JP7249830B2 - Wireless communication device and wireless communication method - Google Patents

Description

The present invention relates to a radio communication device, an information collection device, a radio communication method, and an information collection method.

Wireless communication traffic is increasing rapidly due to the expansion of the use of wireless LANs and the increase in devices with communication functions such as wireless surveillance cameras. is required.

In a multi-system shared frequency band such as the ISM (Industry-Science-Medical) band, since each system determines the frequency to be used in an autonomous distributed manner, the frequency channels to be used are uneven.

On the other hand, conventional wireless communication systems, for example, LTE (Long Term Evolution) Release 8 (Rel-8), which is a wireless communication system standardized by 3GPP (3rd Generation Partnership Project), uses a maximum band of 20 MHz. It is possible to communicate with

Furthermore, in LTE-A (Long Term Evolution-Advanced), which is an advanced version of LTE, the bandwidth supported by LTE is the basic unit in order to achieve further high-speed transmission while ensuring backward compatibility with LTE. A carrier aggregation (CA) technology that bundles and simultaneously uses a plurality of component carriers (CCs) is adopted, and wideband transmission of 100 MHz width can be realized using a maximum of 5 CCs (100 MHz width). However, such carrier aggregation is transmission using different channels in adjacent frequency bands.

Despite efforts to increase the speed as described above, the demand for mobile communication traffic has increased rapidly in recent years with the spread of highly functional mobile terminals such as smart phones.

As a result, in addition to the conventional expansion of the use of wireless LAN (Local Area Network), offloading to wireless LAN has progressed due to the increase in mobile data traffic due to the spread of smartphones, and unlicensed bands (2.4 GHz band, 5 GHz band) ) is experiencing a sharp increase in traffic.

In addition, due to the progress of the IoT (Internet Of Things) / M2M (Machine to Machine) society, there is concern that the above frequency band and the 920 MHz band will become even more tight, and improving the frequency utilization efficiency of these frequency bands has become an urgent issue. there is

Here, since the usage of radio resources varies depending on time, place, frequency band, radio channel, etc., as described above, a situation may occur in which only some frequency bands (or radio channels) are congested.

However, existing private wireless systems (for example, IEEE 802.11 wireless LAN) use a single frequency band or determine one band to be used in advance before performing communication. For example, IEEE802.11n presets which of the 2.4 GHz band and the 5 GHz band is to be used. For this reason, even if there are free radio resources in the existing private radio system as a whole, congestion may occur.

Here, cognitive radio technology is attracting attention in order to effectively use radio communication resources. Cognitive wireless technology means that a wireless terminal recognizes the usage status of surrounding radio waves and changes the wireless communication resource to be used according to the status. Cognitive radio technology includes a heterogeneous type in which different radio communication standards are selected and used according to the situation, and a frequency sharing type in which a radio terminal searches for an available frequency and secures a necessary communication band.

In the heterogeneous type, cognitive radio recognizes multiple wireless systems operating in the vicinity, obtains information on the availability of each system and possible transmission quality, and connects to the appropriate wireless system. In other words, the heterogeneous cognitive radio indirectly increases the utilization efficiency of frequency resources by increasing the utilization efficiency of wireless systems existing in the vicinity.

On the other hand, in the frequency-sharing type, the cognitive radio device detects the presence of frequency resources (called white space) that are temporarily or locally unused in the frequency bands in which other radio systems are operated. is detected and used for signal transmission. In other words, frequency-sharing cognitive radio directly increases the utilization efficiency of frequency resources in a certain frequency band.

As a method to solve the problem of traffic increase in the unlicensed band as described above, a plurality of wireless LAN standards using different frequency bands (for example, 2.4 GHz band wireless LAN standard and 5 GHz band wireless LAN standard) are introduced. A heterogeneous cognitive wireless approach, which is selected or used in parallel, is conceivable (for example, Patent Document 1 and Patent Document 2).

However, in this heterogeneous cognitive radio approach, it is necessary to divide transmission data as appropriate and sort in advance in which frequency band each data is to be transmitted. As a result, new problems arise, such as a large difference in transmission delay depending on the frequency band used depending on the degree of congestion in each frequency band, and a change in the order in which data arrives at the destination.

Therefore, it is desirable to realize cognitive wireless communication by sharing frequencies with existing systems in a plurality of frequency bands separated from each other, for example, a 2.4 GHz band wireless LAN and a 5 GHz band wireless LAN.

In this way, in the case of a configuration in which communication is selectively performed in one of a plurality of frequency bands separated from each other, in order to determine which frequency band to use at the next transmission timing, multiple frequencies It is necessary to sense the channels of multiple radio frequency bands in order to efficiently grasp the usage status of the radio channels of each band.

As such a channel sensing method, a technique of "cooperative sensing" in which a plurality of wireless communication devices cooperate to sense a target channel is known.

For example, in the existing cooperative sensing disclosed in Non-Patent Document 1, a single sensing target is assumed, and the results of sensing by a plurality of wireless devices are collected in order to improve the detection accuracy.

Further, for example, in the technology disclosed in Non-Patent Document 2, in cooperative sensing assuming a single sensing target, reporting of sensing results (specifically, "existing" or "not existing" sensing target) It has been done to reduce reporting of the same findings for

Japanese Patent Application Laid-Open No. 2011-211433 JP 2013-187561

Nguyen-Thanh and Koo: A cluster-based selective cooperative spectrum sensing scheme in cognitive radio. EURASIP Journal on Wireless Communications and Networking 2013 2013:176. Zeyang Dai, Jian Liu, and Keping Long, Selective-reporting-based cooperative spectrum sensing strategies for cognitive radio networks, IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 64, NO. 7, JULY 2015.

However, in the techniques disclosed in Non-Patent Document 1 and Non-Patent Document 2, each wireless device has one or more sensing targets. In other words, there is no technique for reporting the result of sensing in cooperative sensing with low overhead when the sensing is not binary sensing of whether or not a sensing target exists.

Also, in cooperative sensing, after sensing is performed by a plurality of wireless devices, a certain reporting period is provided during which the sensing results are transmitted. After the reporting period ends, the wireless device is controlled using the sensing results collected so far. Therefore, as the reporting period becomes longer, the timing for controlling the wireless device is delayed, and there is a problem that the control cannot be performed at an appropriate timing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. It is an object of the present invention to provide a wireless communication device, an information collecting device, a wireless communication method, and an information collecting method that can shorten the time.

According to one aspect of the present invention, a wireless communication device includes a channel usage status observation unit that observes the usage status of a wireless channel that performs random access control, and an information collection device that collects sensing results according to the observed usage status. a sensing result transmitting unit for transmitting to the information collecting device, a sensing result transmitting unit for receiving the sensing result transmitted from the other wireless communication device to the information collecting device, and a notification of the end of the reporting period for the sensing result transmitted from the information collecting device The result receiving unit randomly transmits the sensing results corresponding to the observations made by the device within a reporting time window whose size decreases as the appropriateness indicating that the wireless channel is suitable for use regarding the sensing results decreases. and a sensing result transmitting unit that controls the sensing result transmission unit so that the sensing result of the device is transmitted at the transmission time determined by the transmission time determination unit, and the sensing result of the device is transmitted to another wireless device. If the appropriateness is higher than the sensing result received from the communication device, control the sensing result transmission unit so that the sensing result of its own device is not transmitted, and when the notification of the end is received, the reporting period is extended. and a transmission control unit that terminates, and the transmission time determination unit sets the reporting time that ends earlier as the non-reporting period, which is the period until the first sensing result is received from the other wireless communication device, becomes longer. Update the send time to be the send time within the window.

Preferably, the radio communication apparatus transmits signals using a plurality of radio channels on which random access control is performed in each of a plurality of frequency bands separated from each other, and transmits transmission data in a plurality of frequency bands. A digital signal processing section for dividing into a plurality of partial data corresponding to each and generating a transmission packet for each frequency band, and a digital signal processing section provided for each frequency band for processing the digital signal generated by the digital signal processing section. a plurality of high-frequency processing units for converting into high-frequency signals for each corresponding frequency band; and a local oscillator provided in common to the plurality of high-frequency processing units for generating a clock signal used by the plurality of high-frequency processing units. The channel usage observation unit observes the usage of a plurality of wireless channels in a plurality of frequency bands, and the sensing result reception unit integrates the sensing results from the plurality of wireless communication devices. Sensing information is also received from the information collecting device, the digital signal processing unit and the high frequency processing unit are controlled based on the integrated sensing information, and each partial data is synchronized as packets for each of multiple frequency bands by multiple wireless channels. and an access control unit for transmitting at the same timing.

Preferably, the transmission control unit controls transmission of sensing results for each wireless channel.

Preferably, the transmission time determination unit updates the transmission time so that each time the non-reporting period increases by the unit period, the transmission time is within the reporting time window whose end is earlier by a predetermined period.

According to another aspect of the present invention, the information collection device provides sensing results according to the usage status observed from a plurality of wireless communication devices observing the usage status of a wireless channel on which random access control is performed, Decide on a reporting time window where the less appropriate the radio channel is for use, the smaller the size, and the longer the period until the first sensing result is received, the earlier the termination. The longer the non-reporting period, which is the period until the first sensing result is received by the receiving unit that receives the sensing result transmitted at the time of transmission and the receiving unit receives the sensing result, the shorter it becomes. , an acquisition unit that acquires a report end time that becomes shorter as the appropriateness of the received sensing result is lower, and a shortest report end that is the shortest report end time according to one or more report end times acquired by the acquisition unit. A specifying unit for specifying time, and a transmitting unit for notifying a plurality of wireless communication devices of the end of the sensing result reporting period when the shortest reporting end time has arrived.

Preferably, the information collecting device further includes a generator that generates integrated sensing information by integrating the sensing results received by the receiver, and the transmitter also transmits the integrated sensing information to the plurality of wireless communication devices.

Preferably, the transmission of integrated sensing information is notification of the end of the reporting period.

Preferably, the acquisition unit acquires the reporting end time using the reporting time window according to the received sensing result and the non-reporting period.

According to another aspect of the present invention, a wireless communication method includes the steps of observing the usage status of a wireless channel on which random access control is performed, and receiving sensing results transmitted from another wireless communication device to an information collection device. and randomly determining the timing of transmitting the sensing result according to the observation by the own device in the reporting time window whose size decreases as the appropriateness indicating that the wireless channel is suitable for use regarding the sensing result decreases. Step and when the sensing result of the device is more appropriate than the sensing results received from other wireless communication devices up to the time of transmission, the sensing result of the device is not transmitted to the information collection device , if the sensing result of its own device is less appropriate than the sensing result received from another wireless communication device up to the time of transmission, the sensing result of its own device is transmitted to the information collecting device at the time of transmission. a step of receiving a notification of the end of a sensing result reporting period transmitted from an information collecting device; a step of ending the reporting period when the notification of the end is received; and updating the transmission time point so that the transmission time point is within the reporting time window that ends earlier as the non-reporting period, which is the period until the first sensing result is received, becomes longer.

According to another aspect of the present invention, an information collection method provides a sensing result according to the observed usage status from a plurality of wireless communication devices observing the usage status of a wireless channel on which random access control is performed, comprising: Decide on a reporting time window where the less appropriate the radio channel is for use, the smaller the size, and the longer the period until the first sensing result is received, the earlier the termination. The step of receiving the sensing result transmitted at the time of transmission, and the received sensing result, the longer the non-reporting period, which is the period until the first sensing result is received, the shorter it is. a step of acquiring a reporting end time that becomes shorter as the appropriateness of the sensing result becomes lower; a step of identifying the shortest reporting end time, which is the shortest reporting end time, according to the acquired one or more reporting end times; and notifying the plurality of wireless communication devices of the end of the sensing result reporting period when the reporting end time has arrived.

According to the present invention, reporting of sensing results in cooperative sensing can be realized with low overhead, and the reporting period of sensing results can be shortened.

Then, according to the present invention, for example, by using the results of cooperative sensing, it is possible to flexibly select channels of multiple frequency bands or use them simultaneously, so that wireless resources can be utilized without waste and frequency utilization efficiency can be improved. It becomes possible.

FIG. 2 is a diagram showing the concept of channel sensing in communication between the own station and the partner station; FIG. 4 is a conceptual diagram when cooperative sensing is performed; 1 is a block diagram showing the configuration of a wireless communication device according to this embodiment; FIG. 1 is a block diagram showing the configuration of an information collecting device according to an embodiment; FIG. 4 is a flowchart for explaining processing of a wireless communication device; 4 is a flowchart for explaining processing of the information collecting device; It is a conceptual diagram for comparing the conventional distributed sensing method and the autonomous decentralized cooperative sensing method of the proposed method. FIG. 10 is an explanatory diagram for comparing selective reporting without control of transmission time and selective reporting with control of transmission time; FIG. 4 is a diagram for explaining a sensing period, a reporting period, and the like; FIG. 4 is a conceptual diagram for explaining processing for early ending a reporting period; FIG. 10 is a conceptual diagram for explaining processing for moving forward the transmission time when the unreported time is long; FIG. 10 is a conceptual diagram for explaining processing for moving forward the transmission time when the unreported time is long; FIG. 10 is a conceptual diagram for explaining processing for moving forward the transmission time when the unreported time is long; FIG. 10 is a conceptual diagram for explaining processing for moving forward the transmission time when the unreported time is long; FIG. 10 is a conceptual diagram for explaining a process of calculating a post-update transmission time using a pre-update transmission time; 1 is a conceptual diagram for explaining radio channels in a plurality of frequency bands separated from each other; FIG. 1 is a conceptual diagram for explaining the configuration of a radio communication system according to this embodiment; FIG. FIG. 4 is a diagram for explaining a specific example for mapping transmission data to a plurality of bands, transmitting the data, and collectively receiving and integrating the data on the receiving side; FIG. 2 is a functional block diagram for explaining the configuration of transmitting apparatus 1000 of the present embodiment; FIG. FIG. 3 is a functional block diagram for explaining an example of a more detailed configuration of transmission device 1000. FIG. 2 is a functional block diagram for explaining the configuration of receiving apparatus 2000 of this embodiment. FIG. FIG. 3 is a functional block diagram for explaining an example of a more detailed configuration of receiving device 2000. FIG.

Configurations of a wireless communication system, a wireless communication device, and an information collecting device according to embodiments of the present invention will be described below. In the following embodiments, constituent elements and processing steps denoted by the same reference numerals are the same or equivalent, and description thereof will not be repeated unless necessary.

In the following, as an example for explaining the wireless communication device of the present invention, a plurality of existing unlicensed bands that are widely separated from each other as described above (for example, the 920 MHz band used for IoT, etc., 2.4 GHz band and 5 GHz band), an embodiment will be described, taking as an example a transmitting apparatus in a wireless communication system capable of performing cognitive wireless communication by sharing frequencies with existing systems.

In addition, hereinafter, "carrier sense" refers to sensing for detecting the presence or absence of a signal in the target radio channel and determining the transmission timing by virtual carrier sense involving power detection or decoding of received signals. In addition to sensing as carrier sensing, "channel sensing" means sensing for executing communication monitoring and the like in order to grasp the usage status of the target channel.

[Embodiment]
In the following, for the purpose of explaining this embodiment, in the case of a configuration in which communication is performed by random access control in a plurality of frequency bands separated from each other, in order to determine when the next transmission timing should be, A configuration for simultaneous channel sensing of multiple channels in the target band will be described.

However, it is not essential for the present invention to communicate using multiple frequency bands at the same time. , in order to determine which frequency band to use at the next transmission timing, it is also possible to apply a configuration in which simultaneous channel sensing is performed on multiple channels of the target band.

In addition, it is not essential for the present invention to perform channel sensing on a plurality of wireless channels. For example, in order to determine the frequency band for communication, it is also applicable to a configuration in which channel sensing is performed on one wireless channel. It is possible to Moreover, it is not essential for the present invention to perform channel sensing of the wireless channel. you can go

Furthermore, it is not essential for the present invention to perform substantive communication using a radio channel on which random access control is performed. It is also possible to apply to a configuration in which general communication is not performed.

FIG. 1 is a diagram showing the concept of channel sensing in communication between a local station and a remote station.

When the local station 10 intends to transmit to the remote station 20, it first performs channel sensing in order to confirm the usage status of a plurality of channels in the usage band.

Here, if there are other communication devices 30.1 to 30.4 using any of the available band channels in the vicinity of the local station 10 or the remote station 20, they become sources of interference, Therefore, the own station 10 detects and uses a free frequency band channel to communicate with the opposite station 20. FIG.

FIG. 2 is a conceptual diagram for explaining cooperative sensing. FIG. 2 shows a case where cooperative sensing is performed within a BSS as an example.

Here, "BSS (Basic Service Set)" means one wireless base station (access point AP) and a wireless LAN client terminal under its control (which is within the range of radio waves of that AP) in the wireless LAN infrastructure mode. STA).

For efficient wireless communication, it is necessary for each wireless communication device to sequentially grasp the propagation status and wireless resource usage status in the wireless network to which the device belongs, and to perform access control based on the results. However, it is impractical from the viewpoint of cost and the like to try to perform sensing at each location of the wireless network with a single wireless communication device.

According to cooperative sensing, by exchanging and sharing sensing results among multiple wireless communication devices, it is possible to sense more wireless channels than the wireless channel sensing information obtained by real-time sensing by a single wireless communication device. information can be obtained.

Although not particularly limited, the following situation will be described below. The information to be exchanged does not necessarily have to be real-time information, but should be sensing results within a certain period of time. However, each wireless communication device may basically perform sensing itself all the time.

Also, the radio base station AP has a radio communication function in a radio communication system equivalent to that of the radio communication apparatus STA, which will be described later, and a processor and a memory for integrating the results of cooperative sensing. Since the configuration of the processor and memory is well known, the explanation is omitted.

Referring to FIG. 2, the protocol for exchanging information within the BSS can have the following configuration.

The sensing results are exchanged between the radio base station AP (information collection device) and the radio communication devices STA1 to STA5 from the viewpoint of efficient information collection and deployment of information within the BSS.

In this case, the wireless communication devices STA1 to STA5 report the sensing results to the wireless base station AP as indicated by the solid line arrows in FIG. The integrated sensing information is developed in subordinate wireless communication devices STA1 to STA5, as indicated by dashed arrows in FIG.

FIG. 3 is a block diagram showing a configuration related to transmission and reception of sensing results in wireless communication apparatus 200. As shown in FIG. Radio communication apparatus 200 according to the present embodiment includes channel usage observation section 201 , sensing result transmission section 202 , sensing result reception section 203 , transmission time determination section 204 and transmission control section 205 . In the present embodiment, radio communication apparatus 200 transmits signals using a plurality of radio channels on which random access control is performed in each of a plurality of frequency bands separated from each other. but it doesn't have to be. Radio communication apparatus 200 may transmit a signal using any radio channel on which random access control is performed. A configuration for performing communication using a plurality of radio channels in a plurality of frequency bands separated from each other will be described later.

In the present embodiment, an example in which an information collection device (details will be described later) to which sensing results are transmitted is a wireless base station (access point AP) will be described, but the information collection device is not limited to this. Instead, it may be, for example, a device for collecting sensing results. The information collection device collects the results of channel sensing, integrates them, and transmits them to each wireless communication device 200 .

A channel usage status observation unit 201 observes the usage status of a radio channel for which random access control is performed. When radio communication apparatus 200 transmits signals using a plurality of radio channels on which random access control is performed in each of a plurality of frequency bands separated from each other, channel usage status observation section 201 may observe the usage status (such as availability of each wireless channel) of each frequency band (one or more wireless channels in each frequency band).

The sensing result transmission unit 202 transmits sensing results according to the usage state observed by the channel usage state observation unit 201 to the information collection device 300, which will be described later. The sensing result may be generated by the channel usage status observation unit 201 or by the sensing result transmission unit 202, for example. Here, the sensing results include, for example, the following. Needless to say, sensing results are not limited to the following examples.
a1) Channel utilization rate (channel occupancy rate)
a2) Frame error rate a3) Number of interference source terminals a4) Number of hidden terminals

The sensing result may be, for example, any one of a1) to a4) above, or any combination of two or more, and a value generated using one or more of them (e.g., a1 above) to a4) as an argument, etc.).

Channel Occupancy Ratio (COR) can be calculated by dividing the busy period in the observation period by the observation period. In place of the channel utilization rate, for example, an idle rate obtained by dividing the idle state period in the observation period by the observation period, or an idle/idle rate obtained by dividing the idle state period in the observation period by the busy state period in the observation period A busy ratio or the like may be used as the sensing result. Also, when the sensing result is transmitted frequently, the sensing result may be information indicating whether the device is in a busy state or an idle state, for example. If the sensing result is the channel utilization rate, the observation of the radio channel utilization may be an observation of whether the radio channel is busy or idle.

The frame error rate may be the percentage of frames received by observation that could not be demodulated correctly. In this case, the observation of the usage status of the radio channel may be reception or demodulation of the radio signal.

The number of terminals that are sources of interference can be obtained by demodulating radio signals of other cells (cells different from the cell to which the device belongs) and counting the number of unique terminal identifiers such as MAC addresses. In this case, the observation of the usage status of the radio channel may be reception or demodulation of the radio signal.

The number of hidden terminals may be obtained according to reception of CTS (permission to send) sent in response to RTS (request to send) not received by the device itself, or data not received by the device itself. may be obtained in response to receiving an ACK sent from the access point AP to the . For example, the number of hidden terminals for the own device may be obtained by counting the number of unique terminal identifiers such as MAC addresses of destinations included in such CTS and ACK. RTS and CTS will be described later. In this case, the observation of the radio channel usage may be reception and demodulation of RTS, CTS, ACK, and the like.

If the sensing results are the channel utilization rate, the frame error rate, the number of terminals that are sources of interference, and the number of hidden terminals, the higher the channel utilization rate, etc., the more suitable the radio channel is for use. Therefore, the lower the channel utilization rate, etc., the higher the appropriateness. The adequacy according to the channel utilization rate may be calculated as, for example, "1-channel utilization rate". On the other hand, when the sensing result is the idle rate, the higher the idle rate, the higher the appropriateness.

The sensing result receiving unit 203 receives sensing results transmitted from another wireless communication device 200 to the information collecting device 300 . The sensing result receiving unit 203 also receives a notification of the end of the sensing result reporting period transmitted from the information collecting device 300 . Also, the sensing result receiving unit 203 may receive integrated sensing information, which is a result of integrating sensing results from a plurality of wireless communication devices 200 , from the information collecting device 300 .

The transmission time determination unit 204 randomly determines the transmission time of the sensing result according to the observation by the own device in the reporting time window whose size decreases as the appropriateness of the sensing result of the own device becomes lower. This determined transmission time may be hereinafter referred to as the "initial transmission time". In addition, the longer the non-reporting period, which is the period until the first sensing result is received from another wireless communication device 200, the earlier the transmission time point within the reporting time window. Update the transmission time so that This updated transmission time may be hereinafter referred to as "updated transmission time". Note that the start of the reporting time window usually coincides with the start of the reporting period. Also, the first sensing result is the first sensing result received in a certain reporting period. Therefore, the non-reporting period is the period from the beginning of a certain reporting period until the first sensing result is received, and can vary from reporting period to reporting period. In addition, since it is not always possible for all other wireless communication devices 200 belonging to the same BSS to receive the sensing result transmitted from a certain wireless communication device 200, the non-reporting period may differ for each wireless communication device 200. could be. Also, the transmission time point may be indicated by the length of time from a certain reference time point, or may be indicated by a time pinpointing the transmission time point. A certain reference point in time may be, for example, the beginning of the reporting period (beginning point). The details of the determination of the transmission time point and the update process will be described later.

The transmission control unit 205 controls the sensing result transmission unit 202 so that the sensing result of its own device is transmitted at the transmission time determined by the transmission time determination unit 204 . As described above, the time point of the first transmission is randomly determined in the reporting time window whose size decreases as the appropriateness of the sensing result of the device itself decreases. Therefore, sensing results with lower appropriateness are controlled to be probabilistically earlier transmission time points (transmission timings), and sensing results with higher appropriatenesses are controlled to be probabilistically later transmission time points. Such transmission timing control may be hereinafter referred to as "transmission timing control". Further, by transmitting the sensing result according to the updated transmission time, the timing of transmitting the sensing result is at least probabilistically brought forward. Therefore, transmitting the sensing result according to the updated transmission time is sometimes called "forward control of the transmission time". In addition, when the sensing result of its own device is more appropriate than the sensing result transmitted from another wireless communication device 200 and received by the sensing result receiving unit 203, the transmission control unit 205 , the sensing result transmitting unit 202 is controlled so as not to transmit the sensing result of . This is because, in such a case, there is no point in transmitting the sensing result of the own device. Note that the control of transmission/non-transmission of sensing results by the transmission control unit 205 may be hereinafter referred to as “selective reporting”. Further, the transmission control unit 205 ends the reporting period when the sensing result receiving unit 203 receives the end notification transmitted from the information collecting device 300 .

FIG. 4 is a block diagram showing a configuration related to reception of sensing results in information collecting apparatus (radio base station) 300. As shown in FIG. Information collecting apparatus 300 according to the present embodiment includes receiving section 301 , acquiring section 302 , identifying section 303 , generating section 304 and transmitting section 305 . When the information collection device 300 performs communication using a plurality of radio channels on which random access control is performed in each of a plurality of frequency bands separated from each other, the information collection device 300 is a transmission device described later. 1000 or the receiving apparatus 2000 may have the same configuration. Further, the information collection device 300 may have a configuration for performing processing as an access point AP.

The receiving unit 301 receives sensing results according to the observed usage status from a plurality of wireless communication apparatuses 200 that observe the usage status of wireless channels that are subjected to random access control. The sensing result is transmitted at the transmission time determined in the reporting time window, which becomes smaller in size as the pertinence of the sensing result becomes lower, and ends earlier as the period until the first sensing result is received becomes earlier. It is a thing. The receiver 301 normally receives at least one sensing result in the reporting period.

Acquisition unit 302 acquires the report end time corresponding to the sensing result received by reception unit 301 . This report end time indicates the end of the point in time when sensing results having the same appropriateness as the received sensing results are transmitted. The acquisition unit 302 acquires, for example, the reporting end time of the received sensing result, which becomes shorter as the non-reporting period becomes longer, and becomes shorter as the appropriateness of the received sensing result becomes lower. The shortening of the reporting end time means that the reporting end time approaches the start point of the reporting period in the reporting period. Acquisition unit 302 acquires the end of the reporting time window that is considered to be used to determine the transmission time point of the received sensing result (that is, the non-reporting period acquired by information collection device 300 and the sensing result received by reception unit 301). The end of the reporting time window obtained using the adequacy of ) may be the reporting end time. Strictly speaking, as will be described later, the end of the report time window used by acquisition section 302 to acquire the report end time is the end of the report time window used to determine the transmission time of the received sensing result. The end may be different. This is because not all wireless communication devices 200 can receive the sensing results received by the information collecting device 300 . However, even in such a case, the end of the reporting time window used by acquisition section 302 to acquire the reporting end time may be later than the end of the reporting time window used by wireless communication device 200 to determine the transmission time. Therefore, an appropriate reporting end time at which the lowest appropriate sensing result in the BSS can be received will be obtained. Acquisition unit 302 normally acquires the report end time corresponding to the received sensing result each time receiving unit 301 receives the sensing result. Calculation of the specific reporting end time will be described later.

The specifying unit 303 specifies the shortest report end time, which is the shortest report end time, according to one or more report end times acquired by the acquisition unit 302 . If one reporting end time is obtained, it becomes the shortest reporting end time. If two or more report end times are obtained, the shortest one will be the shortest report end time. For example, the specifying unit 303 may update the shortest report end time each time the acquisition unit 302 acquires the report end time. Note that if the newly obtained report end time is longer than the shortest report end time so far, no update is performed. Also, the shortest reporting end time may be stored in a recording medium (not shown).

The generating unit 304 generates integrated sensing information that integrates the sensing results received by the receiving unit 301 . The generation unit 304 may generate the integrated sensing information by updating the sensing result with the lowest appropriateness each time the sensing result is received, or generate the integrated sensing information after receiving all the sensing results. may In the former case, for example, the generation unit 304 may hold the channel sensing result with the lowest appropriateness for each wireless channel. Therefore, when the sensing result reported from wireless communication device 200 for a certain wireless channel is less appropriate than the previously reported sensing result, generating section 304 updates the held sensing result, If the sensing result reported from the communication device 200 is not less appropriate than the previously reported one, the held sensing result may not be updated. Note that when the held sensing results become old with the passage of time, the generation unit 304 updates the held sensing results to newly reported ones regardless of the contents of the sensing results. You may This is for holding the latest sensing results. More specifically, the sensing results may be updated so that the least appropriate sensing results are retained for each reporting period. Integration of sensing results may be performed in this manner. Note that the integrated sensing information may be stored in a recording medium (not shown).

Transmitting section 305 notifies a plurality of wireless communication devices 200 of the end of the sensing result reporting period when the shortest reporting end time has arrived. Note that the notification of the end of the reporting period to the plurality of wireless communication devices 200 may or may not be made by transmitting integrated sensing information, for example. In the former case, the transmission unit 305 transmits integrated sensing information to each wireless communication device 200 as a notification of the end of the reporting period when the shortest reporting end time arrives. Then, each wireless communication device 200 may determine that it has received the notification of the end of the reporting period when it receives the integrated sensing information. In addition, when the notification of the end of the reporting period and the transmission of the integrated sensing information are separate, the transmission unit 305 also transmits the integrated sensing information to the plurality of wireless communication devices 200 separately from the notification of the end of the reporting period. may be sent to The transmission of the integrated sensing information may occur after notification of the end of the reporting period.

Note that the report end time and the shortest report end time may be information indicating a period. In that case, it is determined that the shortest reporting end time has arrived when a period corresponding to the shortest reporting end time has elapsed from the start point of the reporting period. Also, the report end time and the shortest report end time may be time (for example, 18:45:15.025). In that case, for example, the acquisition unit 302 may set the report end time to the time when the length of the report time window has elapsed from the time of the start of the report period, that is, the time corresponding to the end of the report time window. . If the report end time or the shortest report end time is time, it is determined that the shortest report end time has arrived when the current time reaches the shortest report end time.

In addition, it is preferable that the latest sensing result is reported to the access point AP. Therefore, if the sensing result of its own device is more appropriate than the sensing result of another wireless communication device within a predetermined period of time, the transmission control unit 205 does not transmit the sensing result of its own device. Alternatively, the sensing result transmission unit 202 may be controlled. That is, even if the sensing result of the device itself is more appropriate than the sensing result transmitted before the predetermined time, the sensing result of the device itself will not be sent within the predetermined time. If a sensing result with a low degree of appropriateness has not been transmitted from another device, the sensing result from its own device will be transmitted. The predetermined time may be, for example, a predetermined period of time, or a period of time up to the switching point immediately before the control point (comparison point) for the reporting period (from the reporting period switching point to the control point). period until the point in time). In the latter case, the process of comparing sensing results between the self device and other devices is reset every reporting period. In this embodiment, this case will be mainly described. By controlling transmission of sensing results as described above, the access point AP can always receive the latest sensing results. Since each wireless communication device performs wireless communication by random access control, strictly speaking, there is a time lag (waiting time) between acquisition of the sensing result and transmission. It may be determined that the time when the result is received is the time when the sensing result is obtained. This is because it is considered unlikely that the two time points will diverge significantly. Further, when the sensing result includes information indicating the time point of sensing or the time point of acquisition of the sensing result, the above control may be performed using the information.

Next, the selective reporting, the control of the time of transmission, and the forward control of the time of transmission will be described more specifically.

FIG. 7 is a diagram for comparing the conventional distributed sensing method and the autonomous distributed cooperative sensing method of the present embodiment (proposed method). Here, it is assumed that the sensing result is the channel utilization rate (COR), and the numerical values written near each STA 11 to 15 in the figure are the channel utilization rates.

Referring to FIG. 7(a), in the conventional sensing method, sensing results are transmitted from each of five wireless communication devices STA11 to STA15 belonging to BSS1. In addition, in radio channel control in a certain BSS, the worst value (in the case of FIG. 7, the channel utilization rate of STA 11 is "60%") is used for the use of the radio channel. Therefore, the sensing results transmitted from the wireless communication devices STA12 to STA15 are redundant information, and the transmission of the redundant information unnecessarily consumes wireless resources and causes an increase in overhead.

Referring to FIG. 7B, in the autonomous decentralized cooperative sensing method according to the present embodiment, each wireless communication device 200 receives the sensing result transmitted from another wireless communication device 200, and based on the sensing result, Only the sensing result with the worst value is transmitted to the access point AP1 (information collecting device 300). Specifically, the transmission control unit 205 ensures that the sensing result obtained by the observation by the own device, that is, the observation by the channel usage status observation unit 201 is transmitted to another wireless communication device by the time of transmission of the sensing result of the own device. When the sensing result transmitted from the device is higher than the sensing result received by the sensing result receiving unit 203 up to the time of transmission of the sensing result of the device itself, the sensing result of the device is not transmitted. It controls the result transmission unit 202 . Further, when the sensing result of the device itself is less appropriate than the sensing result of another device received up to the time of transmission of the sensing result of the device itself, the transmission control unit 205 sends the sensing result of the device itself. The sensing result transmission unit 202 is controlled to transmit the In addition, when the appropriateness of the sensing result of the own device and the sensing result of the other device are the same, the transmission control unit 205 may control to transmit the sensing result of the own device, or not to transmit the sensing result of the own device. Although it may be controlled, from the viewpoint of suppressing the consumption of radio resources, it is preferable to control so as not to transmit. Also, the transmission control unit 205 may receive the sensing result of its own device, for example, from the channel usage status observation unit 201 or from the sensing result transmission unit 202 .

As described above, even if the sensing results are selectively reported, if the reporting order of the sensing results in the BSS is inappropriate, redundant information will be transmitted. Resources will be unnecessarily consumed. This will be described with reference to FIG.

FIG. 8 is a diagram for comparing the case of controlling the transmission time (reporting time) and the case of not controlling the selective reporting of sensing results. In FIG. 8, the upward arrows indicate the transmission timing of the sensing results and the channel utilization rate (COR) indicated by the sensing results. Note that when the sensing result is the channel utilization rate, the higher the channel utilization rate, the lower the appropriateness. Also, dashed arrows indicate that sensing results were not transmitted as a result of selective report transmission control.

With reference to FIG. 8(a), in the selective reporting of sensing results without controlling the transmission time, if transmission is performed in the BSS in order of lowest channel utilization rate, the sensing results are appropriately transmitted. cannot be suppressed to Specifically, in FIG. 8A, since the first to third and sixth sensing results are transmitted, only the effect of suppressing the transmission of the fourth and fifth sensing results is obtained. There will be no.

On the other hand, in FIG. 8B, the transmission control unit 205 controls the timing of transmitting the sensing result so that the timing of transmitting the sensing result becomes earlier as the appropriateness of the sensing result of the device itself is lower. Therefore, ideally, the sensing results are transmitted in descending order of channel utilization (COR) (that is, in descending order of appropriateness), and as shown in FIG. Since the transmission is not performed, it is possible to efficiently suppress the transmission of the sensing result. It should be noted that controlling the timing of sending the sensing results so that the timing of sending the sensing results is earlier as the appropriateness of the sensing results of the own device is lower means that when looking at the transmission of the sensing results as a whole, the Alternatively, a sensing result with a lower degree of appropriateness may be transmitted earlier. Therefore, the control of the transmission time is considered to control the transmission time of the sensing result so that the lower the appropriateness of the sensing result of the device, the higher the probability that the transmission time of the sensing result will be earlier. good too. Specifically, when the time to transmission is randomly determined in the reporting time window according to the degree of appropriateness, due to the randomness, the timing of transmitting individual sensing results has a high degree of appropriateness. It is possible that the less appropriate sensing result will be sent earlier, but probabilistically, the less appropriate sensing result will be sent earlier. In this way, it may be considered that the control of the transmission time is stochastically controlled so that the less appropriate sensing result is, the earlier the transmission time is set in each wireless communication device 200 .

Next, a specific description will be given of a technique for controlling the transmission time points as described above. Here, a case will be described in which the transmission control unit 205 randomly determines the time until transmission in the report time window whose size decreases as the appropriateness of the sensing result according to the observation by the own device becomes lower. First, let _{RTW_0} be the default reporting time window length (size). The reporting time window may be the time interval (0, RTW ₀ ) or the time interval (0, RTW ₀ ), where the parentheses indicate that the end points are not included, Square brackets indicate that the endpoints are included.The default reporting time window length RTW ₀ can be, for example, a fixed value or a value that varies depending on the communication situation. In the latter case, for example, RTW ₀ may be longer when low-delay requirements are not high, and RTW ₀ may be shorter when low-delay requirements are high. The length of the reporting time window may be similar to the contention window (CW) size, including, but not limited to, the default reporting time window length RTW ₀ may be, for example, several ms to several tens of ms, or may be several hundred ms. Define like a formula.
RTW (appropriateness)=appropriateness×RTW ₀ +base

Here, the appropriateness is preferably normalized to be a real number from 0 to 1. Also, base is an offset for preventing the size of the reporting time window from becoming 0 when the appropriateness is 0, and is a positive real number sufficiently small compared to RTW ₀ . If the sensing result is the channel utilization (COR), the appropriateness can be set to 1-COR, so the reporting time window according to the channel utilization is a time interval of (0, RTW _COR ), Alternatively, it may be a time interval of (0, RTW _COR ], where RTW _COR is given by the following equation, and 0≦COR≦1.
RTW _COR = (1-COR) x RTW ₀ + base

In this case, the lower the channel utilization, the larger the size of the reporting time window, and the higher the channel utilization, the smaller the size of the reporting time window. Therefore, the size of the reporting time window is monotonically decreasing with respect to channel utilization (ie monotonically increasing with respect to adequacy). In addition, by the transmission control unit 205 randomly (for example, uniform random) determining the time until the transmission time in such a reporting time window, the higher the channel utilization rate according to the observation in the own device, the more the channel As the transmission time point of the utilization rate becomes earlier and the channel utilization rate according to observation by the device itself becomes smaller, the transmission time point of the channel utilization rate is controlled to be later. More generally, regarding the appropriateness, the higher the appropriateness according to the observation by the own device, the longer the time until the sensing result is sent, and the lower the appropriateness according to the observation by the own device. , the time to transmit the sensing result becomes shorter. In the autonomous decentralized cooperative sensing system shown in FIG. 7(b), it is assumed that such control of transmission timing is also performed. Therefore, each of the wireless communication devices STA11 to STA15 in FIG. 7(b) randomly determines the transmission time point in the reporting time window according to the sensing result (channel utilization rate) of each wireless communication device, If the appropriateness of the sensing result sent from the wireless communication device is lower than the appropriateness of the sensing result of the own device, the sensing result of the own device is not sent and the appropriateness of the sensing result of the own device is higher than the appropriateness of the sensing result of the own device If it is higher, it transmits the sensing result of its own device.

In FIG. 7(b), it is assumed that information transmitted from other wireless communication devices can be mutually received within the range surrounded by the dashed line. That is, it is assumed that the wireless communication devices STA11, STA12, and STA15 can receive the sensing results transmitted by the other devices. Also, it is assumed that the wireless communication devices STA13 and STA14 can receive the sensing result transmitted by each of the other devices. In addition, in FIG. 7(b), the size of the reporting time window according to each channel utilization is shown in parentheses on the right side of the channel utilization. Also, here, it is assumed that the sensing results are transmitted to the access point AP1 in order from the smallest size of the reporting time window, that is, in the order of the wireless communication devices STA11, STA12, STA13, STA14, and STA15. In such a situation, first, the wireless communication device STA11 transmits the sensing result (60%) of its own device to the access point AP1. Next, the wireless communication device STA12 receives the sensing result (60%) transmitted by the wireless communication device STA11, and the sensing result corresponding to the observation by its own device is 40%, which is better than the result already transmitted. Since it is a value (that is, the degree of appropriateness is high), the sensing result is not transmitted. On the other hand, since the wireless communication device STA13 cannot receive the sensing result transmitted from the wireless communication device STA11, it transmits the sensing result (30%). Also, the wireless communication device STA14 receives the sensing result (30%) transmitted by the wireless communication device STA13, and the sensing result corresponding to the observation by its own device is 20%, which is a better value than the result already transmitted. Therefore, the sensing result is not transmitted. Similarly, the wireless communication device STA15 does not transmit its own sensing result. As a result, the sensing results are transmitted only from the two wireless communication devices STA11 and STA13, and the number of sensing result transmissions can be reduced compared to the conventional case. Therefore, overhead associated with sensing result reporting can be significantly reduced, and unnecessary consumption of radio resources can be suppressed. In addition, since each wireless communication device autonomously controls transmission/non-transmission of the sensing result, unnecessary communication is not generated for the control. In addition, since each wireless communication device autonomously controls transmission/non-transmission of sensing results, scalability can be ensured.

FIG. 9 is a conceptual diagram showing an example of the relationship between periodic sensing and periodic reporting (transmission of sensing results to the information collecting device). Referring to FIG. 9A, the length of time of the sensing period in each wireless communication device is determined, and as an example, sensing in each wireless communication device is started in response to an instruction from the access point AP. . Therefore, the start point and end point of each sensing period in each wireless communication device are the same. A sensing result corresponding to the observation of the radio channel during the sensing period is transmitted to the access point AP during the reporting period. In the case where control related to the end of the reporting period (this control will be described later) is not performed, the temporal length of the reporting period is constant. Since the reporting period corresponding to the sensing period starts after the sensing period ends, if the sensing period is synchronized in each wireless communication device, the reporting period is also synchronized in each wireless communication device. It will be. The transmission is performed according to report timing (transmission time point) randomly selected in each wireless communication device. The transmission timing is determined by transmission control section 205 as described above. The time to transmission time randomly determined using the reporting time window may be the time from the beginning of each reporting period to the time of transmission. However, as described above, only when the sensing result of the own device is worse than the sensing result already transmitted from another wireless communication device, the sensing result of the own device is reported, and the other wireless communication device has already If the sensing result transmitted from the device is worse than the sensing result of the own device, the sensing result of the own device is not reported. According to the control, the number of reports of sensing results is reduced. When the reporting period ends, the integrated sensing information generated in the access point AP is transmitted to each wireless communication device according to the reporting result. Then, wireless communication using a wireless channel corresponding to the integrated sensing information is performed between each wireless communication device and the access point AP (communication period). After that, the sensing period, the reporting period, etc. will be repeated. Note that the default reporting time window size RTW ₀ is, for example, the length of the reporting period (as described below, the reporting period may be shortened, so this reporting period length may be the maximum length of the reporting period). length) or less than the length of the reporting period. In the latter case, for example, the default reporting time window size may be the result of subtracting the base length from the reporting period length, or it may be less.

Note that, as shown in FIG. 8(b), when the transmission timing is controlled, the sensing result may be reported early in the reporting period. In this way, when a sensing result with a low degree of appropriateness is reported early in the reporting period, unnecessary waiting time is performed in the reporting period after the report. On the other hand, if the reporting period is uniformly shortened, when the appropriateness of the observation results of each wireless communication device in the BSS is high, the timing of transmitting the sensing results will be delayed, and the access point AP may not be able to receive the sensing results.

Therefore, the information collection device, which is the access point AP, may determine the end of the reporting period as follows. FIG. 10 is a diagram for explaining control regarding the end of the reporting period. Note that in FIG. 10, the starting point of the reporting period is set to time "0". Also in FIG. 10, as in FIG. 7, it is assumed that each wireless communication device is observed. In FIG. 10, it is assumed that the wireless communication device STA11 transmits the channel utilization rate "60%", which is the sensing result, to the access point AP at time T21. The access point AP can then use the received sensing results to calculate the length of the reporting time window used in determining the transmission time point in the wireless communication device STA11. Assume here that the length of the reporting time window is T22. Specifically, the length of the reporting time window is calculated by substituting the relevance into the above RTW (relevance) formula and substituting the channel utilization rate (COR) into the above RTW _COR formula. can do. Once the length of the reporting time window has elapsed from the start of the reporting period, no further relevance will be reported that is lower than the relevance corresponding to that reporting time window. This is because the lower the relevance, the shorter the length of the reporting time window. Therefore, the acquisition unit 302 of the access point AP (information collection device 300) calculates the reporting end time according to the sensing result each time the sensing result is received. The reporting end time is a period corresponding to the length of the reporting time window according to the sensing result. Then, when two or more sensing results are received, the specifying unit 303 acquires the shortest report end time, which is the shortest report end time, among the two or more calculated report end times. For example, in FIG. 10, when the wireless communication device STA12 transmits the sensing result to the access point AP before the wireless communication device STA11, the access point AP transmits the reporting end time "T23" according to the sensing result. Calculate In this case, since there is only one report end time, the shortest report end time is set to "T23". Next, when the wireless communication device STA11 transmits the sensing result, the access point AP calculates the reporting end time "T22". Then, since T22<T23, the access point AP updates the shortest reporting end time to "T22".

After that, when the elapsed time from the start of the reporting period reaches T22 and the shortest reporting end time "T22" arrives, the access point AP notifies each wireless communication device of the end of the reporting period. The sensing result receiving unit 203 also receives a notification of the end of the sensing result reporting period transmitted from the information collecting device 300 . When the notification of the end of the reporting period is received, the transmission control section 205 ends the reporting period. Ending the reporting period may mean using the period after the end of the reporting period for purposes other than reporting. For example, as shown in FIG. 9B, when the reporting period ends early, the subsequent period may be set as the communication period. By doing so, if the reporting period ends early, it is possible to secure a longer period for communication in a more appropriate channel according to the sensing result. When the reporting period ends, even if there are unsent sensing results, those unsent sensing results will not be sent. This is because there is no need to send sensing results after the reporting period ends. Also, the period after the end of the reporting period may be used, for example, as the period for channel change according to the integrated sensing information. In that case, in FIG. 9(a), compared to when the channel is changed within the communication period, it is possible to increase the time during which communication can be performed using a more appropriate channel. Note that communication may be performed between the access point AP and the wireless communication device during the reporting period of FIG. 9 as well. However, the communication is communication before control such as channel change according to the report is performed. Also, FIG. 9 shows the case where the sensing period and the report and communication period are provided separately, but the sensing period and the report and communication period may be provided in parallel. That is, sensing may be performed continuously.

As described above, even if the transmission timing of the sensing result is controlled so that the transmission timing of the sensing result becomes earlier as the appropriateness regarding the sensing result of the own device is lower, the appropriateness of the sensing result in the BSS as a whole If it is high, there may be no reports in the first half of the reporting period and reports concentrated in the second half. In that case, there is a problem that an unnecessary waiting time occurs, making it impossible to select a channel in a short period of time. Even if the appropriateness of the sensing result is high as a whole, by controlling the transmission timing and the end of the reporting period, for example, as shown in FIG. 9C, the transmission timing is controlled. The reporting period is shorter than in the situation without (Fig. 9(a)). However, the extent to which it is shortened is reduced (eg, the reporting period is longer than in FIG. 9(b)).

Therefore, as described above, the longer the non-report period, which is the period until the first sensing result is received from another wireless communication device 200, the longer the transmission time determination section 204 determines the end time (end time). Update the transmission time to be within the earlier reporting time window. That is, when the non-reporting period is long (that is, when the appropriateness of the sensing results observed in the BSS is high as a whole), the transmission timing determining unit 204 probabilistically advances the transmission timing of the sensing results. so that the send time is updated. Therefore, the transmission time determination unit 204 may update the end of the reporting time window as follows. However, the function F(x) is assumed to be an increasing function of the argument x. Therefore, the longer the non-reporting period, the earlier the reporting time window (RTW) ends (closer to the start of the reporting period). Also, when the non-reporting period is 0 (at the start of the reporting period), F(0)=0 may be used.
End of RTW (appropriateness, non-reporting period) = appropriateness x RTW ₀ + base-F (non-reporting period)

Note that the end of the reporting time window may be shortened by a predetermined period each time the non-reporting period increases by the unit period. In that case, when the non-reporting period reaches N×unit period, the end of the reporting time window may be updated as follows. Note that N is an integer of 1 or more. Also, PE is a predetermined period. In the following formula, each time the non-reporting period increases by the unit period, the end of the reporting time window is shortened by the period PE. Although PE is a constant here, it does not have to be. For example, PE may be made smaller or larger as N becomes larger. That is, PE may be a decreasing or increasing function of N, for example.
End of RTW (relevance, N) = relevance x RTW ₀ + base-N x PE

Here, referring to FIG. 11, a method of updating the transmission time by shortening the end of the reporting time window by a predetermined period each time the non-reporting period increases by a unit period will be described. In the following description, for the sake of convenience, base in the above equation may be set to 0.

First, assume that a reporting time window is set at the beginning of the reporting period, as shown in FIG. 11A. It is assumed that the channel utilization rate of STA1 is 20% and the channel utilization rate of STA2 is 10%. Therefore, the reporting time window of STA1 is shorter than the reporting time window of STA2. Note that the reporting time window of the information gathering apparatus (AP) 300 has a length (default reporting time window length ). Transmission point determination section 204 randomly determines a transmission point in each reporting time window. In this case, the transmission instant will be any instant between that instant (time 0) and the end of the reporting time window. Note that the determined transmission time is not shown.

Next, assume that the sensing result is not transmitted from the start of the reporting period until time T1 (=ΔT). It is assumed that ΔT is the unit period. Then, STA1 and STA2 each shorten the end of the reporting time window by PE (N=1 in the above equation), as shown in FIG. 11B. The transmission time determination unit 204 updates the transmission time by randomly (eg uniformly randomly) determining the transmission time again in the shortened reporting time window. In this case, the transmission instant will be any instant between that instant (time T1) and the end of the reporting time window shortened by PE. Note that the determined transmission time is not shown.

After that, it is assumed that the next unit period has passed and the sensing result has not been transmitted even after the time T2 (=2×ΔT) has passed since the start of the reporting period. Then, STA1 and STA2 further shorten the end of the reporting time window by PE respectively (N=2 in the above equation), as shown in FIG. 11C. The transmission time determination unit 204 updates the transmission time by randomly determining the transmission time again in the shortened reporting time window. It is assumed that the transmission time determined by STA1 is the time indicated by the black circle in the figure.

When the updated transmission time comes, STA1 transmits the sensing result. The sensing result is received by the information gathering device (AP) 300 and STA2, and the non-reporting period ends. Then, since the non-report period includes two unit periods ΔT, acquisition section 302 substitutes the appropriateness of the sensing result received from STA1 and the length of the non-report period (N=2) into the above equation. By doing so, the reporting end time (T11), which is the end of the reporting time window, can be obtained. In this case, the report end time is the shortest report end time. Further, when another sensing result is received after that, the report end time is obtained accordingly, and the shortest report end time is specified. If there is no transmission of a sensing result with a lower appropriateness than the appropriateness of the sensing result transmitted from STA1 by the shortest reporting end time T11, information collection device 300 reports to each wireless communication device 200 at time T11. A notice of the end of the period will be sent and the reporting period will be closed. In this way, even when the appropriateness of the sensing result is high, the communication period can be started earlier by moving up the end of the reporting period as shown in FIG. 9(d). become.

It is also assumed that the sensing result transmitted from STA1 is not received by another wireless communication device 200 (here, STA2). In that case, STA2 will advance the expiration of the reporting time window further, as shown in FIG. 11D. On the other hand, since information gathering device 300 can receive sensing results transmitted from each wireless communication device 200 in the BSS, acquisition unit 302 of information gathering device 300 uses an accurate non-reporting period to obtain a report. Get the end time. Therefore, even if the situation shown in FIG. 11D occurs, the notification of the end of the reporting period will be transmitted at an appropriate time, and the necessary transmission of sensing results from wireless communication device 200 has not been completed. At that point, you can avoid situations where the reporting period ends.

Also, as described above, every time the non-reporting period increases by the unit period ΔT, the end of the reporting time window is advanced by a predetermined period PE, and the time from the current point to the end of the reporting time window is is less than the predetermined period PE, the transmission point determination unit 204 may not update the transmission point. This is because if the transmission time is updated in such a situation, the end of the updated reporting time window will be in the past.

In this way, when the end of the reporting time window after updating is in the past, if the transmission time is not updated, the end of the reporting time window corresponding to a sensing result with a low degree of appropriateness will be delayed. , could be later than the end of the reporting time window corresponding to the more relevant sensing results. To reduce such a possibility, it is preferable to set the predetermined period PE to a short value so that the end of the reporting time window is brought forward by small increments. In addition, as another method for avoiding such a situation, the reporting time window may have a length corresponding to the degree of appropriateness, and may be an integral multiple of the predetermined period PE. In this case, the length of the first reporting time window may be calculated as follows. Note that floor(x) is a floor function that returns the largest integer equal to or less than the argument x, and M is an integer equal to or greater than 2 and is determined in advance.
RTW (appropriateness)=floor (appropriateness×M)/M×RTW ₀ +base

By doing so, it is considered that the length of the reporting time window of M stages is obtained using the appropriateness converted to M stages of 0, 1/M, . . . , (M−1)/M. be able to. Further, by setting the predetermined period PE to PE=RTW ₀ /M, even if the end of the reporting time window is updated every unit time, the end will be aligned for each RTW ₀ /M. It becomes possible to avoid the end of the reporting time window corresponding to the low degree of sensing result being later than the end of the reporting time window corresponding to the more appropriate sensing result. The same thing may be realized by using a ceiling function instead of the floor function, or by using other functions.

Also, the case where the updated transmission time point is randomly determined in the updated reporting time window has been mainly described, but this need not be the case. The transmission time before the update may be used to calculate the transmission time after the update. FIG. 12 is a diagram for explaining the calculation process. In FIG. 12, the reporting time window used to determine the transmission time before updating (hereinafter sometimes referred to as the “reporting time window at the initial transmission time”) is the window from time 0 to time RTW _COR . and Suppose the transmission time TP is determined in that reporting time window. Also, if there are N×ΔT unreported periods, which are N unit periods (ΔT), then the updated transmission point in time TN (=N×ΔT) is from time TN to time (RTW _COR −N× PE) (hereinafter sometimes referred to as "reporting time window at time TN"). The reporting time TP _new in the reporting time window of time TN may be calculated using the transmission time before updating (here, the first transmission time TP) as in the following equation.

where the ratio of the length of time TN to time TP to the length of time TN to time RTW _COR in the reporting time window at the time of the first transmission is the length of time TN to time TP to the length of time TN reporting time window The reporting time TP _new will be calculated to be equal to the ratio of the lengths to TP _new . Therefore, in this case, the reporting time _TPnew will not be later than the initial transmission time TP, and the transmission timing will be brought forward each time the transmission time is updated.

Here, a case is shown in which the transmission time TP _new at time TN is calculated using the transmission time TP at time 0, but this need not be the case. For example, the transmission point in time TN may be calculated using the transmission point in time T(N−1) (=(N−1)×ΔT).

Alternatively, the reporting time point TP _new may be calculated by another calculation formula. The following formula is an example. where the ratio of the length of time 0 to time TP to the length of the reporting time window at the time of the first transmission is the ratio of the length of time TN to time TP _new to the length of the reporting time window of time TN. The reporting time TP _new will be calculated to be equal to the ratio.

Thus, when the updated transmission time point is calculated using the previous transmission time point, the transmission time determination unit 204 does not need to calculate the end of the updated reporting time window. However, even in such a case, the updated transmission time point calculated by the transmission time determination unit 204 using the above equation is between the time of calculation and the end of the updated reporting time window. It's time. Therefore, as a result, the transmission time determination unit 204 has updated the transmission time to be within the updated reporting time window at the end. Moreover, even in the case of calculating the post-update transmission time using the pre-update transmission time, the initial transmission time is randomly determined as described above. Therefore, the updated transmission time determined directly or indirectly using the randomly determined initial transmission time can also be considered to be the randomly determined transmission time in the updated reporting time window. can.

Here, the integrated sensing information transmitted from the access point AP1 (information collection device) to each wireless communication device will be described. Since the access point AP1 holds the sensing result with the lowest appropriateness, for example, when the sensing result is reported as shown in FIG. The integrated sensing information “60%” may be transmitted to each wireless communication device STA11-STA15. The transmission may be performed using a control channel, which is a predetermined radio channel. Further, when the sensing results are transmitted for a plurality of wireless channels, the integrated sensing information is selected by the access point AP1 according to the sensing results transmitted from the plurality of wireless communication devices. It may be information indicating one or more radio channels used in . Specifically, for wireless channels ch1, ch2, ch3, ch4, and ch5, the maximum channel utilization indicated by the sensing result transmitted from each wireless communication device is 60%, 30%, 40%, and 50%, respectively. , 20%, the access point AP1 selects three channels in descending order of channel utilization rate (in descending order of appropriateness), and performs integrated sensing indicating the selected radio channels ch2, ch3, and ch5. Information may be sent to each wireless communication device STA. Then, each wireless communication device STA may perform wireless communication using the wireless channels ch2, ch3, and ch5. Note that the number of radio channels to be selected may be determined in advance, or may be determined according to sensing results. In the latter case, for example, radio channels within a predetermined number may be selected from among the radio channels whose adequacy is equal to or greater than a predetermined threshold. Specifically, when the threshold is set to a channel utilization rate of 30% and the predetermined number is "3", ch2 and ch5 are indicated from the access point AP1 in the above example. Integrated sensing information may be sent to each wireless communication device STA.

Next, the operation of radio communication apparatus 200 will be described using the flowchart of FIG. FIG. 5 is a diagram illustrating a flow in which wireless communication apparatus 200 determines transmission or non-transmission of sensing results by autonomous distributed cooperative sensing.

(Step S101) The channel usage status observation unit 201 performs sensing by observing the usage status of a plurality of target wireless channels with which wireless communication may be performed. Note that the start timing of the first sensing period in a certain cell may be designated by the access point AP (information collection device 300).

(Step S102) Channel usage observation section 201 determines whether or not to end sensing. If the sensing is to end, the process proceeds to step S103; otherwise, the process returns to step S101. In this way, sensing continues until the sensing period ends.

(Step S103) When the sensing period ends, the sensing result transmission unit 202 acquires the sensing result according to the observation result. Here, it is assumed that the sensing result is the channel utilization rate.

(Step S104) The transmission point-in-time determining unit 204 generates a report time window whose size decreases as the appropriateness of the sensing result of its own apparatus decreases.

(Step S105) The transmission time determination unit 204 randomly determines the first transmission time (transmission timing) for transmitting the sensing result in the reporting time window generated in step S104.

(Step S106) The transmission control unit 205 determines whether or not it is time to transmit the sensing results determined in step S105 or updated in step S110. Then, if the transmission time has come, the process proceeds to step S107, and if not, the process proceeds to step S108.

(Step S107) The sensing result transmission unit 202 transmits the sensing result to the access point AP (information collection device 300).

(Step S108) The sensing result receiving unit 203 determines whether or not the notification of the end of the reporting period has been received. Then, when the notification of the end of the reporting period is received, the transmission control section 205 ends the reporting period. Thus, the sensing result reporting process is terminated. On the other hand, if the notification of the end of the reporting period has not been received, the process proceeds to step S109.

(Step S109) The transmission time determination unit 204 determines whether or not to update the transmission time. If the transmission time point is to be updated, the process proceeds to step S110; otherwise, the process proceeds to step S111. For example, the transmission time determination unit 204 determines that the first sensing result transmitted from another wireless communication device 200 has not been received by the sensing result reception unit 203 of the own device, and the previous transmission time is updated. It may be determined that the transmission time point is to be updated when a predetermined period (the above-mentioned unit period) has passed from (the start time of the reporting period if the update has not been performed).

(Step S110) The transmission time determination unit 204 updates the transmission time. It should be noted that the transmission time after updating is the transmission time within the reporting time window, which ends earlier as the non-reporting period becomes longer. Then, the process returns to step S106.

(Step S<b>111 ) Sensing result receiving unit 203 determines whether sensing results transmitted from other wireless communication devices 200 have been received. Then, when the sensing result transmitted from another wireless communication device 200 is received, the process proceeds to step S112, otherwise, the process returns to step S106. Note that after receiving the first sensing result from another wireless communication device 200, the update of the transmission time in step S110 is no longer performed.

(Step S112) The transmission control unit 205 determines whether the sensing result transmitted from the other wireless communication device 200 is worse than the sensing result of its own device, that is, whether the appropriateness is low. Then, if the sensing result transmitted from another wireless communication device 200 has a lower degree of appropriateness, the process proceeds to step S113; otherwise, the process returns to step S106.

(Step S<b>113 ) The transmission control unit 205 cancels transmission of the sensing result by the sensing result transmission unit 202 . As a result, the sensing result is not transmitted from the own device during the reporting period. Then, the process proceeds to step S114.

(Step S114) The sensing result receiving unit 203 determines whether or not the notification of the end of the reporting period has been received. Then, the transmission control unit 205 ends the reporting period if the notification of the end of the reporting period is received, otherwise repeats the process of step S114 until the notification of the end of the reporting period is received. Thus, the sensing result reporting process is terminated. After the reporting period ends, for example, during the communication period shown in FIG. 9D, wireless communication can be performed using the channel selected according to the collected sensing results. In each wireless communication device 200, when the sensing result is transmitted or when the transmission of the sensing result is canceled, the reporting period is terminated without waiting for reception of the notification of the end of the reporting period. good.

Here, when the start points of the reporting periods are the same for a plurality of wireless communication devices 200, the sensing results are transmitted as described above, thereby enabling the comparison of the sensing results of the own device and the other devices. Processing will be reset every reporting period. For example, for a plurality of wireless communication devices 200, when the timing of starting sensing of the target channel in step S101 is synchronized and the sensing period until the end of sensing is the same, the plurality of wireless communication devices 200 The starting points of the reporting periods of the communication devices 200 will match. In order to synchronize the reporting periods in the plurality of wireless communication apparatuses 200 and information collecting apparatuses 300, the information collecting apparatus (access point AP) 300 may transmit, for example, a start beacon indicating the start of the reporting period.

Note that the processing of the flowchart of FIG. 5 is repeatedly executed in each wireless communication device 200 . Also, the determination process in step S112 may be performed for each of a plurality of wireless channels. Then, for example, when the sensing result of the own device is lower in appropriateness than the sensing result of the other device for any wireless channel, the process may return to step S106. When the process returns to step S106 in this way, only the radio channel for which the sensing result of the own device has been determined to be lower in appropriateness than the sensing result of the other device is subjected to the determination of steps S111 and S112 thereafter. may be performed. Further, in step S107, the sensing results of all wireless channels may be transmitted, or in step S112, it is determined that the sensing results of other devices are less appropriate than the sensing results of the self device. Only sensing results corresponding to wireless channels other than wireless channels may be transmitted. Further, when the periodic sensing and the periodic transmission of the sensing result are executed in parallel, the acquisition processing of the sensing result in steps S101 to S103 and the transmission or transmission of the sensing result in steps S104 to S114 are performed. The cancellation process may be executed in parallel.

Next, the operation of the information collection device 300 will be described using the flowchart of FIG. FIG. 6 is a diagram for explaining a flow in which the information collection device 300, which is the access point AP, notifies the end of the reporting period.

(Step S201) The information collection device 300 determines whether the reporting period has started. If the reporting period has started, the process proceeds to step S202; otherwise, the process of step S201 is repeated until the reporting period starts. For example, when the information collection device 300 notifies each wireless communication device 200 of the start timing of the sensing period, the information collection device 300 determines that the reporting period has started when the length of the sensing period has elapsed from the start timing. may

(Step S202) The receiving unit 301 determines whether or not the sensing result transmitted from the wireless communication device 200 has been received. If the sensing result has been received, the process proceeds to step S203; otherwise, the process proceeds to step S207.

(Step S203) The receiving unit 301 determines whether the sensing result received in step S202 is the sensing result received for the first time in the reporting period. That is, the receiving unit 301 determines whether or not the sensing result is received for the first time in the reporting period. If it is the first reception, the process proceeds to step S204; otherwise, the process proceeds to step S205.

(Step S204) The acquisition unit 302 acquires the length of the non-reporting period. Acquisition of the length of the non-report period may be acquisition of how many unit periods the non-report period corresponds to. In that case, for example, the acquisition unit 302 may acquire a quotient value obtained by dividing the length of the non-report period by the unit period.

(Step S205) The acquisition unit 302 calculates the reporting end time using the non-report period acquired in step S204 and the appropriateness of the sensing result received in step S202.

(Step S206) The specifying unit 303 updates the shortest report end time according to the report end time calculated in step S205. That is, when there is a report end time acquired so far, the specifying unit 303 determines the shortest report end time as , the shortest report end time may be updated so as to be the report end time of the earlier end. Further, when there is no report end time acquired so far, the specifying unit 303 may set the shortest report end time to the newly acquired report end time. Then, the process returns to step S202.

(Step S207) The transmission unit 305 determines whether or not the shortest reporting end time has arrived. Then, if the shortest reporting end time has come, the process proceeds to step S208, and if not, the process returns to step S202. Note that if the sensing result has not been received since the start of the reporting period and, therefore, the calculation of the reporting end time and the specification of the shortest reporting end time have not been performed, the transmitting unit 305 does not specify the shortest reporting end time. It may be determined that has not arrived.

(Step S208) The transmitting unit 305 notifies the end of the reporting period by transmitting the integrated sensing information generated by the generating unit 304 to the plurality of wireless communication devices 200 . Then, the process returns to step S201. Note that the generation unit 304 may update the integrated sensing information each time a sensing result is received, or may generate the integrated sensing information after the reporting period ends. Further, when the transmission of the integrated sensing information and the notification of the end of the reporting period are separate, the transmission unit 305 transmits the integrated sensing information to each wireless communication device after the notification of the end of the reporting period. good too.

As described above, among the sensing results observed by each wireless communication device 200, which is a sensing terminal, the maximum or minimum value is transmitted to the information collection device 300, and cooperative sensing can be executed with low overhead. It is possible. Moreover, since the transmission timing of the sensing result is also controlled, it is possible to reduce unnecessary transmissions before useful information is transmitted. Also, if one transmission timing is determined according to the appropriateness of the sensing result, there is a risk of collision occurring in the transmission of the sensing results when the appropriateness of the sensing results in the plurality of wireless communication devices 200 is the same. However, randomly determining the transmission timing in the reporting time window makes it possible to avoid such collisions. Moreover, in wireless communication apparatus 200 and information collecting apparatus 300 according to the present embodiment, unnecessary transmission of sensing results can be avoided by ending the reporting period early. For example, in FIG. 7, transmission of sensing results from the STA 13 can be prevented. As a result, use of unnecessary radio resources can be reduced. In addition, since each wireless communication device 200 can end the reporting period in response to the notification of the end of the reporting period from the information collecting device 300, it is possible to perform channel selection and the like during the period that was conventionally the reporting period. It will be possible to make effective use of the period. Furthermore, even if the pertinence of the sensing results in the BSS is high and the timing of sending the sensing results may be delayed in the reporting period, the longer the non-reporting period, the earlier the termination in the reporting time window. The reporting period can be shortened by performing forward control of the transmission time so that it is the transmission time. As a result, wireless communication using the channel selected according to the sensing result can be started earlier. In addition, since the information collection device 300 notifies the end of the reporting period when the shortest reporting end time has passed, it is possible to receive the sensing result with the lowest appropriateness in the BSS, even if the reporting period is shortened. , channel selection, etc. are not affected. In addition, by using the results of cooperative sensing, it is possible to flexibly select channels of multiple frequency bands or use them simultaneously, so that radio resources can be utilized without waste and frequency utilization efficiency can be improved.

Next, it will be explained that, in selective reporting, the transmission timing is more likely to be earlier if the transmission timing is controlled as in the present embodiment compared to the case where the transmission timing is not controlled. do. It should be noted that no consideration is given here to forward control at the time of transmission.

Here, it is assumed that wireless communication devices x and y that perform sensing exist within a range in which wireless communication can be performed with each other. First, wireless communication device x shall determine the transmission instant in a reporting time window (0, R _a ) sized according to the COR, and the other wireless communication device y shall determine the default reporting time window (0, R _b ) shall determine the time of transmission.

Also, to simplify the transmission time points, the transmission time points are discrete numbers starting from 1, and R _a and R _b are integers greater than one. Then, the probability P _CORxEy that the transmission time of the wireless communication device x is earlier than that of the wireless communication device y is given by the following equation.

Next, the probability P _UNIxEy that wireless communication device x will have an earlier transmission time than wireless communication device y when wireless communication device x also determines the transmission time in the default reporting time window (0, R _b ) is , becomes

Then, P _DiffxEy , which is the difference between the two, is given by the following equation.

Here, since R _b ≧R _a ≧0, P _DiffxEy is a value between [0, 1/2]. Thus, since P _DiffxEy ≧0, the case of control of transmission instants, i.e., the size of the reporting time according to the COR, is higher than that of no transmission instant control, i.e., using the default reporting time window. It can be seen that the probability of earlier transmission timing is greater or the same when using a window. Therefore, it has been proved that the transmission time is not probabilistically delayed by controlling the time of transmission than it would be without the time of transmission. In addition, if the transmission timing is brought forward, the transmission timing will not be delayed as compared to the case where it is not. Therefore, it can be seen that when the transmission time point control and the transmission time forward control are performed, the transmission time point is stochastically not delayed as compared to the case where it is not.

In the above description, the case where cooperative sensing is performed for one wireless channel has been described, but similar cooperative sensing may be performed for a plurality of wireless channels. In that case, for example, the transmission control unit 205 may perform the above-described control regarding transmission of sensing results for each of a plurality of wireless channels. Assuming that radio channels ch1, ch2 and ch3 are assumed as a plurality of radio channels, it is assumed that the sensing results corresponding to the observations by the radio communication devices STA11 to STA15 shown in FIG. 7 are as follows. It is assumed that channel utilization rates, which are sensing results, correspond to ch1, ch2, and ch3 in order from the left.
(ch1, ch2, ch3)
STA11: (60%, 40%, 20%)
STA12: (40%, 30%, 10%)
STA13: (30%, 10%, 10%)
STA14: (20%, 20%, 40%)
STA15: (10%, 20%, 20%)

In this case, for ch1, for example, the transmission time points are determined in order of STA11, STA12, STA13, STA14, and STA15, and for ch2, for example, the order is STA11, STA12, STA14, STA15, and STA13. For ch3, for example, the transmission times are determined so that the order is STA14, STA11, STA15, STA12, and STA13. Further, referring to FIG. 9, for example, sensing of wireless channel ch1 is performed in the first sensing period, sensing of wireless channel ch2 is performed in the next sensing period, and sensing of wireless channel ch3 is performed in the next sensing period. When sensing is performed, first, the wireless communication device STA11 transmits the sensing result of ch1 in the first reporting period. After that, the wireless communication device STA12 does not perform transmission because the appropriateness of ch1 is higher than the already transmitted sensing result of ch1. After that, if the end of the reporting period is notified, the wireless communication devices STA13 to STA15 end the reporting period and do not transmit sensing results. In the next reporting period, the wireless communication device STA11 transmits the sensing result of ch2. After that, the wireless communication device STA12 does not perform transmission because the appropriateness of ch2 is higher than the already transmitted sensing result of ch2. After that, if the end of the reporting period is notified, the wireless communication devices STA13 to STA15 end the reporting period and do not transmit sensing results. In the next reporting period, the sensing result of ch3 is transmitted from wireless communication device STA14. After that, if the end of the reporting period is notified, the wireless communication devices STA11 to STA13 and STA15 will end the reporting period and will not transmit the sensing results. In this way, even when sensing results are transmitted for each of a plurality of wireless channels, the number of transmissions of sensing results (report number) can be suppressed.

Note that when performing cooperative sensing on a plurality of wireless channels, it is not necessary to control transmission of sensing results for each wireless channel. You may make it collectively perform about several radio channels. In that case, the transmission control unit 205 may use, for example, a representative value among the sensing results of a plurality of wireless channels to determine the transmission time point and control whether or not to transmit. The total value of the sensing results may be used to determine the timing of transmission and control whether or not to transmit. The representative value may be, for example, a value with the lowest degree of appropriateness, an average value, or any other representative value. Here, a specific description will be given of a case where transmission control is performed using a sensing result with the lowest degree of appropriateness among sensing results of a plurality of radio channels. In the above examples of STA11 to STA15, the sensing results with the lowest appropriateness are as follows.
STA11: 60%
STA12: 40%
STA13: 30%
STA14: 40%
STA15: 20%

Therefore, in this case, for example, the transmission time points are determined in order of STA11, STA12, STA14, STA13, and STA15, and the wireless communication devices STA11 and STA14 transmit sensing results. Note that if the reporting period ends before the transmission of the wireless communication device STA14, the transmission of the sensing results after the wireless communication device STA14 will not be performed. In this case, since determination is collectively made for a plurality of wireless channels, it is preferable to transmit sensing results for each of the plurality of wireless channels when transmitting sensing results.

Next, a case where transmission control is performed using a total value of sensing results of a plurality of radio channels among sensing results of a plurality of radio channels will be specifically described. In the above example of STA11 to STA15, the total value of sensing results (channel utilization rate) for each wireless channel is as follows.
STA11: 120%
STA12: 80%
STA13: 50%
STA14: 80%
STA15: 50%

Therefore, in this case, for example, the transmission time points are determined in order of STA11, STA12, STA14, STA13, and STA15, and the wireless communication devices STA11 and STA14 transmit sensing results. Note that if the reporting period ends before the radio communication device STA14 transmits, the sensing result will not be transmitted from the radio communication device STA14. In this case, since determination is collectively made for a plurality of wireless channels, it is preferable to transmit sensing results for each of the plurality of wireless channels when transmitting sensing results.

Note that, for example, when the wireless communication device can perform sensing on a plurality of wireless channels in a certain sensing period, it controls the transmission of the sensing result using the representative value, and transmits one wireless channel in a certain sensing period. When sensing can be performed only on channels, control regarding transmission of sensing results may be performed for each wireless channel.

Also, in the above description, the wireless communication devices STA11 to STA15 acquire sensing results for each of the three wireless channels, but this need not be the case. At least one of the plurality of wireless communication devices may not acquire sensing results for some wireless channels. Even in such a case, by transmitting sensing results from a plurality of wireless communication devices to the access point AP, the access point AP can receive the sensing results for each of the plurality of wireless channels. preferred.

Next, communication using a plurality of radio channels separated from each other will be described.
FIG. 13 is a conceptual diagram for explaining radio channels in a plurality of mutually separated frequency bands.

In FIG. 13, as an example, the horizontal axis represents frequency, and the above-described 920 MHz band, 2.4 GHz band, and 5 GHz band are shown as unlicensed bands. Each frequency band includes multiple radio channels that are selectively used in communication.

Here, with regard to the wireless communication device of the present embodiment, which will be described later, generally, a plurality of frequency bands separated from each other are used, and communications are performed concurrently and in parallel at synchronized timings in the same wireless system or different wireless systems. It is possible to apply to a transmitting device that performs

FIG. 14 is a conceptual diagram for explaining the configuration of the radio communication system according to this embodiment.

Referring to FIG. 14, on the premise that the transmitting side uses three frequency bands of 920 MHz band, 2.4 GHz band, and 5 GHz band, one radio channel is used in each band. configure.

Although a plurality of channels may be used for each frequency band, the following description assumes that one channel is used for each frequency band.

In this embodiment, radio access control having the following features is performed.

That is, first, the transmitting side senses and observes the utilization status of multiple frequency bands (such as the availability status of each wireless channel) by a method to be described later.

Subsequently, the transmitting side simultaneously transmits radio packets (frames) in one or more unused frequency bands/radio channels at a certain timing. At this time, the transmission data is mapped to a plurality of bands and transmitted.

On the other hand, the receiving side collectively receives multiple bands and integrates the data.

In transmission and reception, if such a configuration is adopted, transmission opportunities can be secured even if there is unevenness in congestion between bands, so improvement in frequency utilization efficiency and reduction in transmission delay can be expected. No problem.

FIG. 15 is a diagram for explaining a specific example for mapping transmission data to a plurality of bands, transmitting the data, and collectively receiving and integrating the data on the receiving side.

As shown in FIG. 15, the series of transmission data is divided by the number of symbols proportional to the transmission rate Ri of each band used and assigned to each band by serial/parallel conversion.

For example, if (5 GHz band transmission rate: 2.4 GHz band transmission rate: 920 MHz band transmission rate)=(R1:R2:R3)=(3:2:1), the transmission data sequence is divided every 6 symbols, 3 symbols, 2 symbols, and 1 symbol are assigned to the 5 GHz band (ch1), 2.4 GHz band (ch2), and 920 MHz band (ch3). In addition, when the transmission sequence is divided and assigned, it is not limited to such a case, and more generally, when m frequency bands are used, the ratio of the transmission rates of the frequency bands is set to (R1:R2 : ...: Rm) (the ratio is expressed irreducibly), the transmission sequence is divided into (R1 + R2 + ... + Rm) × n (m, n: natural number) symbols, and each channel has ( R1×n) symbols, (R2×n) symbols, . . . , (Rm×n) symbols may be assigned.

After such allocation, a physical header is attached to the transmission symbols for each band to form packets, and these packets are transmitted simultaneously and in parallel at the same timing.

The number of symbols assigned to each band on the transmitting side is stored as information in this physical header or preset as control information before transmission.

The receiving side uses the physical header on each band to perform synchronization and demodulation processing. Each demodulated series is combined by parallel/serial conversion in the reverse process of the transmission side, and the frame is decoded.

[Structure of transmitter]
FIG. 16 is a functional block diagram for explaining the configuration of transmitting apparatus 1000 of this embodiment.

Referring to FIG. 16, transmitting apparatus 1000 performs error correction coding section 1110 for performing error correction coding processing on a sequence of transmission data, and interleave processing on data after error correction coding. An interleaving unit 1112 to perform, a serial/parallel conversion (hereinafter referred to as S/P conversion) unit 1010 for performing the process of assigning to each frequency band as described in FIG. Radio frame generators 1020.1 to 1020.3 for performing digital processing for forming radio frames (packets) for communication in a predetermined radio communication method, such as mapping processing and addition of physical headers, for each frequency band , digital-to-analog conversion processing and modulation processing to a predetermined modulation method (for example, quadrature modulation for a predetermined multilevel modulation method) are performed on the digital signals from radio frame generation units 1020.1 to 1020.3, respectively. high-frequency processing units (RF units) 1040.1 to 1040.3 for executing processing), up-conversion processing, power amplification processing, etc.; .1 to 1050.3. The operations of RF sections 1040.1 to 1040.3 are controlled based on a clock from local oscillator 1030 provided in common to them.

Furthermore, transmitting apparatus 1000 includes channel usage status observing section 201 that observes the usage status (such as availability of each wireless channel) of each frequency band (one or more wireless channels in each frequency band), and channel usage status Based on the observation by observation section 201, channel usage prediction section 1070 predicts the channel usage at a predetermined timing; an access control unit 1080 that controls the transmission timing in .3 so that radio packets are simultaneously transmitted in unused frequency bands and radio channels for a predetermined period at the same controlled transmission timing; a sensing result transmitting unit 202 for transmitting sensing results according to the usage status to the information collecting device; a sensing result receiving unit 203 for receiving sensing results transmitted from other wireless communication devices to the information collecting device; The sensing result according to the observation by the device (observation by the channel usage status observation unit 201) is transmitted from another wireless communication device, and the wireless channel is used more than the sensing result received by the sensing result reception unit 203. and a transmission control unit 205 that controls the sensing result transmission unit 202 so as not to transmit the sensing result of its own device when the appropriateness indicating that it is suitable for the device is high. Further, the transmission control unit 205 transmits the sensing result at the transmission time determined probabilistically such that the lower the appropriateness of the sensing result of the device itself, the earlier the transmission time of the sensing result. Also, the transmission time is updated to become earlier probabilistically as the non-reporting period becomes longer. In FIG. 16, the transmission point determination unit 204 that determines the transmission point is omitted due to space limitations.

Here, the configuration is such that the channel usage status observation section 201 executes the above-described carrier sensing and channel sensing.

Here, the access control unit 1080 selects and uses a channel that is found to be usable according to the result of carrier sensing of the candidate target band at the time of transmission, and uses an unused channel at the same controlled transmission timing. Radio packets are transmitted simultaneously in frequency bands and radio channels. Also, the access control unit 1080 controls the transmission timing based on the integrated sensing information. Based on the integrated sensing information means transmitting wireless packets in one or more wireless channels determined using the integrated sensing information or in one or more wireless channels indicated by the integrated sensing information. is. In the former case, for example, the wireless communication device may determine one or more wireless channels to be used for wireless communication based on integrated sensing information.

A detailed example of the operation of channel usage prediction section 1070 will be described later. However, the access control section 1080 may be configured to control the transmission timing by directly using the observation result of the channel usage status observation section 201 so as to use the frequency band determined to be available at the present time.

As described with reference to FIG. 15, the transmitting apparatus 1000 configured as described above maps data to a plurality of bands and transmits the data, and the receiving side collectively receives the plurality of bands and integrates the data.

Sensing result transmitting section 202 inputs the sensing result to be transmitted to error correction encoding section 1110 as data to be transmitted. Then, modulation and the like are performed as described above, and the sensing result is transmitted to the access point AP, which is the information collecting device. In addition, the transmission may be transmitted by one predetermined frequency band. For example, if control signals and the like are to be transmitted and received between the access point AP and the terminal using a 2.4 GHz band control channel, sensing results are transmitted only in the 2.4 GHz band. may Note that FIG. 16 shows a case where the sensing result transmission unit 202 does not include a subsequent configuration related to transmission, for example, an error correction coding unit 1110, a radio frame generation unit, an RF unit, etc., but the sensing result transmission unit 202 may contain some or all of the subsequent configuration for such transmission.

Sensing result reception unit 203 receives sensing results transmitted from other wireless communication devices, integrated sensing information transmitted from information collection device 300, and notification of the end of the reporting period from error correction unit 4040, which will be described later. good. Therefore, the wireless communication device of the present invention may also have the configuration of a receiving device, which will be described later. A sensing result transmitted from another wireless communication device is a sensing result according to observation by the wireless communication device that is the transmission source. It should be noted that the sensing result receiving unit 203 also shows a case where the preceding configuration related to reception, for example, does not include an RF unit, a digital signal processing unit 2800, an error correction unit 4040, etc., which will be described later, but the sensing result receiving unit 203 , may have some or all of the preceding configuration for such reception. Moreover, when the sensing result is transmitted by one predetermined frequency band, the sensing result is also received by that one frequency band.

In this way, when radio communication apparatus 200 performs communication using a plurality of radio channels on which random access control is performed in each of a plurality of frequency bands separated from each other, transmission apparatus 1000 described above or It may have a configuration similar to that of the receiving apparatus 2000. Also, when the information collection device 300 performs communication using a plurality of radio channels on which random access control is performed in each of a plurality of frequency bands separated from each other, the transmission device 1000 described above and the reception device described later It may have the same configuration as the device 2000 . In that case, the transmitting device 1000 may have a receiving section 301, an acquiring section 302, etc. instead of the sensing result transmitting section 202, the sensing result receiving section 203, and the like.

[Detailed Configuration of Wireless Communication Device]
FIG. 17 is a functional block diagram for explaining an example of a more detailed configuration of transmitting apparatus 1000. As shown in FIG.

The functional block diagram shown in FIG. 17 shows, as an example, the configuration of a transmitting device that complies with a wireless communication scheme similar to wireless communication standard 802.11a.

That is, although the wireless communication standard 802.11a is a wireless LAN communication method in the 5 GHz band, in FIG. shall use a transmitter that complies with

Therefore, in each frequency band, the configuration of the preamble portion of a packet, etc. shall be common to a plurality of frequency bands.

However, it is not essential that the wireless communication methods of each frequency band have the same configuration, and even if the wireless communication method (signal format, symbol length, subcarrier interval, etc.) differs for each frequency band, good. In this case, at least a single transmission sequence is divided into each band and transmitted simultaneously. (preamble length, etc.) may be different for multiple frequency bands.

FIG. 17 exemplarily shows a configuration related to transmission in the 5 GHz band. Since a wireless communication system similar to the wireless communication standard 802.11a is assumed, signals to be transmitted shall be OFDM (orthogonal frequency division multiplex) modulated.

Referring to FIG. 17, radio frame generation section 1020.3 receives transmission data distributed from S/P conversion section 1010, and performs mapping section 1122 for performing mapping processing and inverse Fourier transform processing. an IFFT section 1130 for adding a guard interval portion; a GI adding section 1140 for adding a guard interval portion; As shown in FIG. 17, radio frame generators 1020.1 to 1020.3 can also be called baseband processors. Further, since digital signal processing is performed in S/P conversion section 1010 and radio frame generation sections 1020.1 to 1020.3, they are collectively referred to as digital signal processing sections.

High-frequency processing section 1040.3 includes quadrature modulator 1210 for modulating the signal from DAC 1150 into a predetermined multilevel modulated signal, upconverter 1220 for upconverting the output of quadrature modulator 1210, and the output of upconverter 1220. and a power amplifier 1230 for power amplifying and transmitting from antenna 1050.3.

As a result, RF section 1040.3 converts the baseband OFDM signal to a carrierband OFDM signal.

Furthermore, high-frequency processing section 1040.3 includes clock frequency conversion section 1310 for converting the reference frequency signal from local oscillator 1030 into a reference clock signal of a corresponding frequency band, and clock frequency conversion section 1310 based on the reference clock from clock frequency conversion section 1310. a clock generation unit 1320 for generating a clock used for modulation processing in a quadrature demodulator 1210; and a clock generator 1340 that

That is, the reference frequency signal from local oscillator 1030 is used as a clock signal in such a conversion from baseband OFDM signal to carrier band OFDM signal. More generally, even if the wireless communication system is different, basically the reference frequency signal from the local oscillator 1030 is used as the clock signal in the conversion from the baseband signal to the carrierband signal.

As for the configuration and operation of channel usage status observation section 201, the same ones as those described in the cooperative sensing method described above can be used.

The channel usage status observation unit 201 observes the usage status of each frequency band (for example, the availability status and busy probability of each wireless channel, etc.) based on the sensing result of the own station and/or the sensing result of the assigned station, and predicts the channel usage status. The unit 1070 predicts the latest usage status of each frequency band, and the access control unit 1080 controls transmission timing accordingly.

[Configuration of Receiving Device]
The configuration of a receiving apparatus used in a radio communication system such as that described with reference to FIG. 15 will be described below.

FIG. 18 is a functional block diagram for explaining the configuration of receiving apparatus 2000 of this embodiment.

18, receiving apparatus 2000 includes antennas 2010.1 to 2010.3 for receiving signals in a plurality of frequency bands (920 MHz band, 2.4 GHz band, 5 GHz band), antenna 2010.1 2100.1 to 2100.3 for performing reception processing such as down-conversion processing, demodulation/decoding processing, etc. of the signals of . local oscillator 2020 that generates a reference frequency signal, which is a clock that serves as a reference for the operation of receiving sections 2100.1 to 2100.3, and each series of signals from receiving sections 2100.1 to 2100.3 are transmitted to the transmitting side. Inverse processing includes a parallel/serial converter 2700 for combining by parallel/serial conversion.

The integrated frame output from the parallel/serial (P/S) converter 2700 is passed to upper layers.

Receiving apparatus 2000 detects the frequency offset of local oscillator 2020 from the preamble signal of the received signal, generates a signal (oscillation frequency control signal) for controlling the oscillation frequency of local oscillator 2020, and performs carrier frequency synchronization processing. and also includes a synchronization processing unit 2600 that generates a signal (synchronization timing signal) for timing synchronization in digital signal processing from the received signal.

Receiving section 2100.1 receives a signal from antenna 2010.1 and performs low-noise amplification processing, down-conversion processing, demodulation processing for a predetermined modulation scheme (for example, quadrature demodulation processing for a predetermined multilevel modulation scheme), analog A high-frequency processing section (RF section) 2400.1 for executing digital conversion processing, etc., and a baseband for executing baseband processing such as demodulation/decoding processing on the digital signal from the RF section 2400.1 It includes a processing unit 2500.1.

Receiving section 2100.2 also includes high frequency processing section (RF section) 2400.2 and baseband processing section 2500.2 for performing similar processing for the corresponding frequency band. Receiving section 2100.3 also includes high frequency processing section (RF section) 2400.3 and baseband processing section 2500.3 for performing similar processing for the corresponding frequency band.

Baseband processing units 2500.1 to 2500.3 and parallel/serial (P/S) conversion unit 2700 are collectively referred to as digital signal processing unit 2800. FIG.

FIG. 19 is a functional block diagram for explaining an example of a more detailed configuration of receiver 2000 shown in FIG.

The functional block diagram shown in FIG. 19 also shows, as an example, the configuration of a receiving apparatus that complies with the wireless communication method similar to the wireless communication standard 802.11a.

Therefore, the configuration of the receiver corresponds to the configuration of the transmitter shown in FIG.

FIG. 19 also exemplifies the configuration of receiving section 2100.3 for the 5 GHz band as a representative.

Referring to FIG. 19, RF section 2400.3 of receiving section 2100.3 includes low noise amplifier 3010 for amplifying the received signal from antenna 2010.3, and low noise amplifier 3010 for frequency-converting the output of low noise amplifier 3010. a down converter 3020, an automatic gain controller 3030 for controlling the output of the down converter 3020 to have a predetermined amplitude, a quadrature demodulator 3040 for demodulating a predetermined multilevel modulated signal, and a quadrature demodulator and an analog-to-digital converter (ADC) 3050 for converting the I and Q component outputs of 3040 to digital signals, respectively.

RF section 2400.3 further includes clock frequency conversion section 3060 for converting the reference frequency signal from local oscillator 2020 into a reference clock signal of a corresponding frequency band, and based on the reference clock from clock frequency conversion section 3060, , a clock generation unit 3070 for generating a clock used for down-conversion processing in the down converter 3020, and a clock used for demodulation processing in the quadrature demodulator 3040 based on the reference clock from the clock frequency conversion unit 3060. and a clock generator 3080 .

Since a wireless communication system similar to the wireless communication standard 802.11a is assumed, the transmitted signal is OFDM (orthogonal frequency division multiplex) modulated. As a result, RF section 2400.3 converts the carrier band OFDM signal to a baseband OFDM signal.

The reference frequency signal from the local oscillator 2020 is then used for carrier frequency synchronization in such conversion from carrierband OFDM signals to baseband OFDM signals. More generally, even if the wireless communication system is different, basically the reference frequency signal from the local oscillator 2020 is used for carrier frequency synchronization in the conversion from the carrier band signal to the base band signal.

Baseband processing section 2500.3 includes GI removal section 4010 for receiving the signal from ADC 3050 and removing the guard interval portion, and fast Fourier transform for the signal from which the guard interval has been removed. An FFT section 4020 and a demapping section 4032 for performing demapping processing on the output of the FFT section 4020 are included.

After performing guard interval removal, FFT processing, and demapping processing in baseband processing units 2500.1 to 2500.3, P/S conversion unit 2700 combines signals of each frequency band for received data, Deinterleaving processing by deinterleaving section 4042 and error correction processing by error correcting section 4040 are executed.

Here, the synchronization timing signal output from synchronization processing section 2600 is used for symbol timing synchronization and the like for detecting the beginning of an OFDM symbol.

More generally, the synchronization timing signal output from synchronization processing section 2600 is basically used as a synchronization signal in baseband processing, even if the wireless communication system is different.

With the configuration described above, simultaneous multi-channel sensing can be efficiently performed when communicating in parallel in a plurality of frequency bands separated from each other. Also, each transmission data can be mapped to a plurality of frequency bands, and the transmission timing can be adjusted to perform data transmission.

(predictive sensing)
A configuration for predicting the probability of a channel being in a busy state or an idle state by using the channel utilization state prediction section 1070 based on channel utilization information obtained by cooperative sensing will be described below. First, as a premise for explaining the operations of channel usage status observation section 201 and channel usage status prediction section 1070, for explanation of terminology, a general method for avoiding transmission collisions from terminals in a wireless LAN will be briefly described. to explain.

In a wireless LAN, packets collide and efficient communication cannot be established unless they wait for each other to send. Therefore, multiple terminals share the same line by confirming that there are no other transmission signals before transmitting. A method called "CSMA (Carrier Sense Multiple Access)" is adopted. At the time of transmission, a waiting time with randomness called "Distributed access Inter Frame Space (DIFS)" and "Contention Window (CW)" is provided, after which there are no other signals to be transmitted. Confirm before sending. Such a method is called “CA (Collision Avoidance)”.

Also, after transmission, it always waits for "ACK (ACKnowledgement, arrival confirmation response)", and if ACK is not returned, it judges that a collision has occurred and retransmits. This is because in the wireless case it is difficult to reliably detect collisions during transmission.

In addition to this, there is, for example, "RTS/CTS (Request to Send/Clear to Send)" devised as a countermeasure against hidden terminals as an access control mechanism unique to wireless LANs. Here, a hidden terminal is a terminal that is outside the radio wave range of itself but is within the radio wave range of the communication partner. Its existence cannot be known directly, but it causes interference.

Assuming that the reach of radio waves is Lm, consider a situation where a communication partner B (access point) of wireless terminal A is Lm ahead, and another wireless terminal C is Lm ahead.

At this time, since the radio wave from terminal C does not reach terminal A, even if terminal A checks whether other terminals are transmitting signals (even if it carries out carrier sensing), terminal C does not know the existence of terminal C. It becomes a hidden terminal of terminal A. If no measures are taken, even if terminal C is transmitting to access point B, terminal A will also transmit data to access point B. This causes collisions at the access point B and becomes a factor that lowers the throughput.

RTS/CTS is a mechanism in which a wireless device transmits a "RTS (transmission request)" packet before transmission, and when the receiving side receives the RTS, it responds with "CTS (receivable)". In the above example, terminal C sends an RTS to access point B first. However, this RTS does not reach terminal A.

After that, access point B notifies terminal C that reception is possible by transmitting CTS. Since this CTS also reaches the terminal A, the terminal A perceives that communication will be performed nearby and postpones the transmission. The RTS/CTS packet describes the expected channel occupation period, during which the terminal that receives the packet suspends communication. This period is called "NAV (Network Allocation Vector, transmission prohibited period)".

The usage statistics of each wireless channel calculated and predicted by channel usage prediction section 1070 from the results of observation and measurement for a predetermined period given from channel usage observation section 201 to channel usage prediction section 1070 are as follows: There is something like

a) Probability of being busy (temporal utilization rate)
b) Probability distribution of duration of busy state and idle state c) Duration of idle/busy state relative to previous busy/idle state duration Occurrence probability distribution (e.g. probability density function (PDF) or cumulative distribution function (CDF))
d) Occurrence pattern of busy state and idle state (period and duty ratio: when background traffic is periodic)

A specific example of the prediction information calculated by channel usage prediction section 1070 will be described below.

1) Calculation method of "occurrence probability distribution of duration of idle state" The probability density function (PDF) p(τ) of the frame arrival interval τ of the wireless LAN is the Pareto (Pareto) distribution is known to follow (see Document 1 below).

Document 1: Dashdorj Yamkhin and Youjip Won, "Modeling and analysis of wireless LAN traffic," Journal of Information Science and Engineering, vol. 25, no. 6, pp. 1783-1801, Nov. 2009.

Here, a is a coefficient that determines the distribution shape, and τ _m is the minimum frame arrival interval.

Also, when a and τ _m are given, the mean μ and variance σ ² of τ are given by the following equations (2) and (3) when a>2.

For example, in the case of the IEEE 802.11 DCF standard, since the minimum arrival interval of data frames is equal to or greater than DIFS+CW, τ _m =DIFS+CWmin is set where CWmin is the minimum value of CW. If μ and σ ² are measured from the channel sensing result with the duration of the idle state as the frame arrival interval, the channel usage prediction unit 1070 can estimate the value of a using the above equation.

Then, when the value of a is obtained, channel usage prediction section 1070 obtains the occurrence probability distribution represented by the following equation as the probability C(τ) that the idle state continues for τ time or longer.

When the radio channel to be used becomes an idle state, the probability that the idle state will continue for t after that time can be obtained from C(τ).

2) As a result of sensing, if the idle (idle) duration time and the busy (busy) duration time are approximately the same each time, and the channel usage prediction unit 1070 determines that the traffic is periodic, then idle ( As the occurrence probability distribution of the duration of the idle state, for example, the idle state from the start of the idle state to the average value of the duration of the idle state (the median value or the minimum value can be used) ) A step function may be used in which the continuation probability is set to 100% and thereafter set to 0%.

3) On the other hand, if the wireless channel to be used is in a busy state, decode the frame length described in the physical header of the incoming packet (frame) and the NAV value described in the MAC frame. By doing so, channel usage prediction section 1070 can acquire the duration of the busy state and predict the duration of the busy state.

It should be noted that the observation of the wireless channel usage status by the channel usage status observation unit 201 and the prediction by the channel usage status prediction unit 1070 are determined by each wireless communication device using the integrated sensing information, and are used for wireless communication. It may be done for multiple radio channels or for one or more radio channels used for wireless communication indicated by the integrated sensing information, respectively.

With the wireless communication device STA and access point AP (information collection device) described above and the configuration of cooperative sensing executed by them, cooperative sensing can be performed with low overhead and unnecessary consumption of radio resources can be avoided. can be done.

In addition, by using the results of cooperative sensing, it is possible to flexibly select channels of multiple frequency bands or use them simultaneously, so that radio resources can be utilized without waste and frequency utilization efficiency can be improved.

Note that, as described above, the transmission control by the transmission control unit 205 may be used when performing cooperative sensing on one radio channel. Then, in a wireless communication device that performs cooperative sensing on such a single wireless channel, sensing results may be used to select a wireless channel to be used in wireless communication. When the wireless channel is determined at the access point AP (information collection device), the sensing results are not integrated at the access point AP and the integrated sensing information is not transmitted to each wireless communication device STA. may

In addition, in the present embodiment, a description has been given on the assumption that the wireless communication device is a wireless LAN terminal. Communication (that is, wireless communication for transmitting and receiving character strings, images, etc., not wireless communication for control, for example, Internet communication via an access point AP) may not be performed. Therefore, the wireless communication device according to this embodiment may be, for example, a device used only for collecting sensing results.

Also, in the present embodiment, a case has been described in which the radio channel used in radio communication is determined according to the sensing result. good too. Therefore, when prediction is not performed, the transmission timing may be controlled according to the integrated sensing information transmitted from the information collection device, and when prediction is performed, according to the integrated sensing information, Channel utilization at a given timing may be predicted. As such, when the integrated sensing information is used to control or predict transmission timing, the sensing result is, for example, information as to whether each wireless channel is busy or idle. may be transmitted frequently from the access point AP to each wireless communication device STA. Also, in such a case, access control section 1080 controlling the transmission timing based on the integrated sensing information may indirectly use the integrated sensing information.

The embodiments disclosed this time are examples of configurations for specifically implementing the present invention, and do not limit the technical scope of the present invention. The technical scope of the present invention is indicated by the scope of claims rather than the description of the embodiments, and includes changes within the scope of the claims and their equivalent meanings. is intended.

200 wireless communication device, 201 channel usage observation unit, 202 sensing result transmission unit, 203 sensing result reception unit, 204 transmission point determination unit, 205 transmission control unit, 300 information collection device, 301, 2100.1 to 2100.3 reception Section 302 Acquisition Section 303 Identification Section 304 Generation Section 305 Transmission Section 1000 Transmission Device 1010 S/P Conversion Section 1020.1 to 1020.3 Radio Frame Generation Section 1030, 2020 Local Oscillator 1040.1 ~ 1040.3, 2400.1 ~ 2400.3 RF section (high frequency processing section), 1050.1 ~ 1050.3, 2010.1 ~ 2010.3 Antenna, 1070 Channel usage prediction section, 1080 Access control section, 1110 Error correction coding unit 1112 interleave unit 2000 receiving device 2500.1 to 2500.3 baseband processing unit 2600 synchronization processing unit 2700 P/S conversion unit 2800 digital signal processing unit.

Claims (3)

A wireless communication device constituting a wireless communication system including an information collecting device and a plurality of wireless communication devices,
a channel usage status observation unit that observes the usage status of a wireless channel that performs random access control;
a sensing result transmission unit for transmitting a sensing result corresponding to the observed usage status to the information collecting device;
receiving a sensing result according to the usage status of the wireless channel observed by the other wireless communication device, which is transmitted from the other wireless communication device to the information collecting device; a sensing result receiving unit configured to receive, from the information collecting device, a notification of the end of a reporting period, which is a period during which sensing results corresponding to usage conditions are transmitted to the information collecting device ;
The transmission time of the sensing result according to the observation by the own device is randomly determined in the reporting time window whose size decreases as the appropriateness indicating that the wireless channel is suitable for use regarding the sensing result is lower. a decision unit;
The sensing result transmitting unit is controlled so that the sensing result of the device is transmitted at the transmission time determined by the transmission time determination unit, and the sensing result of the device is received from another wireless communication device. If the appropriateness is higher than the sensing result, control the sensing result transmission unit so as not to transmit the sensing result of the self device, and if the notification of the end is received, transmit to end the reporting period. and a control unit,
The transmission time determination unit performs transmission within the updated reporting time window in which the longer the non-reporting period, which is the period until the first sensing result is received from the other wireless communication device, the earlier the end. A wireless communications device that updates the transmission time point to be a time point. The radio communication device transmits a signal using a plurality of radio channels in which random access control is performed in each of a plurality of frequency bands separated from each other,
a digital signal processing unit for dividing transmission data into a plurality of partial data corresponding to each of the plurality of frequency bands and generating transmission packets for each of the frequency bands;
a plurality of high-frequency processing units provided for each of the frequency bands for converting the digital signal generated by the digital signal processing unit into a high-frequency signal for each of the corresponding frequency bands;
a local oscillator provided in common to the plurality of high-frequency processing units for generating a clock signal used by the plurality of high-frequency processing units;
The channel usage status observation unit observes the usage status of the plurality of radio channels in the plurality of frequency bands,
The sensing result receiving unit also receives integrated sensing information, which is a result of integrating sensing results from a plurality of wireless communication devices, from the information collecting device,
Based on the integrated sensing information, the digital signal processing unit and the high frequency processing unit are controlled, and each of the partial data is processed as a packet for each of the plurality of frequency bands by the plurality of wireless channels at the same timing in synchronization. 2. The wireless communication device of claim 1, further comprising an access controller that transmits at . A wireless communication device constituting a wireless communication system including an information collecting device and a plurality of wireless communication devices, comprising: a channel usage status observation unit; a sensing result reception unit; a transmission time determination unit; a sensing result transmission unit; A wireless communication method processed using a unit,
a step in which the channel usage status observation unit observes the usage status of a radio channel on which random access control is performed;
a step in which the sensing result receiving unit receives a sensing result transmitted from another wireless communication device to the information collecting device;
The transmission time determination unit sets the transmission time of the sensing result according to the observation by the own device to a reporting time window whose size decreases as the degree of appropriateness indicating that the wireless channel is suitable for use regarding the sensing result is lower. randomly determining in
If the sensing result of its own device is more appropriate than the sensing result received from the other wireless communication device up to the time of transmission, the sensing result transmitting unit transmits the sensing result of its own device to the If the sensing result of the device is not transmitted to the information collection device and the sensing result of the device is less appropriate than the sensing result received from the other wireless communication device up to the transmission time, the device is sent to the information collection device at the transmission time a step of transmitting the sensing result of to the information collecting device;
The sensing result receiving unit receives, from the information gathering device, a notification of the end of a reporting period, which is a period during which sensing results according to the wireless channel usage observed by the plurality of wireless communication devices are transmitted to the information gathering device. and
a step in which the transmission control unit ends the reporting period when the notification of the end is received;
The longer the non-reporting period , which is the period until the first sensing result is received from the other wireless communication device, the earlier the transmission within the updated reporting time window. and updating the transmission time point to be a time point.

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