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, and a wireless device 20 that communicates wirelessly with the wireless communication device 10 and receives services provided by the wireless communication device 10. The wireless communication device 10 performs control to provide a service corresponding to the wireless device 20 when the deviation between the direction of its own beam and the direction of the beam of the wireless device 20 is less than or equal to a specified value.

Description

Technical Field

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

Background Art

[0002] Conventionally, a technique for assisting the operation of a vehicle formation by presenting an image of a home to the driver of the vehicle formation is known. In this technique, a wireless communication system is used that transmits an image captured by a camera installed at the home to the vehicle formation, receives the transmitted image, and outputs and displays it on a liquid crystal display device installed in the driver's seat of the vehicle formation. For details of such a wireless communication system, see, 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 platform and the incoming vehicle formation is often forced to change. For this reason, 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 vehicle formations. Therefore, in the conventional wireless communication system, in order to provide an appropriate image to the vehicle formation entering the platform of the home, a detection system for detecting the vehicle formation entering the platform of the home 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 according to a first aspect of the present invention is a wireless communication system (1, 2) comprising a wireless communication device (10) that corresponds to a plurality of services and a wireless device (20) that communicates wirelessly with the wireless communication device and receives services provided by the wireless communication device, wherein the wireless communication device performs a first control to provide a service corresponding to the wireless device when the deviation between the beam direction of the device and the beam direction of the wireless device is less than or equal to a specified value.

[0007] A wireless communication system according to a first aspect of the present invention provides a service tailored to a wireless device when the deviation between the beam direction of the wireless device and the beam direction of the wireless device is below a specified value. This makes it possible to provide appropriate services tailored to the communication partner while keeping implementation costs down.

[0008] Furthermore, in a wireless communication device according to a second aspect of the present invention, in a wireless communication system according to a first aspect of the present invention, if the discrepancy between the beam direction of the wireless device and the beam direction of the wireless device is greater than the specified value, the wireless communication device performs a second control to adjust the beam direction with the wireless device without providing a service corresponding to the wireless device.

[0009] Furthermore, in a wireless communication device according to a third aspect of the present invention, in a wireless communication system according to a first or second aspect of the present invention, the wireless communication device determines whether the deviation between the direction of its own beam and the direction of the wireless device's beam is greater than the specified value, based on the difference between first beam identification information that identifies the beam of its own device and second beam identification information that identifies the beam of the wireless device transmitted from the wireless device.

[0010] Furthermore, in a wireless communication device according to a fourth aspect of the present invention, in a wireless communication system according to a first or second aspect of the present invention, the wireless communication device determines whether the discrepancy between the beam direction of its own device and the beam direction of the wireless device is greater than the specified value, based on the difference between first beam direction information indicating the beam direction of its own device and second beam direction information indicating the beam direction of the wireless device transmitted from the wireless device.

[0011] Furthermore, in a wireless communication device according to a fifth aspect of the present invention, in a wireless communication system according to a second aspect of the present invention, the wireless communication device performs the second control when at least one of the discrepancy between the direction of the transmitting beam of the device and the direction of the receiving beam of the wireless device, and the discrepancy between the direction of the receiving beam of the device and the direction of the transmitting beam of the wireless device, is greater than the specified value.

[0012] Furthermore, in a wireless communication system according to the fifth aspect of the present invention, the wireless communication device determines whether the deviation between the direction of the transmitting beam of the device and the direction of the receiving beam of the wireless device is greater than the specified value based on the difference between first transmitting beam identification information that identifies the transmitting beam of the device itself and second receiving beam identification information that identifies the receiving beam of the wireless device transmitted from the wireless device. The wireless communication device determines whether the deviation between the direction of the receiving beam of the device itself and the direction of the transmitting beam of the wireless device is greater than the specified value based on the difference between first receiving beam identification information that identifies the receiving beam of the device itself and second transmitting beam identification information that identifies the transmitting beam of the wireless device transmitted from the wireless device.

[0013] Furthermore, in a wireless communication system according to the fifth aspect of the present invention, the wireless communication device determines whether the discrepancy between the direction of the transmitting beam of the device and the direction of the receiving beam of the wireless device is greater than the specified value, based on the difference between first transmitting beam direction information indicating the direction of the transmitting beam of the device itself and second receiving beam direction information indicating the direction of the receiving beam of the wireless device transmitted from the wireless device. The wireless communication device determines whether the discrepancy between the direction of the receiving beam of the device itself and the direction of the transmitting beam of the wireless device is greater than the specified value, based on the difference between first receiving beam direction information indicating the direction of the receiving beam of the device itself and second transmitting beam direction information indicating the direction of the transmitting beam of the wireless device transmitted from the wireless device.

[0014] Furthermore, in the eighth aspect of the present invention, the wireless communication device is a wireless communication system according to any one of the first to seventh aspects 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.

[0015] Furthermore, in the ninth aspect of the present invention, the wireless communication device is installed on a platform (HM) in a wireless communication system according to any one of the first to eighth aspects of the present invention, and the wireless equipment is installed on a train set (TR) entering the platform.

[0016] Furthermore, in a wireless communication device according to a tenth aspect of the present invention, in a wireless communication system according to a ninth aspect of the present invention, the wireless communication device provides a service of transmitting 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]

[0017] According to the present invention, there is an effect that an appropriate service according to a communication partner can be provided while suppressing introduction costs.

Brief Description of Drawings

[0018] [Figure 1] It is a block diagram showing a wireless communication system according to a first embodiment of the present invention. [Figure 2] It is a diagram showing an example of a beam formed in the first embodiment of the present invention. [Figure 3] It is a diagram showing an example of a beam table used in the first embodiment of the present invention. [Figure 4] It is a diagram for explaining the basic operation of a wireless communication system according to a first embodiment of the present invention. [Figure 5] It is a block diagram showing a wireless communication system according to a second embodiment of the present invention. [Figure 6] In the second embodiment of the present invention, it is an explanatory diagram in the case where there is an influence of reflection. [Figure 7] It is a timing chart for explaining a first operation of a wireless communication system according to a second embodiment of the present invention. [Figure 8] It is a timing chart for explaining a second operation of a wireless communication system according to a second embodiment of the present invention. [Figure 9] It is a timing chart for explaining a third operation of a wireless communication system according to a second embodiment of the present invention.

Modes for Carrying Out the Invention

[0019] Hereinafter, a wireless communication system according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0020] 〔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 and at least one wireless device 20, and is a system capable of point-to-point communication or point-to-multipoint communication between the wireless communication device 10 and the wireless device 20. Such a wireless communication system 1 can provide services corresponding to the wireless device 20 by having the wireless communication device 10 and the wireless device 20 communicate wirelessly.

[0021] The wireless communication system 1 performs wireless communication using high-frequency signals such as microwaves, quasi-millimeter waves, and millimeter waves. The wireless communication system 1 also performs wireless communication compliant with the wireless communication standard IEEE 802.11ad. The wireless communication device 10 corresponds to a base station device that manages connections, and corresponds to, for example, an AP (Access Point) or PCP (PBSS Control Point) as defined in the wireless communication standard IEEE 802.11. At least one wireless device 20 corresponds to a wireless terminal connected to the base station device, and corresponds to, for example, an STA (Station) as defined in the wireless communication standard IEEE 802.11. Although only one wireless device 20 is shown in Figure 1, the number of wireless devices 20 may be multiple (two or more).

[0022] The wireless communication device 10 comprises a phased array antenna 11 and a control unit 12, and provides a service among several services that is appropriate for the wireless device 20. Examples of services provided by the wireless communication device 10 include the provision of voice, images, text, graphics, and other various data suitable for the wireless device 20. However, the services provided by the wireless communication device 10 are not limited to the provision of the above-mentioned various data, and may be any service.

[0023] The phased array antenna 11 is an antenna equipped with multiple antenna elements (not shown) that can freely change its beam pattern (antenna directivity). In other words, the phased array antenna 11 is an antenna with beamforming capabilities. In the phased array antenna 11, the beamforming function is achieved by adjusting at least one of the intensity and phase of the signal supplied to the multiple antenna elements (transmitted signal) or the signal supplied from the multiple antenna elements (received signal).

[0024] In the phased array antenna 11, any beam pattern can be formed by adjusting the intensity and phase as described above. For example, the beam BM shown in Figure 2 is formed as the beam pattern of the phased array antenna 11. 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.

[0025] Figure 2 shows an example of a beam formed in 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.

[0026] The control unit 12 controls the direction of the beam of the phased array antenna 11 and performs the control to provide the services described above. 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. The control unit 12 controls the direction of the beam BM of the phased array antenna 11 using a beam table BT. After controlling the direction of the beam BM of the phased array antenna 11, the control unit 12 performs the control to provide the services described above.

[0027] Figure 3 shows an example of a beam table used in the first embodiment of the present invention. As shown in Figure 3, the beam table BT is a table in which beam sectors and beam directions are associated. The beam sector is information that identifies the beam formed by the phased array antenna 11, and stores, for example, an integer (number) in the range of 0 to 63. The beam direction is information that indicates the direction of the beam BM of the phased array antenna 11, and stores, for example, any angle in the range of -90° to +90°. Since the beam sector and beam direction are associated one-to-one, when the beam sector is identified, the beam direction is identified.

[0028] In the example shown in Figure 3, 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 3, the correspondence between the beam sector and the beam direction is omitted when the beam sector is not 10, 25, 40, or 55.

[0029] 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 3.

[0030] 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 does not change in principle. 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 changes according to the position of the wireless device 20.

[0031] Figure 4 is a diagram illustrating the basic operation of a wireless communication system according to the first embodiment of the present invention. Figure 4(a) is an explanatory diagram showing the case when reflection does not affect the system, and Figure 4(b) is an explanatory diagram showing the case when reflection does affect the system. As shown in Figure 4, for the wireless communication device 10, the angle of the beam BM radiated to the right in the drawing is set to 0°, and for the wireless device 20, the angle of the beam BM radiated to the left in the drawing is set to 0°. For both the wireless communication device 10 and the wireless device 20, angles moving clockwise from the angle (0°) are considered positive, and angles moving counterclockwise are considered negative.

[0032] For example, if there are no obstacles between the wireless communication device 10 and the wireless device 20, and there is no influence of reflection, then, as shown in Figure 4(a), the beam of the wireless communication device 10 will be directed towards the wireless device 20, and the beam of the wireless device 20 will be directed towards the wireless communication device 10. In other words, the angle of the beam of the wireless communication device 10 and the angle of the beam of the wireless device 20 will be the same (or approximately the same). In the example shown in Figure 4(a), the beam angles of both the wireless communication device 10 and the wireless device 20 will be approximately +20°.

[0033] In contrast, if an obstacle exists between the wireless communication device 10 and the wireless device 20, and the signal is affected by reflection from structure X, the beams of the wireless communication device 10 and the wireless device 20 will point in the direction of structure X, as shown in Figure 4(b). In other words, the beam angles of the wireless communication device 10 and the beam angles of the wireless device 20 will be significantly different. In the example shown in Figure 4(b), the beam angle of the wireless communication device 10 will be approximately -55°, and the beam angle of the wireless device 20 will be approximately +55°.

[0034] In this embodiment, as shown in Figure 4(b), if the difference between the beam direction of the wireless communication device 10 and the beam direction of the wireless device 20 is large (larger than a predetermined value), the control unit 12 of the wireless communication device 10 performs control (second control) to adjust the beam direction with respect to the wireless device 20 without providing a service appropriate to the wireless device 20. This control is performed because the control unit 12 of the wireless communication device 10 might mistakenly recognize that the wireless device 20 is located in the direction of structure X, and therefore may not be able to provide a service suitable for the wireless device 20.

[0035] In contrast, as shown in Figure 4(a), when the deviation between the beam direction of the wireless communication device 10 and the beam direction of the wireless device 20 is approximately zero (when the deviation is less than or equal to the specified value), the control unit 12 of the wireless communication device 10 performs control (first control) to provide a service corresponding to the wireless device 20. This is because the wireless device 20 is located in the direction recognized by the control unit 12 of the wireless communication device 10, and therefore a service suitable for the wireless device 20 can be provided. The specified value can be set to any value considering the installation status of the wireless communication system 1, radio wave conditions, etc.

[0036] Here, information regarding the beam of the wireless device 20 is transmitted and received between the wireless communication device 10 and the wireless device 20. The control unit 12 of the wireless communication device 10 uses the beam information transmitted from the wireless device 20 and the beam information of the wireless communication device 10 to determine whether the deviation between the beam direction of the wireless communication device 10 and the beam direction of the wireless device 20 is greater than the specified value. As the beam information, the beam sector (information identifying the beam) or beam direction (information indicating the beam direction) stored in the beam table BT shown in Figure 3 can be used.

[0037] For example, the control unit 12 of the wireless communication device 10 may make the above determination based on the difference between a beam sector that identifies the beam of the wireless communication device 10 (first beam identification information) and a beam sector that identifies the beam of the wireless device 20 transmitted from the wireless device 20 (second beam identification information). Alternatively, the control unit 12 of the wireless communication device 10 may make the above determination based on the difference between information indicating the direction of the beam of the wireless communication device 10 (first beam direction information) and information indicating the direction of the beam of the wireless device 20 transmitted from the wireless device 20 (second beam direction information).

[0038] Here, the beams of the wireless communication device 10 and the wireless device 20 include a transmitting beam and a receiving beam. Therefore, if at least one of the discrepancies between the direction of the transmitting beam of the wireless communication device 10 and the direction of the receiving beam of the wireless device 20, and the discrepancies between the direction of the receiving beam of the wireless communication device 10 and the direction of the transmitting beam of the wireless device 20 is greater than the above-specified value, the wireless communication device 10 may perform control (second control) to adjust the direction of the beam with the wireless device 20 without providing a service corresponding to the wireless device 20.

[0039] For example, the control unit 12 of the wireless communication device 10 may make the above determination based on the difference between a beam sector that identifies the transmission beam of the wireless communication device 10 (first transmission beam identification information) and a beam sector that identifies the reception beam of the wireless device 20 transmitted from the wireless device 20 (second reception beam identification information). Alternatively, the control unit 12 of the wireless communication device 10 may make the above determination based on the difference between a beam sector that identifies the reception beam of the wireless communication device 10 (first reception beam identification information) and a beam sector that identifies the transmission beam of the wireless device 20 transmitted from the wireless device 20 (second transmission beam identification information).

[0040] Alternatively, the control unit 12 of the wireless communication device 10 may make the above determination based on the difference between information indicating the direction of the transmitting beam of the wireless communication device 10 (first transmitting beam direction information) and information indicating the direction of the receiving beam of the wireless device 20 transmitted from the wireless device 20 (second receiving beam direction information).

[0041] As described above, in this embodiment, the control unit 12 of the wireless communication device 10 controls the beam direction between itself and the wireless device 20 without providing a service corresponding to the wireless device 20 if the deviation between the beam direction of the wireless communication device 10 and the beam direction of the wireless device 20 is greater than a specified value. On the other hand, the control unit 12 of the wireless communication device 10 controls the provision of a service corresponding to the wireless device 20 if the deviation between the beam direction of the wireless communication device 10 and the beam direction of the wireless device 20 is less than or equal to a specified value.

[0042] Through this control system, if reflection effects are anticipated, the wireless communication device 10 will not provide services to the wireless device 20. Services will only be provided from the wireless communication device 10 to the wireless device 20 if no reflection effects are anticipated. This allows for the provision of appropriate services tailored to the communication partner while keeping implementation costs down.

[0043] [Second Embodiment] Figure 5 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 5, 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.

[0044] As shown in Figure 5, the wireless communication system 2 of this embodiment includes a wireless communication device 10 and wireless equipment 20, as well as a plurality of image transmission systems 30 and a monitor 40 (display device). The wireless communication device 10 and the plurality of image transmission systems 30 are installed on the station platform HM, while the wireless equipment 20 and monitor 40 are installed on the train TR (train formation).

[0045] 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 5, 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 5 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.

[0046] 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.

[0047] 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.

[0048] When a train TR enters (or departs from) track 1, the wireless communication device 10 controls the beam BM formed by the phased array antenna 11 so that it is directed towards the wireless device 20 installed on the train TR entering (or departing from) track 1. The wireless communication device 10 then provides a service to transmit the image input to port P1 toward the wireless device 20 located in the direction of the beam BM.

[0049] When a train TR enters track 2 (or departs from track 2), the wireless communication device 10 controls the beam BM formed by the phased array antenna 11 so that it is directed towards the wireless device 20 installed on the train TR entering track 2 (or the train TR departing from track 2). The wireless communication device 10 then provides a service to transmit the image input to port P2 toward the wireless device 20 located in the direction of the beam BM.

[0050] The 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. The monitor 40 is installed, for example, in the driver's cab of a train TR.

[0051] When train TR enters track 1, as described above, the wireless communication device 10 controls beam BM to point towards the wireless device 20 of train TR entering track 1, and provides the wireless device 20 with a service to transmit the image input to port P1. As a result, the monitor 40 of train TR entering track 1 displays the image captured by the image transmission system 30a (an image of track 1 of platform HM where train TR is entering).

[0052] When train TR enters track 2, as described above, the wireless communication device 10 controls beam BM to point towards the wireless device 20 of train TR entering track 2, and provides the wireless device 20 with a service to transmit the image input to port P2. As a result, the monitor 40 of train TR entering track 2 displays the image captured by the image transmission system 30b (an image of track 2 of platform HM where train TR is entering).

[0053] Figure 6 is an explanatory diagram illustrating the case where reflection has an effect in the second embodiment of the present invention. As shown in Figure 6, if there is a structure X on the track 1 side of platform HM, the beam BM of the wireless communication device 10 is reflected by the structure X and can be received by the wireless equipment 20 of the train TR entering track 2. Since the direction of the beam BM of the wireless communication device 10 is toward the structure X located on the track 1 side, the wireless communication device 10 provides a service to the wireless equipment 20 installed on the train TR entering track 2 to transmit the image input to port P1. As a result, a problem occurs in which the monitor 40 of the train TR entering track 2 displays the image taken by the image transmission system 30a (an image of track 1 on the opposite side of platform HM).

[0054] In this embodiment, similar to the first embodiment, if the discrepancy between the beam direction of the wireless communication device 10 and the beam direction of the wireless device 20 is greater than a specified value, the control unit 12 of the wireless communication device 10 performs control to adjust the beam direction with the wireless device 20 without providing a service corresponding to the wireless device 20. By performing such control, the occurrence of the above-mentioned malfunction is prevented.

[0055] Next, the operation of the wireless communication system according to the second embodiment of the present invention will be described. For the sake of simplicity, the following explanation will use as an example the case in which a train TR enters track 2 of platform HM, when a structure X exists on track 1 of platform HM, as shown in Figure 6.

[0056] Figure 7 is a timing chart illustrating the first operation of a wireless communication system according to a second embodiment of the present invention. This example of operation is an example of determining whether the deviation between the beam direction of the wireless communication device 10 and the beam direction of the wireless device 20 is greater than a specified value, based on the difference between the transmitting beam sector of the wireless communication device 10 and the receiving beam sector of the wireless device 20.

[0057] The wireless communication device 10 transmits beacons by broadcast at regular time intervals (step S11). When the train TR enters platform 2 of platform HM, the beacon transmitted from the wireless communication device 10 is received by the wireless device 20 installed on the train TR. Upon receiving the beacon, the wireless device 20 checks the SSID, etc., and then sends an association request to the wireless communication device 10 (step S12).

[0058] When the wireless communication device 10 receives an association request transmitted from the wireless device 20, it sends an ACK (ACKnowledgement) to the wireless device 20 (step S13). This establishes an association between the wireless communication device 10 and the wireless device 20. Once the association is established, the wireless communication device 10 and the wireless device 20 perform a search for the transmit beam sector (step S14). For example, when receiving, the wireless communication device 10 and the wireless device 20 enter a quasi-omnidirectional state and perform the process of searching for the transmit beam sector.

[0059] 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 the wireless device 20 (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. The optimal beam sector is the beam sector in which the received power is maximized on the wireless device 20 side, and assuming there are no reflection effects, the transmit and receive beam directions (directions in which the main lobe appears) of the wireless communication device 10 and the wireless device 20 are directly facing each other. The position of the wireless device 20 changes according to the movement of the train TR. Therefore, the search for the optimal transmit and receive beam sector continues at least until the train TR stops.

[0060] Once the optimal transmit and receive beam sectors are found, the wireless device 20 notifies the wireless communication device 10 of its receive beam sector (step S16). The wireless communication device 10 calculates the difference between the transmit beam sector of the wireless communication device 10 (first beam identification information, first transmit beam identification information) and the receive beam sector of the wireless device 20 notified by the wireless device 20 (second beam identification information, second receive beam identification information). Based on this difference, it determines whether the deviation between the direction of the transmit beam of the wireless communication device 10 and the direction of the receive beam of the wireless device 20 is greater than a specified value. In other words, it determines whether or not there is an effect of reflection (step S17).

[0061] If the wireless communication device 10 determines that there is an effect of reflection, it repeats the processing in steps S15 to S17 with the wireless device 20. Therefore, if it determines that there is an effect of reflection, the service corresponding to the wireless device 20 installed on the train TR entering track 2 will not be provided.

[0062] In contrast, the wireless communication device 10 repeatedly performs the processes in steps S15 to S17 with the wireless device 20, and the transmitting beam of the wireless communication device 10 and the receiving beam of the wireless device 20 come to the relationship shown in Figure 4(a). Then, since the deviation becomes less than or equal to the specified value, the wireless communication device 10 determines in step S17 that there is no effect of reflection.

[0063] If it is determined that there is no influence from reflection, the wireless communication device 10 switches to the image transmission system corresponding to the transmission beam sector (step S18). Specifically, the wireless communication device 10 starts providing a service to transmit the image input to port P2 toward the wireless device 20 located in the direction of beam BM. Specifically, the wireless communication device 10 converts the image data input to port P2 into a data frame and transmits it to the wireless device 20 (step S19).

[0064] When the wireless device 20 receives a data frame transmitted from the wireless communication device 10, it sends an ACK (step S20). Then, the wireless device 20 outputs the received image data to the monitor 40 (step S21). As a result, the images captured by the camera group 31b of the image transmission system 30b are displayed on the monitor 40 installed on the train TR.

[0065] In the example shown in Figure 7, the wireless device 20 transmitted its received beam sector to the wireless communication device 10. The wireless communication device 10 then calculated the difference between its transmitted beam sector (first beam identification information, first transmitted beam identification information) and the received beam sector of the wireless device 20 (second beam identification information, second received beam identification information), and based on this difference, it determined whether the deviation between the direction of the transmitted beam of the wireless communication device 10 and the direction of the received beam of the wireless device 20 was greater than a specified value.

[0066] However, the wireless device 20 may transmit its transmitting beam sector to the wireless communication device 10. The wireless communication device 10 may then calculate the difference between its received beam sector (first beam identification information, first received beam identification information) and the transmitted beam sector (second beam identification information, second transmitted beam identification information) of the wireless device 20, and based on this difference, determine whether the deviation between the direction of the received beam of the wireless communication device 10 and the direction of the transmitted beam of the wireless device 20 is greater than a specified value.

[0067] Furthermore, it is possible to determine whether the discrepancy between the direction of the transmitting beam of the wireless communication device 10 and the direction of the receiving beam of the wireless device 20 is greater than a specified value, and also whether the discrepancy between the direction of the receiving beam of the wireless communication device 10 and the direction of the transmitting beam of the wireless device 20 is greater than a specified value. If at least one of the former discrepancy and the latter discrepancy is greater than a specified value, the wireless communication device 10 may perform control (second control) to adjust the beam direction with the wireless device 20 without providing a service corresponding to the wireless device 20.

[0068] Figure 8 is a timing chart illustrating the second operation of a wireless communication system according to a second embodiment of the present invention. This operation example is an example of operation in which a determination is made as to whether the deviation between the beam direction of the wireless communication device 10 and the beam direction of the wireless device 20 is greater than a specified value, based on the difference between the beam direction of the transmitting beam of the wireless communication device 10 and the beam direction of the receiving beam of the wireless device 20. This operation example is, for example, an example of operation when the beamtable BT used in the wireless communication device 10 and the beamtable BT used in the wireless device 20 are different.

[0069] In this example, the wireless communication device 10 transmits beacons by broadcast at regular time intervals (step S11). When the wireless device 20 installed on the train TR that has entered track 2 receives the beacon, it checks the SSID and other information and then sends an association request to the wireless communication device 10 (step S12).

[0070] When the wireless communication device 10 receives an association request transmitted from the wireless device 20, it sends an ACK to the wireless device 20 (step S13). This establishes an association between the wireless communication device 10 and the wireless device 20, and a search for the transmit beam sector is performed between the wireless communication device 10 and the wireless device 20 (step S14). After the search for the transmit beam sector is completed, the search for the optimal transmit and receive beam sector is performed between the wireless communication device 10 and the wireless device 20 (step S15).

[0071] Once the optimal transmit and receive beam sectors are found, the wireless device 20 uses the beamtable BT to convert the received beam sector into the direction of the received beam (step S31). The wireless device 20 then notifies the wireless communication device 10 of the converted direction of the received beam of the wireless device 20 (step S32). The wireless communication device 10 calculates the difference between the direction of the transmit beam of the wireless communication device 10 (first beam direction information, first transmit beam direction information) and the direction of the received beam of the wireless device 20 notified by the wireless device 20 (second beam direction information, second receive beam direction information). Based on this difference, it determines whether the discrepancy between the direction of the transmit beam of the wireless communication device 10 and the direction of the received beam of the wireless device 20 is greater than a specified value. In other words, it determines whether or not there is an effect of reflection (step S33).

[0072] If the wireless communication device 10 determines that there is an effect of reflection, it repeats the processing in steps S15, S31 to S33 with respect to the wireless equipment 20. Therefore, if it is determined that there is an effect of reflection, the service corresponding to the wireless equipment 20 installed on the train TR entering track 2 will not be provided.

[0073] In response to this, the wireless communication device 10 repeatedly performs the processes in steps S15, S31 to S33 with the wireless device 20, and the transmitting beam of the wireless communication device 10 and the receiving beam of the wireless device 20 come to the relationship shown in Figure 4(a). Then, since the deviation becomes less than or equal to the specified value, the wireless communication device 10 determines in step S33 that there is no effect of reflection.

[0074] If it is determined that there is no effect of reflection, the wireless communication device 10 switches to the image transmission system corresponding to the transmission beam sector, as in the first operation example (step S18). Specifically, the wireless communication device 10 starts providing a service to transmit the image input to port P2 toward the wireless device 20 located in the direction of beam BM. Specifically, the wireless communication device 10 converts the image data input to port P2 into a data frame and transmits it to the wireless device 20 (step S19).

[0075] When the wireless device 20 receives a data frame transmitted from the wireless communication device 10, it sends an ACK (step S20). Then, the wireless device 20 outputs the received image data to the monitor 40 (step S21). As a result, the images captured by the camera group 31b of the image transmission system 30b are displayed on the monitor 40 installed on the train TR.

[0076] In the example shown in Figure 8, the wireless device 20 transmitted the direction of its receiving beam to the wireless communication device 10. The wireless communication device 10 then calculated the difference between the direction of its transmitting beam (first beam direction information, first transmitting beam direction information) and the direction of the receiving beam of the wireless device 20 (second beam direction information, second receiving beam direction information). Based on this difference, it determined whether the discrepancy between the direction of the transmitting beam of the wireless communication device 10 and the direction of the receiving beam of the wireless device 20 was greater than a specified value.

[0077] However, the wireless device 20 may transmit the direction of its transmitting beam to the wireless communication device 10. The wireless communication device 10 may then calculate the difference between the direction of its receiving beam (first beam direction information, first receiving beam direction information) and the direction of the transmitting beam of the wireless device 20 (second beam direction information, second transmitting beam direction information), and based on this difference, determine whether the discrepancy between the direction of the receiving beam of the wireless communication device 10 and the direction of the transmitting beam of the wireless device 20 is greater than a specified value.

[0078] Furthermore, similar to the first example of operation, it is also possible to determine whether the discrepancy between the direction of the transmitting beam of the wireless communication device 10 and the direction of the receiving beam of the wireless device 20 is greater than a specified value, and whether the discrepancy between the direction of the receiving beam of the wireless communication device 10 and the direction of the transmitting beam of the wireless device 20 is greater than a specified value. If at least one of the former discrepancy and the latter discrepancy is greater than a specified value, control (second control) to adjust the beam direction with respect to the wireless device 20 may be performed without providing a service corresponding to the wireless device 20.

[0079] Figure 9 is a timing chart illustrating the third operation of a wireless communication system according to a second embodiment of the present invention. This example of operation determines the presence or absence of reflection effects based on the difference between the transmitting beam sector of the wireless communication device 10 and the receiving beam sector of the wireless device 20, as well as the difference between the transmitting beam sector and the receiving beam sector of the wireless device 10, and the difference between the transmitting beam sector and the receiving beam sector of the wireless device 20.

[0080] In this example, the wireless communication device 10 transmits beacons by broadcast at regular time intervals (step S11). When the wireless device 20 installed on the train TR that has entered track 2 receives the beacon, it checks the SSID and other information and then sends an association request to the wireless communication device 10 (step S12).

[0081] When the wireless communication device 10 receives an association request transmitted from the wireless device 20, it sends an ACK to the wireless device 20 (step S13). This establishes an association between the wireless communication device 10 and the wireless device 20, and a search for the transmit beam sector is performed between the wireless communication device 10 and the wireless device 20 (step S14). After the search for the transmit beam sector is completed, the search for the optimal transmit and receive beam sector is performed between the wireless communication device 10 and the wireless device 20 (step S15).

[0082] Once the optimal transmit and receive beam sectors are found, the wireless device 20 notifies the wireless communication device 10 of its transmit beam sector and receive beam sector (step S41). The wireless communication device 10 calculates the difference between its transmit beam sector and receive beam sector, as well as the difference between the transmit beam sector and receive beam sector of the wireless device 20. Based on these differences, it then determines whether or not there is an effect of reflection (step S42).

[0083] Furthermore, the wireless communication device 10 calculates the difference between the transmitting beam sector of the wireless communication device 10 (first beam identification information, first transmitting beam identification information) and the receiving beam sector of the wireless device 20 notified by the wireless device 20 (second beam identification information, second receiving beam identification information). Based on this difference, it determines whether the deviation between the direction of the transmitting beam of the wireless communication device 10 and the direction of the receiving beam of the wireless device 20 is greater than a specified value. In other words, it determines whether or not there is an effect of reflection (step S43).

[0084] If the wireless communication device 10 determines that there is an effect of reflection in at least one of step S42 and step S43, it repeats the processing in steps S15, S41 to S43 with respect to the wireless equipment 20. Therefore, if it is determined that there is an effect of reflection, the service corresponding to the wireless equipment 20 installed on the train TR entering track 2 will not be provided.

[0085] In response to this, the wireless communication device 10 repeatedly performs the processes in steps S15, S41 to S43 with the wireless device 20, and the transmitting beam of the wireless communication device 10 and the receiving beam of the wireless device 20 come to the relationship shown in Figure 4(a). Then, since the deviation becomes less than or equal to the specified value, the wireless communication device 10 determines in steps S42 and S43 that there is no effect of reflection.

[0086] If it is determined that there is no influence from reflection, the wireless communication device 10 switches to the image transmission system corresponding to the transmission beam sector (step S18). Specifically, the wireless communication device 10 starts providing a service to transmit the image input to port P2 toward the wireless device 20 located in the direction of beam BM. Specifically, the wireless communication device 10 converts the image data input to port P2 into a data frame and transmits it to the wireless device 20 (step S19).

[0087] When the wireless device 20 receives a data frame transmitted from the wireless communication device 10, it sends an ACK (step S20). Then, the wireless device 20 outputs the received image data to the monitor 40 (step S21). As a result, the images captured by the camera group 31b of the image transmission system 30b are displayed on the monitor 40 installed on the train TR.

[0088] In the example shown in Figure 9, in step S43, the wireless communication device 10 calculates the difference between the transmitting beam sector of the wireless communication device 10 (first beam identification information, first transmitting beam identification information) and the receiving beam sector of the wireless device 20 (second beam identification information, second receiving beam identification information). Based on this difference, it determines whether the deviation between the direction of the transmitting beam of the wireless communication device 10 and the direction of the receiving beam of the wireless device 20 is greater than a specified value.

[0089] However, in step S43, the wireless communication device 10 may calculate the difference between the received beam sector of the wireless communication device 10 (first beam identification information, first received beam identification information) and the transmitted beam sector of the wireless device 20 (second beam identification information, second transmitted beam identification information), and based on this difference, determine whether the deviation between the direction of the received beam of the wireless communication device 10 and the direction of the transmitted beam of the wireless device 20 is greater than a specified value.

[0090] Furthermore, in the example shown in Figure 9, in step S41, the wireless device 20 notifies the wireless communication device 10 of the transmitting beam sector and the receiving beam sector of the wireless device 20, and the wireless communication device 10 determines whether or not there is an effect of reflection based on the transmitting beam sector and the receiving beam sector. However, in step S41 shown in Figure 9, the wireless device 20 may also notify the wireless communication device 10 of the direction of the transmitting beam and the direction of the receiving beam of the wireless device 20, and the wireless communication device 10 may determine whether or not there is an effect of reflection based on the direction of the transmitting beam and the direction of the receiving beam.

[0091] As described above, in this embodiment, the wireless communication device 10 is installed on the platform HM, and the wireless device 20 that communicates wirelessly with the wireless communication device 10 is installed on the train TR. The wireless communication device 10 is configured to adjust the beam direction with the wireless device 20 without providing a service corresponding to the wireless device 20 if the deviation between the beam direction of the wireless communication device 10 and the beam direction of the wireless device 20 is greater than a specified value. On the other hand, the wireless communication device 10 is configured to provide a service corresponding to the wireless device 20 if the deviation between the beam direction of the wireless communication device 10 and the beam direction of the wireless device 20 is less than or equal to a specified value.

[0092] Through this control system, if reflection effects are anticipated, the wireless communication device 10 will not provide services to the wireless device 20. Services will only be provided from the wireless communication device 10 to the wireless device 20 if no reflection effects are anticipated. This allows for the provision of appropriate services tailored to the communication partner while keeping implementation costs down.

[0093] For example, if the influence of reflection from structure X shown in Figure 6 is considered, the image captured by the camera group 31a of the image transmission system 30a will not be displayed on the monitor 40 installed on the train TR entering track 2. In contrast, as shown in Figure 5, if the influence of reflection is not considered, the image captured by the camera group 31a of the image transmission system 30a will be displayed on the monitor 40 installed on the train TR entering track 1. Thus, in this embodiment, it is possible to provide an appropriate image of the platform HM to the train TR entering the platform with the platform HM.

[0094] 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 service provided in the second embodiment above displayed an image of the platform HM track to which the train TR was entering on a monitor 40 installed on the train TR entering the platform HM track. However, conversely, the service may also be provided to display an image of the train TR entering the platform HM track (for example, an image inside the train TR) on a monitor installed for each platform HM track.

[0095] Furthermore, if only two tracks, Track 1 and Track 2, exist at the platform HM, and it is determined that the effects of reflection continue, the wireless communication device 10 may provide an image of the track opposite to the track on which the train TR is expected to enter. For example, in the example shown in Figure 6, if the wireless communication device 10 determines that the effects of reflection continue, it may provide an image of Track 2, which is opposite to Track 1, on which the train TR is expected to enter. This makes it possible to provide an image of Track 2 to the wireless equipment 20 of the train TR entering Track 2 via a path affected by reflection from structure X. [Explanation of Symbols]

[0096] 1,2... Wireless communication system, 10... Wireless communication device, 11... Phased array antenna, 20... Wireless equipment, 40... Display device, HM... Platform, TR... Train formation

Claims

1. A wireless communication system comprising a wireless communication device that supports multiple services, and a wireless device that communicates wirelessly with the wireless communication device and receives services provided by the wireless communication device, The wireless communication device performs a first control to provide a service corresponding to the wireless device when the deviation between the beam direction of the device and the beam direction of the wireless device is less than or equal to a specified value. Wireless communication system.

2. The wireless communication system according to claim 1, wherein if the discrepancy between the direction of the beam of the wireless device and the direction of the beam of the wireless device is greater than the specified value, the wireless communication device performs a second control to adjust the direction of the beam between itself and the wireless device without providing a service corresponding to the wireless device.

3. The wireless communication system according to claim 1, wherein the wireless communication device determines whether the deviation between the direction of the beam of the wireless device and the direction of the beam of the wireless device is greater than the specified value, based on the difference between first beam identification information that identifies the beam of the wireless device and second beam identification information that identifies the beam of the wireless device transmitted from the wireless device.

4. The wireless communication system according to claim 1, wherein the wireless communication device determines whether the discrepancy between the beam direction of the wireless device and the beam direction of the wireless device is greater than the specified value, based on the difference between first beam direction information indicating the beam direction of the device and second beam direction information indicating the beam direction of the wireless device transmitted from the wireless device.

5. The wireless communication device performs the second control when at least one of the discrepancies between the direction of its transmitting beam and the direction of the receiving beam of the wireless device, and the discrepancies between the direction of its receiving beam and the direction of the transmitting beam of the wireless device, is greater than the specified value. The wireless communication system according to claim 2.

6. The wireless communication device determines whether the discrepancy between the direction of its own transmitting beam and the direction of the wireless device's receiving beam is greater than the specified value, based on the difference between first transmitting beam identification information that identifies the transmitting beam of its own device and second receiving beam identification information that identifies the receiving beam of the wireless device transmitted from the wireless device. Based on the difference between first received beam identification information that identifies the received beam of the device itself and second transmitted beam identification information that identifies the transmitted beam of the wireless device transmitted from the wireless device, it is determined whether the deviation between the direction of the received beam of the device itself and the direction of the transmitted beam of the wireless device is greater than the specified value. The wireless communication system according to claim 5.

7. The wireless communication device determines whether the discrepancy between the direction of its own transmitting beam and the direction of the receiving beam of the wireless device is greater than the specified value, based on the difference between first transmitting beam direction information indicating the direction of its own transmitting beam and second receiving beam direction information indicating the direction of the receiving beam of the wireless device transmitted from the wireless device. Based on the difference between first received beam direction information indicating the direction of the received beam of the device itself and second transmitted beam direction information indicating the direction of the transmitted beam of the wireless device transmitted from the wireless device, it is determined whether the discrepancy between the direction of the received beam of the device itself and the direction of the transmitted beam of the wireless device is greater than the specified value. The wireless communication system according to claim 5.

8. 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 1.

9. 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 8.

10. The wireless communication device provides a service that transmits an image of the platform corresponding to the platform number to 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 9.

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