WO2019186852A1

WO2019186852A1 - Radio communication system, radio control device, and radio resource control method

Info

Publication number: WO2019186852A1
Application number: PCT/JP2018/013049
Authority: WO
Inventors: 忠人富川; 大出　高義; 高木　淳一
Original assignee: 富士通株式会社
Priority date: 2018-03-28
Filing date: 2018-03-28
Publication date: 2019-10-03

Abstract

A first radio control device has a transmission unit (140) that notifies a second radio control device of a request regarding a first radio resource for transmitting in accordance with the control of the first radio control device. The second radio control device has a reception unit (140) that receives the request regarding the first radio resource, a management unit (125) that controls the first radio resource and a second radio resource, said second radio resource being used for radio communication by a radio device that connects to the second radio control device, a notification unit (140) that notifies the first radio control device of information regarding the first radio resource controlled by the management unit, and a scheduling unit (123) that assigns a third radio resource to communication of the second radio control device and a radio terminal device, said third radio resource being at least one portion of the second radio resource controlled by the management unit. The radio device has a radio communication unit (240) that uses the third radio resource to perform radio communication with the radio device.

Description

Radio communication system, radio control apparatus, and radio resource control method

The present invention relates to a wireless communication system, a wireless control device, and a wireless resource control method.

In recent years, base station devices provided in wireless communication systems have been separated into wireless control devices such as BBU (Base Band Unit) and wireless devices such as RRH (Remote Radio Head). It may be connected by an interface such as CPRI (Common Public Radio Interface). Also, in 3GPP (3rd Generation Partnership Project), gNB, which is a base station device of the 5th generation wireless communication system (5G), and CU (Central Unit), which is a radio controller that performs various controls, transmit and receive signals wirelessly. It is considered that the CU is connected to the DU (Distributed Unit), which is a wireless device that performs the communication, and the CU and the DU are connected by the F1 interface.

By separating the functions of the base station device in this way, for example, a plurality of DUs are connected to one CU, and the DUs are distributed to construct a wireless communication system that covers a large area at a low cost. Is possible. On the other hand, for example, by connecting a plurality of CUs provided for each service to one DU, various wireless communication services can be efficiently provided. Furthermore, it is also considered to connect a CU and a DU in many-to-many connection instead of the above-described one-to-many connection or many-to-one connection.

By the way, in general, the functions of the base station apparatus include processing of PDCP (Packet Data Convergence Protocol) layer, RLC (Radio Link Control) layer, MAC (Media Access Control) layer and PHY (Physical) layer in order from the upper layer. In 5G, it is discussed to introduce processing of an SDAP (Service Data Adaptation Protocol) layer, which is an upper layer of the PDCP layer, into the function of the user plane (U plane).

When the base station apparatus (gNB) is functionally separated into CUs and DUs, there are various options as to which layer is separated into CUs and DUs. In 5G wireless communication systems, currently, HLS (High Layer Split) that separates CU and DU between relatively higher layers and LLS (Low Layer Split) that separates CU and DU between relatively lower layers. ) And will be introduced.

Specifically, for example, as shown in FIG. 1, in HLS, a CU and a DU are separated between the PDCP layer and the RLC layer, the processing unit of the RRC layer and the PDCP layer is included in the CU, and the RLC layer and the MAC are included in the DU. Layer and PHY layer processing units are included. On the other hand, in LLS, the CU and DU are separated between the MAC layer and the PHY layer, the CU includes an RRC layer, a PDCP layer, an RLC layer, and a MAC layer processing unit, and the DU includes a PHY layer processing unit. In addition, an LLS in which the inside of the PHY layer is divided into an upper layer and a lower layer and the CU and DU are separated between the upper layer and the lower layer is also considered.

As described above, when gNB is functionally separated by LLS, a processing unit of the MAC layer is included in the CU. The MAC layer includes a process such as scheduling for allocating radio resources that can be used for radio transmission from the DU to the radio terminal apparatus. Therefore, when the functions are separated by the LLS, the DU (radio apparatus) and the radio terminal A CU (Radio Control Unit) executes scheduling of radio communication between apparatuses.

At this time, in a many-to-one connection or a many-to-many connection configuration in which a plurality of CUs are connected to one DU, there is a problem in that overlapping allocation of radio resources may occur due to scheduling by a plurality of CUs. That is, since a plurality of CUs each perform scheduling of radio communication from one DU to a terminal device, radio resources already allocated by other CUs may be allocated to communication redundantly. As a result, it becomes difficult for the DU to normally transmit a signal to the terminal device, and data loss and delay may occur.

The disclosed technology has been made in view of the above points, and an object thereof is to provide a radio communication system, a radio control apparatus, and a radio resource control method capable of avoiding redundant allocation of radio resources during scheduling. To do.

In one aspect, a wireless communication system disclosed in the present application is a wireless communication system including a first wireless control device, a second wireless control device, a wireless device, and a wireless terminal device, wherein the first wireless control device The apparatus includes a transmission unit that notifies the second radio control apparatus of a request related to a first radio resource for communication according to the control of the first radio control apparatus, and the second radio control apparatus A receiving unit that receives a request regarding the first radio resource notified from the first radio control device, the first radio resource, and the radio device connected to the second radio control device. A management unit that controls a second radio resource used for radio communication, a notification unit that notifies the first radio control apparatus of information related to the first radio resource controlled by the management unit, and the second radio resource Nothing A scheduling unit that allocates a third radio resource that is at least part of the second radio resource controlled by the management unit for communication between the control device and the radio terminal device; And a wireless communication unit that wirelessly communicates with the wireless device using the third wireless resource.

According to one aspect of the wireless communication system, the wireless control device, and the wireless resource control method disclosed in the present application, there is an effect that it is possible to avoid overlapping assignment of wireless resources during scheduling.

FIG. 1 is a diagram illustrating a specific example of CU / DU function separation. FIG. 2 is a diagram illustrating an example of the wireless communication system according to the first embodiment. FIG. 3 is a block diagram showing a configuration of the CU according to the first embodiment. FIG. 4 is a block diagram showing a configuration of the DU according to the first embodiment. FIG. 5 is a sequence diagram showing an operation at the time of IF setting. FIG. 6 is a sequence diagram showing an operation at the time of regular resource arbitration. FIG. 7 is a sequence diagram showing an operation at the time of temporary resource arbitration. FIG. 8 is a diagram illustrating an example of a change in the amount of radio resources. FIG. 9 is a block diagram showing a configuration of a CU according to the second embodiment. FIG. 10 is a sequence diagram showing an operation when the master is changed. FIG. 11 is a sequence diagram illustrating a specific example of the master change.

Hereinafter, embodiments of a wireless communication system, a wireless control device, and a wireless resource control method disclosed in the present application will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment.

(Embodiment 1)
FIG. 2 is a diagram illustrating an example of the wireless communication system according to the first embodiment. In the wireless communication system shown in FIG. 2, a plurality of CUs (Central Units) 100a to 100c are connected to a core network, and the CUs 100a to 100c and a plurality of DUs (Distributed Units) 200a to 200c are many-to-many connected. ing. The DUs 200a to 200c communicate wirelessly with a terminal device (UE: User Equipment) 20.

The core network includes UPF (User Plane Function) 11, AMF (Access and Mobility Management Function) 12, SMF (Session Management Function) 13, PCF (Policy Control Function) 14, AUSF (Authentication Server Function) 15, and UDM (Unified). Data Management) 16 is arranged.

The UPF 11 is a device that controls the user plane, and executes routing and transfer of user data. The AMF 12 is a device that controls the control plane, and terminates the control plane in a radio access network (RAN). The SMF 13 performs session management. The PCF 14 provides policy rules related to the control plane. The AUSF 15 performs an authentication process for the UE 20. The UDM 16 stores subscriber information and the like.

The CUs 100a to 100c are radio control apparatuses that are connected to the UPF 11 and the AMF 12 of the core network and control radio communication between the DUs 200a to 200c and the UE 20 that are connected to each other. That is, in the example shown in FIG. 2, the CU 100a controls wireless communication by the DU 200a, the CU 100b controls wireless communication by the

DUs

200a and 200b, and the CU 100c controls wireless communication by the

DUs

200a and 200c. Each of the CUs 100a to 100c may be a wireless control device that controls transmission / reception of data of different services, or may be a wireless control device managed by different communication carriers.

In this embodiment, since the functions are separated into the CUs 100a to 100c and the DUs 200a to 200c by the LLS, the CUs 100a to 100c execute MAC layer scheduling. That is, the CUs 100a to 100c allocate radio resources to radio communication between the DUs 200a to 200c and the UE 20 to be connected. Any one of the CUs 100a to 100c connected to the DU 200a is a master CU (hereinafter also simply referred to as “master”) regarding the DU 200a, and the remaining two are CUs that are slaves (hereinafter also simply referred to as “slave”). It becomes. The master executes arbitration (control) of radio resources used by the CUs 100a to 100c for scheduling, and controls the radio resources available to the respective CUs 100a to 100c for scheduling. Therefore, the slave performs scheduling of radio communication by the DU 200a using the radio resource instructed by the master. The configuration and operation of the CUs 100a to 100c will be described in detail later. For example, an operation of selecting the UE 20 with which the CU 100a communicates and selecting (determining) a radio resource to be used for radio communication with the selected UE 20 is referred to as “scheduling”. On the other hand, for example, the total radio resources used when the CU 100a performs radio communication with one or more UEs 20 and the total radio resources used when the other CUs 100b and CU 100c perform radio communication with one or more UEs 20 are controlled. The operation to be managed is called “resource control”.

The DUs 200a to 200c are wireless devices that perform wireless communication with the UE 20 according to control by the connected CUs 100a to 100c. That is, in the example shown in FIG. 2, the DU 200a is controlled by the CUs 100a to 100c, the DU 200b is controlled by the CU 100b, and the DU 200c is controlled by the CU 100c.

Since the DU 200a is controlled by the CUs 100a to 100c, the data addressed to the UE 20 is wirelessly transmitted according to the scheduling performed by each of the CUs 100a to 100c. That is, the DU 200a wirelessly transmits data to the UE 20 using the radio resources allocated by each of the CUs 100a to 100c. At this time, since arbitration of radio resources is performed by the master, duplicate allocation of radio resources by the CUs 100a to 100c does not occur, and the DU 200a wirelessly transmits data as scheduled by all the CUs 100a to 100c. Can do.

The UE 20 performs wireless communication with the DUs 200a to 200c. In FIG. 2, only one UE 20 is illustrated, but the wireless communication system may include a plurality of UEs 20, and data destined for each UE 20 is transmitted according to scheduling by the CUs 100a to 100c. 200c is wirelessly transmitted. Similarly, data transmitted from a plurality of UEs 20 may be wirelessly transmitted from each UE 20 in accordance with scheduling by the CUs 100a to 100c.

FIG. 3 is a block diagram illustrating a configuration of the CU 100 according to the first embodiment. The CU 100 corresponds to the CUs 100a to 100c shown in FIG. 3 includes a network interface unit (hereinafter abbreviated as “network I / F unit”) 110, a processor 120, a memory 130, and a LAN (Local Area Network) communication interface unit (hereinafter “LAN communication I / F unit”). 140).

The network I / F unit 110 is connected to the UPF 11 and the AMF 12 of the core network, and transmits / receives data. Specifically, the network I / F unit 110 transmits / receives user data to / from the UPF 11 and transmits / receives control data to / from the AMF 12.

The processor 120 includes, for example, a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), or a DSP (Digital Signal Processor), and performs overall control of the CU 100. Specifically, the processor 120 includes a PDCP processing unit 121, an RLC processing unit 122, a MAC processing unit 123, a resource control unit 124, and a master management unit 125.

The PDCP processing unit 121 executes PDCP layer processing such as data ordering and header compression. That is, the PDCP processing unit 121 performs PDCP layer processing on the transmission data acquired from the UPF 11 or the AMF 12 and outputs the transmission data to the RLC processing unit 122. In addition, the PDCP processing unit 121 acquires received data from the RLC processing unit 122, and executes PDCP layer processing on the received data.

The RLC processing unit 122 executes RLC layer processing such as retransmission control. That is, the RLC processing unit 122 acquires transmission data from the PDCP processing unit 121, and performs RLC layer processing on the transmission data. In addition, the RLC processing unit 122 acquires received data from the MAC processing unit 123, and performs RLC layer processing on the received data.

The MAC processing unit 123 executes MAC layer processing such as scheduling and retransmission control. That is, the MAC processing unit 123 acquires transmission data from the RLC processing unit 122, and performs MAC layer processing on the transmission data. In addition, the MAC processing unit 123 acquires received data from the DU 200 via the LAN communication I / F unit 140, and executes a MAC layer process on the received data. The MAC processing unit 123 is also a scheduling unit that executes scheduling.

The MAC processing unit 123 uses a radio resource such as a time or a frequency band specified by the resource control unit 124 when executing scheduling for allocating radio resources for radio communication between the DU 200 and the UE 20.

The resource control unit 124 controls radio resources that the MAC processing unit 123 can use in scheduling. Specifically, the resource control unit 124 designates radio resources allocated by the master CU to the CU 100 as radio resources that can be used for scheduling. Further, the resource control unit 124 monitors the allocation status of radio resources in the MAC processing unit 123, and responds with an amount of radio resources necessary for scheduling when inquired from the master management unit 125. Furthermore, the resource control unit 124 determines whether or not a shortage of radio resources has occurred in the scheduling, and if a shortage of radio resources has occurred, reports that fact to the master management unit 125.

The master management unit 125 manages master CU information for each DU 200 to which the CU 100 is connected. Then, when the CU 100 is a master, the master management unit 125 requests a slave connected to the same DU 200 to periodically report the amount of necessary radio resources. When the amount of necessary radio resource is reported from the slave, the master management unit 125 controls the radio resource used by each CU including the CU 100 and notifies each slave of the control result as information on the radio resource.

On the other hand, when the CU 100 is a slave, the master management unit 125 makes an inquiry to the resource control unit 124 for information on the amount of radio resources necessary for scheduling and the usage status of radio resources in response to a request from the master, The response from the control unit 124 is reported to the master. Further, when the resource control unit 124 reports that a shortage of radio resources has occurred, the master management unit 125 requests the master to increase the distribution of radio resources. Note that the master management unit 125 may request the master to reduce the allocation of radio resources when the resource control unit 124 reports that surplus radio resources have occurred. Furthermore, when radio resources used based on radio channel quality such as reception power or reception quality notified from the UE 20 are not suitable for radio communication, the master management unit 125 changes the radio resources to the master. You may request. In short, the master management unit 125 executes control regarding radio resources.

Although omitted in FIG. 3, the processor 120 may have an SDAP (Service Data Adaptation Protocol) processing unit. The SDAP processing unit maps a flow in which communication conditions (for example, QoS (Quality of Service)) are set to a bearer.

The memory 130 includes, for example, RAM (Random Access Memory) or ROM (Read Only Memory), and stores information used by the processor 120 to execute processing.

LAN communication I / F unit 140 is connected to other CU 100 and DU 200 to transmit and receive data. Specifically, the LAN communication unit I / F unit 140 periodically transmits / receives a request or response for the amount of required radio resources to / from other CUs 100, or notifies the allocation of radio resources in each CU 100. Send and receive. Further, the LAN communication unit I / F unit 140 transmits the transmission data processed by the MAC processing unit 123 to the DU 200, receives the reception data from the DU 200, and outputs the received data to the MAC processing unit 123. Of the LAN communication I / F unit 140, an interface connected to another CU 100 is called, for example, an Xn interface, and an interface connected to the DU 200 is called, for example, an F1 interface. Control information (C plane) transmitted using the Xn interface or F1 interface is transmitted using SCTP (Stream Control Transmission Protocol), and user data (U plane) is transmitted using GTP-U (GPRS Tunneling Protocol for User Plane). ) And UDP (User Datagram Protocol).

FIG. 4 is a block diagram showing a configuration of DU 200 according to the first embodiment. The DU 200 corresponds to the DUs 200a to 200c shown in FIG. 4 includes a LAN communication I / F unit 210, a processor 220, a memory 230, and a wireless transmission / reception unit 240.

The LAN communication I / F unit 210 is connected to the CU 100 and transmits / receives data. Specifically, the LAN communication I / F unit 210 receives transmission data from the CU 100 and transmits the reception data acquired from the PHY processing unit 221 to the CU 100. The LAN communication unit I / F unit 210 can be connected to a plurality of CUs 100, and receives transmission data scheduled by each CU 100.

The processor 220 includes, for example, a CPU, FPGA, DSP, or the like, and performs overall control of the entire DU 200. Specifically, the processor 220 includes a PHY processing unit 221.

The PHY processing unit 221 executes PHY layer processing such as D / A (Digital / Analog) conversion, A / D (Analog / Digital) conversion, and amplification of signals. That is, the PHY processing unit 221 acquires transmission data from the LAN communication I / F unit 210, executes PHY layer processing on the transmission data, and outputs the transmission data to the wireless transmission / reception unit 240. In addition, the PHY processing unit 221 performs PHY layer processing on the reception data output from the wireless transmission / reception unit 240.

The memory 230 includes, for example, a RAM or a ROM, and stores information used by the processor 120 to execute processing.

The wireless transmission / reception unit 240 is a wireless communication unit that wirelessly transmits the transmission data output from the PHY processing unit 221 to the UE 20 via the antenna. In addition, the wireless transmission / reception unit 240 outputs reception data received via the antenna to the PHY processing unit 221.

Next, an operation at the time of setting an interface between the CU 100 and the DU 200 in the wireless communication system configured as described above will be described with reference to a sequence diagram shown in FIG. Hereinafter, a case where the CUs 100a to 100c set an interface with one DU 200 will be described.

First, an interface is set between the CU 100a and the DU 200 (step S101). That is, for example, an F1 interface is set between the LAN communication I / F unit 140 of the CU 100a and the LAN communication I / F unit 210 of the DU 200. Here, since no other CU is connected to the DU 200 and the CU 100a is the CU that first connects to the DU 200, the CU 100a becomes the master. Therefore, the master management unit 125 of the CU 100a stores that the CU 100a is a master.

Note that, here, it is assumed that the CU connected to the DU 200 first becomes the master, but the CU connected to the DU 200 first does not necessarily become the master. For example, a master CU may be determined for each DU 200 in advance, or a CU that is connected to the DU 200 first in a service unit provided by the DU 200 may be a master.

After the F1 interface is set between the CU 100a and the DU 200, the F1 interface is subsequently set between the CU 100b and the DU 200 (step S102). Here, since the CU 100a and the DU 200 are already connected, the DU 200 notifies the CU 100b that the CU 100a is already connected (step S103). This notification includes information that can identify the CU 100a such as an IP (Internet Protocol) address of the CU 100a and a cell ID that uniquely identifies the CU 100a.

Further, since the CU 100a is the master, the DU 200 notifies the CU 100b to that effect (step S104). This notification also includes information that can identify the CU 100a such as the IP address and cell ID of the CU 100a. Upon receiving the notification regarding the master, the master management unit 125 of the CU 100b stores that the CU 100a is the master.

Subsequently, the F1 interface is set between the CU 100c and the DU 200 (step S105). Here, since the

CUs

100a and 100b and the DU 200 are already connected, the DU 200 notifies the CU 100c that the CUs 100a and 100b are already connected (step S106). This notification includes information that can identify the CU 100a and the CU 100b, such as the IP addresses of the

CUs

100a and 100b and the cell IDs corresponding to the

CUs

100a and 100b.

Further, since the CU 100a is the master, the DU 200 notifies the CU 100c to that effect (step S107). This notification includes information that can specify the CU 100a such as the IP address and cell ID of the CU 100a, for example, as described above. In response to the notification regarding the master, the master management unit 125 of the CU 100c stores that the CU 100a is the master.

By such interface setting, a plurality of CUs 100a to 100c connected to the DU 200 share information regarding the master, and the CU 100a is set as the master CU. Thereafter, arbitration of radio resources used by the CUs 100a to 100c for scheduling is executed by the master.

Next, arbitration of radio resources by the master will be described with reference to the sequence diagrams shown in FIGS. FIG. 6 is a sequence diagram illustrating an operation when radio resource arbitration is periodically performed.

The master management unit 125 of the CU 100a that has become the master requests the

slave CUs

100b and 100c to report the amount of radio resources necessary for scheduling in a predetermined cycle (steps S201 and S202). This request may include identification information of the DU 200 in order to specify that the report is related to the DU 200. For example, service identification information may be included to specify that the resource is a radio resource related to a specific service. It may be. In the CU 100a, the master management unit 125 requests the resource control unit 124 to report the same amount of radio resources.

The master management unit 125 of the

slave CUs

100b and 100c that received the request inquires the resource control unit 124 about the amount of radio resources necessary for scheduling and obtains a response. Then, the master management unit 125 of the CUs 100b and 100c transmits the requested resource information including the obtained amount of radio resources to the master CU 100a (steps S203 and S204). The requested resource information includes, for example, the identification information of the target service, the required bandwidth indicated by the number of subcarriers or the number of resource blocks, the maximum transmission data amount in one transmission, the required transmission delay, the buffer retention amount, etc. May be included.

When the requested resource information is received by the CU 100a and the amount of necessary radio resource is reported from the resource control unit 124 of the CU 100a, the master management unit 125 of the CU 100a executes radio resource arbitration (step S205). That is, allocation of the entire radio resources that can be used for scheduling by the CUs 100a to 100c to the CUs 100a to 100c is determined. In this arbitration, allocation is determined so that radio resources used for scheduling by the CUs 100a to 100c do not overlap each other. In addition, due to this arbitration, more radio resources are allocated to CUs in which a shortage of radio resources occurs, and less radio resources are allocated to CUs in which a surplus of radio resources occurs. The In this way, the master management unit 125 controls radio resources.

Then, the master management unit 125 of the CU 100a generates distribution resource information for notifying the distribution of radio resources to the

slave CUs

100b and 100c, and transmits them to the CUs 100b and 100c (steps S206 and S207). Also, information on the radio resources allocated to the CU 100a is notified from the master management unit 125 to the resource control unit 124. The information on the radio resource controlled as described above may be notified as information on the radio resource. Information regarding radio resources for

slave CUs

100b and 100c is notified to

CUs

100b and 100c by network I / F unit 110.

The transmitted allocation resource information is acquired by the master management unit 125 of the CUs 100b and 100c and output to the resource control unit 124. The resource control unit 124 of each of the CUs 100a to 100c specifies, to the MAC processing unit 123, radio resources that the own CU uses for scheduling according to the distributed resource information. Then, the MAC processing unit 123 executes scheduling for assigning the designated radio resource to the radio communication between the DU 200 and the UE 20, and transmission data, for example, is transmitted from each of the CUs 100a to 100c to the DU 200 according to the scheduling result (step) S208 to S210).

By such regular arbitration of radio resources by the master, radio resources used for scheduling by the CUs 100a to 100c do not overlap, and the amount of radio resources used by the respective CUs 100a to 100c is appropriately maintained. However, for example, when a large amount of traffic suddenly occurs in any CU and a large amount of radio resources are required, there is a possibility that a shortage of radio resources may occur only by periodic arbitration. Therefore, it is preferable to temporarily perform radio resource arbitration in addition to periodic radio resource arbitration. FIG. 7 is a sequence diagram illustrating an operation in a case where arbitration of radio resources is temporarily performed.

For example, when a shortage of radio resources occurs in the slave CU 100b, the resource control unit 124 of the CU 100b notifies the master management unit 125 that the shortage of radio resources has occurred and the amount of radio resources necessary for scheduling. Then, the master management unit 125 of the CU 100b transmits request resource information including the notified amount of radio resources to the master CU 100a (step S301).

When the requested resource information is received by the CU 100a, the master management unit 125 of the CU 100a executes radio resource arbitration (step S302). That is, it is determined whether or not to distribute the radio resources allocated to the

other CUs

100a and 100c to the CU 100b that lacks radio resources. As a result of this determination, in the case of allocating radio resources, it is determined how much radio resources allocated to which CU are allocated to the CU 100b. That is, the allocation of new radio resources to compensate for the shortage of radio resources of the CU 100b is determined.

slave CUs

100b and 100c, and transmits the generated resource information to the CUs 100b and 100c (steps S303 and S304). Also, information on the radio resources allocated to the CU 100a is notified from the master management unit 125 to the resource control unit 124. Note that the allocated resource information may not be transmitted to a CU in which the allocated radio resource does not change. That is, for example, when the shortage of radio resources in the CU 100b is allotted from the radio resources allocated to the CU 100a, transmission of allocated resource information to the CU 100c can be omitted.

The transmitted allocation resource information is acquired by the master management unit 125 of the CUs 100b and 100c and output to the resource control unit 124. The resource control unit 124 of each of the CUs 100a to 100c specifies, to the MAC processing unit 123, radio resources that the own CU uses for scheduling according to the distributed resource information. Then, the MAC processing unit 123 executes scheduling for assigning the designated radio resource to the radio communication between the DU 200 and the UE 20, and transmission data, for example, is transmitted from each of the CUs 100a to 100c to the DU 200 according to the scheduling result (step) S305 to S307).

In this way, when a shortage of radio resources occurs, the master performs radio resource arbitration in response to a request from the corresponding CU. Thereby, for example, even when a sudden increase in traffic occurs, it is possible to avoid overlapping allocation of radio resources.

FIG. 8 is a diagram showing an example of changes in the amount of radio resources allocated to the CUs 100a to 100c. In FIG. 8, there is no change in the amount of radio resources allocated to the CUs 100a to 100c at downlink (DL) transmission timings DL # 1 to # 3 at which data is transmitted from the DU 200 to the UE 20. Similarly, the amount of radio resources allocated to the CUs 100a to 100c does not change even in uplink (UL) transmission timings UL # 1 to # 3 at which data is transmitted from the UE 20 to the DU 200. During this time, the CUs 100a to 100c perform scheduling using the allocated radio resources. As a result, the radio resources are not assigned redundantly by the CUs 100a to 100c.

After that, for example, when a shortage of radio resources occurs in the CU 100b, the master CU 100a is requested to add radio resources, and the CU 100a performs radio resource arbitration. Here, for example, radio resources allocated to the CU 100c are allocated to the CU 100b. As a result of this arbitration, the allocation resource information is transmitted from the master to the CUs 100b and 100c, and the radio resources allocated to the CU 100b increase at the downlink transmission timings DL # 4 and DL # 5 and the uplink transmission timing UL # 4. However, the radio resources allocated to the CU 100c are decreasing. As described above, the master CU 100a performs arbitration of radio resources used by the CU 100a to CU 100c for scheduling, so that an appropriate amount of radio resources is allocated to the CUs 100a to 100c. Further, since the radio resources allocated to each of the CUs 100a to 100c do not overlap each other, it is possible to avoid overlapping allocation of radio resources at the time of scheduling.

As described above, according to the present embodiment, each CU shares information related to the master CU at the time of setting the interface between the CU and the DU, and the master CU distributes wirelessly to each CU periodically and temporarily. A resource is determined and distribution resource information is notified to each CU. Since each CU performs scheduling of allocated radio resources according to the allocated resource information, even when a plurality of CUs are connected to one DU, each CU allocates the same radio resource to radio communication. There is no. In other words, it is possible to avoid redundant allocation of radio resources during scheduling.

(Embodiment 2)
The feature of the second embodiment is that the master detects the processing load, and when the processing load is large, the master is changed to another CU.

Since the configuration of the wireless communication system according to Embodiment 2 is the same as that of Embodiment 1 (FIG. 2), description thereof is omitted. FIG. 9 is a block diagram showing a configuration of CU 100 according to the second embodiment. 9, the same parts as those in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted. The CU 100 illustrated in FIG. 9 includes a processing load detection unit 301 and a master management unit 302 instead of the master management unit 125 of the CU 100 illustrated in FIG.

The processing load detection unit 301 detects the processing load in the CU 100. Specifically, when the CU 100 is a master, the processing load detection unit 301 monitors, for example, the operation rate of the processor 120 or the number of DUs 200 that the CU 100 operates as a master as the processing load, and the processing load is predetermined. It is determined whether or not the reference is exceeded. Then, when the processing load is equal to or greater than a predetermined reference, the processing load detection unit 301 notifies the master management unit 302 to that effect. In this manner, the processing load detection unit 301 collects (acquires) information regarding the processing load status and notifies the master management unit 302 of information regarding the processing load.

On the other hand, when the CU 100 is a slave, the processing load detection unit 301 determines, for example, the processing rate of the processor 120 and the number of DUs 200 that the CU 100 operates as a master when the processing load is inquired from the master. Detect as. Then, the processing load detection unit 301 generates a processing load response including information on the detected processing load and outputs the response to the master management unit 302.

The master management unit 302 manages information on the master CU for each DU 200 to which the CU 100 is connected. Then, when the CU 100 is a master, the master management unit 302 requests a slave connected to the same DU 200 to periodically report the amount of necessary radio resources. When the amount of necessary radio resources is reported from the slave, the master management unit 302 determines the allocation of radio resources for each CU including the CU 100 and notifies the determined allocation to each slave. Further, when the processing load detection unit 301 is notified that the processing load is equal to or greater than a predetermined reference, the master management unit 302 inquires of the slave about the processing load. When the processing load response is received from the slave, the master management unit 302 determines a new master based on the processing load of each slave, and transmits information on the new master to each slave.

On the other hand, when the CU 100 is a slave, the master management unit 302 inquires the resource control unit 124 about the amount of radio resources necessary for scheduling in response to a request from the master, and sends a response from the resource control unit 124 to the master. Report to In addition, when the resource control unit 124 reports that a shortage of radio resources has occurred, the master management unit 302 requests the master to increase radio resource allocation. Further, the master management unit 302 transmits the processing load response generated by the processing load detection unit 301 to the master when there is an inquiry about the processing load from the master.

Next, the operation at the time of master change in the wireless communication system configured as described above will be described with reference to the sequence diagram shown in FIG. Below, the case where a master is changed from CU100a to CU100b is demonstrated.

In the master CU 100a, the processing load is monitored by the processing load detector 301. This processing load is, for example, the operating rate of the processor 120 or the number of DUs 200 that the CU 100a operates as a master. When the processing load detection unit 301 detects that the processing load is equal to or greater than a predetermined reference (step S401), the master management unit 302 transmits an inquiry about the processing load to the

slave CUs

100b and 100c ( Steps S402 and S403).

The processing load detection unit 301 detects the processing load in the

slave CUs

100b and 100c for which the processing load has been inquired. That is, for example, the operating rate of the processor 120 and the number of DUs 200 that the CUs 100b and 100c operate as masters are detected as the processing load. Then, a processing load response including information on the detected processing load is transmitted from the master management unit 302 of each of the CUs 100b and 100c (steps S404 and S405).

When the processing load response is received by the CU 100a, the master management unit 302 of the CU 100a determines a new master based on the processing load of the slave (step S406). Specifically, for example, a CU having the smallest processing load and a smaller processing load than the current master CU 100a is determined as a new master. Here, the description will be continued assuming that the CU 100b is determined as a new master.

When a new master is determined, the master management unit 302 of the CU 100a transmits to the CU 100b, which is the new master, charge request information (charge request information) for requesting (requesting) a master charge (step request information). S407). When the master management unit 302 of the CU 100b determines that the master can be in charge of the charge request information, charge approval information for approving the master charge is transmitted to the CU 100a (step S408). If the master management unit 302 of the CU 100b determines that it is not possible to take charge of the master, charge rejection information for rejecting the master charge may be transmitted to the CU 100a.

When the responsible approval information is received by the CU 100a, the master management unit 302 of the CU 100a transmits a master change notification notifying that the master is changed to the CU 100b to the CUs 100b and 100c (steps S409 and S410). As a result, the master for the DU 200 is changed from the CU 100a to the CU 100b, and thereafter, the CU 100b determines the allocation of radio resources to the CUs 100a to 100c.

As described above, according to the present embodiment, when the processing load of the master CU increases, the master inquires about the processing load of the slave CU and requests the slave in charge of the master to handle the master. When the request is approved, the master is changed, so that the CU with a small processing load operates as the master, and the control delay related to the arbitration of radio resources can be reduced. As a result, arbitration of radio resources is performed quickly, and scheduling and data transmission delays by each CU can be suppressed.

Note that the master change described in the second embodiment may be performed individually for each DU 200. That is, since the master is determined for each DU 200, for example, when the CU 100a is a master for two different DUs 200, the master for only one DU 200 can be changed.

Specifically, for example, as shown in FIG. 11, when it is detected that the processing load of the CU 100a is large when the CU 100a is a master for DU # 1 and DU # 2 (step S401), the master change described above is performed. Is performed (steps S402 to S410). However, here, it is assumed that the master for only DU # 1 of DU # 1 and DU # 2 is changed to CU100b, and CU100a continues to be DU # 2 even after CU100b becomes the master for DU # 1. Master about.

In this way, it is possible to change the master individually for each DU 200, and the processing load of the master CU can be distributed in a flexible manner.

110 Network I / F unit 120, 220 Processor 121 PDCP processing unit 122 RLC processing unit 123 MAC processing unit 124 Resource control unit 125, 302 Master management unit 130, 230

Memory

140, 210 LAN communication I / F unit 221 PHY processing unit 240 Wireless transceiver 301 Processing load detector

Claims

A wireless communication system having a first wireless control device, a second wireless control device, a wireless device, and a wireless terminal device,
The first radio control device is:
A transmission unit for notifying the second wireless control device of a request related to the first wireless resource for communication according to the control of the first wireless control device;
The second radio control device is:
A receiving unit for receiving a request regarding the first radio resource notified from the first radio control device;
A management unit that controls the first radio resource and a second radio resource used for radio communication by the radio device connected to the second radio control device;
A notification unit for notifying the first radio control device of information related to the first radio resource controlled by the management unit;
A scheduling unit that allocates a third radio resource that is at least a part of the second radio resource controlled by the management unit for communication between the second radio control device and the radio terminal device; ,
The wireless device includes:
A wireless communication system comprising: a wireless communication unit that wirelessly communicates with the wireless device using the third wireless resource.
The transmitter is
The wireless communication system according to claim 1, wherein a request for the first wireless resource is notified to the second wireless control device at a predetermined cycle.
The transmitter is
The radio communication system according to claim 1, wherein when the first radio resource varies, a request for radio resources is notified to the second radio control apparatus.
The second radio control device is:
A processing load detector that acquires information about the processing load of the first wireless control device and notifies the management unit;
The notification unit
The control unit according to claim 1, wherein the first radio control device is requested to control radio resources used by a third radio control device different from the first and second radio control devices. Wireless communication system.
A scheduling unit for performing scheduling for allocating radio resources for radio communication by a radio device;
A receiving unit for receiving a request regarding radio resources used in scheduling of the own device and / or another radio control device;
A management unit that controls radio resources used by the other radio control device;
A radio control apparatus comprising: a notification unit configured to notify the other radio control apparatus of information related to radio resources controlled by the management unit.
In a radio communication system having a radio device, a first radio control device, a second radio control device, and a radio terminal device, a radio resource control method executed by the first radio control device,
Receiving a request from the second radio control apparatus regarding a second radio resource for communicating according to the control of the second radio control apparatus;
Controlling the second radio resource and the first radio resource used by the radio device connected to the first radio control device for radio communication;
A radio resource control method comprising: a process of notifying the second radio control apparatus of information related to the controlled second radio resource.