WO2019187163A1

WO2019187163A1 - Communication control device, wireless device, and wireless communication system

Info

Publication number: WO2019187163A1
Application number: PCT/JP2018/014011
Authority: WO
Inventors: 喬裕向田; 彰島元; 大出　高義
Original assignee: 富士通株式会社
Priority date: 2018-03-30
Filing date: 2018-03-30
Publication date: 2019-10-03

Abstract

This communication control device (20) includes a wireless communication control unit (2116), a communication unit (210), and a selection unit (2114). The wireless communication control unit controls a communication with a terminal device that uses a first wireless frequency, or controls a communication with the terminal device through a connected wireless device. The communication unit transmits, to other communication control devices, a signal for requesting control information relating to whether a communication is possible with the terminal device by using a second wireless frequency that is different from the first wireless frequency. In addition, the communication unit receives signals including the control information from the other communication control devices. The selection unit selects, from among the other communication control devices, one communication control device that uses the second wireless frequency and performs the communication with the terminal device. In addition, the communication unit transmits, to the one communication control device, a control signal including information relating to the communication with the terminal device that uses the second wireless frequency.

Description

COMMUNICATION CONTROL DEVICE, RADIO DEVICE, AND RADIO COMMUNICATION SYSTEM

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

In the current network, traffic from mobile terminals (smartphones and feature phones) occupies most of the network resources. In addition, the traffic used by mobile terminals tends to continue to expand.

On the other hand, in response to the development of IoT (Internet of a things) services (for example, monitoring systems for traffic systems, smart meters, devices, etc.), it is required to support services with various requirements. Therefore, in addition to the standard technology of 4G (4th generation mobile communication) (for example, Non-Patent Documents 1 to 11), the communication standard of 5th generation mobile communication (5G or NR (New Radio)) further There is a need for a technology that achieves a high data rate, large capacity, and low delay. Regarding the 5th generation communication standard, technical studies are underway by 3GPP working groups (for example, TSG-RAN WG1, TSG-RAN WG2, etc.). (For example, non-patent documents 12 to 39)

As described above, in order to support a wide variety of services, 5G is classified into eMBB (Enhanced Mobile BroadBand), Massive MTC (Machine Type Communications), and URLLC (Ultra-Reliable and Low Latency Communications). Support for many use cases is envisioned.

In addition, as one of the solutions for increasing the capacity of wireless networks due to the recent increase in traffic, HetNet (Heterogenious Network) is being studied to offload macrocell wireless traffic to small cells with relatively low transmission power. I have been. By applying CA (Carrier Aggregation) and DC (Dual Connectivity) technologies to HetNet, it is possible to realize not only the stability of communication but also the capacity expansion by small cells. DC is a technique for offloading communication traffic to adjacent base stations.

By the way, if communication traffic increases, base stations such as macro cells and small cells may become congested. For example, when an adjacent base station is in a congested state, the DC is rejected even if the base station requests DC from the adjacent base station. Therefore, the base station requests DC from a plurality of neighboring base stations in order to find a neighboring base station that accepts the DC. As a result, it takes time until the DC is established, and it is difficult to increase the transmission speed.

In recent wireless communication systems, a high-density cell arrangement such as a pico cell is adopted. Furthermore, in 5G, use of a wireless device having a narrower cover range than in the past, such as millimeter waves, is being studied, and it is assumed that the density of base stations will further increase. For this reason, the number of neighboring base stations that are candidates for DC requests also increases, and the time required to find a macro cell that accepts a DC tends to increase.

The disclosed technology has been made in view of the above, and an object thereof is to provide a communication control device, a wireless device, and a wireless communication system that can establish DC more quickly.

The communication control device disclosed in the present application includes, in one aspect, a wireless communication control unit, a transmission unit, a reception unit, and a selection unit. The wireless communication control unit controls communication with the terminal device using the first radio frequency, or controls communication with the terminal device via the connected wireless device. A transmission part transmits the signal which requests | requires the control information regarding the communication availability with a terminal device using the 2nd radio frequency different from a 1st radio frequency with respect to another communication control apparatus. The receiving unit receives a signal including control information from another communication control device. The selection unit selects one communication control device that communicates with the terminal device using the second radio frequency from another communication control device. In addition, the transmission unit transmits a control signal including information related to communication with the terminal device using the second radio frequency to one communication control device.

According to one aspect of the communication control device, the wireless device, and the wireless communication system disclosed in the present application, it is possible to establish DC more quickly.

FIG. 1 is a diagram illustrating an example of a wireless communication system according to the first embodiment. FIG. 2 is a block diagram illustrating an example of a base station that functions as a master base station in the first embodiment. FIG. 3 is a diagram illustrating an example of base station information according to the first embodiment. FIG. 4 is a block diagram illustrating an example of a base station that functions as a secondary base station in the first embodiment. FIG. 5 is a block diagram illustrating an example of a terminal device. FIG. 6 is a diagram illustrating an example of data included in an MR (Measurement Report). FIG. 7 is a diagram illustrating an example of processing of the wireless communication system according to the first embodiment. FIG. 8 is a block diagram illustrating an example of a base station that functions as a master base station in the second embodiment. FIG. 9 is a block diagram illustrating an example of a base station that functions as a secondary base station in the second embodiment. FIG. 10 is a diagram illustrating an example of processing of the wireless communication system according to the second embodiment. FIG. 11 is a block diagram illustrating an example of a base station that functions as a master base station in the third embodiment. FIG. 12 is a diagram illustrating an example of processing of the wireless communication system according to the third embodiment. FIG. 13 is a diagram illustrating an example of a wireless communication system according to the fourth embodiment. FIG. 14 is a block diagram illustrating an example of a base station that functions as a master base station in the fourth embodiment. FIG. 15 is a diagram illustrating an example of base station information according to the fourth embodiment. FIG. 16 is a block diagram illustrating an example of a base station that functions as a secondary base station in the fourth embodiment. FIG. 17 is a diagram illustrating an example of data included in the resource information in the fourth embodiment. FIG. 18 is a diagram illustrating an example of processing of the wireless communication system according to the fourth embodiment. FIG. 19 is a diagram illustrating an example of a wireless communication system according to the fifth embodiment. FIG. 20 is a block diagram illustrating an example of a CU-CP according to the fifth embodiment. FIG. 21 is a diagram illustrating an example of base station information according to the fifth embodiment. FIG. 22 is a diagram illustrating an example of data included in resource information in the fifth embodiment. FIG. 23 is a block diagram illustrating an example of a CU-UP according to the fifth embodiment. FIG. 24 is a diagram illustrating an example of processing of the wireless communication system according to the fifth embodiment. FIG. 25 is a block diagram illustrating an example of a CU-CP according to the sixth embodiment. FIG. 26 is a diagram illustrating an example of processing of the wireless communication system according to the sixth embodiment.

Hereinafter, embodiments of a communication control device, a wireless device, and a wireless communication system disclosed in the present application will be described in detail with reference to the drawings. The disclosed technology is not limited by the following embodiments. In addition, the embodiments can be appropriately combined within a range in which processing contents are not contradictory.

[Wireless communication system 10]
FIG. 1 is a diagram illustrating an example of a wireless communication system 10 according to the first embodiment. The wireless communication system 10 includes a plurality of base stations 20 (20-1, 20-2,...) And a terminal device 30. In the example of FIG. 1, the base station 20-1 forms a cell 200-1, and the base station 20-2 forms a cell 200-2. In the following description, a plurality of base stations 20-1, 20-2,... .. Are collectively referred to as the cell 200 without being distinguished from each other. Each base station 20 is connected to the core network 11, controls the wireless connection of the terminal device 30, and relays communication between the terminal device 30 and the core network 11. Each base station 20 is an example of a communication control device.

The terminal device 30 can perform wireless communication by DC (Dual Connectivity) between the two base stations 20. DC refers to wireless communication performed using the first radio frequency with one of the two base stations 20 and the first radio frequency with the other base station 20. This is wireless communication in which wireless communication performed using different wireless frequencies is performed simultaneously. Hereinafter, one of the two base stations 20 that performs DC with the terminal device 30 is described as a base station 20m that functions as a main base station in DC, and the other is a base station 20s that functions as a secondary base station in DC. It describes.

[Base station 20m]
FIG. 2 is a block diagram illustrating an example of the base station 20m that functions as a master base station in the first embodiment. For example, as illustrated in FIG. 2, the base station 20 m includes a communication unit 210, a control unit 211, a memory 212, a radio unit 213, and an antenna 214. The base station 20m has a control device such as a BBU (Base Band Unit) and a radio device such as an RRH (Remote Radio Head), and the communication unit 210, the control unit 211, and the memory 212 are provided in the BBU. The radio unit 213 may be provided in the RRH.

The communication unit 210 is realized by, for example, a NIC (Network Interface Card) or the like, and transmits and receives signals to and from the core network 11. The communication unit 210 is an example of a transmission unit, a reception unit, and a transmission / reception unit. In the memory 212, for example, base station information 2120 is stored. In the memory 212, various programs executed by the control unit 211 are stored. The control unit 211 includes a processor such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor), for example, and implements each function of the control unit 211 by executing a program read from the memory 212.

The radio unit 213 transmits a radio signal via the antenna 214 to form the cell 200 in a range where the radio signal reaches. Further, the radio unit 213 performs, for example, physical layer processing on the signal output from the control unit 211 and the signal received via the antenna 214. For example, the wireless unit 213 converts the signal output from the control unit 211 from a digital signal to an analog signal. The radio unit 213 performs processing such as up-conversion, amplification, and filtering on the converted signal, and radiates the processed signal to the space via the antenna 214. The radio unit 213 performs processing such as filtering, amplification, and down-conversion on the signal received via the antenna 214. The wireless unit 213 converts the processed signal from an analog signal to a digital signal and outputs the converted signal to the control unit 211.

Note that not all the programs and data in the memory 212 are necessarily stored in the memory 212 from the beginning. For example, a program or data is stored in a portable recording medium such as a memory card inserted into the base station 20m, and the base station 20m appropriately acquires and executes the program or data from such a portable recording medium. It may be. Further, the base station 20m appropriately acquires and executes the program etc. from another computer or server device storing the program, data, etc. via a wireless communication line, public line, Internet, LAN, WAN, etc. It may be.

In the memory 212, for example, base station information 2120 as shown in FIG. 3 is stored. FIG. 3 is a diagram illustrating an example of the base station information 2120. In the base station information 2120, for example, a base station ID and access information are stored in association with a cell ID for identifying each cell 200. The base station ID is information for identifying each base station 20. The access information is information for accessing the base station 20 identified by the corresponding base station ID, such as address information. The base station information 2120 is stored in the memory 212 in advance by an administrator of the base station 20 or the like.

The control unit 211 executes a program read from the memory 212, thereby executing a DC execution determination unit 2110, a request unit 2111, a collection unit 2112, a DC availability determination unit 2113, a selection unit 2114, a DC processing unit 2115, and wireless communication control. Each function of the unit 2116 is realized.

The DC execution determination unit 2110 determines whether or not communication with the terminal device 30 is executed by DC. The DC execution determination unit 2110 determines whether or not to perform communication with the terminal device 30 by DC based on, for example, the state of the resource of the base station 20m. The resource state includes, for example, the free capacity of the buffer and the capacity of the interface with the core network 11. In addition, the resource state may include the traffic volume of communication performed with the terminal device 30, the usage rate of the processor, the usage rate of the memory 212, or the like.

The DC execution determination unit 2110 creates an MR request for requesting MR (Measurement Report) to the terminal device 30 when it is determined that communication with the terminal device 30 is executed by DC. Then, the DC execution determining unit 2110 transmits the created MR request to the terminal device 30 via the wireless unit 213. The terminal device 30 that has received the MR request measures the quality of the signal transmitted from the base station 20 in the surrounding cell 200. And the terminal device 30 transmits MR containing the quality information which shows the quality of the signal for every surrounding cell 200 to the base station 20m.

When the request unit 2111 receives an MR from the terminal device 30 via the radio unit 213, the request unit 2111 requests resource information including information indicating the state of the resource based on the quality information for each cell 200 included in the MR. One or more other base stations 20 to which the request is transmitted are specified. Then, the request unit 2111 transmits a resource information request to the other identified base station 20 via the communication unit 210 and the core network 11. The resource information request is transmitted by multicast, for example.

The request unit 2111 identifies, for example, another base station 20 that manages each of the cells 200 as the base station 20 that is the transmission destination of the resource information request for a predetermined number of cells 200 in order of good signal quality. In addition, for example, for the cell 200 in which the signal quality is better than the predetermined quality, the request unit 2111 specifies another base station 20 that manages each cell 200 as the base station 20 that is the transmission destination of the resource information request. Also good.

The other base station 20 that has received the resource information request from the request unit 2111 collects information indicating the state of the resource of the own device, and sends the resource information including the collected information to the base station 20m via the core network 11. Send. The resource information is the state of the resource that the base station 20 has, and is, for example, the free capacity of the buffer and the capacity of the interface with the core network 11. In addition, the resource information may include a processor usage rate or a memory usage rate. Further, the resource information may be radio resource information.

The collection unit 2112 collects resource information transmitted from other base stations 20 via the communication unit 210 and the core network 11.

The DC availability determination unit 2113 determines whether or not DC is possible for each of the other base stations 20 based on the resource information collected by the collection unit 2112. Then, the DC availability determination unit 2113 outputs DC information indicating the determination result to the selection unit 2114.

The selection unit 2114 acquires DC information from the DC availability determination unit 2113 for each of the other base stations 20 before DC is requested of the other base station 20. Based on the DC information of each of the other base stations 20 output from the DC availability determination unit 2113, the selection unit 2114 includes the other base stations 20 corresponding to the DC information indicating that DC is possible. The other base station 20 that requests DC is selected. For example, the selection unit 2114 requests other base stations 20 that manage the cell 200 with good signal quality from other base stations 20 corresponding to DC information indicating that DC is possible. The base station 20 is preferentially selected. Then, the selection unit 2114 outputs information on the selected other base station 20 to the DC processing unit 2115.

The DC processing unit 2115 transmits a DC request, which is a control signal for requesting DC, to the other base station 20 selected by the selection unit 2114 via the communication unit 210 and the core network 11. Then, the DC processing unit 2115 performs wireless communication with the terminal device 30 through DC in cooperation with the other base station 20 selected by the selection unit 2114. The DC processing unit 2115 is an example of a control unit.

The wireless communication control unit 2116 controls a protocol for wireless communication with the terminal device 30 via the wireless unit 213. The radio communication control unit 2116 executes, for example, RRC layer, PDCP layer, RLC layer, and MAC layer processing. RRC is an abbreviation for Radio Resource Control, PDCP is an abbreviation for Packet Data Convergence Protocol, RLC is an abbreviation for Radio Link Control, and MAC is an abbreviation for Media Access Control.

[Base station 20s]
FIG. 4 is a block diagram illustrating an example of a base station 20s that functions as a secondary base station in the first embodiment. For example, as illustrated in FIG. 4, the base station 20 s includes a communication unit 210, a control unit 211, a memory 212, a radio unit 213, and an antenna 214. In FIG. 4, blocks with the same reference numerals as those in FIG. 2 are the same as the blocks described in FIG.

The DC processing unit 2115 performs wireless communication with the terminal device 30 by DC in cooperation with the base station 20m. The resource management unit 2117 manages the state of resources in the base station 20s. When the resource management unit 2117 receives a resource information request from the base station 20 m via the core network 11 and the communication unit 210, the resource management unit 2117 transmits the resource information of the base station 20 s to the base station via the communication unit 210 and the core network 11. Send to 20m.

In this embodiment, the base station 20m that functions as a master base station and the base station 20s that functions as a secondary base station are described as separate devices, but the base station 20m and the base station 20s are the same. The base station 20 may be configured. The same applies to the second and subsequent embodiments.

[Terminal device 30]
FIG. 5 is a block diagram illustrating an example of the terminal device 30. For example, as illustrated in FIG. 5, the terminal device 30 includes an antenna 31, a radio unit 32, a control unit 33, and a memory 34.

The radio unit 32 executes, for example, physical layer processing on the signal received from the base station 20 via the antenna 31 and the signal output from the control unit 33. For example, the radio unit 32 performs processing such as filtering, amplification, and down-conversion on a signal received from the base station 20 via the antenna 31. The wireless unit 32 converts the processed signal from an analog signal to a digital signal and outputs the converted signal to the control unit 33. The radio unit 32 converts the signal output from the control unit 33 from a digital signal to an analog signal. Then, the radio unit 32 performs processes such as up-conversion, amplification, and filtering on the converted signal, and transmits the processed transmission signal to the base station 20 via the antenna 31.

In the memory 34, various programs and data executed by the control unit 33 are stored. The control unit 33 has a processor such as a CPU or a DSP, for example, and implements each function of the control unit 33 by executing a program read from the memory 34.

Note that not all programs, data, and the like in the memory 34 need be stored in the memory 34 from the beginning. For example, a program, data, or the like is stored in a portable recording medium such as a memory card inserted into the terminal device 30, and the terminal device 30 appropriately acquires the program, data, etc. from such a portable recording medium and executes it. It may be. In addition, the terminal device 30 appropriately acquires and executes the program or the like from another computer or server device that stores the program or data through a wireless communication line, a public line, the Internet, a LAN, a WAN, or the like. It may be.

The control unit 33 implements the functions of the measurement unit 330, the MR processing unit 331, the DC processing unit 332, and the wireless communication control unit 333 by executing the program read from the memory 34.

The measuring unit 330 measures the quality of the signal transmitted from the base station 20 in the surrounding cell 200.

When the MR processing unit 331 receives an MR request from the base station 20 via the wireless unit 32, the MR processing unit 331 acquires quality information indicating the signal quality for each cell 200 from the measurement unit 330. Then, the MR processing unit 331 creates an MR including quality information for each cell 200 and transmits the created MR to the base station 20 via the radio unit 32.

FIG. 6 is a diagram illustrating an example of data included in the MR 40. In the MR 40, for example, as illustrated in FIG. 6, the quality information of the signal transmitted from the base station 20 in each cell 200 is associated with a cell ID that identifies the cell 200. The signal quality information is, for example, RSRP (Reference Signal Received Power), RSSI (Received Signal Strength Indicator), or RSRQ (Reference Signal Received Quality). The signal quality information is an example of radio channel quality.

The DC processing unit 332 performs wireless communication by DC between the base station 20m and the base station 20s. The wireless communication control unit 333 controls a protocol for wireless communication with the base station 20 via the wireless unit 32. For example, the radio communication control unit 333 performs processing of the RRC layer, the PDCP layer, the RLC layer, and the MAC layer.

[Processing of Radio Communication System 10]
FIG. 7 is a diagram illustrating an example of processing of the wireless communication system 10 according to the first embodiment. In the example of FIG. 7, a radio communication system 10 including one terminal device 30, one base station 20m functioning as a master base station, and n base stations 20s functioning as secondary base station candidates is assumed. Has been.

First, the base station 20m functioning as a master base station determines whether or not to communicate with the terminal device 30 by DC based on the resource status of the base station 20m, and the DC communicates with the terminal device 30. It is determined to execute communication (S100). Then, the base station 20m transmits an MR request to the terminal device 30 using a radio signal (S101).

When the terminal device 30 receives the MR request, the terminal device 30 measures the quality of the signal transmitted from the base station 20 in the surrounding cell 200. And the terminal device 30 produces MR containing the quality information which shows the quality of the signal for every surrounding cell 200, and transmits produced MR to the base station 20m (S102).

When the base station 20m receives the MR from the terminal device 30, the base station 20m specifies one or more base stations 20s as the transmission destination of the resource information request based on the quality information for each cell 200 included in the MR (S103). Then, the base station 20m transmits a resource information request to the identified base station 20s via the core network 11 (S104). The resource information request is transmitted by multicast, for example.

When each base station 20s receives a resource information request from the base station 20m via the core network 11, the base station 20s transmits the resource information of the base station 20s to the base station 20m via the core network 11 (S105-1 to S105-1). 105-n).

The base station 20m collects resource information transmitted from the base station 20s via the core network 11. Then, the base station 20m determines whether DC is possible for each base station 20s based on the collected resource information (S106).

Then, the base station 20m selects a base station 20s that is a transmission destination of a DC request, which is a control signal for requesting DC, from the base stations 20s capable of DC (S107). The base station 20m selects, for example, the base station 20s that manages the cell 200 having the best signal quality as the base station 20s that requests DC from among the base stations 20s that can perform DC. In the example of FIG. 7, the base station 20s-1 is the base station 20s having the best signal quality among the base stations 20s capable of DC.

Then, the base station 20m transmits the DC request to the base station 20s (for example, the base station 20s-1) selected in step S107 via the core network 11 (S108). The base station 20s-1 that has received the DC request transmits an ACK (ACKnowledgement) indicating acceptance of the DC request to the base station 20m via the core network 11. Then, the base station 20m and the base station 20s-1 cooperate to execute wireless communication with the terminal device 30 by DC.

[Effect of Example 1]
In the above, Example 1 was demonstrated. As described above, the base station 20m of this embodiment includes the selection unit 2114 and the DC processing unit 2115. The selection unit 2114 obtains DC information indicating whether or not DC is possible for each of the plurality of base stations 20s before requesting the DC to the base station 20s. Then, the selection unit 2114 selects the base station 20s that requests DC from the base stations 20s corresponding to DC information indicating that DC is possible. The DC processing unit 2115 transmits a control signal requesting DC to the base station 20s selected by the selection unit 2114.

Here, if the base station 20m transmits a DC request to the base station 20s regardless of whether or not DC is possible, the DC request may be rejected depending on the resource state of the base station 20s. is there. When the DC request is rejected, the base station 20m transmits the DC request to the other base station 20s in order to find the base station 20s that accepts the DC. If the rejection of the DC request is repeated, it takes time until the DC is established, and it is difficult to increase the transmission speed of wireless communication with the terminal device 30.

On the other hand, before transmitting the DC request to the other base stations 20, the base station 20 of the present embodiment identifies the other base stations 20 capable of DC for each of the other base stations 20. Then, the base station 20 selects another base station 20 that requests DC from among the other base stations 20 capable of DC. Thereby, the base station 20 of a present Example can raise possibility that a DC request | requirement will be accepted, and can establish DC more rapidly.

In the base station 20 of the first embodiment described above, the selection unit 2114 receives the data transmitted by the DC among the other base stations 20 corresponding to the DC information indicating that the DC is possible. The other base station 20 that manages a cell with a good signal quality measured by the device 30 is preferentially selected as another base station 20 that requests DC. Thereby, the base station 20 of a present Example can provide the radio | wireless communication by DC more stably in cooperation with the other base station 20. FIG.

In addition, the base station 20 in the first embodiment includes the collection unit 2112 and the DC availability determination unit 2113. The collection unit 2112 collects resource information indicating the state of the resources of the other base stations 20 from each of the other base stations 20. The DC availability determination unit 2113 determines whether or not DC is possible for each of the other base stations 20 based on the resource information, and outputs DC information indicating the determination result to the selection unit 2114. Thereby, the selection unit 2114 can acquire DC information indicating whether or not DC is possible for each of the plurality of base stations 20s.

In addition, the base station 20 in the first embodiment described above includes a request unit 2111. For example, the request unit 2111 requests resource information from other base stations 20 that manage each cell 200 for a predetermined number of cells 200 in order of good signal quality measured by the terminal device 30. Thereby, the base station 20 of the present embodiment can provide more stable wireless communication by DC in cooperation with other base stations 20, and can suppress communication traffic due to transmission of resource information. .

In the first embodiment described above, the request unit 2111 transmits, for example, a cell 200 whose signal quality measured by the terminal device 30 is better than a predetermined quality to other base stations 20 that manage each cell 200. Resource information may be requested. Thereby, the base station 20 of the present embodiment can provide more stable wireless communication by DC in cooperation with other base stations 20, and can suppress communication traffic due to transmission of resource information. .

In Example 1, the base station 20m that functions as a master base station determines whether or not DC is possible for each base station 20s based on the resource information collected from the base station 20s that functions as a candidate for a secondary base station. On the other hand, in the second embodiment, each base station 20s determines whether or not DC is possible, and the base station 20m selects the base station 20s that requests DC based on the determination result by each base station 20s. This is different from the first embodiment. The configuration of the wireless communication system 10 is the same as that of the wireless communication system 10 according to the first embodiment described with reference to FIG.

[Base station 20m]
FIG. 8 is a block diagram illustrating an example of a base station 20m that functions as a master base station in the second embodiment. Except for the points described below, in FIG. 8, blocks denoted by the same reference numerals as those in FIG. 2 have the same or similar functions as the blocks in FIG. The control unit 211 of the base station 20m in the second embodiment executes a program read from the memory 212, thereby executing a DC execution determination unit 2110, a request unit 2111, a selection unit 2114, a DC processing unit 2115, and a wireless communication control unit. Each function of 2116 is realized.

When the request unit 2111 receives an MR from the terminal device 30 via the radio unit 213, the request unit 2111 requests another base station that determines whether or not DC is possible based on the quality information for each cell 200 included in the MR. One or more 20 are specified.

Then, the request unit 2111 transmits a DC determination request for requesting determination of whether or not DC is possible, to the identified base station 20 via the communication unit 210 and the core network 11. The DC determination request includes information related to communication traffic shared with the base station 20m by DC. The DC determination request is transmitted by multicast, for example.

The selection unit 2114 acquires DC information indicating whether or not DC is possible from each of the other base stations 20. The DC information is acquired from each other base station 20 before DC is requested to the other base station 20. Then, the selection unit 2114 requests DC from the other base stations 20 corresponding to the DC information indicating that DC is possible based on the acquired DC information of each other base station 20. Another base station 20 is selected.

[Base station 20s]
FIG. 9 is a block diagram illustrating an example of a base station 20s that functions as a secondary base station in the second embodiment. Except for the points described below, in FIG. 9, blocks denoted by the same reference numerals as those in FIG. 4 have the same or similar functions as the blocks in FIG. The control unit 211 of the base station 20 s in the second embodiment executes each program of the DC availability determination unit 2113, the DC processing unit 2115, the wireless communication control unit 2116, and the resource management unit 2117 by executing the program read from the memory 212. Realize the function.

When receiving a DC determination request from the base station 20m, the DC availability determination unit 2113 determines whether or not DC is possible based on the state of the resource in the own device. Then, the DC availability determination unit 2113 transmits DC information indicating the determination result to the base station 20m via the communication unit 210 and the core network 11. The DC information may include information indicating availability of each resource in addition to information indicating whether or not DC is possible. As a result, the base station 20m that has received the DC information can preferentially select the base station 20 with sufficient resources among other base stations 20 capable of DC.

[Processing of Radio Communication System 10]
FIG. 10 is a diagram illustrating an example of processing of the wireless communication system 10 according to the second embodiment. Except for the points described below, in FIG. 10, the processes denoted by the same reference numerals as those in FIG. 7 are the same as the processes described in FIG.

When the MR is received from the terminal device 30, the base station 20m specifies one or more base stations 20s that are transmission destinations of the DC determination request based on the quality information for each cell 200 included in the MR (S110). Then, the base station 20m transmits a DC determination request to the identified base station 20s via the core network 11 (S111). The DC determination request is transmitted by multicast, for example.

Each base station 20s that has received the DC determination request determines whether or not DC is possible based on the state of the resource in the own device (S112-1 to 112-n). Then, each base station 20s transmits DC information indicating the determination result to the base station 20m via the core network 11 (S113-1 to 113-n). And the process after step S107 is performed.

[Effect of Example 2]
The example 2 has been described above. As described above, in the present embodiment, the request unit 2111 transmits a DC determination request for requesting determination of whether or not DC is possible to each of the other base stations 20. Then, the selection unit 2114 acquires DC information from the other base station 20. Thereby, the process of determining whether or not DC is possible can be distributed to each of the other base stations 20.

Further, in the second embodiment, the DC determination request may include information regarding communication traffic assigned to another base station 20 in the DC. Thereby, the other base station 20 which received DC determination request | requirement can perform the determination whether DC is possible more accurately.

In the first embodiment, when execution of DC is determined, the base station 20m functioning as a master base station collects resource information from other base stations 20, and requests DC based on the collected resource information. Other base stations 20 to be determined have been determined. On the other hand, in the third embodiment, each base station 20 collects resource information from other base stations 20 before the execution of DC is decided, and is collected when the execution of DC is decided. Based on the resource information, another base station 20 that requests DC is determined. The configuration of the wireless communication system 10 is the same as that of the wireless communication system 10 according to the first embodiment described with reference to FIG.

[Base station 20m]
FIG. 11 is a block diagram illustrating an example of a base station 20m that functions as a master base station in the third embodiment. Except for the points described below, in FIG. 11, blocks denoted by the same reference numerals as those in FIG. 2 have the same or similar functions as the blocks in FIG.

In the memory 212 of the base station 20m in the third embodiment, base station information 2120 and resource information 2121 are stored. Resource information 2121 stores resource information collected from other base stations 20 in association with cell IDs.

The control unit 211 executes each of the DC execution determination unit 2110, the collection unit 2112, the DC availability determination unit 2113, the selection unit 2114, the DC processing unit 2115, and the wireless communication control unit 2116 by executing the program read from the memory 212. Realize the function.

The collection unit 2112 receives the resource information transmitted from the other base station 20 via the communication unit 210 and the core network 11 before the DC execution determination unit 2110 determines to perform communication with the terminal device 30 by DC. To collect. Then, the collection unit 2112 stores the collected resource information in the resource information 2121 in the memory 212.

The DC availability determination unit 2113 refers to the resource information of the other base station 20 stored in the resource information 2121 when the DC execution determination unit 2110 determines that communication with the terminal device 30 is to be executed by DC. Then, the DC availability determination unit 2113 determines whether or not DC is possible for each of the other base stations 20 based on the resource information stored in the resource information 2121. When the DC execution determination unit 2110 determines that the DC execution determination unit 2110 performs communication with the terminal device 30 by DC, for example, the DC availability determination unit 2113 uses the latest resource information of each other base station 20 stored in the resource information 2121, for example. Based on this, it is determined whether or not DC is possible. Then, the DC availability determination unit 2113 outputs DC information indicating the determination result to the selection unit 2114.

[Base station 20s]
The configuration of the base station 20s in the present embodiment is the same as that in FIG. Therefore, the following description will be given with reference to FIG. Except for the points described below, the blocks described using FIG. 4 are the same as those of the base station 20s according to the first embodiment, and thus detailed description thereof is omitted.

The resource management unit 2117 transmits resource information to the base station 20m via the communication unit 210 and the core network 11 at every predetermined timing. The predetermined timing is, for example, a timing at which each other base station 20 changes the resource state of the other base station 20 by a predetermined amount or more. Thereby, the communication traffic in the collection of resource information can be reduced. The predetermined timing may be a periodic timing.

[Processing of Radio Communication System 10]
FIG. 12 is a diagram illustrating an example of processing of the wireless communication system 10 according to the third embodiment. Except for the points described below, in FIG. 12, the processes denoted by the same reference numerals as those in FIG. 7 are the same as the processes described in FIG.

When each base station 20s detects that the state of the resource has changed by a predetermined amount or more (S120-1 to 120-n), the base station 20s transmits the resource information to the base station 20m via the core network 11 (S121- 1-120-n).

When the base station 20m determines to execute communication with the terminal device 30 by DC (S100), the base station 20m transmits an MR request to the terminal device 30 by a radio signal (S101). The terminal device 30 measures the quality of the signal transmitted from the base station 20 in the surrounding cell 200, and transmits the MR including the quality information for each surrounding cell 200 to the base station 20m (S102).

Next, the base station 20m determines whether or not DC is possible for each base station 20s based on the latest resource information collected from each base station 20s (S106). And the process after step S107 is performed. In addition, the process of step S106 may be performed before the process of step S101, and may be performed in parallel with the process of step S101.

[Effect of Example 3]
The example 3 has been described above. As described above, in this embodiment, the DC execution determination unit 2110 determines whether or not communication with the terminal device 30 is executed by DC. The collection unit 2112 collects the resource information of the other base stations 20 from each of the other base stations 20 before the DC execution determination unit 2110 determines that communication with the terminal device 30 is to be performed by DC. When the DC execution determination unit 2110 determines that the DC execution determination unit 2110 performs communication with the terminal device 30 by DC, the DC availability determination unit 2113 is based on the latest resource information of each other base station 20 collected by the collection unit 2112. Then, it is determined whether or not DC is possible. Thereby, the DC availability determination unit 2113 can determine whether or not DC is possible for each of the other base stations 20 more quickly.

In the above-described third embodiment, the collection unit 2112 collects resource information in each of the other base stations 20 when the resource state of the other base station 20 changes by a predetermined amount or more. Thereby, the communication traffic in the collection of resource information can be reduced.

In the above-described Examples 1 to 3, the base station 20 is realized by a single device. In contrast, in this embodiment, each base station 20 is realized by a plurality of devices including at least one CU (Central Unit) and one DU (Distributed Unit). Is different.

[Wireless communication system 10]
FIG. 13 is a diagram illustrating an example of the wireless communication system 10 according to the fourth embodiment. The wireless communication system 10 includes a plurality of base stations 20 and a terminal device 30. Each base station 20 is connected to the core network 11, controls the wireless connection of the terminal device 30, and relays communication between the terminal device 30 and the core network 11.

The base station 20-1 has a CU 22-1 and a plurality of DUs 23-1 to 23-3, and the base station 20-2 has a CU 22-2 and a plurality of DUs 23-4 to 23-6. In this embodiment, the plurality of DUs 23-1 to 23-3 form a cell 200-1, the plurality of DUs 23-4 to 23-5 form a cell 200-2, and the DU 23-6 includes a cell 200-1. -3. Hereinafter, each of the plurality of DUs 23-1 to 23-6 is collectively referred to as DU23 without being distinguished. Each CU 22 is an example of a communication control device, and each DU 23 is an example of a wireless device.

In the example of FIG. 13, the wireless communication system 10 includes two base stations 20, but the wireless communication system 10 may include three or more base stations 20. In the example of FIG. 13, one base station 20 includes one CU 22 and three DUs 23, but the number of CUs 22 and DUs 23 included in one base station 20 is not limited to this. Each CU 22 is realized by a control device such as BBU, and each 23 is realized by a radio device such as RRH.

[Base station 20m]
FIG. 14 is a block diagram illustrating an example of a base station 20m that functions as a master base station in the fourth embodiment. For example, as illustrated in FIG. 14, the CU 22 of the base station 20 m includes a communication unit 220, a control unit 221, a memory 222, and a communication unit 223. Except for the points described below, in FIG. 14, blocks denoted by the same reference numerals as those in FIG. 2 have the same or similar functions as the blocks in FIG.

In the memory 222, for example, base station information 2120 as shown in FIG. 15 is stored. FIG. 15 is a diagram illustrating an example of the base station information 2120 according to the fourth embodiment. In the base station information 2120 in this embodiment, CU_ID, access information, and DU_ID are stored in association with the cell ID. The CU_ID is information for identifying the CU 22 that manages the DU 23 that manages the cell 200 having the associated cell ID. The access information is information for accessing the CU 22 identified by the corresponding CU_ID, such as address information. The DU_ID is information for identifying the DU 23 that manages the cell 200 having the associated cell ID. When one cell 200 is formed by a plurality of DUs 23, a plurality of DU_IDs are associated with one cell ID. The base station information 2120 is stored in the memory 222 in advance by an administrator of the base station 20 or the like. The memory 222 stores various programs executed by the control unit 221.

The control unit 221 executes a program read from the memory 222, thereby executing a DC execution determination unit 2110, a request unit 2111, a collection unit 2112, a DC availability determination unit 2113, a selection unit 2114, a DC processing unit 2115, and a wireless communication control. Each function of the unit 2116 is realized.

The DC execution determination unit 2110 determines whether or not communication with the terminal device 30 is executed by DC. The DC execution determination unit 2110 determines whether or not to perform communication with the terminal device 30 by DC based on, for example, the resource statuses of the CU 22 and the respective DUs 23 included in the base station 20.

The collection unit 2112 collects resource information including information indicating the state of the resources of the CU 22 and the DU 23 for each cell ID from each of the other base stations 20.

The DC availability determination unit 2113 determines whether DC is possible for each combination of the CU 22 and the DU 23 based on the resource information collected by the collection unit 2112. Then, the DC availability determination unit 2113 outputs DC information indicating the determination result to the selection unit 2114.

The selection unit 2114 acquires DC information from the DC availability determination unit 2113 for each combination of the CU 22 and the DU 23 of the other base station 20 before the DC is requested to the other base station 20. Based on the DC information output from the DC availability determination unit 2113, the selection unit 2114 selects the CU 22 that requests DC from the combination of the CU 22 and DU 23 corresponding to the DC information indicating that DC is possible. A combination of DUs 23 is selected. For example, the selection unit 2114 preferentially selects a combination including the DU 23 that manages the cell 200 with good signal quality from among the combinations of the CU 22 and the DU 23 corresponding to DC information indicating that DC is possible. . Then, the selection unit 2114 outputs information on the selected combination to the DC processing unit 2115.

The DC processing unit 2115 transmits a DC request, which is a control signal for requesting DC, to the CU 22 included in the combination selected by the selection unit 2114 via the communication unit 210 and the core network 11. The DC request includes information regarding the combination of the CU 22 and the DU 23 that requests DC.

The wireless communication control unit 2116 executes processing of a higher layer protocol among the wireless control protocols. In the present embodiment, the radio communication control unit 2116 executes, for example, processing of an upper layer (RRC layer, PDCP layer, RLC layer, and MAC layer) in LLS (Low Layer Split). Note that the wireless communication control unit 2116 may execute part of the physical layer processing. Further, the wireless communication control unit 2116 may execute processing of higher layers (RRC layer and PDCP layer) in HLS (High Layer Split), for example.

The communication unit 223 transmits and receives signals by optical communication between the CU 22 and each DU 23 according to a communication standard such as CPRI (Common Public Radio Interface).

Each DU 23 includes a communication unit 230, a radio unit 231, a control unit 232, a memory 233, and an antenna 234. The communication unit 230 transmits and receives signals by optical communication between the DU 23 and the CU 22 according to a communication standard such as CPRI.

In the memory 233, for example, various programs executed by the control unit 232 are stored. The control unit 232 includes a processor such as a CPU or a DSP, for example, and implements each function of the control unit 232 by executing a program read from the memory 233.

The radio unit 231 transmits the radio signal via the antenna 234, thereby forming the cell 200 in a range where the radio signal reaches. In addition, the radio unit 231 executes a lower layer protocol process of the radio control protocol on the signal output from the CU 22 via the communication unit 230 and the signal received via the antenna 234. . In the present embodiment, the wireless unit 231 executes, for example, processing of a lower layer (physical layer) in LLS. Note that the wireless unit 231 may execute part of the physical layer processing. Further, the radio unit 231 may execute processing of lower layers (RLC layer, MAC layer, and physical layer) in HLS, for example. The wireless unit 231 is an example of a transmission unit, a reception unit, and a transmission / reception unit.

As described above, the radio unit 231 of the DU 23 can perform DC based on the DC information acquired for each of the plurality of other base stations 20 before DC is requested to the other base station 20. The other base station 20 requesting the DC is selected from the other base stations 20 corresponding to the DC information indicating the DC, and the DC is requested among the communication traffic with the terminal device 30 performed by the DC. Data based on the remaining communication traffic excluding communication traffic of other base stations is transmitted to and received from the terminal device 30 by wireless communication.

[Base station 20s]
FIG. 16 is a block diagram illustrating an example of a base station 20s functioning as a secondary base station in the fourth embodiment. Except for the points described below, in FIG. 16, blocks denoted by the same reference numerals as those in FIG. 4 or FIG. 14 have the same or similar functions as the blocks in FIG. The control unit 221 of the base station 20 s according to the fourth embodiment implements the functions of the DC processing unit 2115, the wireless communication control unit 2116, and the resource management unit 2117 by executing the program read from the memory 222.

When the resource management unit 2117 receives a resource information request from the base station 20m via the core network 11 and the communication unit 210, the resource management unit 2117 transmits the resource information request to each DU 23 in the base station 20s via the communication unit 223. . Then, the resource management unit 2117 acquires resource information from each DU 23 via the communication unit 223. Then, the resource management unit 2117 transmits resource information indicating the resource status of the CU 22 and each DU 23 in the base station 20 s to the base station 20 m via the communication unit 210 and the core network 11.

FIG. 17 is a diagram illustrating an example of data included in the resource information 50 in the fourth embodiment. In the resource information 50 transmitted from each base station 20s to the base station 20m, for example, as shown in FIG. 17, CU_ID, CU resource information, DU_ID, and DU resource information are stored in association with the cell ID. The The CU resource information is resource information of the CU 22 corresponding to the CU_ID. The DU resource information is resource information of the DU 23 corresponding to the DU_ID. When one cell 200 is formed by a plurality of DUs 23, a plurality of pairs of DU_ID and DU resource information are associated with one cell ID.

Each DU 23 is the same as the DU 23 described in FIG. 14 except for the points described below, and thus detailed description thereof is omitted. When the control unit 232 receives a resource information request from the CU 22 via the communication unit 230, the control unit 232 transmits resource information indicating the state of the resource in the DU 23 to the CU 22 via the communication unit 230. Further, when receiving a DC request from the CU 22, the control unit 232 returns an ACK to the CU 22 if the DC is possible, and returns a NACK (Negative ACKnowledgement) to the CU 22 if the DC is difficult.

[Processing of Radio Communication System 10]
FIG. 18 is a diagram illustrating an example of processing of the wireless communication system 10 according to the fourth embodiment. In the example of FIG. 18, a radio communication system 10 including one terminal device 30, one base station 20m that functions as a master base station, and one base station 20s that functions as a candidate for a secondary base station is assumed. . However, the radio communication system 10 may include a plurality of base stations 20s. In the example of FIG. 18, the terminal device 30 is located in the cell 200 formed by the DU 23-1 in the base station 20m.

First, whether the CU 22-1 of the base station 20m functioning as the master base station performs communication with the terminal device 30 by DC based on the resource state of the CU 22-1 and each DU 23 in the base station 20m. Determine whether or not. Then, the CU 22-1 determines to perform communication with the terminal device 30 by DC (S200). Then, the CU 22-1 transmits the MR request to the DU 23 (DU 23-1 in the example of FIG. 18) that communicates with the terminal device 30 by DC (S201). The DU 23-1 transmits the MR request transmitted from the CU 22-1 to the terminal device 30 by a radio signal (S202).

When the terminal device 30 receives the MR request, the terminal device 30 measures the quality of the signal transmitted from the base station 20 in the surrounding cell 200. Then, the terminal device 30 creates an MR including quality information indicating the quality of the signal for each surrounding cell 200, and transmits the created MR to the DU 23-1 (S203).

When receiving the MR from the terminal device 30, the DU 23-1 transfers the received MR to the CU 22-1 (S204). Based on the quality information for each cell 200 included in the MR transferred from the DU 23-1, the CU 22-1 specifies one or more base stations 20s that are the transmission destinations of the resource information request (S205). Then, the CU 22-1 transmits a resource information request to the CU 22-2 of the specified base station 20s via the core network 11 (S206). When a plurality of base stations 20s as transmission destinations of resource information requests are specified, the resource information requests are transmitted to the CU 22-2 of each base station 20s by, for example, multicast.

When receiving the resource information request from the base station 20m via the core network 11, the CU 22-2 of each base station 20s transmits the resource information request to each DU 23 in the base station 20s (S207-1 to S207). -3). When receiving each resource information request from the CU 22-2, each DU 23 transmits resource information indicating the state of the resource in the DU 23 to the CU 22-2 (S208-1 to S208-3). The CU 22-2 transmits resource information indicating the state of the resources of the CU 22-2 and each DU 23 in the base station 20s to the base station 20m via the core network 11 (S209).

Next, the CU 22-1 of the base station 20m determines whether or not DC is possible for each combination of the CU 22 and the DU 23 based on the resource information received from the base station 20s (S210). Then, the CU 22-1 selects the combination of the CU 22 and the DU 23 that requests DC from the combination of the CU 22 and the DU 23 that can be DC (S211). The CU 22-1 selects, for example, a combination including the DU 23 that manages the cell 200 having the best quality of the signal received by the terminal device 30 among the combinations of the CU 22 and the DU 23 of the base station 20s capable of DC. . In the example of FIG. 18, the DU 23-4 is the DU 23 that manages the cell 200 with the best quality of the signal received by the terminal device 30.

Then, the CU 22-1 transmits a DC request, which is a control signal for requesting DC, to the CU 22 (CU 22-2 in the example of FIG. 18) included in the combination selected in step S211 via the core network 11. (S212). The CU 22-2 that has received the DC request transfers the DC request to the DU 23-4 (S213). The DU 23-4 transmits an ACK indicating acceptance of the DC request to the CU 22-2 (S214). The CU 22-2 transmits ACK indicating acceptance of the DC request to the CU 22-1 via the core network 11 (S215). Then, the base station 20m and the base station 20s-1 cooperate to execute wireless communication with the terminal device 30 by DC.

[Effect of Example 4]
In the above, Example 4 was demonstrated. As described above, the base station 20 of this embodiment includes the CU 22 and a plurality of DUs 23. The CU 22 that requests DC to the CU 22 of another base station 20 can perform DC for each combination of the CU 22 and DU 23 in each other base station 20 before requesting DC to the other base station 20. DC information indicating whether or not is collected. Then, the CU 22 that requests DC to the CU 22 of another base station 20 specifies the combination of the CU 22 and DU 23 that requests DC based on the collected DC information, and sends the DC to the CU 22 included in the specified combination. Ask. Thereby, the base station 20 of a present Example can raise possibility that a DC request | requirement will be accepted, and can establish DC more rapidly.

In the fourth embodiment, the CU processes both control plane data and user plane data. In contrast, in the fifth embodiment, CU-CP (Central Unit-C-Plane) mainly processes control plane data, and CU-UP (Central Unit-U-Plane) mainly processes user plane data. Is different from the fourth embodiment.

[Wireless communication system 10]
FIG. 19 is a diagram illustrating an example of the wireless communication system 10 according to the fifth embodiment. The wireless communication system 10 includes a plurality of base stations 20 and a terminal device 30. Each base station 20 is connected to the core network 11, controls the wireless connection of the terminal device 30, and relays communication between the terminal device 30 and the core network 11.

The base station 20-1 has a CU-CP 24, a plurality of CU-UPs 25-1 to 25-2, and a plurality of DUs 23-1 to 6. In this embodiment, the CU-UP 25-1 is connected to DUs 23-1 to 23-3, and the CU-UP 25-2 is connected to DUs 23-4 to 23-6. In this embodiment, the plurality of DUs 23-1 to 23-3 form the cell 200-1, the plurality of DUs 23-4 to 23-5 form the cell 200-2, and the DU 23-6 A cell 200-3 is formed. In the following, a plurality of CU-UPs 25-1 to 25-2 are collectively referred to as CU-UP25 without being distinguished, and a plurality of DUs 23-1 to 23-6 are not distinguished from each other. When referring generically, it is described as DU23. The CU-CP 24 is an example of a communication control device, and each DU 23 is an example of a wireless device.

In the example of FIG. 18, one CU-CP 24, two CU-UPs 25, and six DUs 23 are provided in each base station 20, but the CU-CP 24, CU-UP 25, and DU 23 The number is not limited to this. The CU-CP 24 and each CU-UP 25 are realized by a control device such as BBU, for example, and each DU 23 is realized by a radio device such as RRH, for example. Note that the CU-CP 24 or each CU-UP 25 may be included in a radio apparatus such as an RRH. Further, the CU-CP 24 and each CU-UP 25 may be realized in separate control devices.

[CU-CP24]
FIG. 20 is a block diagram illustrating an example of the CU-CP 24 according to the fifth embodiment. The CU-CP 24 includes a communication unit 240, a control unit 241, a memory 242, and a communication unit 243, for example, as shown in FIG. Except for the points described below, in FIG. 20, blocks denoted by the same reference numerals as those in FIG. 2 or FIG. 11 have the same or similar functions as the blocks in FIG.

In the memory 242, base station information 2120 as shown in FIG. 21, for example, is stored. FIG. 21 is a diagram illustrating an example of the base station information 2120 according to the fifth embodiment. In the base station information 2120 in this embodiment, CU-CP_ID, access information, and DU_ID are stored in association with the cell ID. The CU-CP_ID is information for identifying the CU-CP 24 that manages the CU-UP 25 that transmits and receives user data via the DU 23 that manages the cell 200 corresponding to the cell ID. The access information is information for accessing the CU-CP 24 identified by the corresponding CU-CP_ID, such as address information. When one cell 200 is formed by a plurality of DUs 23, a plurality of DU_IDs are associated with one cell ID. The base station information 2120 is stored in the memory 242 in advance by an administrator of the base station 20 or the like. In the memory 242, various programs executed by the control unit 241 are stored.

The control unit 241 executes each program of the DC execution determination unit 2110, the collection unit 2112, the DC availability determination unit 2113, the selection unit 2114, the DC processing unit 2115, and the wireless communication control unit 2116 by executing the program read from the memory 242. Realize the function.

The collection unit 2112 collects resource information including information indicating the state of the resources of the CU-UP 25 and the DU 23 for each cell ID from each CU-UP 25. Then, the collection unit 2112 stores the collected resource information in the resource information 2121 in the memory 242.

FIG. 22 is a diagram illustrating an example of data included in the resource information 51 in the fifth embodiment. The memory 212 collects resource information 51 as shown in FIG. 22 from each CU-UP 25, for example. The resource information 51 stores CU-UP_ID, CU-UP resource information, DU_ID, and DU resource information in association with the cell ID. The CU-UP_ID is information for identifying the CU-UP 25 that transmits and receives user data via the DU 23 that manages the cell 200 corresponding to the cell ID. The CU-UP resource information is resource information of the CU-UP 25 corresponding to the CU-UP_ID. The DU resource information is resource information of the DU 23 corresponding to the DU_ID. When one cell 200 is formed by a plurality of DUs 23, a plurality of pairs of DU_ID and DU resource information are associated with one cell ID.

The DC execution determination unit 2110 refers to the resource information 2121 in the memory 242, and determines whether or not to perform communication with the terminal device 30 by DC based on the resource statuses of the CU-UP 25 and the DU 23, respectively. judge.

The DC availability determination unit 2113 determines whether DC is possible for each combination of the CU-UP 25 and the DU 23 based on the resource information collected by the collection unit 2112. Then, the DC availability determination unit 2113 outputs DC information indicating the determination result to the selection unit 2114.

The selection unit 2114 acquires DC information from the DC availability determination unit 2113 for each combination of the CU-UP 25 and the DU 23 before DC is requested to the DU 23. Based on the DC information output from the DC availability determination unit 2113, the selection unit 2114 selects the CU that requests DC from the combination of the CU-UP 25 and the DU 23 corresponding to the DC information indicating that DC is possible. -Select the combination of UP25 and DU23. For example, among the combinations of CU-UP 25 and DU 23 corresponding to DC information indicating that DC is possible, the selection unit 2114 preferentially selects a combination including the DU 23 that manages the cell 200 with good signal quality. select. Then, the selection unit 2114 outputs information related to the selected combination of the CU-UP 25 and the DU 23 to the DC processing unit 2115.

The DC processing unit 2115 transmits a control signal for requesting DC to the CU-UP 25 included in the combination selected by the selection unit 2114. The control signal for requesting DC includes information on the combination of CU-UP 25 and DU 23 for requesting DC.

The radio communication control unit 2116 executes processing of the upper layer protocol in the control plane among the radio control protocols. In the present embodiment, the radio communication control unit 2116 executes, for example, processing of an upper layer (RRC layer, PDCP-C layer, RLC-C layer, and MAC-C layer) of a control plane in LLS. Note that the wireless communication control unit 2116 may execute part of the physical layer processing. Further, the radio communication control unit 2116 may execute processing of higher layers (RRC-C layer and PDCP-C layer) in HLS, for example.

The communication unit 243 performs transmission and reception of signals by optical communication with each CU-UP 25 according to a communication standard such as CPRI.

[CU-UP25]
FIG. 23 is a block diagram illustrating an example of the CU-UP 25 according to the fifth embodiment. The CU-UP 25 includes a communication unit 250, a control unit 251, a memory 252, and a communication unit 253, for example, as shown in FIG. Except for the points described below, in FIG. 23, blocks denoted by the same reference numerals as those in FIG. 4 have the same or similar functions as the blocks in FIG. The communication unit 250 is an example of a transmission unit, a reception unit, and a transmission / reception unit.

In the memory 252, various programs executed by the control unit 251 are stored. The control unit 251 implements the functions of the DC processing unit 2115, the resource management unit 2117, and the wireless communication control unit 2118 by executing the program read from the memory 252.

The resource management unit 2117 manages the resource status of each subordinate DU 23. Further, the resource management unit 2117 transmits the resource information to the CU-CP 24 via the communication unit 250 at every predetermined timing. The predetermined timing is, for example, a timing at which the resource state has changed by a predetermined amount or more in the CU-UP 25 or each DU 23. As a result, communication traffic for collecting resource information can be reduced between the CU-CP 24 and each CU-UP 25. The predetermined timing may be a periodic timing.

The wireless communication control unit 2118 executes processing of the upper layer protocol in the user plane among the wireless control protocols. In the present embodiment, the radio communication control unit 2118 executes, for example, processing of upper layers (PDCP-U layer, RLC-U layer, and MAC-U layer) of the user plane in LLS. Note that the wireless communication control unit 2116 may execute part of the physical layer processing. Further, the radio communication control unit 2116 may execute processing of an upper layer (PDCP-U layer) in HLS, for example.

The communication unit 253 transmits and receives signals by optical communication between the CU-UP 25 and each DU 23 in accordance with a communication standard such as CPRI.

Each DU 23 is the same as the DU 23 described in FIG. 14 except for the points described below, and thus detailed description thereof is omitted. When the control unit 232 of each DU 23 receives a resource information request from the CU-UP 25 via the communication unit 230, resource information indicating the state of the resource in the DU 23 is transmitted to the CU-UP 25 via the communication unit 230. Send. Also, when receiving a DC request from the CU-UP 25, the control unit 232 returns ACK to the CU-UP 25 if DC is possible, and returns NACK to the CU-UP 25 if DC is difficult.

[Processing of Radio Communication System 10]
FIG. 24 is a diagram illustrating an example of processing of the wireless communication system 10 according to the fifth embodiment.

First, when each DU 23 detects that the state of the resource has changed by a predetermined amount or more, each DU 23 transmits resource information to the CU-UP 25 (S300, S301). Each CU-UP 25 transmits the resource information received from the DU 23 to the CU-CP 24 including information indicating the resource state of the CU-UP 25 (S302, S303). The CU-CP 24 stores the resource information transmitted from each CU-UP 25. The resource information transmitted in steps S300 to S303 is determined based on whether or not communication with the terminal device 30 is executed by DC and whether or not DC can be executed for each combination of the CU-UP 25 and the DU 23. Used for both.

The CU-CP 24 determines whether or not to communicate with the terminal device 30 by DC based on the resource information transmitted from each CU-UP 25. When the CU-CP 24 decides to execute communication with the terminal device 30 by DC (S304), the CU-CP 24-1 communicates with the DU 23-1 that communicates with the terminal device 30 by DC. (S305). The CU-UP 25-1 transfers the MR request transmitted from the CU-CP 24 to the DU 23-1 (S306). The DU 23-1 transmits the MR request transmitted from the CU-UP 25-1 to the terminal device 30 using a radio signal (S307).

When the terminal device 30 receives the MR request, the terminal device 30 measures the quality of the signal transmitted from the base station 20 in the surrounding cell 200. Then, the terminal device 30 creates an MR including quality information indicating the quality of the signal for each surrounding cell 200, and transmits the created MR to the DU 23-1 (S308). The DU 23-1 transfers the MR received from the terminal device 30 to the CU-UP 25-1 (S309). The CU-UP 25-1 transfers the MR received from the DU 23-1 to the CU-CP 24 (S310).

CU-CP 24 determines whether or not DC is possible for each combination of CU-UP 25 and DU 23 based on the latest resource information collected from each CU-UP 25 (S311). Then, the CU-CP 24 selects a combination of the CU-UP 25 and the DU 23 that is a transmission destination of the DC request from among the combinations of the CU-UP 25 and the DU 23 that can perform DC (S312). For example, the CU-CP 24 preferentially selects a combination including the DU 23 that manages the cell 200 having the best quality of the signal received by the terminal device 30 among the combinations of the CU-UP 25 and the DU 23 in which DC is possible. To do. In the example of FIG. 24, the DU 23-4 is the DU 23 that manages the cell 200 having the best signal quality received by the terminal device 30.

Then, the CU-CP 24 sends a DC request including information on the combination of the CU 22 and the DU 23 that requests DC to the CU-UP 25 (CU-UP 25-2 in the example of FIG. 24) included in the combination selected in step S312. (S313). Upon receiving the DC request, the CU-UP 25-2 receives the DC request and transmits the DC request to the DU 23 (DU 23-4 in the example of FIG. 24) corresponding to the combination included in the DC request (S314). Upon receiving the DC request, the DU 23-4 transmits an ACK to the CU-UP 25-2 when accepting the DC request (S315). When ACK is received from DU 23-4, CU-UP 25-2 transmits ACK to CU-CP 24 (S316). The CU-UP 25-1 and DU 23-1, and the CU-UP 25-2 and DU 23-4 cooperate to execute wireless communication with the terminal device 30 through DC.

[Effect of Example 5]
The fifth embodiment has been described above. As described above, the base station 20 of this embodiment includes the CU-CP 24, the plurality of CU-UPs 25, and the plurality of DUs 23. When performing DC between the DUs 23, the CU-CP 24 collects DC information indicating whether or not DC is possible for each combination of the CU-UP 25 and the DU 23 before requesting the DC to the DU 23. . Then, the CU-CP 24 specifies a combination of the CU-UP 25 and the DU 23 that requests DC based on the collected DC information, and requests the DC from the CU-UP 25 included in the specified combination. Thereby, the base station 20 of a present Example can raise possibility that a DC request | requirement will be accepted, and can establish DC more rapidly.

In the fifth embodiment described above, the CU-CP 24 uses the resource information transmitted at a predetermined timing from each CU-UP 25 to determine whether or not to perform communication with the terminal device 30 by DC, and Both the determination as to whether or not the DC can be executed is performed. On the other hand, in the sixth embodiment, the CU-CP 24 uses the first resource information transmitted from each CU-UP 25 at a predetermined timing to determine whether or not to execute communication with the terminal device 30 by DC. Judgment is made. Further, the second resource information used for determining whether or not DC can be executed is collected after it is determined that communication with the terminal device 30 is executed by the DC.

For example, information on the buffer capacity and the capacity of each interface is collected as the first resource information, and in addition to the first resource information, the processor and memory usage rates are collected as the second resource information. Thereby, the data amount of 1st resource information can be made smaller than the data amount of 2nd resource information. Further, the second resource information is collected from the other base station 20 specified based on the MR received from the terminal device 30. As a result, it is possible to reduce communication traffic in the collection of resource information among the CU-CP 24, each CU-UP 25, and each DU 23.

[CU-CP24]
FIG. 25 is a block diagram illustrating an example of the CU-CP 24 according to the sixth embodiment. Except for the points described below, in FIG. 25, blocks denoted by the same reference numerals as those in FIG. 20 have the same or similar functions as the blocks in FIG.

The collection unit 2112 stores the first resource information and the second resource information transmitted from each CU-UP 25 in the resource information 2121 in the memory 242.

The DC execution determination unit 2110 refers to the first resource information included in the resource information 2121 in the memory 242, and based on the resource statuses of the CU-UP 25 and the respective DUs 23, the DC execution determination unit 2110 communicates with the terminal device 30 by the DC. It is determined whether to execute communication. If the resource information 2121 includes the second resource information, the DC execution determination unit 2110 may determine whether to perform communication with the terminal device 30 by using the DC.

When receiving the MR from the terminal device 30, the request unit 2111 has one CU-UP 25 as a transmission destination of the resource information request for requesting the second resource information based on the quality information for each cell 200 included in the MR. The above is specified. Then, the request unit 2111 transmits a resource information request to the identified CU-UP 25 via the communication unit 243. The resource information request includes information on the DU 23. The resource information request is transmitted by multicast, for example.

The request unit 2111 specifies, for example, a CU-UP 25 that communicates with the DU 23 that manages each cell 200 as the CU-UP 25 that is the transmission destination of the resource information for a predetermined number of cells 200 in order of good signal quality. . In addition, for example, for the cell 200 having better signal quality than the predetermined quality, the request unit 2111 sets the CU-UP 25 that communicates with the DU 23 that manages each cell 200 as the CU-UP 25 that is the transmission destination of the resource information request. You may specify.

The DC availability determination unit 2113 refers to the resource information 2121 in the memory 242 and determines whether DC is possible for each combination of the CU-UP 25 and the DU 23. Whether or not DC is possible is determined based on the second resource information. Then, the DC availability determination unit 2113 outputs DC information indicating the determination result to the selection unit 2114.

[CU-UP25]
Each CU-UP 25 is the same as the CU-UP 25 described with reference to FIG. 23 except for the points described below, and a detailed description thereof will be omitted. The resource management unit 2117 transmits the first resource information to the CU-CP 24 via the communication unit 250 at every predetermined timing. When the resource management unit 2117 receives a resource information request from the CU-CP 24 via the communication unit 250, the resource management unit 2117 transmits the second resource information to the CU-CP 24 via the communication unit 250.

[Processing of Radio Communication System 10]
FIG. 26 is a diagram illustrating an example of processing of the wireless communication system 10 according to the sixth embodiment. Except for the points described below, in FIG. 26, the processes denoted by the same reference numerals as those in FIG. 24 are the same as the processes described in FIG.

First, when each DU 23 detects that the state of the resource corresponding to the item included in the first resource information has changed by a predetermined amount or more, it transmits the first resource information to the CU-UP 25 (S300, S301). ). Each CU-UP 25 transmits the first resource information received from the DU 23 to the CU-CP 24 including information indicating the state of the resource of the CU-UP 25 corresponding to the item included in the first resource information ( S302, S303). The CU-CP 24 stores the resource information transmitted from each CU-UP 25.

The CU-CP 24 determines whether or not to communicate with the terminal device 30 by DC based on the resource information transmitted from each CU-UP 25. When the CU-CP 24 decides to execute communication with the terminal device 30 by DC (S304), the CU-CP 24-1 communicates with the DU 23-1 that communicates with the terminal device 30 by DC. (S305).

When receiving the MR from the CU-UP 25-1, the CU-CP 24 specifies one or more CU-UPs 25 to which the resource information request is transmitted based on the quality information for each cell 200 included in the MR (S320). . Then, the CU-CP 24 transmits a resource information request to the specified CU-UP 25 (S321). The resource information request is transmitted by multicast, for example.

When each CU-UP 25 receives the resource information request from the CU-CP 24, each CU-UP 25 collects the second resource information from the DU 23 included in the resource information request (S322, S324). Then, each CU-UP 25 transmits the second resource information received from the DU 23 to the CU-CP 24 including information indicating the resource status of the CU-UP 25 corresponding to the item included in the second resource information. (S303, S305). The CU-CP 24 stores the second resource information transmitted from each CU-UP 25. And the radio | wireless communications system 10 performs the process after step S311.

[Effect of Example 6]
The example 6 has been described above. As described above, in this embodiment, it is determined whether or not communication with the terminal device 30 is executed by the DC using the first resource information transmitted from each CU-UP 25 at a predetermined timing. Is called. Further, the second resource information used for determining whether or not DC can be executed is collected after it is determined that communication with the terminal device 30 is executed by the DC. The data amount of the first resource information can be made smaller than the data amount of the second resource information. Thereby, it is possible to reduce communication traffic in the collection of resource information among the CU-CP 24, each CU-UP 25, and each DU 23.

[Others]
The disclosed technology is not limited to the above-described embodiments, and various modifications can be made within the scope of the gist.

For example, in the above-described fourth embodiment, the base station 20m determines whether or not DC is possible in the other base station 20s, but the disclosed technique is not limited thereto. For example, also in the fourth embodiment, for example, as in the second embodiment, another base station 20s may determine whether or not DC is possible.

Further, in the above-described fourth embodiment, resource information is collected from another base station 20 after the execution of DC is determined, but the disclosed technique is not limited to this. For example, also in the fourth embodiment, resource information may be collected from another base station 20 before the execution of DC is determined as in the third embodiment, for example.

In the fifth and sixth embodiments described above, the CU-CP 24 communicates with the CU-UP 25 via the CU-UP 25. However, the disclosed technology is not limited to this, and the CU-CP 24 and each DU 23 are F1. You may communicate via the -C interface.

In the fifth and sixth embodiments described above, the execution of DC between the DUs 23 in one base station 20 has been described as an example, but the disclosed technology is not limited to this. For example, even when DC is performed between DUs 23 provided in different base stations 20, the technique disclosed in the fifth or sixth embodiment can be applied.

In the fifth and sixth embodiments described above, it is determined whether or not the CU-CP 24 executes DC. However, the disclosed technique is not limited to this, and whether or not each CU-UP 25 executes DC. May be determined.

In Embodiments 5 and 6 described above, the CU-CP 24 determines whether or not DC is possible in each combination of the CU-UP 25 and the DU 23, but the disclosed technology is not limited thereto. For example, the CU-CP 24 may transmit a DC determination request to each CU-UP 25, and each CU-UP 25 may determine whether or not DC is possible for each combination of the CU-UP 25 and the DU 23.

In each embodiment described above, each block in the base station 20 may be realized by an independent computer, or may be realized by one computer having one or more memories and processors.

In each of the above-described embodiments, each processing block of the base station 20 is classified by function according to main processing contents in order to facilitate understanding of each device in the embodiment. For this reason, the disclosed technique is not limited by the processing block classification method and its name. In addition, each processing block of the base station 20 can be subdivided into a larger number of processing blocks according to the processing content, or a plurality of processing blocks can be integrated into one processing block. In addition, part or all of the processing executed by each processing block may be realized as software processing, or may be realized by dedicated hardware such as ASIC (Application Specific Integrated Circuit).

10 wireless communication system 11 core network 20 base station 200 cell 210 communication unit 211 control unit 2110 DC execution determination unit 2111 request unit 2112 collection unit 2113 DC availability determination unit 2114 selection unit 2115 DC processing unit 2116 radio communication control unit 2117 resource management unit 2118 Radio communication control unit 212 Memory 2120 Base station information 2121 Resource information 213 Radio unit 214 Antenna 22 CU
220 Communication Unit 221 Control Unit 222 Memory 223 Communication Unit 23 DU
230 Communication Unit 231 Radio Unit 232 Control Unit 233 Memory 234 Antenna 24 CU-CP
240 communication unit 241 control unit 242 memory 243 communication unit 25 CU-UP
250 communication unit 251 control unit 252 memory 253 communication unit 30 terminal device 31 antenna 32 radio unit 33 control unit 330 measurement unit 331 MR processing unit 332 DC processing unit 333 radio communication control unit 34 memory 40 MR
50 Resource information 51 Resource information

Claims

In a communication control apparatus capable of controlling connection of wireless communication,
A wireless communication control unit for controlling communication with the terminal device using the first radio frequency, or for controlling communication with the terminal device via the connected wireless device;
A transmission unit that transmits a signal requesting control information regarding whether communication with the terminal device is possible using a second radio frequency different from the first radio frequency to another communication control device;
A receiving unit for receiving a signal including the control information from the other communication control device;
A selection unit that selects one communication control device that communicates with the terminal device using the second radio frequency from the other communication control device;
The transmitter is
A communication control apparatus, wherein a control signal including information related to communication with the terminal apparatus using the second radio frequency is transmitted to the one communication control apparatus.
The selection unit includes:
The communication control device according to claim 1, wherein the one communication control device that satisfies a required radio channel quality is selected as a radio channel quality with the terminal device.
The transmitter is
Transmitting a signal for requesting resource information related to radio resources used by the one communication control device;
The receiver is
Receiving the resource information from the other communication control device;
The communication control device includes:
The communication control apparatus according to claim 1, further comprising a control unit that controls communication with the terminal apparatus using the second radio frequency and the resource information.
The transmitter is
A signal requesting resource information regarding the radio resource is transmitted to the other communication control device that manages each of the predetermined number of cells in order of good signal quality measured in the terminal device. The communication control device according to claim 3.
The transmitter is
A signal requesting resource information regarding the radio resource is transmitted to the other communication control device that manages each of the cells for which the quality of the signal measured in the terminal device is better than a predetermined quality. The communication control device according to claim 3.
A determination unit that determines whether to perform communication with the terminal device using the second radio frequency;
The receiver is
Before it is determined by the determination unit to execute communication with the terminal device at the second radio frequency, resource information related to the radio resource is received from the other communication control device,
The selection unit includes:
When the determination unit determines to execute communication with the terminal device using the second radio frequency, the one of the other communication control devices received by the reception unit according to the latest resource information. The communication control apparatus according to claim 3, wherein a communication control apparatus is selected.
The receiver is
The communication control apparatus according to claim 6, wherein the other communication control apparatus receives the resource information when a radio resource indicated by the resource information changes by a predetermined amount or more.
The transmitter is
Transmitting a determination request for requesting determination as to whether communication by the second radio frequency is possible;
The selection unit includes:
The said one communication control apparatus is selected based on the determination result of whether the communication by the said 2nd radio frequency acquired from the said other communication control apparatus is possible. Communication control device.
In the determination request,
9. The communication control apparatus according to claim 8, further comprising information related to communication traffic allocated to the other communication control apparatus in communication using the second radio frequency.
In a wireless device that connects to a communication control device and communicates with a terminal device using a first wireless frequency,
One communication control device that communicates using the second radio frequency is selected from the other communication control devices, and the one that is used at the second radio frequency among the communication traffic with the terminal device. A wireless device comprising: a wireless unit that transmits and receives data to and from the terminal device by wireless communication according to the remaining communication traffic excluding communication traffic of the communication control device.
Multiple base stations,
A terminal device, and
The base station
A wireless communication control unit for controlling communication with the terminal device using the first radio frequency, or for controlling communication with the terminal device via the connected wireless device;
A transmitting unit that transmits a signal requesting control information regarding whether communication with the terminal device is possible using a second radio frequency different from the first radio frequency to another base station;
A receiving unit for receiving a signal including the control information from the other base station;
A selection unit that selects one base station that communicates with the terminal device using the second radio frequency from the other base station;
The transmitter is
A radio communication system, wherein a control signal including information related to communication with the terminal device using the second radio frequency is transmitted to the one base station.