Base station, communication terminal, base station communication method, communication terminal communication method, base station communication program, and communication terminal communication program

Abstract

To more efficiently search for a communication terminal.SOLUTION: A base station includes: an antenna that emits a search radio beam for searching for a communication terminal and a communication radio beam for communicating with a communication terminal; and a control unit that executes transmission processing of simultaneously transmitting a plurality of search radio beams with different directions from the antenna, reception processing of receiving radio waves transmitted from the communication terminal in response to the plurality of search radio beams which are simultaneously transmitted in the transmission processing, and communication processing of communicating using the communication radio beam with the communication terminal that has transmitted the radio waves received in the reception processing.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a base station, a communication terminal, a communication method for a base station, a communication method for a communication terminal, a communication program for a base station, and a communication program for a communication terminal. [Background technology]

[0002] 2. Description of the Related Art There are known communication systems in which communication is performed between a base station and a communication terminal. One example of such a communication system is a wireless communication system described in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-121190 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the wireless communication system described in Patent Document 1, the base station forms a beam directed toward the terminal, thereby performing communication between the base station and the terminal.

[0005] However, in order to identify a terminal that communicates with a base station, the base station needs to search for the terminal, for example, by scanning a beam, which creates a waiting time until the terminal receives the beam, and it takes time to search for the terminal.

[0006] The present disclosure has been made in consideration of the above problems, and one exemplary objective thereof is to provide a base station, a communication terminal, a communication method for a base station, a communication method for a communication terminal, a communication program for a base station, and a communication program for a communication terminal that improve the efficiency of searching for communication terminals. [Means for solving the problem]

[0007] A base station according to an exemplary aspect of the present disclosure is a base station for a communication terminal, and is equipped with an antenna that emits a search radio wave beam for searching for a communication terminal and a communication radio wave beam for communicating with the communication terminal, and a control unit, wherein the control unit executes a transmission process that simultaneously transmits from the antenna a plurality of search radio wave beams facing in different directions, a reception process that receives radio waves transmitted from the communication terminal corresponding to the plurality of search radio wave beams transmitted simultaneously by the transmission process, and a communication process that uses the communication radio wave beam to communicate with the communication terminal that transmitted the radio waves received by the reception process.

[0008] A communication method of a base station according to an exemplary aspect of the present disclosure includes a transmission process of transmitting multiple search radio wave beams from an antenna, the multiple search radio wave beams facing different directions from each other, a reception process of receiving radio waves transmitted from a communication terminal corresponding to the multiple search radio wave beams transmitted by the transmission process, and a communication process of communicating with the communication terminal that transmitted the radio waves received by the reception process using the communication radio wave beam. Effect of the Invention

[0009] According to an exemplary aspect of the present disclosure, an exemplary effect is achieved in that the efficiency of searching for communication terminals can be improved. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a configuration of a communication system according to the present disclosure. [Diagram 2] 1 is a flow diagram showing the flow of a communication method in a communication system according to the present disclosure. [Diagram 3] 1 is a block diagram showing a configuration of a communication system according to the present disclosure. [Figure 4] 1 is a flow diagram showing the flow of a communication method in a communication system according to the present disclosure. [Diagram 5] FIG. 2 is a schematic diagram showing beam distribution according to the present disclosure. [Figure 6] FIG. 2 is a schematic diagram showing beam distribution according to the present disclosure. [Figure 7]FIG. 2 is a schematic diagram showing beam distribution according to the present disclosure. [Figure 8] 1 is a block diagram showing a configuration of a computer that functions as a control unit of a base station or a communication terminal according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The following are examples of embodiments of the present invention. However, the present invention is not limited to the exemplary embodiments shown below, and various modifications are possible within the scope of the claims. For example, an embodiment obtained by appropriately combining the technical means employed in each of the exemplary embodiments shown below may also be included in the scope of the present invention. In addition, an embodiment obtained by appropriately omitting a part of the technical means employed in each of the exemplary embodiments shown below may also be included in the scope of the present invention. In addition, the effects mentioned in each of the exemplary embodiments shown below are examples of effects expected in the exemplary embodiments, and do not define the scope of the present invention. In other words, an embodiment that does not exhibit the effects mentioned in each of the exemplary embodiments shown below may also be included in the scope of the present invention.

[0012] First Exemplary Embodiment A first exemplary embodiment, which is an example of an embodiment of the present invention, will be described in detail with reference to the drawings. This exemplary embodiment is the basic form of each exemplary embodiment described later. The scope of application of each technical means adopted in this exemplary embodiment is not limited to this exemplary embodiment. That is, each technical means adopted in this exemplary embodiment can be adopted in other exemplary embodiments included in this disclosure to the extent that no particular technical obstacle occurs. In addition, each technical means shown in the drawings referred to for explaining this exemplary embodiment can also be adopted in other exemplary embodiments included in this disclosure to the extent that no particular technical obstacle occurs.

[0013] (Communication System Configuration) The configuration of the communication system 1 will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the configuration of the communication system 1. As shown in Fig. 1, the communication system 1 includes a base station 10 and at least one communication terminal 20(i).

[0014] (Base station configuration) The base station 10 is a base station for at least one communication terminal 20(i), and includes an antenna 11, a transmission / reception unit 12, and a control unit 13. The antenna 11 is driven by the transmission / reception unit 12 to radiate (transmit) a search radio beam B1 and a communication radio beam B2, and receives radio waves from the communication terminal 20(i). The search radio beam B1 is a radio beam for searching for the communication terminal 20(i). The communication radio beam B2 is a radio beam for communicating with the communication terminal 20(i).

[0015] The control unit 13 executes a transmission process S11a, a reception process S12a, and a communication process S13a, as shown in a communication method S1a described later. The transmission process S11a is a process of simultaneously transmitting a plurality of searching radio wave beams B1 facing different directions from the antenna 11. The reception process S12a is a process of receiving radio waves transmitted (transmission process S12b) from the communication terminal 200(i) in response to the plurality of searching radio wave beams B1 transmitted simultaneously by the transmission process S11a. The communication process S13a is a process of communicating with the communication terminal 20(i) that transmitted the radio waves received by the reception process S12a (transmission process S12b) by using the communication radio wave beam B2.

[0016] (Configuration of communication terminal) The communication terminal 20(i) is a communication terminal that communicates with the base station 10, and includes an antenna 21, a transceiver unit 22, and a control unit 23. The antenna 21 is driven by the transceiver unit 22 to receive a search radio beam B1 and a communication radio beam B2, and transmit radio waves. The communication terminal 20(i) can communicate with the base station 10 by the communication radio beam B2 from the base station 10 and radio waves from the communication terminal 20(i). The control unit 23 executes a communication method S1b, which will be described later.

[0017] (Flow of communication method in communication system 1) The flow of the communication method S1 in the communication system 1 will be described with reference to Fig. 2. Fig. 2 is a flow diagram showing the flow of the communication method S1. As shown in Fig. 2, the communication method S1 can be divided into a communication method S1a of the base station 10 and a communication method S1b of the communication terminal 20(i).

[0018] The communication method S1a of the base station 10 includes a transmission process S11a, a reception process S12a, and a communication process S13a. The transmission process S11a is a process of transmitting a plurality of searching radio wave beams facing different directions from an antenna. The reception process S12a is a process of receiving radio waves transmitted from the communication terminal 20(i) corresponding to the plurality of searching radio wave beams B1 transmitted by the transmission process S11a. The communication process S13a is a process of communicating with the communication terminal 20(i) that transmitted the radio wave received by the reception process S12a, using the communication radio wave beam B2. The communication method S1b of the communication terminal 20(i) includes a reception process S11b, a transmission process S12b, and a communication process S13b. These communication methods S1a and S1b are executed as follows.

[0019] (1) Transmission of a searching radio beam B1 from the base station 10 (transmission process S11a) The control unit 13 of the base station 10 controls the transmitting / receiving unit 12 to execute a transmission process for simultaneously transmitting from the antenna 11 a plurality of searching radio beams B1 pointing in different directions.

[0020] (2) Reception of the searching radio beam B1 by the communication terminal 20(i) (reception process S11b) The control unit 23 of the communication terminal 20(i) executes a reception process for receiving, via the antenna 21, any one of a plurality of searching radio beams B1 transmitted from the base station 10 and directed in different directions.

[0021] (3) Transmission of radio waves from communication terminal 20(i) (transmission process S12b) The control unit 23 of the communication terminal 20(i) executes a transmission process for transmitting radio waves from the antenna 21 in response to the searching radio wave beam B1 transmitted from the base station 10.

[0022] (4) Reception of radio waves by the base station 10 (reception process S12a) The control unit 13 of the base station 10 executes a receiving process to receive radio waves transmitted from the communication terminal 20(i) in response to the multiple searching radio beams B1 transmitted simultaneously by the transmission process S11a. As a result, the control unit 13 of the base station 10 determines that the communication terminal 20(i) has received the searching radio beam B1, and is able to start communication with the communication terminal 20(i).

[0023] (5) Communication between base station 10 and communication terminal 20(i) (communication processes S13a and S13b) The control unit 13 of the base station 10 executes a communication process to communicate with the communication terminal 20(i) that transmitted the radio wave received in the reception process S12a, using the communication radio wave beam B2. Meanwhile, the control unit 23 of the communication terminal 20(i) executes a communication process to communicate with the base station 10, using the radio wave beam transmitted in the transmission process S12b.

[0024] Here, communication terminal 20(i) can communicate with base station 10 using radio waves that have substantially no directionality. On the other hand, when antenna 21 of communication terminal 20(i) can transmit a radio wave beam having directionality, communication terminal 20(i) may communicate with base station 10 using radio waves having directionality (i.e., a radio wave beam).

[0025] (Effect of base station) As described above, the base station 10 executes a transmission process for simultaneously transmitting a plurality of searching radio beams facing different directions from the antenna 11. Therefore, the base station 10 can search for the communication terminal 20(i) more efficiently than when scanning a single searching radio beam B1.

[0026] (Effect of base station communication method) As described above, the communication method S1a employs a transmission processing configuration in which a plurality of searching radio beams facing different directions are simultaneously transmitted from the antenna 11. Therefore, according to the base station communication method S1a, it is possible to search for the communication terminal 20(i) more efficiently than when scanning a single searching radio beam B1.

[0027] Second Exemplary Embodiment A second exemplary embodiment, which is an example of an embodiment of the present invention, will be described in detail with reference to the drawings. Components having the same functions as those described in the above exemplary embodiment will be given the same reference numerals, and their description will be omitted as appropriate. The scope of application of each technical means adopted in this exemplary embodiment is not limited to this exemplary embodiment. That is, each technical means adopted in this exemplary embodiment can be adopted in other exemplary embodiments included in this disclosure, as long as no particular technical hindrance occurs. In addition, each technical means shown in each drawing referred to for explaining this exemplary embodiment can be adopted in other exemplary embodiments included in this disclosure, as long as no particular technical hindrance occurs.

[0028] (Communication System Configuration) The configuration of the communication system 2 will be described with reference to Fig. 3. Fig. 3 is a block diagram showing the configuration of the communication system 2. As shown in Fig. 1, the communication system 2 includes a base station 100 and at least one communication terminal 200(i).

[0029] (Base station configuration) The base station 100 is a base station for the communication terminal 200(i) and includes an antenna 101, a transmission / reception unit 102, a control unit 103, a storage unit 104, and an input / output unit 105. The antenna 101 is driven by the transmission / reception unit 102 to emit a search radio beam B1 and a communication radio beam B2. The search radio beam B1 is a radio beam for searching the communication terminal 200(i). The communication radio beam B2 is a radio beam for communicating with the communication terminal 200(i). The control unit 103 executes a communication method S10a described later. The storage unit 104 stores a table Ta. It is preferable that the table Ta indicates at least one of the number of multiple search radio beams B1, the type of the antenna 101, and the radio wave interference state, in correspondence with the frequency and transmission direction of the multiple search radio beams. The interference state of radio waves means interference between response radio beams transmitted from multiple communication terminals 20(i) to the base station 100 within the width of the searching radio beam B1. As described later, the width and radiation direction of the searching radio beam B1 can be adjusted according to the interference state of radio waves from the multiple communication terminals 20(i). The input / output unit 105 is a device for the administrator of the base station 100 to input and output information, such as a keyboard, display device, or touch display, and can be used to input and output transmission and reception conditions of the base station 100.

[0030] (Configuration of communication terminal) The communication terminal 200(i) is a communication terminal that communicates with the base station 100, and includes an antenna 201, a transmission / reception unit 202, a control unit 203, and a storage unit 204. The antenna 201 is driven by the transmission / reception unit 202 to transmit and receive radio waves. The communication radio wave beam B2 is a radio wave beam for communicating with the communication terminal 200(i). The control unit 203 executes a communication method S10b, which will be described later, including a reception process S111b, an extraction process S112b, a transmission process S113b, and a communication process S121b. The reception process S111b is a process of receiving, via the antenna 201, any one of a plurality of search radio wave beams B1 that are directed in different directions and transmitted from the base station 100. The extraction process S112b is a process of extracting direction identification information that identifies the direction of the base station 100 from the search radio wave beam B1 received in the reception process S111b. The transmission process S113b is a process of transmitting a radio wave beam toward the base station 100 based on the direction identification information extracted in the extraction process S112b. The communication process S121b is a process of communicating with the base station 100 using the radio wave beam transmitted in the transmission process S113b. The storage unit 204 stores a table Tb. The table Tb indicates the correspondence between the direction identification information included in the searching radio beam B1 that identifies the direction of the base station and the direction of the base station 100.

[0031] (Flow of communication method in communication system 2) The flow of the communication method S1 in the communication system 1 will be described with reference to Fig. 4. Fig. 4 is a flow diagram showing the flow of the communication method S10. As shown in Fig. 4, the communication method S10 can be divided into a communication method S10a in the base station 100 and a communication method S10b in the communication terminal 200(i). The communication method S10a includes an acquisition process S101a, a setting process S102a, a transmission process S111a, a reception process S113a, and a communication process S121a. The communication method S10b includes a reception process S111b, an extraction process S112b, a transmission process S113b, and a communication process S121b. These communication methods S10a and S10b are executed as follows.

[0032] A. Acquisition of transmission and reception conditions of the base station 100 (acquisition process S101a) The control unit 103 of the base station 100 executes an acquisition process to acquire the transmission and reception conditions of the base station 100. The transmission and reception conditions include at least any of information on the number of multiple searching radio beams B1, the type of antenna (including performance), and the interference state of radio waves. These conditions may be acquired by the control unit 103 from the transmission and reception unit 102 or the like, or may be input by the administrator from the input / output unit 105.

[0033] B. Setting of conditions in base station 100 (setting process S102a) The control unit 103 of the base station 100 sets the pattern of the searching radio beam B1 to be transmitted in the transmission process S111a based on the table Ta.

[0034] Basically, the control unit 103 can set the frequencies and transmission directions of a plurality of searching radio beams B1 based on the table Ta. For example, the table Ta indicates the frequencies and transmission directions of a plurality of searching radio beams B1 in correspondence with each other. The control unit 103 can set the frequencies and transmission directions of a plurality of searching radio beams B1 based on this table Ta and transmit the beams.

[0035] At this time, the control unit 103 can set the frequencies and transmission directions of the multiple searching radio beams B1 based on the acquired transmission and reception conditions (the number of multiple searching radio beams B1, the type of antenna, and the state of radio wave interference). For example, the table Ta represents the transmission and reception conditions, the frequencies and transmission directions of the multiple searching radio beams B1 in correspondence with each other. The control unit 103 can set the frequencies and transmission directions of the multiple searching radio beams B1 based on the table Ta and transmit them.

[0036] Fig. 5 to Fig. 7 are schematic diagrams showing the patterns of the searching radio beam B1 set in the setting process S102a. Fig. 5 shows beam patterns BP11 to BP13. Fig. 6 shows beam patterns BP21 and BP22. Fig. 7 shows beam patterns BP31 and BP32.

[0037] The antenna 101 of the base station 100 is disposed at the center C of the beam patterns BP11 to BP13, BP21, BP22, BP31, and BP32. Figs. 5 to 7 show the state in which the searching radio beam B1 is viewed from above the antenna 101. The antenna 101 is driven by the transmitting / receiving unit 102, and can simultaneously radiate a plurality of searching radio beams B1 facing in different directions. The searching radio beams B1 are radiated radially from the antenna 101 toward a circumference CF centered on the center C.

[0038] (1) Beam type (1): The multiple searching radio beams B1 transmitted simultaneously can include a first set of searching radio beams having mutually different frequencies.

[0039] At this time, the first set of multiple searching radio beams B1 may have different frequencies and may include multiple searching radio beams B1 adjacent to each other (beam form (1-1)).

[0040] Beam patterns BP11 to BP13 are examples of beam form (1-1) and represent cases where the number of searching radio beams B1 is 16, 8, and 4. Note that beam patterns BP12 and BP13 are based on the premise that the maximum number of searching radio beams B1 is 16.

[0041] In beam pattern BP11, 16 searching radio beams B1 (beam identifiers P00, P01, ..., P15) are arranged in order in a clockwise direction based on the direction due north (N) from center C. That is, a circumference CF surrounding center C is divided into 16 arcs CA, and searching radio beams B1 with beam identifiers P00 to P15 are assigned to each of the 16 arcs CA. The beam identifiers P00 to P15 are identifiers (beam IDs) that distinguish the searching radio beams B1 from one another.

[0042] Here, the beam identifiers P00 to P15 are associated with the direction (beam direction) in which the searching radio beam B1 is emitted, and are set in ascending order (00 to 15) with the direction of true north (N) as the reference. By associating the beam identifiers P00 to P15 with the beam emission direction, it becomes easy to determine the beam direction from the beam identifier. It is also possible not to associate the beam identifiers P00 to P15 with the direction in which the searching radio beam B1 is emitted.

[0043] Channel identifiers ch00 to ch15 are set corresponding to the beam identifiers P00 to P15. The channel identifiers ch00 to ch15 correspond to the channel of the searching radio beam B1, that is, the frequency of the searching radio beam B1. The numbers (00 to 15) of the channel identifiers ch00 to ch15 correspond to the channel of the searching radio beam B1, that is, the magnitude of the frequency. Here, the frequencies of the searching radio beam B1 are set in ascending order with the direction of true north (N) as the reference. However, the frequencies of the searching radio beam B1 may also be set in descending order. Also, this order may be changed as appropriate.

[0044] Here, the frequencies of the searching radio beams B1 are set in sequence in accordance with the direction in which the searching radio beams B1 are emitted (beam direction). As a result, adjacent searching radio beams B1 have different channels (frequencies). Therefore, even if the communication terminal 200(i) is placed near the boundary between adjacent searching radio beams B1, it is possible to prevent interference between the adjacent searching radio beams B1 from occurring in the communication terminal 200(i).

[0045] In the beam pattern BP11, the searching radio beams B1 of beam identifiers P00 to P15 are adjacent to adjacent searching radio beams B1 of different channels with no gaps between them. In other words, the searching radio beams B1 of identifiers P00 to P15 can search for the communication terminals 200(i) arranged in all directions from the center C without scanning.

[0046] As described above, the beam identifiers P00 to P15, the radiation direction of the searching radio beam B1, and the channel identifiers ch00 to ch15 (i.e., the channel and frequency of the searching radio beam B1) correspond to one another. That is, the beam identifiers can function as beam identification information that identifies multiple searching radio beams B1, direction identification information that identifies the radiation direction of the searching radio beam B1, and frequency identification information that identifies the channel (frequency) of the searching radio beam B1.

[0047] Each of the multiple searching radio beams B1 preferably includes information on a beam identifier and a channel identifier. In this case, it becomes easy for the communication terminal 200(i) to extract beam identification information, direction identification information, and frequency identification information from the received searching radio beam B1.

[0048] It is preferable that the tables Ta and Tb show beam identifiers P00 to P15, the radiation direction of the searching radio beam B1, and the channel identifiers ch00 to ch15 (channel and frequency of the searching radio beam B1) in association with each other. By using the table Ta, the control unit 103 of the base station 100 can easily assign beam identifier information (and channel identifier information, if necessary) to the searching radio beam B1. By using the table Tb, the control unit 203 of the communication terminal 200(i) can easily identify the direction and channel (frequency) of the searching radio beam B1 from the beam identifier information (beam identification information) extracted from the searching radio beam B1.

[0049] In the beam patterns BP12 and BP13, eight and four searching radio beams B1 are used, respectively. In the beam patterns BP12 and BP13, on the premise that the maximum number of searching radio beams B1 is 16, the smallest beam identifier in the beam pattern BP11 is assigned to each searching radio beam B1, as shown below.

[0050] In beam pattern BP12, the circumference CF is divided into eight arcs CA, and every other searching radio beam B1 with beam identifiers P00, P02, P04, P06, ..., P14 is assigned to each of the eight arcs CA (eight searching radio beams B1). In beam pattern BP13, the circumference CF is divided into four arcs CA, and every third searching radio beam B1 with beam identifiers P00, P04, P08, P12 is assigned to each of the four arcs CA (four searching radio beams B1). Note that the unassigned beam identifiers are not used.

[0051] In this way, the width of the searching radio beam B1 may be widened and a wide angle range may be assigned to one searching radio beam B1. This makes it possible to search for the communication terminal 200(i) with a small number of searching radio beams B1.

[0052] Beam pattern BP21 uses six searching radio beams B1 with beam identifiers p00, p02, p04, p08, p10, and p12. The searching radio beams B1 with beam identifiers p00, p02, p08, and p10 correspond to the searching radio beams B1 divided in eight directions of the beam pattern BP12. The searching radio beams B1 with beam identifiers p04 and p12 correspond to the searching radio beams B1 divided in four directions of the beam pattern BP13. In this way, it is also possible to mix searching radio beams B1 with different widths.

[0053] The control unit 103 may change the width of the searching radio beam B1 depending on the type (performance) of the antenna 101 or the interference state of radio waves. For example, in a direction where the interference state of radio waves is relatively good, the width of the searching radio beam B1 can be widened to assign a wide angle range to one searching radio beam B1. On the other hand, in a direction where the interference state of radio waves is relatively bad, it is preferable to narrow the width of the searching radio beam B1 to assign a narrow angle range to one searching radio beam B1.

[0054] In beam pattern BP22, five searching radio beams B1 with beam identifiers p00, p02, p04, p06, and p10 are used. These searching radio beams B1 correspond to the eight-directionally divided searching radio beams B1 of beam pattern BP12. The searching radio beams B1 with beam identifiers p06 and p10 are spaced apart from each other. The searching radio beams B1 with beam identifiers p10 and p00 are spaced apart from each other. In other words, the searching radio beam B1 is not positioned between beam identifiers p06 and p10, and between beam identifiers p10 and p00. In this way, some (or all) of the multiple searching radio beams B1 radiated simultaneously do not have to be adjacent to each other.

[0055] The control unit 103 may set a direction in which the searching radio beam B1 is not radiated depending on the type (performance) of the antenna 101 or the radio wave interference state. For example, if there is a direction in which transmission and reception are not possible due to the characteristics of the antenna 101, the control unit 103 sets the searching radio beam B1 to avoid that direction. Also, if there is a direction in which the radio wave interference state is poor and it is practically impossible to search for the communication terminal 200(i), the control unit 103 may set the searching radio beam B1 to avoid that direction.

[0056] When a direction in which the searching radio beam B1 is not radiated is temporarily set, the searching radio beam B1 may be scanned to enable the radiation of the searching radio beam B1 in all directions. In the beam pattern BP22, the communication terminal 200(i) located between the searching radio beams B1 with beam identifiers p06 and p10 and between the searching radio beams B1 with beam identifiers p10 and p00 is excluded from the search target by the base station 100. However, for example, the searching radio beam B1 with either beam identifier p06 or p10 is scanned. This makes it possible to search for the communication terminal 200(i) located between the beam identifiers p06 and p10. Similarly, the searching radio beam B1 with either beam identifier p10 or p00 is scanned to search for the communication terminal 200(i) located between the beam identifiers p10 and p00. The details of the scanning of the searching radio beam B1 will be described later.

[0057] (2) Beam type (2): The multiple searching radio beams B1 transmitted simultaneously can include a second set of searching radio beams having the same frequency and spaced apart from each other.

[0058] Here, a case is considered where multiple searching radio beams B1 of the same channel are spaced apart. When multiple searching radio beams B1 of the same channel are adjacent to each other (for example, beam pattern BP32 described later), interference may occur in the communication terminal 200(i). In this case, the communication terminal 200(i) located near the boundary of the searching radio beams B1 may simultaneously receive these searching radio beams B1, and the information of the searching radio beams B1 may be mixed (so-called interference). Even if multiple searching radio beams B1 of the same channel are spaced apart, it is possible to prevent the communication terminal 200(i) from simultaneously receiving these searching radio beams B1 and causing interference.

[0059] In this case, in order to search for the communication terminal 200(i) located between a plurality of spaced apart searching radio beams B1, the searching radio beam B1 can be scanned. This scanning can be performed, for example, as follows (a) or (b).

[0060] (a) In the transmission process, the control unit 103 can transmit the second set of searching radio beams while changing the direction of the searching radio beams. This means that the direction of the searching radio beams is changed continuously.

[0061] (b) In the transmission process, the control unit 103 stops the transmission of the second set of searching radio beams, and transmits a third set of searching radio beams that have the same frequency, are spaced apart from each other, and do not overlap in direction with the second set of searching radio beams. This means that the direction of the searching radio beams is intermittently changed.

[0062] As described above, by changing the direction of the searching radio beam B1 over time, it becomes possible to search for the communication terminal 200(i) in all directions using a plurality of searching radio beams B1 of the same channel.

[0063] In beam pattern BP31, by combining two sets of searching radio beams B1 of beam mode (2), scanning of the searching radio beams B1 is not required. In beam pattern BP31, channel identifiers ch00 and ch01 are alternately assigned to beam identifiers p00 to p15. That is, by alternately assigning two channels to adjacent searching radio beams B1, interference between adjacent searching radio beams B1 is prevented, and simultaneous transmission of the searching radio beams B1 in all directions is made possible.

[0064] Here, two channels ch00 and ch01 are alternately allocated, but three or more channels (for example, channels ch00 to ch02) may be allocated in order. Also, the order of channels ch00 to ch02 does not have to be constant. As long as the channels are not the same between adjacent searching radio beams B1, the order of the channels can be changed as appropriate.

[0065] On the other hand, in the beam pattern BP32, the same channel identifier ch00 is assigned to all of the beam identifiers p00 to p15. It is preferable not to use this beam pattern BP22 as the searching radio beam B1.

[0066] (3) Beam mode (3) (mixture of beam modes (1) and (2)): The multiple searching radio beams B1 may include a first set of searching radio beams having different frequencies, and a second set of searching radio beams having the same frequency and spaced apart from each other.

[0067] C. Transmission of a searching radio beam B1 from the base station 100 (transmission process S111a) The control unit 103 of the base station 100 controls the transmitting / receiving unit 102 to execute a transmission process for simultaneously transmitting from the antenna 101 a plurality of searching radio beams B1 pointing in different directions.

[0068] As described above, the control unit 103 of the base station 100 transmits the searching radio beam B1 in a plurality of directions using the beam modes (1), (2), and (3). At this time, the control unit 103 can make the searching radio beam B1 include a beam identifier.

[0069] D. Reception of the searching radio beam B1 by the communication terminal 200(i) (reception process S111b) The control unit 203 of the communication terminal 200(i) executes a reception process for receiving, via the antenna 201, any one of a plurality of searching radio beams B1 transmitted from the base station 100 and directed in different directions.

[0070] E. Extraction of beam-specific information from the searching radio beam B1 by the communication terminal 200(i) (extraction process S112b) The control unit 203 of the communication terminal 200(i) extracts beam identification information from the searching radio beam B1. This extraction is divided into a case where the searching radio beam B1 includes a beam identifier (a) and a case where it does not include a beam identifier (b).

[0071] (a) When the search radio beam B1 includes a beam identifier The control unit 203 of the communication terminal 200(i) extracts a beam identifier from the searching radio beam B1 received by the antenna 201. The beam identifier functions as beam identifying information that identifies the searching radio beam.

[0072] The control unit 203 can specify the frequency (channel) and direction of the searching radio beam B1 by using the table Ta. This method is applicable to both the case of the beam mode (2) (wherein the multiple searching radio beams B1 radiated simultaneously include searching radio beams B1 of the same channel) and the case where the beam mode is not (2).

[0073] (b) When the search radio beam B1 does not include a beam identifier The control unit 203 of the communication terminal 200(i) performs FFT (Fast Fourier Transform) on the searching radio beam B1 received by the antenna 201 to extract information (frequency identification information) on the frequency (channel) of the searching radio beam B1.

[0074] The control unit 203 can specify the direction of the searching radio beam B1 by using the extracted frequency identification information and table Tb (which indicates the frequency identification information and the direction identification information in correspondence with each other). Note that this method is difficult to apply in the case of the beam mode (2) (where multiple searching radio beams B1 radiated simultaneously include searching radio beams B1 of the same channel).

[0075] F. Transmission of radio waves from communication terminal 200(i) (transmission process S113b) The control unit 203 of the communication terminal 200 ( i ) executes a transmission process for transmitting radio waves from the antenna 201 in response to the searching radio beam B 1 transmitted from the base station 100 .

[0076] This transmission is for notifying that communication terminal 200(i) has received searching radio beam B1 from base station 100 and is able to communicate with base station 100. This notification enables base station 100 to determine that the search for communication terminal 200(i) has ended and that communication with the searched communication terminal 200(i) is possible.

[0077] The communication terminal 200(i) can use the channel of the received searching radio beam B1 to notify the base station 100 of the beam identifier with which communication is possible. Note that the communication terminal 200(i) may use the radio wave for notification without changing the frequency from that for communication.

[0078] Here, communication terminal 200(i) can transmit radio waves that have substantially no directivity to base station 100. On the other hand, when antenna 201 of communication terminal 200(i) can transmit a radio wave beam having directivity, communication terminal 200(i) may communicate with base station 100 using radio waves having directionality (i.e., a radio wave beam).

[0079] It is assumed that the searching radio beam B1 transmitted from the base station 100 includes direction identification information for identifying the direction of the base station 100. In this case, the control unit 23 of the communication terminal 20(i) can execute an extraction process S112b for extracting direction identification information for identifying the direction of the base station 100 from the searching radio beam B1 received in the reception process S111b. Then, in a transmission process S113b, the control unit 203 of the communication terminal 200(i) can transmit a radio beam toward the base station 100 based on the direction identification information extracted in the extraction process. Then, a communication process for communicating with the base station 100 can be executed using the radio beam transmitted in this transmission process S113b.

[0080] G. Reception of radio waves by base station 100 (reception process S113a) The control unit 103 of the base station 100 executes a receiving process to receive radio waves transmitted from the communication terminal 200(i) in response to the multiple searching radio wave beams B1 transmitted simultaneously by the transmission process S111a. With this notification, the base station 100 can determine that the search for the communication terminal 200(i) has ended and that communication with the searched communication terminal 200(i) is possible.

[0081] H. Communication between base station 100 and communication terminal 200(i) (communication processes S121a and S121b) The control unit 103 of the base station 100 executes a communication process to communicate with the communication terminal 200(i) that transmitted the radio wave received in the reception process S113a, using the communication radio wave beam B2. Meanwhile, the control unit 203 of the communication terminal 200(i) executes a communication process to communicate with the base station 100, using the radio wave beam transmitted in the transmission process S113b.

[0082] For example, the multiple searching radio beams B1 have different frequencies and directions, and in the reception process S111b, the radio waves received by the communication terminal 200(i) may have beam identification information for identifying the multiple searching radio beams B1. In this case, in the communication process S121b, the control unit 203 may communicate with the base station 100 using a communication radio beam of a frequency and direction corresponding to the frequency and direction of the searching radio beam B1 identified by the beam identification information.

[0083] The base station 100 communicates with the communication terminal 200(i) using the communication radio beam B2. At this time, the base station 100 may communicate with multiple communication terminals 200(i) using one communication radio beam B2. By switching communication with multiple communication terminals 200(i) over time, it is possible to communicate with multiple communication terminals 200(i) in parallel.

[0084] As described above, in the base station 100, by simultaneously transmitting a plurality of searching radio beams pointing in different directions from the antenna, it becomes possible to efficiently search for the communication terminal 200(i).

[0085] [Software implementation example] Some or all of the functions of the base station 100 and the communication terminal 200 (hereinafter also referred to as "the above-mentioned devices") may be realized by hardware such as an integrated circuit (IC chip), or may be realized by software.

[0086] In the latter case, each of the above devices is realized, for example, by a computer that executes instructions of a program, which is software that realizes each function. An example of such a computer (hereinafter, referred to as computer C) is shown in Fig. 8. Fig. 8 is a block diagram showing the hardware configuration of computer C that functions as each of the above devices.

[0087] The computer C includes at least one processor C1 and at least one memory C2. The memory C2 stores a program P for causing the computer C to operate as each of the above-mentioned devices. In the computer C, the processor C1 reads and executes the program P from the memory C2, thereby realizing the functions of each of the above-mentioned devices.

[0088] The processor C1 may be, for example, a central processing unit (CPU), a graphic processing unit (GPU), a digital signal processor (DSP), a micro processing unit (MPU), a floating point number processing unit (FPU), a physics processing unit (PPU), a tensor processing unit (TPU), a quantum processor, a microcontroller, or a combination thereof. The memory C2 may be, for example, a flash memory, a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof.

[0089] The computer C may further include a RAM (Random Access Memory) for expanding the program P during execution and for temporarily storing various data. The computer C may further include a communication interface for transmitting and receiving data to and from other devices. The computer C may further include an input / output interface for connecting input / output devices such as a keyboard, a mouse, a display, and a printer.

[0090] Furthermore, the program P can be recorded on a non-transitory tangible recording medium M that can be read by the computer C. Such a recording medium M can be, for example, a tape, a disk, a card, a semiconductor memory, or a programmable logic circuit. The computer C can obtain the program P via such a recording medium M. Furthermore, the program P can be transmitted via a transmission medium. Such a transmission medium can be, for example, a communication network or broadcast waves. The computer C can also obtain the program P via such a transmission medium.

[0091] [Additional Note 1] This disclosure includes the techniques described in the following appendices. However, the present invention is not limited to the techniques described in the following appendices, and various modifications are possible within the scope of the claims. (Appendix 1) A base station for a communication terminal, an antenna for emitting a search radio beam for searching for a communication terminal and a communication radio beam for communicating with the communication terminal; A control unit, The control unit is a transmission process of simultaneously transmitting a plurality of search radio beams from the antenna, the search radio beams being oriented in different directions; a receiving process for receiving radio waves transmitted from a communication terminal in response to the plurality of searching radio wave beams simultaneously transmitted by the transmitting process; A communication process for communicating with the communication terminal that transmitted the radio wave received in the receiving process by using a radio wave beam for communication; A base station that executes the above.

[0092] (Appendix 2) A base station as described in Appendix 1, wherein the multiple search radio beams include a first set of search radio beams having different frequencies.

[0093] (Appendix 3) The first set of searching radio beams includes a plurality of searching radio beams having different frequencies and adjacent to each other, 3. A base station as defined in claim 2.

[0094] (Appendix 4) The plurality of searching radio beams include a second set of searching radio beams having the same frequency and spaced apart from each other. 4. The base station according to claim 1,

[0095] (Appendix 5) The control unit, in the transmission process, transmits the second set of searching radio beams while changing a direction of the searching radio beams. 5. A base station as defined in claim 4.

[0096] (Appendix 6) The control unit, in the transmission process, Stopping transmission of the second set of search radio beams; transmitting a third set of search radio beams having the same frequency, spaced apart from each other, and not overlapping in direction with the second set of search radio beams; 5. A base station as defined in claim 4.

[0097] (Appendix 7) a storage unit for storing a table showing the correspondence between the frequencies of the plurality of search radio beams and the directions in which the beams are transmitted; The control unit transmits the plurality of search radio beams at a frequency and in a direction based on the table in the transmission process. 7. The base station according to claim 1,

[0098] (Appendix 8) the table indicates at least one of the number of the plurality of searching radio wave beams, the type of antenna, and the state of radio wave interference in correspondence with the frequency and the direction of transmission of the plurality of searching radio wave beams, The control unit is Executing an acquisition process to acquire at least any one of information on the number of the plurality of search radio beams, the type of antenna, and the state of radio wave interference; In the transmission process, the plurality of search radio beams are transmitted at a frequency and in a direction based on the table. 8. The base station according to claim 7.

[0099] (Appendix 9) The plurality of searching radio beams each have a different frequency and a different direction, In the receiving process, the radio wave received by the communication terminal has beam identification information that identifies the plurality of search radio beams, The control unit, in the communication process, Communicating with the communication terminal using a communication radio wave beam having a frequency and direction corresponding to the frequency and direction of the search radio wave beam specified by the beam specification information. 9. A base station according to any one of appendix 1 to 8.

[0100] (Appendix 10) A communication terminal that communicates with the base station according to claim 1, An antenna for transmitting and receiving radio waves; A control unit, The control unit is a receiving process for receiving, via the antenna, any one of a plurality of search radio beams transmitted from the base station and directed in different directions; an extraction process of extracting direction identification information for identifying a direction of the base station from the search radio beam received in the reception process; a transmission process of transmitting a radio beam toward the base station based on the direction identification information extracted in the extraction process; a communication process for communicating with a base station using the radio wave beam transmitted in the transmission process; A communication terminal that executes the above.

[0101] (Appendix 11) A communication method for a base station, comprising: A transmission process of transmitting a plurality of search radio beams from an antenna, the search radio beams being oriented in different directions; a receiving process for receiving radio waves transmitted from a communication terminal in response to the plurality of searching radio wave beams transmitted by the transmitting process; A communication process for communicating with a communication terminal that transmitted the radio wave received in the receiving process by using a radio wave beam for communication; A communication method comprising:

[0102] (Appendix 12) A communication method for a communication terminal, comprising: A receiving process for receiving, via an antenna, any one of a plurality of search radio beams transmitted from the base station according to claim 1 and directed in different directions; an extraction process of extracting direction identification information for identifying a direction of the base station from the search radio beam received in the reception process; a transmission process of transmitting a radio beam toward the base station based on the direction identification information extracted in the extraction process; a communication process for communicating with a base station using the radio wave beam transmitted in the transmission process; A communication method comprising:

[0103] (Appendix 13) A program for causing a computer to function as the control unit according to any one of appendixes 1 to 9.

[0104] (Appendix 14) A program for causing a computer to function as the control unit described in appendix 10.

[0105] [Additional Note 2] This disclosure includes the techniques described in the following appendices. However, the present invention is not limited to the techniques described in the following appendices, and various modifications are possible within the scope of the claims.

[0106] (Appendix 1) A base station for a communication terminal, an antenna for emitting a search radio beam for searching for a communication terminal and a communication radio beam for communicating with the communication terminal; at least one processor; The at least one processor: a transmission process of simultaneously transmitting a plurality of search radio beams from the antenna, the search radio beams being oriented in different directions; a receiving process for receiving radio waves transmitted from a communication terminal in response to the plurality of searching radio wave beams simultaneously transmitted by the transmitting process; A communication process for communicating with the communication terminal that transmitted the radio wave received in the receiving process by using a radio wave beam for communication; A base station that executes the above.

[0107] (Appendix 2) A base station as described in Appendix 1, wherein the multiple search radio beams include a first set of search radio beams having different frequencies.

[0108] (Appendix 3) The first set of searching radio beams includes a plurality of searching radio beams having different frequencies and adjacent to each other, 3. A base station as defined in claim 2.

[0109] (Appendix 4) The plurality of searching radio beams include a second set of searching radio beams having the same frequency and spaced apart from each other. 4. The base station according to claim 1,

[0110] (Appendix 5) The at least one processor, in the transmission process, transmits the second set of search radio beams while changing a direction of the search radio beams. 5. A base station as defined in claim 4.

[0111] (Appendix 6) The at least one processor, in the transmission process, Stopping transmission of the second set of search radio beams; transmitting a third set of search radio beams having the same frequency, spaced apart from each other, and not overlapping in direction with the second set of search radio beams; 5. A base station as defined in claim 4.

[0112] (Appendix 7) The plurality of searching radio beams each have a different frequency and a different direction, In the receiving process, the radio wave received by the communication terminal has beam identification information that identifies the plurality of search radio beams, The at least one processor, in the communication process, Communicating with the communication terminal using a communication radio wave beam having a frequency and direction corresponding to the frequency and direction of the search radio wave beam specified by the beam specification information. 7. A base station according to any one of claims 1 to 6.

[0113] (Appendix 8) a memory for storing a table showing the correspondence between the frequencies of the plurality of search radio beams and the directions in which the beams are transmitted; In the transmission process, the at least one processor transmits the plurality of search radio beams at a frequency and a direction based on the table. 8. The base station according to claim 1,

[0114] (Appendix 9) the table indicates at least one of the number of the plurality of searching radio wave beams, the type of antenna, and the state of radio wave interference in correspondence with the frequency and the direction of transmission of the plurality of searching radio wave beams, The at least one processor: Executing an acquisition process to acquire at least any one of information on the number of the plurality of search radio beams, the type of antenna, and the state of radio wave interference; In the transmission process, the plurality of search radio beams are transmitted at a frequency and in a direction based on the table. 9. A base station as defined in claim 8.

[0115] (Appendix 10) A communication terminal that communicates with the base station according to claim 1, An antenna for transmitting and receiving radio waves; at least one processor; The at least one processor: a receiving process for receiving, via the antenna, any one of a plurality of search radio beams transmitted from the base station and directed in different directions; an extraction process of extracting direction identification information for identifying a direction of the base station from the search radio beam received in the reception process; a transmission process of transmitting a radio beam toward the base station based on the direction identification information extracted in the extraction process; a communication process for communicating with a base station using the radio wave beam transmitted in the transmission process; A communication terminal that executes the above.

[0116] The base station and the communication terminal may further include a memory, and the memory may store a program for causing the at least one processor to execute each of the processes. [Explanation of symbols]

[0117] 1, 2 Communication Systems 10, 100 base stations 20, 200 communication terminals 11, 21, 101, 201 Antennas 12, 22, 102, 202 Transmitter / receiver 13, 23, 103, 203 Control section 104, 204 Storage section 105 Input / output section S1, S1a, S1b, S10, S10a, S10b Communication method S101a Acquisition process S102a Setting process S11a, S12b, S111a, S113b Transmission process S11b, S12a, S111b, S113a Reception Processing S112b Extraction process S13a, S13b, S121a, S121b Communication processing Ta, Tb table

Claims

1. A base station for a communication terminal, an antenna for emitting a search radio beam for searching for a communication terminal and a communication radio beam for communicating with the communication terminal; A control unit, The control unit is a transmission process of simultaneously transmitting a plurality of search radio beams from the antenna, the search radio beams being oriented in different directions; a receiving process for receiving radio waves transmitted from a communication terminal in response to the plurality of searching radio wave beams simultaneously transmitted by the transmitting process; A communication process for communicating with the communication terminal that transmitted the radio wave received in the receiving process by using a radio wave beam for communication; A base station that executes the above.

2. The plurality of searching radio beams include a first set of searching radio beams having mutually different frequencies, The base station according to claim 1 .

3. The first set of searching radio beams includes a plurality of searching radio beams having different frequencies and adjacent to each other. The base station according to claim 2.

4. The plurality of searching radio beams include a second set of searching radio beams having the same frequency and spaced apart from each other. A base station according to any one of claims 1 to 3.

5. The control unit, in the transmission process, transmits the second set of searching radio beams while changing a direction of the searching radio beams. The base station according to claim 4.

6. The control unit, in the transmission process, Stopping transmission of the second set of search radio beams; transmitting a third set of searching radio beams having the same frequency, spaced apart from each other, and not overlapping in direction with the second set of searching radio beams; The base station according to claim 4.

7. a storage unit for storing a table showing the correspondence between the frequencies of the plurality of search radio beams and the directions in which the beams are transmitted; The control unit transmits the plurality of search radio beams at a frequency and in a direction based on the table in the transmission process. The base station according to any one of claims 1 to 3.

8. the table indicates at least one of the number of the plurality of searching radio wave beams, the type of antenna, and the state of radio wave interference in correspondence with the frequency and the direction of transmission of the plurality of searching radio wave beams, The control unit is Executing an acquisition process to acquire at least any one of information on the number of the plurality of search radio beams, the type of antenna, and the state of radio wave interference; In the transmission process, the plurality of search radio beams are transmitted at a frequency and in a direction based on the table. The base station according to claim 7.

9. The plurality of searching radio beams each have a different frequency and a different direction, In the receiving process, the radio wave received by the communication terminal has beam identification information that identifies the plurality of search radio beams, The control unit, in the communication process, Communicating with the communication terminal using a communication radio wave beam having a frequency and direction corresponding to the frequency and direction of the search radio wave beam specified by the beam specification information. A base station according to any one of claims 1 to 3.

10. A communication terminal that communicates with the base station according to claim 1, An antenna for transmitting and receiving radio waves; A control unit, The control unit is a receiving process for receiving, via the antenna, any one of a plurality of search radio beams transmitted from the base station and directed in different directions; an extraction process of extracting direction identification information for identifying a direction of the base station from the search radio beam received in the reception process; a transmission process of transmitting a radio beam toward the base station based on the direction identification information extracted in the extraction process; a communication process for communicating with a base station using the radio wave beam transmitted in the transmission process; A communication terminal that executes the above.

11. A communication method for a base station, comprising: A transmission process of transmitting a plurality of search radio beams from an antenna, the search radio beams being oriented in different directions; a receiving process for receiving radio waves transmitted from a communication terminal in response to the plurality of searching radio wave beams transmitted by the transmitting process; A communication process for communicating with a communication terminal that transmitted the radio wave received in the receiving process by using a radio wave beam for communication; A communication method comprising:

12. A communication method for a communication terminal, comprising: A receiving process for receiving, via an antenna, any one of a plurality of search radio beams transmitted from the base station according to claim 1 and directed in different directions; an extraction process of extracting direction identification information for identifying a direction of the base station from the search radio beam received in the reception process; a transmission process of transmitting a radio beam toward the base station based on the direction identification information extracted in the extraction process; a communication process for communicating with a base station using the radio wave beam transmitted in the transmission process; A communication method comprising:

13. A program for causing a computer to function as the control unit according to claim 1.

14. A program for causing a computer to function as the control unit according to claim 10.

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