Wireless communication system

Abstract

We provide a wireless communication system that can offer appropriate services tailored to the communication partner while keeping implementation costs down. [Solution] The wireless communication system 1 comprises a wireless communication device 10 that supports multiple services, a wireless device 20 that communicates wirelessly with the wireless communication device 10 and receives services provided by the wireless communication device 10, and at least one reflector 50 that enables wireless communication between the wireless communication device 10 and the wireless device 20 via a detour route Q2 different from a straight path Q1 connecting the wireless communication device 10 and the wireless device 20.

Description

Technical Field

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[0001] The present invention relates to a wireless communication system.

Background Art

[0002] Conventionally, a technique for assisting the operation of a train formation by presenting an image of a home to the driver of the train formation is known. In this technique, an image captured by a camera installed at the home is transmitted to the train formation, and a wireless communication system that receives the transmitted image and outputs it to a liquid crystal display device installed in the driver's cab of the train formation for display is used. For details of such a wireless communication system, refer to, for example, Patent Documents 1 and 2 below.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, due to train schedule disruptions or maintenance, the relationship between the track and the train formation entering the track often has to be changed. Therefore, in the above-described wireless communication system, it is preferable that the identification settings for communication (for example, the center frequency and SSID (Service Set Identifier) during wireless communication) are common settings for all train formations. Therefore, in the conventional wireless communication system, in order to provide an appropriate image to the train formation entering the home track, a detection system for detecting the train formation entering the home track is separately required, resulting in a problem of high introduction costs.

[0005] This invention has been made in view of the above circumstances, and aims to provide a wireless communication system that can provide appropriate services according to the communication partner while keeping implementation costs down. [Means for solving the problem]

[0006] To solve the above problems, a wireless communication system (1, 2) according to a first aspect of the present invention comprises a wireless communication device (10) that supports multiple services, a wireless device (20) that communicates wirelessly with the wireless communication device and receives services provided by the wireless communication device, and at least one reflective member (50) that enables wireless communication between the wireless communication device and the wireless device via a detour route (Q2) different from a straight path (Q1) connecting the wireless communication device and the wireless device.

[0007] A wireless communication system according to a first aspect of the present invention comprises a wireless communication device that supports multiple services, a wireless device that communicates wirelessly with the wireless communication device and receives services provided by the wireless communication device, and a reflector. The reflector enables wireless communication between the wireless communication device and the wireless device via a detour route different from the straight path connecting the wireless communication device and the wireless device. As a result, even if there are obstacles on the straight path, wireless communication via the detour route is possible between the wireless communication device and the wireless device, and as a result, it is possible to provide appropriate services according to the communication partner while keeping the introduction cost down.

[0008] Furthermore, a wireless communication system according to a second aspect of the present invention is a wireless communication system according to a first aspect of the present invention, wherein the reflective member is positioned off the straight path, reflects the beam (BM) of the wireless communication device toward the wireless device, and reflects the beam of the wireless device toward the wireless communication device.

[0009] Furthermore, a wireless communication system according to a third aspect of the present invention is a wireless communication system according to a second aspect of the present invention, wherein the wireless communication device and the wireless equipment are equipped with a phased array antenna (11), and the direction of the beam is the direction in which the main lobe of the radiation pattern of the phased array antenna appears.

[0010] Furthermore, a wireless communication system according to a fourth aspect of the present invention is a wireless communication system according to a third aspect of the present invention, wherein the wireless communication device includes a beamtable (BT) to which first information indicating the direction of the beam of the phased array antenna and second information relating to the services to be provided are associated, and the beam of the phased array antenna is controlled using the beamtable, and control is performed to provide services corresponding to the controlled beam direction based on the second information associated with the first information indicating the controlled beam direction.

[0011] Furthermore, a wireless communication system according to a fifth aspect of the present invention is a wireless communication system according to any one of the first to fourth aspects of the present invention, wherein the wireless communication device is installed on a platform (HM), and the wireless equipment is installed on a train set (TR) entering the platform.

[0012] Furthermore, a wireless communication system according to a sixth aspect of the present invention is a wireless communication system according to a fifth aspect of the present invention, wherein the wireless communication device provides a service to transmit an image of the platform corresponding to the platform number to which the train set is entering the platform, and the wireless device receives the image transmitted from the wireless communication device and outputs it to a display device (40) installed on the train set for display. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide appropriate services tailored to the communication partner while keeping implementation costs down. [Brief explanation of the drawing]

[0014] [Figure 1] This is a block diagram showing a wireless communication system according to a first embodiment of the present invention. [Figure 2] This figure shows an example of a beam table used in the first embodiment of the present invention. [Figure 3] This figure shows an example of a beam formed in a wireless communication system according to the first embodiment of the present invention. [Figure 4] This is a block diagram showing a wireless communication system according to a second embodiment of the present invention. [Figure 5] This is a timing chart for illustrating the operation of a wireless communication system according to a second embodiment of the present invention. [Figure 6] This figure shows a modified example of a wireless communication system according to an embodiment of the present invention. [Modes for carrying out the invention]

[0015] Hereinafter, with reference to the drawings, a wireless communication system according to an embodiment of the present invention will be described in detail.

[0016] [First Embodiment] Figure 1 is a block diagram showing a wireless communication system according to a first embodiment of the present invention. As shown in Figure 1, the wireless communication system 1 of this embodiment comprises a wireless communication device 10, a plurality of wireless devices 20, and a reflector 50 (reflective member), and is a system capable of point-to-multipoint communication between the wireless communication device 10 and the plurality of wireless devices 20. Such a wireless communication system 1 can provide services according to the wireless devices 20 by having the wireless communication device 10 and the plurality of wireless devices 20 communicate wirelessly.

[0017] The wireless communication system 1 performs wireless communication using high-frequency signals such as microwaves, millimeter waves, and sub-millimeter waves. Also, the wireless communication system 1 performs wireless communication compliant with, for example, the wireless communication standard IEEE802.11ad. The wireless communication device 10 corresponds to a base station device that manages connections, and corresponds to, for example, an AP (Access Point) or a PCP (PBSS Control Point) defined by the wireless communication standard IEEE802.11. The plurality of wireless devices 20 correspond to wireless terminals connected to the base station device, and correspond to, for example, STAs (STAtions) defined by the wireless communication standard IEEE802.11. In FIG. 1, two wireless devices 20a and 20b are shown as the plurality of wireless devices 20, but the number of wireless devices 20 is not limited to two. The number of wireless devices 20 may be three or more.

[0018] The wireless communication device 10 includes a phased array antenna 11 and a control unit 12, and provides a service according to the direction of the beam BM of the phased array antenna 11. The service provided by the wireless communication device 10 includes, for example, providing voice, images, characters, graphics, and other various data suitable for the wireless device 20. Note that the service provided by the wireless communication device 10 is not limited to providing the above various data and may be any service.

[0019] The phased array antenna 11 includes a plurality of antenna elements (not shown) and is an antenna capable of freely changing the beam pattern (antenna directivity). That is, the phased array antenna 11 is an antenna having a beamforming function. In the phased array antenna 11, the beamforming function is realized by adjusting at least one of the intensity and phase of the signal (transmission signal) supplied to the plurality of antenna elements or the signal (reception signal) supplied from the plurality of antenna elements.

[0020] In the phased array antenna 11, by adjusting the above-mentioned intensity and phase, it is possible to form an arbitrary beam pattern. In the present embodiment, for the sake of easy understanding, it is assumed that two beams BM shown in FIG. 1 are formed as the beam pattern of the phased array antenna 11. Note that the direction of the formed beam BM is the direction in which the main lobe of the radiation pattern of the phased array antenna 11 appears. Of the two beams BM, one beam BM1 is directed toward the reflector 50, and the other beam BM2 is directed toward the wireless device 20b. Note that the beam BM1 is directed toward the wireless device 20a by being reflected by the reflector 50.

[0021] Note that in the present embodiment, as shown in FIG. 1, the angle of the beam BM radiated from the wireless communication device 10 in the right direction of the drawing is set to 0°. Then, the angle clockwise (clockwise) from this angle (0°) is positive, and the angle counterclockwise (counterclockwise) is negative. For this reason, the beam BM1 directed toward the reflector 50 is represented by a negative angle, and the beam BM2 directed toward the wireless device 20b is represented by a positive angle.

[0022] The control unit 12 controls the direction of the beam BM of the phased array antenna 11 and performs control to provide a service corresponding to the direction of the beam BM of the phased array antenna 11. Here, the control unit 12 controls the direction of the beam BM of the phased array antenna 11 so that the received power of the wireless device 20 performing wireless communication is maximized. In the example shown in FIG. 1, the direction of the beam BM is controlled so that the received power of the wireless device 20a is maximized, and the direction of the beam BM2 is controlled so that the received power of the wireless device 20b is maximized.

[0023] After controlling the direction of the beam BM of the phased array antenna 11, the control unit 12 performs control to provide a service corresponding to the direction of the beam BM of the phased array antenna 11. Specifically, the control unit 12 performs control using a beam table BT in which information indicating the direction of the beam BM of the phased array antenna 11 (first information) and information regarding the service to be provided (second information) are associated with each other.

[0024] Figure 2 shows an example of a beam table used in the first embodiment of the present invention. As shown in Figure 2, the beam table BT is a table to which beam sectors (first information), beam direction (first information), and data (second information) are associated.

[0025] The beam sector is information that identifies the beam formed by the phased array antenna 11, and for example, an integer (number) in the range of 0 to 63 is stored. The beam direction is information that indicates the direction of the beam BM of the phased array antenna 11, and for example, any angle in the range of -60° to +60° is stored. Since there is a one-to-one correspondence between the beam sector and the beam direction, the beam direction is determined when the beam sector is identified.

[0026] The data is information indicating the data used depending on the service provided. For example, Data A indicates that the data is used for Service A, Data B indicates that the data is used for Service B, etc. If no service is provided, "None" is stored.

[0027] In the example shown in Figure 2, when the beam sector is 10, the beam direction is stored as -35°; when the beam sector is 25, the beam direction is stored as -10°; when the beam sector is 40, the beam direction is stored as 10°; and when the beam sector is 55, the beam direction is stored as 35°. Note that in the example shown in Figure 2, the correspondence between the beam sector and the beam direction is omitted when the beam sector is not 10, 25, 40, or 55.

[0028] Furthermore, in the example shown in Figure 2, when the beam sector is 10-25 (beam direction is -35° to -10°), data A is stored as data. When the beam sector is 40-55 (beam direction is 10° to 35°), data B is stored as data. Note that in the example shown in Figure 2, when the beam sector is 0-9, 26-39, and 56-63, "None" is stored as data.

[0029] The control unit 12 controls the direction of the beam BM of the phased array antenna 11 using the beam table BT shown in Figure 2. After controlling the direction of the beam BM of the phased array antenna 11, the control unit 12 performs control to provide services corresponding to the controlled beam BM direction, based on data associated with the beam sector that identifies the direction of the beam BM.

[0030] For example, suppose that wireless device 20a is positioned at an angle of -10° relative to the wireless communication device 10, and wireless device 20b is positioned at an angle of 10° relative to the wireless communication device 10. When the control unit 12 controls the direction of the beam BM of the phased array antenna 11 to the direction specified by beam sector 25, it performs control to provide data A to wireless device 20a located in that direction. Also, when the control unit 12 controls the direction of the beam BM of the phased array antenna 11 to the direction specified by beam sector 40, it performs control to provide data B to wireless device 20b located in that direction.

[0031] The wireless device 20 communicates wirelessly with the wireless communication device 10 and receives services provided by the wireless communication device 10. The wireless device 20 is equipped with a phased array antenna similar to the phased array antenna 11 of the wireless communication device 10. The wireless device 20 also controls the direction of the beam BM of the phased array antenna using a beam table BT similar to the beam table BT shown in Figure 2.

[0032] The wireless device 20 may be fixed in place or movable. When the wireless device 20 is fixed in place, the direction of the beam BM formed by the phased array antenna 11 of the wireless communication device 10 and the direction of the beam formed by the phased array antenna of the wireless device 20 remain unchanged. In contrast, when the wireless device 20 is movable, the direction of the beam BM formed by the phased array antenna 11 of the wireless communication device 10 and the direction of the beam formed by the phased array antenna of the wireless device 20 change according to the position of the wireless device 20.

[0033] Here, it is preferable that the wireless device 20 is located at a distance of at least twice the half-width of the beam BM formed by the phased array antenna 11 provided on the wireless communication device 10, in the angular direction relative to the wireless communication device 10. For example, it is preferable that the angle between the line passing through the wireless communication device 10 and wireless device 20a and the line passing through the wireless communication device 10 and wireless device 20b is at least twice the half-width of the beam BM. This is to suppress unintended data communication.

[0034] Figure 3 shows an example of a beam formed in a wireless communication system according to the first embodiment of the present invention. As described above, the direction of the beam BM formed by the phased array antenna 11 is the direction in which the main lobe of the radiation pattern of the phased array antenna 11 appears. The full width at half maximum of the beam BM is the angle of the beam BM at the point where the intensity of the beam BM decreases by 3 dB from the maximum value of the main lobe.

[0035] The reflector 50 enables wireless communication between the wireless communication device 10 and the wireless device 20a via a detour route Q2 that is different from the straight path Q1 connecting the wireless communication device 10 and the wireless device 20a. The reflector 50 is provided, for example, to enable wireless communication via the detour route Q2 even when wireless communication between the wireless communication device 10 and the wireless device 20a is not possible via the straight path Q1 due to an obstacle X present on the straight path Q1.

[0036] The reflector 50 is positioned off the straight path Q1 and reflects the beam BM1 of the wireless communication device 10 toward the wireless device 20a, and conversely, reflects the beam of the wireless device 20a toward the wireless communication device 10. Any reflector 50 can be used as long as it enables wireless communication between the wireless communication device 10 and the wireless device 20a via the detour path Q2. For example, the reflector 50 may have a planar reflective surface, or it may have a curved reflective surface (for example, a concave or convex surface). Furthermore, the reflector 50 may be configured so that the reflective surface does not move, or it may be configured so that the reflective surface moves (for example, to swing).

[0037] The reflector 50 can be installed at any location as long as it enables wireless communication between the wireless communication device 10 and the wireless device 20a via the detour route Q2. It is preferable that the wireless communication device 10 and the wireless device 20 know the location or direction in which the reflector 50 is installed, but this is not required. In Figure 1, only one reflector 50 is shown, but multiple reflectors (two or more) may be provided. Also, in Figure 1, the reflector 50 is shown installed on the side of the wireless device 20a, but the reflector 50 may also be installed on the side of the wireless device 20b, or the reflector 50 may be installed only on the side of the wireless device 20b.

[0038] In the above configuration, when the wireless communication device 10 is powered on, the control unit 12 first controls the phased array antenna 11 by referring to the beam table BT shown in Figure 2, and sequentially changes the direction of beam BM. Then, the control unit 12 controls the direction of beam BM of the phased array antenna 11 so that the received power of the wireless device 20 performing wireless communication is maximized. In the example shown in Figure 1, the direction of beam BM1 is controlled so that the received power of wireless device 20a is maximized, and the direction of beam BM2 is controlled so that the received power of wireless device 20b is maximized.

[0039] Here, if there is an obstacle X in the straight path Q1 connecting the wireless communication device 10 and the wireless device 20a, the received power of the wireless device 20a will be extremely low, or it will be impossible to perform wireless communication between the wireless communication device 10 and the wireless device 20a at all. In such a case, the control unit 12 of the wireless communication device 10 will, for example, control the beam BM1 to point towards the reflector 50, so that wireless communication can be performed between the wireless communication device 10 and the wireless device 20a via the detour path Q2.

[0040] Next, the control unit 12 refers to the beam table BT shown in Figure 2 and performs control to provide services according to the direction of the controlled beam BM. For example, the control unit 12 refers to the beam table BT and provides data A corresponding to the direction (-35°) where beam sector 10 is specified to a wireless device 20a located in the direction of beam BM1 reflected by the reflector 50 located in that direction. The control unit 12 also refers to the beam table BT and provides data B corresponding to the direction (10°) where beam sector 40 is specified to a wireless device 20b located in that direction. In this way, services according to the direction of beam BM of the phased array antenna 11 are provided.

[0041] As described above, this embodiment includes a wireless communication device 10 that supports multiple services, wireless devices 20 (20a, 20b) that communicate wirelessly with the wireless communication device 10 and receive services provided by the wireless communication device 10, and a reflector 50. The reflector 50 enables wireless communication between the wireless communication device 10 and the wireless devices 20a via a detour route Q2 that is different from the straight path Q1 connecting the wireless communication device 10 and the wireless devices 20a. As a result, even if an obstacle X is present on the straight path Q1, wireless communication between the wireless communication device 10 and the wireless devices 20a is possible via the detour route Q2, and as a result, it is possible to provide appropriate services according to the communication partner while keeping the introduction cost down.

[0042] [Second Embodiment] Figure 4 is a block diagram showing a wireless communication system according to a second embodiment of the present invention. The basic configuration of the wireless communication system 2 of this embodiment is the same as that of the wireless communication system 1 of the first embodiment. Therefore, in Figure 4, components that are the same as those shown in Figure 1 are denoted by the same reference numerals. The wireless communication system 2 of this embodiment is applied to a monitoring system that monitors platform headmarks at stations, etc.

[0043] As shown in Figure 4, the wireless communication system 2 of this embodiment includes a wireless communication device 10, a plurality of wireless devices 20, and a reflector 50, as well as a plurality of image transmission systems 30 and a plurality of monitors 40 (display devices). The wireless communication device 10 and the plurality of image transmission systems 30 are installed on the station platform HM, and the plurality of wireless devices 20 and monitors 40 are installed on each of the plurality of train TR (train sets). In this embodiment, two reflectors 50 are provided.

[0044] The image transmission system 30 includes a camera group 31 and an image synthesis device 32. Images captured by the camera group 31 are synthesized by the image synthesis device 32 and transmitted to the wireless communication device 10. In the example shown in Figure 4, there is an image transmission system 30a that captures an image of one platform of the home station (hereinafter referred to as "platform 1") and an image transmission system 30b that captures an image of the other platform of the home station (hereinafter referred to as "platform 2"). Although Figure 4 shows two image transmission systems 30a and 30b as multiple image transmission systems 30, the number of image transmission systems 30 is not limited to two. There may be three or more image transmission systems 30.

[0045] The image transmission system 30a comprises a camera group 31a and an image combining device 32a. The camera group 31a comprises multiple cameras connected by cable CB1. The multiple cameras of the camera group 31a are arranged along the platform HM (along the direction of train TR entry) on the track 1 side of the platform HM. In other words, the multiple cameras of the camera group 31a are arranged to capture images from different positions on the track 1 side of the platform HM. The image combining device 32a combines (encodes) the images captured by the multiple cameras of the camera group 31a and transmitted by cable CB1. The image combining device 32a is connected to port P1 of the wireless communication device 10 and outputs the combined image to the wireless communication device 10.

[0046] The image transmission system 30b comprises a camera group 31b and an image combining device 32b. The camera group 31b comprises multiple cameras connected by cable CB2. The multiple cameras in the camera group 31b are arranged along the platform HM (along the direction of train TR entry) on the track 2 side of the platform HM. In other words, the multiple cameras in the camera group 31b are arranged to capture images from different positions on the track 2 side of the platform HM. The image combining device 32b combines (encodes) the images captured by the multiple cameras in the camera group 31b and transmitted by cable CB2. The image combining device 32b is connected to port P2 of the wireless communication device 10 and outputs the combined image to the wireless communication device 10.

[0047] The wireless communication device 10 controls the beam BM1 formed by the phased array antenna 11 so that it is directed towards the wireless device 20a installed on the train TR1 entering track 1 (or the train TR1 departing from track 1). If wireless communication is not possible due to an obstacle X (e.g., a passenger) on the straight path Q1 connecting the wireless communication device 10 and the wireless device 20a, the wireless communication device 10 controls the beam BM1 formed by the phased array antenna 11 so that it is directed towards the reflector 50. This enables wireless communication between the wireless communication device 10 and the wireless device 20a via the detour path Q2. The wireless communication device 10 then provides a service to transmit the image input to port P1 towards the wireless device 20a located in the direction of the beam BM1 reflected by the reflector 50.

[0048] Thus, in this embodiment, the port P1 of the wireless communication device 10 is associated with the beam BM1 transmitted toward the wireless device 20a or the reflector 50. In other words, in this embodiment, the beam table BT shown in Figure 2 stores information indicating that data A is data input from port P1. For example, identification information that identifies port P1 is stored as data A in the beam table BT shown in Figure 2.

[0049] Furthermore, the wireless communication device 10 controls the beam BM2 formed by the phased array antenna 11 so that it is directed toward the wireless device 20b installed on the train TR2 entering track 2 (or the train TR2 departing from track 2). It is also possible that wireless communication may be impossible due to unillustrated obstacles on the straight path connecting the wireless communication device 10 and the wireless device 20b; therefore, it is preferable to install a reflector similar to the reflector 50 on the track 2 side as well. It is also preferable that the wireless communication device 10 controls the beam BM2 formed by the phased array antenna 11 so that it is directed toward an unillustrated reflector installed on the track 2 side. The wireless communication device 10 then provides a service of transmitting the image input to port P2 toward the wireless device 20b located in the direction of the beam BM2.

[0050] Thus, in this embodiment, port P2 of the wireless communication device 10 is associated with beam BM2 transmitted toward the wireless device 20b or a reflector (not shown). In other words, in this embodiment, the beam table BT shown in Figure 2 stores information indicating that data B is data input from port P2. For example, identification information that identifies port P2 is stored as data B in the beam table BT shown in Figure 2.

[0051] Monitor 40 is equipped with a display device such as a liquid crystal display device, and decodes and displays images received by the wireless device 20 and output from the wireless device 20. Monitor 40 is installed, for example, in the driver's cab of a train TR. In the example shown in Figure 4, monitor 40a is installed on train TR1 which enters track 1 of platform HM, and monitor 40b is installed on train TR2 which enters track 2 of platform HM. Note that although two monitors 40a and 40b are shown as multiple monitors 40, the number of monitors 40 is not limited to two. Monitor 40 may be installed, for example, on all trains TR that are scheduled to enter platform HM.

[0052] Figure 5 is a timing chart illustrating the operation of a wireless communication system according to a second embodiment of the present invention. For the sake of simplicity, the explanation here will use the example of train TR1 entering platform HM track 1 and train TR2 entering platform HM track 2 simultaneously.

[0053] The wireless communication device 10 broadcasts beacons at regular time intervals (step S11). When train TR1 enters platform HM track 1 and train TR2 enters platform HM track 2, the beacons transmitted from the wireless communication device 10 are received by wireless devices 20a installed on train TR1 and wireless devices 20b installed on train TR2. Upon receiving the beacons, wireless devices 20a and 20b confirm the SSID and other information and then send an association request to the wireless communication device 10 (step S12).

[0054] When the wireless communication device 10 receives association requests transmitted from wireless devices 20a and 20b, it sends an ACK (ACKnowledgement) to each of the wireless devices 20a and 20b (step S13). This establishes an association between the wireless communication device 10 and the wireless devices 20a and 20b.

[0055] Once the association is established, the wireless communication device 10 and the wireless devices 20a and 20b search for the transmit beam sector (step S14). For example, the wireless communication device 10 and the wireless devices 20a and 20b enter a quasi-omnidirectional state when receiving and search for the transmit beam sector.

[0056] Here, if an obstacle X (e.g., a passenger) exists in the straight path Q1 connecting the wireless communication device 10 and the wireless device 20a, the wireless communication device 10 and the wireless device 20a may not be able to find the transmission beam sector. In such cases, the wireless communication device 10 and the wireless device 20a control the transmission beam so that it points towards the reflector 50, for example. Similarly, if an obstacle (e.g., a passenger) exists in the straight path connecting the wireless communication device 10 and the wireless device 20b, the wireless communication device 10 and the wireless device 20b may not be able to find the transmission beam sector. In such cases, the wireless communication device 10 and the wireless device 20b control the transmission beam so that it points towards a reflector (not shown), for example.

[0057] Once the search for the transmit beam sector is complete, the optimal transmit and receive beam sector is searched between the wireless communication device 10 and wireless devices 20a and 20b (step S15). Specifically, the receiving side is set to beamforming mode, and the process of searching for the optimal beam sector (beam direction) for both transmit and receive is performed.

[0058] The optimal beam sector is the beam sector in which the received power is maximized on the wireless devices 20a and 20b. If there are no obstacles X (e.g., passengers) in the straight path Q1 connecting the wireless communication device 10 and wireless device 20a, and no obstacles (e.g., passengers) in the straight path (not shown) connecting the wireless communication device 10 and wireless device 20b, then the transmitting and receiving beam directions (directions in which the main lobes appear) of the wireless communication device 10 and wireless devices 20a and 20b are directly facing each other. When the optimal transmitting and receiving beam sector is found, for example, as shown in Figure 4, the beam BM1 reflected by the reflector 50 is directed towards the wireless device 20a installed on train TR1, and the beam BM2 is directed towards the wireless device 20b installed on train TR2.

[0059] Here, if an obstacle X (e.g., a passenger) exists in the straight path Q1 connecting the wireless communication device 10 and the wireless device 20a, the wireless communication device 10 and the wireless device 20a may not be able to find the optimal transmit / receive beam sector. In such cases, the wireless communication device 10 and the wireless device 20a control the transmit / receive beams to point towards the reflector 50, for example. Similarly, if an obstacle (e.g., a passenger) exists in the straight path connecting the wireless communication device 10 and the wireless device 20b, the wireless communication device 10 and the wireless device 20b may not be able to find the optimal transmit / receive beam sector. In such cases, the wireless communication device 10 and the wireless device 20b control the transmit / receive beams to point towards a reflector (e.g., not shown).

[0060] Furthermore, the position of wireless device 20a changes according to the movement of train TR1, and the position of wireless device 20b changes according to the movement of train TR2. Therefore, the search for the optimal transmit / receive beam sector will continue at least until trains TR1 and TR2 stop.

[0061] Once the optimal transmit / receive beam sectors are found, the wireless communication device 10 refers to the beam table BT and transmits the data corresponding to the found optimal beam sectors as data frames to the wireless devices 20a and 20b, respectively (step S16). Specifically, the wireless communication device 10 transmits the image input to port P1, identified by the identification information corresponding to the beam sector of beam BM1 (the image output from the image transmission system 30a), toward the wireless device 20a located in the direction of beam BM1 reflected by the reflector 50. The wireless communication device 10 also transmits the image input to port P2, identified by the identification information corresponding to the beam sector of beam BM2 (the image output from the image transmission system 30b), toward the wireless device 20b located in the direction of beam BM2.

[0062] When wireless devices 20a and 20b receive a data frame transmitted from the wireless communication device 10, they send an ACK (step S17). Then, wireless devices 20a and 20b output the received image data to monitors 40a and 40b, respectively (step S18). As a result, images captured by the camera group 31a of the image transmission system 30a are displayed on monitor 40a installed on train TR1, and images captured by the camera group 31b of the image transmission system 30b are displayed on monitor 40b installed on train TR2.

[0063] As described above, in this embodiment, the wireless communication device 10 is installed on platform HM, wireless devices 20a and 20b that communicate with the wireless communication device 10 are installed on train TR1 and TR2 respectively, and the reflector 50 is placed in a predetermined position. For example, the reflector 50 enables wireless communication between the wireless communication device 10 and the wireless devices 20a via a detour route Q2 that is different from the straight path Q1 connecting the wireless communication device 10 and the wireless devices 20a. As a result, even if an obstacle X is present on the straight path Q1, wireless communication between the wireless communication device 10 and the wireless devices 20a is possible via the detour route Q2.

[0064] The wireless communication device 10 controls the direction of beam BM1 according to the position of wireless device 20a and transmits the image captured by the image transmission system 30a (an image of platform HM on track 1 where train TR1 will enter) to wireless device 20a for display on monitor 40a. The wireless communication device 10 also controls the direction of beam BM2 according to the position of wireless device 20b and transmits the image captured by the image transmission system 30b (an image of platform HM on track 2 where train TR2 will enter) to wireless device 20b for display on monitor 40b.

[0065] Thus, in this embodiment, without providing a separate detection system to detect trains entering the platform of the platform HM, an image of the platform of the platform HM to which the train TR is entering can be displayed on the monitor 40 installed on the train TR entering the platform of the platform HM. In other words, in this embodiment as well, it is possible to provide appropriate services according to the communication partner while keeping the introduction cost down.

[0066] In this embodiment, it is desirable that the angle between the line passing through the wireless communication device 10 and wireless equipment 20a and the line passing through the wireless communication device 10 and wireless equipment 20b at the location where the association request shown in Figure 5 is transmitted be at least twice the half-width of beam BM. This is to suppress unintended data communication. Furthermore, it is preferable that the movable range of beams BM1 and BM2 formed by the phased array antenna 11 of the wireless communication device 10 be set to the minimum possible depending on the movable range of the wireless equipment 20 installed on the train TR and the position of the reflector 50. This is to prevent false detection of the optimal transmission beam sector caused by multipath due to unintended reflections.

[0067] Furthermore, it is desirable that the reflector 50 be located within the movable range of beams BM1 and BM2 formed by the phased array antenna 11 of the wireless communication device 10, and that it does not obstruct the line of sight to the train TR and the wireless equipment 20 from the perspective of the wireless communication device 10. For example, it is desirable that the reflector 50 be located outside the train TR (away from the platform HM). This is to prevent the detour route by the reflector 50 (for example, detour route Q2) from becoming an unintended communication route to the train TR.

[0068] Furthermore, means for detecting the location from which the aforementioned association request is transmitted include speed information from the train TR during stopping (decelerating), distance information to the stopping position, and GPS (Global Positioning System) signals. The wireless communication device 10 and wireless equipment 20 initiate the association request as a trigger after detecting the above location using these signals.

[0069] Although a wireless communication system according to an embodiment of the present invention has been described above, the present invention is not limited to the above embodiments and can be freely modified within the scope of the present invention. For example, the reflector 50 in the first and second embodiments above was for providing a detour route Q2 different from the straight path Q1 connecting the wireless communication device 10 and the wireless equipment 20a, but a reflector may also be provided to prevent wireless communication by side lobes from unintended directions.

[0070] Figure 6 shows a modified example of a wireless communication system according to an embodiment of the present invention. In the modified example shown in Figure 6, in addition to the reflector 50 for providing a bypass path Q2, a reflector 51 is provided to prevent wireless communication by side lobes from unintended directions. This reflector 51 is, for example, used in wireless communication between the wireless communication device 10 and the wireless device 20b to prevent wireless communication by side lobes from the wireless communication device 10 toward the wireless device 20a. Note that the arrangement, shape, size, number, etc. of the reflector 51 shown in Figure 6 are merely examples and are arbitrary.

[0071] Furthermore, the service provided in the second embodiment described above displays an image of the platform number of the platform number of the platform number of the train entering the platform number of the platform number of the train on a monitor 40 installed in the train entering the platform number of [Explanation of Symbols]

[0072] 1,2…Wireless communication system, 10…Wireless communication device, 11…Phased array antenna, 20…Wireless equipment, 40…Display device, 50…Reflective material, BM…Beam, BT…Beam table, HM…Home, Q1…Straight route, Q2…Detour route, TR…Train

Claims

1. Wireless communication device compatible with multiple services, A wireless communication device and a wireless device that performs wireless communication and receives services provided by the wireless communication device, A reflective member that enables wireless communication between the wireless communication device and the wireless device via a detour route different from a straight path connecting the wireless communication device and the wireless device, A wireless communication system equipped with [the following features].

2. The wireless communication system according to claim 1, wherein the reflective member is positioned off the straight path and reflects the beam of the wireless communication device toward the wireless device and the beam of the wireless device toward the wireless communication device.

3. The aforementioned wireless communication device and wireless equipment are equipped with a phased array antenna. The beam direction is the direction in which the main lobe of the radiation pattern of the phased array antenna appears. The wireless communication system according to claim 2.

4. The wireless communication device includes a beam table in which first information indicating the beam direction of the phased array antenna and second information relating to the services to be provided are associated. The beam table is used to control the beam direction of the phased array antenna, and based on the second information associated with the first information indicating the controlled beam direction, the device performs control to provide services corresponding to the controlled beam direction. The wireless communication system according to claim 3.

5. The aforementioned wireless communication device has a home installed, The aforementioned wireless equipment is installed in the train set entering the platform. A wireless communication system according to any one of claims 1 to 4.

6. The wireless communication device provides a service that transmits an image of the platform corresponding to the platform number on which the train set is entering the platform. The wireless device receives the image transmitted from the wireless communication device and outputs it to a display device installed in the train set for display. The wireless communication system according to claim 5.

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