Communication device, communication method, and program

Abstract

Ensure that multiple access points are properly configured to send data to the terminal in parallel. [Solution] A communication device that constructs a first Basic Service Set (BSS) communicates a radio frame having a physical layer (PHY) preamble and a data field. The preamble includes an Extremely High Throughput (EHT) Signal Field (EHT-SIG-A). EHT-SIG-A includes a subfield that sets the BSS color, and when the communication device and the first other communication device cooperate to transmit a radio frame to the second other communication device, the value of this subfield is set based on the BSS color of the second BSS to which the second other communication device belongs, without changing the BSS color used in the first BSS.

Description

Technical Field

[0001] The present invention relates to communication control technology in a wireless LAN.

Background Art

[0002] As a communication standard for a wireless LAN (Wireless Local Area Network), the IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard is known. In the IEEE 802.11ax standard, which is the latest standard in the IEEE 802.11 standard series, by using OFDMA (Orthogonal Frequency Division Multiple Access), in addition to high peak throughput, an improvement in communication speed under congested conditions is achieved (see Patent Document 1).

[0003] Currently, for further throughput improvement, as a successor standard to IEEE 802.11ax, a Study Group called IEEE 802.11EHT (Extremely High Throughput) has been formed. In EHT, in order to achieve throughput improvement, a Multi-AP Coordination configuration is being considered in which a plurality of spatially distributed access points (APs) cooperate to transmit data to a single STA (Station).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The IEEE 802.11ax standard specifies the use of identification information called BSS (Basic Service Set) color. When a communication device receives a wireless frame with the same BSS color as the AP to which it is connected, it treats that wireless frame as an Intra-BSS frame. On the other hand, while the use of a Multi-AP Coordination configuration is being considered in IEEE 802.11EHT as described above, it is not yet clear how the BSS color should be set in this case.

[0006] This invention provides a method for appropriately configuring multiple access points to transmit data to a terminal in parallel. [Means for solving the problem]

[0007] A communication device according to one aspect of the present invention is a communication device comprising: construction means for constructing a first Basic Service Set (BSS); and transmission means for transmitting a wireless frame having a physical layer (PHY) preamble and a data field, wherein the preamble includes: a Legacy Short Training Field (L-STF); a Legacy Long Training Field (L-LTF) positioned immediately after the L-STF in the wireless frame; a Legacy Signal Field (L-SIG) positioned immediately after the L-LTF in the wireless frame; an Extremely High Throughput (EHT) Signal Field (EHT-SIG-A) positioned after the L-SIG in the wireless frame; an EHT Short Training Field (EHT-STF) positioned after the EHT-SIG-A in the wireless frame; and an EHT Long Training Field (EHT-LTF) positioned immediately after the EHT-STF in the wireless frame, wherein the EHT-SIG-A is part of the BSS. The system includes a subfield for setting a color, and when the communication device and a first other communication device cooperate to transmit the wireless frame to a second other communication device, the value of the subfield is set based on the BSS color of the second BSS to which the second other communication device belongs, without changing the BSS color used in the first BSS. [Effects of the Invention]

[0008] According to the present invention, it is possible to properly configure multiple access points to transmit data to a terminal in parallel. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an example of a network configuration. [Figure 2] This figure shows an example of the hardware configuration for AP and STA. [Figure 3]This figure shows an example of the functional configuration of AP and STA. [Figure 4] This figure shows an example of the PHY frame structure for EHT SU PPDU. [Figure 5] This figure shows an example of the PHY frame structure of EHT ER PPDU. [Figure 6] This figure shows an example of the PHY frame structure for EHT MU PPDU. [Figure 7] This figure shows an example of the processing flow executed in a network. [Figure 8] This diagram shows an example of the processing flow executed in AP. [Modes for carrying out the invention]

[0010] 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.

[0011] (Network configuration) Figure 1 shows an example of the configuration of a wireless communication network according to this embodiment. This wireless communication network is composed of access points (AP102, AP104) and terminals (STA103, STA105), each of which is an IEEE 802.11 EHT (Extremely High Throughput) device. Hereafter, when not referring to a specific device, access points may be referred to as "AP" and stations as "STA" without reference numbers. In Figure 1, a wireless communication network including two APs and two STAs is shown as an example, but the number of these communication devices may be, for example, three or more. In Figure 1, the communication range of the network formed by AP102 and AP104 is indicated by circle 101. This communication range may cover a wider area or only a narrower area. Also, in Figure 1, STAs compliant with the IEEE 802.11 EHT standard are shown, but there may be STAs that only support older standards (legacy standards) than the IEEE 802.11 EHT standard. EHT can also be interpreted as an abbreviation for Extreme High Throughput.

[0012] In this example, AP102 and AP104 are assumed to be able to receive signals transmitted by the other AP. The connection configuration is not particularly limited, and AP102 and AP104 may be connected by wire or wirelessly. AP102 and AP104 support the IEEE 802.11EHT Multi-AP Coordination configuration and are assumed to be able to cooperate with each other to transmit data in parallel to a single STA. For example, STA105 can send and receive wireless frames in parallel with AP102 and AP104, which are operating in cooperation. STA105 may have, for example, multiple wireless LAN control units and be configured to send and receive wireless frames with multiple APs using different wireless channels. STA105 may have a single physical control unit capable of processing multiple frames received in parallel via multiple wireless channels. That is, STA105 has a configuration that allows it to logically process multiple wireless communications in parallel using one or more physical control units.

[0013] (Device configuration) Figure 2 shows the hardware configuration of APs (AP102, AP104) and STAs (STA103, STA105). These communication devices, as an example of their hardware configuration, include a storage unit 201, a control unit 202, a functional unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207.

[0014] The memory unit 201 is composed of both ROM and RAM, or either one, and stores various information such as programs for performing various operations described later, and communication parameters for wireless communication. In addition to memory such as ROM and RAM, storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs may be used as the memory unit 201.

[0015] The control unit 202 is composed of, for example, a processor such as a CPU or MPU, an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), etc. Here, CPU is the acronym for Central Processing Unit, and MPU is the acronym for Micro Processing Unit. The control unit 202 controls the entire device by executing the program stored in the storage unit 201. Note that the control unit 202 may control the entire device by collaborating with the program stored in the storage unit 201 and the OS (Operating System).

[0016] Also, the control unit 202 controls the functional unit 203 to execute predetermined processes such as imaging, printing, projection, etc. The functional unit 203 is hardware for the device to execute predetermined processes. For example, when the device is a camera, the functional unit 203 is an imaging unit and performs imaging processing. Also, for example, when the device is a printer, the functional unit 203 is a printing unit and performs printing processing. Also, for example, when the device is a projector, the functional unit 203 is a projection unit and performs projection processing. The data processed by the functional unit 203 may be data stored in the storage unit 201, or may be data communicated with other APs or STAs via the communication unit 206 described later.

[0017] The input unit 204 receives various operations from the user. The output unit  205 performs various outputs to the user. Here, the output by the output unit 205 includes, for example, at least one of display on the screen, voice output by the speaker, vibration output, etc. Note that both the input unit 204 and the output unit 205 may be realized by one module such as a touch panel.

[0018] The communication unit 206 controls wireless communication compliant with the IEEE 802.11 standard series and IP communication. In this embodiment, the communication unit 206 can perform processing compliant with at least the IEEE 802.11 EHT standard. The communication unit 206 also controls the antenna 207 to transmit and receive wireless signals for wireless communication. The device communicates content such as image data, document data, and video data with other communication devices via the communication unit 206. The antenna 207 is, for example, an antenna capable of transmitting and receiving at least one of the sub-GHz band, 2.4GHz band, 5GHz band, and 6GHz band. The frequency bands (and their combinations) that the antenna 207 can handle are not particularly limited. The antenna 207 may be a single antenna or a set of two or more antennas for MIMO (Multi-Input and Multi-Output) transmission and reception. Although Figure 2 shows a single antenna 207, it may include, for example, two or more antennas (two or more sets) each capable of handling different frequency bands. Antenna 207 is configured to support Distributed Coordination communication according to the IEEE 802.11EHT standard. For example, the AP is configured to enable D-MIMO (Distributed MIMO) transmission for JTX (Joint Transmission).

[0019] Note that JTX is an element for implementing the Multi-AP Coordination function newly introduced from IEEE802.11EHT, which refers to the situation where multiple APs cooperate to transmit data to one STA in parallel. The Multi-AP Coordination function is a function in which multiple APs cooperate to improve the throughput and signal strength of transmission and reception on the STA side. As the wireless technology at this time, D-MIMO can be used. D-MIMO is a technology in which multiple APs communicate with one STA at the same time and on the same frequency channel (for example, the same RU (Resource Unit) of OFDMA (Orthogonal Frequency Division Multiple Access)). According to D-MIMO, high-speed communication can be realized by improving the spatial utilization efficiency. The minimum configuration of D-MIMO is M-AP (Master AP), S-AP (Slave AP), and STA. In this case, under the control of the M-AP, two APs, the M-AP and the S-AP, cooperate to transmit wireless frames to one STA in parallel (simultaneously).

[0020] Fig. 3 shows a functional configuration example of the APs (AP102, AP104). As an example, the AP has a wireless LAN control unit 301, a frame generation unit 302, a BSS color setting unit 303, a UI control unit 304, a storage unit 305, and an antenna 306.

[0021] The wireless LAN control unit 301 is configured to include circuits for sending and receiving wireless signals with other wireless LAN devices (e.g., other APs and STAs) and programs for controlling them. The wireless LAN control unit 301 performs wireless LAN communication control, such as transmitting frames generated by the frame generation unit 302 and receiving wireless frames from other wireless LAN devices, in accordance with the IEEE 802.11 standard series. The frame generation unit 302 generates wireless frames to be transmitted by the wireless LAN control unit 301 based on data to be transmitted to the STA, for example, received from another AP. The frame generation unit 302 also generates wireless frames containing data to be transmitted to the STA by other APs, and trigger frames (JTX TF) that indicate the timing at which the wireless frames containing that data should be transmitted to the STA.

[0022] The BSS color setting unit 303 sets the BSS color of the wireless frame. For example, when the device (AP102 or AP104) constructs a BSS (Basic Service Set), the BSS color setting unit 303 sets the BSS color used in that BSS. The BSS color setting unit 303 then sets the value of that BSS color for wireless frames transmitted to STAs connected to the device. On the other hand, when the BSS color setting unit 303 transmits data via JTX to an STA connected to another AP, it sets the BSS color used in the BSS constructed by that other AP for wireless frames transmitted to that STA. In other words, when the BSS color setting unit 303 transmits wireless frames via JTX to an STA connected to a different AP than the device itself, it uses the BSS color of the other AP rather than the BSS color used in the BSS constructed by the device itself. This makes it possible to ensure that multiple wireless frames received by an STA are wireless frames with the BSS color used in the BSS to which the STA is connected set. Therefore, the STA can treat multiple wireless frames received from multiple APs as all Intra-BSS frames. On the other hand, the BSS color setting unit 303 sets the BSS color of the BSS constructed by the device for wireless frames other than JTX, so an STA connected to another AP can treat those wireless frames as Inter-BSS frames. The STA can perform different controls depending on whether the received wireless frame is an Intra-BSS frame or an Inter-BSS frame. For example, the STA can transmit a wireless frame if the received power of the wireless frame does not exceed a predetermined value, but the predetermined value for Inter-BSS frames can be set to a higher value than the predetermined value for Intra-BSS frames. As a result, even if a wireless frame is received with power exceeding the predetermined value for Intra-BSS frames, if that wireless frame is an Inter-BSS wireless frame, the STA may still have an opportunity to transmit.Therefore, by having an AP use a different BSS color from other APs when not JTX, it is possible to increase the communication opportunities for STAs connected to other APs, thereby improving the overall frequency utilization efficiency of the system.

[0023] The UI control unit 304 includes hardware related to a user interface (UI), such as a touch panel or buttons, for receiving operations on the AP by a user (not shown) of the AP, and a program to control them. The UI control unit 304 also has functions for presenting information to the user, such as displaying images or outputting sound. The storage unit 305 includes storage devices such as ROM (Read Only Memory) and RAM (Random Access Memory) for storing programs executed by the AP and various data.

[0024] Furthermore, the STA has the functionality of a general STA. However, the STA may also have the functionality to receive wireless frames transmitted in a Multi-AP Coordination configuration.

[0025] (Frame structure) Figures 4 to 6 illustrate examples of PPDU (Physical Layer (PHY) Protocol Data Unit) structures compliant with the IEEE 802.11 EHT standard. Figure 4 shows an example of an EHT SU (Single User) PPDU for single-user communication, and Figure 5 shows an example of an EHT MU (Multi User) PPDU for multi-user communication. Figure 6 shows an example of an EHT ER (Extended Range) PPDU for long-distance transmission. The EHT ER PPDU is used when the communication range needs to be extended in communication between an AP and a single STA. Note that the fields of the PPDU do not necessarily have to be in the order shown in Figures 4 to 6, and it may include new fields not shown in Figures 4 to 6.

[0026] The PPDU includes the fields STF (Short Training Field), LTF (Long Training Field), and SIG (Signal Field). As shown in Figure 4, the beginning of the PPDU has L(Legacy)-STF401, L-LTF402, and L-SIG403 to ensure backward compatibility with the IEEE 802.11a / b / g / n / ax standards. The frame formats in Figures 5 and 6 also include L-STF (L-STF501 and L-STF601), L-LTF (L-LTF502 and L-LTF602), and L-SIG (L-SIG503 and L-SIG603). Note that L-LTF is placed immediately after L-STF, and L-SIG is placed immediately after L-LTF. Furthermore, in the configurations shown in Figures 4 to 6, an RL-SIG (Repeated L-SIG, RL-SIG404, RL-SIG504, RL-SIG604) is included immediately after the L-SIG. The RL-SIG field transmits the content of the L-SIG repeatedly. The RL-SIG allows the receiver to recognize that the PPDU conforms to standards later than IEEE 802.11ax, and may be omitted in IEEE 802.11EHT in some cases. Alternatively, a field may be provided to allow the receiver to recognize that the PPDU conforms to IEEE 802.11EHT instead of the RL-SIG.

[0027] L-STF401 is used for detecting physical layer (PHY) frame signals, automatic gain control (AGC), and timing detection. L-LTF402 is used for high-precision synchronization of frequency and time, and acquisition of channel state information (CSI). L-SIG403 is used to transmit control information including data transmission rate and PHY frame length information. Legacy equipment conforming to IEEE 802.11a / b / g / n / ax standards can decode the above-mentioned legacy fields.

[0028] Each PPDU further includes an EHT-SIG (EHT-SIG-A405, EHT-SIG-A505, EHT-SIG-B506, EHT-SIG-A605) for transmitting control information for the EHT, located immediately after the RL-SIG. Each PPDU also has an STF (EHT-STF406, 507, 606) and an LTF (EHT-LTF407, 508, 607) for the EHT. Following these control fields, each PPDU has data fields 408, 509, 608 and Packet extension fields 409, 710, 609. The fields from L-STF to EHT-LTF in each PPDU are called the PHY preamble.

[0029] Figures 4 to 6 show an example of a PPDU that ensures backward compatibility. However, if backward compatibility is not required, legacy fields may be omitted, for example. In this case, EHT-STF or EHT-LTF may be used instead of L-STF and L-LTF to establish synchronization. In this case, one of the EHT-STF or EHT-LTF fields following the EHT-SIG field may be omitted.

[0030] The EHT-SIG-A405 and EHT-ER PPDU, respectively, contain EHT-SIG-A405 and EHT-SIG-A605, which are necessary for receiving the PPDU, as shown in Tables 1 and 2 below. EHT-SIG-A1 includes a 6-bit "BSS color" subfield. Similarly, the EHT-SIG-A505 of the EHT MU PPDU in Figure 5 also contains EHT-SIG-A1 and EHT-SIG-A2, which are necessary for receiving the PPDU, as shown in Tables 3 and 4 below. In this PPDU as well, EHT-SIG-A1 includes a 6-bit "BSS color" subfield. Note that the configurations in Tables 1 to 4 are merely examples, and other information may be included in the EHT-SIG field, or some of the information shown in these tables may be omitted from the EHT-SIG field.

[0031] [Table 1]

[0032] [Table 2]

[0033] [Table 3]

[0034] [Table 4]

[0035] (Process flow) Next, we will explain the processing flow performed by the AP as described above, and examples of processing flows performed in the wireless communication network, using Figures 7 and 8. Figure 7 shows an example of a processing flow in the wireless communication network, and Figure 8 shows an example of a processing flow performed by AP102 and AP104.

[0036] First, AP102 constructs the first BSS (BSS1) (F701, S801). In this embodiment, it is assumed that BSS1 is configured to use BSS color1. AP104 then constructs the second BSS (BSS2) (F702, S801). In this embodiment, it is assumed that BSS2 is configured to use BSS color2, which is different from BSS color1. Each AP broadcasts an IEEE802.11 Beacon at regular intervals and accepts connection requests from STAs, thereby mediating communication between STAs or between STAs and DS (Distribution System).

[0037] AP102 performs a connection procedure with STA103 and transitions to a connected state (F703). Similarly, AP104 performs a connection procedure with STA105 and transitions to a connected state (F704). In this connection procedure, as in the case of IEEE802.11ax, operational status information is notified from the AP to the STA. This operational status information includes the BSS color value. As mentioned above, the BSS color is 6 bits of information that identifies the BSS included in the physical layer (PHY) preamble. The BSS color value allows the STA to determine whether the received wireless frame is a frame of the BSS to which it belongs (intra-BSS) or a frame of a BSS to which it does not belong (inter-BSS).

[0038] AP102 can transmit a wireless frame to STA103 (F705). This wireless frame is a PPDU as shown in one of Figures 4 to 6, and the BSS color subfield stores a value indicating BSS color 1 used in BSS1. Similarly, AP104 can transmit a wireless frame to STA105 (F706). This wireless frame is also a PPDU as shown in one of Figures 4 to 6, and the BSS color subfield stores a value indicating BSS color 2 used in BSS2. As shown in the table above, the BSS color subfield is the 9th to 14th bits (B8 to B13) of EHT-SIG-A1 in the case of EHT SU PPDU and EHT ER PPDU. Also, the BSS color subfield is the 6th to 11th bits (B5 to B10) of EHT-SIG-A1 in the case of EHT MU PPDU.

[0039] Subsequently, AP102 and AP104 decide to cooperate and transmit data to a common STA in parallel. For example, if AP104 detects that there is a large amount of data to be sent to STA105, it may decide to cooperate with another AP nearby, such as AP102, to transmit the data to STA105 in parallel. Also, AP102 or AP104 may decide to prepare for cooperative transmission with other APs in anticipation of future large-volume data communications, even if there are no plans for large-volume data communications to a specific STA. If it is decided that cooperative transmission by multiple APs will be performed or that preparations for such transmission will be made, AP102 and AP104 will negotiate for JTX (Joint Transmission) (F707, S802). In the following, the negotiation for JTX may be simply referred to as "negotiation". During the negotiation, the AP performing the negotiation may decide whether to operate in the role of M-AP or S-AP. Here, it is decided that AP102 will operate as an M-AP (YES in F708 and S803), and AP104 will operate as an S-AP (NO in F709 and S803). In this negotiation, it may also be decided which AP will associate with the STA that will perform JTX.

[0040] After the negotiation is complete, AP104, which is the S-AP, notifies AP102, which is the M-AP, of the information of STA105 connected to its device and the information of BSS color2 used in BSS2 constructed by its device (F710, S804, S811). Here, the STA information may include the MAC (Media Access Control) address information of that STA. Note that this information may also be notified from the S-AP to the M-AP at other times, such as when it is exchanged between APs at the time of negotiation. AP102 may also notify AP104 of the information of STA103 connected to its device and the information of BSS color1 used in BSS1 constructed by its device. Furthermore, if AP102 and AP104 perform JTX to send data to a specific STA, the AP connected to that STA may notify the other AP of the STA's information and BSS color information. However, since M-AP can specify the STA and BSS color to be transmitted in the transmission of data to be sent or in the JTX trigger frame, as described later, it is not necessary for M-AP to provide information to S-AP at this point.

[0041] Subsequently, AP102 notifies AP104, which is operating as an S-AP, of the start of JTX mode (F711, S805, S812). Then, when data to be transmitted to STA105 is generated (YES in S806), AP102 transmits that data to AP104 (F712, S807, S813). Since AP104 is operating in JTX mode, it does not immediately transmit the received data to STA105, but temporarily holds the received data.

[0042] Furthermore, when transmitting the data to be transmitted from M-AP to S-AP, information on the BSS color to be used may be notified from M-AP to S-AP. In this embodiment, since data is transmitted to STA105 by JTX, BSS color2 used by AP104, to which STA105 is connected, may be notified as information on the BSS color to be used. However, if the BSS color to be used matches the BSS color used in S-AP, or if the BSS color used by JTX is known in advance, the BSS color information does not need to be notified from M-AP to S-AP. In other words, when M-AP transmits data by JTX to an STA connected to S-AP, or if BSS color information has been exchanged with the STA to which data is transmitted by JTX, the BSS color information does not need to be notified to S-AP. For example, when data is transmitted by JTX to STA103, BSS color1 may be notified from AP102 to AP104 as information on the BSS color to be used. Furthermore, when data is transmitted via the aforementioned PPDU, the PPDU includes a PHY preamble that notifies the BSS color, and therefore, information about the BSS color to be used is naturally notified. In this case, the S-AP receives a wireless frame with a BSS color different from the one it is using, but because it is operating in JTX mode, it does not discard the data in this wireless frame.

[0043] After transmitting and receiving the data to be transmitted, AP102 sends a JTX trigger frame (TF) to AP104 to cause AP104 to transmit a wireless frame containing this data (F713, S808, S814). AP102 can use the JTX TF to instruct AP104 to transmit a wireless frame to STA105 and to specify the timing of that transmission. Then, AP102 and AP104 transmit data to STA105 in parallel at the timing specified by the JTX TF (YES in S809) (F714, F715, S810). The transmission timing may be after a predetermined time (SIFS, Short Inter Frame Space) has elapsed since the transmission and reception of the JTX TF. In this case, the transmission timing is indicated by the transmission and reception of the JTX TF itself. In this case, the JTX TF may be transmitted at a timing corresponding to when AP102 and AP104 should transmit a wireless frame to STA105. Furthermore, the JTX TF frame may include information specifying the transmission timing. In this case, AP102 and AP104 can determine when to transmit the wireless frame using the specified transmission timing and their own internal timers or clocks. In this way, AP102 and AP104 can transmit wireless frames synchronously using the JTX TF.

[0044] In this data transmission, the BSS color used by the BSS (AP to which the STA is connected) to which the data-transmitting STA belongs is set in the PHY preamble within the wireless frame. In the example in Figure 7, BSS color 2, used by BSS 2 to which the data-transmitting STA 105 belongs, is set within the wireless frame. That is, AP 104 transmits the wireless frame using the BSS color 2 that it uses itself, while AP 102 transmits the wireless frame using a different BSS color 2 than the BSS color 1 that it uses itself. However, the BSS color of BSS 1 constructed by AP 102 is not changed from BSS color 1. In other words, AP 102 does not change the BSS color of the BSS constructed by its own device, but when transmitting data via JTX, it sets the BSS color used by the BSS to which the data-receiving STA belongs in the wireless frame before transmitting. At this time, AP 102 can transmit data to the STA (STA 103) connected to its own device even while operating in JTX mode. In this case, AP102 can set the BSS color 1 used by the BSS1 constructed by its own device in the wireless frame and transmit data. That is, when AP102 is operating in JTX mode, it sets the BSS color of the BSS to which the STA belongs in the wireless frame and transmits it. The same applies to AP104. That is, AP104 uses BSS color 2 in the BSS2 constructed by its own device, but if AP102 instructs it to send data to STA103 via JTX, for example, it can send a wireless frame with BSS color 1 set to STA103. Note that in this case, AP104 does not change the BSS color of BSS2.

[0045] In this way, each AP does not change the BSS color in the BSS it has established, and therefore does not instruct the connected STA to change the BSS color. As a result, unnecessary changes to the STA's settings are avoided, and for example, an increase in the STA's power consumption can be suppressed. On the other hand, during JTX, the BSS color in the PHY preamble of the wireless frame is set to match the BSS to which the STA belongs, so the STA can receive wireless frames during JTX without changing its BSS color settings.

[0046] 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.

[0047] 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]

[0048] 102, 104: AP, 103, 105: STA, 301: Wireless LAN control unit, 302: Frame generation unit, 303: BSS color setting unit, 304: UI control unit, 305: Memory unit

Claims

1. A means for constructing the first Basic Service Set (BSS), A transmission means for transmitting a wireless frame having a physical layer (PHY) preamble and data field, A communication device having, The aforementioned preamble is, Legacy Short Training Field (L-STF), In the wireless frame, the Legacy Long Training Field (L-LTF) is positioned immediately after the L-STF, In the aforementioned wireless frame, a Legacy Signal Field (L-SIG) is positioned immediately after the L-LTF, In the aforementioned wireless frame, the Extremely High Throughput (EHT) Signal Field (EHT-SIG-A) is placed after the L-SIG, In the aforementioned wireless frame, the EHT Short Training Field (EHT-STF) is placed after the EHT-SIG-A, In the aforementioned wireless frame, the EHT Long Training Field (EHT-LTF) is positioned immediately after the EHT-STF, Includes, The aforementioned EHT-SIG-A includes a subfield for setting the BSS color, When the aforementioned communication device and the first other communication device cooperate to transmit the wireless frame to the second other communication device, the value of the subfield is set based on the BSS color of the second BSS to which the second other communication device belongs, without changing the BSS color used in the first BSS. A communication device characterized by the following features.

2. The communication device according to claim 1, characterized in that, if the second BSS is a third BSS constructed by the first other communication device, the BSS color used in the third BSS is set as the value of the subfield.

3. The communication device according to claim 2, characterized in that the communication device acquires information on the BSS color of the third BSS from the first other communication device.

4. The communication device according to claim 2 or 3, characterized in that, when the second BSS is the third BSS, the communication device obtains information of the second other communication device from the first other communication device.

5. The communication device according to any one of claims 1 to 4, characterized in that, if the second BSS is the first BSS, the BSS color used in the first BSS is set as the value of the subfield.

6. The communication device according to any one of claims 1 to 5, characterized in that the communication device notifies the other first communication device of the BSS color information of the first BSS.

7. The communication device according to claim 5, characterized in that, when the second BSS is the first BSS, the communication device notifies the first other communication device of the information of the second other communication device.

8. The communication device according to any one of claims 1 to 7, characterized in that while the communication device is operating in a mode in which it transmits the wireless frame in cooperation with the first other communication device, the value of the subfield is set based on the BSS color of the BSS to which the device to which the wireless frame is to be transmitted belongs.

9. The communication device according to claim 8, characterized in that, while the communication device is not operating in the mode, the value of the subfield is set based on the BSS color of the first BSS.

10. The communication device according to any one of claims 1 to 9, characterized in that the communication device and the first other communication device are access points compliant with IEEE 802.11 EHT, and the second other communication device is a station compliant with IEEE 802.11 EHT.

11. A communication method performed by a communication device that constructs a first Basic Service Set (BSS), The process includes transmitting a radio frame having a physical layer (PHY) preamble and data fields, The aforementioned preamble is, Legacy Short Training Field (L-STF), In the wireless frame, the Legacy Long Training Field (L-LTF) is positioned immediately after the L-STF, In the aforementioned wireless frame, a Legacy Signal Field (L-SIG) is positioned immediately after the L-LTF, In the aforementioned wireless frame, the Extremely High Throughput (EHT) Signal Field (EHT-SIG-A) is placed after the L-SIG, In the aforementioned wireless frame, the EHT Short Training Field (EHT-STF) is placed after the EHT-SIG-A, In the aforementioned wireless frame, the EHT Long Training Field (EHT-LTF) is positioned immediately after the EHT-STF, Includes, The aforementioned EHT-SIG-A includes a subfield for setting the BSS color, When the aforementioned communication device and the first other communication device cooperate to transmit the wireless frame to the second other communication device, the value of the subfield is set based on the BSS color of the second BSS to which the second other communication device belongs, without changing the BSS color used in the first BSS. A communication method characterized by the following features.

12. A program for causing a computer to function as one of the means of a communication device according to any one of claims 1 to 10.

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