JP2022089318A - Base station device, mobile communication system, and frequency band control method - Google Patents

Abstract

To provide a base station device and a bandwidth control method that can continuously provide a stable service.SOLUTION: A base station device 100 is included in a non-public cellular network and comprises a communication unit 130 and a control unit 120. The communication unit 130 performs wireless communication with a user device 200 by using a first frequency band shared by the base station device 100 and a stationary station device 400 for public business operations and a second frequency band that cannot be used by the stationary station device 400 for public business operations, or by using the second frequency band without using the first frequency band. When the user device 200 cannot receive a measurement report including a result of measurement of a reference base station device 300 using the first frequency band, the control unit 120 considers that interference occurs with the first frequency band, and controls the communication unit 130 to use the second frequency band without using the first frequency band.SELECTED DRAWING: Figure 1

Description

The present invention relates to a base station device, a mobile communication system, and a frequency band control method.

Recently, the 5th generation mobile communication system that can be used by various actors according to local needs or individual needs is attracting attention. Such a mobile communication system may be referred to as, for example, a local 5G (5th Generation).

In local 5G, apart from the 5G system for the whole country by mobile communication carriers, various entities such as local companies and local governments can build their own spot networks in buildings and premises. Therefore, local 5G is expected to be used for various needs closely related to the region.

On the other hand, in the 3GPP (3rd Generation Partnership Project), which is a standardization project for examining and creating specifications for mobile communication systems, standardization of non-public networks (NPN) is being promoted.

The 3GPP defines SNPNs (Stand-alone NPNs) that are independent of the 5G public networks and PNI NPNs (Public Network Integrated NPNs) that share all or part of the 5G public networks as non-public networks.

Guidelines for introducing local 5G, December 1st year of Reiwa, Ministry of Internal Affairs and Communications 3GPP TS38.300 V16.3.0 (2020-09)

An object of the present invention is to provide a base station device, a mobile communication system, and a synchronous control method so as to improve frequency utilization efficiency.

The base station apparatus according to the first aspect is included in a non-public cellular network, and includes a communication unit and a control unit. The communication unit uses the first frequency band shared by the base station device and the public service fixed station device and the second frequency band that cannot be used by the public service fixed station device, or the first frequency. The second frequency band is used for wireless communication with the user device without using the band. When the control unit 120 cannot receive the measurement report including the measurement result for the reference base station device using the first frequency band from the user device, the control unit 120 considers that the interference has occurred with respect to the first frequency band. , The communication unit is controlled to use the second frequency band without using the first frequency band.

The mobile communication system according to the second aspect is included in a non-public cellular network, and includes a base station device, a reference base station device, and a user device. The base station device includes a communication unit and a control unit. The communication unit uses the first frequency band shared by the base station device and the public service fixed station device and the second frequency band that cannot be used by the public service fixed station device, or the first frequency. The second frequency band is used for wireless communication with the user device without using the band. When the communication unit cannot receive the measurement report including the measurement result for the reference base station device using the first frequency band from the user device, the communication unit considers that the interference has occurred with respect to the first frequency band. The communication unit is controlled to use the second frequency band without using the first frequency band.

The frequency band control method according to the third aspect is a frequency band control method in a base station apparatus included in a non-public cellular network and having a communication unit and a control unit. In the frequency band control method, the communication unit uses a first frequency band shared by the base station device and the public service fixed station device and a second frequency band that cannot be used by the public service fixed station device. Alternatively, it comprises the step of performing wireless communication with the user apparatus using the second frequency band without using the first frequency band. Further, in the frequency band control method, when the control unit cannot receive the measurement report including the measurement result for the reference base station device using the first frequency band from the user device, the control unit receives the measurement report for the first frequency band. It includes a step of controlling the communication unit to use the second frequency band without using the first frequency band, assuming that interference has occurred.

According to one aspect of the present invention, it is possible to provide a base station device, a mobile communication system, and a frequency band control method so as to improve frequency utilization efficiency.

FIG. 1 is a diagram showing a configuration example of a mobile communication system according to an embodiment. 2 (A) and 2 (B) are diagrams showing examples of frequency bands used in a local 5G system. FIG. 3A is a diagram showing a base station according to an embodiment, and FIG. 3B is a diagram showing a configuration example of a UE according to an embodiment. FIG. 4 is a diagram showing a configuration example of a reference base station according to an embodiment. FIG. 5 is a diagram showing an operation example according to an embodiment. FIG. 6 is a diagram showing an operation example according to an embodiment. FIG. 7 is a diagram showing an operation example according to an embodiment. FIG. 8 is a diagram showing an operation example according to an embodiment. FIG. 9 is a diagram showing an operation example according to an embodiment.

An embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are designated by the same or similar reference numerals.

(Configuration example of mobile communication system)
An example of the configuration of the mobile communication system 10 according to the embodiment will be described. FIG. 1 is a diagram showing a configuration example of a mobile communication system 10 according to an embodiment.

As shown in FIG. 1, the mobile communication system 10 includes a base station device (hereinafter, may be referred to as a “base station”) 100 and a UE (User Equipment) (or a user device, hereinafter, referred to as a “UE”). In some cases) 200, and the reference base station 300 is included.

The base station 100 according to one embodiment may be a gNB (next generation Node B). In this case, the base station 100 functions as a base station device in a 3GPP 5G system.

Further, the base station 100 is a base station device included in the local 5G system. The local 5G system may be a non-public cellular network. The non-public cellular network may be an example of the NPN described above. Further, the local 5G system may be a 5G system built by the owner of the building or land in the building or in the land. The mobile communication system 10 is an example of a non-public cellular network.

The base station 100 in the local 5G system performs wireless communication using a predetermined frequency band.

2 (A) and 2 (B) are diagrams showing an example of a predetermined frequency band.

As shown in FIG. 2A, in the 4.5 GHz band, 4.6 GHz to 4.9 GHz is used in the local 5G system. Of these, 4.6 GHz to 4.8 GHz are shared with public business systems. As a system for public business, there is a system for a national government, a local public body, or a public utility. In the present embodiment, a communication system used for military use as an example of a system for public business will be described. In the 4.5 GHz band, 4.8 GHz to 4.9 GHz is a frequency band used exclusively for the local 5G system.

As shown in FIG. 2B, in the 28 GHz band, 28.2 GHz to 29.1 GHz is a frequency band that can be used in the local 5G system. Of these, the frequency band from 28.2 GHz to 28.3 GHz is dedicated to the local 5G system. In addition, from 28.3 GHz to 29.1 GHz is shared with satellite carriers.

Note that FIGS. 2A and 2B show examples of predetermined frequency bands, and in the present embodiment, the predetermined frequency bands include frequencies other than the 4.5 GHz band and the 28 GHz band. It may be a band.

Returning to FIG. 1, the base station 100 can perform wireless communication with the UE 200 in this way with the frequency band assigned as the local 5G system as a predetermined frequency band.

Further, the base station 100 can wirelessly communicate with the UE 200 by a TDD (Time Division Duplex) system. That is, the base station 100 transmits a radio signal to the UE 200 in the downlink mode, and receives the radio signal transmitted from the UE 200 in the uplink mode. The TDD method is, for example, a method in which communication in the downlink direction and communication in the uplink direction are performed at different timings using the same frequency band.

The UE 200 is, for example, a smartphone, a feature phone, an IoT (Internet of Things) device, a personal computer, a vehicle or a device provided in the vehicle, a flying object or a device provided in the flying object. The UE 200 can receive various services from the base station 100 by wireless communication with the base station 100.

Although FIG. 1 shows an example of one UE 200, there may be a plurality of UEs 200.

The reference base station 300 can transmit a radio signal by using the same frequency band as that used in a public business system. Examples of such a frequency band include the above-mentioned 4.6 GHz to 4.8 GHz. The reference base station 300 can also receive the radio signal transmitted from the UE 200 by using the frequency band. The reference base station 300 transmits and receives radio signals by the TDD method at the same timing as the base station 100.

In FIG. 1, a fixed station device for public business (hereinafter, may be referred to as a “fixed station for public business”) 400 is provided. The public service fixed station 400 is included in the public service system. The public service fixed station 400 transmits a radio signal using the frequency band assigned to the public service system, in the present embodiment, the frequency band from 4.6 GHz to 4.8 GHz. At this time, the fixed station 400 for public business transmits a radio signal irregularly using a very large transmission power.

(Configuration example of base station 100)
FIG. 3A is a diagram showing a configuration example of the base station 100.

As shown in FIG. 3, the base station 100 includes a backhaul communication unit 110, a control unit 120, and a communication unit 130.

The backhaul communication unit 110 is connected to an external network. The backhaul communication unit 110 receives the packet transmitted from the external network under the control of the control unit 120, extracts data and the like from the received packet, and transmits the data to the control unit 120. Further, the backhaul communication unit 110 converts the data output from the control unit 120 into a packet under the control of the control unit 120, and transmits the converted packet to the external network.

The control unit 120 controls the backhaul communication unit 110 and the communication unit 130. The control unit 120 executes each process or each function in the base station 100 described later. Therefore, the control unit 120 includes a processor such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor) and a memory. Each process or each function described later may be executed by the cooperative operation of the processor and the memory.

Under the control of the control unit 120, the communication unit 130 performs modulation processing, frequency conversion processing, and the like on the data or control signal output from the control unit 120, and converts (up-converts) the data or the control signal into a wireless signal. The communication unit 130 transmits the converted radio signal to the UE 200. Further, the communication unit 130 receives the radio signal transmitted from the UE 200, performs frequency conversion processing, demodulation processing, and the like on the received radio signal, and converts (down-converts) it into data, a control signal, or the like. The communication unit 130 outputs the converted data and the like to the control unit 120.

Under the control of the control unit 120, the communication unit 130 transmits a radio signal to the UE 200 in the downlink mode, and receives the radio signal transmitted from the UE 200 in the uplink mode. The communication unit 130 can transmit and receive radio signals by using the frequency band assigned for the local 5G system.

(Configuration example of UE200)
FIG. 3B is a diagram showing a configuration example of the UE 200.

As shown in FIG. 3B, the UE 200 includes a control unit 210 and a communication unit 220.

The control unit 210 controls the communication unit 220. The control unit 210 executes each process or each function in the UE 200 described later. Therefore, the control unit 210 may also include a processor such as a CPU and a memory, and can execute each process or each function in the UE 200 by the cooperative operation of the processor and the memory.

The communication unit 220 receives the radio signal transmitted from the base station 100 under the control of the control unit 210, and performs frequency conversion processing, demodulation processing, and the like on the received radio signal to data or control the radio signal. Convert (down-convert) to a signal or the like. The communication unit 220 outputs the converted data, control signals, and the like to the control unit 210.

Further, the communication unit 220 performs modulation processing, frequency conversion processing, and the like on the data or control signal output from the communication unit 220 under the control of the control unit 210 to obtain the data or control signal as a wireless signal. Convert (up-convert) to. The communication unit 220 transmits the converted radio signal to the base station 100.

(Configuration example of reference base station 300)
FIG. 4 is a diagram showing a configuration example of the reference base station 300.

The reference base station 300 includes a backhaul communication unit 310, a control unit 320, and a communication unit 330.

The backhaul communication unit 310 is connected to an external network, receives a packet transmitted from the external network under the control of the control unit 320, and extracts data or the like from the received packet. The backhaul communication unit 310 outputs the extracted data and the like to the control unit 320.

Further, the backhaul communication unit 310 converts the data output from the control unit 320 into a packet under the control of the control unit 320, and transmits the converted packet to the external network.

The control unit 320 controls the backhaul communication unit 310 and the communication unit 330. The control unit 320 executes each process or each function described later in the reference base station 300. Therefore, the control unit 320 may also include a processor such as a CPU and a memory, and can execute each process or each function in the reference base station 300 by the cooperative operation of the processor and the memory.

Under the control of the control unit 320, the communication unit 330 performs modulation processing and frequency conversion processing on the data or control signal output from the control unit 320, and converts the data or control signal into a wireless signal (up). Convert). The communication unit 330 transmits the converted radio signal to the UE 200.

Further, the communication unit 330 receives the radio signal transmitted from the UE 200 under the control of the control unit 320, performs frequency conversion processing and demodulation processing on the received radio signal, and converts the received radio signal into data or a control signal. (Down-convert). The communication unit 330 outputs the converted data, control signals, and the like to the control unit 320.

(Operation example)
FIG. 5 is a diagram showing an operation example when a radio signal is transmitted from the public service fixed station 400 when the reference base station 300 does not exist.

In the example of FIG. 5, the base station 100 represents an example in which wireless communication is performed with the UE 200 using the frequency band of 4.6 GHz to 4.9 GHz. In this case, consider the case where the fixed station 400 for public business also transmits a radio signal using the frequency band of 4.6 GHz to 4.8 GHz.

The UE 200 can receive both a radio signal from the base station 100 and a radio signal from the public service fixed station 400 in the frequency band of 4.6 GHz to 4.8 GHz.

However, the UE 200 does not have the identification information of the public service fixed station 400. When the UE 200 measures the radio quality for each base station and reports the measurement result, the UE 200 does not have the identification information for the public fixed station 400, and therefore reports the measurement result for the public fixed station 400. Can't. The UE 200 cannot report the measurement result from 4.6 GHz to 4.8 GHz, and reports the measurement result from 4.8 GHz to 4.9 GHz to the base station 100 using the identification information of the base station 100. It is possible.

In this case, the base station 100 cannot grasp the reason why the measurement result could not be obtained from 4.6 GHz to 4.8 GHz. Moreover, even if the base station 100 transmits a radio signal using the frequency band of 4.6 GHz to 4.8 GHz in the downlink mode, the UE 200 uses the same frequency band from the fixed station 400 for public business. Interference occurs due to the generated radio signal.

In such a situation, it cannot be said that the frequency is effectively used in the frequency band of 4.6 GHz to 4.9 GHz.

Therefore, in the present embodiment, the base station 100 included in the non-public cellular network, and the base station 100 including the communication unit 130 and the control unit 120, performs the following control.

That is, the communication unit 130 cannot use the first frequency band (for example, the frequency band of 4.6 GHz to 4.8 GHz) shared by the base station 100 and the public service fixed station 400 and the public service fixed station 400. The second frequency band (for example, the frequency band of 4.8 GHz to 4.9 GHz) is used for wireless communication with the UE 200.

Further, when the control unit 120 cannot receive the measurement report including the measurement result for the reference base station 300 using the first frequency band from the UE 200, the control unit 120 considers that the interference has occurred with respect to the first frequency band. Therefore, the communication unit 130 is controlled so as to use the second frequency band without using the first frequency band.

On the other hand, when the UE 200 has acquired the identification information of the reference base station 300, the UE 200 can transmit the measurement result of the radio quality for the reference base station 300 to the base station 100 by using this identification information. Since the reference base station 300 uses the same frequency band as the public service fixed station 400 (for example, the first frequency band), when the public service fixed station 400 starts using the frequency band, the radio is used. Since the transmission power of the signal is very large, the UE 200 cannot obtain the measurement result for the reference base station 300. When the base station 100 cannot receive the measurement result for the reference base station 300 from the UE 200, the base station 100 considers that interference has occurred in the first frequency band. Then, the base station 100 uses the second frequency band without using the first frequency band to perform wireless communication with the UE 200.

Therefore, since the frequency band used by the base station 100 is the second frequency band that can be used, the frequency utilization efficiency can be improved as compared with the case where the first frequency band that cannot be used is included. It will be possible.

In the following, an operation example will be described with reference to the drawings. First, an operation example when a wireless signal is not transmitted from the fixed station 400 for public business will be described. Next, an operation example when a wireless signal is transmitted from the fixed station 400 for public business will be described. In the example shown below, both the reference base station 300 and the public service fixed station 400 shall transmit radio signals using the frequency band of 4.6 GHz to 4.8 GHz.

(When the wireless signal is not transmitted from the fixed station 400 for public business)
FIG. 6 is a diagram showing an operation example when a radio signal is not transmitted from the fixed station 400 for public business.

The base station 100 transmits the measurement setting information to the UE 200 before the operation shown in FIG. 6 is performed. The measurement setting information includes information regarding measurement in the frequency band of 4.6 GHz to 4.8 GHz and / or measurement for the reference base station 300.

Specifically, the measurement setting information includes, for example, a frequency band of 4.6 GHzk to 4.9 GHz band as a measurement target. Further, the measurement setting information may include a frequency band in the range of 4.6 GHzk to 4.8 GH as a measurement target. Further, the measurement setting information includes the base station 100 and / or the reference base station 300 as measurement targets. Further, the measurement setting information may include an instruction to measure received power (RSRP: Received Signal Received Power) or received quality (RSRQ: Reference Signal Received Quality) as a measurement method. Further, the measurement setting information includes, for example, an instruction indicating that the measurement is performed periodically. Further, the measurement setting information includes an instruction to send a measurement report including the measurement result by using, for example, the Measurement Menr Report.

The base station 100 may transmit the measurement setting information to the UE 200 by using the “Measurement Connection”. In this case, the base station 100 includes the "Measurement Connection" in the "RRC Connection Reconnection" message and transmits the message to the UE 200.

Further, the base station 100 notifies the notification information before the operation shown in FIG. 6 is performed. The broadcast information includes identification information (ID: Identification) of the reference base station 300. The UE 200 receives the broadcast information and acquires the identification information of the reference base station 300. The identification information of the base station 100 may be acquired when the UE 200 connects to the base station 100, or may be included in the broadcast information.

In the example of FIG. 6, in the downlink mode, the base station 100 has a frequency band of 4.6 GHz to 4.9 GHz (or any frequency included in the frequency band. In the following, the two are not distinguished from each other. The radio signal is transmitted by using). The reference base station 300 also transmits a radio signal using the frequency band of 4.6 GHz to 4.8 GHz in the downlink mode.

The UE 200 acquires the measurement result for the base station 100 based on the radio signal received from the base station 100 according to the measurement setting information. Further, the UE 200 acquires the measurement result for the reference base station 300 based on the radio signal received from the reference base station 300 according to the measurement setting information. The UE 200 may acquire the measurement result by using the reference signal for measurement among the radio signals transmitted from the base station 100 and the reference base station 300, for example. The UE 200 transmits a measurement report (or Measurement Report) including the two acquired measurement results to the base station 100 in the uplink mode.

By confirming that the identification information of the reference base station 300 is included in the measurement report, the base station 100 can grasp that the public business fixed station 400 is not used. Then, the base station 100 can decide to use (or continue to use) 4.6 GHz to 4.8 GHz shared by the reference base station 300 and the public service fixed station 400.

(When a wireless signal is transmitted from the fixed station 400 for public business)
FIG. 7 is a diagram showing an operation example in which the public service fixed station 400 transmits a wireless signal from 4.6 GHz to 4.8 GHz after the operation of FIG. 6.

In the downlink mode, the UE 200 receives the radio signal transmitted from the base station 100, the radio signal transmitted from the reference base station 300, and the radio signal transmitted from the public service fixed station 400. The UE 200 acquires the measurement result according to the measurement setting information. At this time, the fixed station 400 for public business transmits a radio signal using a frequency band of 4.6 GHz to 4.8 GHz with very strong power. Therefore, the UE 200 cannot obtain the measurement result for the reference base station 300 in the frequency band. However, the UE 200 can obtain measurement results for the frequency band from the public service fixed station 400 to the base station 100 to 4.8 GHz to 4.9 GHz. Therefore, the UE 200 transmits a measurement report including the measurement result for the base station 100 in the frequency band to the base station 100.

The base station 100 can confirm that the interference has occurred in the frequency band of 4.6 GHz to 4.8 GHz by confirming that the measurement report does not have the identification information of the reference base station 300. Alternatively, since the UE 200 periodically transmits the measurement report, the base station 100 confirms that the measurement report does not have the identification information of the reference base station 300 for a certain period of time, so that the frequency is changed from 4.6 GHz to 4.8 GHz. It is also possible to confirm that interference has occurred in the frequency band.

That is, for example, as shown in FIG. 6, when the public service fixed station 400 is not used (in the time zone), the base station 100 can obtain the measurement result for the reference base station 300 (regularly) from the UE 200. can. In such a situation, when the base station 100 cannot obtain the measurement result for the reference base station 300 from the UE 200, for example, as shown in FIG. 7, the public service fixed station 400 starts to use the base station 100. It is determined that interference has occurred at 4.6 GHz to 4.8 GHz.

In the example of FIG. 7, the number of UEs 200 in the base station 100 is one, but there may be a plurality of UEs 200. In this case, the base station 100 may confirm that the interference has occurred in the frequency band by confirming that there is no identification information in the measurement reports from all the UEs 200 in the base station 100. Alternatively, the base station 100 may know that interference has occurred in the frequency band by confirming that the measurement reports from all UEs 200 do not have the identification information of the reference base station 300 for a certain period of time. Alternatively, the base station 100 confirms that there is no identification information in the measurement report from the number of UEs 200 exceeding the threshold value among all the UEs 200 located in the base station 100, or from the number of UEs 200 exceeding the threshold value for a certain period of time. It may be confirmed that the interference has occurred in the frequency band by confirming that there is no identification information in the measurement report of.

In addition, instead of "confirming that there is no identification information of the reference base station 300", the base station 100 "confirms that the measurement result for the reference base station 300 is not included in the measurement report". May be good.

Then, when the base station 100 confirms that the interference has occurred in the frequency band of 4.6 GHz to 4.8 GHz, the frequency band used is changed from the frequency band of 4.6 GHz to 4.9 GHz to 4.6 GHz to 4.6 GHz. The frequency band used is switched so as to use the frequency band from 4.8 GHz to 4.9 GHz without using the frequency band of 8 GHz.

FIG. 8 is a diagram showing an operation example when the frequency band used is switched from the frequency band of 4.8 GHz to the frequency band of 4.9 GHz. In this case, the frequency band (4.8 GHz to 4.9 GHz) different from the frequency band (4.6 GHz to 4.8 GHz) used in the public service fixed station 400 is used between the base station 100 and the UE 200. Wireless communication is performed. Therefore, the base station 100 can stably provide the service to the UE 200.

(Operation example)
FIG. 9 is a diagram showing an operation example according to the present embodiment. Each process or each operation may be performed by, for example, the control unit 120 of the base station 100.

When the base station 100 starts the process in step S10, the base station 100 periodically acquires radio information from the UE 200 in step S11.

In step S12, the base station 100 determines whether or not interference occurs at 4.6 GHz to 4.8 GHz. As described above, the base station 100 determines that interference has occurred if the measurement report does not have the identification information of the reference base station 300, and if the measurement report contains the identification information of the reference base station 300, no interference has occurred. May be determined. Alternatively, the base station 100 determines that the interference has occurred when the measurement report without the identification information of the reference base station 300 is not received for a certain period of time, and determines that the interference has not occurred otherwise. May be good.

In step S12, when the base station 100 determines that interference has occurred from 4.6 GHz to 4.8 GHz (YES in step S12), in step S13, the base station 100 sets its own frequency from 4.6 GHz. It is determined whether or not 4.8 GHz is included. In the example of FIG. 7, since the base station 100 uses from 4.6 GHz to 4.9 GHz, it is determined that the base station 100 includes 4.6 GHz to 4.8 GHz (YES in step S13).

Returning to FIG. 9, when the base station 100 determines in step S13 that the own station frequency includes 4.6 GHz to 4.8 GHz (YES in step S13), in step S14, the base station 100 has its own station frequency. Is changed from 4.8 GHz to 4.9 GHz. In the example of FIG. 7, the base station 100 controls the communication unit 130 to use the frequency band of 4.8 GHz to 4.9 GHz without using the frequency band of 4.6 GHz to 4.8 GHz. Change (or switch) the own station frequency from 4.8 GHz to 4.9 GHz.

In step S15, the base station 100 determines whether or not the end trigger is satisfied. As the end trigger, for example, there is an instruction from the host station to the base station 100 to end a series of processes shown in FIG. When the base station 100 receives such an instruction, it determines that the end trigger is satisfied (YES in step S15), and ends a series of processes in step S16.

On the other hand, when the base station 100 determines in step S15 that the end trigger is not satisfied (NO in step S15), the base station 100 proceeds to step S11 and repeats the above-mentioned process.

On the other hand, when it is determined in step S13 that the base station 100 does not include 4.6 GHz to 4.8 GHz as its own station frequency (NO in step S13), the processing after step S15 is performed. For example, as shown in FIG. 8, even if interference occurs from 4.6 GHz to 4.8 GHz, the frequency is particularly changed when the base station 100 and the public service fixed station 400 use different frequency bands. The processing after step S15 will be performed without any problem.

On the other hand, when the base station 100 determines in step S12 that interference does not occur from 4.6 GHz to 4.8 GHz (NO in step S12), the base station 100 sets the frequency as its own station in step S17. It is determined whether or not the product contains 4.6 GHz to 4.8 GHz. In the example of FIG. 6, since the fixed station 400 for public service does not transmit a radio signal, interference does not occur in the frequency band from 4.6 GHz to 4.8 GHz. In this case, the base station 100 determines whether or not the own station frequency includes 4.6 GHz to 4.8 GHz.

In step S17, when the base station 100 determines that the own station frequency includes 4.6 GHz to 4.8 GHz (YES in step S17), the process proceeds to step S15 and the above-mentioned process is repeated. In the example of FIG. 6, when the base station 100 uses 4.6 GHz to 4.9 GHz as its own frequency, interference does not occur at 4.6 GHz to 4.8 GHz, so that the frequency is particularly high. The process proceeds to step S15 without making any changes.

On the other hand, when it is determined in step S17 that the base station 100 does not include the own station frequency of 4.6 GHz to 4.8 GHz (NO in step S17), in step S18, the base station 100 sets the own station frequency to 4. Change from 6.6GHz to 4.9GHz. For example, as shown in FIG. 7, when the frequency of the own station is changed from 4.8 GHz to 4.9 GHz and then the radio signal is not transmitted from the fixed station 400 for public service, the state shown in FIG. 6 is obtained. .. In this case, since the base station 100 no longer causes interference from 4.6 GHz to 4.8 GHz, the base station 100 returns its own frequency from the original 4.6 GHz to 4.9 GHz.

In step S18, the base station 100 changes its own station frequency to 4.6 GHz-4.9 GHz, shifts to step S15, and repeats the above-mentioned process.

As described above, in the present embodiment, when the base station 100 detects that the interference has occurred from 4.6 GHz used by the fixed station 400 for public business to 4.8 GHz, the base station 100 sets its own frequency to 4.6 GHz. To 4.9 GHz frequency band is changed from 4.8 GHz to 4.9 GHz frequency band (step S14 in FIG. 9).

As a result, the frequency used by the base station 100 uses a frequency band that does not include interference (4.8 GHz to 4.9 GHz), and therefore a frequency band that includes interference (4.6 GHz to 4.9 GHz) is used. It is possible to improve the frequency utilization efficiency as compared with the case where the frequency is used.

Further, after changing the frequency used by the base station 100 from 4.8 GHz to 4.9 GHz and then eliminating interference in the frequency band from 4.6 GHz to 4.8 GHz, the base station 100 changes the used frequency band. Returning to the frequency band from 4.6 GHz to 4.9 GHz (step S18 in FIG. 9). As a result, interference by the fixed station 400 for public business is eliminated in the entire band from 4.6 GHz to 4.9 GHz, which is the frequency band used. Therefore, in the base station 100, a wide band frequency band can be used as compared with the case where 4.8 GHz to 4.9 GHz is used. Therefore, it can be said that the base station 100 can efficiently use the usable frequency band, and thus can improve the frequency utilization efficiency.

Further, the base station 100 uses the Measurement Report used in the cellular wireless communication system to cause the UE 200 to transmit a measurement report. Therefore, since the base station 100 does not separately provide an interference detection unit, it is possible to suppress an increase in the cost of the base station 100.

(Other embodiments)
In the above-described embodiment, an example in which the frequency band used by the base station 100 is the 4.5 GHz band has been described. The frequency band used by the base station 100 may be a 28 GHz band. In this case, when the base station 100 uses 28.2 GHz to 29.1 GHz, it determines that interference has occurred in the frequency band from 28.3 GHz to 29.1 GHz, and determines that the frequency band used is from 28.2 GHz. You may switch to the frequency band of 28.3 GHz. Then, when the interference disappears in the frequency band from 28.3 GHz to 29.1 GHz, the base station 100 returns the used frequency band to the frequency band from 28.2 GHz to 29.1 GHz.

Further, in the above-described embodiment, reception power (RSRP) or reception quality (RSRQ) has been described as an example as a measurement method. For example, the measuring method may be received signal strength (RSSI: Received Signal Strength Indicator), SIR (Signal to Interference Ratio), SINR (Signal to Interference plus Noise Ratio), or the like.

Although the embodiments have been described in detail with reference to the drawings, the specific configuration is not limited to the above, and various design changes and the like can be made within a range that does not deviate from the gist. Further, the above-mentioned examples can be combined within a consistent range.

10: Mobile communication system 100: Base station 110: Backhaul communication unit 120: Control unit 130: Communication unit 200: UE
210: Control unit 220: Communication unit 300: Reference base station 310: Backhaul communication unit 320: Control unit 330: Communication unit 400: Public business fixed station

Claims (7)

A base station device included in a non-public cellular network
Using the first frequency band shared by the base station device and the public service fixed station device and the second frequency band not available to the public service fixed station device, or using the first frequency band. A communication unit that wirelessly communicates with a user device using the second frequency band without using it.
When the measurement report including the measurement result for the reference base station device using the first frequency band cannot be received from the user device, it is considered that the interference has occurred with respect to the first frequency band, and the first A base station apparatus including a control unit that controls the communication unit so as to use the second frequency band without using the frequency band 1. The base station apparatus according to claim 1, wherein the communication unit transmits measurement setting information for setting measurements for the first and second frequency bands and the reference base station to the user apparatus. The base station device according to claim 1, wherein the control unit controls the communication unit to perform wireless communication with the user device using the first and second frequency bands when the measurement report can be received. .. When the control unit receives the measurement report after controlling the communication unit so as to use the second frequency band without using the first frequency band, the first and second frequencies The base station apparatus according to claim 1, wherein the communication unit is controlled so as to perform wireless communication with the user apparatus using a band. The base station apparatus according to claim 1, wherein the first frequency band is a frequency band of 4.6 GHz to 4.8 GHz, and the second frequency band is a frequency band of 4.8 GHz to 4.9 GHz. A mobile communication system included in a non-public cellular network.
Base station equipment and
Reference base station equipment and
Equipped with user equipment
The base station device is
Using the first frequency band shared by the base station device and the public service fixed station device and the second frequency band not available to the public service fixed station device, or using the first frequency band. A communication unit that wirelessly communicates with a user device using the second frequency band without using it.
When the measurement report including the measurement result for the reference base station apparatus using the first frequency band cannot be received from the user apparatus, it is considered that the interference has occurred with respect to the first frequency band, and the first A mobile communication system including a control unit that controls the communication unit so as to use the second frequency band without using the frequency band 1. It is a frequency band control method in a base station apparatus included in a non-public cellular network and having a communication unit and a control unit.
The communication unit uses the first frequency band shared by the base station device and the public service fixed station device and the second frequency band not available to the public service fixed station device, or the first. A step of performing wireless communication with a user device using the second frequency band without using the frequency band of 1.
When the control unit cannot receive the measurement report including the measurement result for the reference base station apparatus using the first frequency band from the user apparatus, it is said that the interference has occurred with respect to the first frequency band. A frequency band control method comprising a step of controlling the communication unit to use the second frequency band without using the first frequency band.

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