Wireless communication system, communication control method, and computer program

Abstract

Modify the communication connection between the RU and DU in the fronthaul appropriately. [Solution] In a wireless communication system, the communication control device that controls the communication connection between the RU (Radio Unit) and the DU (Distributed Unit) in an O-RAN specification wireless access network includes an interface for acquiring the round-trip time between the DU and the RU to be measured.

Description

Technical Field

[0001] The present invention relates to a wireless communication system, a communication control method, and a computer program.

Background Art

[0002] The Open Radio Access Network (O-RAN) Alliance is considering the opening and intelligentization of next-generation radio access networks (RANs) such as the 5th generation (5G) mobile communication system (see, for example, Non-Patent Documents 1-4). The O-RAN specifications established by the O-RAN Alliance define, for example, technologies related to fronthaul.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Summary of the Invention

[0004] However, the conventional O-RAN specification described above could not determine whether the communication connection between the RU (Radio Unit) and DU (Distributed Unit) in the fronthaul met the delay constraints between the RU and DU when changing the communication connection between them in the fronthaul. As a result, it was sometimes difficult to properly change the communication connection between the RU and DU in the fronthaul.

[0005] This invention has been made in consideration of these circumstances, and its purpose is to appropriately modify the communication connection between the RU and DU in the front haul. [Means for solving the problem]

[0006] One aspect of the present invention is a wireless communication system in which a communication control device that controls the communication connection between a Radio Unit (RU) and a Distributed Unit (DU) in an O-RAN specification wireless access network is equipped with an interface for acquiring the round-trip time between the DU and the RU to be measured. One aspect of the present invention is a wireless communication system in which the interface includes a round-trip time measurement instruction from the communication control device to the measurement target DU and a round-trip time response from the measurement target DU to the communication control device. One aspect of the present invention is a wireless communication system in which the interface includes notification from the DU under measurement to the communication control device of a combination of RU and DU that satisfies delay constraints between the RU and DU in the fronthaul. One aspect of the present invention is a wireless communication system in which the RU and the DU can communicate with each other via the same fronthaul network domain. One aspect of the present invention is a wireless communication system in which the interface includes obtaining the round trip time via an A1 interface between a "Non-RT RIC" and a "Near-RT RIC". One aspect of the present invention is a wireless communication system in which the interface includes obtaining the round trip time via an E2 interface between the DU and the "Near-RT RIC". One aspect of the present invention is a wireless communication system in which the interface includes obtaining the round trip time via an O1 interface between the DU and the "Non-RT RIC".

[0007] One aspect of the present invention is a communication control method performed by a wireless communication system, wherein in an O-RAN specification wireless access network, a communication control device that controls the communication connection between a Radio Unit (RU) and a Distributed Unit (DU) via a predetermined interface acquires the round-trip time between the DU and the RU to be measured.

[0008] One aspect of the present invention is a computer program that causes a computer to perform the step of obtaining the round-trip time between a DU and a RU to be measured, which is controlled by a communication control device that controls the communication connection between a RU (Radio Unit) and a DU (Distributed Unit) via a predetermined interface in an O-RAN specification wireless access network. [Effects of the Invention]

[0009] According to the present invention, the effect is obtained that the communication connection between the RU and DU in the front haul can be appropriately modified. [Brief explanation of the drawing]

[0010] [Figure 1]This block diagram shows a schematic example of the configuration of a wireless access network in a wireless communication system according to one embodiment. [Figure 2] This figure shows an example of the procedure for a communication control method according to one embodiment. [Figure 3] This figure shows an example of vDU scaling control in a fronthaul according to one embodiment. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a block diagram showing a schematic configuration example of a radio access network (RAN) of a wireless communication system according to one embodiment. The RAN1 shown in Figure 1 conforms to the O-RAN specification. However, in this embodiment, a fronthaul interface, which is not specified in the O-RAN specification, is newly added.

[0012] RAN1 comprises an RIC (RAN Intelligent Controller) 10 (communication control device), vDUs (virtual DUs) 20 (20-1, 20-2) located in station buildings 200 (200-1, 200-2), a fronthaul network domain 30, and RUs 40 (40-1, 40-2, 40-3, 40-4, 40-5, 40-6).

[0013] RIC10 and station 200 are configured to communicate via a communication line. Station 200 and RU40 are configured to communicate via the fronthaul network domain 30. The fronthaul network domain 30 is, for example, an Ethernet (registered trademark) domain.

[0014] RIC10 controls the communication connection between RUs and DUs in an O-RAN-compliant wireless access network.

[0015] The vDU20 implements signal processing functions such as digital signal modulation / demodulation and encoding, which are functions of the DU. The vDU20 is implemented by computer hardware such as a CPU (Central Processing Unit) and memory provided in its own local site 200.

[0016] In the example of FIG. 1, two local sites 200-1 and 200-2 are shown. The local sites 200-1 and 200-2 are located at different places. Therefore, the communication delay between the vDU20-1 provided in the local site 200-1 and the vDU20-2 provided in the local site 200-2 with a single RU40, for example, RU40-1, may be different. For this reason, even for the same RU40-1, even if one of the vDU20-1 satisfies the delay constraint between the RU and the DU in the fronthaul, the other vDU20-2 may not satisfy the said delay constraint.

[0017] In this embodiment, in RAN1, it is intended to determine a combination of the RU40 and the vDU20 that satisfies the delay constraint between the RU and the DU in the fronthaul. In particular, it is intended to determine whether a combination of the RU40 and the vDU20 that can be communicatively connected via the fronthaul network domain 30 satisfies the said delay constraint.

[0018] For this reason, in this embodiment, the RIC10 is provided with an interface (hereinafter, referred to as the first interface for convenience of explanation) for acquiring the RTT (Round Trip Time) between the vDU20 to be measured and the RU40.

[0019] The RIC10 shown in Figure 1 comprises an acquisition unit 11, a determination unit 12, and a control unit 13 as its functional components. The RIC10 includes a "Non-RT RIC (Non-Real Time RAN Intelligent Controller)" (not shown) and a "Near-RT RIC (Near-Real Time RAN Intelligent Controller)" (not shown), and the functions of the RIC10 are realized by the "Non-RT RIC" and the "Near-RT RIC".

[0020] The acquisition unit 11 acquires the RTT between RU40 and vDU20 via the first interface.

[0021] The determination unit 12 determines, based on the RTT between RU40 and vDU20, which combinations of RU and DU satisfy the delay constraint between RU and DU in the fronthaul. Hereinafter, the delay constraint between RU and DU in the fronthaul may be referred to as the FH delay constraint.

[0022] The control unit 13 controls the communication connection between RU40 and vDU20 based on the determination result of the determination unit 12's determination of a combination of RU and DU that satisfies the FH delay constraint.

[0023] Figure 2 shows an example of the procedure for the communication control method according to this embodiment. The communication control method according to this embodiment will be described with reference to Figure 2.

[0024] (Step S1) The acquisition unit 11 of RIC10 instructs the vDU20 to be measured via the first interface to measure the RTT between the vDU20 and the RU40 (DU-RU RTT measurement instruction).

[0025] The RTT measurement instruction between the DU and RU in the first interface may be newly added to, for example, the E2 interface or O1 interface in the O-RAN specification. The E2 interface is defined in the O-RAN specification as the interface between the "Near-RT RIC" and the DU. The O1 interface is defined in the O-RAN specification as the interface between the "Non-RT RIC" and "Near-RT RIC" and the DU.

[0026] (Step S2) When the vDU20 to be measured receives an RTT measurement instruction between the DU and RU via the first interface, it obtains the addresses of all RU40 in the fronthaul network domain 30 from the fronthaul (FH) ARP (Address Resolution Protocol) table.

[0027] (Step S3) For each RU40 within the fronthaul network domain 30, the vDU20 to be measured performs RTT measurement using the address of the RU40 obtained in Step S2, via the O-RAN specification fronthaul Management Plane (M-Plane) interface (FH-MP).

[0028] (Step S4) For each RU40 in the fronthaul network domain 30, the vDU20 under measurement obtains the RTT measurement response via the O-RAN specification fronthaul management plane interface (FH-MP).

[0029] (Step S5) The vDU20 to be measured responds to the RIC10 via the first interface with the RTT between it and each RU40 obtained in step S4 by the RTT measurement response (RTT response). The acquisition unit 11 of the RIC10 obtains the RTT between the vDU20 to be measured and each RU40 based on the RTT response.

[0030] The RTT response on the first interface may be newly added to, for example, the A1 interface, E2 interface, or O1 interface in the O-RAN specification. The A1 interface is defined in the O-RAN specification as an interface between "Non-RT RIC" and "Near-RT RIC".

[0031] (Step S6) The determination unit 12 of RIC10 determines a combination of RU and DU that satisfies the delay constraint between RU and DU in the fronthaul, based on the RTT between RU40 and vDU20. The control unit 13 of RIC10 controls the communication connection between RU40 and vDU20 based on the result of the determination unit 12's determination of a combination of RU and DU that satisfies the FH delay constraint. For example, the control unit 13 performs scaling control such as scale-out or scale-in using vDU20-1 and 20-2 provided in different buildings 200-1 and 200-2, respectively.

[0032] (Step S7) As a result of controlling the communication connection between RU40 and vDU20 in step S6, the control unit 13 of RIC10 notifies the vDU20 to be controlled of the communication connection setting information with the RU40, the communication partner (DU-RU connection config).

[0033] (Step S8) The controlled vDU20 notifies the RU40, the communication connection partner notified by RIC10, of the communication connection settings information with itself (DU-RU connection config).

[0034] (Step S9) Communication is initiated using the combination of vDU20 and RU40 specified in the DU-RU connection config in Steps S7 and S8.

[0035] Furthermore, the acquisition unit 11 of RIC10 may specify the combination of vDU20 and RU40 for which RTT measurement will be performed in the RTT measurement instruction between DU-RU via the first interface (step S1). In this case, the vDU20 to be measured will perform RTT measurement on RU40 specified in the RTT measurement instruction between DU-RU via the first interface using the O-RAN specification fronthaul management plane interface.

[0036] Furthermore, the vDU20 being measured may notify the RTT response (step S5) via the first interface of a combination of vDU20 and RU40 that satisfies the FH delay constraint. In this case, the acquisition unit 11 of RIC10 receives notification of a combination of vDU20 and RU40 that satisfies the FH delay constraint in the RTT response (step S5) via the first interface.

[0037] According to this embodiment, in an O-RAN specification wireless access network, when changing the communication connection between the RU and DU in the fronthaul, it is possible to determine whether or not the FH delay constraint is satisfied between the RU and DU. This makes it possible to appropriately change the communication connection between the RU and DU in the fronthaul.

[0038] Figure 3 shows an example of vDU scaling control in the fronthaul according to this embodiment. Figure 3(1) shows the case of scaling out from a configuration where only the vDU20-1 of station 200-1 is connected to one RU40, to a configuration where both the vDU20-1 of station 200-1 and the vDU20-2 of station 200-2 are connected. Figure 3(2) shows the case of scaling in from a configuration where both the vDU20-1 of station 200-1 and the vDU20-2 of station 200-2 are connected to one RU40, to a configuration where only the vDU20-1 of station 200-1 is connected.

[0039] Here, we consider a scenario where station 200-1 and station 200-2 are located in different places, and the communication delays between a single RU40, for example RU40-1, and vDU20-1 at station 200-1 and vDU20-2 at station 200-2 are different. In such a case, conventionally, RIC10 could not obtain the RTT between RU40-1 and vDU20-1, nor between RU40-1 and vDU20-2, and therefore could not determine whether the combination of RU40-1 and vDU20-1 and the combination of RU40-1 and vDU20-2 satisfied the FH delay constraint. As a result, when RIC10 scaled out, for example as shown in Figure 3(1), it sometimes scaled out without knowing whether the FH delay constraint was satisfied.

[0040] According to this embodiment, RIC10 can obtain the RTT between RU40-1 and vDU20-1 and the RTT between RU40-1 and vDU20-2 via the first interface, and can determine whether the combination of RU40-1 and vDU20-1 and the combination of RU40-1 and vDU20-2 satisfy the FH delay constraint. As a result, RIC10 can scale out, for example as shown in Figure 3(1), on the condition that the FH delay constraint is satisfied.

[0041] According to this embodiment, even when the RIC10 controls the communication connections of multiple vDU20s located in different locations with different communication delays to a single RU40, it can perform appropriate scaling control according to the number of RUs and user equipment (UEs) that each vDU20 can accommodate.

[0042] According to the embodiment described above, the effect is obtained to appropriately modify the communication connection between the RU and DU in the fronthaul.

[0043] Furthermore, this will enable improvements in overall service quality, such as in wireless communication systems, and will contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs): "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0044] Although embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and design modifications and the like are also included within the scope of the gist of the present invention.

[0045] For example, the embodiment described above was applied to a wireless access network conforming to the O-RAN specification, but it may also be applied to wireless access networks other than those conforming to the O-RAN specification.

[0046] Alternatively, computer programs for realizing the functions of each of the above-mentioned devices may be recorded on a computer-readable recording medium, and the programs recorded on this recording medium may be loaded into a computer system and executed. Note that the term "computer system" here may include hardware such as an operating system and peripheral devices. Furthermore, "computer-readable recording media" refers to writable non-volatile memory such as flexible disks, magneto-optical disks, ROMs, and flash memory, portable media such as DVDs (Digital Versatile Discs), and storage devices such as hard disks built into computer systems.

[0047] Furthermore, "computer-readable recording media" also includes volatile memory (such as DRAM (Dynamic Random Access Memory)) within computer systems that act as servers or clients when programs are transmitted via networks such as the Internet or communication lines such as telephone lines, which retain programs for a certain period of time. Furthermore, the above program may be transmitted from a computer system that stores the program in a memory device or the like to another computer system via a transmission medium or by transmission waves within the transmission medium. Here, the "transmission medium" used to transmit the program refers to a medium that has the function of transmitting information, such as a network (communication network) like the Internet or a communication line (communication line) like a telephone line. Furthermore, the above program may be intended to implement some of the functions described above. It may also be a so-called differential file (differential program) that can implement the aforementioned functions in combination with programs already recorded in the computer system. [Explanation of Symbols]

[0048] 1... Wireless access network, 10... RIC (Communication Control Unit), 11... Acquisition unit, 12... Determination unit, 13... Control unit, 20... vDU, 30... Fronthaul network domain, 40... RU, 200... Station building

Claims

1. In an O-RAN specification wireless access network, a communication control device that controls the communication connection between a Radio Unit (RU) and a Distributed Unit (DU) is equipped with an interface for acquiring the round-trip time between the DU and RU being measured. Wireless communication system.

2. The interface includes a round-trip time measurement instruction from the communication control device to the DU to be measured, and a round-trip time response from the DU to be measured to the communication control device. The wireless communication system according to claim 1.

3. The interface includes notifying the communication control device of the combination of RU and DU that satisfies the delay constraint between the RU and DU in the fronthaul, The wireless communication system according to claim 2.

4. The RU and the DU can communicate with each other via the same fronthaul network domain. A wireless communication system according to any one of claims 1 to 3.

5. The interface includes obtaining the round-trip time via the A1 interface between the "Non-RT RIC" and the "Near-RT RIC". The wireless communication system according to claim 2.

6. The interface includes obtaining the round-trip time via the E2 interface between the DU and the "Near-RT RIC". The wireless communication system according to claim 2.

7. The interface includes obtaining the round-trip time via the O1 interface between the DU and the "Non-RT RIC". The wireless communication system according to claim 2.

8. A communication control method performed by a wireless communication system, In an O-RAN specification wireless access network, a communication control device that controls the communication connection between a Radio Unit (RU) and a Distributed Unit (DU) via a predetermined interface acquires the round-trip time between the DU and RU being measured. Communication control method.

9. On the computer, In an O-RAN specification wireless access network, a communication control device that controls the communication connection between a Radio Unit (RU) and a Distributed Unit (DU) via a predetermined interface acquires the round-trip time between the DU and RU to be measured. A computer program designed to execute something.

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