JP7481981B2 - Base station device and bandwidth control method - Google Patents

Description

The present invention relates to a base station device and a bandwidth control method.

Recently, 5th generation mobile communication systems that can be used by various entities according to regional or individual needs have been attracting attention. Such mobile communication systems are sometimes called local 5G (5th Generation), for example.

Local 5G allows various entities, such as local companies and local governments, to set up their own spot networks within their own buildings or on their premises, separate from the nationwide 5G systems provided by mobile carriers. For this reason, local 5G is expected to be used to meet a variety of needs closely tied to local communities.

On the other hand, the 3GPP (3rd Generation Partnership Project), a standardization project that studies and creates specifications for mobile communication systems, is working on standardization of non-public networks (NPN).

3GPP specifies two types of non-public networks: SNPN (Stand-alone NPN), which is independent of the 5G public network, and PNI NPN (Public Network Integrated NPN), which shares all or part of the 5G public network.

On the other hand, in mobile communication systems, the TDD (Time Division Duplex) method has been used in some cases. The TDD method is a method in which, for example, downlink communication (the communication link direction from the base station to the terminal) and uplink communication (the communication link direction from the terminal to the base station) are performed at different times using the same frequency band.

Guidelines for the introduction of local 5G, December 2019, Ministry of Internal Affairs and Communications 3GPP TS38.300 V16.2.0 (2020-07)

However, in a TDD system, if there is a timing discrepancy between base stations, the uplink time and the downlink time may occur at the same timing. In such cases, interference occurs at the base station. The interference makes it impossible for the base station to continue to provide stable service to terminals.

The present invention aims to provide a base station device and a bandwidth control method that can continuously provide stable services.

A base station device according to a first aspect is included in a non-public cellular network and performs wireless communication in a TDD system. The base station device includes first and second wireless units, a control unit, and a receiving unit. The first and second wireless units perform wireless communication with a user device using a predetermined frequency band. The control unit controls the first and second wireless units. The receiving unit receives a synchronization signal. When the receiving unit is unable to normally receive the synchronization signal, the control unit assigns a first frequency band of the predetermined frequency bands to the first wireless unit and a second frequency band of the predetermined frequency bands to the second wireless unit as frequency bands for performing wireless communication.

The bandwidth control method according to the second aspect is a bandwidth control method in a base station device that is included in a non-public cellular network and performs wireless communication in a TDD system, the base station device including a first and a second wireless unit that perform wireless communication with a user device using a predetermined frequency band, a control unit that controls the first and second wireless units, and a receiving unit that receives a synchronization signal. The bandwidth control method includes a step of determining in the receiving unit whether or not the synchronization signal has been successfully received. The bandwidth control method also includes a step of, when the receiving unit has not successfully received the synchronization signal, assigning in the control unit a first frequency band of the predetermined frequency band to the first wireless unit and a second frequency band of the predetermined frequency band to the second wireless unit as frequency bands for performing wireless communication.

According to one aspect of the present invention, it is possible to provide a base station device and a bandwidth control method that enable stable and continuous service to be provided.

FIG. 1 is a diagram illustrating a configuration of a communication system according to an embodiment. A diagram showing an example of the division of functions between a CU, DU, and RU according to one embodiment. A diagram showing the configuration of CU and DU in one embodiment. FIG. 2 is a diagram showing the configuration of an RU according to an embodiment; A diagram showing an example of a protocol stack for O-RAN fronthaul according to one embodiment. A figure showing an example of a message in O-RAN fronthaul according to one embodiment. FIG. 11 is a diagram illustrating an example of an operation of changing a bandwidth according to an embodiment. FIG. 13 illustrates an example of an operation of bandwidth allocation according to an embodiment. FIG. 1 is a diagram illustrating an example of operation according to a TDD method according to an embodiment.

The embodiments will be described with reference to the drawings. In the description of the drawings, the same or similar parts are given the same or similar reference numerals.

(Example of a communication system configuration)
First, a configuration example of a communication system 10 according to an embodiment will be described. Fig. 1 is a diagram showing a configuration example of a communication system 10 according to an embodiment.

As shown in FIG. 1, the communication system 10 includes a gNB (next generation Node B) 100 and user devices 200-1 to 200-3.

The gNB 100 according to one embodiment is an example of a base station device. The gNB 100 functions as a base station device in a 3GPP 5G system. The gNB 100 performs wireless communication with user equipment (UE) 200-1 to 200-3 and provides various services to the user equipment 200-1 to 200-3.

The gNB 100 is a base station device included in a 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. Alternatively, the local 5G system may be a 5G system built by the owner of a building or land, etc., within a building or land.

The gNB 100 in the local 5G system performs wireless communication using a predetermined frequency band. An example of the predetermined frequency band is the 4.5 GHz band. The gNB 100 in this embodiment may use a frequency band other than the 4.5 GHz band as long as it is a predetermined frequency band used by the base station device of the local 5G system.

User devices 200-1 to 200-3 are, for example, smartphones, feature phones, IoT (Internet of Things) devices, personal computers, etc. In the example of FIG. 1, three user devices 200-1 to 200-3 are shown, but there may be one or two, or four or more.

Note that FIG. 1 shows an artificial satellite 300. The gNB 100 is capable of receiving a GNSS (Global Navigation Satellite System) signal transmitted from the artificial satellite 300.

Note that GPS (Global Positioning System) is an example of GNSS. In the following, GPS will be used as an example. gNB100 will be able to receive GPS signals.

(Example of configuration of gNB100)
As shown in FIG. 1, the gNB 100 has a CU (Centralized Unit) 110, a DU (Distributed Unit) 120, and multiple RUs (Radio Units) 130-1 and 130-2.

CU110 may be referred to as an aggregation unit, for example. CU110 is connected to DU120 and controls DU120.

The CU 110 may be connected to an external network 400 to transmit and receive data between the CU 110 and the external network 400.

DU120 may be referred to as a distributed unit, for example. DU120 is connected to CU110 and also to multiple RUs130-1 and 130-2. DU120 controls multiple RUs130-1 and 130-2.

Each of the RUs 130-1 and 130-2 may be referred to as a wireless unit, for example. Each of the RUs 130-1 and 130-2 is controlled by the DU 120 and performs wireless communication using the TDD method.

That is, in each RU 130-1, 130-2, a first communication in the downlink direction from the gNB 100 to the user equipment 200-1 to 200-3 and a second communication in the uplink direction from the user equipment 200-1 to 200-3 to the gNB 100 are performed at different timings using the same frequency band. Furthermore, in each RU 130-1, 130-2, the first communication and the second communication are performed in synchronization with each other based on the GPS signal.

Figures 9(A) and 9(B) are diagrams showing examples of operation in a TDD system. Of these, Figure 9(A) shows an example of operation when each of RUs 130-1 and 130-2 is synchronized with a GPS signal.

As shown in FIG. 9(A), RU130-1 and RU130-2 are performing D (downlink direction), S (special frame), and U (uplink direction) at the same time. "D" indicates a subframe in which communication in the downlink direction is performed, and "U" indicates a subframe in which communication in the uplink direction is performed. "S" is a special subframe, and includes an uplink period, a downlink period, and a guard section.

Also, in FIG. 9(A), "GPS (Global Positioning System) standard" is shown. The gNB 100 performs timing synchronization of each RU 130-1, 130-2 based on the received GPS signal. In the example of FIG. 9(A), timing synchronization is performed at "GPS standard" timing. Also, in the example of FIG. 9(A), each RU 130-1, 130-2 is set to "D" at "GPS standard" timing.

In the example of Figure 9 (A), for example, at timing "D", a wireless signal is transmitted from RU 130-1. That wireless signal reaches RU 130-2. However, RU 130-2 is transmitting a wireless signal at the same timing as RU 130-1. Therefore, RU 130-2 does not receive the wireless signal transmitted from RU 130-1. Therefore, no interference occurs.

On the other hand, Figure 9 (B) shows an example of operation when interference occurs. As shown in Figure 9 (B), in the "GPS standard," the GPS signal cannot be received normally, and the timing is not synchronized between RUs 130-1 and 130-2.

In this case, the timings of "D", "S", and "U" are different between RU 130-1 and RU 130-2. For example, as shown by the arrows in FIG. 9(A), RU 130-1 is at timing "D" and RU 130-2 is at timing "U". In this case, RU 130-1 transmits a radio signal to user equipment 200-1 at timing "D", and the radio signal reaches RU 130-2. RU 130-2 receives the radio signal transmitted from RU 130-1 because of timing "U". Therefore, interference occurs in RU 130-2. Similarly, interference also occurs in RU 130-1.

If gNB100 stops transmitting radio waves in response to such interference, it will not be able to provide continuous services to user equipment 200-1 to 200-3. Furthermore, even if such interference occurs, if gNB100 continues providing services, user equipment 200-1 to 200-3 will not be able to receive services in some cases, or will not be able to receive stable services.

Therefore, in the gNB100 of this embodiment, when a GPS signal cannot be received normally, the first frequency band of the frequency bands used by RU130-1 and RU130-2 is assigned to RU130-1, and the second frequency band is assigned to RU130-2.

As shown by the arrows in Figure 9 (B), even if RU 130-1 is at "D" and RU 130-2 is at "U", interference does not occur because different frequency bands are used between RU 130-1 and 130-2. Therefore, gNB 100 can continue to provide stable services to user equipment 200-1 and 200-2.

Returning to FIG. 1, this embodiment will be described assuming that DU 120 receives GPS signals from satellite 300.

In the following, unless otherwise specified, RUs 130-1 and 130-2 may be referred to as RU 130, and user devices 200-1 to 200-3 may be referred to as user devices 200.

(Functional separation of CU110, DU120, and RU130)
In the gNB100 in this embodiment, the case where the O-RAN (Open Radio Access Network) fronthaul specification is adopted between the DU120 and the RU130 is described in detail. Note that between the DU120 and the RU130, other communication protocols can be used instead of the O-RAN fronthaul specification, and the use of the O-RAN fronthaul specification is not limited. Therefore, the example of the O-RAN fronthaul specification is only one example. O-RAN is a specification formulated by the O-RAN Alliance, which includes multiple telecommunications carriers. In the O-RAN, Split Option 7-2x is adopted for functional separation of the CU110, the DU120, and the RU130.

Figure 2 shows an example of functional separation of CU110, DU120, and RU130 by Split Option 7-2x. As shown in Figure 2, CU110 is capable of executing the functions of each layer of RRC (Radio Resource Control), SDAP (Service Data Adaptation Protocol), and PDCP (Packet Data Convergence Protocol). In addition, DU120 is capable of executing the functions of each layer of RLC (Radio Link Control), MAC (Media Access Control), and PHY-High (Physical-High) (part of PHY). In addition, RU130 is capable of executing the functions of each layer of PHY-Low (part of PHY) and RF (Radio Frequency).

One of the features of O-RAN is that part of the PHY layer is located in RU130. This makes it possible to reduce the burden on DU120, for example.

As shown in FIG. 2, in the PHY-HIgh layer, in the downlink direction of the user plane, error correction coding, scrambling, modulation, layer mapping, and other processes are performed on data from the MAC layer. Through these processes, the PHY-HIgh layer generates an IQ (In-phase and Quadrature) sample sequence of an OFDM (Orthogonal Frequency Division) signal in the frequency domain. DU120 transmits this IQ sample sequence to RU130.

RU 130 receives the IQ sample sequence of the OFDM signal. In the PHY-Low layer, IFFT (Inverse Fast Fourier Transfer) processing and analog conversion processing are performed. In the PHY-Low layer, the IQ sample sequence of the OFDM signal is converted into a time-domain analog signal. Then, RU 130 converts the analog signal into a radio signal.

As shown in FIG. 2, in the uplink direction of the user plane, the process is basically the reverse of that in the downlink direction in the PHY-Low layer and the PHY-High layer. RU 130 transmits an IQ sample sequence of the frequency domain OFDM signal to DU 120.

As described above, the O-RAN fronthaul specification may be adopted between DU120 and RU130. Figure 5 shows a protocol stack of such a specification. Figure 6(A) shows an example of the configuration of an eCPRI message in the U-Plane (User-Plane), and Figure 6(B) shows an example of the configuration of an eCPRI (enhanced Common Public Radio Interface) message in the C-Plane (Control-Plane).

As shown in FIG. 6A, eCPRI messages of the U-Plane are transmitted and received between the DU 120 and the RUs 130-1 and 130-2. IQ sample sequences and the like are inserted into the payload area of these eCPRI messages.

As shown in FIG. 6B, eCPRI messages of the C-Plane are transmitted and received between DU 120 and RUs 130-1 and 130-2. Various control information and the like are inserted into the payload area of this eCPRI message.

(Examples of configurations of CU110, DU120, and RU130)
FIG. 3A shows an example of the configuration of the CU 110, FIG. 3B shows an example of the configuration of the DU 120, and FIG.

As shown in FIG. 3(A), the CU 110 has an interface unit 111 and a control unit 112.

The interface unit 111 outputs packet data in a specific format received from the network 400 to the control unit 112, and transmits data and control signals output from the control unit 112 to the DU 120. The interface unit 111 also receives data transmitted from the DU 120, outputs the received data to the control unit 112, and transmits packet data in a specific format output from the control unit 112 to the network 400.

The control unit 112 performs various controls in the CU 110. In addition, the control unit 112 executes the functions of RRC, SDAP, and PDCP, thereby, for example, extracting data from packet data and generating control signals. The control unit 112 outputs the data or control signals to the interface unit 111. In addition, the control unit 112 executes the functions of RRC, SDAP, and PDCP, thereby, for example, converting data into packet data in a specified format. The control unit 112 outputs the packet data to the interface unit 111.

As shown in FIG. 3(B), the DU 120 includes an interface unit 121, a receiving unit 122, and a control unit 123.

The interface unit 121 outputs data or control signals received from the CU 110 to the control unit 123, and transmits eCPRI messages received from the control unit 123 to RUs 130-1 and 130-2. The interface unit 121 also outputs eCPRI messages received from RUs 130-1 and 130-2 to the control unit 123, and transmits data or control signals received from the control unit 123 to the CU 110.

The receiving unit 122 receives the GPS signal transmitted from the artificial satellite 300. The receiving unit 122 outputs the received GPS signal to the control unit 123.

In addition, when the receiving unit 122 is unable to receive the GPS signal normally, it outputs a signal indicating that to the control unit 123.

Here, "when the GPS signal cannot be received normally" includes, for example, when the GPS signal cannot be received, or when the GPS signal can be received but the received power is lower than a threshold value. In addition, "when the GPS signal cannot be received normally" may include, for example, when a GPS signal that should be received periodically cannot be received even once, or when a GPS signal that should be received periodically cannot be received multiple times in succession. Furthermore, "when the GPS signal cannot be received" may be, for example, when a GPS signal cannot be received for a certain period of time, regardless of whether it is periodic, or when a GPS signal cannot be received continuously for a certain period of time.

The control unit 123 executes the functions of RLC, MAC, and PHY-High to generate an eCPR message including the data or control signal output from the interface unit 121. The control unit 123 outputs the eCPR message to the interface unit 121. The control unit 123 also executes these functions to extract the data or control signal from the eCPR message output from the interface unit 121. The control unit 123 outputs the data or control signal to the interface unit 121.

When the control unit 123 receives a GPS signal that has been normally received from the receiving unit 122, the control unit 123 performs synchronization control for each of the RUs 130-1 and 130-2 based on the GPS signal. The synchronization control may use the O-RAN S-Plane (Synchronization-Plane) including PTP (Precision Time Protocol) and the like.

Furthermore, when the control unit 123 receives a signal from the receiving unit 122 indicating that the GPS signal could not be received normally, as described above, it assigns the first frequency band of the specified frequency bands to RU 130-1 and the second frequency band to RU 130-2.

At that time, the control unit 123 determines the bandwidth of the first frequency band and the bandwidth of the second frequency band based on predetermined factors. Details will be described later. The control unit 123 generates a bandwidth change instruction (for example, a C-Plane eCPRI message including the instruction) including information on the determined bandwidth, and outputs it to RUs 130-1 and 130-2 via the interface unit 121.

As shown in FIG. 4, the RU 130 has an interface unit 131, a wireless processing unit 132, and an antenna 133.

The interface unit 131 extracts data or control signals from the eCPRI message transmitted from the DU 120, and outputs the extracted data or control signals to the wireless processing unit 132. In addition, the interface unit 131 generates an eCPRI message including the data or control signal in response to the data or control signal output from the wireless processing unit 132, and outputs the generated eCPRI message to the DU 120.

The wireless processing unit 132 performs PHY-Low layer processing, and further performs conversion processing of data or control signals into wireless signals. The wireless processing unit 132 outputs the wireless signals to the antenna 133. The wireless processing unit 132 also converts the wireless signals received from the antenna 133 into baseband data or control signals, and further performs PHY-Low layer processing, and outputs the processed data or control signals to the interface unit 131.

The antenna 133 transmits the wireless signal output from the wireless processing unit 132 to the user device 200. The antenna 133 also receives the wireless signal transmitted from the user device 200 and outputs the received wireless signal to the wireless processing unit 132.

(Example of operation)
7 is a diagram showing an example of a sequence in this embodiment. This is processing that is mainly performed by the control unit 123 of the DU 120.

When the DU 120 loses the GPS signal in step S10, i.e., the GPS signal cannot be received normally, the DU 120 performs a bandwidth allocation process in step S11. Note that the GPS signal is an example of a synchronization signal for controlling the synchronization of the RU, and the communication system 10 may use a synchronization signal from the network instead of the GPS signal.

Figure 8 is a flowchart showing an example of a bandwidth allocation process.

In step S20, DU120 starts the bandwidth allocation process, and in step S21, it determines the bandwidth for each RU130-1 and 130-2 based on predetermined factors.

As shown in FIG. 8, the predetermined factors include the following four factors.
1) The number of terminals (or user devices 200) accommodated in the RUs 130-1 and 130-2;
2) Traffic information of RUs 130-1 and 130-2;
3) Network slice information from the terminal (or user device 200);
4) Propagation Environment Regarding 1) above, for example, the DU 120 may determine the bandwidth based on the number of user devices 200 accommodated in each of the RUs 130-1 and 130-2 as follows:

In other words, when the number of user devices 200 accommodated by RU 130-1 is greater than the number of user devices 200 accommodated by RU 130-2, DU 120 allocates a frequency bandwidth to RU 130-1 that is greater than the bandwidth allocated to RU 130-2.

DU120 may also determine the bandwidth according to the ratio between the number of user devices 200 accommodated by RU130-1 and the number of user devices 200 accommodated by RU130-2. For example, if the number of the former is N and the latter is M, DU120 allocates the bandwidth to RU130-1 and the bandwidth to RU130-2 in a ratio of "N:M". In this way, by determining the bandwidth according to the number, it is possible to provide continuous service to, for example, user devices 200 accommodated in an RU130 with a large number of devices.

Incidentally, since information on the number of user devices 200 accommodated by each RU 130-1, 130-2 is obtained, for example, by DU 120, DU 120 may determine the bandwidth based on this information.

The above 2) may be, for example, the amount of traffic transmitted and/or received at RU 130-1 and the amount of traffic transmitted and/or received at RU 130-2. For example, DU 120 may determine the bandwidth based on the amount of traffic as follows:

In other words, when the amount of traffic in RU 130-1 is greater than the amount of traffic in RU 130-2, DU 120 allocates a larger bandwidth to RU 130-1 than to RU 130-2 (or vice versa).

Alternatively, when the ratio of the traffic volume in RU 130-1 to the traffic volume in RU 130-2 is "N:M", DU 120 allocates the bandwidth to RU 130-1 and the bandwidth to RU 130-2 to "N:M". By allocating the bandwidth according to the traffic volume in this way, it is possible to provide continuous service to user equipment 200 with a large traffic volume, for example.

The amount of traffic may change over time. Therefore, DU120 may dynamically determine its bandwidth in response to fluctuations in traffic volume.

DU120 may substitute "data" for the above traffic and determine the bandwidth.

In addition, information on the traffic volume of each RU 130-1, 130-2 can be obtained, for example, by DU 120, and DU 120 may determine the bandwidth based on this information.

3) above represents, for example, the type of service provided to the user device 200. For example, the DU 120 may determine the bandwidth based on the service type as follows:

That is, when there is a user device 200 in RU 130-1 that is receiving a large-capacity service such as eMBB (enhanced Mobile Broadband) (or the number of user devices receiving such a service is equal to or greater than a threshold) and there is a user device 200 in RU 130-2 that is receiving a different service, DU 120 allocates a larger bandwidth to RU 130-1 than to RU 130-2. This allows, for example, gNB 100 to provide continuous service to user device 200 that is receiving a large-capacity service.

DU 120 can obtain network slice information transmitted from user device 200 via RUs 130-1 and 130-2, and may determine the bandwidth based on this information.

The above 4) includes the propagation environment between RU130-1, 130-2 and user equipment 200, and the propagation environment between gNB100 and base station equipment of another system. The other system is, for example, a local 5G system built by another person in the same area or the same building.

DU120 may determine the bandwidth for the propagation environment between user device 200 as follows:

That is, when the propagation environment between RU 130-1 and user equipment 200-1 is not better than the propagation environment between RU 130-2 and user equipment 200-2, DU 120 allocates less (or more) bandwidth to RU 130-1 than the bandwidth allocated to RU 130-2. This makes it possible to provide continuous services to user equipment 200 in a good (or bad) propagation environment, for example. Note that whether to allocate less or more may be determined depending on the policy of the user who uses this gNB 100.

The state of the propagation environment can be measured, for example, by each RU 130-1, 130-2 measuring the received power of the signal received from the user device 200. Then, the DU 120 can obtain this information from each RU 130-1, 130-2 and determine the bandwidth based on the propagation environment.

DU120 may also determine the bandwidth for the propagation environment between other systems as follows:

In other words, when RU 130-1 is receiving interference from another system and RU 130-2 is not interfering with the other system, DU 120 allocates a smaller bandwidth to RU 130-1 than to RU 130-2.

The propagation environment can be determined, for example, based on the interference power measured by each RU 130-1, 130-2, to determine whether or not it is experiencing interference from other systems.

The above 1) to 4) may be combined in whole or in part. For example, it is also possible to combine the traffic volume of 2) above with the propagation environment of 4) above. In this case, when the propagation environment of RU130-1 is worse than that of RU130-2 and the traffic volume of RU130-1 is less than that of RU130-2, DU120 allocates a smaller (or larger) bandwidth to RU130-1 than that of RU130-2. As in the above case, whether to allocate a smaller or larger bandwidth may be determined according to the policy of the user who uses the local 5G system.

In addition, once the bandwidth is determined, the above 1) to 4) may be updated depending on changes in the above 1) to 4).

In this way, DU120 determines the bandwidth based on specific factors, making it possible to flexibly allocate bandwidth according to various factors or circumstances for each of RU130-1 and 130-2.

In step S22, DU120 notifies each RU130-1, 130-2 of the determined bandwidth and starts operation with the determined bandwidth.

In step S23, DU120 terminates the bandwidth allocation process.

Returning to FIG. 7, in steps S12 and S13, DU 120 transmits a bandwidth change instruction including information on the determined bandwidth to each of RUs 130-1 and 130-2. Steps S12 and S13 may be performed during the bandwidth allocation process (step S11). The order of steps S12 and S13 may also be reversed.

Other embodiments
In the above-described embodiment, the receiving unit 122 that receives the GNSS signal (or GPS signal) has been described as being in the DU 120. For example, the receiving unit 122 may be in the CU 110. In this case, the control unit 112 of the CU 110 receives a signal from the receiving unit 122 indicating that the GPS signal could not be received normally, and transmits this information to the control unit 123 of the DU 120. This makes it possible to implement the same as the above-described embodiment.

In the above-described embodiment, an example was described in which the bandwidth allocation process (step S11) is performed by the control unit 123 of the DU 120. For example, the bandwidth allocation process may be performed by the control unit 112 of the CU 110. In this case, the receiving unit 122 transmits a signal to the control unit 112 via the interface units 121 and 111 to the effect that the GPS signal could not be received normally. The control unit 112 of the CU 110 then performs the band allocation process (step S11) and transmits a bandwidth change instruction (steps S12 and S13) to each of the RUs 130-1 and 130-2 via the interface unit 111, etc. This makes it possible to implement the process in the same way as in the above-described embodiment.

Furthermore, in the above-mentioned embodiment, an example in which there is one DU 120 has been described. For example, multiple DUs 120 may be provided under one CU 110. In this case, each of the multiple DUs 120 has a receiving unit 122. When one DU 120 detects that it cannot receive GPS signals normally, the information is transmitted to the other DUs 120 via the CU 110. This allows the information to be shared among the DUs 120. After that, each DU 120 may perform a bandwidth allocation process for the RUs 130 under each DU 120.

Although the embodiments have been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes can be made without departing from the spirit of the invention. In addition, the above examples can be combined to the extent that they are not inconsistent.

10: Communication system 100: gNB
110: C.U.
111: Interface unit 112: Control unit 120: DU
121: Interface unit 122: Receiving unit 123: Control unit 130: RU
131: Interface unit 132: Wireless processing unit 133: Antenna 200: User device 300: Satellite 400: Network

Claims (10)

A base station device that is included in a non-public cellular network and performs TDD wireless communication,
First and second radio units that perform the wireless communication with a user device using a predetermined frequency band;
A control unit that controls the first and second wireless units;
A receiving unit that receives a synchronization signal,
When the synchronization signal cannot be normally received by the receiving unit, the control unit assigns a first frequency band among the predetermined frequency bands to the first wireless unit and assigns a second frequency band among the predetermined frequency bands to the second wireless unit as a frequency band for performing the wireless communication. a distributed unit connected to the first and second radio units and controlling the first and second radio units;
an aggregation unit connected to the distribution unit and controlling the distribution unit;
The base station apparatus according to claim 1 , wherein the control unit is provided in the distributed unit or the aggregation unit. The base station device according to claim 1, wherein the control unit determines the first bandwidth of the first frequency band and the second bandwidth of the second frequency band based on a predetermined factor. The base station device according to claim 3, wherein the predetermined factors are all or part of the number of the user devices accommodated in the first and second radio units, the traffic volume of the first and second radio units, the type of service provided to the user devices, and the propagation conditions. The base station device according to claim 4, wherein the control unit allocates the first bandwidth larger than the second bandwidth when the number of first user devices accommodated in the first radio unit is greater than the number of second user devices accommodated in the second radio unit. The base station device according to claim 4, wherein the control unit allocates the first bandwidth larger or smaller than the second bandwidth when the traffic volume of the first wireless unit is larger than the traffic volume of the second wireless unit. The base station device according to claim 4, wherein the control unit allocates the first bandwidth larger than the second bandwidth when the service type provided to the first user device accommodated in the first radio unit among the user devices is a large capacity service and the service type accommodated in the second radio unit is not a large capacity service. The base station device according to claim 4, wherein the control unit allocates the first bandwidth larger or smaller than the second bandwidth when the propagation environment between the first wireless unit and the first user device among the user devices is not better than the propagation environment between the second wireless unit and the second user device. The base station device according to claim 4, wherein the control unit allocates the second bandwidth larger than the first bandwidth when the first wireless unit causes interference with another system and the second wireless unit does not cause interference with the other system. A bandwidth control method in a base station device that is included in a non-public cellular network and that performs TDD wireless communication, the base station device comprising: first and second wireless units that perform wireless communication with a user device by using a predetermined frequency band; a control unit that controls the first and second wireless units; and a receiving unit that receives a synchronization signal, the base station device being included in a non-public cellular network and performing TDD wireless communication, the method comprising:
a step of determining whether the synchronization signal has been normally received by the receiving unit;
a step of, when the synchronization signal cannot be normally received by the receiving unit, allocating, in the control unit, a first frequency band among the predetermined frequency bands to the first wireless unit, and allocating a second frequency band among the predetermined frequency bands to the second wireless unit, as a frequency band for performing the wireless communication.

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