station. Further provided with a prediction means for predicting the amount of radio resources used by each radio terminal in the cell based on the information notified from the base station.
The control means according to claims 1 to 8, wherein the control means controls the one or more IP flows to change the mapping determined according to the quality index based on the prediction result by the prediction means. The control device according to any one item. The base station is configured to provide access to a plurality of slices within the cell.
The control means changes the mapping determined according to the quality index for the IP flow corresponding to one or more wireless terminals accessing the slice that provides the service that guarantees the throughput among the plurality of slices. The control device according to any one of claims 1 to 9, wherein the control device is characterized in that. The control device according to any one of claims 1 to 10, wherein the mapping function is implemented in the base station as a function of the SDAP (Service Data Adaptation Protocol) layer. The control device according to any one of claims 1 to 11, wherein the control device is communicably connected to the base station. The control device according to claim 12, wherein the control device is included in an O-RAN (Open RAN) RIC (RAN Intelligent Controller). A base station having the mapping function and including the control device according to any one of claims 1 to 11. A control method executed by a control device that controls a base station mapping function that maps an IP flow for communication between a wireless terminal and a core network to a wireless bearer.
An acquisition process for acquiring wireless quality information indicating the communication quality of wireless communication by each wireless terminal in the cell of the base station, and
The IP flow corresponding to each wireless terminal in the cell is mapped to a wireless bearer of a type corresponding to the quality index set for the IP flow, and the wireless quality information acquired in the acquisition process is used. Based on, a control step that controls the mapping function to change the mapping defined according to the quality index for one or more IP flows.
A notification process for notifying the mapping function of mapping information for control by the control process, and
A control method comprising. A program for causing a computer included in a control device to execute each step of the control method according to claim 15.

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