Base station apparatus, terminal apparatus, control method, and program

Abstract

To provide a base station apparatus, a terminal apparatus, and a control method, capable of suppressing interference between networks.SOLUTION: In a method, a base station apparatus of a second network in which communication is performed using time division duplex (TDD) in a frequency band different from a frequency band of a predetermined first network determines whether a terminal apparatus currently connected to the base station apparatus has detected a radio wave of the first network, on the basis of a first notification received from the terminal apparatus, and transmits, if it is determined that the terminal apparatus has detected the radio wave of the first network, to the terminal apparatus, a second notification for instructing to perform communication by setting a guard band for the frequency band used in the first network.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to interference suppression technology in wireless communication.

Background Art

[0002] The fifth-generation (5G) cellular communication standard standardized by the Third Generation Partnership Project (3GPP) has been put into practical use. In 5G, in addition to the networks deployed nationwide by communication carriers, local 5G that allows regions and companies other than communication carriers to deploy networks independently is available. In addition, regional BWA (Broadband Wireless Access), which is a network that can be deployed mainly by regions and companies other than communication carriers, is also known. Hereinafter, the network deployed nationwide by a communication carrier may be referred to as a carrier network, and the networks of local 5G and regional BWA may be referred to as local networks.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an environment where different networks coexist, such as a carrier network and a local network, it is important to suppress interference between mutual communications. In particular, it is necessary to suppress the interference caused by the communication of a network with a relatively low priority, such as a local network, to the communication of a network to be prioritized, such as a carrier network. The present invention provides an interference suppression technology between networks.

Means for Solving the Problems

[0005] A base station device according to an aspect of the present invention is Communication is performed using time-division duplex (TDD).In a frequency band different from that of the first network, T D D A base station device of a second network that communicates using D , wherein in a terminal device connected to the base station device, a first signal indicating that radio waves of a network different from the second network have been detected is received from the terminal device, Other Receiving means; and When the first allocation of uplink communication and downlink communication to time slots in the first network does not match the second allocation of uplink communication and downlink communication to time slots in the second network in some time slots, and the first signal is received from a first terminal device that is connected to the base station device and does not belong to the first network, and based on the first signal When radio waves of the first network are detected in the First Terminal device, is identified, and the first signal is not received from a second terminal device that is connected to the base station device and does not belong to the first network In this case, Instruct to communicate using a setting that prevents using a part of the frequency band in the second network that is close to the frequency band used in the first network A second signal is transmitted to the First Terminal device and does not transmit the second signal to the second terminal device Transmitting means.

Advantages of the Invention

[0006] According to the present invention, interference between networks can be suppressed.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

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Figure 8

Figure 9

Figure 10

Embodiment for Carrying Out the Invention

[0008] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0009] (System Configuration) FIG. 1 shows a configuration example of the system according to this embodiment. The system according to this embodiment is configured to include a plurality of networks. Here, the plurality of networks are all cellular communication networks compliant with the cellular communication standards of the 3rd Generation Partnership Project (3GPP). The first network is a carrier network 101 provided nationwide by a wireless communication carrier, and the second network is a local network 104 provided locally by a region, a company, or the like. The local network 104 is configured, for example, inside the area where the carrier network 101 is deployed. That is, the local network 104 is deployed in an overlapping area within the area where the carrier network 101 is deployed. Note that these are examples, and the following discussion can be applied to other forms of wireless communication networks.

[0010] In the carrier network 101, a wireless communication service is provided to the terminal device 103 of a user who has contracted with a wireless communication carrier in an area where wireless communication with the base station device 102 for providing the communication service of the carrier network 101 can be performed. Similarly, in the local network 104, a wireless communication service is provided to the terminal devices 106 and 107 prepared for local network communication in an area where wireless communication with the base station device 105 of the local network 104 can be performed. Here, in the present embodiment, the carrier network 101 is the network that should be prioritized, and the local network 104 communicates after performing processing so as not to interfere with the communication of the carrier network 101 or to have a sufficiently low level of interference.

[0011] It is conceivable that the carrier network 101 and the local network 104 communicate at their own timings. In this case, even if the carrier network 101 and the local network 104 communicate using, for example, orthogonal frequency division multiplexing (OFDM) that can ensure orthogonality with each other, orthogonality cannot be ensured due to the non - matching of the timings of the wireless frames, and interference may occur between them. Regarding this interference, for example, it can be suppressed by the base station device 105 transmitting and receiving wireless frames in synchronization with the base station device 102 of the carrier network 101 to match the timings of the wireless frames.

[0012] Note that there are multiple patterns of situations where interference occurs between each other. For example, as interference from the carrier network 101 to the local network 104, there may be (1) interference from the base station device 102 to the base station device 105, and (2) interference from the base station device 102 to the terminal devices 106 and 107. Also, interference from the carrier network 101 to the local network 104 includes patterns such as (3) interference from the terminal device 103 to the base station device 105, and (4) interference from the terminal device 103 to the terminal devices 106 and 107. Further, as interference from the local network 104 to the carrier network 101, there may be (5) interference from the base station device 105 to the base station device 102, and (6) interference from the base station device 105 to the terminal device 103. Also, interference from the local network 104 to the carrier network 101 may include (7) interference from the terminal devices 106 and 107 to the base station device 102, and (8) interference from the terminal devices 106 and 107 to the terminal device 103. At this time, on the premise that the local network 104 is inferior to the carrier network 101, the interferences (1) to (4) are allowed to a certain extent, and the local network 104 can perform processing to reduce the influence of this interference. On the other hand, since the interferences (5) to (8) are interferences to the prioritized network, the local network 104 must prevent such interferences from occurring or sufficiently suppress such interferences.

[0013] In one example, the interference in (5) can be sufficiently suppressed by the base station device 105 of the local network 104 transmitting a signal at the timing when the signal is transmitted by the base station device 102 of the carrier network 101. Also, by making the frequency band of the signal transmitted and received by the base station device 102 of the carrier network 101 different from the frequency band of the signal transmitted and received by the base station device 105 of the local network 104, the interferences in (6) and (7) can be suppressed to be sufficiently small. Also, the interference in (8) can be sufficiently suppressed by the terminal devices 106 and 107 of the local network 104 transmitting signals at the timing when the signal is transmitted by the terminal device 103 of the carrier network 101.

[0014] On the other hand, in recent cellular communication standards, a time-division duplex (TDD) system has been standardized that can flexibly change the ratio between the downlink in which signals are transmitted from a base station device to a terminal device and the uplink in which signals are transmitted from the terminal device to the base station device. Generally, since the demand for downlink communication is high, in the carrier network 101, there is a tendency to allocate more time slots to the downlink. On the other hand, depending on its use, the local network 104 may be assumed to require more time slots for the uplink than the carrier network 101. In this case, independently of the allocation of time slots to the uplink and downlink in the carrier network 101, the local network 104 can allocate time slots to the uplink and downlink (see Patent Document 1). However, in this case, the interferences (5) and (8) described above will occur.

[0015] In contrast, in the local network 104, it is possible to use only a part of the time slot allocation in the carrier network 101 after changing it. In one example, it is possible to allocate only a part of the slots allocated to the uplink in the carrier network 101 to the downlink, and use the slots allocated to the downlink in the carrier network 101 as they are for the downlink. Also, it is possible to allocate only a part of the slots allocated to the downlink in the carrier network 101 to the uplink, and use the slots allocated to the uplink in the carrier network 101 as they are for the uplink. According to the former setting, while downlink communication is being performed in the carrier network 101, since the terminal devices 106 and 107 do not transmit signals, the interference (8) can be suppressed. On the other hand, according to the latter setting, while uplink communication is being performed in the carrier network 101, since the base station device 105 does not transmit signals, the interference (5) can be suppressed.

[0016] Here, from the perspective of protecting the base station device 102 of the carrier network 101, the case of using settings without the interference in (5) will be considered. An example of the time slot setting in this case is shown in FIG. 2. In FIG. 2, the time slots assigned to the uplink communication are indicated by "U", the time slots assigned to the downlink communication are indicated by "D", and the time slots indicating the period of switching from the downlink to the uplink are indicated by "S". Note that the communication for allocating the time slots of the local network 104 by changing the communication direction (uplink or downlink) of a part of the time slot allocation of the carrier network 101 can be called quasi-synchronous TDD communication (see Patent Document 1). In the present embodiment, in particular, as shown in FIG. 2, the communication using the TDD pattern in which the time slots assigned to the downlink in the time slots of the carrier network 101 are used as the uplink in the local network 104 is referred to as quasi-synchronous TDD.

[0017] In the TDD time slot pattern (hereinafter referred to as "TDD pattern") of the carrier network 101 shown in FIG. 2, out of 20 time slots (subframes), 4 (time slot numbers: 4, 5, 14, and 15) are assigned to the uplink communication. And in the TDD pattern of the carrier network 101, out of the remaining 16 time slots, 14 time slots excluding 2 time slots for switching from the downlink communication to the uplink communication are assigned to the downlink communication. On the other hand, in the TDD pattern of the local network 104, a part of the time slots (time slot numbers: 8, 9, 18, and 19) assigned to the downlink in the TDD pattern of the carrier network 101 are assigned to the uplink communication. Note that in the TDD pattern of the local network 104, all the time slots assigned to the uplink communication in the carrier network 101 are used for the uplink communication. By using such a TDD pattern, in the local network 104, the uplink communication can be speeded up, and for example, the delay of the uplink communication can be reduced and the reliability can be improved.

[0018] By preventing the local network 104 from performing downlink communication at the timing when uplink communication is performed on the carrier network 101, when the base station device 102 of the carrier network 101 receives a signal, the base station device 105 of the local network 104 stops sending signals. Therefore, it is possible to prevent interference from the base station device 105 of the local network 104 to the signal received by the base station device 102 of the carrier network 101. Note that signals transmitted from the terminal devices 106 and 107 of the local network 104 may interfere with the signals received by the base station device 102 of the carrier network 101, but the power is significantly smaller than the signals transmitted from the base station device 105 of the local network 104. Also, the power of the signals from the terminal devices 106 and 107 of the local network 104 can be made sufficiently small under the control of the base station device 105 of the local network 104. Therefore, it is also possible to sufficiently suppress the interference to the base station device 102 of the carrier network 101 caused by the signals transmitted from the terminal devices 106 and 107 of the local network 104.

[0019] On the other hand, when the time slot allocated for downlink communication in the TDD pattern of the carrier network 101 is allocated for uplink communication of the local network 104, interference occurs to the signal received by the terminal device 103 of the carrier network 101. This interference is caused by the signals transmitted by the terminal devices 106 and 107. In this case, due to the short distance between the terminal device 103 and the terminal devices 106 and 107, even if the transmission power of the signals of the terminal devices 106 and 107 is small, they may strongly interfere with the received signal of the terminal device 103. In one example, interference can be suppressed by using different frequency bands for the carrier network 101 and the local network 104. However, in this case, due to the overly short distance between the terminal devices, the influence of interference due to out-of-band radiation may not be negligible.

[0020] In this embodiment, in view of the above circumstances, a technique for suppressing interference from the terminal devices 106 and 107 of the local network 104 to the terminal device 103 of the carrier network 101 is provided. In the following description, it is assumed that the carrier network 101 and the local network 104 use adjacent frequency bands. Here, the "adjacent frequency bands" can be, for example, two frequency bands obtained by dividing the frequency band assigned to 5G communication. Note that this is just an example, and a part of the frequency bands used by the carrier network 101 and the local network 104 may overlap, or they may not be adjacent but may be frequency bands where interference can occur due to out-of-band radiation. In one example, the carrier network 101 may use a frequency band in the 4.5 GHz band, and the local network 104 may use a frequency band in the 4.6 GHz band. Also, although the case where TDD is used has been described in the above example, frequency division duplexing (FDD) may be used.

[0021] In this embodiment, when it is detected that the terminal devices 106 and 107 in the local network 104 may interfere with the terminal device 103 in the carrier network 101, a guard band is set to suppress the interference with the communication of the terminal device 103. For example, when the base station device 105, the terminal device 106, or the terminal device 107 in the local network 104 detects the signal of the carrier network 101, a guard band for the used frequency band of the carrier network 101 is set. That is, among the available frequency bands of the local network 104, a setting is made such that a part of the frequency band (for example, one or more sub-carriers) closer to the used frequency band in the carrier network 101 is not used. On the other hand, when the base station device 105, the terminal device 106, or the terminal device 107 in the local network 104 does not detect the signal of the carrier network 101, communication is performed without setting a guard band. Note that this control can be executed for each terminal device. That is, a guard band can be set for the communication of some terminal devices and not set for the communication of other terminal devices. For example, for a terminal device located at a position where it can strongly interfere with the communication of the carrier network 101, communication with a guard band set is performed, and for a terminal device located at a position where it is assumed that it hardly interferes with the communication of the carrier network 101, communication without setting a guard band can be performed.

[0022] According to this, hereinafter, the configurations of the base station device 105, the terminal device 106, and the terminal device 107 in the local network 104 that execute such processing, and an example of the processing flow will be described. Hereinafter, unless otherwise specified, the base station device 105 in the local network 104 is referred to as the "base station device", and the terminal devices 106 and 107 in the local network 104 are referred to as "terminal devices".

[0023] (Device Configuration) FIG. 3 shows an example of the hardware configuration of the base station device and the terminal device according to this embodiment. The base station device and the terminal device have, for example, as their hardware configuration, a control unit 301, a storage unit 302, a wireless communication unit 303, and an antenna control unit 304.

[0024] The control unit 301 is configured to include one or more processors such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). Note that the control unit 301 may be configured to include a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or the like. The storage unit 302 stores various types of information such as a control program executed by the control unit 301, control parameters, a TDD pattern to be used, and connection terminal device information. The control unit 301 controls the entire device by executing, for example, the control program stored in the storage unit 302. Also, in one example, the various operations described below are realized by the control unit 301 executing the control program stored in the storage unit 302.

[0025] The wireless communication unit 303 is configured to include a circuit for performing communication compliant with 3GPP cellular communication standards such as 5th generation (5G) New Radio (NR) compliant with the 3GPP standard or Long Term Evolution (LTE). The wireless communication unit 303 is configured to include, for example, a baseband chip or an RF (Radio Frequency) chip. The antenna control unit 304 controls the antenna for wireless communication by the wireless communication unit 303. Note that the antenna control unit 304 may be included in the wireless communication unit 303 or may exist separately from the wireless communication unit 303. The antenna controlled by the antenna control unit 304 may be, for example, an antenna operable in both frequency bands usable by each of the carrier network 101 and the local network 104. However, this is just an example, and the antenna may be, for example, an antenna operable only in the frequency band of the local network 104 or an antenna operable in other frequency bands.

[0026] FIG. 4 is a diagram showing a functional configuration example of the base station apparatus according to the present embodiment. As a functional configuration example, the base station apparatus includes a signal transmission unit 401, a signal reception unit 402, a data storage unit 403, a connection control unit 404, and a guard band setting processing unit 405. The signal transmission unit 401 and the signal reception unit 402 transmit and receive signals having a frame configuration defined in the 3GPP cellular communication standard. The data storage unit 403 stores software corresponding to the control to be executed, information related to cellular communication, and the like. The connection control unit 404 executes processing related to connection and disconnection of the terminal device to the cellular network, such as communication of radio resource control (RRC) messages, with the terminal device. Further, the connection control unit 404 can execute processing related to connection with the core network function. The guard band setting processing unit 405 receives from the terminal device a notification indicating whether or not radio waves of another network such as the carrier network 101 have been detected in the terminal device, and specifies whether or not radio waves of the carrier network 101 have been detected. Then, based on the specific result, the guard band setting processing unit 405 performs processing related to the guard band setting described later.

[0027] FIG. 5 is a diagram showing a functional configuration example of the terminal device according to the present embodiment. As a functional configuration example, the terminal device includes a signal transmission unit 501, a signal reception unit 502, a data storage unit 503, a connection control unit 504, a radio wave detection unit 505, and a guard band setting processing unit 506. The signal transmission unit 501 and the signal reception unit 502 transmit and receive signals having a frame configuration defined in the 3GPP cellular communication standard. The data storage unit 503 stores software corresponding to the control to be executed, information related to cellular communication, and the like. The connection control unit 504 executes processing related to connection and disconnection of the terminal device to the cellular network, such as communication of RRC messages, between the terminal device and the cellular network. The radio wave detection unit 505 detects a signal transmitted from another base station device different from the base station device during communication. The radio wave detection unit 505 receives, for example, a notification signal and checks information such as the PLMN-ID (Public Land Mobile Networks - IDentifier) and cell ID of the notification signal. Note that the cell ID is, for example, a Physical Cell Identifier. Then, the radio wave detection unit 505 can identify whether a signal from another base station device different from the base station device during communication has been received by determining whether the notification signal is a signal transmitted by the base station device during communication based on the checked information. Note that the radio wave detection unit 505 may detect not only signals from other base station devices but also signals transmitted by other terminal devices other than its own device. The guard band setting processing unit 506 performs processing related to the guard band setting described later.

[0028] (Flow of processing) An example of the processing flow executed by the base station device 105 of the local network 104 will be described with reference to FIG. 6. In the following, the case where the target to be controlled whether or not to set the guard band is the terminal device 106 will be described. However, this is just an example, and for example, the same control can be executed for any terminal device existing under the base station device 105 such as the terminal device 107. This processing is started, for example, in response to the base station device 105 of the local network 104 becoming communicable with the terminal device. In this processing, the base station device 105 receives a notification that the carrier network 101 has been detected from the terminal device 106, or a notification to cancel the guard band setting. Then, the base station device 105 instructs the terminal device 106 to set or cancel the guard band in the uplink communication of the terminal device 106 based on the received information. Note that this processing can be realized, for example, by the control unit 301 of the base station device 105 reading and executing a computer program stored in the storage unit 302. A dedicated hardware circuit for realizing the following processing may be included in the base station device 105, or for example, the wireless communication unit 303 may be configured to execute the following processing. Note that the processing in FIG. 6 is repeatedly executed while the base station device 105 is operating. In an example, when it is described that the processing ends below, the processing may be shifted to the determination processing of S601 or S602.

[0029] After the start of processing, the base station device 105 of the local network 104 first determines whether quasi-synchronous TDD communication using the frame configuration as shown in FIG. 2 is being performed in the cell provided by the own device (S601). If the base station device 105 is not performing quasi-synchronous TDD communication (NO in S601), the processing is terminated as it is. In the local network 104, in addition to quasi-synchronous TDD communication, synchronous TDD communication in which the allocation of time slots to uplink and downlink communication also matches can be performed. Here, when synchronous TDD communication is used, the signals transmitted from the terminal devices 106 and 107 of the local network 104 do not interfere with the received signals at the terminal device 103 in the carrier network 101. Therefore, in such a case, there is no need to execute the processing related to the guard band setting. Thus, when synchronous TDD communication is performed, the processing in FIG. 6 can be terminated as it is.

[0030] When the base station device 105 is performing quasi-synchronous TDD communication (YES in S601), it determines whether it has received a detection notification from the terminal device 106 indicating that the signal of the carrier network 101 has been detected (S602). Here, it is assumed that the terminal device 106 detects the signal of the carrier network 101, but it is not limited to this. For example, the terminal device 106 can detect the signal of any network that has priority over the local network 104 and whose signal transmitted from the terminal device 106 can interfere.

[0031] When the base station device 105 receives a detection notification from the terminal device 106 (YES in S602), it determines to use the guard band in the communication of the connected terminal devices (terminal device 106 and terminal device 107). That is, the base station device 105 changes the setting of the band used in the communication of the connected terminal devices to a band with a guard band provided (S603). On the other hand, when the base station device 105 does not receive a detection notification from the terminal device 106 (NO in S602), it determines whether it has received a release notification of the use of the guard band from the terminal device 106 (S607). When the base station device 105 does not receive this release notification from the terminal device 106 (NO in S607), it ends the process. When the base station device 105 receives this release notification from the terminal device 106 (YES in S607), it changes the setting of the band used in the communication of the connected terminal devices from a band with a guard band provided to a band without a guard band provided (S608).

[0032] And when the base station device 105 changes the band setting in S603 and S608, it transmits a message instructing the change of the band setting to the connected terminal devices (terminal device 106 and terminal device 107) (S604). Note that the base station device 105 may change only the band setting of the terminal device (for example, terminal device 106) that is the transmission source of the detection notification or the release notification in S603 and S608. That is, the base station device 105 may not change the band setting of the terminal device (for example, terminal device 107) that is not the transmission source of these notifications.

[0033] Then, if the base station apparatus 105 succeeds in this setting change (YES in S605), it ends the process. On the other hand, if the base station apparatus 105 fails in the setting change (NO in S605), it disconnects the connection with the terminal apparatus (e.g., terminal apparatus 106) that is the transmission source of the detection notification or the cancellation notification (S606) and ends the process. In this case, the base station apparatus 105 may maintain the connection with the terminal apparatus (e.g., terminal apparatus 107) that is not the transmission source of the detection notification or the cancellation notification. Further, the base station apparatus 105 may perform control so that the uplink communication of the terminal apparatus 106 is not performed in the time slot in which the downlink communication is performed in the carrier network 101, and may maintain the communication with the terminal apparatus 106. In this case, the base station apparatus 105 may perform control so that the uplink communication of the terminal apparatus 107 is performed in the time slot in which the downlink communication is performed in the carrier network 101.

[0034] Next, an example of the processing flow executed by the terminal devices 106 and 107 of the local network 104 will be described with reference to FIG. 7. This processing is started, for example, in response to the terminal devices 106 and 107 establishing a connection with the base station device 105. Also, this processing may be started, for example, in response to the terminal devices 106 and 107 receiving a predetermined instruction from the base station device 105. In this processing, the terminal devices 106 and 107 execute a detection process of the carrier network 101 and transmit a notification according to the result to the base station device 105. Then, the terminal devices 106 and 107 receive an instruction to set or release the guard band in the uplink communication determined by the base station device 105 based on the notification, and execute communication control based on the instruction. Note that this processing can be realized, for example, by the control units 301 of the terminal devices 106 and 107 reading and executing the computer program stored in the storage unit 302. A dedicated hardware circuit for realizing the following processing may be included in the terminal devices 106 and 107, or, for example, the wireless communication unit 303 may be configured to execute the following processing. Note that the processing in FIG. 7 can be repeatedly executed while the terminal devices 106 and 107 are connected to the base station device 105. In one example, when it is described below that the processing ends, the processing may be transferred to the determination processes of S701 and S702. Note that hereinafter, the terminal devices 106 and 107 are referred to as the "terminal device".

[0035] After the start of processing, the terminal device first determines whether it is performing quasi-synchronous TDD communication using the frame configuration as shown in FIG. 2 with the base station device 105 (S701). If the terminal device is not performing quasi-synchronous TDD communication (NO in S701), the processing ends as it is. When the terminal device is performing quasi-synchronous TDD communication (YES in S701), it executes the radio wave detection process for the carrier network 101 (S702). The terminal device, for example, executes the radio wave reception process in the frequency band used for the communication of the carrier network 101, and determines whether the radio wave of the carrier network 101 has arrived based on the PLMN-ID and cell ID of the signal received as described above. Also, the terminal device may determine whether surrounding terminal devices are transmitting signals in the frequency band of the carrier network 101. Note that this detection process can be executed, for example, over a predetermined period (for example, between one or more frames). Also, the detection process can be executed, for example, in the time slot in which uplink communication is performed in the carrier network 101. According to this, the terminal device can determine whether the terminal device 103 of the carrier network 101 exists around. Also, the detection process may be executed in the time slot in which downlink communication is performed in the carrier network 101. According to this, the terminal device can determine whether it exists at a position where downlink communication can be performed in the carrier network 101. Also, the terminal device may detect radio waves of other local networks, for example, in addition to or instead of the radio waves of the carrier network 101. Note that the detection process may be executed by the control unit 301, or may be executed in the wireless communication unit 303. Also, the radio wave detection process may be performed by another functional unit different from the control unit 301 and the wireless communication unit 303.

[0036] When the terminal device detects the radio wave of the carrier network 101 (YES in S702), it transmits a detection notification indicating that it has detected the radio wave of the carrier network 101 to the connected base station device 105 (S703). In one example, in response to the transmission of this detection notification to the base station device 105, the base station device 105 may notify the terminal device of an instruction to perform communication with a guard band as described above. When the terminal device receives, for example, an instruction to perform communication with a guard band from the base station device 105 (YES in S704), it determines whether it can accept the instruction (S705). For example, the terminal device may determine that it cannot accept the instruction when it does not have the ability to perform communication with a guard band or when a setting that prohibits such communication is set. Also, the terminal device may determine that it cannot accept the instruction when it cannot achieve the required communication capacity when performing communication with a guard band. These are just examples, and whether the instruction can be accepted may be determined based on other criteria. When the terminal device determines that it can accept the instruction (YES in S705), it transmits a notification indicating that it can accept the instruction to the base station device 105 (S706). As a result, the terminal device changes the setting so as to perform communication with a guard band in the uplink communication. Note that the base station device 105 and the terminal device may also perform communication with a guard band in the downlink communication. On the other hand, when the terminal device determines that it cannot accept the instruction (NO in S705), it transmits a notification indicating that it cannot accept the instruction to the base station device 105 (S707). In this case, the terminal device may continue communication with a band setting without a guard band under the control of the base station device 105, or may execute a process of disconnecting the connection with the base station device 105.

[0037] On the other hand, when the terminal device does not detect the radio wave of the carrier network 101 (NO in S702), it repeatedly executes the detection process. Then, when the terminal device does not continuously detect the radio wave of the carrier network 101 in a predetermined number of detection processes during communication with a bandwidth setting provided with a guard band (YES in S708, YES in S709), it transmits a cancellation notice of the guard band setting to the base station device 105 (S710). Note that the terminal device may transmit this cancellation notice to the base station device 105 when it does not detect the radio wave of the carrier network 101 for a predetermined time. In one example, in response to the transmission of this cancellation notice to the base station device 105, the base station device 105 may notify the terminal device of an instruction to perform communication without providing a guard band as described above. When the terminal device receives an instruction to perform communication without providing a guard band from the base station device 105 (YES in S704), it determines whether it can accept the instruction (S705). Then, the terminal device executes the process of S706 or S707 as described above according to the determination result. By determining whether the radio wave of the carrier network 101 cannot be detected in a predetermined number of detection processes or in a detection process over a predetermined time as in S708, it is possible to prevent the guard band from being cancelled due to the radio wave not being detected instantaneously. Note that when the terminal device does not detect the radio wave of the carrier network 101 while communicating with a bandwidth setting without a guard band (NO in S709), it ends the process as it is.

[0038] Note that the control of setting and releasing the guard band by the base station apparatus 105 can be performed using an RRC (Radio Resource Control) message (for example, an RRC Reconfiguration message). The configuration of the message in this case is shown in Fig. 8(A), and the flow of message transmission and reception between the base station apparatus 105 and the terminal apparatus 106 is shown in Fig. 8(B). In the present embodiment, the base station apparatus 105 includes, for example, an IE 803 including information related to guard band setting change in addition to the existing information element (IE) 802 of the RRC Reconfiguration message 801. Note that although Fig. 8(A) shows an example in which the IE 803 is included at the end of the RRC Reconfiguration message 801, it may be included at other positions. The base station apparatus 105 transmits, for example, as a process of S604, the RRC Reconfiguration message 801 including the IE 803 to the terminal apparatus 106 (F811). When receiving this RRC Reconfiguration message 801, the terminal apparatus 106 determines, in S705, whether it can accept the setting of the guard band based on the information included in the IE 803. Then, the terminal apparatus 106 transmits an RRC Reconfiguration Complete message including information indicating the determination result to the base station apparatus 105 (F812). Note that the setting by the RRC message is an example, and the guard band may be set by other signals. For example, when the terminal apparatus 106 can always operate according to the instruction of the base station apparatus 105, the base station apparatus 105 may notify the setting of the guard band by, for example, downlink control information (DCI) for uplink resource allocation. Note that the radio wave detection notification may be notified by, for example, uplink control information (UCI), or may be notified multiplexed with user data.

[0039] As described above, in the present embodiment, when the terminal device 106 of the local network 104 detects the radio wave of the carrier network 101, the base station device 105 executes control for setting a guard band and performing communication if the radio wave is detected. According to this, it is possible to suppress interference with the terminal device 103 of the carrier network 101 that may exist in the vicinity when the terminal device 106 transmits an uplink signal in a time slot in which downlink communication is performed in the carrier network 101. Further, when the terminal device 106 and the terminal device 107 can determine that the radio wave of the carrier network 101 is not detected and the communication of the carrier network 101 is not being performed around, they can perform high-speed and large-capacity uplink communication without using a guard band.

[0040] In the above example, it is determined whether the terminal device 106 or the terminal device 107 detects the radio wave of the carrier network 101, but this determination may be made by the base station device 105. That is, the terminal device 106 and the terminal device 107 may determine only whether they detect the radio wave of another network, and the base station device 105 may determine whether the detected radio wave is the radio wave of the carrier network 101. An example of the processing flow of the base station device 105 in this case is shown in FIG. 9, and an example of the processing flow of the terminal device 106 and the terminal device 107 is shown in FIG. 10. For the same processing as that in FIGS. 6 and 7, the same reference numerals are given and the description is omitted.

[0041] Terminal devices 106 and 107 detect radio waves of another network different from the network to which the own device belongs, not limited to the carrier network 101 (S1001 in FIG. 10), and transmit a detection notification to the base station device 105. Then, when the base station device 105 receives the detection notification (YES in S602), it determines whether the detected network is the carrier network 101 (S901). Then, when the detected network is the carrier network 101, the base station device 105 transfers the process to S603, and when the detected network is not the carrier network 101, the process ends. In one example, the detection notification includes parameters such as PLMN-ID and cell ID for the radio waves detected by the terminal devices 106 and 107, and the base station device 105 can make the determination in S901 based on the parameters. In another example, the detection notification may only indicate that radio waves from a network other than the network to which the terminal devices 106 and 107 belong have been detected. In this case, the base station device 105 executes radio wave detection processing in its own device, and for example, when radio waves transmitted in the carrier network 101 are detected, it may estimate that the network detected by the terminal devices 106 and 107 is the carrier network 101.

[0042] Note that in FIG. 10, when radio waves of another network are not detected by the terminal device through a predetermined number of detection processes or through detection processes for a predetermined period, the terminal device transmits a guard band release notification. However, it is not limited to this. For example, even when radio waves of another network are detected by the terminal device, if the base station device 105 continuously determines or determines over a predetermined period that the radio waves are not radio waves of the carrier network 101, the guard band may be released. In this case, even if the terminal device detects radio waves of another network and does not transmit a guard band release notification, the base station device 105 can determine that the setting of the guard band is unnecessary and instruct the terminal device to release the guard band. Thereby, it is possible to prevent the guard band from being set unnecessarily.

[0043] This process can also suppress interference with the terminal device 103 of the carrier network 101 that may exist in the vicinity when the terminal device 106 transmits an uplink signal in a time slot in which downlink communication is performed in the carrier network 101. Further, when the terminal device 106 and the terminal device 107 cannot detect the radio wave of the carrier network 101 and can determine that communication of the carrier network 101 is not being performed in the surroundings, they can perform high-speed and large-capacity uplink communication without using a guard band.

[0044] In the above-described embodiment, the technique for suppressing interference with the carrier network 101 has been described. However, the above-described process may be executed to suppress interference with a network other than the carrier network 101. That is, in the terminal device 106 and the terminal device 107, when radio waves of a predetermined network that should not interfere with the communication of the local network 104 are detected, uplink (and in some cases, downlink) communication with a set guard band can be performed. In the processes of FIGS. 6 and 7, for example, when a connection is established, information (for example, PLMN-ID or cell ID) regarding the network to be detected may be notified from the base station device 105 to the terminal device 106 and the terminal device 107. In the processes of FIGS. 9 and 10, for example, information of parameters (for example, information specifying PLMN-ID or cell ID) to be notified in the detection notification may be notified from the base station device 105 to the terminal device 106 and the terminal device 107 when a connection is established.

[0045] In the above example, the process for suppressing interference when uplink communication is performed in a non-preferred network at the timing when downlink communication is performed in a preferred network has been described. However, it is not limited to this. That is, by applying the above-described guard band setting to downlink communication, it is also possible to suppress interference when downlink communication is performed in a non-preferred network at the timing when uplink communication is performed in a preferred network.

[0046] The present invention can also be realized by supplying a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and causing one or more processors in a computer of the system or apparatus to read and execute the program. It can also be realized by a circuit (for example, ASIC) that implements one or more functions.

[0047] The invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the claims are appended to disclose the scope of the invention.

Description of Reference Numerals

[0048] 101: Carrier network, 102: Base station apparatus of carrier network, 103: Terminal apparatus of carrier network, 104: Local network, 105: Base station apparatus of local network, 106, 107: Terminal apparatuses of local network, 405, 506: Guard band setting processing unit, 505: Radio wave detection unit

Claims

A base station apparatus of a second network that communicates using time-division duplex (TDD) in a frequency band different from that of a first network that communicates using TDD, receiving means for receiving, from the terminal device connected to the base station apparatus, a first signal indicating that radio waves of another network different from the second network have been detected in the terminal device; when a first allocation of uplink communication and downlink communication to time slots in the first network does not match a second allocation of uplink communication and downlink communication to time slots in the second network in some time slots, and a first signal is received from a first terminal device that is connected to the base station apparatus and does not belong to the first network, and it is specified based on the first signal that radio waves of the first network have been detected in the first terminal device, and when the first signal is not received from a second terminal device that is connected to the base station apparatus and does not belong to the first network, transmitting means for transmitting a second signal to the first terminal device instructing it to communicate using a setting that does not use a part of the frequency band on the side closer to the frequency band used in the first network among the frequency bands used in the second network, and not transmitting the second signal to the second terminal device; A base station apparatus, characterized by comprising the above. The first signal includes an identifier that enables the base station apparatus to identify whether the other network is the first network, The base station apparatus further has specifying means for specifying, based on the identifier, that the terminal device that is the transmission source of the first signal has detected radio waves of the first network. The base station apparatus according to claim 1, characterized by this. Claim 3 When the first signal is received from a terminal device connected to the base station device, radio wave detection processing is executed. When radio waves from the first network are detected in the detection processing, the base station device further has specifying means for specifying that the network of the transmission source of the radio waves detected in the terminal device is the first network. The base station device according to claim 1, characterized in that.

4. The identifier is a PLMN-ID (Public Land Mobile Networks-Identifier) or a cell ID included in a signal received by the terminal device that is the transmission source of the first signal. The base station device according to claim 2, characterized in that.

5. The transmitting means does not transmit the second signal when the first allocation of uplink communication and downlink communication to time slots in the first network matches the second allocation of uplink communication and downlink communication to time slots in the second network in all time slots. The base station device according to any one of claims 1 to 4, characterized in that.

6. While the receiving means is communicating using the setting in a terminal device that is connected to the base station device and does not belong to the first network, when radio waves of the first network are not detected over a predetermined period or when radio waves of the first network are not detected in a predetermined number of the detection processes, a third signal is received from the terminal device, The transmitting means transmits a fourth signal instructing the terminal device to communicate without using the setting when the third signal is received from the terminal device. The base station device according to any one of claims 1 to 5, characterized in that.

7. While communicating using the setting in a terminal device that is connected to the base station device and does not belong to the first network, if the first signal is received from the terminal device, and if it is specified a predetermined number of times or for a predetermined period that it is not the first network in the detection process, the transmitting means transmits a fourth signal instructing the terminal device to communicate without using the setting. The base station device according to claim 3, characterized in that.

8. The second signal is a signal that instructs to communicate using the setting in uplink communication and does not instruct communication using the setting in downlink communication. The base station device according to any one of claims 1 to 7, characterized in that.

9. The transmitting means transmits the second signal to the terminal device by means of a radio resource control (RRC) message. The base station device according to any one of claims 1 to 8, characterized in that.

10. The first network is a cellular communication network provided nationwide, and the second network is a cellular communication network provided locally. The base station device according to any one of claims 1 to 9, characterized in that.

11. A terminal device that does not belong to a first network in which communication is performed using time division duplex (TDD), and belongs to a second network in which communication is performed using TDD in a frequency band different from that of the first network, Detection means for detecting radio waves from another network different from the second network; Transmitting means for transmitting a first signal indicating the result of the detection to the base station device to which the terminal device is connected; When the first allocation of uplink communication and downlink communication to time slots in the first network does not match the second allocation of uplink communication and downlink communication to time slots in the second network in some time slots, When it is specified that the first signal has been transmitted to the base station apparatus and the radio wave of the first network has been detected by the terminal apparatus based on the first signal in the base station apparatus, receiving means for receiving, from the base station apparatus, a second signal instructing to communicate using a setting for preventing use of a partial frequency band closer to the frequency band used in the first network among the frequency bands used in the second network; setting means for applying the setting after receiving the second signal; having When the first signal is not transmitted from the terminal apparatus to the base station apparatus and the radio wave of the first network is detected in another terminal apparatus that is connected to the base station apparatus and does not belong to the first network, the terminal apparatus transmits the uplink signal without using the setting while the other terminal apparatus is performing communication using the setting. A terminal apparatus characterized by the above.

12. The first signal includes an identifier that enables the base station apparatus to identify whether the other network is the first network. The terminal apparatus according to claim 11, characterized by this.

13. The first signal includes information indicating that the terminal apparatus has detected the radio wave of another network. When the base station apparatus receives the first signal, it executes a radio wave detection process. When the radio wave from the first network is detected in the detection process, it identifies that the network of the transmission source of the radio wave detected in the terminal apparatus is the first network. The terminal apparatus according to claim 11, characterized by this.

14. The identifier is a PLMN-ID (Public Land Mobile Networks-Identifier) or a cell ID included in the signal received by the terminal apparatus. The terminal apparatus according to claim 12, characterized by this.

15. The detection means does not perform the detection when the first allocation of the uplink communication and the downlink communication to the time slot in the first network coincides with the second allocation of the uplink communication and the downlink communication to the time slot in the second network in all time slots. The terminal device according to any one of claims 11 to 14, characterized in that.

16. The transmission means transmits a third signal indicating that the use of the setting should be cancelled to the base station device when the radio wave of the other network is not detected for a predetermined period or the radio wave of the other network is not detected in a predetermined number of the detection processes executed by the detection means while the setting means is using the setting. The terminal device according to any one of claims 11 to 15, characterized in that.

17. The second signal is a signal that instructs to communicate using the setting in the uplink communication and does not instruct to communicate using the setting in the downlink communication. The setting means applies the setting based on the instruction indicated by the second signal. The terminal device according to any one of claims 11 to 16, characterized in that.

18. When the receiving means receives a fourth signal instructing to communicate without using the setting while the terminal device is communicating using the setting, the setting means cancels the use of the setting based on the fourth signal. The terminal device according to any one of claims 11 to 17, characterized in that.

19. The receiving means receives a signal from the base station device by a radio resource control (RRC) message. The terminal device according to any one of claims 11 to 18, characterized in that.

20. The terminal device according to any one of claims 11 to 19, wherein the first network is a cellular communication network provided nationwide, and the second network is a cellular communication network provided locally.

21. A control method executed by a base station device of a second network in which communication is performed using time division duplex (TDD) in a frequency band different from that of a first network in which communication is performed using TDD, comprising: Receiving, from the terminal device connected to the base station device, a first signal indicating that radio waves of another network different from the second network have been detected in the terminal device; When a first allocation of uplink communication and downlink communication to time slots in the first network does not match a second allocation of uplink communication and downlink communication to time slots in the second network in some of the time slots, and the first signal is received from a first terminal device that is connected to the base station device and does not belong to the first network, and it is specified that radio waves of the first network have been detected in the first terminal device based on the first signal, and the first signal is not received from a second terminal device that is connected to the base station device and does not belong to the first network, transmitting, to the first terminal device, a second signal instructing to communicate using a setting that does not use a part of the frequency band on the side closer to the frequency band used in the first network among the frequency bands used in the second network, and not transmitting the second signal to the second terminal device; A control method characterized by including the above.

22. A control method executed by a terminal device that does not belong to a first network in which communication is performed using time division duplex (TDD) and belongs to a second network in which communication is performed using TDD in a frequency band different from that of the first network, comprising: Detecting radio waves from another network different from the second network; transmitting a first signal indicating the result of the detection to the base station apparatus to which the terminal apparatus is connected; when a first allocation of uplink communication and downlink communication to time slots in the first network does not match a second allocation of uplink communication and downlink communication to time slots in the second network in some of the time slots; when the first signal is transmitted to the base station apparatus and it is specified that radio waves of the first network have been detected by the terminal apparatus based on the first signal at the base station apparatus; receiving, from the base station apparatus, a second signal instructing to communicate using a setting for not using a part of the frequency band in the second network that is close to the frequency band used in the first network; after receiving the second signal, applying the setting; including; when the first signal is not transmitted from the terminal apparatus to the base station apparatus and radio waves of the first network are detected by another terminal apparatus that is connected to the base station apparatus and does not belong to the first network, the terminal apparatus transmits an uplink signal without using the setting while the other terminal apparatus is communicating using the setting. A control method characterized by this.

23. A program for operating a computer as the base station apparatus according to any one of claims 1 to 10.

24. A program for operating a computer as the terminal apparatus according to any one of claims 11 to 20.

Images