Communication device, communication method, and program

Abstract

To reduce a period required for a communication device operating as an access point to receive necessary information from a plurality of communication devices operating as access points.SOLUTION: A communication device 100 operating as an access point transmits a frame having first information indicating that communication devices 104, 105, 106 operating as access points transmit information on these devices to the communication device 100 and second information indicating an RU used by the communication devices 104, 105, 106 to transmit the first information, and receives in parallel a response frame to the transmitted frame including the information on the communication devices 104, 105, 106 by using orthogonal frequency-division multiple access (OFDMA) in the RU indicated in the second information.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a communication device that performs wireless communication and a wireless communication method.

Background Art

[0002] With the recent increase in the amount of data to be communicated, the development of communication technologies such as wireless LAN (Local Area Network) has been promoted. As the main communication standards for wireless LAN, the IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard series is known. The IEEE 802.11 standard series includes standards such as IEEE 802.11a / b / g / n / ac / ax.

[0003] In IEEE 802.11ax described in Patent Document 1, a technique for improving the communication speed under congested conditions in addition to a high peak throughput of up to 9.6 gigabits per second (Gbps) has been standardized by OFDMA. Note that OFDMA is an abbreviation for Orthogonal Frequency-Division Multiple Access.

[0004] As a successor standard aiming for further throughput improvement, improvement in frequency utilization efficiency, and improvement in communication latency, a Task Group for formulating the IEEE 802.11be (hereinafter referred to as 11be) standard has been established.

[0005] In 11be, a technique that enables improvement in communication performance such as improvement in communication rate and reduction of radio wave interference using beamforming by cooperative operation of a plurality of APs (Access Points) and performing data communication with a STA (Station) is being studied.

[0006] As an example of the cooperative operation of multiple APs, a distributed MIMO technology based on the MIMO (Multi-Input Multi-Output) technology that uses multiple transmit and receive antennas at the same time and on the same channel can be cited. In distributed MIMO, in an environment where multiple APs and multiple STAs exist, information about the communication state and the state of each AP is shared among the multiple APs, and data is sent from the APs to the STA at the same timing. By having multiple APs cooperate in this way, the number of spatial streams can be increased compared to the case of communicating with a single AP, so an improvement in throughput is expected.

[0007] Such a communication technology in which multiple APs cooperate is called Multi-AP communication, and the APs are classified into one master AP that manages other APs and slave APs that operate under the management of the master AP.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] In Multi-AP communication, before an AP performs data communication with an STA, it is necessary to determine a slave AP that participates in Multi-AP communication from among the APs existing in the vicinity of the master AP. Also, in order to determine a slave AP, it is necessary to receive information such as the congestion situation and the availability of participation in Multi-AP communication from among the APs existing in the vicinity of the master AP. However, when multiple APs exist in the vicinity of the master AP, if communication is performed one-to-one and in order with these multiple APs, it will take time to receive information from all of them.

[0010] Therefore, an object of the present invention is to shorten the time until a communication device operating as an access point receives necessary information from a plurality of communication devices operating as access points.

Means for Solving the Problems

[0011] In order to achieve the above object, a communication device according to an aspect of the present invention is a communication device operating as an access point of a communication network, generation means for generating a frame having first information indicating that each of a plurality of other communication devices operating as access points of the communication network transmits its own device information to the communication device, and second information indicating frequency components assigned to each of the plurality of other communication devices; transmission means for transmitting the frame generated by the generation means to the plurality of other communication devices; receiving means for receiving in parallel, using orthogonal frequency division multiple access (OFDMA), response frames transmitted in the frequency components assigned to each of the plurality of other communication devices and including information of each of the plurality of other communication devices; and has.

Effects of the Invention

[0012] According to the present invention, by transmitting a frame having first information indicating that the communication device transmits its own device information to a plurality of other communication devices and second information indicating frequency components assigned to each of the plurality of other communication devices to the plurality of other communication devices, and receiving responses from the plurality of other communication devices in parallel using OFDMA, the time until necessary information is received from the plurality of other communication devices can be shortened.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the configurations shown in the following embodiments are merely examples, and the present invention is not limited to the illustrated configurations.

[0015] FIG. 1 shows the configuration of the communication network constructed by the communication device 100 according to the present embodiment. The communication device 104 is an access point (hereinafter referred to as AP) having a role of constructing the wireless communication network 101. Further, the communication device 105 is an AP having a role of constructing the wireless communication network 102, and the communication device 106 is an AP having a role of constructing the wireless communication network 103. The communication devices 107 and 108 are stations (hereinafter referred to as STAs) having a role of participating in the wireless communication networks 101, 102, and 103. In the present embodiment, the communication device 100 functions as a master AP that manages other APs, and the communication devices 104 to 106 are APs existing in the vicinity of the master AP, and a slave AP is determined from among the communication devices 104 to 106.

[0016] The communication devices 100, 104 to 108 can perform wireless communication compliant with the IEEE802.11be standard. Note that IEEE is the abbreviation of Institute of Electrical and Electronics Engineers. The communication devices 104 to 108 can communicate in frequency bands of 2.4 GHz, 5 GHz, and 6 GHz. Also, the communication devices 100, 104 to 108 can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz.

[0017] The communication devices 100, 104 to 108 can achieve multi-user (MU) communication by performing OFDMA communication compliant with the IEEE802.11be standard, multiplexing signals of multiple users. OFDMA is the abbreviation of Orthogonal Frequency Division Multiple Access. In OFDMA communication, RUs (Resource Units), which are part of the divided frequency components, are allocated to each communication device so that they do not overlap with each other, and the carriers of each STA are orthogonal. Therefore, the AP can communicate with multiple communication devices in parallel.

[0018] Note that although the communication devices 100, 104 to 108 are assumed to be compliant with the IEEE802.11be standard, in addition to this, they may also be compliant with legacy standards that are older than the IEEE802.11be standard. Specifically, the communication devices 100, 104 to 108 may be compliant with at least any one of the IEEE802.11a / b / g / n / ac / ax standards. Also, in addition to the IEEE802.11 series standards, they may be compliant with other communication standards such as Bluetooth (registered trademark), NFC, UWB, ZigBee, MBOA, etc. Note that NFC is the abbreviation of Near Field Communication. Also, UWB is the abbreviation of Ultra Wide Band, and MBOA is the abbreviation of Multi Band OFDM Alliance. UWB includes wireless USB, wireless 1394, WiNET, etc. Also, they may be compliant with communication standards for wired communications such as wired LAN.

[0019] Specific examples of the communication devices 100, 104 to 106 include, but are not limited to, wireless LAN routers and personal computers (PCs). Also, the communication devices 104 to 106 may be information processing devices such as wireless chips that can execute wireless communication compliant with the IEEE802.11be standard. Also, specific examples of the communication devices 107 to 108 include, but are not limited to, cameras, tablets, smartphones, PCs, mobile phones, video cameras, etc. Also, the communication devices 107 to 108 may be information processing devices such as wireless chips that can execute wireless communication compliant with the IEEE802.11be standard. Also, although the wireless network in FIG. 1 is composed of three APs and two STAs, the number of APs and STAs is not limited to this.

[0020] FIG. 2 shows the hardware configuration of the communication devices 100, 104 to 108 in this embodiment. The communication device 100 includes a storage unit 201, a control unit 202, a functional unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207.

[0021] The storage unit 201 is composed of one or more memories such as ROM and RAM, and stores programs for performing various operations described later and various information such as communication parameters for wireless communication. Here, ROM is an abbreviation for Read Only Memory, and RAM is an abbreviation for Random Access Memory. In addition to memories such as ROM and RAM, as the storage unit 201, storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs may be used. Also, the storage unit may include a plurality of memories and the like.

[0022] The control unit 202 is composed of one or more processors such as a CPU or an MPU, and controls the entire communication device 100 by executing the computer program stored in the storage unit 201. CPU is an abbreviation for Central Processing Unit, and MPU is an abbreviation for Micro Processing Unit. Note that the control unit 202 may control the entire communication device 100 in cooperation with the computer program stored in the storage unit 201 and the OS (Operating System). Also, the control unit 202 generates data and signals to be transmitted in communication with other communication devices. Further, the control unit 202 may include a plurality of processors such as a multi-core, and control the entire communication device 100 by the plurality of processors.

[0023] Also, the control unit 202 controls the functional unit 203 to execute predetermined processes such as imaging, printing, and projection. The functional unit 203 is hardware for the AP and STA to execute predetermined processes. For example, when the AP and STA are cameras, the functional unit 203 is an imaging unit and performs imaging processing. Also, for example, when the AP and STA are printers, the functional unit 203 is a printing unit and performs printing processing. Also, for example, when the AP and STA are projectors, the functional unit 203 is a projection unit and performs projection processing. The data processed by the functional unit 203 may be data stored in the storage unit 201, or may be data communicated with other APs and STAs via the communication unit 206 described later.

[0024] The input unit 204 receives various operations from the user. The output unit 205 performs various outputs to the user via a monitor screen or a speaker. Here, the output by the output unit 205 may be a display on the monitor screen, an audio output by the speaker, a vibration output, or the like. Note that both the input unit 204 and the output unit 205 may be realized by one module such as a touch panel. Further, the input unit 204 and the output unit 205 may be integrated with the communication device 100 or may be separate.

[0025] The communication unit 206 controls wireless communication compliant with the IEEE802.11 series standards. Further, it may control wired communication such as a wired LAN. The communication unit 206 controls the antenna 207 to transmit and receive signals for wireless communication generated by the control unit 202. Note that when the communication device 100 supports NFC (Near Field Communication) standards, Bluetooth standards, etc. in addition to the IEEE802.11be standard, it may control wireless communication compliant with these communication standards. Further, when the communication device 100 can execute wireless communication compliant with a plurality of communication standards, it may have a configuration with a communication unit and an antenna corresponding to each communication standard separately. The communication device 100 communicates data such as image data, document data, and video data with the communication devices 107 and 108 via the communication unit 206.

[0026] FIG. 3 shows an example of the format of a trigger frame in the present embodiment. The trigger frame is a frame in which the AP assigns an RU to each STA, and each STA uses the assigned RU to prompt the STA to transmit data to the AP. Further, since each STA uses the RU assigned by the AP, each STA can transmit data to the AP in parallel.

[0027] Fig. 9 shows the size of the RUs allocated by the AP. In this figure, the allocation of RUs when the communication device 100 uses a bandwidth of 20 MHz is shown. The RU allocation shown in this figure is performed in the RU Allocation subfield described later. 901 shows the size of the RUs when RUs are allocated to 9 STAs. The 20 MHz is divided into 256 subcarriers on the frequency axis, and a plurality of these subcarriers grouped together form an RU. In this case, the size of the RU allocated to each STA by the AP is 26. The size of the RU indicates how many subcarriers are used for one RU. The fact that the size of the RU is 26 means that 26 subcarriers are used. Also, 902, 903, and 904 respectively show the sizes of the RUs when RUs are allocated to 5 STAs, 3 STAs, and 1 STA.

[0028] In the present embodiment, Fig. 3 is a frame transmitted by the communication device 100 to the communication devices 104 to 106 that are APs (hereinafter referred to as nearby APs) present in the vicinity, and is a frame indicating that information of the communication devices 104 to 106 is transmitted. Here, the nearby AP refers to an AP that exists within a range where the communication device 100 can receive a Beacon frame.

[0029] In FIG. 3, the fields / sub-fields shown as 301 to 313 conform to the format defined in IEEE802.11ax. The Trigger Type 309 in Common Info 305 specifies the type of trigger by the trigger frame. Also, Length 310 represents the common communication period of all communication devices. Also, BW 311 is a field that includes information indicating the bandwidth of the channel used when transmitting data from a neighboring AP to a master AP. For example, assume that the BW 311 sub-field values include 0, 1, and 2, and the corresponding frequency bandwidths are 20 MHz width, 40 MHz width, and 80 MHz width. At this time, when the value 1 is indicated in the BW 311 sub-field, it is shown that the available frequency bandwidth of the neighboring AP is 40 MHz. Also, when the value of the BW 311 sub-field is 1 or more, the neighboring AP may transmit information using a frequency bandwidth corresponding to a value less than or equal to that value when transmitting the information of the neighboring AP to the communication device 100. For example, when the value 2 is indicated as the value of BW 311, the neighboring AP may transmit information using 20 MHz width, 40 MHz width, and 80 MHz width.

[0030] Table 1 exemplifies the correspondence between the Trigger Type sub-field values and the types of triggers in Trigger Type 309.

[0031]

Table 1

[0032] Trigger Type is represented by 4 bits. In this embodiment, when the Trigger Type sub-field value is 8, it indicates that the neighboring AP transmits its own information to the master AP. User Info306♯1 to User Info306♯N include an identifier, AID (Association ID) 312, RU Allocation 313, etc. AID 312 is represented by 12 bits. Here, when storing the AID, which is the identification information assigned when the connection is established, into AID 312, the lower 12 bits of the AID are stored. Therefore, in Table 2, the subfield of AID 312 is specified as the AID12 subfield. Regarding AID 312, it will be described later using Table 2.

[0033] RU Allocation 313 is the allocation of RUs, which are frequency components used when transmitting the information of neighboring APs to the master AP. The specific RU allocation is as shown in FIG. 9 described above. Among the RUs, there are RUs that can be used only by communication devices whose lower 12 digits of the AID value, which is the identification information assigned when the connection is established, match the AID subfield value, and RA-RUs (Random Access-Resource Units) that can be used by multiple communication devices. It is assumed that RA-RUs are allocated to communication devices that have not established a connection and have no AID assigned, communication devices that have established a connection but have resumed from the sleep state, communication devices with a low priority, etc.

[0034] Table 2 shows the relationship between the subfield value of AID 312 in User Info306 and its meaning.

[0035]

Table 2

[0036] Note that the STA described in Table 2 includes the AP. Each neighboring AP determines whether it is its own dedicated User Info based on the identification information, which is the value stored in the AID12 subfield.

[0037] When the value of 1 - 2007 is included in the AID12 subfield, it indicates that it is User Info for the STA whose lower 12 digits of the AID assigned when the connection was established are equal to the value of the AID12 subfield. Also, when the value 2045 is included in the AID12 subfield, it indicates that the connection has not been established and it is UserInfo for the STA to which no AID has been assigned. Also, 2047 of the value of the AID12 subfield is a newly defined field value, and when 2047 is included in the AID12 subfield, it indicates that the connection has not been established and it is User Info for the AP to which no AID has been assigned.

[0038] When the communication device 100 and the nearby AP have established a connection, User Info 306♯1 to 306♯N includes as many as the number of nearby APs. However, when the communication device 100 and the nearby AP have not established a connection, they share the User Info in which 2045 or 2047 is stored in the value of the AID12 subfield.

[0039] Also, the communication device 100 manages OBO (OFDMA random access Back - Off) which serves as a timer so that the nearby AP does not competitively use the RU or RA - RU assigned by the communication device 100. OBO is randomly assigned by the communication device 100. When the value obtained by subtracting the number of RA - RUs assigned by the communication device 100 from the initial value of OBO is the same as or less than the number of RA - RUs assigned by the communication device 100, the nearby AP transmits a response frame using the assigned RA - RU. When the value obtained by subtracting the number of RA - RUs assigned by the communication device 100 from the initial value of OBO is greater than the number of RA - RUs assigned by the communication device 100, the nearby AP reduces the number of RA - RUs assigned by the communication device 100 by that amount and waits until the next trigger frame is transmitted.

[0040] In this embodiment, when the communication device 100 and the nearby AP have not established a connection, in order for the communication device 100 to transmit its own information to the nearby AP, the Trigger Type subfield value is set to 8. Also, the communication device 100 sets the value of the AID12 subfield to 2045 or 2047 in order to allocate the RU used when the nearby AP transmits information. When the communication device 100 and the nearby AP have not established a connection, since the nearby AP has not been assigned an AID, by setting the AID12 subfield value of the communication device 100 to 2045 or 2047, the nearby AP can transmit information using the RA-RU. Here, when the AID12 subfield value is set to 2045, as shown in Table 2, since a non-connected STA can also be used, the RA-RU available to the nearby AP may conflict with the STA. However, when the AID12 subfield value is 2047, since it is a field indicating the RA-RU that can be used only by non-connected APs, the nearby AP can use the RA-RU without conflicting with the STA.

[0041] Also, similarly, when the communication device 100 and the nearby AP have established a connection, in order for the communication device 100 to transmit the information of the nearby AP to the communication device 100, the Trigger Type subfield value is set to 8. Also, the communication device 100 sets the value of the AID12 subfield to the lower 12 digits of the value of the AID assigned when the connection was established in order to allocate the RU used when the nearby AP transmits its own information.

[0042] Furthermore, when the communication device 100 and the nearby AP have not established a connection, even when the Trigger Type subfield value is set to 0 and the value of the AID12 subfield is set to 2047, it also indicates that the nearby AP transmits its own device information to the communication device 100. Here, in the IEEE802.11ax standard, setting the Trigger Type subfield value to 0 and storing the AID subfield values 0 - 2046 in Table 2 indicates performing UL MU (Up Link Multi-User) transmission. However, by the fact that the Trigger Type subfield value is 0 and the AID subfield value stores 2047, which is the newly defined AID12 subfield value, it can be interpreted that the nearby AP indicates transmitting its own device information to the communication device 100.

[0043] Also, when the communication device 100 transmits a trigger frame, depending on the connection status of the nearby AP and the like, the communication device 100 can select the value of the Trigger Type subfield, or the user may set the value of the Trigger Type subfield. For example, when there is a nearby AP with which a connection has been established, the Trigger Type subfield value may be set to 8, and when there is no nearby AP with which a connection has been established, the Trigger Type subfield value may be set to 0.

[0044] Fig. 4 shows an example of a Multi-AP Group formation Response frame Action Field format, which is a response frame for the trigger frame in this embodiment. The response frame conforms to a format similar to a management frame such as an Action frame.

[0045] At BSSID2 409, the BSSID of the neighboring AP is included, and at Buffer Status410, information on the Buffer Status of the neighboring AP is included. The master AP can grasp the accumulation status of data in the buffer of the neighboring AP from the Buffer Status. At Multi-AP participation411, it is possible to store whether or not to participate in the Multi-AP. Also, at Number of STA412, the number of STAs that have established a connection with the neighboring AP is stored, and at AID List413, a list of AIDs assigned to the STAs that have established a connection is stored. Furthermore, at Trigger frame signal intensity414, information regarding the intensity of the received trigger frame is stored. From Trigger frame signal intensity414, the communication device 100 can grasp the distance between the communication device 100 and the neighboring AP. The communication device 100 determines the slave AP from the information of the response frame for the trigger frame.

[0046] FIG. 5 is a flowchart showing the flow of processing performed when the control unit 202 executes a program stored in the storage unit 201 of the communication device 100 which is the master AP. This flowchart explains the flow of processing for the communication device 100 to transmit a trigger frame indicating that it transmits its own device information to the neighboring AP and determine the slave AP based on the information of the received response frame.

[0047] This flowchart is started when the wireless LAN function is started, such as when the user sets the communication device 100 to perform Multi-AP communication, when the power of the communication device 100 is turned on, or when the wireless LAN function of the communication device 100 is turned on. Also, this flowchart may be started when the communication device 100 can no longer receive the Beacon frame of the slave AP, for example, when performing Multi-AP communication but the slave AP for performing Multi-AP communication moves out of the communication range.

[0048] The communication device 100 monitors the Beacon frames transmitted by surrounding APs (S501). Next, the communication device 100 determines whether it has received the Beacon frame transmitted by the nearby AP (S502). In S502, if it is determined that the Beacon frame has been received, in S503, it is determined whether a predetermined time has elapsed. By allowing the predetermined time to elapse, a plurality of Beacon frames can be received. In S502, if it is determined that the Beacon frame has not been received, the process returns to S501, and the Beacon frame from the nearby AP is monitored again. In S503, if it is determined that the predetermined time has not elapsed, the process returns to S501 again, and the Beacon frame from the nearby AP is monitored. In S503, if it is determined that the predetermined time has elapsed, the communication device 100 determines whether the number of nearby APs that have received the Beacon frame and whose presence has been detected is two or more (S504). The number of nearby APs is managed in the functional unit of the communication device 100. If there are two or more nearby APs, the communication device 100 transmits a trigger frame to the nearby APs that have received the Beacon frame (S505). This trigger frame includes information indicating that the communication device transmits its own information to the nearby AP, and RU information used when the nearby AP transmits its information to the communication device 100. Here, the information indicating that the communication device 100 transmits its own information to the nearby AP is included in the Trigger Type subfield of the Common Info field, and the RU information is included in the RU Allocation of the User Info field. Note that if it is detected from the information of the received Beacon frame that the nearby AP does not support 11be, it may not be necessary to transmit the trigger frame.

[0049] In S506, it is determined whether the communication device 100 has received a response frame. Information of the neighboring APs included in the response frame includes the received signal strength regarding the trigger frame received by the neighboring AP, information of the STAs that have established connections with the neighboring AP, information on whether to participate in Multi-AP communication, and the like. The channel used when the communication device 100 receives a response frame from a neighboring AP is determined from the Beacon frame information of the neighboring AP received by the communication device 100. Also, the RUs used when the neighboring AP transmits a response frame may be assigned to each communication device from within one channel, or may be assigned from among a plurality of channels. For example, when the neighboring AP transmits information of the neighboring AP with a frequency bandwidth of 80 MHz, four 20-MHz-wide channels are used. Among the four channels used at this time, the communication devices 104 to 106 can use a plurality of RUs or RA-RUs from within one channel, and can also use RUs or RA-RUs from among a plurality of different channels. Here, the frequency bandwidth and the number of channels are not limited to this. Also, a neighboring AP that does not participate in Muti-AP communication does not have to transmit a response frame to the communication device 100 for the trigger frame.

[0050] In S506, when it is determined that the communication device 100 has received a response frame, based on the information transmitted by the neighboring AP, the communication device 100 determines a slave AP from among the neighboring APs (S509). As a method for determining the slave AP, for example, a method of selecting an AP with a high radio wave intensity of the trigger frame received by the neighboring AP, a method of selecting an AP with a large number of connected STAs, etc. can be considered, but it is not limited to this. As a selection method, for example, a neighboring AP determined to have a radio wave intensity indicated by the Trigger frame signal intensity 414 of the response frame transmitted by the neighboring AP to the communication device 100 higher than a reference value may be preferentially selected. The reference value may be set by the user, or when there is no user setting, the default setting held in the storage unit 201 is used. An upper limit may be determined in advance for the number of slave APs, and not all neighboring APs have to be slave APs.

[0051] In S506, if it is determined that the communication device 100 has not received the response frame, the process ends. If it is determined that the response frame has not been received, it may be the case that the neighboring AP is a communication device that does not support the 11be standard, or that although it supports the 11be standard, it is determined not to participate in Muti-AP communication, and the neighboring AP does not transmit a response frame to the communication device 100, etc.

[0052] The communication device 100 transmits a slave AP determination notification frame to the AP determined to be the slave AP to notify that it has been determined to be the slave AP (S510). If it does not become the slave AP, it may or may not transmit a slave AP determination notification frame notifying that it has not become the slave AP.

[0053] In S504, if there are not two or more neighboring APs, that is, if there is one neighboring AP, the communication device 100 transmits a frame to the neighboring AP (S507). The frame is, for example, a frame compliant with a management frame such as an Action frame. The frame transmitted by the communication device 100 to the neighboring AP includes information indicating that the information of the neighboring AP is to be transmitted to the communication device 100. When there is one neighboring AP, since it is not necessary to transmit and receive the information of a plurality of communication devices in parallel, the trigger frame and OFDMA may not be used.

[0054] In S508, it is determined whether the communication device 100 has received a response frame. In S508, if it is determined that the response frame has been received, the communication device 100 determines a slave AP from among the neighboring APs based on the information received (S509). The method for determining the slave AP is as described above.

[0055] In S510, if it is determined that the response frame has not been received, the process ends.

[0056] The specific examples of the processing of the flowchart in FIG. 5 will be described with reference to FIGS. 6 to 8 below.

[0057] FIG. 6 is a sequence diagram showing that the communication device 100 stores the newly defined Trigger Type subfield value and transmits its own information to the communication devices 104 to 106, and determines a slave AP based on the information. By setting the Trigger Type subfield value of the trigger frame to 8 and the AID12 subfield value to 2045 or 2047 and transmitting it to the communication devices 104 to 106 which are neighboring APs, it shows that the communication device 100 transmits its own information to the communication devices 104 to 106.

[0058] The communication device 100 detects that there is an AP in the vicinity by receiving the Beacon frames transmitted by the communication devices 104 to 106 (M6011). When the Beacon frame is received, a Multi-AP group formation trigger frame is generated by setting the Trigger Type subfield value to 8 and transmitted to the communication devices 104 to 106 (M6012). In this embodiment, since the communication device 100 and the communication devices 104 to 106 have not established a connection, the communication devices 104 to 106 are not assigned an AID. Therefore, by setting the AID12 subfield value to 2045 or 2047, the communication devices 104 to 106 use the RUs available to the communication device without an assigned AID to transmit their own information to the communication device 100 (M6013).

[0059] The communication device 100 determines a slave AP from the received information of the communication devices 104 to 106 (M6014). The sequence diagram in FIG. 6 shows the case where the communication devices 104 and 105 become slave APs. In M6015, a slave AP determination notification frame is transmitted to the communication devices 104 and 105. Since the communication device 106 does not become a slave AP, the slave AP notification is not transmitted. After the slave AP is determined, the communication device 100 may periodically transmit the same trigger frame as the trigger frame to some or all of the slave APs to obtain information related to the latest slave AP.

[0060] 7 is a sequence diagram in which communication device 100 determines a slave AP when communication device 100 and communication devices 104-106 have already established a connection and an AID has been assigned to each of communication devices 104-106 before starting the slave AP determination process. Communication device 100 sets the Trigger Type subfield value to 8, stores the value of the AID that has already been assigned, and transmits a trigger frame to indicate to communication devices 104-106 that it will transmit information about its own device to communication device 100.

[0061] The communication devices 104 to 106 transmit association request frames to the communication device 100 (M7011). The communication device 100 transmits an association response frame in response to the received association request frame (M7012). As a result, a connection is established between the communication device 100 and the communication devices 104 to 106.

[0062] When a Beacon frame is received (M7013), a Multi-AP group formation trigger frame is generated by setting the Trigger Type subfield value to 8, and transmitted to the communication devices 104 to 106 (M7014). In this embodiment, the trigger frame is transmitted in response to reception of a Beacon frame, but the trigger frame may also be transmitted in response to transmission of an Association Response frame.

[0063] The AID12 subfield value of the AID field 312 included in the User Info Field stores the value assigned to the communication devices 104 to 106 with which a connection has been established. The set of User Info 306 including the AID field 312 includes the same number of nearby APs with which a connection has been established with the communication device 100. The communication devices 104 to 106 that have received the trigger frame transmit information about their own devices to the communication device 100 (M7015).

[0064] The process after the slave AP is determined is as described above.

[0065] In this embodiment, since the communication device 100 has established connections with the communication devices 104 to 106, the information sent from the slave AP to the communication device 100 after the slave AP is determined also includes information that changes dynamically. For example, the position of the slave AP changes, the distance between the communication device 100 and the slave AP increases and communication becomes impossible, the position of the STA connected to the slave AP changes and the channel performance between the slave AP and the STA changes, etc. are conceivable. The information that changes dynamically is obtained from the information of the Beacon frames sent by the communication devices 104 to 106 that the communication device 100 is receiving.

[0066] FIG. 8 shows a sequence diagram in which the communication device 100 determines a slave AP based on information by transmitting its own information to the communication devices 104 to 106 by setting an existing Trigger Type subfield value. The communication device 100 sets the Trigger Type subfield value to 0 and the AID12 subfield value to 2047 to indicate to the communication devices 104 to 106 that they should transmit their own information to the communication device 100.

[0067] The communication device 100 detects the presence of an AP in the vicinity by receiving the Beacon frames transmitted by the communication devices 104 to 106 (M8011). When a Beacon frame is received, a trigger frame indicating that the communication devices 104 to 106 should transmit their own information to the communication device 100 is generated and transmitted to the communication devices 104 to 106 (M8012). In the IEEE802.11ax standard, when the Trigger Type subfield value is 0, it indicates a trigger frame for UL MU (Up Link Multi-User) transmission. However, since the Trigger Type subfield value is 0 and the AID12 subfield value is 2047, the communication devices 104 to 106 interpret that it is a frame for transmitting their own information to the communication device 100. The communication devices 104 to 106 that have received the trigger frame transmit their own information to the communication device 100 using the RU specified by the communication device 100 (M8013).

[0068] The process after determining the slave AP is as described above.

[0069] As described above, the communication device 100 of the present embodiment transmits a trigger frame having information indicating that the device's own information is transmitted to the communication device 100 to a plurality of neighboring APs and information on RUs assigned to the plurality of neighboring APs. The communication device 100 receives information in parallel using OFDMA for the response frame to the trigger frame. Therefore, compared with the case where the communication device 100 communicates with a plurality of neighboring APs one-to-one in order and receives information from the plurality of neighboring APs, the time until the necessary information is received can be shortened.

[0070] Also, by shortening the time until the necessary information is received from the plurality of neighboring APs, the communication device 100 can efficiently select the slave AP and can start Multi-AP communication earlier.

[0071] In addition, a recording medium recording the program code of software for realizing the above functions may be supplied to the system or device, and the computer (CPU, MPU) of the system or device may read and execute the program code stored in the recording medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the above-described device.

[0072] As the storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, a ROM, a DVD, etc. can be used.

[0073] In addition, by executing the program code read by the computer, not only the above-described functions are realized, but also based on the instructions of the program code, the OS running on the computer performs part or all of the actual processing to realize the above-described functions. The OS is an abbreviation for Operating System.

[0074] Furthermore, the program code read from the storage medium is written into the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer. Then, based on the instructions of the program code, the CPU provided in the function expansion board or the function expansion unit performs part or all of the actual processing to realize the above-described functions.

[0075] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and having one or more processors in the computer of the system or apparatus read and execute the program. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

Description of Reference Numerals

[0076] 201 Storage unit 202 Control unit 203 Functional unit 204 Input unit 205 Output unit 206 Communication unit 207 Antenna

Claims

1. A communication device that operates as an access point for a communication network, comprising: a generating means for generating a frame having first information indicating that each of a plurality of other communication devices operating as an access point of a communication network transmits information of its own device to said communication device, and second information indicating a frequency component assigned to each of said plurality of other communication devices; a transmitting means for transmitting the frame generated by the generating means to the plurality of other communication devices; a receiving means for receiving, in parallel, a response frame including information of each of the other communication devices, the response frame being transmitted in a frequency component assigned to each of the other communication devices using an orthogonal frequency division multiple access (OFDMA); A communication device comprising:

2. 2. The communication device according to claim 1, further comprising: a communication device that operates under the management of the communication device is determined from among the plurality of other communication devices based on information contained in the response frame received by the receiving means.

3. 3. The communication device according to claim 1, wherein the frame has a format conforming to a trigger frame defined in IEEE 802.11ax.

4. 4. The communication device according to claim 1, wherein the first information is included in a Common Info field of the frame, and the second information is included in a User Info field of the frame.

5. The communication device according to claim 1 , wherein the first information is included in a Trigger Type subfield of a Common Info field.

6. The communication device according to claim 1 , wherein the value included in the Trigger Type subfield in the first information is 0 or 8.

7. The communication device according to claim 1 , wherein the second information is included in an RU Allocation subfield of a User Info field of the frame.

8. 8. The communication device according to claim 1, wherein the second information is a resource unit (RU).

9. 9. The communication device according to claim 1, wherein the frame further includes first identification information which is an identifier of the communication device, and the communication device assigns the second information which is usable by the communication device.

10. The communication device according to any one of claims 1 to 9, characterized in that the communication device assigns the second information indicating the frequency components assigned to each of the multiple other communication devices based on the first identification information and second identification information assigned when a connection is established with the multiple other communication devices.

11. 11. The communication device according to claim 9, wherein the first identification information is included in a User Info field of the frame.

12. The communication device according to claim 9 , wherein the first identification information is included in an AID (Association ID) subfield of a User Info field.

13. The communication device according to claim 10, wherein the second identification information is an AID (Association ID).

14. 14. The communication device according to claim 1, wherein the communication device operates as an access point conforming to the IEEE 802.11be standard.

15. 15. The communication device according to claim 1, wherein the other communication device operates as an access point conforming to the IEEE 802.11be standard.

16. A communication device that operates as an access point for a communication network, comprising: a receiving means for receiving a frame from the other communication devices, the frame having first information indicating that information of the communication device is to be transmitted to the other communication devices operating as an access point of a communication network and second information indicating frequency components assigned to each of the communication devices; and a transmitting means for transmitting a response frame, which is a response to the frame received by the receiving means and includes information of the communication device, in parallel using orthogonal frequency division multiple access (OFDMA) at the frequency components indicated by the second information. A communication device comprising:

17. A communication method between a first communication device operating as an access point of a communication network and a plurality of second communication devices different from the first communication device, comprising: a generating step of the first communication device generating a frame having first information indicating that each of the plurality of second communication devices operating as an access point of a communication network transmits information of the respective device to the first communication device, and second information indicating a frequency component assigned to each of the plurality of second communication devices; a first transmission step of transmitting the frame generated by the generation step to the plurality of second communication devices; a second transmission step of transmitting, in response to receiving the frame, a response frame including information of the second communication device at a frequency component indicated by the second information; The first communication device further includes a receiving step of receiving the response frame transmitted by the second transmitting step in parallel using an orthogonal frequency division multiple access (OFDMA); A communication method comprising:

18. A program for causing a computer to function as each of the means of the communication device according to any one of claims 1 to 16.

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