Communication device, control method, and program

Abstract

To allow a wireless LAN terminal to recognize whether the wireless LAN terminal is communicating in cooperation with a plurality of access points.SOLUTION: A communication device conforming to the IEEE802.11 series of standards transmits a wireless frame having a preamble and a data field of a physical layer (PHY). The preamble includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), and a signal field arranged at least after the L-SIG. The signal field includes a field including information indicating that the communication device and another communication device different from the communication device transmit data in cooperation with each other.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] With the increase in the amount of data being communicated in recent years, the development of communication technologies such as wireless LANs (Local Area Networks) is progressing. The IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard series is known as a major communication standard for wireless LANs. The IEEE 802.11 standard series includes standards such as IEEE 802.11a / b / g / n / ac / ax. For example, the latest standard, IEEE 802.11ax, uses OFDMA (orthogonal frequency division multiple access) to standardize a technology that improves communication speeds under congested conditions in addition to a high peak throughput of up to 9.6 gigabits per second (Gbps) (see Patent Document 1).

[0003] Meanwhile, in order to further improve throughput, a study group called IEEE802.11EHT (Extremely High Throughput) has been formed as a successor standard to IEEE802.11ax. In order to achieve higher throughput, EHT is considering allocating transmission data for a single STA (Station) to multiple spatially distributed access points (APs), which then cooperate to transmit the data to the STA. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-050133 A Summary of the Invention [Problem to be solved by the invention]

[0005] It may be useful for a STA to recognize whether it is receiving frames from a single AP or multiple APs. On the other hand, in conventional standards, it is assumed that a STA communicates with a single AP, and it is not assumed that the STA communicates in cooperation with multiple APs. Therefore, there is no mechanism for a STA to recognize that frames are being transmitted in cooperation from multiple APs.

[0006] The present invention provides a technique that enables a terminal of a wireless LAN to recognize whether or not it is communicating in cooperation with a plurality of access points. [Means for solving the problem]

[0007] A communication device according to one embodiment of the present invention is a communication device that complies with the IEEE 802.11 standard series and has a transmission means for transmitting a wireless frame having a physical layer (PHY) preamble and a data field, the preamble including an L-STF (Legacy Short Training Field), an L-LTF (Legacy Long Training Field), an L-SIG (Legacy Signal Field), and a signal field arranged at least after the L-SIG, and the signal field includes a field including information indicating that the communication device and another communication device different from the communication device are transmitting data in cooperation. Effect of the Invention

[0008] According to the present invention, it is possible to recognize whether a terminal of a wireless LAN is communicating in cooperation with a plurality of access points. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 illustrates an example of a network configuration. [Diagram 2] FIG. 2 is a diagram illustrating an example of a functional configuration of an AP. [Diagram 3]FIG. 2 illustrates an example of a hardware configuration of an AP. [Figure 4] FIG. 11 is a diagram illustrating an example of a flow of processing executed in an AP. [Diagram 5] FIG. 1 is a diagram illustrating an example of a flow of processing executed in a network. [Figure 6] A figure showing an example of a PHY frame structure of an EHT SU PPDU. [Figure 7] A diagram showing an example of a PHY frame structure of an EHT ER PPDU. [Figure 8] FIG. 2 is a diagram illustrating an example of a PHY frame structure of an EHT MU PPDU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] (Network Configuration) FIG. 1 shows an example of the configuration of a wireless communication network according to the present embodiment. This wireless communication network includes access points (AP102, AP103, AP104) and terminals (STA105, STA106, STA107), each of which is an EHT (Extremely High Throughput) device. All of these devices comply with IEEE802.11EHT (Extreme High Throughput) and are configured to be able to perform wireless communication that complies with a standard established before the IEEE802.11EHT standard. The name IEEE802.11EHT is provided for convenience, and may be called a different name when the standard is finalized, but this specification and the appended claims are intended to cover all standards that can support the processing described below. In the following, when a specific device is not being referred to, an access point may be called an "AP" and a station may be called an "STA" without a reference number. In addition, FIG. 1 shows a wireless communication network including three APs and three STAs as an example, but the number of these communication devices may be two or less, or may be four or more. In FIG. 1, a communication range of a network formed by AP 102, AP 103, and AP 104 is shown by a circle 101. This communication range may cover a wider range, or may cover only a narrower range. In addition, in FIG. 1, an STA supporting EHT is shown, but there may be an STA supporting only a standard (legacy standard) of a generation earlier than EHT. In addition, EHT may be interpreted as an acronym for Extreme High Throughput.

[0012] In this example, it is assumed that the AP103 and AP104 can receive a signal transmitted by the AP102, and that the AP102 can receive a signal transmitted by the AP103 and AP104. However, the connection form is not particularly limited, and the AP102 and the AP103 and AP104 may be connected by wire or wirelessly. The AP103 and AP104 may or may not be able to transmit and receive signals to and from each other. The AP102 to AP104 are capable of configuring a Multi-AP Coordination system of IEEE802.11EHT. That is, it is assumed that the AP102 to AP104 support a configuration in which multiple APs communicate with one STA in coordination as specified by IEEE802.11EHT. For example, the STA105 can transmit and receive wireless frames in parallel with the AP103 and AP104 that operate in coordination. The STA105 may be configured to have, for example, multiple wireless LAN controllers and to be able to transmit and receive wireless frames between multiple APs using different wireless channels. The STA105 may also have one physical controller capable of processing multiple frames received in parallel via multiple wireless channels. That is, the STA105 has a configuration that allows it to logically process multiple wireless communications in parallel using one or more physical control devices.

[0013] Here, APs such as AP103 and AP104 that directly transmit and receive signals with each STA are called slave access points (S-APs). Also, APs such as AP102 that can transmit and receive frames with each STA at least indirectly by issuing instructions to AP103 and AP104 are called master access points (hereinafter, M-APs). Note that the M-AP may directly transmit and receive signals with the STA105. For example, the AP102 may operate as both the M-AP and the S-AP. In this case, for example, the AP102 may transmit and receive wireless frames between itself and the STA105 by issuing instructions to the AP103 or AP104 to transmit and receive wireless frames with the STA. Note that the M-AP may transmit data to be transmitted to the S-AP when it transmits a wireless frame from the S-AP. However, this is not limited thereto, and the S-AP may directly obtain data to be transmitted from the Internet, for example. In addition, the M-AP may receive data that the S-AP received from the STA from the S-AP, but the S-AP may also forward the data received from the STA to the STA's peer device without forwarding it to the M-AP.

[0014] Any AP in the same network can operate as an M-AP, and it may be determined by some criteria which AP will operate as an M-AP. An M-AP may only perform the role of an M-AP, such as sending instructions to each AP, without operating as an AP, such as transmitting beacons. Each AP may have multiple wireless LAN controllers and operate as multiple S-APs. An M-AP may be realized as a logical function, and one physical AP may operate as one or more S-APs while operating as an M-AP.

[0015] In the following, an example of the configuration and process flow of the AP 103 and the AP 104 as APs (S-APs) that directly transmit wireless frames to STAs will be described.

[0016] (AP configuration) 2 shows the functional configuration of AP 103. AP 104 also has similar functions. AP 103 has, as an example, two sets of functional units (wireless LAN control unit 201 and antenna 207, and wireless LAN control unit 206 and antenna 208) for performing wireless LAN communication. However, the number of wireless LAN control units that AP 103 has is not limited to two, and may be one or three or more. AP 103 further has a frame generation unit 202, an M-AP signal analysis unit 203, a UI control unit 204, and a storage unit 205.

[0017] The wireless LAN control unit 201 and the wireless LAN control unit 206 are configured to include circuits for transmitting 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 201 and the wireless LAN control unit 206 execute wireless LAN communication control, such as transmitting frames generated by the frame generation unit 202 and receiving wireless frames from other wireless LAN devices, in accordance with the IEEE802.11 standard series. The frame generation unit 202 generates wireless frames to be transmitted by the wireless LAN control unit 201 and the wireless LAN control unit 208 based on the contents analyzed by the M-AP signal analysis unit 203. Note that the frame generation unit 202 may generate wireless frames without analysis by the M-AP signal analysis unit 203, for example, when operating as an M-AP or not cooperating with other APs. When the own device (AP103) operates as an S-AP, the M-AP signal analysis unit 203 interprets the contents of the wireless frame received from the M-AP and transmitted to the STA. For example, regarding a frame transmitted from AP 103 to STA 105, information such as how many APs other than AP 103 are transmitting frames to STA 105, and on which channel transmission and reception will be performed, is obtained by analysis here.

[0018] The UI control unit 204 includes hardware related to a user interface (UI) such as a touch panel or buttons for accepting operations on the AP 103 by a user (not shown) of the AP 103, and a program for controlling the hardware. The UI control unit 204 also has a function for presenting information to the user, such as displaying images or outputting audio. The storage unit 205 includes a storage device such as a ROM (Read Only Memory) or a RAM (Random Access Memory) for storing programs executed by the AP 103 and various data.

[0019] 3 shows a hardware configuration of the AP 103. As an example of the hardware configuration, the AP 103 has a storage unit 301, a control unit 302, a function unit 303, an input unit 304, an output unit 305, a communication unit 306, and antennas 307 to 308. The AP 104 and the STAs may also have a similar hardware configuration. The STAs have a general wireless LAN communication function, and therefore a description of the functional configuration thereof will be omitted.

[0020] The storage unit 301 is configured with both or either one of a ROM and a RAM, and stores various information such as programs for performing various operations described below and communication parameters for wireless communication. Note that, in addition to memories such as ROM and RAM, the storage unit 301 may be a storage medium such as a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, or a DVD.

[0021] The control unit 302 is configured with, for example, one or more processors such as a CPU or an MPU, an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), etc. Here, CPU is an acronym for Central Processing Unit, and MPU is an acronym for Micro Processing Unit. The control unit 302 controls the entire AP 103 by executing a program stored in the storage unit 301. Note that the control unit 302 may control the entire AP 103 in cooperation with the program stored in the storage unit 301 and an OS (Operating System).

[0022] Furthermore, the control unit 302 controls the functional unit 303 to execute predetermined processing such as imaging, printing, and projection. The functional unit 303 is hardware for the AP 103 to execute predetermined processing. For example, if the AP 103 is a camera, the functional unit 303 is an imaging unit and performs imaging processing. For example, if the AP 103 is a printer, the functional unit 303 is a printing unit and performs printing processing. For example, if the AP 103 is a projector, the functional unit 303 is a projection unit and performs projection processing. Data processed by the functional unit 303 may be data stored in the storage unit 301, or may be data communicated with other APs or STAs via a communication unit 306 described later.

[0023] The input unit 304 receives various operations from the user. The output unit 305 outputs various information to the user. Here, the output by the output unit 305 includes at least one of display on a screen, audio output by a speaker, vibration output, and the like. Note that both the input unit 304 and the output unit 305 may be realized by one module, such as a touch panel.

[0024] The communication unit 306 controls wireless communication conforming to the IEEE802.11 standard series and IP communication. The communication unit 306 is a so-called wireless chip, and may itself include one or more processors and memories. In this embodiment, the communication unit 306 can execute processing conforming to at least the IEEE802.11ax standard. The communication unit 306 controls the antennas 307 to 308 to transmit and receive wireless signals for wireless communication. The AP 103 communicates content such as image data, document data, and video data with other communication devices via the communication unit 306. The antennas 307 to 308 are, for example, antennas capable of transmitting and receiving at least one of the sub-GHz band, the 2.4 GHz band, the 5 GHz band, and the 6 GHz band. Note that there is no particular limit to the frequency bands (and combinations thereof) that can be supported by the antennas 307 to 308. Each of the antennas 307 to 308 may be a single antenna, or may be configured to include two or more antennas in order to perform MIMO (Multi-Input and Multi-Output) transmission and reception. 3, at least two antennas 307-308 are illustrated, but AP 103 may have only one antenna by using a multi-band antenna supporting two or more of the above-mentioned frequency bands, or AP 103 may have more antennas.

[0025] (Processing flow) Next, an example of the flow of the process executed by the AP103 and AP104 as described above and the flow of the process executed in the wireless communication network will be described. Figures 4 and 5 show an example of the flow of the process in which the AP103 is determined to operate as an S-AP, and after exchanging information with the AP102, the AP103 transmits data to the STA105 in cooperation with the AP104.

[0026] In this process, first, it is determined which AP among AP102 to AP104 will operate in the role of M-AP (and which AP will operate in the role of S-AP) (S401). For example, AP103 transmits parameters as an AP to AP102 (F501), and the parameters are compared to determine the AP that will operate as the M-AP. AP parameters can also be transmitted from AP104 to AP102 (not shown). In this process example, it is determined that AP102 will operate as an M-AP, and AP103 and AP104 will operate as S-APs. Thereafter, network information such as SSID and BSSID is notified from AP102 operating as an M-AP to AP103 and AP104 operating as S-APs. Then, AP103 and AP104 receive the notified network information (S402, F502). If the roles of the M-AP and the S-AP are determined in advance, the processes of S401, S402, F501, and F502 may be omitted.

[0027] The AP103 transmits a Beacon according to the notified information (F503). The Beacon includes information indicating that the multiple APs can transmit and receive data in cooperation with the connected STA. The AP here includes a logical AP, and one AP may include two logical APs, for example, an AP that operates in the 2.4 GHz band and an AP that operates in the 5 GHz band. That is, data transmission and reception by multiple APs may include data transmission and reception by one physical AP that can operate as multiple logical APs. The AP103, for example, adds a Multi-AP Information Element to the Beacon and transmits the Beacon including information such as the SSID, BSSID, and operating wireless channel used by multiple S-APs that can operate in cooperation. The method and configuration of storing this information are not limited to this, and the AP103 may store and transmit similar information in a similar format. When the STA105 receives the Beacon, it performs a connection process with at least one of the multiple S-APs based on the information included in the Beacon (S403, F504). The connection process here includes processes such as authentication and association defined in the IEEE802.11 standard series. When the AP 103 is in a connected state with the STA 105, the AP 103 notifies the M-AP that it is in a connected state with the STA together with the connection parameters (S404, F505). At this time, when one physical AP is in a connected state with each of the STAs as two logical APs, the M-AP may be notified of this. Note that in FIG. 5, only the AP 103 is in a connected state with the STA 105, but the AP 104 may also transmit a Beacon to connect with the STA 105 and notify the M-AP (AP 102) that it is in a connected state. However, this is not limited to this, and for example, the STA may be in a connected state with only one of a plurality of S-APs. In this case, for example, a wireless frame transmitted from another S-AP that is not in a connected state may be treated by the STA as a wireless frame from the S-AP that is in a connected state.In addition, even if the STA is connected to only one of the multiple S-APs, the STA may be able to recognize that the S-AP from which the wireless frame is sent is different from that from each S-AP. In this embodiment, the STA can recognize that signals are sent from multiple S-APs (that a Multi-AP Coordination system is configured) by decoding the preamble of the physical layer (PHY) of the wireless frame. That is, information indicating that a Multi-AP Coordination system is configured is included in the PHY preamble of the frame received by the S-AP from the M-AP or the frame received by the STA from the S-AP (or M-AP). This allows the device that receives the frame to confirm whether the AP that transmits data to the STA is multiple or single. This will be described later.

[0028] The M-AP manages the connection parameters of the S-AP that has become connected to the STA, and determines transmission parameters based on the information, and allocates subsequent transmission data (F506). Information on the transmission parameters determined in the M-AP is notified to the S-AP, and the AP103 determines its own transmission parameters based on the notified information (S405). The connection parameters may include information on the transmission rate and error rate of each connection. For example, the M-AP may allocate a large amount of transmission data to an S-AP having a connection with a high transmission rate, and allocate a small amount of transmission data to an S-AP having a connection with a low transmission rate. This allows data transmission from each S-AP to the STA to be performed efficiently. The connection parameters may be updated at regular intervals by each S-AP to reflect the current connection status, and notified to the M-AP. After that, when the S-AP receives transmission data from the M-AP to the STA (S406, F507), it transmits the data to the STA (S407, F508).

[0029] Such parallel transmission of data from multiple S-APs to one STA can be performed, for example, by transmitting a trigger frame from the M-AP to the S-AP to trigger transmission after the M-AP notifies the S-AP of the data to be transmitted. That is, when the S-AP has completed preparation of the data to be transmitted, the S-AP transmits the data to the STAs all at once based on receiving the trigger frame from the M-AP. When the data to be transmitted is transmitted from the M-AP to the S-AP, information instructing the transmission timing of the data may be notified to the S-AP together with the data to be transmitted. In this case, the multiple S-APs can transmit data to the STAs in parallel by transmitting the data to be transmitted at the indicated transmission timing.

[0030] On the other hand, when the S-AP receives data from the STA (S408), it transmits the received data to the M-AP (S409). Note that the order of data transmission and reception is merely an example, and data may be transmitted and received in a manner other than that shown in the figure, such as receiving data from the STA before transmitting data to the STA.

[0031] (Frame structure) Examples of PPDUs (Physical Layer (PHY) Protocol Data Units) defined in the IEEE802.11EHT standard and transmitted in S406-S407, F503, and F507-F508 are shown in Figs. 6-8. Fig. 6 shows an example of an EHT SU (Single User) PPDU, which is a PPDU for single user communication, and Fig. 7 shows an example of an EHT MU (Multi User) PPDU for multi-user communication. Fig. 8 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.

[0032] The PPDU includes the fields of a Short Training Field (STF), a Long Training Field (LTF), and a Signal Field (SIG). As shown in Fig. 6, the head of the PPDU includes L (Legacy)-STF 601, L-LTF 602, and L-SIG 603 for ensuring backward compatibility with the IEEE802.11a / b / g / n / ax standard. The frame formats in Figs. 7 and 8 also include L-STF (L-STF 701 and L-STF 801), L-LTF (L-LTF 702 and L-LTF 802), and L-SIG (L-SIG 703 and L-SIG 803). The L-LTF is placed immediately after the L-STF, and the L-SIG is placed immediately after the L-LTF. In addition, in the configurations of Figs. 6 to 8, RL-SIG (Repeated L-SIG, RL-SIG604, RL-SIG704, RL-SIG804) arranged immediately after the L-SIG is further included. In the RL-SIG field, the contents of the L-SIG are repeatedly transmitted. The RL-SIG enables the receiver to recognize that the PPDU is compliant with the IEEE802.11ax standard or later, and may be omitted in the IEEE802.11EHT in some cases. Also, instead of the RL-SIG, a field may be provided to enable the receiver to recognize that the PPDU is an IEEE802.11EHT PPDU. The fields of the PPDU do not necessarily need to be arranged in the order shown in Figs. 6 to 8, and may include new fields not shown in Figs. 6 to 8.

[0033] L-STF601 is used for detecting PHY frame signals, automatic gain control (AGC) and timing detection. L-LTF602 is used for high-precision frequency and time synchronization and for acquiring channel state information (CSI). L-SIG603 is used to transmit control information including data transmission rate and PHY frame length information. Legacy devices that comply with the IEEE802.11a / b / g / n / ax standards can decode the various legacy fields listed above.

[0034] Each PPDU further includes an EHT-SIG (EHT-SIG-A605, EHT-SIG-A705, EHT-SIG-B706, EHT-SIG-A805) for transmitting control information for EHT, which is placed immediately after the RL-SIG. Each PPDU also has an STF for EHT (EHT-STF606, 707, 806) and an LTF for EHT (EHT-LTF607, 708, 807). Each PPDU has a data field 608, 709, 808 and a packet extension field 609, 710, 809 after these control fields. The fields from the L-STF to the EHT-LTF of each PPDU are called a PHY preamble.

[0035] 6 to 8 show, as an example, a PPDU that can ensure backward compatibility, but when it is not necessary to ensure backward compatibility, for example, the legacy field may be omitted. In this case, for example, EHT-STF and EHT-LTF are used instead of L-STF and L-LTF to establish synchronization. In this case, the EHT-STF after the EHT-SIG field or one of the multiple EHT-LTFs may be omitted.

[0036] As shown in Tables 1 and 2 below, EHT-SIG-A605 and 805 included in EHT SU PPDU and EHT ER PPDU include EHT-SIG-A1 and EHT-SIG-A2 required for receiving PPDU. In this embodiment, a "Multi-AP" subfield indicating whether data is transmitted from multiple APs to the STA is included in EHT-SIG-A1. Also, EHT-SIG-A705 of EHT MU PPDU in FIG. 7 includes EHT-SIG-A1 and EHT-SIG-A2 required for receiving PPDU, as shown in Tables 3 and 4 below. In this embodiment, a "Multi-AP" subfield indicating whether data is transmitted from multiple APs to the STA is included in EHT-SIG-A2. Then, for example, when data is transmitted from multiple APs to the STA, 1 is stored in this "Multi-AP" subfield, and when data is transmitted from a single AP to the STA, 0 is stored in this field. The configurations of Tables 1 to 4 are merely examples, and for example, in the EHT SU PPDU and EHT ER PPDU, the Multi-AP information may be notified at a position other than the 15th bit of the EHT-SIG-A1 field. Similarly, in the EHT MU PPDU, the Multi-AP information may be notified at a position other than the 8th bit of the EHT-SIG-A2 field. In addition, the Multi-AP information may specify whether data is transmitted from multiple physical APs to the STA, or may specify whether data is transmitted from multiple logical APs to the STA. For example, even if data is transmitted physically from one AP to the STA, the Multi-AP subfield may be specified as 1 when data is transmitted logically from multiple APs to the STA.

[0037] [Table 1]

[0038] [Table 2]

[0039] [Table 3]

[0040] [Table 4]

[0041] Incidentally, EHT-SIG-B706 of the EHT MU PPDU includes information of the Common field as shown in Table 5 and the User Block field as shown in Table 6, which are necessary for receiving the PPDU.

[0042] [Table 5]

[0043] [Table 6]

[0044] As shown in Figure 6, the User Block field includes a User field, and information for each user is stored. The format of the User field differs depending on whether data is transmitted to multiple users by OFDMA or by MU-MIMO. Table 7 shows the User field when data is transmitted by OFDMA, and Table 8 shows the User field when data is transmitted by MU-MIMO.

[0045] [Table 7]

[0046] [Table 8]

[0047] The contents of these subfields are similar to those specified in the IEEE 802.11ax standard, so the explanation will be omitted here.

[0048] As described above, in the frame structure of the PPDU (EHT SU PPDU, EHT ER PPDU, and EHT MU PPDU) used in the IEEE802.11EHT standard, it is possible to inform the STA whether the AP that transmits data is single or multiple. That is, the S-AP can notify the STA whether there is an AP that transmits data in parallel to the common counterpart device (STA) other than the own device. Also, by transmitting this frame, the M-AP can notify the S-AP whether there is another S-AP that transmits data in parallel to the common counterpart device (STA) (or whether the M-AP transmits data in parallel). At this time, for example, when the STA executes a connection process with only one AP, the STA can recognize that there is another AP with which to communicate on a wireless channel different from the AP that performed the connection process, that is, on a wireless channel different from the wireless channel on which the own device is operating. The wireless channel here may include, for example, a frequency channel and a spatial channel. The STA can operate to identify multiple APs that are the source of data transmission, based on, for example, confirming that data from multiple APs is received by confirming the PHY preamble. The STA may, for example, confirm the sender address in the MAC (Medium Access Control) header for each of the multiple data streams to obtain information on the multiple APs. Furthermore, when the STA confirms information on the multiple APs, it may transmit acknowledgements (ACK / NACK) to the APs individually. Furthermore, when the wireless quality of data from a part of the APs is degraded, the STA may notify one of the APs (e.g., M-AP) that the AP is to be excluded from the target of Multi-AP Coordination. This enables the STA to maintain communication with high wireless quality. Furthermore, the STA or the AP may notify the user via the UI of information indicating whether data is being transmitted from multiple APs to the STA. Furthermore, when the STA does not support Multi-AP Coordination, when the STA receives a PPDU indicating that data is being transmitted from multiple APs, the STA may immediately discard the PPDU.This prevents the STA from unnecessarily decoding information after the Multi-AP subfield for a PPDU that the STA does not support, thereby reducing power consumption. Note that the present invention can also be implemented by an information processing device (e.g., a wireless chip) that generates the PHY preamble described above, in addition to the APs 102-104 and the STAs 105-107 that are communication devices.

[0049] In the above example, the Multi-AP subfield is prepared as a 1-bit field to indicate whether data is transmitted from multiple APs to the STA, but this is not limited to the above. For example, the Multi-AP subfield may be prepared as a 2-bit or more field to indicate the number of APs transmitting data to the STA. For example, when a 2-bit field is prepared, it can indicate that data is transmitted to the STA from one AP by "00", from two APs by "01", from three APs by "10", and from four or more APs by "11". Similarly, a 3-bit or more field can be prepared to indicate a larger number of APs.

[0050] <<Other embodiments>> The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0051] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0052] 102: AP (M-AP), 103, 104: AP (S-AP), 105 to 107: STA, 201, 206: wireless LAN control unit, 202: frame generation unit, 203: M-AP signal analysis unit, 204: UI control unit, 205: storage unit

Claims

1. A communication device conforming to the IEEE 802.11 standard series, A transmitting means for transmitting a radio frame having a physical layer (PHY) preamble and a data field, The preamble includes an L-STF (Legacy Short Training Field), an L-LTF (Legacy Long Training Field), an L-SIG (Legacy Signal Field), and a Signal Field arranged at least behind the L-SIG, The Signal Field includes a field including information indicating that the communication device and another communication device different from the communication device transmit data in cooperation with each other. A communication device comprising:

2. A communication device conforming to the IEEE 802.11 standard series, a receiving means for receiving a radio frame having a physical layer (PHY) preamble and a data field; The preamble includes an L-STF (Legacy Short Training Field), an L-LTF (Legacy Long Training Field), an L-SIG (Legacy Signal Field), and a Signal Field arranged at least behind the L-SIG, the Signal Field includes a field including information indicating that a first other communication device that has transmitted the wireless frame and a second other communication device different from the first other communication device transmit data in cooperation with each other; A communication device comprising:

3. 3. The communication device according to claim 1, wherein the field is a 1-bit field indicating whether the number of devices that transmit data in a coordinated manner is a single number or a plurality of devices.

4. 3. The communication device according to claim 1, wherein the field is a field of 2 or more bits indicating the number of devices that transmit data in a coordinated manner.

5. 5. The communication device according to claim 1, wherein the field includes information corresponding to the number of physical devices that transmit data.

6. 5. The communication device according to claim 1, wherein the field includes information corresponding to the number of logical devices that transmit data.

7. 3. The communication device of claim 2, configured to inform a user of information indicating whether data is received from a plurality of other devices based on the information in the field.

8. 3. The communications device of claim 2, further comprising: a first communication unit configured to receive data from a first plurality of other devices, the first plurality of other devices being configured to receive data from the first plurality of other devices, the first plurality of other devices being configured to receive data from the first plurality of other devices, the second plurality of other devices being configured to receive data from the first plurality of other devices, the first plurality of other devices being configured to receive data from the first plurality of other devices, the second plurality of other devices being configured to receive data from the first plurality of other devices, the third plurality of other devices being configured to receive data from the first plurality of other devices, the second plurality of other devices being configured to receive data from the first plurality of other devices, the third plurality of other devices being configured to receive data from the first plurality of other devices, the third plurality of other devices being configured to receive data from the first plurality of other devices, the fourth plurality of other devices being configured to receive data from the first plurality of other devices, the fourth plurality of other devices being configured to receive data from the first plurality of other devices, the fifth ...

9. The communication device according to claim 8, characterized in that the communication device is configured to obtain information about the plurality of other devices by checking a sender address in a MAC header of each piece of data received from the plurality of other devices, and when the information about the plurality of other devices is checked, to transmit an acknowledgement response to each piece of data received from the plurality of other devices.

10. The communication device according to claim 2, characterized in that, when wireless quality from some of the other devices is degraded, the communication device is configured to notify any of the other devices to exclude the some of the other devices from the other devices that transmit data in a coordinated manner.

11. The communication device according to claim 1 , wherein the communication device is a camera device.

12. The communication device according to claim 1 , wherein the communication device is a printer device.

13. The communication device according to claim 1 , further comprising a projection unit for performing a projection process.

14. 2. The communication device according to claim 1, wherein the communication device is a slave access point, and the communication device generates the wireless frame transmitted by the transmitting means based on data received from a master access point.

15. 15. The communication device according to claim 14, wherein the data received from the master access point includes information indicating whether there is a communication device transmitting data in parallel to a common partner device.

16. 16. The communication device according to claim 1, wherein the preamble includes information indicating that a Multi-AP Coordination system is configured.

17. 2. The communication device according to claim 1, wherein the transmission means transmits a beacon including information indicating that a plurality of communication devices are capable of cooperatively transmitting and receiving data to a common partner device.

18. 3. The communication device according to claim 2, wherein the receiving means receives a beacon including information indicating that a plurality of other devices are capable of coordinating data transmission and reception with respect to the communication device.

19. 2. The communication device according to claim 1, further comprising a generating unit for generating the radio frame.

20. A method for controlling a communication device conforming to the IEEE 802.11 series of standards, comprising: A transmitting step of transmitting a radio frame having a physical layer (PHY) preamble and a data field, The preamble includes an L-STF (Legacy Short Training Field), an L-LTF (Legacy Long Training Field), an L-SIG (Legacy Signal Field), and a Signal Field arranged at least behind the L-SIG, The Signal Field includes a field including information indicating that the communication device and another communication device different from the communication device transmit data in cooperation with each other. A control method comprising:

21. A method for controlling a communication device conforming to the IEEE 802.11 series of standards, comprising: A receiving step of receiving a radio frame having a physical layer (PHY) preamble and a data field, The preamble includes an L-STF (Legacy Short Training Field), an L-LTF (Legacy Long Training Field), an L-SIG (Legacy Signal Field), and a Signal Field arranged at least behind the L-SIG, the Signal Field includes a field including information indicating that a first other communication device that has transmitted the wireless frame and a second other communication device different from the first other communication device transmit data in cooperation with each other; A control method comprising:

22. For communication devices that comply with the IEEE 802.11 standard series, A program for executing a transmission step of transmitting a wireless frame having a physical layer (PHY) preamble and a data field, The preamble includes an L-STF (Legacy Short Training Field), an L-LTF (Legacy Long Training Field), an L-SIG (Legacy Signal Field), and a Signal Field arranged at least behind the L-SIG, The Signal Field includes a field including information indicating that the communication device and another communication device different from the communication device transmit data in cooperation with each other. A program characterized by:

23. For communication devices that comply with the IEEE 802.11 standard series, A program for executing a receiving step of receiving a radio frame having a physical layer (PHY) preamble and a data field, The preamble includes an L-STF (Legacy Short Training Field), an L-LTF (Legacy Long Training Field), an L-SIG (Legacy Signal Field), and a Signal Field arranged at least behind the L-SIG, the Signal Field includes a field including information indicating that a first other communication device that has transmitted the wireless frame and a second other communication device different from the first other communication device transmit data in cooperation with each other; A program characterized by:

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