Wireless communication device, wireless communication method, and program

Abstract

This wireless communication device comprises: a plurality of wireless units that connect to a plurality of base stations via wireless links for each base station; a control unit that selects a wireless link having high communication quality from among the wireless links for each base station; and a transmission unit that, via the selected wireless link, transmits, to at least one of a prescribed device for selecting a base station to relay a downlink data signal and a device subordinate to the prescribed device, an uplink dummy signal including identification information pertaining to a user device to which the downlink data signal is to be transmitted. When the selection of the wireless link for each base station is updated, the transmission unit may, via the selected wireless link, transmit the uplink dummy signal to at least one of the prescribed device and the device subordinate to the prescribed device.

Description

Wireless Communication Device, Wireless Communication Method, and Program

[0001] The present invention relates to a wireless communication device, a wireless communication method, and a program.

[0002] In a wireless communication system in which a plurality of base stations are arranged in a communication area, a wireless communication device may communicate with a higher-level device via a wireless link selected from among the wireless links for each base station. Here, the wireless communication device selects a wireless link with higher communication quality from among the wireless links for each base station.

[0003] Even when the wireless communication device moves within the communication area, the wireless communication device needs to maintain communication with the higher-level device. In a mobile communication system, the communication quality of the wireless link for each base station is constantly measured. The wireless communication device pre-selects a wireless link to be the switching destination before switching the signal path to a wireless link with higher communication quality. For this reason, the wireless communication device can switch the signal path in a short time.

[0004] On the other hand, in wireless communication that does not assume the movement of a wireless communication device (for example, wireless LAN (Local Area Network)), the wireless communication device searches for a wireless link to be the switching destination after the wireless link between the wireless communication device and the base station is disconnected. For this reason, a communication interruption occurs according to the time required to search for a wireless link to be the switching destination.

[0005] For the purpose of suppressing the occurrence of such a communication interruption, a single wireless communication device may be provided with a plurality of wireless units (see Non-Patent Documents 1 and 2). The plurality of wireless units are connected to a plurality of base stations via the wireless links for each base station. As a result, a plurality of wireless links are formed between the single wireless communication device and the plurality of base stations, and the occurrence of a communication interruption is suppressed by site diversity control using these wireless links.

[0006] NTT Press Release, “The world's first uninterrupted large-capacity wireless transmission in a high-speed mobile environment using 60GHz band wireless communication”, [online], Feb. 2022, Nippon Telegraph and Telephone Corporation, [Retrieved October 28, 2024], Internet<URL: https: / / group.ntt / en / newsrelease / 2022 / 02 / 25 / 220225a.html> T. Iwakuni et al., “Handover Experiment of 60-GHz-Band Wireless LAN in over 200-km / h High-Speed ​​Mobility Environment”, IEICE Trans. Communication, Oct. 2022, Vol.E106-B, No.4, pp.384-391.

[0007] Figure 15 shows an example configuration of a wireless communication system 10. The wireless communication system 10 comprises a wireless communication device 20, a plurality of base stations 30, a host switch 40, and a host device 50. The wireless communication device 20 comprises a control device 201, a user device 202, and a plurality of wireless units 203. The host switch 40 is a LAN switch on the network side. The host device 50 is a communication device on the network side.

[0008] In site diversity control led by the wireless communication device 20, the control device 201 measures the communication quality of the radio link 60 between the base station 30 and the radio unit 203 for each base station 30. The control device 201 selects the radio link 60 with higher communication quality. The control device 201 switches the uplink data signal path to the selected radio link 60. The user device 202 communicates with the host device 50 via the control device 201, the selected radio link 60, the base station 30, and the host switch 40.

[0009] When the upper-level switch 40 acquires an uplink data signal from the user device 202, the upper-level switch 40 selects a base station 30 that has the wireless link 60 through which the acquired uplink data signal traveled, so that the downlink data signal also travels through that same wireless link 60. The upper-level switch 40 then forwards the downlink data signal from the upper-level device 50 to the selected base station 30.

[0010] If the upper-level switch 40 has acquired an uplink data signal before the upper-level device 50 transmits a downlink data signal, the upper-level switch 40 can detect that the selection of the wireless link 60 has been updated (that the path of the uplink data signal has switched) before transferring the downlink data signal from the upper-level device 50. The downlink data signal is acquired by the user device 202 via the wireless link 60, which has a higher communication quality.

[0011] However, if the upstream switch 40 has not yet acquired the uplink data signal from the user device 202, even though the selection of the wireless link 60 has been updated by the control device 201, the upstream switch 40 cannot detect that the selection of the wireless link 60 has been updated before transferring the downlink data signal from the upstream device 50. As a result, the upstream switch 40 selects the base station 30 that has the wireless link 60, so that the downlink data signal also uses the same wireless link 60 that the uplink data signal used before the selection of the wireless link 60 was updated. Consequently, the downlink data signal from the upstream device 50 is acquired by the user device 202 via the wireless link 60 with low communication quality. Thus, there is a problem in site diversity control led by the wireless communication device 20, where the communication quality of the downlink data signal cannot be improved.

[0012] In view of the above circumstances, the present invention aims to provide a wireless communication device, a wireless communication method, and a program that can improve the communication quality of downlink data signals in site diversity control led by a wireless communication device.

[0013] One aspect of the present invention is a wireless communication device comprising: a plurality of wireless units connected to a plurality of base stations via wireless links for each base station; a control unit that selects a wireless link with higher communication quality from among the wireless links for each base station; a predetermined device that selects a base station that relays the downlink data signal, and a transmitting unit that transmits an uplink dummy signal containing identification information of a user device to which a downlink data signal is to be transmitted, to at least one of the devices under the predetermined device, via the selected wireless link.

[0014] One aspect of the present invention is a wireless communication method performed by a wireless communication device, comprising the steps of: connecting to a plurality of base stations via a wireless link for each base station; selecting a wireless link with higher communication quality from among the wireless links for each base station; and transmitting an uplink dummy signal containing identification information of a user device to which a downlink data signal is to be transmitted to at least one of a predetermined device that selects the base station that relays the downlink data signal, and a device under the control of the predetermined device, via the selected wireless link.

[0015] One aspect of the present invention is a program that causes a computer to perform the following steps: connect to a plurality of base stations via a wireless link for each base station; select a wireless link with higher communication quality from among the wireless links for each base station; and transmit an uplink dummy signal containing identification information of a user device to which a downlink data signal is to be transmitted to at least one of a predetermined device that selects a base station to relay the downlink data signal, and a device under the control of the predetermined device, via the selected wireless link.

[0016] The present invention makes it possible to improve the communication quality of downlink data signals in site diversity control led by wireless communication devices.

[0017] This is a diagram showing an example configuration of the wireless communication system in the first embodiment. This is a flowchart showing an example operation of the control device in the first embodiment. This is a flowchart showing an example operation of the wireless communication system in the first embodiment. This is a diagram showing an example configuration of the wireless communication system in the second embodiment. This is a flowchart showing an example operation of the control device in the second embodiment. This is a diagram showing an example configuration of the wireless communication system in the third embodiment. This is a flowchart showing an example operation of the control device in the third embodiment. This is a diagram showing an example configuration of the wireless communication system in the fourth embodiment. This is a flowchart showing an example operation of the control device in the fourth embodiment. This is a diagram showing an example configuration of the wireless communication system in the fifth embodiment. This is a flowchart showing an example operation of the control device in the fifth embodiment. This is a diagram showing an example configuration of the wireless communication system in the sixth embodiment. This is a flowchart showing an example operation of the control device in the sixth embodiment. This is a diagram showing an example hardware configuration of the wireless communication device in each embodiment. This is a diagram showing an example configuration of the wireless communication system.

[0018] Embodiments of the present invention will be described in detail with reference to the drawings. (First Embodiment) Figure 1 is a diagram showing an example of the configuration of a wireless communication system 1a in the first embodiment. The wireless communication system 1a is a system that performs communication via a plurality of wireless links. The wireless communication system 1a comprises a wireless communication device 2a, a plurality of base stations 3, a host switch 4, and a host device 5. The wireless communication device 2a comprises a control device 21a and a plurality of wireless units 22. The control device 21a comprises a user device 211, a transmitting unit 212, and a control unit 213. The transmitting unit 212 and the control unit 213 may be integrated.

[0019] Signals whose destination is under the upper-level switch 4 pass through the upper-level switch 4. The wireless communication system 1a may include, for example, a control server connected to the upper-level switch 4 as a device under the upper-level switch 4 (for example, upper-level device 5). This control server may, for example, control the operation of the wireless communication device 2a. The wireless communication system 1a may also include a proxy server connected to the upper-level switch 4 as a device under the upper-level switch 4 (for example, upper-level device 5).

[0020] The wireless communication device 2a is a system that communicates with a higher-level device 5 via multiple wireless links 6. Here, the wireless communication device 2a performs site diversity control using the wireless links 6 for each base station 3. The wireless communication device 2a may move within a communication area where multiple base stations 3 are located.

[0021] The control device 21a is a device that controls the selection (switching) of the wireless link 6 as site diversity control. The user device 211 is the user's communication device. The user device 211 is connected to the control unit 213. The user device 211 is assigned identification information as the source address of the uplink data signal. The identification information is, for example, the MAC (Media Access Control address) address. The user device 211 transmits the uplink data signal to the host device 5 via the control unit 213. The user device 211 receives the downlink data signal from the host device 5 via the control unit 213. The identification information of the user device 211 may be included in this downlink data signal as the destination address of the downlink data signal.

[0022] When the transmitter 212 is notified by the control unit 213 that the selection of the wireless link 6 has been updated, it transmits an uplink dummy signal containing the identification information of the user device 211 via the control unit 213 and the selected wireless link 6 to at least one of the devices that select the base station 3 to relay the downlink data signal, and the devices under that predetermined device (unicast transmission). The predetermined device is, for example, a higher-level switch 4. The devices under this predetermined device are higher-level devices 5 under the higher-level switch 4, which may be, for example, a control server or a proxy server.

[0023] The control unit 213 selects a radio link 6 with higher communication quality from among the radio links 6 for each base station 3. If the control unit 213 updates the selection of radio link 6, it notifies the transmission unit 212 that the selection of radio link 6 has been updated. The control unit 213 transmits the uplink dummy signal obtained from the transmission unit 212 to a predetermined device (e.g., a higher-level switch 4) that selects a base station 3 to relay the downlink data signal via the selected radio link 6. The control unit 213 may also transmit the uplink dummy signal obtained from the transmission unit 212 to a device under the control of that predetermined device (e.g., a higher-level device 5).

[0024] N (where N is an integer greater than or equal to 2) radio units 22 are connected to N base stations 3 from a plurality of base stations 3 via radio links 6 for each base station 3. The radio units 22 transmit the uplink dummy signal acquired from the control unit 213 to a predetermined device (e.g., a higher-level switch 4) via the radio link 6 selected by the control unit 213. The radio units 22 may also transmit the uplink dummy signal to a device under the control of that predetermined device (e.g., a higher-level device 5).

[0025] When base station 3 receives an uplink data signal from the radio communication device 2a via its own radio link 6, it forwards the uplink data signal to the upstream switch 4. When base station 3 receives an uplink dummy signal from the radio communication device 2a via its own radio link 6, it forwards the uplink dummy signal to the upstream switch 4. When base station 3 receives a downlink data signal from the upstream switch 4, it forwards the downlink data signal to the radio communication device 2a via its own radio link 6.

[0026] The upstream switch 4 is a network-side switch, for example, a LAN switch. When the upstream switch 4 receives an uplink dummy signal from the wireless communication device 2a, it detects that the selection of wireless link 6 has been updated by the wireless communication device 2a. That is, based on the source address of the uplink dummy signal (for example, the MAC address of the user device 211), the upstream switch 4 detects that the user device 211 is located at the end of the wireless link 6 through which the uplink data signal has passed.

[0027] The higher-level switch 4 selects a base station 3 to relay the downlink data signal. Here, the higher-level switch 4 selects a base station 3 that has the radio link 6 through which the acquired uplink dummy signal has passed, so that the downlink data signal also passes through that radio link 6. The higher-level switch 40 forwards the downlink data signal from the higher-level device 5 to the selected base station 3.

[0028] The higher-level device 5 is a network-side communication device. The higher-level device 5 communicates with the user device 211 via the higher-level switch 4, the base station 3, the selected wireless link 6, and the control unit 213. The higher-level device 5 transmits a downlink data signal containing the user device 211's identification information (destination address of the downlink data signal) to the higher-level switch 4. The higher-level device 5 receives an uplink data signal containing the user device 211's identification information (source address of the uplink data signal) from the higher-level switch 4. The higher-level device 5 may perform predetermined signal processing on the uplink data signal.

[0029] Next, an example of the operation of the wireless communication system 1a will be described. Figure 2 is a flowchart showing an example of the operation of the control device 21a in the first embodiment. The control unit 213 determines whether or not the selection of wireless link 6 has been updated (step S101). If the selection of wireless link 6 has not been updated (step S101: NO), the control unit 213 re-executes step S101 by, for example, performing short-period polling. If the control unit 213 determines that the selection of wireless link 6 has been updated, it may immediately proceed to step S102 using an event trigger.

[0030] If the selection of wireless link 6 is updated (step S101: YES), the control unit 213 notifies the transmission unit 212 that the selection of wireless link 6 has been updated. The transmission unit 212 transmits an uplink dummy signal containing the identification information of the user device 211 (the source address of the uplink data signal) to at least one of a predetermined device (e.g., a higher-level switch 4) that selects a base station 3 to relay the downlink data signal, and to a device under that predetermined device, via the control unit 213 and the selected wireless link 6. That is, the control unit 213 transmits the uplink dummy signal via the selected wireless link 6 to at least one of a predetermined device and a device under that predetermined device (step S102). The transmission unit 212 and the control unit 213 return to step S101.

[0031] Figure 3 is a flowchart illustrating an example of the operation of the wireless communication system 1a in the first embodiment. N wireless units 22 connect to N base stations 3 via wireless links 6 for each base station 3 (step S201). The control unit 213 selects a wireless link 6 with higher communication quality from among the wireless links 6 for each base station 3 (step S202). Step S203 is the same as step S101 illustrated in Figure 2. That is, the control unit 213 determines whether or not the selection of wireless link 6 has been updated (step S203). If the selection of wireless link 6 has not been updated (step S203: NO), the control unit 213 proceeds to step S205.

[0032] If it is determined that the selection of wireless link 6 has been updated (step S203: YES), the control unit 213 notifies the transmission unit 212 that the selection of wireless link 6 has been updated. The transmission unit 212 transmits an uplink dummy signal containing the identification information of the user device 211 to the control unit 213. The control unit 213 transmits the uplink dummy signal via the selected wireless link 6 to at least one of the predetermined device that selects the base station 3 (e.g., the upstream switch 4) and the device under that predetermined device (e.g., the upstream device 5) (step S204).

[0033] The control unit 213 determines whether or not an uplink data signal has been acquired from the user device 211 (step S205). If it is determined that an uplink data signal has not been acquired from the user device 211 (step S205: NO), the control unit 213 returns to step S201.

[0034] If it is determined that an uplink data signal has been acquired from the user device 211 (step S205: YES), the control unit 213 transmits the acquired uplink data signal to the host device 5 via the radio unit 22, the selected radio link 6, the base station 3, and the host switch 4 (step S206). The control unit 213 returns to step S201.

[0035] As described above, the multiple radio units 22 connect to the multiple base stations 3 via a radio link 6 for each base station 3. The control unit 213 selects the radio link 6 with higher communication quality from among the radio links 6 for each base station 3. When the selection of radio link 6 is updated, the transmission unit 212 transmits (unicast) an uplink dummy signal (control signal) containing identification information (e.g., MAC address) of the user device 211 to which the downlink data signal will be transmitted, to at least one of a predetermined device (e.g., a higher-level switch 4) and a device under that predetermined device (e.g., a higher-level device 5) via the control unit 213 and the selected radio link 6. The higher-level switch 4 is, for example, a LAN switch. The higher-level device 5 is, for example, a control server or a proxy server.

[0036] In this way, when the selection of wireless link 6 is updated by the control unit 213, the control unit 213 transmits an uplink dummy signal, including the source address of the uplink data signal (for example, the MAC address of the user device 211), to at least one of a predetermined device (for example, a higher-level switch 4) and a device under that predetermined device (for example, a higher-level device 5) via the newly selected wireless link 6. The predetermined device detects that the selection of a wireless link 6 with higher communication quality has been changed. That is, based on the source address of the uplink data signal, the predetermined device detects that the user device 211 is located at the end of the wireless link 6 through which the uplink data signal has passed. The higher-level switch 4 selects a base station 3 that has the wireless link 6 so that the downlink data signal also passes through that wireless link 6. The higher-level switch 4 forwards the downlink data signal from the higher-level device 5 to the base station 3 that has the wireless link 6.

[0037] This makes it possible to improve the communication quality of downlink data signals in site diversity control led by wireless communication equipment. For example, even if the downlink data signal is transferred to the upper-level switch 4 before the uplink data signal is transferred to the upper-level switch 4, the path of the downlink data signal is switched in advance based on the uplink dummy signal, making it possible to improve the communication quality of the downlink data signal.

[0038] (Second Embodiment) In the second embodiment, the main difference from the first embodiment is that the user device is located outside the control device. The second embodiment will be explained focusing on the differences from the first embodiment.

[0039] Figure 4 shows an example of the configuration of a wireless communication system 1b in the second embodiment. The wireless communication system 1b comprises a wireless communication device 2b, a plurality of base stations 3, a host switch 4, and a host device 5. The wireless communication device 2b comprises a control device 21b, a plurality of wireless units 22, and a user device 211. The control device 21b comprises a transmitting unit 212, a control unit 213, and an acquisition unit 214.

[0040] The acquisition unit 214 acquires the identification information of the user device 211. Here, the acquisition unit 214 may query the user device 211 for the identification information of the user device 211 via the control unit 213. The acquisition unit 214 may acquire the identification information of the user device 211 from, for example, the operator of the wireless communication system 1b (not shown) via an input device such as a keyboard (not shown). The acquisition unit 214 notifies the transmission unit 212 of the identification information of the user device 211.

[0041] Next, an example of the operation of the wireless communication system 1b will be described. Figure 5 is a flowchart showing an example of the operation of the control device 21b in the second embodiment. The acquisition unit 214 acquires the identification information of the user device 211. The acquisition unit 214 notifies the transmission unit 212 of the identification information of the user device 211 (step S301). Steps S302 and S303 are the same as steps S101 and S102 illustrated in Figure 2.

[0042] As described above, the acquisition unit 214 acquires the identification information of the user device 211. The acquisition unit 214 notifies the transmission unit 212 of the identification information of the user device 211. When the selection of the wireless link 6 is updated, the transmission unit 212 transmits an uplink dummy signal via the control unit 213 and the selected wireless link 6 to at least one of a predetermined device (e.g., a higher-level switch 4) and a device under that predetermined device (e.g., a higher-level device 5). This makes it possible to improve the communication quality of downlink data signals in site diversity control led by wireless communication devices.

[0043] (Third Embodiment) In the third embodiment, the main difference from the first and second embodiments is that multiple user devices are connected under the control device. The third embodiment will be explained focusing on the differences from the first and second embodiments.

[0044] FIG. 6 is a diagram showing a configuration example of the wireless communication system 1c in the third embodiment. The wireless communication system 1c includes a wireless communication device 2c, a plurality of base stations 3, a higher-level switch 4, and a higher-level device 5. The wireless communication device 2c includes a control device 21c, a plurality of wireless units 22, a lower-level switch 23, and M (M is an integer of 2 or more) user devices 211. The control device 21c includes a transmission unit 212, a control unit 213, and an acquisition unit 214.

[0045] The lower-level switch 23 is, for example, a LAN switch on the user device side. The M user devices 211 are connected to the control unit 213 via the lower-level switch 23. The lower-level switch 23 transfers the upstream data signal from the user device 211 to the control unit 213. The lower-level switch 23 may transmit the identification information of each user device 211 to the acquisition unit 214 via the control unit 213. Further, the lower-level switch 23 transfers the downstream data signal including the identification information (transmission destination address of the downstream data signal) of the user device 211 to the user device 211 associated with the identification information.

[0046] Next, an operation example of the wireless communication system 1c will be described. FIG. 7 is a flowchart showing an operation example of the control device 21c in the third embodiment. The acquisition unit 214 acquires the identification information of each user device 211. The acquisition unit 214 notifies the transmission unit 212 of the identification information of each user device 211 (step S301). Step S402 is the same as step S101 illustrated in FIG. 2.

[0047] When the selection of the wireless link 6 is updated (step S402: YES), the control unit 213 notifies the transmission unit 212 that the selection of the wireless link 6 has been updated. The transmission unit 212 transmits an upstream dummy signal including the identification information of the user device 211 to at least one of a predetermined device (for example, the upper switch 4) and a device under the control of the predetermined device (for example, the upper device 5) for each identification information via the control unit 213 and the selected wireless link 6. That is, the control unit 213 transmits the upstream dummy signal to at least one of a predetermined device and a device under the control of the predetermined device for each identification information via the selected wireless link 6 (step S403). The transmission unit 212 and the control unit 213 return the process to step S402.

[0048] As described above, the acquisition unit 214 acquires the identification information of each user device 211. The acquisition unit 214 notifies the transmission unit 212 of the identification information of each user device 211. When the selection of the wireless link 6 is updated, the transmission unit 212 transmits an upstream dummy signal to at least one of a predetermined device and a device under the control of the predetermined device for each identification information via the control unit 213 and the selected wireless link 6. Thereby, in the site diversity control led by the wireless communication device, it is possible to improve the communication quality of the downstream data signal.

[0049] (Fourth Embodiment) In the fourth embodiment, the main difference from the first embodiment is that the upstream dummy signal is broadcast transmitted. In the fourth embodiment, the description will be centered on the differences from the first embodiment.

[0050] FIG. 8 is a diagram showing a configuration example of the wireless communication system 1d in the fourth embodiment. The wireless communication system 1d includes a wireless communication device 2d, a plurality of base stations 3, an upper switch 4, and an upper device 5. The wireless communication device 2d includes a control device 21d and a plurality of wireless units 22. The control device 21d includes a user device 211, a transmission unit 212, a control unit 213, and a discard unit 215.

[0051] The control unit 213 notifies the transmission unit 212 that the selection of wireless link 6 has been updated. The transmission unit 212 broadcasts an uplink dummy signal containing the identification information of the user device 211 (the source address of the uplink data signal) via the control unit 213 and the selected wireless link 6. In other words, the control unit 213 broadcasts the uplink dummy signal via the selected wireless link 6. The upper-level switch 4 acquires the uplink dummy signal. The destination address of the uplink dummy signal indicates that the transmission method of the uplink dummy signal is broadcast. The source address of the uplink dummy signal represents the identification information of the user device 211.

[0052] Upstream dummy signals transmitted via broadcast may return to the control unit 213 via wireless link 6 that has not been selected by the control unit 213. For example, an upstream dummy signal transmitted via wireless link 6-2, which has been selected by the control unit 213, may return to the control unit 213 via wireless link 6-1, which has not been selected. Therefore, the discard unit 215 discards the upstream dummy signals that have been transmitted via broadcast and then returned.

[0053] Next, an example of the operation of the wireless communication system 1d will be described. Figure 9 is a flowchart showing an example of the operation of the control device 21d in the fourth embodiment. Step S501 is the same as step S101 illustrated in Figure 2. If the selection of wireless link 6 is updated (step S501: YES), the control unit 213 notifies the transmission unit 212 that the selection of wireless link 6 has been updated. The transmission unit 212 broadcasts an uplink dummy signal containing the identification information of the user device 211 (source address of the uplink data signal) via the control unit 213 and the selected wireless link 6. That is, the control unit 213 broadcasts the uplink dummy signal via the selected wireless link 6 (step S502).

[0054] The control unit 213 determines whether or not it has received the uplink dummy signal that has returned to the wireless communication device 2d from any of the wireless units 22 (step S503). If the control unit 213 determines that it has not received the returned uplink dummy signal (step S505: NO), the control unit 213 returns to step S501.

[0055] If the control unit 213 determines that it has received the returned uplink dummy signal (step S505: YES), the discard unit 215 discards the uplink dummy signal that has been broadcast and returned (step S504). The control unit 213 returns to step S501.

[0056] As described above, the transmitting unit 212 broadcasts the uplink dummy signal via the control unit 213 and the selected wireless link 6. A predetermined device (e.g., a higher-level switch 4) that selects the base station 3 to relay the downlink data signal acquires the broadcasted uplink dummy signal. Devices under that predetermined device (e.g., a higher-level device 5) may also acquire the broadcasted uplink dummy signal via that predetermined device (e.g., a higher-level switch 4). The discarding unit 215 discards the uplink dummy signal that has been broadcast and returned. This makes it possible to prevent uplink dummy signal transfer loops and improve the communication quality of downlink data signals in site diversity control led by wireless communication devices.

[0057] (Fifth Embodiment) In the fifth embodiment, the main difference from the second embodiment is that the uplink dummy signal is broadcast. The fifth embodiment will be explained focusing on the differences from the second embodiment.

[0058] Figure 10 shows an example of the configuration of a wireless communication system 1e in the fifth embodiment. The wireless communication system 1e comprises a wireless communication device 2e, a plurality of base stations 3, a host switch 4, and a host device 5. The wireless communication device 2e comprises a control device 21e, a plurality of wireless units 22, and a user device 211. The control device 21e comprises a transmission unit 212, a control unit 213, an acquisition unit 214, and a discard unit 215.

[0059] The acquisition unit 214 acquires the identification information of the user device 211. The acquisition unit 214 notifies the transmission unit 212 of the identification information of the user device 211. The transmission unit 212 broadcasts an uplink dummy signal via the control unit 213 and the selected wireless link 6. The discard unit 215 discards the uplink dummy signal that has been broadcast and returned.

[0060] Next, an example of the operation of the wireless communication system 1e will be described. Figure 11 is a flowchart showing an example of the operation of the control device 21e in the fifth embodiment. Steps S601 and S602 are the same as steps S301 and S302 illustrated in Figure 5. Steps S603 to S605 are the same as steps S502 to S504 illustrated in Figure 9.

[0061] As described above, the acquisition unit 214 acquires the identification information of the user device 211. The acquisition unit 214 notifies the transmission unit 212 of the identification information of the user device 211. The transmission unit 212 broadcasts an uplink dummy signal via the control unit 213 and the selected wireless link 6. The discard unit 215 discards the uplink dummy signal that has been broadcast and returned. This makes it possible to prevent uplink dummy signal transfer loops and improve the communication quality of downlink data signals in site diversity control led by wireless communication devices.

[0062] (Sixth Embodiment) In the sixth embodiment, the main difference from the third embodiment is that the uplink dummy signal is broadcast. The sixth embodiment will be explained focusing on the differences from the third embodiment.

[0063] Figure 12 shows an example configuration of a wireless communication system 1f in the sixth embodiment. The wireless communication system 1f comprises a wireless communication device 2f, a plurality of base stations 3, a higher-level switch 4, and a higher-level device 5. The wireless communication device 2c comprises a control device 21f, a plurality of wireless units 22, a lower-level switch 23, and M user devices 211. The control device 21f comprises a transmitting unit 212, a control unit 213, an acquisition unit 214, and a discarding unit 215.

[0064] The acquisition unit 214 acquires the identification information of each user device 211. The acquisition unit 214 notifies the transmission unit 212 of the identification information of each user device 211. The transmission unit 212 broadcasts an uplink dummy signal for each piece of identification information via the control unit 213 and the selected wireless link 6. The discard unit 215 discards the uplink dummy signals that have been broadcast and returned.

[0065] Next, an example of the operation of the wireless communication system 1f will be described. Figure 13 is a flowchart showing an example of the operation of the control device 21f in the sixth embodiment. Steps S701 and S702 are the same as steps S401 and S402 illustrated in Figure 7.

[0066] If the selection of wireless link 6 is updated (step S702: YES), the control unit 213 notifies the transmission unit 212 that the selection of wireless link 6 has been updated. The transmission unit 212 broadcasts an uplink dummy signal containing the identification information of the user device 211 for each piece of identification information via the control unit 213 and the selected wireless link 6. That is, the control unit 213 broadcasts an uplink dummy signal for each piece of identification information via the selected wireless link 6 (step S703). Steps S704 and S705 are the same as steps S604 and S605 illustrated in Figure 11.

[0067] As described above, the acquisition unit 214 acquires identification information for each user device 211. The acquisition unit 214 notifies the transmission unit 212 of the identification information for each user device 211. The transmission unit 212 broadcasts an uplink dummy signal via the control unit 213 and the selected wireless link 6. The discard unit 215 discards the uplink dummy signal that has been broadcast and returned. This makes it possible to prevent uplink dummy signal transfer loops and improve the communication quality of downlink data signals in site diversity control led by wireless communication devices.

[0068] (Hardware Configuration) Figure 14 shows an example of the hardware configuration of the wireless communication device in each embodiment. The example of the hardware configuration of the wireless communication device 2 corresponds to the example of the hardware configuration of the wireless communication device in each embodiment.

[0069] The wireless communication device 2 is implemented as software by a processor 11, such as a CPU (Central Processing Unit), executing a program stored in a storage device 12 and a memory 13 that have a non-volatile recording medium (non-temporary recording medium). The program may be recorded on a computer-readable recording medium. A computer-readable recording medium is a non-temporary recording medium such as a portable medium such as a flexible disk, magneto-optical disk, ROM (Read Only Memory), CD-ROM (Compact Disc Read Only Memory), or a storage device such as a hard disk or solid-state drive (SSD) built into a computer system. The communication unit 14 performs predetermined communication processing.

[0070] The wireless communication device 2 may be implemented via hardware including an electronic circuit (or circuitry) using, for example, an LSI (Large Scale Integrated Circuit), ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), or FPGA (Field Programmable Gate Array).

[0071] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and includes designs and the like that do not depart from the spirit of this invention.

[0072] This invention is applicable to communication systems.

[0073] 1a, 1b, 1c, 1d, 1e, 1f... Wireless communication system, 2, 2a, 2b, 2c, 2d, 2e, 2f... Wireless communication device, 3... Base station, 4... Higher-level switch, 5... Higher-level device, 6... Wireless link, 10... Wireless communication system, 11... Processor, 12... Storage device, 13... Memory, 14... Communication unit, 21, 21a, 21b, 21c, 21d, 21e, 21f... Control device, 22... Wireless unit, 23... Lower-level switch, 30... Base station, 40... Higher-level switch, 50... Higher-level device, 60... Wireless link, 201... Control device, 202... User device, 203... Wireless unit, 211... User device, 212... Transmitter unit, 213... Control unit, 214... Acquisition unit, 215... Disposal unit

Claims

1. A wireless communication device comprising: a plurality of radio units connected to a plurality of base stations via radio links for each base station; a control unit that selects a radio link with higher communication quality from among the radio links for each base station; a predetermined device that selects a base station that relays the downlink data signal, and a transmitting unit that transmits an uplink dummy signal containing identification information of a user device to which a downlink data signal is to be transmitted, to at least one of the devices under the predetermined device, via the selected radio link.

2. The wireless communication device according to claim 1, wherein when the selection of a wireless link for each base station is updated, the transmitting unit transmits the uplink dummy signal to at least one of the predetermined device and the devices under the predetermined device via the selected wireless link.

3. The wireless communication device according to claim 1, further comprising an acquisition unit for acquiring the identification information for each user device, wherein the transmission unit transmits the uplink dummy signal for each piece of identification information.

4. The wireless communication device according to claim 1, further comprising a discard unit for discarding the uplink dummy signal that has been broadcast and returned.

5. The wireless communication device according to claim 1, wherein the identification information is a MAC (Media Access Control) address.

6. A wireless communication method performed by a wireless communication device, comprising the steps of: connecting to a plurality of base stations via a radio link for each base station; selecting a radio link with higher communication quality from among the radio links for each base station; and transmitting an uplink dummy signal containing identification information of a user device to which a downlink data signal is to be transmitted to at least one of a predetermined device that selects the base station that relays the downlink data signal and a device under the predetermined device, via the selected radio link.

7. A program that causes a computer to perform the following steps: a procedure for connecting to multiple base stations via a wireless link for each base station; a procedure for selecting a wireless link with higher communication quality from among the wireless links for each base station; and a procedure for transmitting an uplink dummy signal containing identification information of a user device to which a downlink data signal is to be transmitted to at least one of a predetermined device that selects a base station to relay the downlink data signal, and a device under the control of the predetermined device, via the selected wireless link.

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