Base station apparatus, control apparatus, control method, and program for controlling reflection pattern of reflector

Abstract

To make it possible to efficiently operate a reflector that can change a reflection pattern.SOLUTION: A base station device transmits group information that specifies a group of reflection patterns that are part of a plurality of reflection patterns that can be set by a reflector for radio waves transmitted and received between the base station device and a terminal device using one or more reflectors to a control device corresponding to each of the one or more reflectors. After transmitting the group information, the base station device transmits, to the control device, pattern information that can specify a reflection pattern to be set on the reflectors from among the group of reflection patterns specified by the group information.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a technique for controlling a reflection pattern of a reflector.

Background Art

[0002] In mobile communication, a wireless communication service is provided to a terminal device existing at a position where radio waves transmitted by a base station device can be received. Therefore, it is important that the radio waves transmitted by the base station device appropriately reach the position of the terminal device. Particularly in recent wireless communication environments that tend to use high frequency bands, the wireless quality is likely to deteriorate. Therefore, it is assumed that the base station device forms a beam and improves the wireless quality by the gain of the beam. In addition, the use of a reflector that reflects radio waves toward an area with low wireless quality has been considered. Note that although the reflector can change the direction of signal reflection by changing its physical orientation, by using a metasurface reflector, radio waves can be reflected in various directions without changing the physical orientation. Non-Patent Document 1 describes a technique in which a base station device controls the radio wave reflection pattern in a reflector by transmitting control information to a control device of the reflector.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the technique described in Non-Patent Document 1, the reflection pattern of the reflector can be adaptively changed under the control of the base station apparatus side, but an efficient operation method thereof has not been studied.

Means for Solving the Problems

[0005] The present invention provides a technique for efficiently operating a reflector capable of changing a reflection pattern.

[0006] A base station apparatus according to an aspect of the present invention includes transmission means for transmitting a signal, and the transmission means transmits group information specifying a group of reflection patterns, which is a part of a plurality of reflection patterns that can be set by the reflector, for radio waves transmitted and received between the base station apparatus and a terminal apparatus by one or more reflectors, to a control device corresponding to each of the one or more reflectors. After transmitting the group information, pattern information capable of specifying a reflection pattern to be set in the reflector among the group of reflection patterns specified by the group information is transmitted to the control device.

[0007] A control device according to an aspect of the present invention is a control device for controlling the reflection pattern of a predetermined reflector, and includes reception means for receiving a signal from a base station apparatus, and control means for controlling the reflection pattern of the predetermined reflector based on the signal received from the base station apparatus. The reception means receives, from the base station apparatus, group information specifying a group of reflection patterns, which is a part of the plurality of reflection patterns that can be set by the reflector, for radio waves transmitted and received between the base station apparatus and a terminal apparatus by the predetermined reflector. After receiving the group information, pattern information capable of specifying a reflection pattern to be set in the predetermined reflector among the group of reflection patterns specified by the group information is received from the base station apparatus, and the control means controls the predetermined reflector to reflect radio waves in the reflection pattern indicated by the pattern information.

Effects of the Invention

[0008] According to the present invention, it becomes possible to efficiently operate a reflector capable of changing a reflection pattern.

Brief Description of Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] 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, and not all combinations of the features described in the embodiments are essential for the invention. Two or more of the features described in the embodiments may be arbitrarily combined. Also, the same or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0011] (Configuration of Communication System) Fig. 1 shows a configuration example of a wireless communication system according to this embodiment. The wireless communication system is, for example, a cellular communication system compliant with the cellular communication standard of the 3rd Generation Partnership Project (3GPP (registered trademark)). However, the discussion below can be applied to wireless communication systems compliant with any wireless communication standard. The wireless communication system is configured to include, for example, a base station device 101, a terminal device 102, and a terminal device 105. Here, assume that due to the influence of a shielding object such as a building, the terminal device 102 cannot receive the radio wave transmitted from the base station device 101 with sufficiently strong power. In this case, it is also assumed that the base station device 101 cannot receive the radio wave transmitted from the terminal device 102 with sufficiently strong power. In such a situation, a reflector 103 can be used to enable communication between the base station device 101 and the terminal device 102. The reflector 103 reflects the radio wave sent from the base station device 101 in a predetermined reflection pattern. Also, the reflector 103 reflects the radio wave sent from the terminal device 102 in a predetermined reflection pattern. Here, the reflection pattern is determined by the reflection phase set for the reflection elements constituting the reflector. For example, it corresponds to a combination of an incident pattern and an emission pattern. The incident pattern is a pattern indicating the gain of the reflector for each incident direction. That is, the incident pattern is a pattern such that the radio wave incident from a predetermined incident direction is hardly attenuated, and the radio wave incident from another incident direction is attenuated to almost zero. Similarly, the emission pattern is a pattern indicating the gain of the reflector for each emission direction. That is, the emission pattern is a pattern such that the radio wave emitted in a predetermined emission direction is emitted with high power, and almost no radio wave is emitted in another emission direction. Due to this reflection pattern, generally, the radio wave incident from the incident direction with a large gain is output to the emission direction with a large gain.

[0012] In Fig. 1, when radio waves cannot be directly transmitted and received between the base station device 101 and the terminal device 105, a reflector 106 can be used to relay the communication between the base station device 101 and the terminal device 105.

[0013] Note that the configuration in FIG. 1 is merely an example. For example, the number of reflectors that relay communication between the base station device 101 and the terminal device (e.g., terminal device 102 or terminal device 105) may be one, or may be three or more. Also, of course, a large number of terminal devices are assumed to exist. And some of the terminal devices may be configured to communicate via a reflector, while some other terminal devices may be configured to communicate directly with the base station device 101 without using a reflector. Further, the wireless communication system may include a large number of base station devices. In this case, in other base station devices as well, communication using a reflector may be performed in the same manner as the base station device 101.

[0014] The reflector 103 and the reflector 106 are configured to be able to change the radio wave reflection pattern. For example, the reflector 103 and the reflector 106 can be configured to change the reflection direction of the radio wave arriving from the base station device 101 or the radio wave arriving from the terminal device 102 or the terminal device 105 by physically controlling the posture of the reflector. Further, the reflector 103 and the reflector 106 may be, for example, an Intelligent Reflecting Surface (IRS). The IRS is configured to be able to form a reflection pattern with a predetermined direction and beam width by, for example, being composed of a plurality of reflection elements and adjusting the reflection phase for each reflection element. The reflector 103 and the reflector 106 are respectively connected to the control device 104 and the control device 107. Then, the control device 104 executes control for changing the reflection pattern with respect to the reflector 103. The control device 104 outputs, for example, a control signal for adjusting the reflection phase for each reflection element of the IRS to the reflector 103. Further, the control device 104 may output a control signal for changing the direction of the reflector 103 to the operating member that supports the reflector 103. Note that the control device 104 may be a device built into the reflector 103. Further, the control device 104 may be a device provided outside the reflector 103. Also, in FIG. 1, the control device 104 shows an example in the case of being connected to one reflector 103, but it may be connected to a plurality of reflectors. When the control device 104 is connected to a plurality of reflectors, it can be configured to be able to independently control the reflection patterns of the plurality of reflectors. The control device 107 can also be configured to control the reflection pattern of the reflector 106 in the same manner as the control device 104.

[0015] Here, it is assumed that the reflector 103 uses a reflection pattern that reflects the radio waves output from the base station apparatus 101 and arriving from direction 111 in the direction 112. In this case, it is assumed that the terminal device 102 cannot receive the radio waves output from the base station apparatus 101 and reflected by the reflector 103 with sufficient power. In this case, the reflection pattern of the reflector 103 can be changed so as to reflect the radio waves from the base station apparatus 101 in the direction 113 under the control of the control device 104.

[0016] The reflection patterns of the reflector 103 and the reflector 106 can be changed, for example, based on an instruction from the base station apparatus 101 (or a network node). In one example, the control device 104 and the control device 107 receive the signal 121 from the base station apparatus 101. Then, the control device 104 and the control device 107 set the radio wave reflection patterns of the connected reflectors 103 and 106 based on the signal 121. In the present embodiment, a technique for efficiently setting or changing the radio wave reflection patterns of the reflectors 103 and 106 in such a case is provided.

[0017] (Contents of processing) Hereinafter, a method for efficiently setting or changing the radio wave reflection pattern of the reflector will be described.

[0018] <Processing Example 1> In this processing example, setting information for setting the reflection patterns of the reflector 103 and the reflector 106 is notified to the control device 104 and the control device 107 by system information broadcast by the base station device 101. Here, the system information is, for example, a master information block (MIB) or a system information block (SIB) defined in the cellular communication standard of 3GPP (registered trademark). In this case, the control device 104 and the control device 107 are configured to have a function of receiving at least these system information and acquiring the setting information. However, this is merely an example, and in the radio communication standard to which the base station device 101 conforms, the above-described setting information may be included in information broadcast or multicast to a plurality of target devices (terminal devices and control devices).

[0019] The setting information includes, for example, identification information for identifying the reflector to be the target of the reflection pattern setting. With this identification information, when a plurality of control devices can receive the system information from the base station device 101, those control devices can specify whether the setting information included in the received system information is the setting information for the reflector corresponding to their own device. Also, when two or more reflectors are connected to the control device, the control device can specify, based on the identification information, which of those reflectors is the control target. That is, although the system information is received in parallel by one or more control devices corresponding to one or more reflectors, the identification information can be used to notify the setting information regarding a specific reflector. Note that the identification information may be applied to a group of reflectors. That is, a plurality of reflectors may be grouped, and the identification information for designating any one of the groups may be included in the setting information.

[0020] In addition, the setting information includes pattern information that enables the control device to identify the reflection pattern to be set by the reflector specified by the identification information. This pattern information can be, for example, information specifying which of a plurality of reflection patterns that can be set by the reflector should be set. That is, pattern identification information for identifying each of the plurality of reflection patterns that can be set by the reflector can be pre-assigned, and pattern identification information indicating which reflection pattern should be used can be notified as the pattern information. In one example, when the reflector can set 64 reflection patterns consisting of 8 incident patterns and 8 emission patterns, a combination of the incident pattern and the emission pattern to be set can be specified by 6-bit setting information. Also, the order in which the reflection patterns are switched may be determined in advance. In this case, 1-bit information indicating that the reflection pattern should be switched may be notified as the setting information. Also, in this case, explicit pattern information may be omitted. That is, the setting information may include only the identification information. The control device can switch to the next reflection pattern to be set in accordance with the order determined in advance without depending on the pattern information for the reflector including the identification information contained in the received setting information.

[0021] Further, if necessary, the configuration information may include timing information indicating the timing for changing (configuring) the reflection pattern. When the control device receives the configuration information including the timing information, for example, it controls the connected reflector so that the setting of the reflection pattern is completed at the timing indicated by the timing information. Note that the timing information can be included in the configuration information, for example, when the reflection pattern is switched at high speed. In one example, the base station device 101 can identify the radio quality of the terminal device for each reflection pattern of the reflector and determine the reflection pattern to be used for communication with the terminal device based on the radio quality. Therefore, the timing information can be used to share the recognition of when the reflection pattern is switched between the base station device 101 and the control device. On the other hand, when the same reflection pattern is used semi-permanently, it is assumed that the timing at which the reflection pattern is set is not important. Therefore, when the frequency of changing the reflection pattern is low, the timing information may not be included. Note that the timing information may or may not be included in the configuration information regardless of the frequency of changing the reflection pattern. Also, regardless of the frequency of changing the reflection pattern, the timing information may or may not be included in the configuration information.

[0022] In one example, the setting information may include a plurality of pattern information that can identify a plurality of reflection patterns respectively. In this case, the setting information may include a plurality of timing information regarding the timing at which each of the plurality of reflection patterns should be set. For example, a plurality of pattern information and a plurality of timing information may be included in the setting information so as to be able to specify setting the first reflection pattern at the first timing and setting the second reflection pattern at the second timing. Note that when the change order of the plurality of reflection patterns is determined, only the timing information may be notified. Also, for example, as the timing information, the first information indicating the first setting timing and the second information indicating the period may be notified. In this case, for example, the first reflection pattern may be set at the first setting timing indicated by the first information, and the second reflection pattern may be set at the timing when the period indicated by the second information has elapsed from the first setting timing. Also, the third reflection pattern may be set at the timing when the period indicated by the second information has elapsed from the timing when the second reflection pattern was set. In this way, setting information including timing information in any form that can identify a plurality of timings for sequentially setting a plurality of reflection patterns may be used. By including a plurality of pattern information indicating a plurality of reflection patterns respectively in one setting information and transmitting it as described above, the number of times the identification information of the reflector is transmitted can be reduced. Note that the timing information and the pattern information may be notified separately.

[0023] The base station device 101 may change the transmission frequency of the system information including the above-described setting information according to the change frequency of the reflection pattern. That is, the base station device 101 may transmit the system information including the setting information more frequently as the change frequency at which the reflection pattern is changed is higher. That is, a setting may be made such that the transmission frequency of the system information including the setting information when the change frequency of the reflection pattern is a first value is higher than the transmission frequency when the change frequency is a second value lower than the first value. According to this, in a state where the reflection pattern should be changed frequently, the system information including the setting information can be transmitted in a timely manner. Also, in a state where the change frequency of the reflection pattern is low, it is possible to prevent the system information including the setting information from being transmitted unnecessarily.

[0024] As described above, by changing the reflection pattern of the reflector using the system information transmitted by broadcast, it is possible to collectively control the reflectors existing within the range of the cell formed by the base station device 101. Thereby, it becomes possible to efficiently change the reflection pattern of the reflector and efficiently operate the system.

[0025] <Processing Example 2> In the above-described Processing Example 1, an example in which the identification information and pattern information of the reflector are included in the system information transmitted by broadcast has been described. On the other hand, in this processing example, a procedure for notifying the setting information for an individual reflector by individual signaling will be described. By using individual signaling, it is possible to prevent an increase in the data size of the system information when there are a large number of reflectors within the range of the cell formed by the base station device 101 or when the reflection pattern is changed very frequently.

[0026] The setting information transmitted by individual signaling includes the above-described pattern information. On the other hand, in the case of individual signaling, since the setting information is individually transmitted to the control device corresponding to the reflector, the identification information of the reflector may be omitted. In addition, when one control device corresponds to a plurality of reflectors, identification information indicating which of the plurality of reflectors should be the control target may be included in the setting information. Note that the pattern information may be pattern identification information that specifies a combination of an incident pattern and an emission pattern that can be set by the reflector as described above. Also, when a plurality of reflection patterns are sequentially switched and the order of the switching is determined, information indicating that the switching should be performed may be used as the pattern information. Further, timing information indicating the timing at which the reflection pattern should be set may be included in the setting information. Also, a plurality of pattern information may be included in one setting information. In this case, a plurality of timing information for specifying a plurality of timings at which each of the plurality of reflection patterns should be set may be included in the setting information.

[0027] Note that individual signaling can be performed using, for example, downlink control information (DCI). In this case, for example, a DCI format for controlling a reflector can be newly defined. Also, an existing DCI format may be reused. In the DCI, a field of a predetermined number of bits for indicating, for example, pattern information and timing information can be prepared. In this case, the control device decodes a physical downlink control channel (PDCCH). In one example, a radio network temporary identifier (RNTI) can be assigned to the control device in advance. In this case, the control device can obtain information from the DCI addressed to its own device by decoding the PDCCH using the RNTI. When the RNTI is assigned in advance, the control device can establish the time synchronization of the downlink (the link from the base station device 101 to the control device) only by observing the synchronization signal, and can decode the PDCCH. That is, in this case, the control device does not need to execute a random access procedure to establish the uplink synchronization or establish a connection in the radio resource control (RRC) layer with the base station device 101. Therefore, the connection establishment process and the like can be omitted, and the processing load can be sufficiently suppressed. Note that the RNTI to be used by the control device for decoding the DCI may be set to a unique value for each of one or more control devices, or may be set to a common value. Note that when a common RNTI is assigned to a plurality of control devices, identification information indicating which reflector is the control target can be specified in the setting information included in the DCI. Note that the control device may be configured to receive the DCI after establishing an RRC connection with the base station device 101. When there is DCI addressed to its own device, the control device acquires pattern information and timing information from the DCI and sets the reflection pattern of the reflector connected to its own device. The base station device 101 can transmit the setting information frequently by using the DCI. Therefore, when the reflection pattern of the reflector should be changed frequently, it is possible to appropriately transmit and receive the setting information by using the DCI.

[0028] Also, individual signaling may be performed using, for example, a Media Access Control (MAC) sub-header. That is, the base station device 101 transmits the above-described setting information to the control device as information in the MAC layer. The control device analyzes the MAC sub-header included in the signal addressed to itself to obtain the setting information. Then, the control device controls the reflector connected to its own device based on the setting information. To use the MAC sub-header, since the control device needs to establish an RRC connection with the base station device 101, the load for connection establishment processing and the like becomes larger compared to the case of using DCI based on the pre-assigned RNTI as described above. On the other hand, when the MAC sub-header is used, the control device transmits a confirmation response indicating whether the information has been accurately received to the base station device 101. For this reason, the base station device 101 can confirm whether the reflector is appropriately set and can perform highly reliable control. Also, the base station device 101 can transmit the setting information at high frequency by using the MAC sub-header.

[0029] Also, individual signaling may be performed using an RRC message (for example, an RRC Reconfiguration message). That is, when the control device receives an RRC message, it extracts the setting information included in the message. Then, the control device controls the reflector connected to its own device based on the extracted setting information. The RRC message is not a message transmitted frequently, but can contain a lot of information. For this reason, for example, the base station device 101 can include a number of reflection patterns and information on the timing at which each of those reflection patterns should be applied in the RRC message and transmit them at once. Also, when the RRC message is used, the control device transmits a confirmation response indicating whether the message has been accurately received to the base station device 101. For this reason, the base station device 101 can confirm whether the reflector is appropriately set and can perform highly reliable control.

[0030] In addition, a protocol layer for signaling for controlling the reflector may be defined. The control device may receive a message of the protocol layer and control the reflector connected to the own device based on the setting information included in the message. By defining a new protocol layer, it becomes possible to use a message format suitable for controlling the reflector.

[0031] Note that the above-described individual signaling methods may be used in combination. In one example, it may be configured such that setting information is transmitted and received by combining an RRC message and a MAC sub-header. Combinations of other messages are of course possible.

[0032] As described above, by changing the reflection pattern of the reflector using individual signaling, it is possible to appropriately set the reflection pattern for each individual reflector. Thereby, it becomes possible to efficiently change the reflection pattern of the reflector and operate the system efficiently.

[0033] <Processing Example 3> The method of Processing Example 1 and the method of Processing Example 2 may be used in parallel. In one example, for the transmission and reception of the setting information for the reflector, either individual signaling or broadcast transmission can be selectively used according to the situation. Information specifying which of individual signaling and broadcast transmission should be used can be notified as system information in one example. For example, a 1-bit information field is prepared in the system information (MIB or SIB), and it can be indicated which of individual signaling and broadcast transmission is used. Also, when individual signaling should be used, information that can identify the individual message to be used for the transmission and reception of the setting information may be included in the system information and notified to the control device. Also, for example, information on the RNTI that the control device should use for decoding the DCI may be included in the system information and notified to the control device. Here, when individual RNTIs are set for one or more control devices, it is necessary to include a lot of information in the system information, but the data volume of the individual signaling of the setting information by the subsequent DCI can be reduced. On the other hand, when a common RNTI is set for one or more control devices, the data volume of the RNTI to be notified in the system information can be reduced.

[0034] Note that the base station device 101 can determine whether to use individual signaling or broadcast transmission, for example, according to the number of reflectors existing within the range of the cell formed by the base station device 101. For example, the base station device 101 can determine to use individual signaling when the number of its reflectors exceeds a predetermined number. Thereby, it is possible to prevent the capacity of the setting information transmitted by broadcast from increasing without limit. On the other hand, the base station device 101 can determine to use broadcast transmission when the number of its reflectors does not exceed a predetermined number. According to this, while keeping the capacity of the setting information transmitted by broadcast constant, the reflectors can be efficiently controlled by simultaneous notification.

[0035] In addition, the base station apparatus 101 can determine whether to use individual signaling or broadcast transmission, for example, according to the change frequency of the reflection pattern of the reflector. For example, the base station apparatus 101 can determine to use individual signaling when the change frequency of the reflection pattern of the reflector exceeds a predetermined value. In one example, the base station apparatus 101 makes such a determination when using individual signaling that requests the establishment of an RRC connection. According to this, between the control device corresponding to the reflector with a high change frequency of the reflection pattern, an RRC connection can be established once, and then a plurality of individual signalings can be performed while maintaining the connection. On the other hand, the base station apparatus 101 can determine to use broadcast transmission when the change frequency of the reflection pattern of the reflector does not exceed a predetermined value. According to this, for example, an increase in the processing load due to establishing an RRC connection each time individual signaling is used can be suppressed.

[0036] In addition, the base station apparatus 101 may determine whether to use individual signaling or broadcast transmission according to the combination of the number of reflectors and the change frequency of the reflection pattern.

[0037] (Configuration example of pattern information) As described above, a combination of an incident pattern and an emission pattern that can be set by the reflector can be specified as a reflection pattern. At this time, when the incident pattern and the emission pattern are set so as to obtain sufficient gains respectively, it becomes possible to perform communication between the base station device 101 and the terminal device with high quality. On the other hand, when the incident pattern and the emission pattern are set so as to obtain sufficient gains respectively, the beam width tends to become narrow. Here, the beam width is defined by the difference in direction between the direction in which the peak of the beam gain is obtained and the direction in which the gain is attenuated by a predetermined value (for example, 3 dB). For example, when the peak of the beam gain is obtained at 45°, and the gain becomes 3 dB lower than the peak at 42° and 48°, the beam width is 48 - 42 = 6°. If the beam width of each reflection pattern is narrow, in order to cover the entire of a certain geographical range using the reflector, it is necessary to be able to set a combination (reflection pattern) of a large number of incident patterns and emission patterns. And when the number of settable reflection patterns increases, the number of bits for specifying which of those reflection patterns should be used increases. For example, when there are 64 types of incident patterns and emission patterns respectively, a total of 4096 types of reflection patterns will be prepared. As a result, 12 bits are required for specifying one reflection pattern. Therefore, when frequently changing the reflection pattern, 12 bits are required each time the reflection pattern is changed, and the data amount of the pattern information becomes too large. For this reason, in order to efficiently set the reflection pattern of the reflector, it may be important to provide a mechanism for reducing the amount of information for specifying the reflection pattern.

[0038] In one example, as a method for reducing the amount of information for specifying a reflection pattern, available reflection patterns are classified into a plurality of groups, and information indicating which group to use is notified from the base station device 101 to the control device. Thereafter, the base station device 101 transmits pattern information indicating which reflection pattern should be used among the groups it uses to the control device. For example, 4096 reflection patterns can be classified into 64 groups. In this case, the number of reflection patterns included in one group is 64. In this example, the base station device 101 notifies 6 bits of information in one group specification. Thereafter, the base station device 101 notifies 6 bits of information for specifying a reflection pattern within the group. Here, while the group is not changed, there is no need to resend the information specifying the group. Therefore, while the group is not changed, 6 bits of information are sufficient for transmission and reception for switching the reflection pattern. Therefore, by enabling the reflection patterns belonging to the same group to be continuously used, the setting of the reflection pattern of the reflector can be efficiently performed.

[0039] In one example, for instance, it may be assumed that the positional relationship between the base station device 101 and the reflector is fixed. In this case, for example, the pattern directed toward the base station device 101 can be specified as one or a small number (a part). That is, only a part of a plurality of patterns regarding the direction in which radio waves propagate between the reflector and the base station device 101 can be selected and settable at the reflector. Therefore, among the reflection patterns of the reflector, grouping of reflection patterns can be performed such that the patterns directed toward the base station device 101 are limited to a small number and the patterns directed toward the terminal device are not limited. According to this, in an environment where the communication situation such as the positional relationship between the base station device 101 and the reflector does not change, the reflection patterns to be used can be limited. As a result, the base station device 101 first transmits information specifying the group corresponding to the positional relationship between the base station device 101 itself and the reflector, and then notifies the control device of the pattern information specifying the reflection pattern between the terminal device and the reflector. Thereby, as long as there is no change in the positional relationship between the base station device 101 and the reflector, the amount of information of the pattern information transmitted from the base station device 101 to the control device can be reduced. Note that when the state between the base station device 101 and the reflector changes, such as when the reflector is a movable reflector, group switching is performed. In this case, the base station device 101 can specify the direction from the reflector toward the base station device 101 according to the change in the positional relationship between the base station device 101 and the reflector, and determine to use the group corresponding to that direction. As an example, as an initial setting of the reflector, a predetermined signal is output while changing the radio wave radiation pattern from the reflector, and the base station device 101 can specify how much power the predetermined signal was received with. The base station device 101 can specify the direction of the base station device 101 as seen from the reflector by specifying the radio wave radiation pattern used at the reflector when the predetermined signal was received with sufficient power. Then, the base station device 101 specifies the group of reflection patterns corresponding to the specified direction, and notifies the control device of the information specifying the group. After that, within the group, pattern information enabling the specification of the reflection pattern corresponding to the direction of the terminal device as seen from the reflector can be notified from the base station device 101 to the control device.

[0040] Also, in another example, for instance, it may be assumed that the area where the radio quality is to be improved by the reflector is limited. In such a case, it is not necessary to use a reflection pattern in which a peak appears in the direction of a terminal device existing outside the area where the radio quality is to be improved. For this reason, a group of reflection patterns excluding those reflection patterns in which the peak of the gain is directed in a direction other than the area where the radio quality is to be improved can be specified as a group of configurable reflection patterns. That is, among the reflection patterns of the reflector, grouping of reflection patterns can be performed such that the patterns directed toward the terminal device are limited to a small number and the patterns directed toward the base station device 101 are not limited. In one example, the reflection patterns of the reflector can be grouped for each reflection pattern directed toward the terminal device. And a group having a characteristic such that a peak of the gain is obtained in the direction toward the area where the radio quality is to be improved by the reflector is specified among the reflection patterns directed toward the terminal device. Then, the base station device 101 transmits information indicating the specified group to the control device. The base station device 101 can then notify the control device of pattern information indicating which reflection pattern among the group should be used. Note that due to a change or addition of the area where the radio quality is to be improved, etc., the base station device 101 can update the group and notify the control device of the information of the updated group.

[0041] As described above, when viewed from the reflector, the reflection patterns in which the direction of the base station device is common may be classified into one group, or the reflection patterns in which the direction of the terminal device is common may be classified into one group. Also, as described above, a group is specified based on the direction of the base station device viewed from the reflector, and among the reflection patterns within the group, the reflection pattern in the direction of the terminal device facing the area where the radio quality is to be improved may be specified as a configurable reflection pattern. Thereby, as long as there is no change in the group of reflection patterns, the base station device 101 can notify the pattern information with the number of bits corresponding to the number of reflection patterns within the group.

[0042] Note that the reflection pattern is realized using a codebook in which the set value of the reflection phase for each reflection element is specified. An index is assigned to the codebook, and as pattern information, the index corresponding to the codebook that realizes a specific reflection pattern is notified. In the above example, the codebooks of the reflection patterns in which the direction of the base station apparatus 101 is common when viewed from the reflector are grouped. Alternatively, the codebooks of the reflection patterns in which the direction of the terminal apparatus is common when viewed from the reflector are grouped. Then, a group index is assigned to the group of codebooks, and a codebook index is assigned to the codebooks within the group. First, the base station apparatus 101 notifies the control apparatus of the group index, and then notifies the control apparatus of the codebook index for specifying the codebook within the group. For example, assume that there are 64 incident patterns (reflection patterns directed toward the base station apparatus 101) and 64 emission patterns (reflection patterns directed toward the terminal apparatus) when the signal transmitted by the base station apparatus 101 is reflected. Here, as an example, the codebooks of the reflection patterns with a common incident pattern are 64 codebooks corresponding to different emission patterns. Such 64 codebooks are treated as a group. Also, since there are 64 incident patterns, there are 64 groups. In another example, the codebooks of the reflection patterns with a common emission pattern are 64 codebooks corresponding to different incident patterns. Such 64 codebooks are treated as a group. Also, since there are 64 emission patterns, there are 64 groups.

[0043] In this way, the reflection patterns are grouped, and information for specifying the group and information for specifying the reflection patterns within the group are transmitted and received separately. Here, by pre-determining the groups so that changes in the groups are less likely to occur, it becomes possible to efficiently control the reflection patterns. Note that the criteria for grouping are not limited to the two examples described above. That is, grouping may be performed based on any criteria. Also, grouping is not necessarily performed. At least, a part of the reflection patterns may be selected, and information for designating that part may be notified from the base station apparatus 101 to the control apparatus. Thereafter, the base station apparatus 101 may notify the control apparatus of pattern information for designating the reflection patterns to be actually used from among the selected part of the reflection patterns. Even with such a configuration, by selecting some of the reflection patterns and limiting the target reflection patterns to be specified as subsequent pattern information, it becomes possible to suppress the data amount of the pattern information. Also, the grouping may be predefined in the network, for example. In this case, the base station apparatus 101 may acquire the information of the pre-defined groups and notify the control apparatus of that information. That is, the base station apparatus 101 may determine the groups, or an apparatus other than the base station apparatus 101 may determine the groups.

[0044] Note that information on a group of reflection patterns and pattern information specifying the reflection pattern actually used within the group can be notified from the base station apparatus 101 to the control apparatus by using, for example, the system information or individual signaling of the cellular communication system as in the above-described embodiment. However, this is merely an example, and for example, the communication between the base station apparatus 101 and the control apparatus may be performed using a wireless communication system other than the cellular communication system. Also, even when information exchange is performed by wired communication between the base station apparatus 101 and the control apparatus, by reducing the amount of pattern information by using grouping, it becomes possible to transmit and receive pattern information quickly and efficiently. Further, for example, group information may be transmitted using a wired communication system or a wireless communication system other than the cellular communication system, and pattern information specifying the reflection pattern used within the group may be transmitted and received using the cellular communication system. Also, group information may be transmitted and received using the cellular communication system, and pattern information may be transmitted and received using another system such as a wired communication system. Also, group information may be transmitted and received using system information as in Embodiment 1, and pattern information may be transmitted and received using individual signaling as in Embodiment 2. Also, group information may be transmitted and received by individual signaling, and pattern information may be transmitted and received using system information. Thus, the medium through which the group information and the pattern information are transmitted can be arbitrarily selected.

[0045] (Device Configuration) Next, a configuration example of the base station device 101, the control device 104, and the control device 107 as described above will be described. Note that the base station device 101 is referred to as the base station device without using reference numerals, and the control device 104 and the control device 107 are collectively referred to as the control device. Hereinafter, FIG. 2 is a diagram showing a hardware configuration example of the base station device and the control device. The base station device and the control device are configured to include, for example, a processor 201, a ROM 202, a RAM 203, a storage device 204, and a communication circuit 205 in one example. The processor 201 is a computer including one or more processing circuits such as a general-purpose CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit), and reads and executes programs stored in the ROM 202 and the storage device 204 to execute the overall processing of the device and each of the above-described processes. The ROM 202 is a read-only memory that stores information such as programs and various parameters related to the processes executed by the base station device and the control device. The RAM 203 functions as a workspace when the processor 201 executes a program, and is a random access memory that stores temporary information. The storage device 204 is configured by, for example, a removable external storage device or the like. The communication circuit 205 includes, for example, circuits for wired or wireless communication of the base station device and the control device. For example, the base station device may be configured to include a circuit for wireless communication such as LTE or 5G for communication with the terminal device 102 or the terminal device 105. Note that the base station device can communicate with the control device using, for example, the communication circuit 205 for LTE or 5G. However, this is just an example, and the base station device may be configured to communicate with the control device using a communication circuit 205 for wired or wireless communication prepared separately from the communication circuit 205 for LTE or 5G. The control device has a communication circuit 205 for wireless or wired communication for communicating with the base station device. In addition, the control device may further have a communication circuit 205 for communication with the reflector (for example, wired). Note that in FIG. 2, one communication circuit 205 is illustrated, but the base station device and the control device may have a plurality of communication circuits. Note that a plurality of communication functions may be implemented by one communication circuit 205.

[0046] FIG. 3 is a diagram showing a functional configuration example of a base station apparatus. As its functions, the base station apparatus includes, for example, a control target determination unit 301, a reflection pattern determination unit 302, a timing determination unit 303, a group selection unit 304, and a setting information notification unit 305. These functional units can be realized, for example, by the processor 201 executing programs stored in the ROM 202 and the storage device 204 and controlling the communication circuit 205 as necessary. However, it is not limited thereto, and for example, dedicated hardware for realizing each function may be prepared.

[0047] The control target determination unit 301 determines a reflector to be the target for setting the reflection pattern among one or more reflectors each controlled by one or more control devices capable of communicating with the base station apparatus. The reflection pattern determination unit 302 determines the reflection pattern to be set for the reflector determined by the control target determination unit 301. The timing determination unit 303 determines the timing at which the set reflection pattern determined by the reflection pattern determination unit 302 should be set for the reflector determined by the control target determination unit 301. Note that the timing determination unit 303 can, for example, determine the timing when the reflection pattern is switched at high speed or frequently, and not determine the timing in other cases. Also, the base station apparatus may not have the timing determination unit 303, for example, when the timing is not specified.

[0048] The group selection unit 304 selects one or some of the groups to be notified to the reflector when, for example, all the reflection patterns that can be set by the reflector are grouped. Note that the group selection unit 304 can select a group that limits the reflection patterns related to the radio wave propagation between the reflector and the base station apparatus based on the positional relationship between the reflector and the base station apparatus. In one example, the reflector measures the radio wave transmitted from the base station apparatus, and based on the measurement result, one or a small number (only a part) of the reflection directions related to the radio wave propagation between the reflector and the base station apparatus are selected, and the reflection pattern including the reflection direction is selected. Alternatively or in addition to this, the group selection unit 304 can select a group that limits the reflection patterns related to the radio wave propagation between the reflector and the terminal device based on the positional relationship between the reflector and the terminal device. In one example, the reflector measures the radio wave transmitted from the terminal device, or the base station apparatus measures the radio wave transmitted from the terminal device and reflected by the reflector while the reflector switches the reflection pattern, and based on the measurement result, one or a small number (only a part) of the reflection directions related to the radio wave propagation between the reflector and the terminal device are selected, and the reflection pattern including the reflection direction is selected. Note that the group selection unit 304 may group all the reflection patterns that can be set by the reflector. The grouping may be performed for each reflection direction related to the radio wave propagation between the reflector and the base station apparatus, or may be performed for each reflection direction related to the radio wave propagation between the reflector and the terminal device. Also, the grouping may be performed based on other criteria. Note that the grouping of the reflection patterns may not be performed, and in that case, the group selection unit 304 may be omitted. On the other hand, when the grouping is performed, the reflection pattern determination unit 302 can select the reflection pattern to be set by the reflector from among the reflection patterns belonging to the group selected by the group selection unit 304. Note that in this case, it may not be possible to obtain sufficient radio quality in the base station apparatus or the terminal device with any of the reflection patterns that can be selected by the reflection pattern determination unit 302. In this case, the group selection unit 304 can execute re-selection of the group.

[0049] The setting information notification unit 305 notifies the control device corresponding to the reflector to be controlled of the setting information indicating the reflection pattern determined by the reflection pattern determination unit 302. When a group is selected by the group selection unit 304, the setting information notification unit 305 notifies the control device of group information that can identify the selected group prior to transmitting the setting information indicating the reflection pattern to be actually used. The setting information notification unit 305 notifies the control device of the setting information (and group information as necessary) indicating the reflection pattern by broadcast transmission or individual signaling. Since this notification method is as described above, it will not be repeated here. Also, the setting information notification unit 305 can set the frequency of transmitting the setting information according to, for example, the frequency of changing the setting of the reflection pattern. For example, when the setting of the reflection pattern is changed frequently, the setting information notification unit 305 can transmit the setting information frequently. According to this, it becomes possible to perform the setting of the reflection pattern in a timely manner.

[0050] FIG. 4 is a diagram showing a functional configuration example of the control device. As its functions, the control device has, for example, a setting information reception unit 401, a reflection pattern control unit 402, and a timing control unit 403. These functional units can be realized, for example, when the processor 201 executes programs stored in the ROM 202 and the storage device 204 and controls the communication circuit 205 as necessary. However, it is not limited to this. For example, dedicated hardware for realizing each function may be prepared.

[0051] The setting information receiving unit 401 receives setting information regarding the reflection pattern of the reflector from the base station device. The setting information includes, for example, pattern information that specifies the setting pattern to be set on the reflector. The reflection pattern control unit 402 sets the reflection pattern of the reflector connected to its own device based on the pattern information. Note that the setting information receiving unit 401 may previously acquire, for example, group information that specifies a part of the reflection patterns that can be set on the reflector. In this case, the setting information receiving unit 401 sets the interpretation of the setting information to be received later based on the group information. That is, when the group information and the setting information are transmitted and received separately, even if the values of the same setting information are the same, the reflection patterns to be set will be different if the groups are different. Therefore, when the setting information receiving unit 401 receives the group information, it can update, for example, a table that associates the setting information with the reflection pattern so as to accurately identify the reflection pattern corresponding to the subsequent setting information. The setting information receiving unit 401 can further receive, as the setting information, information on the timing for setting the reflection pattern. In this case, the timing control unit 403 outputs an instruction on the change timing of the reflection pattern to the reflection pattern control unit 402 based on the timing information. The reflection pattern control unit 402 performs control so that the reflection pattern indicated by the setting information is set on the reflector at an appropriate timing based on the instruction.

[0052] In addition, when the setting information reception unit 401 receives system information that includes setting information and is broadcast, it receives identification information for identifying a reflector from among the setting information. Then, when the setting information reception unit 401 receives setting information that includes identification information corresponding to a reflector connected to the own device, it acquires the information on the reflection pattern included in the setting information. Then, the reflection pattern control unit 402 sets the reflection pattern of the reflector based on the information on the reflection pattern. Note that the setting information reception unit 401 may receive setting information, for example, by individual signaling. The setting information reception unit 401 can establish a connection with a base station device, for example, and receive setting information using the established connection. Also, the setting information reception unit 401 may be configured to receive setting information by individual signaling without establishing a connection using, for example, predetermined setting information that is broadcast. In one example, the setting information reception unit 401 can acquire information on an RNTI that is broadcast and acquire setting information transmitted by DCI using the RNTI. Also, the setting information reception unit 401 may receive in advance information indicating whether the setting information is broadcast or individually signaled. This information can be broadcast from a base station device.

[0053] (Flow of processing) Subsequently, an example of the flow of processing executed in a wireless communication system will be described. Note that since the details of the processing are as described above, here the outline of the flow of processing will be shown and the details will not be repeated.

[0054] FIG. 5 shows an example of the processing flow when the setting information of the reflection pattern is broadcast transmitted. First, the base station device determines a reflector to be controlled for the reflection pattern (S501). Further, the base station device determines a reflection pattern to be set on the reflector (S502). Then, the base station device broadcasts and transmits setting information including information obtained by combining the identification information corresponding to the reflector to be controlled determined in S501 and the pattern information indicating the reflection pattern determined in S502 (S503). The control device monitors the broadcast transmitted setting information and identifies the identification information included in the setting information. Then, the control device determines whether or not the identification information of the reflector connected to the own device and controlled by the own device has been received (S504). Then, when the control device receives the setting information including the identification information of the reflector connected to the own device, the control device refers to the reflection pattern information associated with the identification information in the setting information and identifies the reflection pattern to be set (S505). Then, the control device sets the reflector using the identified reflection pattern (S506). In this way, it becomes possible to control the reflection pattern of the reflector by broadcast transmission.

[0055] FIG. 6 shows an example of the processing flow when the setting information of the reflection pattern is transmitted by individual signaling. Note that, for the processing similar to that in FIG. 5, the same reference numerals are given and the description thereof is omitted. The base station device establishes a connection with the control device responsible for controlling the reflector determined in S501 (S601). Then, the base station device transmits, by individual signaling, the setting information including the pattern information indicating the reflection pattern determined in S502 to the control device (S602). Thereafter, the control device specifies and sets the reflection pattern of the reflector based on the setting information received by individual signaling (S505, S506). In this way, it becomes possible to control the reflection pattern of the reflector by individual signaling.

[0056] In addition, when using individual signaling, connection establishment may not be performed. That is, if the control device can establish downlink synchronization and further decode downlink control information, connection establishment does not necessarily have to be performed. For this reason, for example, information for enabling decoding of downlink control information is broadcast-transmitted, and control information can be transmitted by individual signaling that can be decoded by that information. FIG. 7 shows an example of such a processing flow. For example, the base station device broadcast-transmits an RNTI for enabling decoding of DCI (S701). Then, the base station device transmits information on the reflection pattern to the control device by individual signaling using DCI that can be decoded using the RNTI transmitted in S701 (S702).

[0057] FIG. 8 shows an example of a processing flow when the reflection patterns are grouped and information indicating the group and information indicating the reflection patterns within the group are notified to the control device. In this processing, in the base station device, for the reflector determined as the processing target in S501, a group of reflection patterns is determined (S801), and information indicating the group of reflection patterns is notified to the control device (S802). Then, based on the information indicating the group, the control device makes a setting for specifying the reflection pattern using subsequent setting information with a small number of bits (S803). For example, the control device can make a setting for using a table associating the subsequently transmitted setting information with the reflection pattern based on the information indicating the group. Thereafter, the base station device determines a reflection pattern to be applied to the reflector set by the control device from among the reflection patterns included in the group determined in S801 (S804). Then, the base station device transmits information indicating the reflection pattern to the control device (S805). The control device specifies the reflection pattern from among the groups set in S803 based on the information indicating the reflection pattern (S806), and sets the reflection pattern on the reflector (S807).

[0058] Note that the reflection patterns are pre-grouped, and the base station device can determine which group to use in S801. Also, the control device can also pre-hold information for setting the reflection patterns included in each of the plurality of groups on the reflector. Then, when the control device receives the information specifying the group in S802, it can search for the information for setting the reflection patterns included in that group and perform the setting in S803. The group of reflection patterns includes, for example, reflection patterns that are less than or equal to half the number of reflection patterns that can be set on the reflector. Thereby, it is possible to reduce the number of bits for specifying the reflection patterns within the group by at least 1 bit. In one example, when the reflection patterns that can be set on the reflector are classified into 64 groups, the number of reflection patterns belonging to one group can be reduced to 1 / 64. According to this, the number of bits for specifying the reflection patterns within the group can be reduced by 6 bits.

[0059] As described above, by transmitting the setting information from the base station device to the control device of the reflector in various forms, the reflection pattern on the reflector can be appropriately set. Therefore, it becomes possible to contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, "Build resilient infrastructure, promote sustainable industrialization, and foster innovation."

[0060] The invention is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the gist of the invention.

Claims

1. A base station apparatus having transmission means for transmitting a signal, wherein the transmission means transmits group information identifying a group of reflection patterns, which is a part of a plurality of reflection patterns that can be set by one or more reflectors, for radio waves transmitted and received between the base station apparatus and a terminal apparatus by the one or more reflectors, to a control device corresponding to each of the one or more reflectors, and after transmitting the group information, transmits pattern information identifying a reflection pattern to be set in the reflector, which is a reflection pattern that can be specified from among the group of reflection patterns specified by the group information, to the control device. A base station apparatus characterized by the above.

2. The base station apparatus according to claim 1, further comprising determination means for determining the group.

3. The base station apparatus according to claim 1, wherein the group is a group of reflection patterns in which the direction directed to the base station apparatus is partially limited among the plurality of reflection patterns.

4. The base station apparatus according to claim 1, wherein the group is a group of reflection patterns in which the direction directed to the terminal apparatus is partially limited among the plurality of reflection patterns.

5. A control device for controlling a reflection pattern of a predetermined reflector, having receiving means for receiving a signal from the base station apparatus, and control means for controlling the reflection pattern of the predetermined reflector based on the signal received from the base station apparatus, and having wherein the receiving means receives, from the base station apparatus, group information identifying a group of reflection patterns, which is a part of a plurality of reflection patterns that can be set by the reflector for radio waves transmitted and received between the base station apparatus and a terminal apparatus by the predetermined reflector, After receiving the group information, pattern information capable of specifying a reflection pattern to be set on the predetermined reflector among the groups of reflection patterns specified by the group information is received from the base station apparatus. The control means controls the predetermined reflector to reflect radio waves in the reflection pattern indicated by the pattern information. A control device characterized by the above.

6. The group is a group of reflection patterns in which the direction toward the base station apparatus is partially limited among the plurality of reflection patterns. The control device according to claim 5, characterized by this.

7. The group is a group of reflection patterns in which the direction toward the terminal device is partially limited among the plurality of reflection patterns. The control device according to claim 5, characterized by this.

8. A control method executed by a base station apparatus, transmitting group information that specifies a group of reflection patterns that are part of a plurality of reflection patterns that can be set by the reflector for radio waves transmitted and received between the base station apparatus and a terminal device by one or more reflectors, to each control device corresponding to the one or more reflectors; after transmitting the group information, transmitting pattern information capable of specifying a reflection pattern to be set on the reflector among the groups of reflection patterns specified by the group information, to the control device; A control method characterized by including the above.

9. A control method executed by a control device that controls the reflection pattern of a predetermined reflector, receiving group information that specifies a group of reflection patterns that are part of a plurality of reflection patterns that can be set by the reflector for radio waves transmitted and received between the base station apparatus and a terminal device by the predetermined reflector, from the base station apparatus; After receiving the group information, receiving, from the base station apparatus, pattern information capable of specifying a reflection pattern to be set on the predetermined reflector among the groups of reflection patterns specified by the group information. Controlling the predetermined reflector to reflect radio waves in the reflection pattern indicated by the pattern information. A control method characterized by including the above.

10. Causing a computer provided in a base station apparatus to transmit group information specifying a group of reflection patterns, which is a part of a plurality of reflection patterns that can be set by the reflector for radio waves transmitted and received between the base station apparatus and a terminal apparatus by one or more reflectors, to a control device corresponding to each of the one or more reflectors. After transmitting the group information, causing the control device to receive pattern information capable of specifying a reflection pattern to be set on the reflector among the groups of reflection patterns specified by the group information. A program for the above.

11. Causing a computer provided in a control device that controls a reflection pattern of a predetermined reflector to receive, from the base station apparatus, group information specifying a group of reflection patterns, which is a part of a plurality of reflection patterns that can be set by the reflector for radio waves transmitted and received between the base station apparatus and a terminal apparatus by the predetermined reflector. After receiving the group information, causing the control device to receive, from the base station apparatus, pattern information capable of specifying a reflection pattern to be set on the predetermined reflector among the groups of reflection patterns specified by the group information. Causing the predetermined reflector to be controlled to reflect radio waves in the reflection pattern indicated by the pattern information. A program for the above.

Images