Wireless communication device, wireless communication method, and program

Abstract

This wireless communication device comprises: a communication control unit that acquires distance information indicating a transmission distance between at least one of a plurality of wireless communication units which conduct wireless communication via different wireless communication schemes or the same wireless communication scheme and a wireless communication device which is the communication counterpart currently connected; and a data processing unit that, when a switching condition of the wireless communication unit is met on the basis of the acquired distance information, uses another wireless communication unit which is not connected with the wireless communication device to conduct communication, or switches a wireless communication unit used in another wireless communication 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] Wireless communication devices such as smartphones generally include wireless communication units that support multiple wireless communication standards, such as 3GPP 5G (3 Generation Partnership Project 5 Generation) (3GPP is a registered trademark), LTE (Long Term Evolution), and IEEE (Institute of Electrical and Electronics Engineers) 802.11.

[0003] A wireless communication device generally determines which wireless communication method to use for wireless communication using a wireless communication unit corresponding to the wireless communication method based on connection information or quality information of the wireless communication unit, or determines the wireless communication method to use for communication based on a control instruction from the opposing wireless communication device to which the wireless communication unit is connected. Each wireless communication method has its own characteristics. For example, IEEE802.11ad uses a higher frequency band than conventional methods, which can be expected to achieve a larger capacity, but has the disadvantage of being difficult to use for long-distance transmission due to large free space loss (see, for example, Non-Patent Document 1).

[0004] The quality of wireless communication varies from moment to moment due to environmental changes such as the movement of wireless communication devices and surrounding obstructions and reflecting objects. Therefore, even if a wireless communication method that is expected to provide optimal wireless communication quality at a certain time is selected, that wireless communication method may no longer be optimal as time changes. Furthermore, depending on the speed of the fluctuations, there is a possibility that significant degradation of wireless communication quality may occur, such as temporary communication interruptions. Therefore, it has been difficult to select an optimal wireless communication method in a fluctuating propagation path environment.

[0005] Among the wireless communication methods used by wireless communication devices, for example, wireless communication methods using relatively higher frequency bands than conventional methods, such as millimeter wave bands represented by 5G NR (5G New Radio) and IEEE 802.11ad, can be expected to have a larger communication channel capacity than those using lower frequency bands due to the wide frequency bands used. For this reason, while it is preferable to actively use wireless communication methods such as 5G NR and IEEE 802.11ad in areas where high frequency bands are available, the area where high frequency bands are available is generally narrower than that of lower frequency bands due to the large amount of distance attenuation. Therefore, when it is expected that the device will leave the area where high frequency bands are available, it is necessary to quickly switch communication to a wireless communication method using a lower frequency band to avoid communication interruptions.

[0006] International Publication No. 2020 / 028983

[0007] Takinami et al., "Standardization Trends and Elemental Technologies of Millimeter-Wave Wireless LAN Systems," IEICE Communications Society Magazine, Fall 2016, No. 38, pp. 100-106.

[0008] On the other hand, it is difficult to estimate the area edge based on quality information such as the received signal strength indicator (RSSI) and reference signal received power (RSRP) of the signal used for communication. This is because, as shown in Fig. 4, received power values ​​such as the received signal strength and reference signal received power may vary in a manner that is not unique to each location. As such, it has been difficult to select a wireless communication method using quality information.

[0009] In view of the above circumstances, an object of the present invention is to provide a technique that can avoid communication interruptions by using information other than quality information.

[0010] One aspect of the present invention is a wireless communication device that includes a communication control unit that acquires distance information indicating the transmission distance between at least one of multiple wireless communication units that perform wireless communication using different or the same wireless communication method and a wireless communication device that is the currently connected communication partner, and a data processing unit that, when a switching condition for the wireless communication unit is met based on the acquired distance information, performs communication using another wireless communication unit that is not connected to the wireless communication device, or switches the wireless communication unit used in the other wireless communication device.

[0011] One aspect of the present invention is a wireless communication method that acquires distance information indicating the transmission distance between at least one of multiple wireless communication units that perform wireless communication using different or the same wireless communication method and a wireless communication device that is the currently connected communication partner, and when a switching condition for the wireless communication unit is met based on the acquired distance information, communicates using another wireless communication unit that is not connected to the wireless communication device, or switches the wireless communication unit used in the other wireless communication device.

[0012] One aspect of the present invention is a program for causing a computer to execute the following steps: an acquisition step of acquiring distance information indicating the transmission distance between at least one of multiple wireless communication units that perform wireless communication using different or the same wireless communication method and a wireless communication device that is the currently connected communication partner; and a communication step of performing communication using another wireless communication unit that is not connected to the wireless communication device, or switching the wireless communication unit used in the other wireless communication device, when a switching condition for the wireless communication unit is met based on the distance information acquired in the acquisition step.

[0013] According to the present invention, it becomes possible to avoid communication interruptions by using information other than quality information.

[0014] It is a diagram showing a configuration example of a wireless communication device in a first embodiment. It is a flowchart showing a processing flow of the wireless communication device in the first embodiment. It is a diagram showing a configuration example of a wireless communication device in a third embodiment. It is a diagram for explaining a problem of the related art.

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] (First embodiment) Fig. 1 is a diagram showing an example of the configuration of a wireless communication device 10 in a first embodiment. The wireless communication device 10 includes multiple wireless communication units and performs wireless communication with other wireless communication devices. As an example, the wireless communication device 10 is a terminal station device, and the other wireless communication devices are base station devices. The wireless communication device 10 and the other wireless communication devices are included in a wireless communication system. The other wireless communication devices include one or more wireless communication units and perform wireless communication with the wireless communication device 10.

[0017] The wireless communication device 10 may be a base station device, and the other wireless communication device may be a terminal station device. When the wireless communication device 10 is a base station device, the base station device has the same configuration as the wireless communication device 10.

[0018] The wireless communication device 10 includes a data processing unit 11, a wireless communication unit 12, a communication control unit 13, a round-trip time measurement signal transmitting unit 14, a round-trip time measuring unit 15, a wireless communication unit 16, an antenna 17, and an antenna 18.

[0019] The data processing unit 11 inputs and outputs data to and from a host device or another base station device that is located above the wireless communication device 10. For example, the data processing unit 11 transmits a signal received from another wireless communication device to the host device or another base station device. For example, the data processing unit 11 receives a signal addressed to another wireless communication device from the host device or another base station.

[0020] Furthermore, when a wireless communication unit switching condition is satisfied, the data processing unit 11 performs communication using another wireless communication unit that is not connected to another wireless communication device. Here, the wireless communication unit switching condition refers to a condition for switching the wireless communication unit used for communication, such as the transmission distance between the wireless communication device 10 and the other wireless communication device with which the communication is being performed being outside a predetermined range. The predetermined range is the range in which communication can be performed using the wireless communication method of the wireless communication unit used for communication. In other words, the wireless communication unit switching condition is satisfied when the range in which communication can be performed using the wireless communication method of the wireless communication unit used for communication is exceeded. In this way, the wireless communication device 10 avoids communication interruptions by appropriately detecting the edge of the area in which communication can be performed using the wireless communication method of the wireless communication unit used for communication based on the transmission distance.

[0021] The wireless communication unit 12 communicates with other wireless communication devices. The wireless communication unit 12 communicates with other wireless communication devices, for example, by a wireless communication method using a high frequency band. Examples of wireless communication methods using a high frequency band include 5G NR (FR2 (Frequency Range 2)) and IEEE802.11ad. Note that the wireless communication method used by the wireless communication unit 12 is not limited to these.

[0022] The wireless communication unit 12 transmits the round trip time measurement signal output from the round trip time measurement signal transmitter 14 to the other wireless communication device via the antenna 17. The round trip time measurement signal is a signal used to estimate the transmission distance between the wireless communication device 10 and the other wireless communication device with which it is currently connected.

[0023] When the wireless communication unit 12 receives a response to the round-trip time measurement signal from another connected wireless communication device, the wireless communication unit 12 outputs the response to the received round-trip time measurement signal to the round-trip time measurement unit 15 .

[0024] The wireless communication unit 12 may form directional beams in different directions by controlling the amplitude or phase of the antenna 17 in accordance with instructions from the communication control unit 13. When configured in this manner, the number of directional beams formed by the wireless communication device 10 is not particularly limited. A directional beam is a beam that has directivity in a specific direction. The wireless communication unit 12 switches the directional beams and transmits signals in accordance with instructions from the communication control unit 13. The wireless communication unit 12 receives signals (e.g., responses) transmitted from other wireless communication devices via the antenna 17.

[0025] The communication control unit 13 controls the operation of the wireless communication unit 12 and the round-trip time measurement signal transmission unit 14. For example, when the wireless communication unit 12 is connected to another wireless communication device, the communication control unit 13 instructs the round-trip time measurement signal transmission unit 14 to transmit a round-trip time measurement signal. Furthermore, the communication control unit 13 estimates the transmission distance between the wireless communication unit 12 and the other connected wireless communication device based on the round-trip time (RTT) measured by the round-trip time measurement unit 15. For example, the communication control unit 13 estimates the transmission distance using the round-trip time and the speed of light. In this way, the communication control unit 13 acquires distance information indicating the transmission distance. The communication control unit 13 determines whether a switching condition for the wireless communication unit is satisfied based on the estimated transmission distance.

[0026] In addition, the communication control unit 13 may previously store a table that correlates the relationship between the round-trip time of a signal and the estimated transmission distance, and obtain distance information indicating the transmission distance based on the round-trip time measured by the round-trip time measurement unit 15.

[0027] The round-trip time measurement signal transmitter 14 generates a round-trip time measurement signal in response to an instruction from the communication control unit 13, and outputs the generated round-trip time measurement signal to the wireless communication unit 12. The round-trip time measurement signal transmitter 14 instructs the round-trip time measurement unit 15 to measure the round-trip time at the timing when the round-trip time measurement signal is output.

[0028] In response to an instruction from the round-trip time measurement signal transmitter 14, the round-trip time measurement unit 15 measures the round-trip time from the time the round-trip time measurement signal is transmitted to the time the response to the round-trip time measurement signal is received. For example, the round-trip time measurement unit 15 acquires the timing at which the round-trip time measurement signal transmitter 14 instructs it to measure the round-trip time as the time the round-trip time measurement signal is transmitted. The round-trip time measurement unit 15 acquires the timing at which the response to the round-trip time measurement signal is received via the wireless communication unit 12 as the time the response to the round-trip time measurement signal is received. The round-trip time measurement unit 15 measures the round-trip time based on the time of transmission and the time of reception. For example, the round-trip time measurement unit 15 measures the difference between the time of transmission and the time of reception as the round-trip time.

[0029] The transmission time of the round-trip time measurement signal and the reception time of the response to the round-trip time measurement signal are not limited to the above. The transmission time of the round-trip time measurement signal may be, for example, the time when the round-trip time measurement signal is transmitted by the wireless communication unit 12. The reception time of the response to the round-trip time measurement signal may be, for example, the time when the response to the round-trip time measurement signal is received by the wireless communication unit 12. In this case, the wireless communication unit 12 outputs information indicating the transmission time and information indicating the reception time to the round-trip time measurement unit 15. The round-trip time measurement unit 15 measures the round-trip time based on the information indicating the transmission time and the information indicating the reception time output from the wireless communication unit 12.

[0030] The wireless communication unit 16 is a communication unit that is used when a switching condition for the wireless communication unit is satisfied. The wireless communication unit 16 communicates with other wireless communication devices. For example, the wireless communication unit 16 communicates with other wireless communication devices using a wireless communication method that uses a frequency band (e.g., a low frequency band) different from that of the wireless communication unit 12. Examples of wireless communication methods that use a low frequency band include IEEE 802.11ac, IEEE 802.11ax, and 5G NR (FR1). Note that the wireless communication method used by the wireless communication unit 16 is not limited to these.

[0031] The antenna 17 is provided in association with the wireless communication unit 12. The antenna 17 emits the electrical signal output from the wireless communication unit 12 as radio waves. The antenna 17 receives radio waves transmitted from other wireless communication devices. The antenna 17 may form directional beams in different directions.

[0032] The antenna 18 is provided in association with the wireless communication unit 16. The antenna 18 emits the electrical signal output from the wireless communication unit 16 as radio waves. The antenna 18 receives radio waves transmitted from other wireless communication devices. The antenna 18 may form directional beams in different directions.

[0033] 2 is a flowchart showing the flow of processing of the wireless communication device 10 in the first embodiment. The communication control unit 13 of the wireless communication device 10 determines whether the wireless communication unit 12 is currently connected to another wireless communication device (step S101). If the communication control unit 13 determines that the wireless communication unit 12 is not currently connected to another wireless communication device (step S101-NO), the communication control unit 13 repeatedly executes the processing of step S101.

[0034] On the other hand, if the communication control unit 13 determines that the wireless communication unit 12 is connected to another wireless communication device (step S101—YES), the communication control unit 13 instructs the round trip time measurement signal transmitter 14 to transmit a round trip time measurement signal (step S102). The round trip time measurement signal transmitter 14 generates a round trip time measurement signal in response to the instruction from the communication control unit 13. The round trip time measurement signal transmitter 14 outputs the generated round trip time measurement signal to the wireless communication unit 12. The round trip time measurement signal transmitter 14 instructs the round trip time measurement unit 15 to measure the round trip time at the timing of outputting the round trip time measurement signal to the wireless communication unit 12. The round trip time measurement unit 15 acquires the timing of the instruction to measure the round trip time from the round trip time measurement signal transmitter 14 as the transmission time of the round trip time measurement signal.

[0035] The wireless communication unit 12 transmits the round-trip time measurement signal output from the round-trip time measurement signal transmitter 14 to the other wireless communication device via the antenna 17 (step S103). The wireless communication device 10 waits for a predetermined time (step S104). The communication control unit 13 determines whether a response to the round-trip time measurement signal has been received during or after the predetermined time has elapsed (step S105).

[0036] If the communication control unit 13 determines that it has not received a response to the round-trip time measurement signal (step S105—NO), the communication control unit 13 executes the process of step S103 again. In this case, the round-trip time measurement unit 15 acquires the timing at which it is instructed by the round-trip time measurement signal transmitter 14 to newly measure the round-trip time as the transmission time of the round-trip time measurement signal.

[0037] If the communication control unit 13 determines that a response to the round-trip time measurement signal has been received (step S105—YES), the wireless communication unit 12 outputs the received response to the round-trip time measurement unit 15. The round-trip time measurement unit 15 acquires the timing at which the response to the round-trip time measurement signal is received via the wireless communication unit 12 as the reception time of the response to the round-trip time measurement signal. The round-trip time measurement unit 15 measures the round-trip time based on the transmission time and the reception time. The round-trip time measurement unit 15 outputs information indicating the measured round-trip time to the communication control unit 13.

[0038] The communication control unit 13 estimates the transmission distance between the wireless communication device 10 and the other wireless communication device based on the information indicating the round-trip time output from the round-trip time measurement unit 15 and the speed of light (step S106). The communication control unit 13 determines whether the switching condition for the wireless communication unit is satisfied based on the estimated transmission distance (step S107). The communication control unit 13 determines that the switching condition is not satisfied if the transmission distance is within a predetermined range. The communication control unit 13 determines that the switching condition is satisfied if the transmission distance is not within the predetermined range (outside the predetermined range).

[0039] If the communication control unit 13 determines that the switching condition for the wireless communication unit is not satisfied (step S107-NO), it determines that the wireless communication device 10 is located in an appropriate area for the wireless communication method of the wireless communication unit 12. In this case, the wireless communication device 10 executes the process of step S101.

[0040] On the other hand, if the communication control unit 13 determines that the switching condition for the wireless communication unit is satisfied (step S107—YES), the communication control unit 13 instructs the data processing unit 11 to communicate using another wireless communication unit. For example, the communication control unit 13 instructs the data processing unit 11 to communicate using a wireless communication unit (e.g., wireless communication unit 16) that uses a different frequency band from that of the wireless communication unit 12. The data processing unit 11 switches the wireless communication unit used for communication from the wireless communication unit 12 to the wireless communication unit 16 in accordance with the instruction from the communication control unit 13 (step S108). Therefore, the data processing unit 11 outputs the data to be transmitted to the wireless communication unit 16.

[0041] This allows the wireless communication device 10 to communicate using a wireless communication unit of a different frequency (e.g., wireless communication unit 16) in advance in a situation where the wireless communication device 10 has reached the edge of the area of ​​the wireless communication method and there is a high possibility that the communication quality will deteriorate, thereby avoiding communication interruptions due to deterioration in communication quality.

[0042] The wireless communication device 10 configured as described above includes a communication control unit 13 that acquires distance information indicating the transmission distance between at least one of the multiple wireless communication units 12, 16 that perform wireless communication using different wireless communication methods and the wireless communication device that is the currently connected communication partner, and a data processing unit 11 that performs communication using another wireless communication unit (e.g., wireless communication unit 16) that is not connected to another wireless communication device when a switching condition for the wireless communication unit is met based on the acquired distance information.

[0043] In this way, based on the transmission distance between the wireless communication device 10 and another wireless communication device, the wireless communication device 10 can switch in advance to a wireless communication unit 16 that uses a wireless communication method different from that of the wireless communication unit 12 before the wireless communication device 10 reaches the edge of the area of ​​the wireless communication unit 12 that the wireless communication device 10 is using and communication quality deteriorates. Therefore, it is possible to avoid communication interruptions due to deterioration of communication quality by using information other than quality information. As a result, stable wireless communication can be provided.

[0044] In particular, when using high-frequency bands, frequency resources in those bands are more plentiful than in low-frequency bands. In other words, wireless communication devices using high-frequency bands are often assigned relatively wide radio frequency bandwidths. Because the signal bandwidth and the symbol rate are proportional to each other, the symbol rate increases when wideband signals are used. This shortens the symbol interval in the time domain, which is expected to improve the accuracy of measuring the round-trip time of communication signals. Therefore, transmission distance can be easily estimated without combining and processing signals transmitted from multiple, distributed transmitters, as in the conventional GPS (Global Positioning System).

[0045] Second Embodiment In a wireless communication system using a high frequency band, signals may be transmitted by performing beamforming, which narrows the energy of radio waves in a specific directional direction. Furthermore, when communication uses a reflected path, the communication may temporarily go through a reflected path, causing the estimated transmission distance value within the area to fluctuate significantly. Particularly when communication is performed via a reflected path, the transmission distance value obtained may be significantly different from the direct transmission distance between wireless communication devices. In such a case, if a wireless communication system switching decision is made using the instantaneous estimated transmission distance, as in the first embodiment, it is possible that the wireless communication device may switch to a different wireless communication system even though it is still located within the area of ​​that wireless communication system. As a result, the high frequency band may become unavailable, resulting in degradation of transmission characteristics.

[0046] Therefore, in the second embodiment, an embodiment for avoiding such problems will be described. Specifically, the wireless communication device in the second embodiment estimates the transmission distance multiple times at different timings, and estimates the transmission distance used to determine the switching condition of the wireless communication unit based on the multiple estimated transmission distances. That is, the wireless communication device in the second embodiment acquires distance information indicating the transmission distance based on the results of multiple measurements at different timings. The configuration of the wireless communication device in the second embodiment is the same as that of the first embodiment. The following description will focus on the differences from the first embodiment.

[0047] The communication control unit 13 performs the same processing as the communication control unit 13 in the first embodiment. Furthermore, the communication control unit 13 estimates the transmission distance between the own device and the other wireless communication device with which it is connected, based on the round-trip time measured by the round-trip time measurement unit 15. The communication control unit 13 executes the processing of estimating the transmission distance multiple times at different timings. Then, the communication control unit 13 estimates the final transmission distance using the multiple transmission distance values. The following two methods can be given as methods for estimating the final transmission distance.

[0048] (First Method) The first method is a method using only averaging processing. The communication control unit 13 stores a plurality of estimated transmission distance values ​​in advance, and obtains the average value of the stored plurality of transmission distance values ​​as the final transmission distance. The communication control unit 13 calculates N (N is an integer of 2 or more) transmission distances L ｎ The average value −L (− is a superscript of L) of the above is calculated based on the following formula (1).

[0049]

[0050] The communication control unit 13 determines whether the switching condition for the wireless communication unit is satisfied based on the calculated average value −L. If the calculated average value −L is within a predetermined range, the communication control unit 13 determines that the switching condition is not satisfied. If the average value −L is not within the predetermined range (outside the predetermined range), the communication control unit 13 determines that the switching condition is satisfied.

[0051] (Second Method) The second method is a method in which outliers are removed before performing averaging. If only averaging is performed as in the first method, there is a possibility that the averaging may be affected by a small number of transmission distance values ​​used for averaging, or by the presence of a relatively large transmission distance value. As a result, there is a risk of erroneously determining the switching condition of the wireless communication unit. Therefore, the communication control unit 13 removes such relatively large transmission distance values ​​as outliers before performing averaging.

[0052] A set of N transmission distance values ​​L is denoted by {L ｎ}. The communication control unit 13 sets the set {L ｎ}, the communication control unit 13 extracts K transmission distance values ​​L within a predetermined range of the calculated median value M from the N transmission distance values. The extracted set is called {L ´ ｋ}. The communication control unit 13 ´ ｋ}, the communication control unit 13 performs an averaging process based on the following equation (2): As a result, the communication control unit 13 calculates the average value −L′ (− is a superscript of L′).

[0053]

[0054] The communication control unit 13 determines whether the switching condition for the wireless communication unit is satisfied based on the calculated average value -L'. If the calculated average value -L' is within a predetermined range, the communication control unit 13 determines that the switching condition is not satisfied. If the average value -L' is not within the predetermined range (outside the predetermined range), the communication control unit 13 determines that the switching condition is satisfied.

[0055] In the second method, the communication control unit 13 may calculate the average value −L′ by only removing outliers.

[0056] Whether to use the first method or the second method may be preset in the wireless communication device 10. Furthermore, the wireless communication device 10 may switch between the first method and the second method depending on the time of day.

[0057] (Processing of Wireless Communication Device 10) Next, the flow of processing of the wireless communication device 10 in the second embodiment will be described. Here, the processing in the first embodiment will be described as an example. When the communication control unit 13 determines in the processing of step S101 that the wireless communication unit 12 is connected to another wireless communication device (step S101-YES), the wireless communication device 10 executes the processing from step S102 to step S106 a predetermined number of times. This allows the communication control unit 13 to acquire the transmission distance value a predetermined number of times.

[0058] For example, the communication control unit 13 estimates the transmission distance and then stores the estimated transmission distance value in a storage unit (not shown). The communication control unit 13 determines whether the transmission distance value stored in the storage unit is equal to or greater than a predetermined number. If the transmission distance value stored in the storage unit is less than the predetermined number, the communication control unit 13 instructs the round-trip time measurement signal transmitter 14 to transmit a round-trip time measurement signal. On the other hand, if the transmission distance value stored in the storage unit is equal to or greater than the predetermined number, the communication control unit 13 uses the multiple transmission distance values ​​stored in the storage unit to estimate the final transmission distance based on the first method or the second method.

[0059] The communication control unit 13 determines whether the switching condition for the wireless communication unit is satisfied based on the estimated final transmission distance. The communication control unit 13 determines that the switching condition is not satisfied if the final transmission distance is within a predetermined range. The communication control unit 13 determines that the switching condition is satisfied if the final transmission distance is not within the predetermined range (outside the predetermined range).

[0060] If the communication control unit 13 determines that the switching condition for the wireless communication unit is not satisfied, it determines that the wireless communication device 10 is located in an appropriate area for the wireless communication method of the wireless communication unit 12. In this case, the wireless communication device 10 executes the process of step S101.

[0061] On the other hand, when the communication control unit 13 determines that the switching condition for the wireless communication unit is satisfied, the communication control unit 13 instructs the data processing unit 11 to communicate using another wireless communication unit. For example, the communication control unit 13 instructs the data processing unit 11 to communicate using a wireless communication unit (e.g., wireless communication unit 16) that uses a frequency band different from that of the wireless communication unit 12. The data processing unit 11 switches the wireless communication unit used for communication from the wireless communication unit 12 to the wireless communication unit 16 in accordance with the instruction from the communication control unit 13. Therefore, the data processing unit 11 outputs the data to be transmitted to the wireless communication unit 16.

[0062] According to the wireless communication device 10 of the second embodiment configured as above, it is possible to obtain the same effects as those of the first embodiment.

[0063] Furthermore, in the wireless communication device 10 according to the second embodiment, whether or not the switching condition for the wireless communication unit is satisfied is determined based on an average value of multiple transmission distances obtained at different times, rather than a single transmission distance value, which reduces the risk of erroneous determination of whether or not the switching condition for the wireless communication unit is satisfied, compared to the first embodiment.

[0064] (Third embodiment) There is a method for stabilizing communication by providing a wireless communication device with multiple wireless communication units that use the same wireless communication method and controlling each unit to connect to a different opposing wireless communication device (see, for example, Patent Document 1). The present invention can also be applied to this method.

[0065] Therefore, in the third embodiment, a configuration will be described in which, for each of multiple wireless communication units that use the same wireless communication method, the transmission distance is estimated using the method shown in the first or second embodiment, and a decision to switch the wireless communication unit is made based on the estimated transmission distance.

[0066] 3 is a diagram showing an example of the configuration of a wireless communication device 10a according to the third embodiment. The wireless communication device 10a includes multiple wireless communication units and performs wireless communication with other wireless communication devices. As an example, the wireless communication device 10a is a terminal station device, and the other wireless communication devices are base station devices. The wireless communication device 10a and the other wireless communication devices are included in a wireless communication system. The other wireless communication devices include one or more wireless communication units and perform wireless communication with the wireless communication device 10a.

[0067] The wireless communication device 10a may be a base station device, and the other wireless communication device may be a terminal station device. When the wireless communication device 10a is a base station device, the base station device has the same configuration as the wireless communication device 10a.

[0068] The wireless communication device 10a includes a data processing unit 11, a plurality of wireless communication units 12-1 and 12-2, a communication control unit 13a, a round-trip time measurement signal transmitting unit 14a, a round-trip time measuring unit 15a, a wireless communication unit 16, a plurality of antennas 17-1 and 17-2, and an antenna 18.

[0069] 3 shows a configuration in which the wireless communication device 10a includes two wireless communication units 12 and two antennas 17, the wireless communication device 10a may be configured to include three or more wireless communication units 12 and three or more antennas 17. In the following description, the multiple wireless communication units 12-1 and 12-2 will be referred to as wireless communication units 12 when there is no particular need to distinguish them, and the multiple antennas 17-1 and 17-2 will be referred to as antennas 17 when there is no particular need to distinguish them.

[0070] Each wireless communication unit 12 communicates with a different wireless communication device. For example, each wireless communication unit 12 communicates with a different wireless communication device by a wireless communication method using a high frequency band. Note that the wireless communication method used by each wireless communication unit 12 is the same. Note that although the wireless communication device 10a includes multiple wireless communication units 12, the wireless communication device 10a only has one wireless communication unit 12 for transmitting a signal received from the data processing unit 11 at a given time, or passing a received signal to the data processing unit 11, regardless of whether the frequency is the same or different.

[0071] Each wireless communication unit 12 transmits the round trip time measurement signal output from the round trip time measurement signal transmitter 14a to another wireless communication device via the antenna 17. For example, wireless communication unit 12-1 transmits the round trip time measurement signal output from the round trip time measurement signal transmitter 14a to a first wireless communication device via the antenna 17-1. For example, wireless communication unit 12-2 transmits the round trip time measurement signal output from the round trip time measurement signal transmitter 14a to a second wireless communication device via the antenna 17-2.

[0072] When each wireless communication unit 12 receives a response to the round-trip time measurement signal from another wireless communication device with which it is connected, it outputs the response to the received round-trip time measurement signal to the round-trip time measurement unit 15a.

[0073] Each wireless communication unit 12 may form directional beams in different directions by controlling the amplitude or phase of the antenna 17 in accordance with instructions from the communication control unit 13a. In this configuration, there is no particular limit to the number of directional beams formed by the wireless communication device 10a. A directional beam is a beam that has directivity in a specific direction. Each wireless communication unit 12 switches the directional beam and transmits a signal in accordance with instructions from the communication control unit 13a. Each wireless communication unit 12 receives a signal (e.g., a response) transmitted from another wireless communication device via the antenna 17.

[0074] The communication control unit 13a controls the operation of the wireless communication units 12-1 and 12-2 and the round-trip time measurement signal transmitter 14a. For example, when the wireless communication units 12-1 and 12-2 are connected to different wireless communication devices, the communication control unit 13a instructs the round-trip time measurement signal transmitter 14a to transmit a round-trip time measurement signal. Furthermore, the communication control unit 13a estimates the transmission distance between the wireless communication device 10a and each connected wireless communication device based on the round-trip time measured by the round-trip time measurement unit 15a. For example, the communication control unit 13a estimates the transmission distance between the wireless communication device 10a and another wireless communication device connected via the wireless communication unit 12-1. For example, the communication control unit 13a estimates the transmission distance between the wireless communication device 10a and another wireless communication device connected via the wireless communication unit 12-2.

[0075] The communication control unit 13a estimates the transmission distance using a method similar to that described in the first or second embodiment. The communication control unit 13a determines whether the switching condition for the wireless communication unit is satisfied based on the transmission distance estimated between the wireless communication unit 13a and another wireless communication device connected via each wireless communication unit 12. For example, if any or all of the transmission distances obtained by each wireless communication unit 12 are within a predetermined range, the communication control unit 13a determines that the switching condition for the wireless communication unit is not satisfied. Note that the value of the predetermined range may be different for each wireless communication unit 12. For example, if all of the transmission distances obtained by each wireless communication unit 12 are not within the predetermined range, the communication control unit 13a determines that the switching condition for the wireless communication unit is satisfied.

[0076] Using a wireless communication unit of a different frequency (e.g., wireless communication unit 16) only when all of the transmission distances obtained by each wireless communication unit 12 are not within a specified range means controlling the use of wireless in a high frequency band that can be expected to have as large a capacity as possible.

[0077] The communication control unit 13a may determine that the condition for switching wireless communication units is satisfied when any of the transmission distances obtained by the wireless communication units 12 is not within a predetermined range. In this case, the communication control unit 13a instructs the data processing unit 11 to switch the wireless communication unit 12 whose transmission distance is not within the predetermined range to the wireless communication unit 16 and perform communication.

[0078] In this way, when the transmission distance of one of the multiple wireless communication units 12 is not within a specified range, using a wireless communication unit of a different frequency (e.g., wireless communication unit 16) means controlling the communication so as to avoid as much as possible the risk of communication interruption due to deterioration in transmission quality.

[0079] The round-trip time measurement signal transmitter 14a generates a round-trip time measurement signal in response to an instruction from the communication control unit 13a and outputs the generated round-trip time measurement signal to each wireless communication unit 12. Here, the round-trip time measurement signal transmitter 14a may output the generated round-trip time measurement signal to each wireless communication unit 12 at different timings so that each wireless communication unit 12 can transmit the round-trip time measurement signal and receive a response to the round-trip time measurement signal at different timings. For example, the round-trip time measurement signal transmitter 14a may output the round-trip time measurement signal to wireless communication unit 12-1, and after wireless communication unit 12-1 receives the response, output the round-trip time measurement signal to wireless communication unit 12-2. The round-trip time measurement signal transmitter 14a instructs the round-trip time measurement unit 15a to measure the round-trip time at the timing when it outputs the round-trip time measurement signal to the wireless communication unit 12.

[0080] In response to an instruction from the round-trip time measurement signal transmitter 14a, the round-trip time measurement unit 15a measures the round-trip time from the time the round-trip time measurement signal is transmitted to the time the response to the round-trip time measurement signal is received. For example, the round-trip time measurement unit 15a acquires the timing at which the round-trip time measurement signal transmitter 14a instructs it to measure the round-trip time as the time the round-trip time measurement signal is transmitted. The round-trip time measurement unit 15a acquires the timing at which the response to the round-trip time measurement signal is received via the wireless communication unit 12 as the time the response to the round-trip time measurement signal is received. The round-trip time measurement unit 15a measures the round-trip time based on the time of transmission and the time of reception. For example, the round-trip time measurement unit 15a measures the difference between the time of transmission and the time of reception as the round-trip time.

[0081] In this embodiment, a plurality of wireless communication units 12 are provided. Therefore, the round-trip time measurement unit 15a needs to distinguish between the wireless communication units 12 and measure the round-trip time for each wireless communication unit 12. The round-trip time measurement unit 15a assigns identification information for identifying the wireless communication unit 12 to information indicating the measured round-trip time, and outputs the information to the communication control unit 13a. This allows the communication control unit 13a to estimate the transmission distance for each wireless communication unit 12.

[0082] According to the wireless communication device 10a configured as above, it is possible to obtain the same effects as those of the first embodiment.

[0083] Furthermore, the wireless communication device 10a can determine whether to switch between wireless communication units even in a configuration that includes a plurality of wireless communication units 12. This improves convenience.

[0084] (Modification) In the above-described embodiment, when all of the wireless communication units 12 included in the wireless communication device 10a are connected to other wireless communication devices, the configuration is shown in which the transmission distance is estimated for each wireless communication unit 12 based on the round-trip time obtained via each wireless communication unit 12. In contrast, when some of the wireless communication units 12 in the wireless communication device 10a are connected to other wireless communication devices, the transmission distance may be estimated based on the round-trip time obtained via some of the wireless communication units 12 connected to the other wireless communication devices. In this case, the wireless communication device 10a determines whether the switching condition is satisfied in some of the wireless communication units 12 connected to the other wireless communication devices.

[0085] (Variation 1 common to the first to third embodiments) In wireless communication systems using high frequency bands, signals may be transmitted using beamforming, which focuses the energy of radio waves in a specific directional direction to compensate for the increased attenuation over distance. In such cases, it is expected that a multipath environment in which signals arrive with time differences from multiple reflection paths is unlikely to occur. For this reason, the present invention can also be applied to wireless communication devices 10, 10a that use beamforming. In such cases, the direction of the opposing wireless communication device 10, 10a can be estimated from the direction of the directional beam. Therefore, the position of the opposing wireless communication device 10, 10a can be estimated from this and the round-trip time, and the wireless communication method may be switched based on this.

[0086] (Variation 2 common to the first to third embodiments) In the above-described embodiments, the wireless communication unit 12 and the wireless communication unit 16 are described as examples of different wireless communication methods using different frequency bands, but if the wireless communication method used by the wireless communication unit 12 and the wireless communication method used by the wireless communication unit 16 cover different areas, the frequency bands do not necessarily need to be different. In other words, if the wireless communication method used by the wireless communication unit 12 and the wireless communication method used by the wireless communication unit 16 are the same, and the wireless communication method of the wireless communication unit 12 covers a wide area because it uses a high-output antenna 17, and the wireless communication method of the wireless communication unit 16 covers a narrow area because it uses a low-output antenna 18, the present invention can be applied to such a case, although it is not a case of switching the wireless communication method between different frequency bands.

[0087] (Modification 3 common to the first to third embodiments) In some cases, wireless communication standards differ for each wireless frequency, such as IEEE 802.11ac (5 GHz band) and IEEE 802.11ad (60 GHz band) in a wireless LAN (Local Area Network), and in such cases, the wireless communication method may differ for each wireless communication unit that switches between them. On the other hand, there are also wireless communication methods that allow the same communication method to use different wireless frequency bands. For example, 3GPP 5G specifies a wide range of frequency bands, from several hundred MHz to several tens of GHz, and the present invention can be similarly applied to cases where such bands are used.

[0088] (Variation 4 common to the first to third embodiments) In each of the above-described embodiments, a configuration has been shown in which switching between multiple wireless communication units (wireless communication unit 12 and wireless communication unit 16) is performed within the wireless communication device 10, 10a. Alternatively, a dedicated aggregation device may determine whether the switching between the multiple wireless communication units (whether the switching conditions for the wireless communication units are met) may be performed. In this configuration, the wireless communication device 10, 10a transmits information about the estimated transmission distance to the aggregation device via wired communication or wireless communication. The aggregation device determines whether the switching conditions for the wireless communication units are met based on the transmission distance information transmitted from the wireless communication device 10, 10a. If the switching conditions for the wireless communication units are met, the aggregation device instructs the wireless communication device 10, 10a to switch the wireless communication unit. The wireless communication device 10, 10a switches the wireless communication unit to be used for communication in accordance with the instruction transmitted from the aggregation device.

[0089] (Variation 5 Common to the First to Third Embodiments) In the above-described embodiments, either a terminal device, which is generally equipped on a person, machine, or the like and is often mobile, or a base station device, which is generally relatively inactive on the ground or the like and has a communication path to an external network such as the Internet, has been collectively described as a wireless communication device without much distinction. This is because the present invention is applicable to either of them, and of course, the present invention may also be applied to either of them. For example, the terminal station device may estimate the transmission distance and autonomously switch the wireless communication unit. For example, the terminal station device may estimate the transmission distance, and the data processing unit 11 may transmit information about the estimated transmission distance to the base station device via the wireless communication unit 12, and the base station device or its upper aggregation device may switch the wireless communication unit. This means that the data processing unit 11 switches the wireless communication unit used in another wireless communication device. Alternatively, the base station device may estimate the transmission distance between the terminal station device and the base station device, and the base station device or its upper aggregation device may determine whether a switching condition for the wireless communication unit is satisfied based on the estimated transmission distance, and switch the wireless communication method between the base station device and the terminal station device.

[0090] (Variation 6 common to the first to third embodiments) In each of the above-described embodiments, the wireless communication device 10, 10a is configured to measure the round-trip time by transmitting the round-trip time measurement signal generated by the round-trip time measurement signal transmitter 14, 14a to the other wireless communication device with which it is connected and receiving a response to the round-trip time measurement signal. In contrast, the wireless communication device 10, 10a may be configured to measure the round-trip time between the other wireless communication device with which it is connected and by using another signal without using the round-trip time measurement signal. The other signal may be any signal that is exchanged with the other wireless communication device with which it is connected, such as a signal for exchanging information related to communication with the other wireless communication device with which it is connected, such as control information.

[0091] Examples of control information include the exchange of signals performed by a procedure called SLS (Sector Level Sweep) in IEEE 802.11ad, which is a signal used when determining a directional beam during transmission and reception, and signals exchanged in a series of procedures in 5G NR, in which multiple signal blocks called SS / PBCH (Synchronization Signal / Physical Broadcast CHannel) are transmitted sequentially in a time-division manner from a base station device for each directional beam, and the opposing wireless communication device reads these, measures which beam has the highest received power, and feeds back the measurement results to the base station device.

[0092] When configured in this manner, the wireless communication device 10, 10a does not need to include the round-trip time measurement signal transmitter 14, 14a. In this case, the communication control unit 13, 13a may instruct the round-trip time measurement unit 15, 15a to measure the round-trip time at the timing when it instructs the wireless communication unit 12 to transmit control information. In response to the instruction from the communication control unit 13, 13a, the round-trip time measurement unit 15, 15a measures the round-trip time from the time when another signal is transmitted to the time when a response to that signal is received.

[0093] Some or all of the functional units of the wireless communication device 10, 10a in the above-described embodiments are realized as software by one or more processors, such as a CPU (Central Processing Unit), executing a program stored in a storage device having a non-volatile storage medium (non-transitory storage medium) and memory. The program may be recorded on a computer-readable non-transitory storage medium. Examples of computer-readable non-transitory storage media include portable media such as a flexible disk, a magneto-optical disk, a ROM (Read Only Memory), and a CD-ROM (Compact Disc-ROM), and storage devices such as a hard disk built into a computer system.

[0094] Some or all of the functional units of the wireless communication devices 10 and 10a may be realized using hardware including electronic circuits (electronic circuits or circuitry) using, for example, an LSI (Large Scale Integrated circuit), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0095] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0096] The present invention can be applied to a wireless communication device that performs wireless communication with one or more other wireless communication devices.

[0097] REFERENCE SIGNS LIST 10, 10a... wireless communication device, 11... data processing unit, 12, 12-1 to 12-2... wireless communication unit, 13, 13a... communication control unit, 14, 14a... round trip time measurement signal transmission unit, 15, 15a... round trip time measurement unit, 16... wireless communication unit, 17, 17-1 to 17-2, 18... antenna

Claims

1. A wireless communication device comprising: a communication control unit that acquires distance information indicating the transmission distance between at least one wireless communication unit among multiple wireless communication units that perform wireless communication using different or the same wireless communication method and a wireless communication device that is the currently connected communication partner; and a data processing unit that, when a switching condition for the wireless communication unit is met based on the acquired distance information, performs communication using another wireless communication unit that is not connected to the wireless communication device, or switches the wireless communication unit used in the other wireless communication device.

2. The wireless communication device according to claim 1, wherein the distance information is acquired based on results acquired multiple times at different times.

3. A wireless communication method that acquires distance information indicating the transmission distance between at least one wireless communication unit among multiple wireless communication units that perform wireless communication using different or the same wireless communication method and a wireless communication device that is the connected communication partner, and, when a switching condition for the wireless communication unit is met based on the acquired distance information, communicates using another wireless communication unit that is not connected to the wireless communication device, or switches the wireless communication unit used in the other wireless communication device.

4. A program for causing a computer to execute the following steps: an acquisition step for acquiring distance information indicating the transmission distance between at least one wireless communication unit among multiple wireless communication units that perform wireless communication using different or the same wireless communication method and a wireless communication device that is the currently connected communication partner; and a communication step for performing communication using another wireless communication unit that is not connected to the wireless communication device, or for switching the wireless communication unit used in the other wireless communication device, when a wireless communication unit switching condition is met based on the distance information acquired in the acquisition step.

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