JP2019146059A - Base station device, terminal device, control method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an unnecessary access attempt by a terminal device to a backhaul line between a base station device and a relay device. A base station apparatus transmits a broadcast signal including information indicating whether or not the base station apparatus is using radio resources for a backhaul line. The terminal device receives a notification signal from the base station device including information indicating whether or not the base station device is using radio resources for the backhaul line, and based on the information, the terminal device is sent to the base station device. On the other hand, it is determined whether or not to request a connection. [Selection diagram] Fig. 5

Description

  The present invention relates to a connection control technique in a wireless communication network.

  In the third generation partnership project (3GPP), a relay communication technique for enabling communication between a base station apparatus and a distant terminal is discussed (see Non-Patent Document 1 and Non-Patent Document 2). This relay communication technology can be used on a backhaul line established between a base station device (donor node) and a relay device (relay node), and an access line for a terminal device to connect to the base station device or the like. The frequency band may be common (see Non-Patent Document 2). Moreover, establishment of the connection between a base station apparatus and a relay apparatus is performed similarly to the procedure in which the conventional terminal device connects to a base station apparatus (refer nonpatent literature 1).

3GPP TR 36.806, V9.0.0, March 2010 3GPP TR 36.826, V11.0.0, September 2012

  When a common frequency band is used for the backhaul line and the access line, when the base station apparatus establishes the backhaul line with the relay apparatus or after the establishment, the terminal apparatus connects to the base station apparatus unintentionally. It is possible to try. In other words, the base station device transmits a synchronization signal and a notification signal at regular intervals so that a backhaul line can be established when the relay device is activated / restarted. However, the connection procedure between the backhaul line and the access line is different. Since it is common, the terminal apparatus can try to access the base station apparatus based on this synchronization signal or broadcast signal. Although the base station apparatus can establish a connection with the terminal apparatus, if such an access attempt by the terminal apparatus is unnecessarily performed, a sufficient communication speed may not be obtained on the backhaul line.

  The present invention has been made in view of such a problem, and provides a technique for preventing an unnecessary access attempt from a terminal device to a backhaul line between a base station device and a relay device.

  A base station apparatus according to an aspect of the present invention is configured to transmit a notification signal including information indicating whether or not the base station apparatus uses a radio resource for a backhaul line.

  Further, the terminal device according to an aspect of the present invention receives a notification signal including information indicating whether or not the base station device uses a radio resource for a backhaul line from the base station device. Based on the above, it is configured to determine whether or not to request connection to the base station apparatus.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that the trial of the unnecessary access by the terminal device with respect to the backhaul line between a base station apparatus and a relay apparatus is made.

It is a figure which shows the structural example of the radio | wireless communications system accompanied by relay transmission. It is a figure which shows the hardware structural example of an apparatus. It is a figure which shows the function structural example of a base station apparatus. It is a figure which shows the function structural example of a terminal device. It is a figure which shows the 1st example of the flow of a process. It is a figure which shows the 2nd example of the flow of a process. It is a figure which shows the 3rd example of the flow of a process.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(System configuration)
FIG. 1 shows a configuration example of a wireless communication system according to this embodiment. This wireless communication system is configured with relay transmission, and in one example, includes a base station device 101, a relay device 102, and terminal devices 103 and 104. In FIG. 1, one base station apparatus 101, one relay apparatus 102, and two terminal apparatuses 103 and 104 are described. However, there can be many base station apparatuses, relay apparatuses, and terminal apparatuses. . In FIG. 1, a single hop relay path is formed by one relay apparatus 102, but a multi-hop relay path may be formed by a plurality of relay apparatuses. Further, in FIG. 1, one relay path is formed by one relay apparatus 102, but a plurality of relay paths may be formed by a plurality of relay apparatuses. Further, for example, when the relay device 102 is connected to a plurality of relay devices, a relay route that branches in the relay device 102 may be formed. In other words, the topology of the relay route is not particularly limited, and any configuration may be used. In this wireless communication system, communication is performed in accordance with the 5th generation NR (New Radio) standard. However, communication is performed in accordance with a standard before the 5th generation such as LTE or a future standard that has not been formulated at present. The following discussion can also be applied when done.

  The base station apparatus 101 can form one or more beams 121 and 122, and at least one of them (the beam 121 in the case of FIG. 1) is used to form a backhaul line with the relay apparatus 102. A wireless link 111 is established. Then, the relay device 102 relays communication performed by the base station device 101 (for example, communication between the terminal device 103 and the base station device 101). The relay apparatus 102 is assumed to be a fixed station that does not move in one example, but may be a mobile station in some cases. However, in this embodiment, it is assumed that the radio link between the base station apparatus 101 and the relay apparatus 102 can ensure sufficiently good radio quality, and between the base station apparatus 101 and the relay apparatus 102 The wireless link is called a backhaul line (backhaul link).

  The backhaul line is established in the same procedure as the access line established between the terminal device and the base station device. That is, the relay apparatus 102 establishes synchronization using the synchronization signal transmitted by the base station apparatus 101, acquires various information using the broadcast signal, and then establishes radio resource control (RRC) connection with the base station apparatus 101. The communication is started by executing processing such as establishment of the communication. At this time, since the wireless communication environment is stable, for example, when the relay apparatus 102 is fixed, the base station apparatus 101 sets the transmission cycle of the synchronization signal and the notification signal for establishing the backhaul line to the access line. It may be longer than the transmission cycle for establishment. However, since these synchronization signals and notification signals are not transmitted, for example, it can be assumed that the terminal device 104 tries to establish an access line based on the synchronization signals and the notification signals. Since the backhaul line is generally used when relaying communication between a large number of terminal devices and the base station device 101, it is often necessary to ensure a sufficiently large communication capacity. However, if the access line is established together with the backhaul line, a part of the communication capacity is allocated to the access line, so that it is not easy to secure the communication capacity of the backhaul line. In addition, the base station apparatus 101 can also refuse to establish a radio link in response to a signal for attempting to establish an access line from a terminal apparatus. However, since it can be assumed that wireless or computing resources for the rejection are wasted or that a signal from the terminal device interferes with the backhaul line, an attempt to establish such an access line from the terminal device is made. It is important not to do it unnecessarily.

  The base station apparatus 101 of this embodiment uses radio resources for the backhaul line so that an attempt to establish an access line is not unnecessarily performed when or after the backhaul line is established. A notification signal including information indicating that is transmitted. For example, a predetermined field (for example, 1 bit) is secured in the broadcast signal, and the bit (bit string) in the field indicates that the base station apparatus transmitting the broadcast signal uses the radio resource for the backhaul line. It is configured to indicate whether it is in use. Here, it is described that a notification signal including “information indicating whether or not radio resources are used for a backhaul line” is transmitted, but this information is a request for establishing a connection by a terminal device. It may be arbitrary information indicating whether or not to limit the above. In one example, this information can be broadcast by a master information block (MIB) in a physical broadcast channel (PBCH). According to this, a terminal device that has established synchronization can recognize whether or not radio resources are used for the backhaul line in the base station device without connecting to the base station device. In addition, this information may be alert | reported by System Information Block (SIB) in a physical downlink shared channel (PDSCH).

  When the terminal device 104 receives such a notification signal, the base station device that is the transmission source of the notification signal recognizes whether or not the radio resource to which the notification signal is transmitted is used for the backhaul line. . Then, for example, when the radio resource is used as a backhaul line, the terminal apparatus 104 does not attempt to establish an access line using the radio resource, that is, the base station apparatus that is the transmission source of the notification signal Decide not to request a connection. On the other hand, for example, when the radio resource is not used as a backhaul line, the terminal apparatus 104 determines to request connection to the base station apparatus that is the transmission source of the broadcast signal. In this way, the terminal device 104 does not attempt to establish an access line with the radio resource used for the backhaul line, so it is easy to secure the communication capacity of the backhaul line.

  In addition, when the base station apparatus 101 can form the plurality of beams 121 and 122 as described above and can provide separate radio links, the base station apparatus 101 includes the information as described above for each of the plurality of beams. A notification signal may be transmitted. For example, in the example of FIG. 1, a backhaul line is established for the beam 121, but no backhaul line is established for the beam 122. In this case, the base station apparatus 101 transmits a notification signal including information indicating that the radio resource is used for the backhaul line in the beam 121, and uses the radio resource for the backhaul line in the beam 122. A notification signal including information indicating that the information has not been transmitted is transmitted. In this case, the terminal apparatus 104 receives a broadcast signal via at least one of these beams, and determines whether to request connection to the base station apparatus 101 based on the broadcast signal. For example, if the terminal device 104 can receive the broadcast signals of both the beams 121 and 122, the radio resource is used for the backhaul line in the beam 121, so that the connection via the beam 121 is established. It determines with not requesting with respect to the base station apparatus 101. FIG. On the other hand, since the radio resource is not used for the backhaul line in the beam 122, the terminal device 104 can request the base station apparatus 101 to establish connection via the beam 122.

  Moreover, the base station apparatus 101 may further transmit information indicating whether other base station apparatuses within a predetermined range from the position of the base station apparatus are using radio resources for the backhaul line. Here, the predetermined range may be determined as a range in which base station devices connectable to terminal devices that can receive a notification signal from the base station device 101 are distributed. In one example, a range of a circle centered on the base station apparatus 101 having a radius that is twice the receivable distance of the signal transmitted by the base station apparatus 101 can be set as the predetermined range. This information can also be transmitted by MIB, SIB, or the like. Upon receiving this information, the terminal device 104 can determine a base station device that requests connection based on this information. That is, the terminal device 104 selects a base station device that does not use radio resources for the backhaul line (or a beam that the base station device can provide a radio link) and connects to the base station device. May be required to be established. Thereby, it is possible to avoid the terminal device from trying to establish an access line with the radio resource used for the backhaul line.

  Note that the terminal apparatus 104 can exclude a base station apparatus or beam whose radio resources are used for the backhaul line by the above-described notification signal from the target of radio quality measurement for a certain period of time. . According to this, since the terminal device 104 does not measure the base station device or beam that uses the radio resource for the backhaul line for a certain period, it does not request connection establishment.

  For example, the base station apparatus 101 may further transmit a condition that allows the radio resource to be used as an access line. This condition can also be transmitted by MIB, SIB, etc. in an example. If the notified condition is satisfied, the terminal device 104 can request establishment of a connection even when radio resources are used for the backhaul line. Here, in one example, the condition may include at least one of an amount of transmission data or a required data communication speed being a predetermined value or less and an emergency call. According to this, in the condition that the communication capacity of the backhaul line is not significantly reduced, or when urgent communication such as an emergency call is necessary, the base station apparatus uses radio resources for the backhaul line. However, the connection with the terminal device can be established. In the terminal device, if all received broadcast signals indicate that radio resources are used for the backhaul line, that is, radio resources that are not used for the backhaul line exist around If not, the radio resource may be connected to the base station apparatus (or beam) used for the backhaul line. In this case, the terminal apparatus may transmit a connection establishment request signal together with information indicating that there is no base station apparatus (or beam) that does not use radio resources for the backhaul line. Good. Note that the base station apparatus may allocate radio resources to such a terminal apparatus to such an extent that the communication capacity of the backhaul line is not significantly reduced.

  The base station apparatus 101 uses the radio resource for the backhaul line when the usage amount of the radio resource used for the backhaul line (for example, the accumulated usage amount within a certain period) exceeds a predetermined amount. A notification signal including information indicating that the information is present may be transmitted. That is, even if the base station apparatus 101 uses radio resources for the backhaul line, if the usage amount is equal to or less than the predetermined amount, the base station apparatus 101 does not use the radio resource for the backhaul line. A notification signal including the information to be shown can be transmitted. According to this, the base station apparatus can tolerate a connection establishment request by the terminal apparatus when the amount of radio resources used for the backhaul line is small and the communication capacity is sufficient. . Note that the base station apparatus 101 may periodically update the information of the notification signal by periodically counting the usage amount of the radio resource through the backhaul line.

  In addition, the base station apparatus 101 includes information indicating that the radio resource is used for the backhaul line in a period of time corresponding to the usage amount of the radio resource used for the backhaul line. A notification signal may be transmitted. For example, when the usage amount of the radio resource used for the backhaul line is 30%, the base station apparatus 101 uses the backhaul line during the period of 30 + α% (α ≧ 0) in the entire period. A broadcast signal including first information indicating that radio resources are being used can be transmitted. On the other hand, in this case, in the remaining 70-α% period, base station apparatus 101 transmits a notification signal including second information indicating that radio resources are not used for the backhaul line. sell. According to this, the terminal device 104 can request a connection to the base station device 101 when receiving a notification signal including the second information. That is, even with this technique, the base station apparatus allows the terminal apparatus to establish a connection establishment request when the amount of radio resources used for the backhaul line is small and the communication capacity is sufficient. Can do.

  Below, the example of a structure of the base station apparatus and terminal device which perform the above-mentioned process and the flow of the process performed are demonstrated. Note that the above base station apparatus may be replaced with a relay apparatus. For example, the relay apparatus can transmit a notification signal including the above-described information for a radio link formed by the relay apparatus. That is, when a communication link is established including two or more relay devices, a relay device connected to another relay device notifies the above-described information regarding the backhaul line established between these relay devices. The signal may be transmitted in the signal. That is, the relay apparatus according to the present embodiment and the appended claims can be handled as the base station apparatus described above.

(Hardware configuration)
FIG. 2 shows a hardware configuration example of the base station apparatus 101 and the terminal apparatus 104. For example, the base station apparatus 101 and the terminal apparatus 104 have a hardware configuration as shown in FIG. 2, and include, for example, a CPU 201, a ROM 202, a RAM 203, an external storage device 204, and a communication circuit 205. In the base station apparatus 101 and the terminal apparatus 104, for example, the CPU 201 executes a program for realizing the functions of the base station apparatus 101 and the terminal apparatus 104 as described above, which are recorded in any of the ROM 202, the RAM 203, and the external storage device 204. Is done.

  Then, the base station apparatus 101 and the terminal apparatus 104 communicate with other apparatuses by controlling the communication circuit 205 by the CPU 201, for example. Note that the communication circuit 205 of the base station apparatus 101 can communicate with other base station apparatuses and other network nodes (for example, the external processing apparatus 131) through, for example, a wired line. Further, the communication circuit 205 of the base station apparatus 101 may be capable of wireless communication with the relay apparatus 102 and the terminal apparatus 104 by forming one or more (plural) beams. Further, in this case, the communication circuit 205 of the terminal device 104 uses at least one of the beams formed by the communication circuit 205 of the base station device 101 or the relay device 102 (in some cases, the beam formed by the relay device 102). The base station apparatus 101 is configured to be connectable to the base station apparatus 101 via the connection. In the configuration of FIG. 2, the base station apparatus 101 and the terminal apparatus 104 are schematically illustrated as having one communication circuit 205, but are not limited thereto, and may include a plurality of communication circuits. . For example, the base station apparatus 101 has a first communication circuit for wired communication with another base station apparatus 101 and a second communication circuit for wireless communication with the relay apparatus 102 and the terminal apparatus 104. Yes. In addition, the terminal device 104 may include, for example, a first communication circuit for NR and a first communication circuit for LTE (Long Term Evolution). In addition, the terminal device 104 may include a wireless communication circuit related to a standard other than cellular, such as a wireless LAN, and may further include a wired communication circuit used at the time of wired connection such as USB connection.

  Note that the base station apparatus 101 and the terminal apparatus 104 may include dedicated hardware for executing each function, or a part of the base station apparatus 101 and the terminal apparatus 104 may be executed by hardware and the other part may be executed by a computer that operates the program. Also good. All functions may be executed by a computer and a program.

(Functional configuration)
FIG. 3 shows a functional configuration example of the base station apparatus 101. As an example, the base station apparatus 101 includes a communication unit 301, a BH line use determination unit 302, a broadcast signal generation unit 303, another base station information acquisition unit 304, and a condition storage unit 305. Note that this functional configuration example is merely an example, and the base station apparatus 101 can have other functions as a general base station apparatus, and some or all of the functions in FIG. The apparatus 101 may not be provided.

  The communication unit 301 performs wireless communication with the relay device 102 and, in some cases, the terminal devices 103 to 104. The communication unit 301 can perform wireless communication in accordance with, for example, an NR (New Radio) standard, which is a fifth generation communication standard, or an earlier generation communication standard such as LTE. Note that the communication unit 301 may be able to form one or more beams with variable directivities using, for example, an antenna array including a plurality of antenna elements, but is not limited thereto. For example, the communication unit 301 may not form a beam using an omni antenna, or may perform communication using an antenna having a fixed directivity direction such as a parabolic antenna. In some cases, the communication unit 301 may be connected to the relay apparatus 102 using a parabolic antenna and connected to surrounding terminal apparatuses using an omni antenna or an antenna array. Even in such a case, since the terminal device 104 may receive a signal transmitted by the beam radiated from the parabolic antenna, the processing described in this embodiment can be executed.

  The BH line use determination unit 302 determines whether the base station apparatus 101 is using radio resources for the backhaul line. In one example, the BH line use determination unit 302 determines that the radio resource is used for the backhaul line when the communication unit 301 establishes the backhaul line with the relay apparatus 102. . In addition, the BH line use determination unit 302 receives the first beam in response to the communication unit 301 establishing a backhaul line with the relay apparatus 102 in the first beam among the plurality of formed beams. For the radio resource is used for the backhaul line. In this case, the BH line usage determination unit 302 determines that the second beam different from the first beam among the plurality of beams described above is not established with another relay apparatus. , It may be determined that the radio resource is not used for the backhaul line. Further, the BH line usage determining unit 302 monitors the actual usage amount of the radio resource in the established backhaul line, and when the usage amount exceeds a predetermined amount, the radio resource is used for the backhaul line. It can be determined that In this case, when the usage amount is equal to or less than the predetermined amount, the BH line usage determination unit 302 may determine that the radio resource is not used for the backhaul line, and the usage amount is as described above. When the amount is equal to or smaller than a second predetermined amount that is smaller than the fixed amount, it may be determined that the radio resource is not used for the backhaul line. When the second predetermined amount is used, when the usage amount is equal to or less than the predetermined amount and exceeds the second predetermined amount, the BH line usage determination unit 302 determines that the radio resource is used for a period of time according to the usage amount. A process may be performed to determine that is used for the backhaul line. Note that the length according to the usage amount may be a length having a positive correlation such as being proportional to the ratio between the amount of available radio resources and the actual usage amount. In this case, the BH line usage determination unit 302 outputs a determination result indicating that the radio resource is used for the backhaul line in a period of a length corresponding to the usage amount. A determination result that the resource is not used for the backhaul line may be output. Further, the BH line usage determination unit 302 is configured so that the radio resource is transmitted to the backhaul line during a period corresponding to the usage amount even when the usage amount exceeds the predetermined amount or is equal to or less than the second predetermined amount. A process may be performed to determine that it is being used for the purpose. That is, if the usage amount exceeds the above-mentioned predetermined amount, the BH line usage determination unit 302 may determine that the radio resource is used for the backhaul line for the entire period. Without setting an upper limit such as a fixed amount, it may be determined that the radio resource is used for the backhaul line in a period of a length according to the usage amount. Similarly, the BH line usage determining unit 302 may determine that the radio resource is not used for the backhaul line for the entire period when the usage amount is equal to or less than the second predetermined amount. It is not necessary to provide a lower limit such as the predetermined amount.

  Broadcast signal generation section 303 sets a field value indicating whether or not radio resources are used for the backhaul line using the determination result of BH line use determination section 302, and generates a broadcast signal. . For example, the notification signal generation unit 303 sets the value of this field to “1” according to the determination result that the radio resource is used for the backhaul line, and the radio resource is used for the backhaul line. The value of this field is set to “0” according to the determination result that it has not been performed. Note that this may be reversed, for example, when the value of this field is “0”, it may indicate that the radio resource is not used for the backhaul line. When a plurality of beams are formed in the communication unit 301, the notification signal generation unit 303 generates a separate notification signal for each beam, and whether or not radio resources are used for the backhaul line for each beam. Field can be set. In addition, the broadcast signal generation unit 303 uses the radio resource for the backhaul line in another base station apparatus (and a beam formed by the base station apparatus) acquired by the other base station information acquisition unit 304 described later. Information on whether or not the notification is made may be included in the notification signal. In this case, the broadcast signal generation unit 303 may include only information on other base station apparatuses / beams whose radio resources are not used for the backhaul line in the broadcast signal, or the radio resources are included in the backhaul line. Therefore, only information on other base station devices / beams used for the purpose may be included in the broadcast signal. In addition, the notification signal generation unit 303 indicates a condition in which a terminal device is permitted to make a connection request to a radio resource used for a backhaul line, which is stored in a condition storage unit 305 described later. May be included.

  The other base station information acquisition unit 304 acquires information on whether or not the radio resource is used for the backhaul line in another base station device within a predetermined range from the position of the base station device 101. For example, the other base station information acquisition unit 304 uses the X2 or Xn interface by wired or wireless communication to transmit radio resources from the other base station device to the base station device (or a beam formed by the base station device). Information on whether or not is used for the backhaul line. Further, the other base station information acquisition unit 304 can acquire, for example, at least one of identification information of a base station apparatus that uses a radio resource for a backhaul line and beam identification information. Note that the base station apparatus 101 itself can also transmit information about whether or not the own apparatus is using radio resources for the backhaul line or identification information of the own apparatus to other base station apparatuses. Note that, when the base station apparatus 101 forms a plurality of beams, the base station apparatus 101 can transmit the identification information of the beam using the radio resource for the backhaul line. Note that the predetermined range may be, for example, a circle having a radius with a length twice as long as the receivable distance of a signal transmitted from the base station apparatus 101 centered on the base station apparatus 101. In addition, the predetermined range is, for example, that a general base station apparatus transmits a signal from a position where a signal transmitted by the base station apparatus 101 can be received by a beam using radio resources for a backhaul line. It may be determined as a range up to a position separated by a predetermined distance determined by the power that can be used. Further, the predetermined range may be a range of cells registered as cells having an adjacent relationship with the base station apparatus 101 (or the formed beam). In this case, the other base station information acquisition unit 304 can acquire the above information from a part or all of the base station devices corresponding to the cells registered in the neighboring cell list.

  The other base station information acquisition unit 304 may acquire the above-mentioned information by requesting information from other base station devices existing within a predetermined range, or may perform other requests without making a request. Information periodically transmitted from the base station apparatus may be received. Information regarding the other base station apparatus is input to the broadcast signal generator 303, and the broadcast signal generator 303 can generate a broadcast signal based on this information. At this time, the broadcast signal generation unit 303 transmits rough information as information on other base station devices existing at positions away from the base station device 101, and other base stations present at positions closer to the base station device 101. The broadcast signal may be generated so that detailed information is transmitted as information about the station apparatus. For example, as for information on other base station devices existing at positions close to the base station device 101, information on each of the beams formed by those base station devices can be included in the broadcast signal. On the other hand, for a distant base station apparatus, when any one of a plurality of beams uses a radio resource for a backhaul line, the radio resource is used for the backhaul line in the base station apparatus Information indicating that the notification has been made can be included in the broadcast signal. As described above, the transmitted information may be different depending on the distance from the base station apparatus 101. Note that information on other base station apparatuses is not essential, and the other base station information acquisition unit 304 may be omitted.

  The condition storage unit 305 stores a condition under which a wireless resource is allowed to be used as an access line when the wireless resource is used for a backhaul line. This condition may include, for example, at least one of a transmission data amount or a required data communication speed being a predetermined value or less and an emergency call. That is, it may be included as a condition that the communication is of a level that does not reduce the communication capacity of the backhaul line or that a connection needs to be urgently established. Note that the conditions may be set as appropriate by, for example, a telecommunications carrier that manages the base station apparatus 101, and conditions other than whether the amount of data / communication speed or an emergency call may be set. The notification signal generation unit 303 can generate a notification signal including information on the condition by referring to the condition stored in the condition storage unit 305 as necessary. In addition, when specific conditions, such as an emergency call, are provided in common by all the communication operators, the common conditions may not be included in the notification signal. This is because such conditions can be set in the terminal device in advance. Note that the base station apparatus 101 may reject all connection requests to the radio resources used for the backhaul line without using the above-described conditions. In this case, the condition storage unit 305 is omitted. Can be done.

  Next, an example of a functional configuration of the terminal device 104 will be described with reference to FIG. In one example, the terminal device 104 includes a communication unit 401, a connection availability determination unit 402, and a connection destination determination unit 403. Note that this functional configuration example is merely an example, and the terminal device 104 can have other functions as a general terminal device, and some or all of the functions in FIG. It may not be provided. Note that the terminal device 103 can also have a similar functional configuration.

  The communication unit 401 performs wireless communication with the base station apparatus 101 and the relay apparatus 102. The communication unit 301 can perform wireless communication in accordance with, for example, an NR (New Radio) standard, which is a fifth generation communication standard, or an earlier generation communication standard such as LTE.

  The connectivity determination unit 402 analyzes the notification signal received via the communication unit 401 and determines whether the radio resource to which the notification signal is transmitted is used for the backhaul line. For example, the connectivity determination unit 402 can confirm this specific field in the broadcast signal and make this determination depending on which bit of “0” or “1” is set in the field. In addition, when the base station apparatus 101 receives broadcast signals using a plurality of beams and the base station apparatus 101 receives at least a part of these broadcast signals, the radio network resources are backhauled for each beam. Determine if it is being used for a line. For example, the connection availability determination unit 402 does not request establishment of an access line for a base station apparatus or beam whose radio resources are used for a backhaul line.

  In addition, when the condition for allowing the establishment of the access line is described in the notification signal, the connection possibility determination unit 402 acquires and stores information on the condition. Then, when the terminal device 104 tries to connect to the network, the connection availability determination unit 402 determines whether or not the communication executed by the connection satisfies the acquired condition. Then, when the communication performed by the terminal device 104 does not satisfy the condition for the base station device or beam in which the radio resource is used for the backhaul line, the connectability determination unit 402 determines that base station device or beam. May not require establishment of an access line. On the other hand, if the communication performed by the terminal device 104 satisfies the conditions for the base station device or beam in which the radio resource is used for the backhaul line, the connection availability determination unit 402 satisfies the condition of the base station device or beam. It is determined that the request is permitted to establish the access line. Here, the conditions can include, for example, data amount, communication speed, emergency call, and the like as described above.

  Note that, in one example, the connection possibility determination unit 402 can exclude a base station apparatus or a beam that does not require establishment of an access line from a wireless quality measurement target for a certain period. This is because the terminal device 104 does not request connection for a base station device or beam that is excluded from the wireless quality measurement target.

  The connection destination determination unit 403 determines whether or not radio resources are used for the backhaul line in the other base station apparatus based on the notification signal received from the base station apparatus 101 (or the beam formed by the base station apparatus 101). If there is information, get that information and save it. Then, the connection destination determination unit 403 determines a target base station device or beam for requesting establishment of an access line based on the acquired information on the other base station device. For example, the connection destination determining unit 403 may not request establishment of an access line for another base station apparatus in which radio resources are used for a backhaul line or a beam formed by the base station apparatus. . That is, the connection destination determination unit 403 can determine a connection destination based on, for example, radio quality from among base station apparatuses or beams that do not use radio resources for the backhaul line. According to this, the terminal device 104 selects a neighboring base station device or a beam formed by those base station devices that is not used for the backhaul line, and sets it as the selected target. On the other hand, establishment of an access line can be requested.

  If there is no other base station device or relay device that can be connected to the surroundings, the terminal device 104 requests connection to the base station device whose radio resource is used for the backhaul line. Also good. In this case, for example, the terminal device 104 can transmit the connection request signal including information indicating that there is no device that can be connected in the vicinity. The base station apparatus 101 can permit connection to the terminal apparatus 104 in which such information is included. However, the base station apparatus 101 may give priority to the backhaul line, and may provide a communication service to the terminal apparatus 104 using radio resources that are not used on the backhaul line.

(Process flow)
Subsequently, some examples of the flow of processing executed in the wireless communication system according to the present embodiment will be described. In the following example, it is assumed that a 1-bit “BH use” field indicating whether or not radio resources are used for the backhaul line is prepared in the broadcast signal, and this value is “1”. Let some indicate that radio resources are being used for the backhaul line.

  FIG. 5 shows a first example of the flow of processing executed in the wireless communication system. In this process, the base station apparatus 101 has established a backhaul line with the relay apparatus 102 (S501). In this case, the base station apparatus 101 periodically transmits a broadcast signal in which the “BH use” field is set to “1” (S502). This notification signal is received by some or all of the communication devices (for example, the relay device 102 and the terminal device 104) that can receive the signal transmitted from the base station device 101. In addition, when the base station apparatus 101 forms a plurality of beams, a broadcast signal that specifies whether or not radio resources are separately used for the backhaul line in each of the plurality of beams Can be sent. Further, the base station apparatus 101 may set the “BH use” field to “1” from the time when the process for establishing the backhaul line is started, or after the process ends, Once established, the “Use BH” field may be set to “1”. When receiving the notification signal, the terminal device 104 extracts the value set in the “BH use” field. In this case, since “1” is set, the terminal device 104 confirms that the radio resource is used for the backhaul line in the transmission source of the broadcast signal (that is, the base station device 101). Can be identified. Then, the terminal device 104 determines not to make a connection request to the base station device 101 based on the identification result (S503).

  Thereafter, the base station apparatus 101 disconnects the backhaul line established with the relay apparatus 102 (S504). In response to the disconnection of the backhaul line, the base station apparatus 101 sets the “BH use” field in the broadcast signal to “0”. Note that the base station apparatus 101 may set the “BH use” field to “0” when the backhaul line disconnection process is started. The base station apparatus 101 transmits a notification signal in which the “BH use” field is set to “0” (S505). Upon receiving this notification signal, the terminal device 104 extracts the value set in the “BH use” field. In this case, since “0” is set, the terminal device 104 confirms that the radio resource is not used for the backhaul line in the transmission source of the broadcast signal (that is, the base station device 101). Can be identified. Based on this identification result, the terminal device 104 determines that the base station device 101 is allowed to request establishment of an access line (S506). And the terminal device 104 can request | require a connection with respect to the base station apparatus 101 in which a radio | wireless resource is not used for a backhaul line as needed (S507).

  Note that the base station apparatus 101 may transmit a notification signal in which the “BH use” field is set to “0” while maintaining a state where a backhaul line is established with the relay apparatus 102. For example, the base station apparatus 101 monitors the amount of communication actually executed on the established backhaul line, and sets the “BH use” field to “0” when the amount of communication is less than a predetermined amount. Yes. In addition, the base station apparatus 101 may provide a period for setting the “BH use” field to “0” and a period for setting “1” at a time ratio according to the traffic. That is, the base station apparatus 101 can set a period during which a connection request from a terminal apparatus is received and a period during which a connection request is not received, within a certain period, according to the amount of communication actually performed on the backhaul line. In this case, the terminal device 104 sets the connection destination to the base station device 101 or another base station device or relay device according to the value of the “BH use” field of the notification signal received during the period in which the access line should be established. Can be determined. According to such a technique, an appropriate amount of terminal device access is allowed according to the usage rate of the backhaul line in the base station device 101, so that access from an unnecessarily large number of terminal devices does not occur. can do.

  In this way, the terminal device 104 recognizes whether the base station device 101 is using radio resources for the backhaul line by monitoring a predetermined field of the broadcast signal transmitted by the base station device 101. Can do. Since the terminal device 104 does not request connection while the base station device 101 uses the radio resource for the backhaul line, the communication capacity of the backhaul line is prevented from decreasing due to the establishment of the access line. be able to. Further, since the terminal device 104 does not make a connection request, the processing load on the base station device 101 can be reduced.

  Next, a second example of the flow of processing executed in the wireless communication system will be described using FIG. In this example, in the broadcast signal, in addition to information on whether the radio resource is used for the backhaul line, a condition for permitting the connection request is notified. Note that, for example, a plurality of conditions are defined in advance, and information indicating which of the plurality of conditions is allowed to permit a connection request can be included in the notification signal. For example, a 3-bit condition designation field is prepared in the notification signal, and in the first bit, “1” is set when it is a condition that the amount of data to be communicated is a predetermined value or less. In the second bit, “1” is set when it is a condition that the requested communication speed is a predetermined value or less, and “1” is set when the condition is an emergency call in the third bit. May be. In this case, setting “0” may indicate that the connection request is not allowed even if the condition corresponding to the bit for which “0” is set is satisfied. For example, when this field is set to “011”, a connection request is not permitted even when the amount of data is small, but when the communication speed is below a predetermined level and when it is an emergency call Indicates that the connection request is allowed. Note that the predetermined value related to the data amount and the communication speed may be a fixed value determined in advance, or may be specified in another field in the notification signal. For example, a field indicating a data amount or a communication speed of a predetermined number of bits may be provided after the above-described 3-bit field. In this case, when the data amount or the communication speed is not used as a condition, the field indicating the data amount or the communication speed may be omitted.

  In FIG. 6, as in FIG. 5, a backhaul line is established between the base station apparatus 101 and the relay apparatus 102 (S501). In this case, the base station apparatus 101 sets the above-mentioned “BH use” field to “1” and transmits a notification signal including information on conditions under which a connection request is permitted (S601). Upon receiving this notification signal, the terminal device 104 first checks the “BH use” field, and determines that the connection request is permitted if the value of this field is “0”. On the other hand, in the case of FIG. 6, since the value of the “BH use” field is set to “1”, the terminal device 104 subsequently acquires information on conditions under which connection requests are permitted. Then, when requesting establishment of an access line, the terminal device 104 determines whether or not the acquired condition is satisfied (S602). If the condition is satisfied, the terminal device 104 requests connection to the base station device 101. can do. If the terminal device 104 does not satisfy the condition, the terminal device 104 does not make such a connection request to the base station device 101, and makes a connection request to another base station device or a relay device, for example. To do. As a result, connection is permitted for the terminal device 104 that does not significantly affect the communication capacity of the backhaul line or a limited condition such as an emergency call, and the terminal device 104 is maintained while maintaining the quality of the backhaul line. Necessary communication services can be provided.

  Then, the 3rd example of the flow of the process performed with a radio | wireless communications system is demonstrated using FIG. In this example, the base station apparatus 101 is information indicating whether or not the radio resource is used for the backhaul line not only in its own apparatus but also in other surrounding base station apparatuses (possibly relay apparatuses). Is transmitted in the notification signal (S701). Based on this information, the terminal device 104 determines a base station device or relay device to be connected (S702). For example, the terminal device 104 is a device that does not use radio resources for the backhaul line among the surrounding base station devices or relay devices and has a radio quality equal to or higher than a predetermined value. Can be determined as At this time, the terminal device 104 performs unnecessary measurement on a beam or the like for which a connection request is not allowed by, for example, excluding a wireless resource from a wireless quality measurement target for a device that is used for a backhaul line. Therefore, power consumption and processing load can be reduced.

  As described above, the terminal device 104 unnecessarily makes a connection request to the base station device 101 by transmitting whether or not the base station device 101 uses a radio resource for the backhaul line by a broadcast signal. No longer do. Therefore, the communication capacity and communication quality of the backhaul line can be kept high. Note that “whether or not radio resources are used for the backhaul line” may be read as “whether or not the connection request by the terminal device 104 is allowed” and whether or not the connection request is allowed. The determining factor does not necessarily have to be used on the backhaul line. That is, in any situation where it is necessary to avoid unnecessary connection requests by the terminal device 104, the above-described configuration and processing can be applied.

Claims (17)

A base station device,
Configured to transmit a notification signal including information indicating whether the base station apparatus is using radio resources for a backhaul line;
A base station apparatus. The base station apparatus can provide a separate radio link using a plurality of beams, and the information indicating whether or not the beam is used for a backhaul line in each of the plurality of beams. Transmitting the notification signal including:
The base station apparatus according to claim 1. Another base station device within a predetermined range from the position of the base station device is configured to further transmit information indicating whether or not a radio resource is used for a backhaul line,
The base station apparatus according to claim 1, wherein the base station apparatus is a base station apparatus. Configured to further transmit a condition that allows the radio resource to be used as an access line;
The base station apparatus according to claim 1, wherein the base station apparatus is a base station apparatus. The condition includes at least one of a transmission data amount or a required data communication speed being a predetermined value or less and an emergency call.
The base station apparatus according to claim 4. The notification including the information indicating that the base station apparatus is using radio resources for the backhaul line when the usage amount of radio resources used for the backhaul line exceeds a predetermined amount Send signal,
The base station apparatus according to claim 1, wherein the base station apparatus is a base station apparatus. The information including the information indicating that the base station device is using radio resources for the backhaul line in a period of time according to the usage amount of radio resources used for the backhaul line Send a notification signal,
The base station apparatus according to claim 1, wherein the base station apparatus is a base station apparatus. From the base station device, a notification signal including information indicating whether the base station device uses radio resources for the backhaul line is received,
Based on the information, determine whether to request a connection to the base station device,
A terminal device configured as described above. The base station apparatus can provide a separate radio link using a plurality of beams, and the information indicating whether or not the beam is used for a backhaul line in each of the plurality of beams. Transmitting the notification signal including
The terminal apparatus receives the broadcast signal via at least one of the plurality of beams, and requests connection to the beam formed by the base station apparatus based on information included in the broadcast signal Whether or not
The terminal device according to claim 8. The base station apparatus further transmits information indicating whether other base station apparatuses within a predetermined range from the position of the base station apparatus are using radio resources for the backhaul line,
The terminal apparatus receives the information and determines a base station apparatus to which the terminal apparatus should request connection based on the information.
The terminal device according to claim 8 or 9, wherein Based on the information received from the base station apparatus, the base station apparatus or beam used for the backhaul line is excluded from the target of radio quality measurement for a certain period.
The terminal device according to claim 8, wherein: Further receiving a condition that the radio resource is allowed to be used as an access line;
Determining whether to request connection to the base station apparatus based on whether or not the terminal apparatus satisfies the condition;
The terminal device according to claim 8, wherein the terminal device is a terminal device. The condition includes at least one of a transmission data amount or a required data communication speed being a predetermined value or less and an emergency call.
The terminal device according to claim 12. A control method for a base station apparatus,
Transmitting a notification signal including information indicating whether or not the base station device uses radio resources for a backhaul line;
The control method characterized by including. A terminal device control method,
Receiving a notification signal including information indicating whether or not the base station device is using radio resources for the backhaul line from the base station device;
Determining whether to request connection to the base station apparatus based on the information;
The control method characterized by including.   The program for functioning a computer as a base station apparatus of any one of Claim 1 to 7.   The program for functioning a computer as a terminal device of any one of Claims 8-13.

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