Communication device, control method, and program

Abstract

This invention provides a communication device, communication method, control method, and program that efficiently utilize frequency resources in a communication system using a communication link composed of multiple channels. [Solution] In a communication system, a communication device using a wireless frame compliant with the IEEE 802.11 standard series has a first frequency band in which it is using, and a second frequency band and a third frequency band that other communication devices can handle. In frequency division multiplexing communication between multiple devices, including other communication devices, if the frequency resources of the second frequency band are allocated to a device other than other communication devices, the device obtains capability information from other communication devices indicating whether it has the capability to change the frequency band used from the second frequency band to a fourth frequency band that includes a part of the third frequency band and perform frequency division multiplexing communication, allocates the frequency resources to the other communication device, and communicates with that other communication device.

Description

Technical Field

[0004] , ,

[0001] The present invention relates to data communication technology in a communication device capable of communicating using a communication link composed of a plurality of channels.

Background Art

[0002] In recent years, with the 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 Electronic Engineers) 802.11 standard series is known. The IEEE 802.11 standard series includes IEEE 802.11a / b / g / n / ac / ax / be standards, etc. For further improvement of communication reliability, the development of the IEEE 802.11bn standard is underway as a successor standard to the IEEE 802.11be standard. In the IEEE 802.11WG (Working Group) that formulates the IEEE 802.11bn standard, in the UHR SG, the goals and scope of study of this standard are determined, and in TGbn, the detailed technical content to be included in this standard is planned to be defined. Note that UHR SG is an abbreviation for Ultra High Reliability Study Group. Also, TGbn is an abbreviation for Task Group bn.

[0003] As one of the candidate technologies included in the IEEE 802.11bn standard, a technology for efficiently using frequency resources in a communication method using a communication link composed of a plurality of channels is being studied. For example, Patent Document 1 describes a technology for performing communication using other channels when the Primary Channel used to acquire the transmission right cannot be used.

Prior Art Documents

Patent Documents

[0004] [[ID=二十五]] [[ID=二十六]]

Patent Document 1

[0005] This invention provides a technology for efficiently using frequency resources in a communication system that uses a communication link composed of multiple channels. [Means for solving the problem]

[0006] A communication device according to one aspect of the present invention is a communication device capable of communicating with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, wherein in the first frequency band of the first bandwidth used by the communication device for communication, there exists a second frequency band determined based on a second bandwidth that the other communication device can handle, and a third frequency band other than the second frequency band, and in frequency division multiplexing communication performed by the communication device with a plurality of devices including the other communication device, when the frequency resources of the second frequency band are allocated to a device other than the other communication device, the other communication device uses a fourth frequency band of the second bandwidth that includes the second frequency band and a part of the third frequency band. The system includes an acquisition means for acquiring capability information from the other communication device indicating whether or not it has the capability to perform the frequency division multiplexing communication by changing several frequency bands, and a communication means for allocating frequency resources to the other communication device and communicating with the other communication device, wherein the communication means allocates frequency resources to the other communication device from the second frequency band without changing the frequency band used by the other communication device, based on the fact that the other communication device does not have the predetermined capability, and allocates frequency resources to the other communication device from the second frequency band, or from the fourth frequency band by changing the frequency band used by the other communication device to the fourth frequency band, based on the fact that the other communication device has the predetermined capability. [Effects of the Invention]

[0007] According to the present invention, frequency resources can be used efficiently in a communication system that uses a communication link composed of multiple channels. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing an example configuration of a wireless communication system. [Figure 2] This is a schematic diagram showing an example of a time chart for when a communication device transmits data. [Figure 3] This is a schematic diagram showing an example of a communication time chart using DSO. [Figure 4] This figure shows an example of the hardware configuration of a communication device. [Figure 5] This figure shows an example of the AP's functional configuration. [Figure 6] This figure shows an example of the functional configuration of STA. [Figure 7] This figure shows an example of the sequence of events that occur when a communication device establishes a connection. [Figure 8] This figure shows an example of the configuration of the UHR Capabilities element. [Figure 9] This figure shows an example of a time chart for data communication in the downlink direction. [Figure 10] This figure shows an example of a processing flow executed by the AP. [Figure 11] This figure shows an example of the processing flow executed by STA. [Figure 12] This figure shows an example of a time chart for data communication in the uplink direction. [Figure 13] This figure shows an example of a processing flow executed by the AP. [Figure 14] This figure shows an example of the processing flow executed by STA. [Figure 15] This figure shows an example of the configuration of the User Info field. [Figure 16]This figure shows an example of the mapping between the settings in the User Info field and the assigned RU. [Figure 17] This figure shows an example of the RU (Ruler Unit) arrangement and the RU index associated with each RU in OFDMA communication. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0010] (System Configuration) Figure 1 shows an example configuration of a wireless communication system according to this embodiment. The wireless communication system includes, for example, an access point (AP) 101 and stations (STA) 111 and STA112. STA111 and STA112 are sometimes referred to as STA110 without distinction. Similarly, AP101 and STA110 are sometimes referred to as communication device 100 without distinction. AP101 and STA110 are communication devices capable of performing wireless communication compliant with the IEEE 802.11 standard series. IEEE is an abbreviation for Institute of Electrical and Electronics Engineers. Figure 1 shows a configuration in which STA111 and STA112 participate in a network 121 established by AP101. Network 121 may also be called a Basic Service Set (BSS). While Figure 1 shows a configuration with one AP101 and two STA110s in network 121, there may be multiple AP101s, and one or more STA110s. Furthermore, at that time, each STA110 may be connected to one AP101, or one STA110 may be connected to multiple AP101s.

[0011] In this embodiment, the communication device 100 is configured to execute a communication method compliant with the IEEE 802.11bn standard. The IEEE 802.11bn standard is the successor to the IEEE 802.11be standard, which aims for a maximum transmission speed of 46.08 Gbps (Gigabit per second). The main features of the IEEE 802.11bn standard are that it has functions that realize highly reliable communication, low latency communication, and improved throughput when communication traffic is congested. The wireless frame used in the communication method compliant with this standard may be called UHR (Ultra High Reliability) PPDU. PPDU is an abbreviation for PLCP Protocol Data Unit, and PLCP is an abbreviation for Physical Layer Convergence Protocol. Note that the names UHR and IEEE 802.11bn may be changed to other names when the standard is finalized. Furthermore, it should be noted that this specification and the claims attached herein are applicable to communication devices using all successor standards to IEEE 802.11be. Also, the communication device 100 may support at least one of the legacy standards that precede the IEEE 802.11bn standard. Legacy standards include, for example, the IEEE 802.11a / b / g / n / ac / ax / be standards. The communication device 100 may also support other communication standards such as Bluetooth®, NFC, UWB, ZigBee, and MBOA. UWB stands for Ultra Wide Band, and MBOA stands for Multi Band OFDM Alliance. NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, WiNET, etc. The communication device 100 may also support communication standards such as wired LAN. AP101 is, for example, a wireless LAN router or a personal computer (PC), but is not limited to these. AP101 may be an information processing device such as a wireless chip capable of performing wireless communication compliant with the IEEE 802.11bn standard, etc.STA110 is, for example, a wearable device such as a camera, tablet, smartphone, PC, mobile phone, video camera, headset, smart glasses, HMD (head-mounted display), etc., but is not limited thereto. STA110 may be an information processing device such as a wireless chip capable of performing wireless communication that supports transmission and reception of PPDU compliant with IEEE802.11bn standard or the like. In this case, various controls can be executed by a hardware circuit inside the wireless chip. Note that various processes can also be executed by cooperation of a processor such as ASIP, memory, and hardware circuit inside the wireless chip. ASIP is an abbreviation of Application-specific instruction set processor.

[0012] The communication device 100 can communicate using radio signals in frequency bands such as the 2.4GHz, 3.6GHz, 5GHz, 6GHz bands, and millimeter wave bands such as the 45GHz and 60GHz bands. The frequency bands used by the communication device 100 are not limited to these, and may include, for example, the Sub1GHz band. Furthermore, the communication device 100 can communicate using bandwidths of 20MHz, 40MHz, 80MHz, 160MHz, 320MHz, 540MHz, 640MHz, 1080MHz, and 2160MHz. The bandwidths used by the communication device 100 are not limited to these, and may include, for example, 240MHz or 4MHz. Note that the IEEE 802.11 standard series specifies frequency channels using a 20MHz bandwidth as basic channels in frequency bands such as the 2.4GHz, 5GHz, and 6GHz bands. In addition, this standard defines multiple usable channels in each of the 2.4GHz, 5GHz, and 6GHz frequency bands. In this standard, the communication device 100 may use one channel in combination with other adjacent channels. This use of one channel in combination with other adjacent channels may be called channel bonding. A bundle of channels formed by one or two or more adjacent channels may be called a communication link. That is, one link formed by two channels with a bandwidth of 20 MHz may use a bandwidth of 40 MHz. The IEEE 802.11be standard and its successor standards (including the IEEE 802.11bn standard and its successor standards) are expected to specify a maximum bandwidth of 320 MHz or more as the maximum bandwidth available in a single link. For example, a link using a bandwidth of 320 MHz may be formed by bundling 16 channels with a bandwidth of 20 MHz using channel bonding. The signals transmitted in this bandwidth may be continuous or discontinuous on the frequency axis. AP101 and STA110 may be AP MLD (Multi-Link Device) and STA MLD, respectively, that support Multi-Link, enabling communication by establishing multiple links simultaneously.

[0013] The communication device 100 establishes one or more links between devices in order to communicate data with other communication devices. For example, the STA 110 executes a connection procedure with the AP 101 to establish a link with the AP 101. The connection procedure includes, for example, the transmission of a connection request by the STA 110 and the transmission of a connection response by the AP 101. When the connection procedure is completed, a link is established between the STA 110 and the AP 101. The establishment of a link is sometimes referred to as the establishment of a connection. By establishing a link, the communication device 100 can access the wireless medium and communicate data and the like with the other communication device. For example, when one link using a bandwidth of 320 MHz is established between devices, the communication device 100 can perform communication by channel bonding using available channels according to the channel status among all or some of the channels constituting the link.

[0014] When the communication device 100 transmits a signal using a link established with another communication device, it performs carrier sensing to determine whether or not to transmit. Carrier sensing is the operation in which the communication device 100 determines whether or not there is a signal on the channel that it intends to use for transmission. For example, the communication device 100 measures the strength of the signal received on the channel (received signal strength) and determines that a signal exists if the received signal strength exceeds a predetermined threshold (physical carrier sensing). The received signal strength may also be called the Received Signal Strength Indicator (RSSI). The communication device 100 may also determine the presence or absence of a signal based on information such as the Duration field contained in the signal received on the channel (virtual carrier sensing). For example, the communication device 100 stores the period indicated by the Duration field contained in the received signal as a Network Allocation Vector (NAV) within itself. The communication device 100 can treat the stored NAV as a period during which it does not transmit. In this embodiment, the operation by which the communication device 100 sets a period during which it does not transmit based on information such as the Duration field of the received signal is called setting NAV. That is, until the NAV set for the channel expires, the communication device 100 determines that a signal is present on the channel. In this way, the communication device 100 determines whether or not a signal is present on the channel based on the results of performing physical carrier sensing and virtual carrier sensing. If the communication device 100 determines that a signal is present on the channel, it may determine that the channel is in a state where transmission is not possible. In this case, the state of the channel may be called a busy state. On the other hand, a state in which no signal is detected on the channel in carrier sensing and NAV is not set may be called an idle state. If the communication device 100 is in an idle state, it may determine that the channel is in a state where transmission is possible.

[0015] When communication is performed using a link with a predetermined bandwidth, the communication device 100 may determine whether transmission is possible using only the Primary Channel (PCH) with a bandwidth of 20 MHz included in that link. For example, the PCH is one of 16 channels with a bandwidth of 20 MHz that make up a link with a bandwidth of 320 MHz. In this case, the communication device 100 may determine that transmission is impossible based on the PCH being busy, or that transmission is possible based on the PCH being idle. Therefore, if the communication device 100 determines that transmission is impossible as a result of carrier sensing on the PCH, it may postpone transmission even if other channels included in the same link are idle. Note that each channel other than the PCH that makes up a single link may be called a secondary channel (SCH). Secondary channels may also be called non-primary channels (NPCH).

[0016] The IEEE 802.11 standard series specifies a function that increases communication speed by enabling multi-user (MU) communication, where the AP101 multiplexes wireless resources to communicate simultaneously with multiple STA110s. For example, the AP101 can communicate in parallel with multiple STA110s using OFDMA. OFDMA is an abbreviation for Orthogonal Frequency Division Multiple Access. In OFDMA, multiple units are formed on the frequency axis in a PPDU transmitted using a frequency channel of a predetermined bandwidth. Each of these units is called a Resource Unit (RU). The AP101 assigns one or more different RUs to each STA110. Multi-user communication can be performed by the AP101 communicating in parallel with each STA110 using the RUs assigned to each STA110. The predetermined bandwidth can be 20MHz, 40MHz, 80MHz, 160MHz, 320MHz, etc. Also, each RU is composed of multiple subcarriers. For example, a RU composed of 26 subcarriers is called a 26-tone RU. Based on the number of subcarriers that make up the RU, RUs can be composed of 26-tone, 52-tone, 106-tone, 242-tone, 484-tone, 996-tone, and so on.

[0017] Here, the usable frequency bandwidth of the communication device 100 may vary depending on the communication device 100. For example, suppose AP101 can use a bandwidth up to 320MHz, while STA111 and STA112 each have a usable bandwidth of up to 80MHz. In this case, according to the current IEEE 802.11 standard series, the frequency bandwidth used for communication between AP101 and each STA110 will be the 80MHz bandwidth including the PCH within the 320MHz frequency bandwidth used by the AP. The 80MHz channel including the PCH is called the Primary 80MHz Channel. Therefore, when AP101 performs OFDMA communication between STA111 and STA112, it will form multiple RUs in the 80MHz frequency bandwidth of the primary 80MHz channel and assign the RUs to each STA110. Figure 2 shows an example sequence when AP101 performs OFDMA communication between STA111 and STA112 on the primary 80MHz channel. At time t0, AP101 begins transmitting PPDUs to STA111 and STA112, respectively. At time t1, STA111 and STA112 each begin transmitting PPDUs to AP101. Furthermore, at time t2, AP101 begins transmitting PPDUs to STA111 and STA112, respectively. In all cases, communication takes place using the 80MHz frequency band including the PCH (primary 80MHz channel), and the RU used between AP101 and each STA110 is a part of this 80MHz frequency band. Thus, even if AP101 can use a 320MHz bandwidth, if the bandwidth available to each STA110 is 80MHz, the frequency band used between AP101 and the multiple STA110s is limited to the primary 80MHz channel. As a result, there are unused frequency resources within the frequency band that AP101 can use, and these unused frequency resources become larger the greater the difference between the bandwidth that AP101 can use and the bandwidth that STA110 can use.For example, in Figure 2, the 240MHz bandwidth will not be used.

[0018] In light of these circumstances, AP101 in this embodiment allocates frequency resources in frequency division multiplexing communication with multiple STA110s based on whether or not it has the ability to change the frequency band used by the STA110s for communication. For example, suppose that in the first frequency band of the first bandwidth used by AP101 for communication, there is a second frequency band determined based on the second bandwidth that the STA110s can handle, and a third frequency band other than the second frequency band. For example, in the example in Figure 2, the first bandwidth is 320 MHz and the second bandwidth is 80 MHz. The first frequency band is the 320 MHz frequency band usable by AP101, the second frequency band is the 80 MHz frequency band usable by STA111 and STA112, and the third frequency band is the unused 240 MHz frequency band. First, AP101 obtains capability information from STA110 indicating whether STA110 has the capability to change the frequency band used to perform frequency division multiplexing communication from the second frequency band to a fourth frequency band that includes a portion of the third frequency band. Based on the fact that STA110 does not have the capability, AP101 allocates frequency resources to STA110 from the second frequency band. Alternatively, based on the fact that STA110 has the capability, AP101 allocates frequency resources to STA110 from the second frequency band, or from the fourth frequency band after STA110 changes the frequency band it uses to the fourth frequency band. Meanwhile, STA110 notifies AP101 of the capability information indicating whether or not it has the capability. STA110 identifies the frequency resources in the second frequency band that were allocated to it based on the fact that its device does not have the capability. STA110 also identifies the frequency resources in the second or fourth frequency band that were allocated to it based on the fact that its device has the capability. If STA110 is allocated frequency resources within the fourth frequency band, it will change the frequency band it uses to the fourth frequency band. AP101 and STA110 will communicate using the frequency resources allocated to STA110.With this configuration, when STA110 is engaged in frequency division multiplexing communication with AP101, if the frequency resources of the second frequency band are allocated to an STA110 other than its own communication device, STA110 can change to the fourth frequency band and participate in frequency division multiplexing communication. By changing the frequency band used while maintaining the bandwidth used by STA110 in this way, AP101 can perform frequency division multiplexing communication using a wide bandwidth even if the corresponding bandwidth of each STA110 is narrow. An example of the configuration and processing of a communication device 100 that operates in this manner is described below.

[0019] (DSO Overview) First, an overview of the operation of Dynamic Subband Operation (DSO) performed by the communication device 100 of this embodiment will be described. Between AP101 and STA110, which are capable of performing DSO, multiple frequency domains are set within the frequency band used by AP101. The multiple frequency domains may be set so as not to overlap with each other, or they may be set to partially overlap. Each frequency domain may be explicitly set as a range on the frequency axis. Alternatively, each frequency domain may be implicitly set by setting either its lower or upper end, and the bandwidth available to STA110 based on that lower or upper end. The setting of each frequency domain is not limited to these, and it is sufficient to indicate the destination when changing the frequency band used by STA110. For example, each frequency domain may be indicated using the distance on the frequency axis or its relationship to the PCH, with the PCH as the reference. The relationship to the PCH may be indicated as Secondary 20MHz Channel, Secondary 40MHz Channel, Secondary 80MHz Channel, Secondary 160MHz Channel, etc. Furthermore, the relationship with the PCH may be indicated as Primary 20MHz Channel, Primary 40MHz Channel, Primary 80MHz Channel, Primary 160MHz Channel, etc. Each frequency domain may be called a segment, subblock, subband, etc. If there are two frequency domains to be set, the frequency domain including the PCH may be defined as the primary channel or primary band, and the frequency domain not including the PCH may be defined as the secondary channel or subband. Figure 3 shows an example where AP101, which uses a frequency band with a bandwidth of 320MHz, sets four frequency domains, from the first to the fourth, in relation to STA110, which can use a bandwidth of 80MHz. Each frequency domain may be set with the bandwidth available to STA110 as one unit. AP101 may also set frequency domains that are commonly used in the BSS that it configures. In this case, a bandwidth larger than the available bandwidth of STA110 may be set.For example, in Figure 3, two frequency domains with a bandwidth of 160 MHz may be set. In this case, the frequency band used by STA110 will be the frequency band of the bandwidth available to STA110 within each frequency domain. Each frequency domain may consist of different bandwidths. AP101 can set frequency domains according to the bandwidth available to STA110. For example, if the bandwidth available to STA110 is 20 MHz, AP101 can set up to eight frequency domains with a bandwidth of 40 MHz, up to four frequency domains with a bandwidth of 80 MHz, two frequency domains with a bandwidth of 160 MHz, etc.

[0020] STA110 communicates with AP101 while changing the frequency band it uses in response to notifications from AP101. Changing the frequency band used by STA110 can be described as moving along the frequency axis. For example, in Figure 3, suppose AP101 and STA110 are communicating data 301 in a first frequency domain including the PCH at times t0 to t1. At time t2, AP101 sends notification 302 to STA110 indicating that it should move to a third frequency domain. AP101 may explicitly notify STA110 to move to the third frequency domain, or it may implicitly notify STA110 using a frequency resource notification by specifying the frequency domain that contains the frequency resources to be allocated to STA110. In response to this notification 302, STA110 moves to the third frequency domain. Then, AP101 and STA110 communicate data 303 in the third frequency domain. In parallel with the communication of data 303, AP101 communicates with other STA110s in the first frequency domain using frequency division multiplexing. Once the communication of data 303 is complete, STA110 can return to the first frequency domain. In this way, by switching the frequency band used by STA110 in response to notifications from AP101, AP101 can communicate with STA110s while effectively utilizing the frequency resources in the frequency band available to its device.

[0021] Alternatively, instead of setting the frequency range as described above, a distance to be moved on the frequency axis to change the frequency band used by STA110 may be set. For example, in Figure 3, the lower end of the 320 MHz frequency band used by AP101 may be set as the first frequency, and second, third, and fourth frequencies may be set at 80 MHz intervals. In this case, STA110 may set the frequency band used by its own device to be one of the first to fourth frequencies, with the lower end being one of them, based on a notification from AP101. Each of the first to fourth frequencies may be called a frequency switching position.

[0022] (Device configuration) Figure 4 shows an example of the hardware configuration of the communication device 100 in this embodiment. As an example of its hardware configuration, the communication device 100 includes, for example, a storage unit 401, a control unit 402, a function unit 403, an input unit 404, an output unit 405, a communication unit 406, and an antenna 407. The communication device 100 may have multiple antennas.

[0023] The storage unit 401 is composed of one or more memories, including ROM and RAM, and may store control programs for various operations of each functional unit constituting the communication device 100, as well as various information such as parameters for communication. ROM and RAM are abbreviations for Read Only Memory and Random Access Memory, respectively. In addition to memories such as ROM and RAM, the storage unit 401 may also be composed of 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.

[0024] The control unit 402 is composed of one or more processors, such as a CPU and an MPU, and controls the entire communication device 100 by executing a control program stored in the memory unit 401. Alternatively, the control unit 402 may control the entire communication device 100 in cooperation with the OS (Operating System) and the control program stored in the memory unit 401. CPU and MPU are abbreviations for Central Processing Unit and Micro Processing Unit, respectively. If the control unit 402 has multiple processors, such as a multi-core processor, it may be configured so that the entire communication device 100 is controlled by multiple processors.

[0025] Furthermore, the control unit 402 controls the functional unit 403 to perform predetermined processes such as communication, imaging, printing, and projection. The functional unit 403 is hardware that enables the communication device 100 to perform the predetermined processes described above. For example, if the device is a camera, the functional unit 403 is the imaging unit and performs imaging processing. Also, for example, if the device is a printer, the functional unit 403 is the printing unit and performs printing processing. Also, for example, if the device is a projector, the functional unit 403 is the projection unit and performs projection processing.

[0026] The input unit 404 receives various operations from the user. The output unit 405 outputs various information to the user via a monitor screen or speaker. The output from the output unit 405 may be a display on the monitor screen, audio output via a speaker, vibration output, etc. The input unit 404 and the output unit 405 may both be implemented in a single module, such as a touch panel. The input unit 404 and the output unit 405 may each be an integrated device with the communication device 100, or they may be separate devices.

[0027] The communication unit 406 controls wireless communication compliant with the IEEE 802.11bn standard. In addition to the IEEE 802.11bn standard, the communication unit 406 may also control wireless communication compliant with other IEEE 802.11 standard series, such as legacy standards. The communication unit 406 controls the antenna 407 to transmit and receive signals for wireless communication generated by the control unit 402. The communication unit 406 is a so-called wireless chip and may itself include one or more processors and memory. If the communication device 100 supports other wireless communication standards such as NFC and Bluetooth, or wired communication such as wired LAN, in addition to the IEEE 802.11bn standard, the communication unit 406 may control communication compliant with these communication standards. Furthermore, if the communication device 100 can perform wireless communication compliant with multiple communication standards, the communication device 100 may have separate communication units and antennas corresponding to each communication standard. The communication device 100 communicates data with the other communication device via the communication unit 406. The antenna 407 may be configured separately from the communication unit 406, or it may be configured together with the communication unit 406 as a single module.

[0028] Antenna 407 is an antenna capable of communication in the 2.4GHz band, 5GHz band, 6GHz band, and millimeter wave bands such as 45GHz and 60GHz. Figure 4 shows a configuration in which the communication device 100 has two antennas 407, but the communication device 100 may have one or more antennas, or one or more antennas for each frequency band that the device can use. Furthermore, if the communication device 100 has multiple antennas, the communication device 100 may have a communication unit 406 for each antenna.

[0029] (Functional Configuration) Figure 5 shows an example of the functional configuration of AP101. The functional configuration in this embodiment is an example of a functional configuration realized by, for example, one or more processors executing programs stored in one or more memories. AP101 may be configured to include a wireless communication control unit 501, an information acquisition unit 502, a resource allocation unit 503, and a DSO control unit 504.

[0030] The wireless communication control unit 501 controls communication with the STA110. For example, the wireless communication control unit 501 can send and receive frames necessary for performing OFDMA communication with the STA110. As an example, the wireless communication control unit 501 can send UHR MU PPDUs and trigger frames, and receive UHR TB PPDUs. The wireless communication control unit 501 can adjust the length of the transmitted frames based on the time required for the STA110 to move on the frequency axis when performing DSO.

[0031] The information acquisition unit 502 acquires information about the STA110. For example, the information acquisition unit 502 may acquire information that determines whether or not the STA110 has the capability to perform communication using a DSO. The information acquisition unit 502 may also acquire information indicating the distance that the STA110 can travel on the frequency axis when performing communication using a DSO. Furthermore, the information acquisition unit 502 may acquire information indicating the time required for the STA110 to travel on the frequency axis. The information acquired by the information acquisition unit 502 can be used by the resource allocation unit 503 and the DSO control unit 504.

[0032] The resource allocation unit 503 performs the allocation of frequency resources to the STA110. For example, when the wireless communication control unit 501 communicates with the STA110 using OFDMA, the resource allocation unit 503 may select a frequency range to allocate frequency resources based on whether or not the STA110 has the capability to perform DSO. Alternatively, the resource allocation unit 503 may select a frequency range to allocate frequency resources to the STA110 based on the distance the STA110 can move along the frequency axis. The resource allocation unit 503 allocates the frequency resources included in the selected frequency range to the STA110. If the resource allocation unit 503 allocates frequency resources from a frequency range other than the first frequency range to the STA110, it may notify the STA110 that it should move along the frequency axis.

[0033] The DSO control unit 504 controls the communication using DSO with the STA110. For example, the DSO control unit 504 decides whether or not to perform DSO communication with the STA110 based on whether or not the STA110 has the capability to perform DSO. The DSO control unit 504 may also decide whether or not to perform DSO communication with the STA110 based on the distance the STA110 can move on the frequency axis and the time required to move. The DSO control unit 504 may set multiple frequency ranges or one or more frequency switching positions as destinations for changing the frequency band used by the STA110.

[0034] Figure 6 shows an example of the functional configuration of STA110. The functional configuration in this embodiment is an example of a functional configuration realized by, for example, one or more processors executing programs stored in one or more memories. STA110 may be configured to include a wireless communication control unit 601, an information notification unit 602, an information acquisition unit 603, and a frequency band control unit 604.

[0035] The wireless communication control unit 601 controls communication with AP101. For example, the wireless communication control unit 501 can send and receive frames necessary for performing OFDMA communication with AP101. As an example, the wireless communication control unit 501 can receive UHR MU PPDU and Trigger frames and send UHR TB PPDUs. The wireless communication control unit 601 communicates with AP101 using the frequency resources allocated to its own device.

[0036] The information notification unit 602 notifies AP101 of information relating to its own device. For example, the information notification unit 602 may notify AP101 of information indicating whether or not its own device has the capability to perform communication using a DSO. In addition, the information notification unit 602 may notify AP101 of information indicating the distance that its own device can travel on the frequency axis when performing communication using a DSO. Furthermore, the information notification unit 602 may notify AP101 of information indicating the time required for its own device to travel on the frequency axis.

[0037] The information acquisition unit 603 acquires information from AP101. The information acquisition unit 603 may acquire information that identifies whether AP101 has the capability to perform communication using DSO. The information acquisition unit 603 may also acquire information that identifies the delay time that AP101 allows in communication using DSO. Furthermore, the information acquisition unit 603 may acquire information that identifies the frequency resources allocated to its own device. The information identifying the frequency resources acquired by the information acquisition unit 603 can be used by the wireless communication control unit 601, the frequency band control unit 604, etc.

[0038] The frequency band control unit 604 controls the frequency band used by the device. For example, under normal circumstances, the frequency band control unit 604 sets the first frequency domain, which includes the PCH, as the frequency band used by the device. If the frequency resources allocated to the device are included in a frequency domain other than the first frequency domain, the frequency band control unit 604 sets the frequency domain containing those frequency resources as the frequency band used by the device. Furthermore, when communication in that frequency band ends, the frequency band control unit 604 returns the used frequency band to the first frequency domain. In addition, if the frequency band control unit 604 is notified by AP101 to move along the frequency axis, it may change the frequency band used in accordance with that notification.

[0039] (Process flow) Below, we will describe some examples of the processing flow performed by AP101 and each STA in this embodiment.

[0040] (Sharing of capability information for performing communications using DSO) AP101 and STA110 can share information about their respective communication devices' ability to perform DSOs when establishing a connection between them. The operations performed by each communication device when a connection is established between AP101 and STA110 are explained using Figure 7. Figure 7 shows an example sequence of processes performed when a connection is established between AP101 and STA110. This sequence may be performed, for example, when the STA110 is powered on and the connection with AP101 is initiated. First, AP101 periodically transmits Beacon frames (F701). The Beacon frames may include AP101's capability information and communication parameters to be used in the BSS configured by AP101. Capability information may be called Capabilities information. Communication parameters may be called Operation information. The BSS configured by AP101 is sometimes called its own BSS. For example, AP101 may transmit its own device capability information, such as the frequency bandwidth available to it and its ability to perform DSOs, via Beacon frames. Furthermore, AP101 can transmit information in a Beacon frame that identifies the frequency band and PCH used by its BSS as communication parameters, and information that identifies whether DSO is enabled or disabled. STA110 receives the Beacon frame transmitted from AP101. Using the received Beacon frame, STA110 can identify the frequency band and PCH used by AP101, and determine whether AP101 has the capability to use DSO, whether DSO is enabled, etc.

[0041] STA110 initiates the connection procedure by sending a Probe Request frame to AP101 based on the information obtained from the Beacon frame (F702). The Probe Request frame may contain STA110's capability information and communication parameters. For example, STA110 may send information in the Probe Request frame indicating its own capability information, such as the frequency bandwidth it can use, whether it has the capability to perform DSO, and whether it has enabled or disabled DSO. For example, STA110 may notify AP101 that it has the capability to perform DSO using the UHR Capabilities element and UHR Operation element included in the Association Request frame. Note that if AP101 does not send a Beacon, or if STA110 cannot properly receive the Beacon sent by AP101, STA110 may initiate the connection procedure without receiving a Beacon. For example, STA110 may initiate the connection procedure by sending a Probe Request frame using an SSID (Service Set Identifier) ​​that has been registered in advance by the user.

[0042] When AP101 receives a Probe Request frame, it sends a Probe Response frame (F703). In the Probe Response frame, AP101 may notify STA110 of its own device capability information and communication parameters to be used in its BSS. AP101 and STA110 authenticate each other's communication devices by exchanging Authentication frames (F704).

[0043] Once STA110 has completed authentication of the other party's communication device, it sends an Association Request frame (F705). STA110 may also use the Association Request frame to notify AP101 of its own device capabilities and communication parameters. Upon receiving the Association Request frame, AP101 sends an Association Response frame (F706). AP101 may also use the Association Response frame to notify STA110 of its own device capabilities and its BSS communication parameters. Upon receiving the Association Response frame from AP101, STA110 establishes a connection between AP101 and STA110, and the connection procedure is completed. AP101 and STA110 may then perform a 4-way Handshake to share security information.

[0044] AP101 and STA110 can exchange information for executing DSO during the connection procedure. For example, AP101 and STA110 can notify each other of information indicating whether their own device has the capability to execute DSO, and can obtain information indicating whether the other communication device has the capability to execute DSO. Based on the fact that STA110 has the capability to execute DSO, AP101 can allocate frequency resources to STA110 that are included in frequency domains other than the first frequency domain set between AP101 and STA110. Based on the fact that AP101 has the capability to execute DSO, STA110 can start exchanging information necessary for executing DSO between its own device and AP101. AP101 and STA110 can notify each other of information indicating whether their own device has enabled or disabled the function to execute DSO, and can obtain information indicating whether the other communication device has enabled or disabled the function to execute DSO. Each communication device 100 may disable the DSO function due to interference in the surroundings, etc., even if its own device has the capability to execute DSO. By exchanging information indicating whether or not the DSO function is enabled, it becomes possible to determine whether the communication device of one device and the other device are in a state where DSO can be executed. AP101 and STA110 may also determine that the other device does not have the capability to execute DSO if the frame received from the other device does not contain a UHR Capabilities element. This makes it possible to notify the other device of whether or not it has the capability to execute DSO without having to include a field in the UHR Capabilities element to indicate whether or not it has the capability to execute DSO.

[0045] AP101 and STA110 can exchange information indicating the distance STA110 can travel on the frequency axis when performing DSO. This allows AP101 and STA110 to set multiple frequency domains within the frequency band used by AP101. For example, AP101 can set multiple frequency domains within the range usable by STA110 within the frequency band used by its own device by obtaining the bandwidth available to STA110. For example, if AP101 is using a frequency band with a bandwidth of 320 MHz and the available bandwidth of STA110 is 80 MHz, AP101 can set four frequency domains, from the first to the fourth. In this case, if the distance STA110 can travel on the frequency axis is 80 MHz, STA110 cannot use the third and fourth frequency domains. In this case, AP101 sets two frequency domains with a bandwidth of 80 MHz between itself and STA110. In this way, by sharing information between AP101 and STA110 that indicates the distance STA110 can move on the frequency axis when performing DSO, it becomes possible to set the frequency range that can be set as the frequency band used by STA110.

[0046] Furthermore, AP101 and STA110 can exchange information indicating the time required for STA110 to move along the frequency axis when performing DSO. The time required for STA110 to move along the frequency axis when performing DSO may be called frequency switching delay. As a result, AP101 may determine that it will not perform DSO with STA110 if STA110's frequency switching delay exceeds the time that AP101 can tolerate for DSO to be performed. AP101 may also perform control to assist STA110's DSO if STA110's frequency switching delay exceeds a predetermined time. The predetermined time may be a time defined by standards such as Short Interframe Space (SIFS). For example, AP101 may adjust the length of the frame it transmits as control to assist STA110's DSO. For example, AP101 may use STA110's frequency switching delay to determine the length of the frame when performing DSO. For example, AP101 may add padding corresponding to the frequency switching delay of STA110 in a frame that notifies STA110 to move to another frequency domain. Padding may be pseudo-data to adjust the length of the frame. This may ensure that the time necessary for STA110 to move to the other frequency domain is secured. Note that the first frequency switching delay when STA110 moves from the first frequency domain to another frequency domain may differ from the second frequency switching delay when STA110 moves from another frequency domain to the first frequency domain. In this case, AP101 may obtain the first and second frequency switching delays from STA110. AP101 may then add padding according to the cases in which STA110 moves from the first frequency domain to another frequency domain and from another frequency domain to the first frequency domain. AP101 may also specify a frequency range in which at least one or both of the first frequency switching delay and the second frequency switching delay satisfy a predetermined threshold as the frequency range that STA110 can use for the DSO.Furthermore, if the frequency switching delay differs depending on the distance STA110 moves along the frequency axis, AP101 may acquire the frequency switching delay for each frequency domain. For example, AP101 may acquire the first frequency switching delay for STA110 to move to the second, third, and fourth frequency domains, respectively, with respect to the first frequency domain. It may also acquire the second frequency switching delay for STA110 to move from the second, third, and fourth frequency domains back to the first frequency domain. In this case, AP101 may add padding to the frame that notifies STA110 to move to another frequency domain, according to the frequency switching delay corresponding to the frequency domain containing the frequency resources to be allocated to STA110.

[0047] AP101 can notify STA110 of the acceptable frequency switching delay for its own device when it is performing DSO. This acceptable time may be notified via a Beacon frame or the like. Upon receiving this acceptable time, STA110 can determine whether its own device's frequency switching delay exceeds AP101's acceptable time. Based on the finding that its own device's frequency switching delay exceeds AP101's acceptable time, STA110 can disable DSO. In this case, STA110 can notify AP101 that its device has disabled DSO. This allows AP101 and STA110 to skip the exchange of information necessary to perform DSO. Furthermore, if STA110's own frequency switching delay varies depending on the distance traveled on the frequency axis, STA110 can notify AP101 of the distance that can be traveled without exceeding AP101's acceptable time. This simplifies the exchange of information necessary to perform DSO between AP101 and STA110.

[0048] AP101 can notify STA110 of its own capabilities and communication parameters using Beacon frames, Probe Response frames, Association Response frames, etc. STA101 can notify AP101 of its own capabilities and communication parameters using Probe Request frames, Association Request frames, etc. AP101 and STA110 may voluntarily notify each other of their own capabilities, etc., or they may notify each other of their own capabilities, etc., based on a request from the other party's communication device. Furthermore, AP101 and STA110 may passively acquire capabilities information by waiting for notification of capabilities information from the other party's communication device, or they may actively acquire capabilities information by making a request to the other party's communication device. By broadcasting its own capabilities using Beacon frames, AP101 can efficiently notify an unspecified number of STA110s of its capabilities. In addition, by STA110 acquiring AP101's capabilities information before starting the connection procedure with STA110, the amount of information exchanged during the connection procedure can be reduced. In addition, FILS Discovery frames may be used instead of Beacon frames. FILS Discovery frames can be used to broadcast only a portion of the information contained in Beacon frames (such as SSID and channel information).

[0049] (Configuration of information on the ability to perform DSO) This section describes the structure of the information used by the communication device 100 when it notifies the other party's communication device of its own DSO capability information. Figure 8 shows an example of the structure of the information elements used by the communication device 100 when it notifies the other party's communication device of its own DSO capability information. The information elements may be called Information Elements (IE). The information elements in Figure 8 may be called UHR Capabilities elements. UHR Capabilities elements may be included in Beacon frames, Probe Response frames, Association Response frames, etc. Also, UHR Capabilities elements may be included in Probe Request frames, Association Request frames, etc. UHR Capabilities elements may also be included in frames other than these. For example, UHR Capabilities elements may be included in Action frames. This makes it possible to change values ​​such as frequency switching delay depending on the surrounding conditions, for example, after the connection between AP101 and STA110 is established.

[0050] The UHR Capabilities element includes the Element ID field 801, the Length field 802, and the Element ID Extension field 803. The UHR Capabilities element may also include the DSO Transmit Capable (DTC) field 804 and the DSO Receive Capable (DRC) field 805. Furthermore, the UHR Capabilities element may include the DSO padding delay field 806, the DSO Transition Delay field 807, and the DSO Subbandwidth field 808. Additionally, the UHR Capabilities element may include the DSO Padding Timeout field 809 and the DSO Transition Timeout field 810.

[0051] The combination of the Element ID field 801 and the Element ID Extension field 803 indicates the type of information element. For example, if the Element ID field 801 is set to 255 and the Element ID Extension field 803 is set to 138, it indicates that this information element is a UHR Capabilities element. The Length field 802 indicates the length of this information element. The DTC field 804 indicates whether the communication device 100 has the capability to perform transmission processing in the DSO. Alternatively, the DSO UL Capable field may be included instead of the DTC field 804. The DSO UL Capable field indicates whether the communication device 100 has the capability to perform uplink data processing in the DSO. The DRC field 805 indicates whether the communication device 100 has the capability to perform reception processing in the DSO. Alternatively, the DSO DL Capable field may be included instead of the DRC field 805. The DSO DL Capable field indicates whether the communication device 100 has the capability to perform downlink data processing in the DSO. Furthermore, the DTC field 804 and the DRC field 805 may be configured as a single field. In this case, this single field indicates whether or not the communication device 100 has the capability to perform DSO. If a value of 1 is set in these fields, it indicates that the communication device 100 has the capability to perform DSO, and if a value of 0 is set, it may indicate that the communication device 100 does not have the capability to perform DSO. In addition, the communication device 100 may implicitly indicate that it is capable of performing DSO by transmitting a frame that includes the UHR Capabilities element. In this case, if the bandwidth available to the STA 110 is smaller than the bandwidth of the frequency band used by the AP 101, the STA 110 may be interpreted as being capable of DSO operation. For example, if the bandwidth of the frequency band used by the AP 101 is 320 MHz, the communication device 100, which operates with a bandwidth up to 160 MHz, may be interpreted as being capable of performing DSO.Furthermore, the UHR Capabilities element may include a field indicating whether the communication device 100 has enabled or disabled the DSO, in addition to the DTC field 804 and the DRC field 805. This field may also be included in an information element other than the UHR Capabilities element. For example, this field may be included in the UHR Operation element.

[0052] The DSO padding delay field 806 to the DSO subbandwidth field 808 may be included in the frame transmitted by STA110. Additionally, the DSO Padding Timeout field 809 and the DSO Transition Timeout field 810 may be included in the frame transmitted by AP101. If the frame transmitted by AP101 includes the DSO padding delay field 806 to the DSO subbandwidth field 808, these fields may be treated as reserved areas. Similarly, if the frame transmitted by STA110 includes the DSO Padding Timeout field 809 and the DSO Transition Timeout field 810, these fields may also be treated as reserved areas. These fields may also exist if a value of 1 is set in the DTC field 804 or the DRC field 805, i.e., if the communication device 100 has the capability to perform DSO.

[0053] The DSO padding delay field 806 indicates the time required for STA110 to move along the frequency axis when performing DSO (frequency switching delay). For example, the DSO padding delay field 806 may indicate a first frequency switching delay required for STA110 to move from one frequency domain to another. The first frequency switching delay may be the time required for STA110 from the completion of receiving the User Info field assigned to its device in the Trigger frame described later until it becomes ready to communicate in the other frequency domain. An example configuration of the DSO padding delay field 806 is shown in Table 1. Table 1 shows the values ​​set in the DSO padding delay field 806 and the corresponding times when the DSO padding delay field 806 is composed of 3 bits. For example, if the UHR Capabilities element received by STA110 contains the DSO padding delay field 806, AP101 can determine the first frequency switching delay of STA110 based on Table 1. Furthermore, if the first frequency switching delay differs depending on the distance the STA110 moves along the frequency axis, a DSO padding delay field 806 corresponding to each distance may be provided.

[0054] Table 1 TIFF2026058976000002.tif78161

[0055] The DSO Transition delay field 807 indicates the time required for STA110 to move along the frequency axis when performing DSO (frequency switching delay). For example, the DSO Transition delay field 807 may indicate a second frequency switching delay required for STA110 to move from another frequency domain to a first frequency domain. An example configuration of the DSO Transition delay field 807 is shown in Table 2. Table 2 shows the values ​​set in the DSO Transition delay field 807 and the corresponding times when the DSO Transition delay field 807 is configured with 3 bits. For example, if the UHR Capabilities element received by STA110 contains the DSO Transition delay field 807, AP101 can identify the second frequency switching delay of STA110 based on Table 2. Note that if the second frequency switching delay differs depending on the distance STA110 moves along the frequency axis, a DSO Transition delay field 807 corresponding to each distance may be provided.

[0056] Table 2 TIFF2026058976000003.tif78163

[0057] The DSO Subbandwidth field 808 indicates the travelable distance that STA110 can move on the frequency axis when performing DSO. The travelable distance may be the distance that STA110 can move on the frequency axis when moving from a state where it is communicating in a predetermined frequency band to a state where it is communicating in a different frequency band. Alternatively, the travelable distance may be the distance that STA110 can move on the frequency axis to change the frequency band used by STA110 within the allowable time range for AP101 to perform DSO. An example configuration of the DSO Subbandwidth field 808 is shown in Table 3. Table 3 shows the values ​​set in the DSO Subbandwidth field 808 and the frequencies corresponding to those values ​​when the DSO Subbandwidth field 808 is configured with 3 bits. For example, if AP101 receives a UHR Capabilities element from STA110 that includes the DSO Subbandwidth field 808, it can determine the travelable distance of STA110 based on Table 3. For example, suppose the DSO Subbandwidth field 808 is set to a value of 3, and the usable frequency bandwidth for STA110 is set to 80 MHz. In this case, it may be shown that STA110 can switch between frequency ranges used within the range of 80 MHz, from a first frequency domain of the 80 MHz bandwidth. For example, it may be shown that STA110 can use the first frequency domain to the second frequency domain of the 80 MHz bandwidth in Figure 3. The movable distance may also indicate the frequency bandwidth that STA110 becomes usable by performing DSO. For example, suppose it is shown that the usable bandwidth for STA110 is 80 MHz, and that a bandwidth of 160 MHz becomes usable when the DSO Subbandwidth field 808 is set to a value of 4. This indicates that STA110, which can use an 80 MHz bandwidth, has expanded the range of bandwidth that this STA110 can use for communication to 160 MHz as a result of being able to move within the 80 MHz bandwidth by DSO.

[0058] The DTC field 804, DRC field 805, and DSO Subbandwidth field 808 may be configured as a single field. In this case, if a value of 0 is set in this field, it may indicate that the communication device 100 cannot perform DSO. Conversely, if a value other than 0 is set in this field, it may indicate that the communication device 100 can perform DSO. On the other hand, if the DSO Subbandwidth field 808 is configured independently of the DTC field 804, etc., a value of 0 in the DSO Subbandwidth field may be associated with a DSO Subbandwidth of 20 MHz. In this case, the DSO Subbandwidth corresponding to each value in the DSO Subbandwidth field is incremented. For example, a value of 1 in the DSO Subbandwidth field is associated with a DSO Subbandwidth of 40 MHz.

[0059] Table 3 TIFF2026058976000004.tif78163

[0060] The DSO Padding Timeout field 809 indicates the allowable time for the frequency switching delay of STA110 when AP101 performs DSO. For example, the DSO Padding Timeout field 809 may indicate the allowable time for the first frequency switching delay required for STA110 to move from one frequency domain to another. An example configuration of the DSO Padding Timeout field 809 is shown in Table 4. Table 4 shows the values ​​set in the DSO Padding Timeout field 809 and the corresponding times when the DSO Padding Timeout field 809 is configured with 4 bits. For example, if the STA110 receives a UHR Capabilities element from AP101 that includes the DSO Padding Timeout field 809, it can determine the allowable time for the first frequency switching delay based on Table 4. Note that if the allowable time for the first frequency switching delay differs depending on the distance STA110 moves along the frequency axis, separate DSO Padding Timeout fields 809 corresponding to each distance may be provided.

[0061] Table 4 TIFF2026058976000005.tif118163

[0062] The DSO Transition Timeout field 810 indicates the allowable time for the frequency switching delay of STA110 when AP101 performs DSO. For example, the DSO Transition Timeout field 810 may indicate the allowable time for a second frequency switching delay required for STA110 to move from another frequency domain to a first frequency domain. The DSO Transition Timeout field 810, like the DSO Padding Timeout field 809, may be configured as shown, for example, in Table 4.

[0063] Note that the mapping of values ​​in Tables 1 to 4 above is just an example, and the mappings can be different. For example, Tables 1 to 4 show an example where the corresponding value increases exponentially for each increase of 1 in the field value, but the corresponding value can be set to increase by the same amount for each increase of 1 in the field value. For example, in Table 1, the value of the DSO Padding Delay field 806 may increase by 16 μsec each time. Also, in Tables 1, 2, and 4, different values ​​are mapped to the same value set in the field, but the same value may be mapped. For example, when the value of the DSO Padding Delay field in Table 1 is 1, 16 μsec may be mapped, similar to when the value of the DSO Padding Delay field in Table 2 is 1. Furthermore, Tables 1 to 3 show an example where each field consists of 3 bits, but each field may consist of 1, 2, 4 or more bits. Similarly, Table 4 shows an example where the field consists of 4 bits, but the field may consist of 1 to 3, 5 or more bits. Furthermore, the DSO Paddin Delay field 806 and the DSO Transition Delay field 807 may be configured as a single field. Similarly, the DSO Paddin Timeout field 808 and the DSO Transition Timeout field 810 may be configured as a single field. For example, if the first frequency switching delay and the second frequency switching delay are of similar magnitude, configuring these fields as a single field can reduce the amount of information communicated.

[0064] Fields other than those included in Figure 8 may be included in the UHR Capabilities element. For example, a predetermined field may be included that indicates information for identifying each frequency domain to be set in the frequency band used by AP101. For example, STA110 may use this predetermined field to notify AP101 of information indicating the number of frequency domains to be set in the frequency band used by AP, or information indicating the number of frequency switching positions. For example, if the number of frequency domains is indicated by this predetermined field, the same number of frequency domains with the same bandwidth as the bandwidth available to STA110 may be set. Also, if the number of frequency domains is indicated by this predetermined field, the number of frequency domains indicated by this predetermined field may be set in the frequency band used by AP101. In this case, the bandwidth of each frequency domain can be determined by dividing the bandwidth of the frequency band used by AP101 by the number of frequency domains to be set. Also, if the number of frequency switching positions is indicated by this predetermined field, the number of frequency switching positions indicated by this predetermined field may be set for each bandwidth available to STA110 in the frequency band used by AP101. Furthermore, if the number of frequency switching positions is indicated by this predetermined field, each frequency switching position can be set at a position on the frequency axis obtained by dividing the frequency band used by AP101 by the number indicated by this predetermined field. AP101 can determine multiple frequency domains and frequency switching positions to be set in the frequency band used by its device based on the value of the predetermined field included in the frame received from STA110. AP101 can then notify STA110 of the result in the predetermined field in the frame transmitted by its device. AP101 may also unilaterally determine multiple frequency domains and frequency switching positions to be set in the frequency band used by its device and notify STA110 of them.

[0065] Figure 8 shows an example where the communication device 100 uses the UHR Capabilities element to notify the other communication device of its ability to perform DSO. However, this notification of capability information can be performed using other information elements. For example, the Extended Capabilities element can be used to extend the UHR Capabilities element, and the Multi-Link element can be used to notify information related to multi-link communication. In addition, a new element (such as a DSO element) may be defined for exchanging capability information related to the communication device's DSO. The communication device 100 may also add its ability to perform DSO to the UHR Operation element. This allows the communication device 100 to display a value corresponding to the change even when its ability to perform DSO is dynamically changed.

[0066] (Downstream data communication processing between AP and STA) This section describes the operation when data communication using DSO is performed between AP101 and STA110. Figure 9 shows an example sequence when downlink communication (downbound communication) is performed, in which AP101 sends data to STA110. OFDMA is assumed to be used in this communication. For example, AP101 sends data using UHR MU PPDU, which is compatible with OFDMA. UHR MU PPDU is an abbreviation for Ultra High Reliability Multi-user PPDU. In this example, AP101 and STA111 are in a state where they can perform communication using DSO, while STA112 is in a state where it cannot perform communication using DSO. In the connection between AP101 and STA111, it is assumed that two frequency domains for performing DSO are set in the frequency band used by AP101. For example, AP101 uses a frequency band with a bandwidth of 320 MHz, STA111 can use a bandwidth up to 80 MHz, and the first and second frequency domains each have a bandwidth of 160 MHz. In this case, STA111 can communicate with AP101 while moving between a frequency band with an 80MHz bandwidth included in the first frequency domain and a frequency band with an 80MHz bandwidth included in the second frequency domain. Alternatively, instead of explicitly setting two frequency domains, two frequency domains with a 160MHz bandwidth may be implicitly set by providing a single frequency switching position. In the connection between AP101 and STA112, no frequency domain or frequency switching position is set. AP101 also stores data destined for each STA110. To transmit this data, AP101 allocates frequency resources in the first frequency domain to STA112, which cannot use DSO, and allocates frequency resources in the second frequency domain to STA111, which can perform DSO.

[0067] First, AP101 sends a notification 901 to move STA111 to a second frequency domain prior to transmitting data. For example, AP101 may send a MU-RTS frame as notification 901. A MU-RTS frame is a type of trigger frame, and MU-RTS is an abbreviation for multi-user request to send. For example, AP101 sends a MU-RTS frame in the first frequency domain, which includes the PCH. This allows any STA110 connected to AP101 to receive the MU-RTS frame, regardless of whether DSO is running or not. The MU-RTS frame may contain User Info fields corresponding to STA111 and STA112, respectively. The User Info fields of the MU-RTS frame may contain information indicating the channel on which the corresponding STA110 should send a response. The User Info fields of the MU-RTS frame may also contain information indicating the frequency resources allocated to the corresponding STA110. This allows STA110 to identify the frequency resources assigned to its device and the frequency domain containing those resources before it begins receiving PPDUs. For example, AP101 may instruct STA111 to move to the second frequency domain by notifying STA111 of information indicating that a frequency resource in the second frequency domain has been assigned, using the User Info field corresponding to STA111. AP101 may also add padding 902 to the frame used for notification 901. The padding 902 may be added based on a first frequency switching delay for STA111 to move to the second frequency domain.

[0068] When STA111 receives notification 901, it moves to the second frequency domain on the frequency axis. For example, if notification 901 is a MU-RTS frame, STA111 identifies from the User Info field associated with its own device that frequency resources in the second frequency domain have been allocated to its own device, and determines that it should move to the second frequency domain. STA111 then sends a response 904 to notification 901 in the second frequency domain. For example, if notification 901 is a MU-RTS frame, STA111 sends a CTS frame as response 904. CTS is an abbreviation for clear to send. STA111 may also send a CTS frame if the time elapsed from the start of movement to the second frequency domain to the transmission of the CTS frame is less than or equal to the allowable time notified by AP101. In this case, STA111 starts moving to the second frequency domain and activates timer 903 once it has finished receiving the User Info field associated with its own device. Timer 903 can be set to expire within the allowable time notified by AP101. When STA111 transmits a CTS frame, it transmits the CTS frame if Timer 903 has not expired, and does not transmit the CTS frame if Timer 903 has expired. This prevents STA111 from transmitting a CTS frame when AP101 has exceeded the allowable time.

[0069] When STA112 receives notification 901, it sends a response 905 in the first frequency domain. For example, if notification 901 is a MU-RTS frame, STA112 sends a CTS frame as response 905.

[0070] When AP101 receives a response 904 or 905 to notification 901, it transmits data based on the received response. For example, based on receiving response 904 from STA111 in the second frequency domain, AP101 transmits data 906 in the second frequency domain. Also, based on receiving response 905 from STA112 in the first frequency domain, AP101 transmits data 907 in the first frequency domain. Note that if AP101 does not receive a response to notification 901, it does not transmit data. For example, if AP101 receives response 905 but not response 904, it transmits data 907 instead of data 906.

[0071] STA111 and STA112, upon receiving data 906 and 907 addressed to themselves, respectively, send acknowledgments 908 and 909 for that data. For example, STA111 and STA112 may send Block Ack frames as acknowledgments 908 and 909, respectively. STA111 and STA112 send Block Ack frames in the second and first frequency domains, respectively. After sending acknowledgment 908, STA111 may move to the first frequency domain. This allows STA111 to respond to subsequent communications taking place in the first frequency domain, including the PCH.

[0072] (Processing performed when the AP performs downlink communication) An example of the processing flow executed by AP101 when performing downlink communication will be explained using Figure 10. Figure 10 is, for example, the processing flow executed by AP101 when performing downlink communication in Figure 9. This processing flow may be initiated when data destined for STA110 is accumulated in AP101's transmit buffer. In this example, AP101 is assumed to have accumulated multiple data destined for STA111 and STA112, respectively. First, AP101 allocates frequency resources to each STA110 based on the fact that multiple data destined for STA111 and STA112 have been accumulated in its device (S1001). For example, AP101 may allocate frequency resources based on whether each STA110 is in a state where it can execute DSO. Note that a state where it can execute DSO may be a state in which STA110 has the function to execute DSO and has enabled the function to execute DSO. A state in which DSO cannot be executed may be a state in which STA110 does not have the function to execute DSO or has the function to execute DSO disabled. For example, AP101 may allocate a frequency resource in a first frequency domain including the PCH to STA112 based on the fact that STA112 is in a state in which DSO cannot be executed. Also, AP101 may allocate a frequency resource in a first frequency domain including the PCH or a frequency resource in a second frequency domain not including the PCH to STA111 based on the fact that STA111 is in a state in which DSO can be executed. In this example, let's assume that AP101 allocates a frequency resource in the first frequency domain to STA112, which is in a state in which DSO cannot be executed, and allocates a frequency resource in the second frequency domain to STA111, which is in a state in which DSO can be executed. Note that if there are three or more frequency domains set between AP101 and STA111, AP101 may select one of the frequency domains to allocate the frequency resource. For example, if the frequency switching delay of STA111 differs depending on the distance it moves along the frequency axis, AP101 may prioritize selecting a frequency range where the frequency switching delay of STA111 is small (e.g., where the travel distance is small).By reducing the frequency switching delay, the AP is more likely to complete its movement along the frequency axis and perform DSO within an acceptable time, allowing for a reduction in the amount of padding added to the frame by AP101. Furthermore, if AP101 can obtain interference information from STA111 in each frequency domain, it may prioritize selecting frequency domains with less interference. Also, if AP101 has two or more STA110s capable of performing DSO connected to its device, it can allocate frequency resources in frequency domains other than the first frequency domain including the PCH to multiple STA110s. In this case, AP101 can allocate frequency resources such that STA110s that can use frequency domains further from the PCH are allocated frequency resources in more distant frequency domains. This can increase the number of STA110s that can communicate in parallel, allowing AP101 to use its available frequency band more efficiently.

[0073] If AP101 allocates a frequency resource in the first frequency domain, including the PCH, to either STA111 or STA112 (NO in S1002), it uses the allocated frequency resource to transmit to each STA110 (S1003). For example, AP101 can transmit data to each STA110 in parallel by using a UHR MU PPDU that supports OFDMA communication. In this case, AP101 can transmit a PPDU containing data without transmitting MU-RTS frames or receiving CTS frames. AP101 can also notify each STA of the frequency resource allocated to it using the UHR SIG field in the preamble of the UHR MU PPDU.

[0074] On the other hand, if AP101 allocates a frequency resource in the second frequency domain to at least one of STA111 and STA112 (YES in S1002), it instructs them to move to the second frequency domain (S1004). For example, in this example, AP101 may instruct STA111 to move to the second frequency domain using a MU-RTS frame. In this case, as will be described later, AP101 may use the PS160 subfield and the RU Allocation subfield of the User Info field included in the MU-RTS to notify each of the STA110s of the frequency resources allocated to them. STA110 may determine that it should move to the second frequency domain based on the fact that the allocated RU is included in the second frequency domain. AP101 may also use some of these subfields to notify STA110 of information that identifies the frequency domain containing the frequency resources allocated to it, and may notify information that identifies the frequency resources in a subsequent PPDU containing data. For example, AP101 may use the PS160 subfield and the B0 bit of the RU Allocation subfield to notify STA110 of the frequency domain containing the frequency resources allocated to it. AP101 may also use other frames to instruct STA110 to move to another frequency domain. For example, if a new type of frame is defined to indicate that STA110 should move to another frequency domain, AP101 may use this frame to give instructions. In this case, after sending a frame instructing STA110 to move to another frequency domain, STA110 may request that each STA110 send a CTS frame by sending MU-RTS frames or RTS frames in their respective frequency domains. In this case, AP101 can confirm that the STA110 has completed its frequency domain move by receiving the CTS frames corresponding to the MU-RTS frames or RTS frames in their respective frequency domains.

[0075] Furthermore, when AP101 notifies STA110 that it should switch to a second frequency domain, it may adjust the frame size to take into account the time required for STA111 to switch the frequency band it will be using. In a normal exchange of MU-RTS frames and CTS frames, communication device 100 receives the MU-RTS frame and transmits the CTS frame after SIFS. However, when STA110 moves along the frequency axis, it may not be able to transmit the CTS frame in the destination frequency domain after receiving the MU-RTS frame and SIFS. In response to this, AP101 may adjust the frame size to take into account the frequency switching delay of STA110 when notifying STA110 that it should switch to a second frequency domain. For example, AP101 may add a predetermined padding to the MU-RTS frame. As an example, AP101 may add padding such that the time from the completion of transmission of the User Info field corresponding to STA110 to the completion of transmission of the MU-RTS frame is longer than the frequency switching delay of STA110. This allows STA110 to complete transmission of the MU-RTS frame and transmit the CTS frame after SIFS, even if it starts changing frequencies only after it has finished receiving the User Info field corresponding to its own device. AP101 may also place the User Info corresponding to STA110 with a large frequency switching delay near the beginning of the MU-RTS frame. This allows STA110 to change frequencies while User Info fields for STA110s other than its own device are being transmitted.

[0076] If AP101 notifies STA110 that it should move to the second frequency domain, it waits for a response for a predetermined period (S1005). For example, after transmitting a MU-RTS frame, AP101 waits for a predetermined period to receive a CTS frame. This predetermined period may be SIFS or longer. If AP101 receives CTS frames from all STA110s that were the destination of the MU-RTS frame (YES in S1005), AP101 transmits data to each STA110 using the frequency resources allocated in S1001 (S1006). On the other hand, if AP101 does not receive a CTS frame from one or more of the STA110s that were the destination of the MU-RTS frame (NO in S1005), it transmits data to the STA110 that sent the received CTS frame (S1007). In this case, AP101 does not transmit data to STA110s that were not confirmed to have transmitted a CTS frame for the MU-RTS frame.

[0077] AP101 transmits data in parallel to multiple STA110s using an OFDMA-compatible UHR MU PPDU. In this case, AP101 may notify the RU assigned to each STA110 in the preamble of the UHR MU PPDU. AP101 terminates the transmission process when it receives an acknowledgment from the STA110 that sent the data. AP101 may also refrain from the next communication for a period of time equivalent to the frequency switching delay required for an STA111 that has moved to the second frequency domain to move back to the first frequency domain.

[0078] (Processing performed when STA performs downlink communication) Next, an example of the processing flow executed by STA110 when performing downlink communication will be explained using Figure 11. Figure 11 is, for example, the processing flow executed by STA111 in Figure 9 when performing downlink communication. First, STA110 receives a frame in the PCH of the first frequency domain (S1101). STA110 determines whether the received frame contains an instruction for its own device to move to the second frequency domain (S1102). For example, if the received frame is a MU-RTS frame, STA110 may identify the frequency resource assigned to its own device in the User Info field corresponding to its own device. If the identified frequency resource is a frequency resource included in the second frequency domain, STA110 may determine that it should move to the second frequency domain. Furthermore, if the received frame contains information indicating that a frequency resource included in the second frequency domain has been assigned to its own device, STA110 may determine that it should move to the second frequency domain based on this information. Furthermore, if the received frame contains an instruction that the device should move to a second frequency domain, the STA110 may determine that it should move to the second frequency domain based on this instruction.

[0079] If STA110 determines, based on the received frame, that it should move to the second frequency domain (YES in S1102), it moves to the second frequency domain (S1103). For example, if STA110 determines that it should move to the second frequency domain based on information obtained from the User Info field corresponding to its own device in the MU-RTS frame, it may start moving as soon as it has finished receiving the User Info field. In this case, if STA110 completes the move to the second frequency domain before the timer started at the start of the move expires (S1104), it sends a CTS frame in the second frequency domain as a response to the MU-RTS frame (S1105). STA110 waits for data from AP101 in the second frequency domain. On the other hand, if STA110 does not complete the move to the second frequency domain before the timer expires (NO in S1104), it returns to the first frequency domain without responding to the MU-RTS frame and completes processing.

[0080] On the other hand, if STA110 does not determine that it should move to the second frequency domain (NO in S1102), it continues to communicate in the first frequency domain. For example, if the received frame is a MU-RTS frame, STA110 sends a response after SIFS from the completion of reception (S1105) and waits for data from AP101.

[0081] STA110 receives data from AP101 (S1106). For example, STA110 receives an OFDMA-compatible UHR MU PPDU and retrieves data addressed to itself contained in the received PPDU. In this case, the RU assigned for the data addressed to STA110 may be indicated in the PPDU's preamble. STA110 sends an acknowledgment in the frequency domain containing the RU that received the data. If STA110 moves to a second frequency domain, it sends an acknowledgment and then moves back to the first frequency domain.

[0082] (Uplink data communication processing between AP and STA) Figure 12 shows an example sequence of uplink communication where STA110 transmits data to AP101. OFDMA is assumed to be used in this communication. For example, each STA110 transmits data using a UHR TB PPDU corresponding to OFDMA. UHR TB PPDU is an abbreviation for Ultra High Reliability Trigger-based PPDU. In this example, AP101 and STA111 are capable of performing DSO-based communication, while STA112 is not. Also, as in Figure 9, the connection between AP101 and STA111 is assumed to have two 160MHz bandwidth frequency domains configured for DSO execution within the frequency band used by AP101. STA111 and STA112 are accumulating data, and AP101 is assumed to be aware that each STA110 is accumulating data. AP101 shall allocate a first frequency domain frequency resource to STA112, which cannot use DSO, and a second frequency domain frequency resource to STA111, which can perform DSO, in order to transmit this data.

[0083] First, AP101 sends notification 1201 to move STA111 to the second frequency domain prior to data transmission by STA110. For example, AP101 may send a Trigger frame as notification 1201. This Trigger frame may be a Basic type Trigger frame. AP101 sends the Trigger frame in the first frequency domain, including the PCH, so that both STA111 and STA112 can receive it. The Trigger frame may include User Info fields corresponding to STA111 and STA112, respectively. The User Info fields may contain information indicating the frequency resources assigned to the corresponding STA110. For example, AP101 may implicitly instruct STA111 to move to the second frequency domain by notifying it of the allocation of frequency resources in the second frequency domain using the User Info field corresponding to STA111. AP101 may also notify each STA110 of the frequency resources (RU) assigned to them using the User Info field corresponding to each STA110. This allows AP101 to instruct STA111 to move to the second frequency domain and to notify each STA110 of the frequency resources assigned to them, all in a single notification. AP101 may notify STA111 of the instruction to move to the second frequency domain and to notify each STA110 of the frequency resources assigned to them using different information or different frames. For example, a new field for instructing the movement to the frequency domain may be defined in the Trigger frame, or a new frame for instructing the movement to the frequency domain may be defined. This allows AP101 to explicitly notify STA111 that it should move to the second frequency domain. AP101 may also add padding 1202 to the frame used for notification 1201. Padding 1202 may be added based on the frequency switching delay for STA111 to move to the second frequency domain.

[0084] When STA111 receives notification 1201, it moves to the second frequency domain. For example, if notification 1201 is a Basic type Trigger frame, STA111 can determine from the information contained in the User Info field associated with its own device that frequency resources in the second frequency domain have been allocated to its own device. In this case, STA111 can determine that it should move to the second frequency domain based on the fact that frequency resources in the second frequency domain have been allocated to its own device. After moving to the second frequency domain, STA111 transmits data 1204 using the frequency resources allocated to its own device. STA111 may also transmit data 1204 if the time taken from the start of the move to the second frequency domain until it is ready to transmit data is less than or equal to the allowable time notified by AP101. In this case, STA111 starts moving to the second frequency domain and activates timer 1203 once it has finished receiving the User Info field associated with its own device. Timer 1203 may be set to expire within the allowable time notified by AP101. When STA111 transmits data 1204, it transmits data 1204 if timer 1203 has not expired, and does not transmit data 1204 if timer 1203 has expired. This prevents STA111 from transmitting data 1204 at a time exceeding the acceptable time for AP101.

[0085] When STA112 receives notification 1201, it transmits data 1205 in the first frequency domain. For example, if notification 1201 is a Basic type Trigger frame, STA112 transmits data 1205 using the frequency resources allocated in the User Info field corresponding to its own device in the Trigger frame.

[0086] AP101 sends an acknowledgment when it receives data from each of the STA110s. For example, AP101 can send an acknowledgment by transmitting a Block Ack frame. AP101 sends a Block Ack frame 1206 in the second frequency domain in response to data 1204 received from STA111 in the second frequency domain. AP101 also sends a Block Ack frame 1207 in the first frequency domain in response to data 1205 received from STA112 in the first frequency domain. STA110 completes its transmission process upon receiving an acknowledgment for the data it transmitted. After STA111 has received the Block Ack 1206 for data 1204, it moves to the first frequency domain.

[0087] (Processing performed when the AP makes an uplink connection) An example of the processing flow executed by AP101 when performing uplink communication is explained using Figure 13. Figure 13 is, for example, the processing flow executed by AP101 when performing uplink communication as shown in Figure 12. This processing flow may be initiated when AP101 detects that data is being stored in STA110. AP101 may obtain information from each STA110 to determine whether or not data is stored in each STA110. For example, AP101 may inquire about the presence or absence of data stored in STA110 by sending a Buffer Status Report Polling (BSRP) frame to STA110. Upon receiving the BSRP frame, STA110 may notify AP101 of the Buffer Status Report. In this way, AP101 can obtain the data storage status of each STA110.

[0088] AP101 allocates frequency resources to each of the one or more STA110s that are storing data (S1301). For example, AP101 may allocate frequency resources based on whether each STA110 is in a state where it can perform DSO, similar to S1001 in Figure 10. In this example, AP101 allocates frequency resources in the first frequency domain to STA112, which is in a state where it cannot perform DSO, and allocates frequency resources in the second frequency domain to STA111, which is in a state where it can perform DSO.

[0089] If AP101 allocates a frequency resource in the first frequency domain, including the PCH, to either STA111 or STA112 (NO in S1302), it issues a notification indicating that no frequency resources in the second frequency domain have been allocated (S1303). For example, AP101 may issue this notification by sending a Basic type Trigger frame containing information indicating the first frequency domain frequency resources allocated to each of the STA110s. On the other hand, if AP101 allocates a frequency resource in the second frequency domain to one or more of the STA110s (YES in S1302), it issues a notification indicating that a frequency resource in the second frequency domain has been allocated (S1304). By issuing a notification indicating that a frequency resource in the second frequency domain has been allocated, AP101 can implicitly instruct the STA110s to move to the second frequency domain. Alternatively, AP101 may also issue a notification to the STA110s explicitly instructing them to move to the second frequency domain. For example, AP101 may send a Basic type Trigger frame containing information indicating the frequency resources in the second frequency domain allocated to STA110. In this case, AP101 may notify STA110 of the allocated RUs using the PS160 subfield and the RU Allocation subfield of the User Info field corresponding to each STA110 included in the Trigger frame. Based on the fact that the allocated RUs are in the second frequency domain, STA110 may determine that it should move to the second frequency domain. AP101 may also adjust the frame size in the notification indicating that there is an allocation of frequency resources in the second frequency domain, similar to S1004 in Figure 10.

[0090] AP101 receives data from each of the STA110s (S1305). For example, AP101 may receive UHR TB PPDUs from each STA110 that are transmitted using the frequency resources allocated to each STA110. AP101 acknowledges the received data and terminates the reception process. For example, if AP101 does not allocate frequency resources in the second frequency domain, it may acknowledge by sending a Multi-STA Block ACK in the first frequency domain. A Multi-STA Block ACK is a frame used to acknowledge multiple STAs using a single frame. Alternatively, if AP101 allocates frequency resources in the second frequency domain to STA111 and frequency resources in the first frequency domain to STA112, it may send Block ACKs in each frequency domain. For example, AP101 may send a Block ACK acknowledgment in the first frequency domain for data received from STA112, and a Block ACK acknowledgment in the second frequency domain for data received from STA111. Furthermore, when AP101 allocates frequency resources in the second frequency domain to STA111, it may add padding to the Block ACK frame, similar to the notification in S1304 indicating the allocation of frequency resources in the second frequency domain. In this case, AP101 may add padding to the Block ACKs it transmits in each frequency domain. This prevents the next communication from being executed until STA111 becomes ready to communicate in the first frequency domain.

[0091] (Processing performed when STA performs uplink communication) Next, we will explain an example of the processing flow that STA110 performs when performing uplink communication, using Figure 14. Figure 14 is, for example, the processing flow that STA111 performs when performing uplink communication in Figure 12. First, STA110 receives a frame in the PCH of the first frequency domain (S1401). STA110 determines whether the received frame contains an instruction indicating that its own device should move to the second frequency domain (S1402). For example, if the received frame is a Basic type Trigger frame, STA110 may identify the frequency resource assigned to its own device in the User Info field corresponding to its own device. If the identified frequency resource is a frequency resource included in the second frequency domain, STA110 may determine that it should move to the second frequency domain.

[0092] If STA110 determines, based on the received frame, that it should move to the second frequency domain (YES in S1402), it moves to the second frequency domain (S1403). For example, if STA110 determines that it should move to the second frequency domain based on information obtained from the User Info field corresponding to its own device in the Trigger frame, it may start moving as soon as it has finished receiving the User Info field. In this case, if STA110 completes the move to the second frequency domain before the timer started at the start of the move expires (S1404), it transmits data using the frequency resources allocated to its own device in the second frequency domain (S1405). For example, STA110 transmits a UHR TB PPDU using the RU allocated to its own device by the Trigger frame. On the other hand, if STA110 does not complete the move to the second frequency domain before the timer expires (NO in S1404), it returns to the first frequency domain without transmitting data and completes the process.

[0093] On the other hand, if STA110 does not determine that it should move to the second frequency domain (NO in S1402), it continues to communicate in the first frequency domain. For example, if the received frame is a trigger frame, STA110 transmits data using the frequency resources allocated to itself (S1405).

[0094] (Configuration of information used for data communication between AP and STA) This section describes the structure of the information used by AP101 to notify STA110 of the frequency resources it has allocated. Figure 15 shows an example of the structure of the User Info field included in the Trigger frame used by AP101 to notify STA110 of the frequency resources it has allocated. The Trigger frame may contain one or more User Info fields corresponding to one or more destination STA110s. The User Info field shown in Figure 15 may be included in a Basic type Trigger frame or MU-RTS frame. The User Info field shown in Figure 15 may also be included in a new frame defined by AP101 to cause STA110 to move in the frequency domain. The User Info field in Figure 15 may consist of an AID 12 subfield 1501, a RU Allocation subfield 1502, and a PS160 subfield 1503. The AID 12 subfield 1501 contains information to identify the STA110 corresponding to this User Info field. For example, the AID 12 subfield indicates the 12th digit of the AID assigned to STA110 when AP101 established a connection with STA110. AID is an abbreviation for Association ID. STA110 can determine whether a User Info field corresponds to its own device based on whether the value of the AID 12 subfield contained in each User Info field matches the 12th digit of its own device's AID. The RU Allocation field 1502 and PS160 field 1503 are specific information for uniquely identifying the frequency resource allocated to STA110 corresponding to this User Info field.

[0095] An example of the mapping between the values ​​in the RU Allocation field 1502 and the PS160 field 1503 and frequency resources (RUs) is explained using Figure 16. In Figure 16, PS160 represents the value in the PS160 field 1503. B0 represents the value of the 0th bit of the RU Allocation field 1502. B7-B1 represent the decimal values ​​indicated by the 7th to 1st bits of the RU Allocation field 1502, and each value corresponds to a RU indicated by the RU index. For example, if the values ​​of B7-B1 are 0, it indicates that a 26-tone RU with an RU index of RU1 will be allocated. RU or MRU size indicates the size of the allocated RU, from 26-tone RUs to 996-tone RUs. Bandwidth corresponds to the total frequency bandwidth used by AP101. The RU index indicates the range of RU indices that AP101 can allocate to STA110. For example, RUs with RU index 1-9 can be assigned to STA110 when the bandwidth used by AP101 is 20MHz to 320MHz. On the other hand, RUs with RU index 10-37 cannot be assigned to STA110 when the bandwidth used by AP101 is 20MHz. This is because, as shown in Figure 17, RU index 10-37 is a value assigned when the frequency bandwidth exceeds 20MHz. Now, let's assume that the usable frequency bandwidth of STA110 is 20MHz, DSO cannot be used, and the PCH is 20MHz, corresponding to RU index 1-9 shown in Figure 17. In this case, 26-tone RUs in the range of RU index 1-9 can be assigned to this STA110. Similarly, 52-tone RUs in the range of RU index 1-4, 106-tone RUs in the range of RU index 1-2, and 242-tone RUs in RU index 1 can be assigned to this STA110. On the other hand, the STA110, which is capable of DSO, can expand its usable frequency bandwidth by moving along the frequency axis within the frequency band used by the AP101.The travel distance that STA110 can move on the frequency axis is indicated by the DSO Subbandwidth field 808 mentioned above. This increases the number of RUs that can be allocated to STA110. For example, if the bandwidth used by STA110 is 20 MHz and the travel distance is 20 MHz, STA110 can use a bandwidth equivalent to 40 MHz through the DSO. Therefore, STA110 can be allocated 26-tone RUs in the range of RU index 1-18. Similarly, such STA110 can be allocated 52-tone RUs in the range of RU index 1-8, 106-tone RUs in the range of RU index 1-4, and 242-tone RUs in the range of RU index 1-2. Also, for example, if the travel distance of STA110 is 60 MHz, STA110 that can use a bandwidth equivalent to 80 MHz through the DSO can be allocated 26-tone RUs in the range of RU index 1-37. Similarly, 52-tone RUs in the RU index 1-16 range, 106-tone RUs in the RU index 1-4 range, and 242-tone RUs in the RU index 1-4 range can be assigned to this STA110.

[0096] If the frequency bandwidth used by AP101 in OFDMA exceeds 80MHz, the allocation of RUs is notified by a combination of the 80MHz bandwidth subblocks indicated by PS160 and B0 and the RU index. For example, if AP101 uses a PPDU with a frequency bandwidth of 320MHz for OFDMA communication, four 80MHz bandwidth subblocks are set. In Figure 16, each of the 2 bits indicated by PS160 and B0, from 0 to 3, corresponds to the first to fourth subblocks. STA110 can identify the subblock containing the frequency resources allocated to its device from the values ​​indicated by PS160 and B0, and identify the RUs allocated to its device from the values ​​indicated by B7-B1.

[0097] AP101 can use the frequency resource allocation information configured as described above to notify STA110 that it should move to a different frequency domain. For example, if the bandwidths of the frequency domains set between AP101 and STA110 are 160 MHz, AP101 can use the value of PS160 to notify STA110 that it should move to a different frequency domain. For example, by setting the value of PS160 to 1, AP101 can notify STA110 that it should move to a second frequency domain. For example, if the bandwidths of the frequency domains set between AP101 and STA110 are 80 MHz, AP101 can use the value of PS160 and the value of B0 to notify STA110 that it should move to a different frequency domain. For example, by using the value of PS160 and the value of B0 to notify STA110 of a value between 1 and 3, AP101 can notify STA110 that it should move to a second to fourth frequency domain. Furthermore, if the respective bandwidths of the frequency domains set with STA110 are 20MHz or 40MHz, AP101 can use the values ​​of PS160, B0, and B7-B1 to notify STA110 that it should move to a different frequency domain. For example, AP101 can use the values ​​of PS160 and B0 to notify STA110 of values ​​1 to 3, thereby notifying STA110 that frequency resources have been allocated to the second subblock to subblock 4. AP101 can then use the values ​​of B7-B1 to notify STA110 of the allocated RU, thereby notifying STA110 of the frequency domain to which it should move. For example, suppose AP101 sends a frame containing an RU Allocation subfield with B7-B1 values ​​set to 9 to STA110, which has an available bandwidth of 20MHz and can use a bandwidth equivalent to 40MHz. In this case, STA110 can determine that frequency resources in a second frequency domain with a bandwidth of 20MHz have been allocated to its device. This allows STA110 to determine that it should move to the second frequency domain. Furthermore, if the bandwidths of the frequency domains set with STA110 are 20MHz or 40MHz, AP101 can notify the destination frequency domain using the PS160 value, the B0 value, and a newly established field.For example, if the bandwidths of the frequency domains set between AP101 and STA110 are 40MHz, AP101 notifies STA110 of the subblock to which it should move based on the values ​​of PS160 and B0. AP101 can then use a newly added 1 bit to notify whether it should move to the lower 40MHz frequency domain or the upper 40MHz frequency domain within the 80MHz bandwidth subblock. Similarly, if the bandwidths of the frequency domains set between AP101 and STA110 are 20MHz, AP101 notifies STA110 of the subblock to which it should move based on the values ​​of PS160 and B0. AP101 can then use two newly added bits to notify which of the first to fourth 20MHz frequency domains within the 80MHz bandwidth subblock it should move to.

[0098] Furthermore, when AP101 notifies STA110 to move frequency domains using a MU-RTS frame during downlink communication, it can use this MU-RTS frame to notify multiple types of information at once. For example, AP101 can use a MU-RTS frame to notify STA110 whether or not to move frequency domains, the frequency resources allocated to STA110, and the channel on which STA110 should transmit CTS frames, all at once. As an example, AP101 can use the PS160 value, the B0 value, and the B7-B1 values ​​of the MU-RTS frame to notify STA110 of the frequency resources allocated to it. In this case, AP101 can use a value of 60 or less for B7-B1 to notify the allocation of an RU with a bandwidth smaller than 20 MHz, as shown in Figure 16. AP101 can also implicitly notify STA110 that it should move frequency domains by indicating that the frequency domain containing the frequency resources allocated to STA110 does not include a PCH. Furthermore, AP101 can notify STA110 of the RU it has assigned, thereby informing STA110 that it should transmit CTS frames on the 20MHz channel containing that RU. Based on the received MU-RTS frames, STA110 can identify the frequency domain to which it should move, the channel on which it should transmit CTS frames, and the RU on which it should receive data.

[0099] Figure 16 illustrates the frequency resource allocation when AP101 assigns one RU to STA110. Even when AP101 assigns multiple RUs to STA110, similar operation is possible based on the MRU allocation specified in the IEEE 802.11be standard. MRU stands for Multiple Resource Unit. For example, if STA110 has a usable bandwidth of 20 MHz and can use a bandwidth equivalent to 80 MHz by running DSO, setting B7-B1 to a value of 75 may indicate an RU allocation of 52 tones + 26 tones with MRU index 6. In this case, AP101 can implicitly notify STA110 to move to a second frequency domain with a bandwidth of 20 MHz.

[0100] As described above, according to this embodiment, AP101 acquires capability information indicating whether or not STA110 has the capability to perform communication using DSO, and selects a frequency domain that includes the frequency resources to be allocated based on the capability information of STA110. STA110 moves to the frequency domain that includes the frequency resources allocated to itself and performs communication with AP101. With this configuration, AP101 can perform OFDMA communication using a wider bandwidth than the corresponding bandwidths of each STA110 connected to itself, even if those bandwidths are narrow. This allows AP101 to utilize unused frequency bands within its available frequency band, thereby improving frequency utilization efficiency. In this embodiment, the DSO Padding delay field 806 to the DSO subbandwidth field 808 were described using an example where they are included in a Probe Request frame, etc. Similarly, the DSO Padding Timeout field 809 and the DSO Transition Timeout field 810 were described using an example where they are included in a Probe Response frame, etc. These fields may also be included in other frames. For example, the communication device 100 may include these fields in a Public Action frame or a Protected Public Action frame. Public Action frames and Protected Public Action frames can be used to indicate whether the DSO function has been enabled or disabled. That is, the communication device 100 can notify communication parameters for executing the DSO function along with information indicating that the state of the DSO function in its own device has changed. In this case, AP 101 can switch whether to enable or disable the DSO function for each STA 110 based on the notification from STA 110.

[0101] In this embodiment, the operation of communicating using a frequency domain that does not include the PCH is exemplified as DSO, but it is not limited to this and may be referred to by other names. In this embodiment, the frequency domain that includes the PCH is exemplified as the first frequency domain, the frequency domain that does not include the PCH is exemplified as the second frequency domain, etc., but it is not limited to this and may be referred to by other names. Also, the parameters referred to as frequency switching delay, frequency switching position, etc. in this embodiment may be referred to by other names. Similarly, the fields and subfields included in the configuration examples in Figures 8 and 15 may be referred to by other names. The setting values ​​and corresponding values ​​of the information shown in Figure 16 and Tables 1 to 4 may be configured to be different.

[0102] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0103] (Summary of the embodiments) At least some of the embodiments described above can be summarized as follows: (Item 1) A communication device capable of communicating with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, In the first frequency band of the first bandwidth used by the communication device for communication, there exists a second frequency band determined based on a second bandwidth that the other communication device can handle, and a third frequency band other than the second frequency band. The aforementioned communication device is In frequency division multiplexing communication performed by the communication device with a plurality of devices including the other communication device, when the frequency resources of the second frequency band are allocated to a device other than the other communication device, acquisition means for acquiring capability information from the other communication device indicating whether or not the other communication device has the capability to change the frequency band used from the second frequency band to a fourth frequency band of the second bandwidth including a part of the third frequency band, and perform the frequency division multiplexing communication; It includes communication means for allocating frequency resources to the aforementioned other communication device and communicating with said other communication device, The aforementioned communication means is Based on the fact that the other communication device does not have the predetermined capability, a frequency resource from the second frequency band is allocated to the other communication device without changing the frequency band used by the other communication device. Based on the fact that the other communication device has the predetermined capabilities, frequency resources are allocated to the other communication device from the second frequency band, or from the fourth frequency band by changing the frequency band used by the other communication device to the fourth frequency band. A communication device characterized by the following features. (Item 2) The communication means communicates with the other communication device using Orthogonal Frequency Division Multiple Access (OFDMA). A communication device as described in item 1, characterized by the features described herein. (Item 3) When the communication means allocates frequency resources from the fourth frequency band to the other communication device, An instruction is given in the second frequency band to change the frequency band used by the other communication device from the second frequency band to the fourth frequency band. The response to the instruction from the other communication device is received in the fourth frequency band. Data communication with the aforementioned other communication device is performed in the fourth frequency band. A communication device according to item 1 or 2, characterized by the features described above. (Item 4) The capability information includes information for identifying a range on the frequency axis that the other communication device can set as the fourth frequency band. A communication device characterized by any one of items 1 to 3. (Item 5) The capability information includes information for identifying the time required for the other communication device to transition from a state in which it is communicating in the second frequency band to a state in which it is capable of communicating in the fourth frequency band. A communication device characterized by any one of items 1 to 4. (Item 6) The acquisition means acquires the capability information using a frame that includes a UHR Capabilities element. A communication device characterized by any one of items 1 to 5. (Item 7) The communication means notifies the other communication device of the frequency resource it has allocated, by providing information for identifying the frequency band containing the frequency resource and information for uniquely identifying the frequency resource within that frequency band. A communication device characterized by any one of items 1 to 6. (Item 8) A communication device capable of communicating with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, In the first frequency band of the first bandwidth used for communication by the other communication device, there exists a second frequency band determined based on a second bandwidth that the communication device can handle, and a third frequency band other than the second frequency band. The aforementioned communication device is In frequency division multiplexing communication performed by the other communication device between the communication device and a plurality of other devices, when the frequency resources of the second frequency band are allocated to a device other than the communication device, a notification means notifies the other communication device of capability information indicating whether the communication device has the capability to change the frequency band used from the second frequency band to a fourth frequency band of the second bandwidth including a part of the third frequency band, and to perform the frequency division multiplexing communication; From the aforementioned other communication device, The frequency resources within the second frequency band allocated based on the fact that the communication device does not have the predetermined capability, Acquisition means for acquiring specific information that identifies a frequency resource in the second frequency band or a frequency resource in the fourth frequency band, which is allocated based on the fact that the communication device has the predetermined capability, When a frequency resource in the fourth frequency band is allocated, a changing means for changing the frequency band to be used to the fourth frequency band, The system includes communication means for communicating with other communication devices using specified frequency resources. A communication device characterized by the following features. (Item 9) The communication means communicates with the other communication device using Orthogonal Frequency Division Multiple Access (OFDMA). A communication device as described in item 8, characterized by the features described above. (Item 10) When an instruction is received to change the frequency band used by the communication device from the second frequency band to the fourth frequency band, The modification means changes the frequency band used by the communication device from the second frequency band to the fourth frequency band. The aforementioned communication means is The response to the instruction from the other communication device is transmitted in the fourth frequency band. Data communication with the aforementioned other communication device is performed in the fourth frequency band. A communication device according to item 8 or 9, characterized by the features described above. (Item 11) The notification means notifies the capability information, which includes information for identifying the range on the frequency axis that the communication device can set as the fourth frequency band. A communication device as described in any one of items 8 to 10, characterized by the features described therein. (Item 12) The notification means notifies the capability information, which includes information for specifying the time required for the communication device to move from a state in which it is communicating in the second frequency band to a state in which it is capable of communicating in the fourth frequency band. A communication device as described in any one of items 8 to 11, characterized by the features described therein. (Item 13) The notification means notifies the capability information using a frame that includes a UHR Capabilities element. A communication device according to any one of items 8 to 12, characterized by the features described above. (Item 14) The specified information includes information for identifying a frequency band containing the frequency resources allocated to the communication device, and information for uniquely identifying the frequency resources allocated to the communication device within that frequency band. A communication device as described in any one of items 8 to 13, characterized by the features described herein. (Item 15) A control method performed by a communication device capable of communicating with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, In the first frequency band of the first bandwidth used by the communication device for communication, there exists a second frequency band determined based on a second bandwidth that the other communication device can handle, and a third frequency band other than the second frequency band. The control method described above is In frequency division multiplexing communication performed by the communication device with a plurality of devices including the other communication device, when the frequency resources of the second frequency band are allocated to a device other than the other communication device, the acquisition step of capability information obtained from the other communication device indicating whether or not the other communication device has the capability to change the frequency band used from the second frequency band to a fourth frequency band of the second bandwidth including a part of the third frequency band, and perform the frequency division multiplexing communication; The process includes allocating frequency resources to the aforementioned other communication device and performing communication with said other communication device, The aforementioned communication process is, Based on the fact that the other communication device does not have the predetermined capability, a frequency resource from the second frequency band is allocated to the other communication device without changing the frequency band used by the other communication device. Based on the fact that the other communication device has the predetermined capabilities, frequency resources are allocated to the other communication device from the second frequency band, or from the fourth frequency band by changing the frequency band used by the other communication device to the fourth frequency band. A communication method characterized by the following features. (Item 16) A control method performed by a communication device capable of communicating with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, In the first frequency band of the first bandwidth used for communication by the other communication device, there exists a second frequency band determined based on a second bandwidth that the communication device can handle, and a third frequency band other than the second frequency band. The control method described above is In frequency division multiplexing communication performed by the other communication device between the communication device and a plurality of other devices, if the frequency resources of the second frequency band are allocated to a device other than the communication device, the communication device notifies the other communication device of capability information indicating whether or not it has the capability to change the frequency band used from the second frequency band to a fourth frequency band of the second bandwidth including a part of the third frequency band, and perform the frequency division multiplexing communication; From the aforementioned other communication device, The frequency resources within the second frequency band allocated based on the fact that the communication device does not have the predetermined capability, An acquisition step of acquiring specific information that identifies a frequency resource in the second frequency band or a frequency resource in the fourth frequency band, which is allocated based on the fact that the communication device has the predetermined capability; When a frequency resource in the fourth frequency band is allocated, the process includes a change step of changing the frequency band to be used to the fourth frequency band, The system includes a communication step of communicating with the other communication device using specified frequency resources. A control method characterized by the following: (Item 17) A program to cause a computer to function as one of the means of a communication device described in any one of items 1 through 14.

[0104] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0105] 101: AP, 111: STA, 112: STA, 121: Network

Claims

1. A communication device capable of communicating with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, In the first frequency band of the first bandwidth used by the communication device for communication, there exists a second frequency band determined based on a second bandwidth that the other communication device can handle, and a third frequency band other than the second frequency band. The aforementioned communication device is In frequency division multiplexing communication performed by the communication device with a plurality of devices including the other communication device, when the frequency resources of the second frequency band are allocated to a device other than the other communication device, the acquisition means acquires capability information from the other communication device indicating whether or not the other communication device has the capability to change the frequency band used from the second frequency band to a fourth frequency band of the second bandwidth including a part of the third frequency band, and perform the frequency division multiplexing communication. It includes communication means for allocating frequency resources to the aforementioned other communication device and communicating with said other communication device, The aforementioned communication means is Based on the fact that the other communication device does not have the predetermined capability, a frequency resource from the second frequency band is allocated to the other communication device without changing the frequency band used by the other communication device. Based on the fact that the other communication device has the predetermined capabilities, frequency resources are allocated to the other communication device from the second frequency band, or from the fourth frequency band by changing the frequency band used by the other communication device to the fourth frequency band. A communication device characterized by the following features.

2. The communication means communicates with the other communication device using Orthogonal Frequency Division Multiple Access (OFDMA). The communication device according to feature 1.

3. When the communication means allocates frequency resources from the fourth frequency band to the other communication device, An instruction is given in the second frequency band to change the frequency band used by the other communication device from the second frequency band to the fourth frequency band. The response to the instruction from the other communication device is received in the fourth frequency band. Data communication with the aforementioned other communication device is performed in the fourth frequency band. The communication device according to feature 1.

4. The capability information includes information for identifying a range on the frequency axis that the other communication device can set as the fourth frequency band. The communication device according to feature 1.

5. The capability information includes information for identifying the time required for the other communication device to transition from a state in which it is communicating in the second frequency band to a state in which it is capable of communicating in the fourth frequency band. The communication device according to feature 1.

6. The acquisition means acquires the capability information using a frame that includes a UHR Capabilities element. The communication device according to feature 1.

7. The communication means notifies the other communication device of the frequency resource allocated to it by providing information for identifying the frequency band containing the frequency resource and information for uniquely identifying the frequency resource within that frequency band. The communication device according to feature 1.

8. A communication device capable of communicating with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, In the first frequency band of the first bandwidth used for communication by the other communication device, there exists a second frequency band determined based on a second bandwidth that the communication device can handle, and a third frequency band other than the second frequency band. The aforementioned communication device is In frequency division multiplexing communication performed by the other communication device between the communication device and a plurality of other devices, when the frequency resources of the second frequency band are allocated to a device other than the communication device, a notification means notifies the other communication device of capability information indicating whether the communication device has the capability to change the frequency band used from the second frequency band to a fourth frequency band of the second bandwidth including a part of the third frequency band, and to perform the frequency division multiplexing communication; From the aforementioned other communication device, The frequency resources within the second frequency band allocated based on the fact that the communication device does not have the predetermined capability, Acquisition means for acquiring specific information that identifies a frequency resource in the second frequency band or a frequency resource in the fourth frequency band, which is allocated based on the fact that the communication device has the predetermined capability, When a frequency resource in the fourth frequency band is allocated, a changing means for changing the frequency band to be used to the fourth frequency band, The system includes communication means for communicating with other communication devices using specified frequency resources. A communication device characterized by the following features.

9. The communication means communicates with the other communication device using Orthogonal Frequency Division Multiple Access (OFDMA). The communication device according to feature 8.

10. When an instruction is received to change the frequency band used by the communication device from the second frequency band to the fourth frequency band, The modification means changes the frequency band used by the communication device from the second frequency band to the fourth frequency band. The aforementioned communication means is The response to the instruction from the other communication device is transmitted in the fourth frequency band. Data communication with the aforementioned other communication device is performed in the fourth frequency band. The communication device according to feature 8.

11. The notification means notifies the capability information, which includes information for identifying the range on the frequency axis that the communication device can set as the fourth frequency band. The communication device according to feature 8.

12. The notification means notifies the capability information, which includes information for specifying the time required for the communication device to move from a state in which it is communicating in the second frequency band to a state in which it is capable of communicating in the fourth frequency band. The communication device according to feature 8.

13. The notification means notifies the capability information using a frame that includes a UHR Capabilities element. The communication device according to feature 8.

14. The specified information includes information for identifying a frequency band containing the frequency resources allocated to the communication device, and information for uniquely identifying the frequency resources allocated to the communication device within that frequency band. The communication device according to feature 8.

15. A control method performed by a communication device capable of communicating with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, In the first frequency band of the first bandwidth used by the communication device for communication, there exists a second frequency band determined based on a second bandwidth that the other communication device can handle, and a third frequency band other than the second frequency band. The control method described above is In frequency division multiplexing communication performed by the communication device with a plurality of devices including the other communication device, when the frequency resources of the second frequency band are allocated to a device other than the other communication device, the acquisition step of capability information obtained from the other communication device indicating whether or not the other communication device has the capability to change the frequency band used from the second frequency band to a fourth frequency band of the second bandwidth including a part of the third frequency band, and perform the frequency division multiplexing communication; The process includes allocating frequency resources to the aforementioned other communication device and performing communication with said other communication device, The aforementioned communication process is, Based on the fact that the other communication device does not have the predetermined capability, a frequency resource from the second frequency band is allocated to the other communication device without changing the frequency band used by the other communication device. Based on the fact that the other communication device has the predetermined capabilities, frequency resources are allocated to the other communication device from the second frequency band, or from the fourth frequency band by changing the frequency band used by the other communication device to the fourth frequency band. A communication method characterized by the following features.

16. A control method performed by a communication device capable of communicating with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, In the first frequency band of the first bandwidth used for communication by the other communication device, there exists a second frequency band determined based on a second bandwidth that the communication device can handle, and a third frequency band other than the second frequency band. The control method described above is In frequency division multiplexing communication performed by the other communication device between the communication device and a plurality of other devices, if the frequency resources of the second frequency band are allocated to a device other than the communication device, the communication device notifies the other communication device of capability information indicating whether or not it has the capability to change the frequency band used from the second frequency band to a fourth frequency band of the second bandwidth that includes a part of the third frequency band, and perform the frequency division multiplexing communication; From the aforementioned other communication device, The frequency resources within the second frequency band allocated based on the fact that the communication device does not have the predetermined capability, An acquisition step of acquiring specific information that identifies a frequency resource in the second frequency band or a frequency resource in the fourth frequency band, which is allocated based on the fact that the communication device has the predetermined capability, When a frequency resource within the fourth frequency band is allocated, the process includes a change step of changing the frequency band to be used to the fourth frequency band, The system includes a communication step of communicating with the other communication device using specified frequency resources. A control method characterized by the following:

17. A program for causing a computer to function as each of the means of the communication device described in claim 1.

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