Wireless communication system

Abstract

To provide a wireless communication system that enables beamforming by using an optimized beam table, without a significant increase in costs of wireless communication devices.SOLUTION: A wireless communication system comprises a first wireless communication device and a server communicably connected with the first wireless communication device. The server selects an optimized beam table depending on the installation state of a second wireless communication device that is registered with a subscriber database and the first wireless communication device uses the beam table selected by the server to perform wireless communication with the second wireless communication device.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to wireless communication systems. [Background technology]

[0002] In order to increase the capacity of wireless communication, the frequency bands used are becoming wider and higher. In particular, the development of wireless communication devices using the millimeter wave band is progressing rapidly. For example, the 60 GHz band is being considered for use as a wireless access network for small cells and WISPs (Wireless Internet Service Providers) linked to mobile communication networks, or as a wireless backhaul link for wireless base stations, wireless relay stations, and public wireless LAN communication access points.

[0003] In the millimeter wave band, where propagation loss is large, beam antennas with high gain and sharp directionality are generally used. The IEEE802.llad standard takes into consideration the movement of communication partners and point-to-multipoint (P2MP) communication with multiple communication partners, and uses beamforming antennas whose beam direction can be changed by electrical control from a control unit. The IEEE802.llad standard also searches for the optimal beam direction between the local station and the other station when communication begins and successively during communication.

[0004] In recent years, the provision of Internet connection services using wireless access networks by WISPs is becoming more widespread. In these services, the location of the user's antenna is fixed and, in principle, does not move. In a WISP, the wireless communication equipment on the provider's side is the parent station, and the wireless communication equipment on the user's side is the child station. At least one of the parent station and child station has a beamforming antenna. In the process of performing beamforming, the master station and slave stations recognize each other's presence, select an appropriate beam, and communicate by switching to a Modulation and Coding Scheme (MCS) according to the radio wave quality. The installation status of the slave stations is registered and managed in a subscriber database. Such a subscriber database is used to ensure stable communication and improve communication quality, as described in Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 7,120,436 Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional beamforming technology, the wireless communication device may store a beam pattern table in advance. However, in conventional technology, in such a case, the radiation direction of each beam pattern is arranged so that the angular intervals are equal, so that a difference in gain occurs between the user in the direction of the beam peak and the user in the direction of the beam valley. For this reason, in conventional technology, a difference in gain may cause a difference in data rate because the MCS is switched. In addition, the beam pattern has a side lobe, which may cause interference and reduce communication quality. A method of solving this problem may be to use a beam pattern in which the direction of the interference source is a null point. Ideally, an optimized beam pattern would be used in which the beam is directed toward the user and there is a null point in the direction of the interference source. However, if this were to be implemented by improving wireless communication devices, it would likely be necessary to improve the hardware functions, resulting in a significant increase in costs.

[0007] The present invention has been made in consideration of the above circumstances, and provides a wireless communication system that can perform beamforming using an optimized beam table without causing a significant increase in the cost of wireless communication devices. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, a wireless communication system according to one embodiment of the present invention is a wireless communication system comprising a first wireless communication device and a server communicatively connected to the first wireless communication device, wherein the server stores a plurality of optimized beam tables and selects from among them an optimized beam table to be used by the first wireless communication device, and the first wireless communication device obtains the optimized beam table selected by the server by communicating with the server, and performs wireless communication using the obtained optimized beam table.

[0009] In one embodiment of the present invention, a server stores multiple optimized beam tables, the server selects an optimized beam table from among them, and a first wireless communication device acquires the selected optimized beam table by communicating with the server, and uses the optimized beam table to communicate with other wireless communication devices. As a result, according to one aspect of the present invention, the first wireless communication device can perform beamforming using an optimized beam table without causing a significant increase in cost.

[0010] In addition, in the wireless communication system according to an aspect of the present invention, the server may select an optimized beam table to be used by the first wireless communication device by referring to a subscriber database. As a result, according to one aspect of the present invention, the server can select an optimized beam table to be used by the first wireless communication device in advance without waiting for information necessary for selecting an optimized beam table to be notified from the first wireless communication device.

[0011] In addition, in a wireless communication system according to one embodiment of the present invention, the wireless communication system may further include a second wireless communication device that performs wireless communication with the first wireless communication device, and the installation location of the second wireless communication device and the installation direction of the antenna of the second communication device may be registered in the subscriber database. As a result, according to one aspect of the present invention, the server can obtain information regarding the installation location of the second wireless communication device and the installation direction of the antenna of the second wireless communication device by referring to the subscriber database, and can appropriately select the optimized beam table to be used by the first wireless communication device based on this information.

[0012] In the wireless communication system according to an aspect of the present invention, the subscriber database may be configured to register a latitude and longitude as an installation location of the second wireless communication device. As a result, according to one aspect of the present invention, the server can easily use information on the installation location of the second wireless communication device when selecting an optimized beam table to be used by the first wireless communication device.

[0013] In addition, in a wireless communication system according to one embodiment of the present invention, the subscriber database may further register the installation location of the first wireless communication device and the installation direction of the antenna of the first wireless communication device, and the latitude and longitude may be registered as the installation location of the first wireless communication device. As a result, according to one aspect of the present invention, when the server selects an optimized beam table to be used by the first wireless communication device, it can easily access both information relating to the first wireless communication device and information relating to the second wireless communication device by simply accessing a single database.

[0014] In addition, in a wireless communication system according to one embodiment of the present invention, the server may calculate a calculated direction of the second wireless communication device as seen from the first wireless communication device, and select an optimized beam table to be used by the first wireless communication device based on the calculated direction. As a result, according to one aspect of the present invention, by using a selected optimized beam table, the communication quality of the wireless communication between the first wireless communication device and the second wireless communication can be improved.

[0015] In addition, in a wireless communication system according to one aspect of the present invention, the optimized beam table may be configured so that the angular interval between beams in the vicinity of the optimized direction is narrower than the angular interval between beams in directions other than the vicinity of the optimized direction. As a result, according to one aspect of the present invention, it is possible to prevent the direction of the second wireless communication device as seen from the first wireless communication device from becoming a direction between beams in the beam table used, resulting in a deterioration in gain and a switch in MCS, thereby preventing a deterioration in the communication quality of the wireless communication between the first wireless communication device and the second wireless communication device.

[0016] According to the above aspect of the present invention, beamforming can be performed using an optimized beam table without causing a significant increase in the cost of the wireless communication device. [Brief description of the drawings]

[0017] [Figure 1] 1 is a diagram illustrating an example of the configuration of a wireless communication system assuming a WISP according to an embodiment. [Diagram 2] 2 is a diagram showing an example of use of a first wireless communication device and a second wireless communication device according to an embodiment. [Diagram 3] 1 is a block diagram showing an example of the configuration of a wireless communication device according to an embodiment. [Figure 4] FIG. 13 is a diagram showing the array factor of an optimized beam table according to an embodiment in polar coordinates. [Diagram 5] FIG. 2 is a diagram showing an example of the configuration of a station database in the subscriber database according to the embodiment; [Figure 6A] FIG. 4 is a diagram illustrating an example of a station database according to the embodiment. [Figure 6B]FIG. 4 is a diagram illustrating an example of a station database according to the embodiment. [Figure 7] 1 is a diagram showing a configuration of an antenna database that stores information on each antenna, of a subscriber database according to an embodiment. FIG. [Figure 8] FIG. 8 is a diagram showing an example of the antenna database of FIG. 7. [Figure 9] FIG. 2 is a diagram showing an example of the configuration of a wireless link database, which is part of a subscriber database and describes the relationship between two specific antennas. [Figure 10] FIG. 10 is a diagram illustrating an example of the wireless link database of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0019] (Example of wireless communication system configuration) FIG. 1 is a diagram showing an example of the configuration of a wireless communication system assuming a WISP (Wireless Internet Service Provider) according to an embodiment.

[0020] As shown in Fig. 1, a wireless communication system 1 includes a first wireless communication device 2 and a second wireless communication device 3. When there are multiple second wireless communication devices 3 and one is to be specified, it is expressed as a second wireless communication device 3-n (n is an integer equal to or greater than 1). In Fig. 1, there are a second wireless communication device 3-1, a second wireless communication device 3-2, a second wireless communication device 3-3, and a second wireless communication device 3-4 (n = 4). Also, when there are multiple second wireless communication devices 3 but one is not to be specified, each is referred to as a second wireless communication device 3, with no particular distinction being made. In addition, the first wireless communication device 2 is connected to a data center 4 via a network NW. The data center 4 includes a server 41. The server 41 includes a subscriber database 42 .

[0021] The first wireless communication device 2 is a base station or a parent station, and is connected to a higher-level network such as a provider network via a network NW such as an optical fiber line or other communication line, and is thereby connected to a network such as the Internet. The first wireless communication device 2 is a wireless communication device installed by a service provider such as a WISP or a wireless communication carrier. The first wireless communication device 2 obtains an optimized beam table from a server 41 via the network NW, and communicates with the second wireless communication device 3 using the obtained optimized beam table. The first wireless communication device 2 performs wireless communication with the second wireless communication device 3 by beamforming.

[0022] The second wireless communication device 3 is a terminal or a slave station of a fixed wireless access service, and is installed in a subscriber's home who uses a service provided by a service provider such as a WISP or a wireless communication carrier. The number of the second wireless communication device 3 may be one or more.

[0023] Each of the first wireless communication device 2 and the second wireless communication device 3 is equipped with a beamforming antenna and a control unit that executes beamforming within the device. The first wireless communication device 2 and the second wireless communication device 3 recognize each other's presence during the beamforming process, select an appropriate beam, and connect with an MCS (Modulation and Coding Scheme) according to the quality of the radio waves to perform wireless communication.

[0024] The subscriber database 42 stores information on subscribers, i.e., customers, and information on the second wireless communication device 3 installed for each subscriber. As part of the information on the second wireless communication device 3, the installation status of the second wireless communication device 3 is stored for each second wireless communication device 3. The subscriber database 42 may be provided in the server 41, or may be connected to the server 41, or may be provided in a server on a cloud that can communicate with the server 41.

[0025] The server 41 is installed in, for example, the data center 4. The server 41 has a subscriber database or is in a state where the server 41 can refer to the subscriber database, and has stored a large number of beam tables for beamforming antennas in advance. The server 41 selects an optimized beam table to be used by the first wireless communication device 2 from a large number of stored beam tables based on information from the subscriber database 42. For example, when the direction of the opposing second wireless communication device 3 as seen from the first wireless communication device 2 is set as the direction to be optimized, the server 41 calculates the direction to be optimized by referring to the subscriber database, and determines the optimized beam table based on the calculated direction. As a procedure for determining the optimized beam table, various methods are possible, such as selecting a beam table with a null point in the direction where an interference source exists, or selecting a beam table composed of beams with a wide beam half-width to avoid overreach interference and limiting the reach distance. The server 41 stores and holds a large number of optimized beam tables. Furthermore, when it is determined that a new optimized beam table should be prepared, a new optimized beam table is generated by selecting and combining appropriate ones from the stored AWV sets, or by designing and combining a new AWV, and the generated new optimized beam table is stored. As a method for the first wireless communication device 2 to use the optimized beam table, a method in which the first wireless communication device 2 adaptively calculates and prepares the optimized beam table is also conceivable, but adaptive calculation increases the load on the CPU (Central Processing Unit), so it is necessary to install a CPU with high processing power in the first wireless communication device 2, which results in a significant increase in cost. If the server 41 generates the optimized beam table, it is possible to avoid a significant increase in the cost of the first wireless communication device 2. Alternatively, a method is conceivable in which a large number of optimized beam tables assuming various situations are stored in advance in the storage 2231 held by the first wireless communication device 2, and these are appropriately selected and used, but in order to store a large number of optimized beam tables in advance, it is necessary to make the storage 2231 large-capacity, which results in a significant increase in cost.The server 41 accumulates the optimized beam table, which can prevent the cost of the first wireless communication device 2 from increasing significantly. The server 41 may be installed in a place other than the data center 4, may be a virtual server, or may be a cloud server. Information related to the first wireless communication device 2 installed by the WISP side may be registered separately in a base station database separate from the subscriber database 42, or may be registered in the subscriber database 42 together with information related to the second wireless communication device 3. When the information related to the first wireless communication device 2 is registered in the subscriber database 42, the server 41 can access both the information of the first wireless communication device 2 and the information of the second wireless communication device 3 by simply accessing the single subscriber database 42, which is efficient.

[0026] 1, a router (not shown) may be installed in the network NW, and the network NW may be connected to the Internet, etc. via the router. In this case, the first wireless communication device 2 or the second wireless communication device 3 is indirectly connected to the Internet, etc.

[0027] In addition, the first wireless communication device 2 and the second wireless communication device 3 are not limited to a service provider and its service user, but may be both installed as internal networks by an organization such as a company or public institution.

[0028] FIG. 2 is a diagram showing an example of use of the first wireless communication device 2 and the second wireless communication device 3 according to this embodiment. In FIG. 2, the first wireless communication device 2 is a master station, a PCP of IEEE802.11ad, and includes a beamforming antenna, and performs wireless communication using, for example, 60 GHz millimeter waves. The second wireless communication device 3 is a slave station, an STA of IEEE802.11ad, and includes a beamforming antenna, and performs wireless communication using, for example, 60 GHz millimeter waves.

[0029] The first wireless communication device 2 and the second wireless communication device 3 are not limited to a PCP and an STA. The first wireless communication device 2 may be a base station of a mobile communication network, or an AP (Access Point) of various other wireless communication systems. The second wireless communication device 3 may be Customer Premises Equipment (CPE) of a mobile communication network, a user terminal (User Equipment (UE)), or a user terminal of various other wireless communication systems.

[0030] (Explanation of terms used in the embodiment) Here, an overview of a wireless communication device that performs communication using a beamforming antenna and terms used in the embodiments will be described. The basic configuration of a beamforming antenna is that each aligned antenna element is powered with a phase shift, which causes radio waves with the same phase to be emitted in the desired direction, resulting in a beam with sharp directionality.

[0031] When designing a beam pattern for a beam that radiates radio waves in a desired direction, the arrangement of each antenna element in the antenna array, the distance between the antenna elements, the wavelength of the radiated radio waves, etc. are taken into consideration to calculate phase conditions so that the radio waves radiated from each antenna element interfere and reinforce each other in the desired direction, and the phase and power to be supplied to each antenna element are determined.

[0032] A wireless communication device equipped with a beamforming antenna has a beam table composed of multiple Antenna Weight Vectors (AWVs). Here, AWV refers to a vector that represents the gain of an amplitude adjuster and the phase shift amount of a variable phase shifter corresponding to each antenna element. When a beamforming antenna is composed of n antenna elements, a set of n AWVs represents one beam pattern.

[0033] The radiation pattern of the entire array antenna calculated based only on the AWV is called the array factor. If the antenna elements are omnidirectional, the array factor is the radiation pattern of the entire array antenna. If the antenna elements have directionality, the product of the array factor and the radiation pattern of the antenna elements is the radiation pattern of the entire array antenna.

[0034] (Example of the configuration of a wireless communication device) 3 is a block diagram showing an example of the configuration of a wireless communication device according to an embodiment. As shown in FIG. The control unit 22 includes a BBIC 221, an RFIC 222, a control system 223, an NI (Network Interface) 224, and a PS (Power Supply) 225. The RFIC 222 includes a LUT 2221 and a beamformer 2222 . The control system 223 includes storage 2231 .

[0035] The first wireless communication device 2 sequentially switches between the quasi-omni beam pattern and the beam table according to, for example, the IEEE802.11ad protocol to communicate with the second wireless communication device 3. Furthermore, when the number of second wireless communication devices 3 and the direction of each second wireless communication device 3 from the first wireless communication device 2 are known, the first wireless communication device 2 communicates using an optimized beam table instead of the standard beam table.

[0036] The antenna 21 is a digital phased array type beamforming antenna in which a plurality of antenna elements are arranged and can be electrically controlled by a set value of an AWV (Antenna Weight Vector).

[0037] The BBIC 221 is, for example, a Baseband Integrated Circuit. The BBIC 221 is a circuit section that processes a Baseband signal, and also mediates control of the RFIC 222 from the control system 223 in some cases.

[0038] The RFIC222 is, for example, a Radio Frequency Integrated Circuit, which processes high-frequency signals, transmits and receives millimeter-wave signals, and performs beamforming. The RFIC222 sets the AWV by setting a value in the LUT2221.

[0039] The LUT 2221 is a look-up table that stores a plurality of AWV sets as a beam pattern table. Each AWV set corresponds to one beam pattern and is composed of AWVs corresponding to the number of antenna elements.

[0040] The beamformer 2222 controls the power supply to the antenna elements based on the AWV setting value.

[0041] The control system 223 is connected to the network NW connected to the first wireless communication device 2 via the NI 224. The control system 223 mediates communication between the network NW via the NI 224 and the wireless communication network connected by a communication line via the antenna 21 by controlling the BBIC 221 and the RFIC 222. The control system 223 controls the BBIC 221 and the RFIC 222 by referring to various databases according to, for example, a program. The control system 223 acquires an optimized beam table according to the arrangement status of the first wireless communication device 2 and the second wireless communication device 3 from the server 41, and accumulates the acquired optimized beam table in the storage 2231. The control system 223 may include a CPU (Central Processing Unit), a SoC (System-on-a-Chip), an ASIC (Application Specific Integrated Circuit), or the like.

[0042] The storage 2231 stores in advance a set of AWVs for a quasi-omni beam pattern and a standard beam table in which the beam angles are spaced at equal intervals. The storage 2231 also stores an optimized beam table acquired by the control system 223 from the server 41. The storage 2231 is a recording medium such as a hard disk drive (HDD), a solid state drive (SSD), or a flash memory. Alternatively, the storage 2231 may be a non-volatile storage area included inside an ASIC, an SoC, or the like. The area for storing the optimized beam table acquired from the server 41 may be a volatile storage area.

[0043] The NI 224 is a network interface, and is an interface for connecting the first wireless communication device 2 to the network NW. The PS 225 is a power supply unit, and supplies power supplied from an external source to each component of the first wireless communication device 2.

[0044] (Optimized beam table) Next, an example of the optimized beam table will be described. Fig. 4 is a diagram showing the array factor of the optimized beam table according to this embodiment in polar coordinates. The optimized beam table in Fig. 4 is formed by optimizing for six directions when the installation direction of the second wireless communication device 3, which is a slave station, as seen from the beam forming antenna of the first wireless communication device 2, which is a master station, is 36 degrees, 60 degrees, 90 degrees, 106 degrees, 128 degrees, and 140 degrees. Therefore, in the optimized beam table, the angular interval between beams in the vicinity of the optimized direction is narrower than the angular interval between beams in directions other than the vicinity of the optimized direction.

[0045] Figure 4 also shows an example of a digital phased array antenna consisting of a planar patch antenna with 16 transmitting elements and 16 receiving elements, where the array factor has been designed to cover an angular range of 120 degrees from 30 degrees to 150 degrees, with east defined as 0 degrees, north defined as 90 degrees, and west defined as 180 degrees when the front of the antenna is facing north. Although the example in FIG. 4 is an example of an angle range of 120 degrees from 30 degrees to 150 degrees, the angle range is not limited to this and may be any angle range according to the intended use.

[0046] Here, when a standard beam table in which the angular intervals of the beams are equal is used, the direction of the second wireless communication device 3, which is a child station, falls in the valley between the beams, resulting in a deterioration in gain. For example, the required receiving sensitivity for MCS10 is -55 dBm, the required receiving sensitivity for MCS11 is -54 dBm, and the required receiving sensitivity for MCS12 is -53 dBm. When the standard beam table is used in this way, the MCS is switched with only a slight difference in radio wave quality (here, receiving sensitivity). As a result, when the standard beam table is used, the radio wave quality of users located exactly in the direction of the beam is good, while the radio wave quality of users located between the beams is degraded.

[0047] Even if the distance from the antenna of the first wireless communication device 2 providing the service to the antenna of the user's second wireless communication device 3 is the same, it may happen that one user can use MCS12 while another user can only use MCS11. In the IEEE802.llad standard, the data rates for each MCS are 3,080 Mbps for MCS10, 3,850 Mbps for MCS11, and 4,620 Mbps for MCS12.

[0048] In contrast, in this embodiment, by narrowing the beam spacing in the vicinity of the direction to be optimized, compared to when a standard beam table in which the angular spacing of beams is equal is used, it is possible to prevent the gain from deteriorating due to the second wireless communication device 3, which is a child station, being located in a valley between beams, and thus prevent a slow MCS from being selected.

[0049] Fig. 5 is a diagram showing an example of the configuration of the station database of the subscriber database 42 according to this embodiment. As shown in Fig. 5, the station database is composed of STATION_ID, SUBSCRIBER_ID, ACCOUNT_ID, NAME_FIRST, NAME_MIDDLE, NAME_LAST, ADDRESS, EQUIPMENT_TYPE, BF_ANT_NO, BF_ANT_ID_01, BF_ANT_ID_02, BF_ANT_ID_03, BF_ANT_ID_04, BF_ANT_ID_05, BF_ANT_ID_06, BF_ANT_ID_07, and BF_ANT_ID_08.

[0050] STATION_ID is a unique ID that identifies the first wireless communication device 2 and the second wireless communication device 3, the TYPE is an integer (INT), and the data length is 4 bytes (BYTES). SUBSCRIBER_ID is a unique ID that identifies a user associated with the second wireless communication device 3, its TYPE is an integer (INT), and its data length is 4 bytes. ACCOUNT_ID is a unique ID that identifies an account related to the payment of expenses incurred in the second wireless communication device 3, its TYPE is an integer (INT), and its data length is 4 bytes.

[0051] NAME_FIRST, NAME_MIDDLE, and NAME_LAST are the user's name, the TYPE is a variable-length character string (VARCHAR), and the data length is variable. ADDRESS is the user's address, TYPE is a variable-length character string (VARCHAR), and the data length is variable.

[0052] EQUIPMENT_TYPE is an integer value corresponding to an enum type (enumeration type) value indicating the model of the second wireless communication device 3, where TYPE is an integer (INT) and the data length is 4 bytes. BF_ANT_NO is the number of beamforming antennas connected to the second wireless communication device 3, TYPE is an integer (INT), and the data length is 4 bytes. BF_ANT_ID_Ol to BF_ANT_ID_08 store unique IDs that identify antenna information, with BF_ANT_NO as the upper limit, and serve as indexes for referencing the antenna database. Each of BF_ANT_ID_Ol to BF_ANT_ID_08 has an integer (INT) TYPE and a 4-byte data length.

[0053] Fig. 6A is a diagram showing an example of a station database according to this embodiment, showing columns 1 to 8. Fig. 6B is a diagram showing an example of a station database according to this embodiment, showing columns 9 to 17. Although Fig. 6A and Fig. 6B are one table, they are shown in two for convenience. In FIG. 6A and FIG. 6B, the first wireless communication device 2 with ACCOUNT_ID of 00000000, STATION_ID of 00060128 with all BS in the name field, is installed by the WISP as a master station (PCP). The six second wireless communication devices 3 with STATION_IDs of 00062048 to 00062053 are CPE-type wireless communication devices (STAs) installed in the homes of users who have contracted with a WISP. The first wireless communication device 2 with STATION_ID 00060128 has two beamforming antennas connected thereto, and the six devices with STATION_IDs 00062048 to 00062053 each have one beamforming antenna connected thereto.

[0054] Fig. 7 is a diagram showing the configuration of an antenna database that stores information on each antenna in the subscriber database 42 according to this embodiment. As shown in Fig. 7, the antenna database is made up of BF_ANT_ID, BF_ANT_TYPE, BF_ANT_LATITUDE, BF_ANT_LONGITUDE, BF_ANT_ORIENTATION, BF_ANT_MAX_SECTOR_NO, BF_ANT_MAX_BEAM_NO, BF_ANT_CUR_BEAMTABLE, and BF_ANT_CUR_BEAM_NO.

[0055] BF_ANT_ID is a unique ID that identifies antenna information, its TYPE is an integer (INT), and its data length is 4 bytes. BF_ANT_TYPE is an integer value corresponding to an enum value indicating the type of antenna, where TYPE is an integer (INT) and the data length is 4 bytes.

[0056] BF_ANT_LATITUDE is the latitude of the antenna installation location. Here, north latitude is input, TYPE is a double-precision floating-point number (DOUBLE), and the data length is 8 bytes. BF_ANT_LONGITUDE is the longitude of the antenna installation location. Here, east longitude is input, the TYPE is a double-precision floating-point number (DOUBLE), and the data length is 8 bytes.

[0057] BF_ANT_ORIENTATION indicates the installation orientation of the antenna, with north being 0 degrees or 360 degrees, east being 90 degrees, south being 180 degrees, and west being 270 degrees, and the direction input is the front of the beamforming antenna, i.e., 90 degrees in the array factor design. In other words, for a beamforming antenna with 0 degrees input into BF_ANT_ORIENTATION, 0 degrees is east, 90 degrees is north, and 180 degrees is west in the array factor design of Figure 4. For a beamforming antenna with 90 degrees input into BF_ANT_ORIENTATION, 0 degrees is south, 90 degrees is east, and 180 degrees is north in the array factor design. Also, for BF_ANT_ORIENTATION, the TYPE is a double-precision floating-point number (DOUBLE), and the data length is 8 bytes.

[0058] BF_ANT_MAX_SECTOR_NO is the maximum number of sectors in a Sector Level Sweep (SLS), the TYPE is an integer (INT), and the data length is 4 bytes. BF_ANT_MAX_BEAM_NO is the maximum number of beams in beamforming operation using the standard beam table or the optimized beam table, and the TYPE is an integer (INT) and the data length is 4 bytes.

[0059] BF_ANT_CUR_BEAMTABLE contains the UUID of an optimized beam table if one exists, has a TYPE of a universally unique identifier (UUID) and a data length of 16 bytes. The optimized beam table is stored in the server 41 in association with the UUID, and the optimized beam table can be identified by this UUID.

[0060] BF_ANT_CUR_BEAM_NO is the number of beams used in the optimized beam table and takes a value equal to or smaller than BF_ANT_MAX_BEAM_NO, its TYPE is an integer (INT), and its data length is 4 bytes.

[0061] FIG. 8 is a diagram showing an example of the antenna database of FIG. The two antennas with BF_ANT_IDs of 00002624 and 00002625 are antennas connected to a first wireless communication device 2 with STATION_ID of 00060128. The two antennas have the same latitude and longitude values, and the antenna with 00002624 is installed at an azimuth angle of 345 degrees, i.e., tilted 15 degrees west from north, while the antenna with 00002625 is installed at an azimuth angle of 75 degrees, i.e., tilted 15 degrees north from east.

[0062] The antenna with BF_ANT_ID of 00065536 is connected to the second wireless communication device 3 with STATION_ID of 00062048. The antenna with BF_ANT_ID of 00065537 is connected to the second wireless communication device 3 with STATION_ID of 00062049. The antenna with BF_ANT_ID of 00065538 is connected to the second wireless communication device 3 with STATION_ID of 00062050. The antenna with BF_ANT_ID of 00065539 is connected to the second wireless communication device 3 with STATION_ID of 00062051. The antenna with BF_ANT_ID of 00065540 is connected to the second wireless communication device 3 with STATION_ID of 00062052. The antenna with BF_ANT_ID of 00065541 is connected to the second wireless communication device 3 with STATION_ID of 0062053. The antennas of these slave stations are attached to poles so that their orientation can be adjusted, and when installed, they are each set up so that their front faces the wireless communication device 00060128, which is the master station.

[0063] Fig. 9 is a diagram showing an example of the configuration of a wireless link database that describes the relationship between two specific antennas in the subscriber database 42. As shown in Fig. 9, the wireless link database is composed of FROM_BF_ANT_ID, TO_BF_ANT_ID, LINK_ORIENTATION, LINK_BF_DIRECTION, and LINK_DISTANCE.

[0064] FROM_BF_ANT_ID is the ID of the antenna on the source side of the wireless link, the TYPE is an integer (INT), and the data length is 4 bytes. TO_BF_ANT_ID is the ID of the destination antenna, the TYPE is an integer (INT), and the data length is 4 bytes.

[0065] LINK_ORIENTATION is the direction calculated from the BF_ANT_LATITUDE and BF_ANT_LONGITUDE of the antenna specified by FROM_BF_ANT_ID as the starting point and the BF_ANT_LATITUDE and BF_ANT_LONGITUDE of the antenna specified by TO_BF_ANT_ID as the end point. LINK_ORIENTATION has a TYPE of double-precision floating-point number (DOUBLE) and a data length of 8 bytes.

[0066] LINK_BF_DIRECTION is the direction in the antenna array factor design converted from the BF_ANT_ORIENTATION (belonging to the antenna database) and LINK_ORIENTATION (belonging to the wireless link database) of the antenna specified by FROM_BF_ANT_ID. LINK_BF_DIRECTION has a TYPE of double-precision floating-point number (DOUBLE) and a data length of 8 bytes.

[0067] LINK_DISTANCE is the calculated distance between the antennas, is recorded in meters (m), has a TYPE of double-precision floating-point number (DOUBLE), and has a data length of 8 bytes.

[0068] FIG. 10 is a diagram showing an example of the wireless link database of FIG. As shown in Figure 10, information on one wireless link between an antenna with BF_ANT_ID 00002624 and an antenna with BF_ANT_ID 00065536 is recorded in the database for two cases: one where the starting point is the antenna with BF_ANT_ID 00002624, and the other where the starting point is the antenna with BF_ANT_ID 00065536. Note that the calculations used the Geodetic Reference System 1980 (GRS80) ellipsoid model, which is one of the models of the Earth ellipsoid in geodesy.

[0069] 10, the server 41 determines that the second wireless communication device 3, which is the communication target, is installed in six directions from the antenna, namely, 39 degrees, 15 degrees, 345 degrees, 329 degrees, 307 degrees, and 295 degrees. In addition, the server 41 determines the directions of 36 degrees, 60 degrees, 90 degrees, 106 degrees, 128 degrees, and 140 degrees as optimization target directions in the array factor design, taking into account the direction in which the beamforming antenna of the first wireless communication device 2 is installed.

[0070] If the server 41 already has a beam table optimized for this optimization target direction that matches MM60_16_16_A, which is the BF_ANT_TYPE of the antenna with FROM_BF_ANT_ID of 00002624, the server 41 determines that beam table as the optimized beam table that the first wireless communication device 2 with STATION_ID of 00060128 should acquire for the antenna with FROM_BF_ANT_ID of 00002624. If an appropriate optimized beam table does not exist in the server 41, the server 41 creates a new beam table, generates a UUID, links the beam table to the UUID and stores it, and determines this as the optimized beam table that should be acquired by the first wireless communication device 2 with STATION_ID 00060128.

[0071] The beam table with UUID c4a0469c-0bd8-4f51-8b76-7a9163cd89e9 determined by the server 41 in this manner is the beam table in Fig. 4. The first wireless communication device 2 with STATION_ID of 00060128 acquires this beam table from the server 41 and applies it to the antenna with BF_ANT_ID of 00002624. The first wireless communication device 2 with STATION_ID of 00060128 uses the acquired optimized beam table to provide a service as shown in Fig. 2, for example.

[0072] For wireless links originating from a slave station, the antenna of the slave station is set to face approximately the master station, so the LINK_BF_DIRECTION is approximately 90 degrees. For example, the beam table with UUID 779f6ed0-aa12-4561-8e9c-b1a121ce4f56 is optimized for an 88 degree direction, the beam table with UUID 43148b25-11bb-4257-b298-8818e5624e84 is optimized for a 90 degree direction, and the beam table with UUID d172b0ba-2b35-44db-8ea5-715e60b1da98 is optimized for a 91 degree direction.

[0073] As described above, in this embodiment, a large number of optimized beam tables are stored in the server 41, and an optimized beam table to be used by the first wireless communication device is selected from among them. In addition, information on the latitude, longitude, and installation direction of the antenna is stored in the subscriber database 42 held by the server 41. In this embodiment, the server 41 calculates the direction of another wireless communication device that is a communication partner as seen from a certain wireless communication device based on the stored information. In this embodiment, the first wireless communication device 2, which is the master station, acquires and uses the optimized beam table selected based on the calculated direction of the second wireless communication device 3, which is the slave station. In this embodiment, the optimized beam table is configured so that the interval between beams is narrow in the vicinity of the optimization target direction.

[0074] As a result, according to this embodiment, the first wireless communication device 2, which is the master station, acquires and uses the optimized beam table from the server 41, so that the first wireless communication device 2 can use the optimized beam table without causing a significant increase in the cost of the first wireless communication device 2. Also, by communicating with the second wireless communication device 3 using an optimized beam table in which the angle interval between beams is narrowed in the vicinity of the optimization target direction, it is possible to suppress deterioration of gain depending on the direction and improve communication quality.

[0075] The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment, and various modifications and substitutions can be made within the scope that does not deviate from the gist of the present invention. [Explanation of symbols]

[0076] 1...wireless communication system 2...first wireless communication device 3-1 to 3-6, 3...second wireless communication device 4...data center 41...server 42...subscriber database 21...antenna 22...control unit 221...BBIC 222...RFIC 223...control system 224...NI 225...PS 2221...LUT 2222...beamformer 2231...storage

Claims

1. A wireless communication system including a first wireless communication device, a server communicably connected to the first wireless communication device, and a second wireless communication device that wirelessly communicates with the first wireless communication device, The server stores a plurality of optimized beam tables, and selects an optimized beam table to be used by the first wireless communication device from among the optimized beam tables by referring to a subscriber database; The first wireless communication device acquires the optimized beam table selected by the server by communicating with the server, and performs wireless communication using the acquired optimized beam table; The subscriber database registers an installation location of the second wireless communication device and an installation direction of an antenna of the second wireless communication device, In the optimized beam table, an angular interval between beams in the vicinity of an optimized direction is narrower than an angular interval between beams in a direction other than the vicinity of the optimized direction. Wireless communication system.

2. The subscriber database has registered therein the latitude and longitude of the location of the second wireless communication device.

2. The wireless communication system according to claim 1.

3. The subscriber database further registers an installation location of the first wireless communication device and an installation direction of an antenna of the first wireless communication device, and registers latitude and longitude as the installation location of the first wireless communication device.

3. The wireless communication system according to claim 2.

4. The server, calculating a calculated direction of the second wireless communication device as seen from the first wireless communication device, and selecting an optimized beam table to be used by the first wireless communication device based on the calculated direction; 4. The wireless communication system according to claim 3.

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