COMMUNICATION DEVICE, COMMUNICATION METHOD, AND PROGRAM

Abstract

To properly configure settings for a plurality of access points to send data to a terminal in parallel.SOLUTION: In a communication device that transmits a radio frame having a physical layer (PHY) preamble and a data field, the preamble contains a field to set the first Basic Service Set (BSS) color, and the first BSS color field is set to a value depending on whether the communication device and the first other communication device cooperate to transmit a wireless frame to the second other communication device.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] The Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard is known as a communication standard for wireless local area networks (wireless LANs). The IEEE 802.11ax standard, which is the latest standard in the IEEE 802.11 series, uses orthogonal frequency division multiple access (OFDMA) to achieve high peak throughput as well as improved communication speeds under congested conditions (see Patent Document 1).

[0003] Currently, 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 EHT, a Multi-AP Coordination configuration is being considered in order to achieve improved throughput, in which multiple spatially distributed access points (APs) cooperate to transmit data to a single STA (Station). [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] The IEEE802.11ax 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 BSS color of the AP to which the device is connected, the communication device treats the wireless frame as an Intra-BSS frame. On the other hand, in the IEEE802.11EHT, the use of a Multi-AP Coordination configuration as described above is being considered, but it is not clear how the BSS color should be set in this case.

[0006] The present invention provides a method for appropriately executing settings for multiple access points to transmit data in parallel to a terminal. [Means for solving the problem]

[0007] According to one aspect of the present invention Access Points teeth, A control means for coordinating with other access points, based on the coordinating operation, It has a preamble and a data field. Rufu A means for transmitting frames and, have Access Points And, The transmitting means is In the preamble In the above, the other access point is set Basic Service Set (BSS) color Information identical to that pertaining to of include before Notes Send a frame do. Effect of the Invention

[0008] According to the present invention, it is possible to appropriately execute settings for a plurality of access points to transmit data to a terminal in parallel. [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 the hardware configuration of an AP and a STA. [Diagram 3] FIG. 2 is a diagram illustrating an example of the functional configuration of an AP and a STA. [Figure 4] A figure showing an example of a PHY frame structure of an EHT SU PPDU. [Diagram 5] A diagram showing an example of a PHY frame structure of an EHT ER PPDU. [Figure 6] FIG. 2 is a diagram illustrating an example of a PHY frame structure of an EHT MU PPDU. [Figure 7] FIG. 1 is a diagram illustrating an example of a flow of processing executed in a network. [Figure 8] FIG. 11 is a diagram illustrating an example of a flow of processing executed in an AP. 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, AP104) and terminals (STA103, STA105), each of which is an IEEE802.11EHT (Extremely High Throughput) device. In the following, when a specific device is not specified, the access point may be called an "AP" and the station may be called an "STA" without a reference number. Note that FIG. 1 shows a wireless communication network including two APs and two STAs as an example, but the number of these communication devices may be, for example, three or more. In FIG. 1, the communication range of the network formed by the AP102 and AP104 is shown by a circle 101. Note that this communication range may cover a wider range or may cover only a narrower range. Also, in FIG. 1, an STA conforming to the IEEE802.11EHT standard is shown, but an STA supporting only a standard (legacy standard) of a generation earlier than the IEEE802.11EHT standard may exist. EHT may also be interpreted as an abbreviation for Extreme High Throughput.

[0012] In this example, the AP 102 and the AP 104 are assumed to be capable of receiving signals transmitted by each other AP. The connection form is not particularly limited, and the AP 102 and the AP 104 may be connected by wire or wirelessly. The AP 102 and the AP 104 support the Multi-AP Coordination configuration of IEEE802.11EHT and are assumed to be capable of transmitting data to one STA in parallel in cooperation with each other. For example, the STA 105 can transmit and receive wireless frames in parallel with the AP 102 and the AP 104 that operate in cooperation with each other. The STA 105 may be configured to have, for example, multiple wireless LAN control units and to transmit and receive wireless frames with multiple APs using different wireless channels. The STA 105 may have one physical control unit capable of processing multiple frames received in parallel via multiple wireless channels. That is, the STA 105 has a configuration that can logically process multiple wireless communications in parallel using one or more physical control units.

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

[0014] The storage unit 201 is configured with a ROM and / or 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 201 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.

[0015] The control unit 202 is configured with, 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 an acronym for Central Processing Unit, and MPU is an acronym for Micro Processing Unit. The control unit 202 controls the entire device by executing a program stored in the storage unit 201. Note that the control unit 202 may control the entire device in cooperation with the program stored in the storage unit 201 and an OS (Operating System).

[0016] Furthermore, the control unit 202 controls the functional unit 203 to execute predetermined processes such as imaging, printing, and projection. The functional unit 203 is hardware for the device to execute predetermined processes. For example, if the device is a camera, the functional unit 203 is an imaging unit and executes imaging processing. For example, if the device is a printer, the functional unit 203 is a printing unit and executes printing processing. For example, if the device is a projector, the functional unit 203 is a projection unit and executes projection processing. 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 outputs various types of information to the user. Here, the output by the output unit 205 includes at least one of, for example, display on a screen, audio output by a speaker, vibration output, and the like. Note that both the input unit 204 and the output unit 205 may be realized by one module, such as a touch panel.

[0018] The communication unit 206 controls wireless communication conforming to the IEEE802.11 standard series and IP communication. In this embodiment, the communication unit 206 can execute processing conforming to at least the IEEE802.11EHT 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 an antenna 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 limitation on the frequency bands (and their combinations) that can be supported by the antenna 207. The antenna 207 may be a single antenna, or may be a set of two or more antennas for performing MIMO (Multi-Input and Multi-Output) transmission and reception. Also, although one antenna 207 is shown in FIG. 2, the device may include, for example, two or more antennas (two or more sets) that can support different frequency bands. The antenna 207 is configured to be compatible with communication of Distributed Coordination of the IEEE 802.11 EHT standard. For example, the AP has a configuration that enables transmission of Distributed MIMO (D-MIMO) for Joint Transmission (JTX).

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

[0020] 3 shows an example of the functional configuration of an AP (AP 102, AP 104). The AP includes, for example, 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 transmitting and receiving wireless signals to and from other wireless LAN devices (e.g., other APs and STAs) and programs for controlling them. The wireless LAN control unit 301 executes 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 IEEE802.11 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, for example, wireless frames including data to be transmitted to the STA by the other AP, and trigger frames (JTX TF) that instruct the timing at which the wireless frames including the 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 local device (AP 102 or AP 104) establishes a BSS (Basic Service Set), the BSS color setting unit 303 sets the BSS color used in the BSS. The BSS color setting unit 303 sets the value of the BSS color for the wireless frame to be transmitted to the STA connected to the local device. On the other hand, when the BSS color setting unit 303 transmits data by JTX to a STA connected to another AP, it sets the BSS color used in the BSS established by the other AP for the wireless frame to be transmitted to the STA. That is, when the BSS color setting unit 303 transmits a wireless frame by JTX to a STA connected to another AP different from the local device, it uses the BSS color of the other AP, not the BSS color used in the BSS established by the local device. This allows multiple wireless frames received by the STA to be wireless frames set with the BSS color used in the BSS to which the STA is connected. Therefore, the STA can handle all wireless frames received from multiple APs as Intra-BSS frames. On the other hand, the BSS color setting unit 303 sets the BSS color of the BSS established by the STA for wireless frames other than JTX, so that the STA connected to another AP can handle the wireless frame as an Inter-BSS frame. The STA can execute different control 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 when the reception power of the wireless frame does not exceed a predetermined value, but the predetermined value for the Inter-BSS frame can be set to a value higher than the predetermined value for the Intra-BSS frame. According to this, even if a wireless frame is received with power exceeding the predetermined value for the Intra-BSS frame, if the wireless frame is an Inter-BSS wireless frame, the STA may be able to obtain a transmission opportunity.Therefore, by having an AP use a BSS color different from other APs except during JTX, it is possible to increase communication opportunities for STAs connected to other APs, thereby improving the frequency utilization efficiency of the entire system.

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

[0024] The STA has the functions of a general STA, but may also have the function of receiving wireless frames transmitted in a Multi-AP Coordination configuration.

[0025] (Frame structure) An example of the structure of a PPDU (Physical layer (PHY) Protocol Data Unit) conforming to the IEEE802.11 EHT standard will be described with reference to Figs. 4 to 6. Fig. 4 shows an example of an EHT SU (Single User) PPDU, which is a PPDU for single user communication, and Fig. 5 shows an example of an EHT MU (Multi User) PPDU for multi-user communication. Fig. 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 need to be arranged in the order shown in Figs. 4 to 6, and may include new fields not shown in Figs. 4 to 6.

[0026] 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. 4, the head of the PPDU includes an L (Legacy)-STF 401, an L-LTF 402, and an L-SIG 403 for ensuring backward compatibility with the IEEE802.11a / b / g / n / ax standard. The frame formats in Figs. 5 and 6 also include an L-STF (L-STF 501 and L-STF 601), an L-LTF (L-LTF 502 and L-LTF 602), and an L-SIG (L-SIG 503 and L-SIG 603). The L-LTF is placed immediately after the L-STF, and the L-SIG is placed immediately after the L-LTF. In addition, the configurations of Figs. 4 to 6 further include an RL-SIG (Repeated L-SIG, RL-SIG404, RL-SIG504, RL-SIG604) arranged immediately after the L-SIG. 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.

[0027] L-STF401 is used for detecting physical layer (PHY) frame signals, automatic gain control (AGC) and timing detection. L-LTF402 is used for highly accurate frequency and time synchronization and for acquiring propagation channel information (CSI). L-SIG403 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.

[0028] Each PPDU further includes an EHT-SIG (EHT-SIG-A 405, EHT-SIG-A 505, EHT-SIG-B 506, EHT-SIG-A 605) for transmitting control information for EHT, which is placed immediately after the RL-SIG. Each PPDU also has an STF for EHT (EHT-STF 406, 507, 606) and an LTF for EHT (EHT-LTF 407, 508, 607). Each PPDU has a data field 408, 509, 608 and a packet extension field 409, 710, 609 after these control fields. The fields from the L-STF to the EHT-LTF of each PPDU are called a PHY preamble.

[0029] 4 to 6 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.

[0030] As shown in Tables 1 and 2 below, EHT-SIG-A405 and 605 included in EHT SU PPDU and EHT ER PPDU include EHT-SIG-A1 and EHT-SIG-A2 necessary for PPDU reception. EHT-SIG-A1 includes a 6-bit "BSS color" subfield. Also, EHT-SIG-A505 of EHT MU PPDU in FIG. 5 includes EHT-SIG-A1 and EHT-SIG-A2 necessary for PPDU reception, as shown in Tables 3 and 4 below. Also, in this PPDU, EHT-SIG-A1 includes a 6-bit "BSS color" subfield. Note that the configurations of Tables 1 to 4 are merely examples, and information other than the information shown in these tables may be included in the EHT-SIG field, or part of the information shown in these tables may be removed from the EHT-SIG field.

[0031] [Table 1]

[0032] [Table 2]

[0033] [Table 3]

[0034] [Table 4]

[0035] (Processing flow) Next, an example of the flow of processing executed by the above-mentioned AP and the flow of processing executed in the wireless communication network will be described with reference to Fig. 7 and Fig. 8. Fig. 7 shows an example of the flow of processing in the wireless communication network, and Fig. 8 shows an example of the flow of processing executed by the AP 102 and the AP 104.

[0036] First, the AP 102 establishes a first BSS (BSS1) (F701, S801). In this embodiment, it is assumed that a setting is made to use BSS color1 in BSS1. The AP 104 establishes a second BSS (BSS2) (F702, S801). Here, in this embodiment, it is assumed that a setting is made to use BSS color2, which is different from BSS color1, in BSS2. Each AP broadcasts an IEEE802.11 Beacon at regular intervals and accepts a connection request from a STA, thereby mediating communication between the STA and another STA, or between the STA and a Distribution System (DS).

[0037] The AP 102 executes a connection procedure with the STA 103 and transitions to a connected state (F703). Similarly, the AP 104 executes a connection procedure with the STA 105 and transitions to a connected state (F704). In this connection procedure, the AP notifies the STA of operation status information, as in the case of IEEE802.11ax. This operation status information includes a BSS color value. As described above, the BSS color is 6-bit information that identifies the BSS included in the preamble of the physical layer (PHY). The BSS color value allows the STA to know whether the received wireless frame is a frame of the BSS to which the STA belongs (intra-BSS) or a frame of the BSS to which the STA does not belong (inter-BSS).

[0038] The AP 102 may transmit a wireless frame to the STA 103 (F705). This wireless frame is a PPDU shown in any one of Figs. 4 to 6, and a value indicating the BSS color 1 used in BSS 1 is stored in the BSS color subfield. Similarly, the AP 104 may transmit a wireless frame to the STA 105 (F706). This wireless frame is also a PPDU shown in any one of Figs. 4 to 6, and a value indicating the BSS color 2 used in BSS 2 is stored in the BSS color subfield. As shown in the above table, the BSS color subfield is the 9th to 14th bits (B8 to B13) of the EHT-SIG-A1 in the case of an EHT SU PPDU or an EHT ER PPDU. Also, the BSS color subfield is the 6th to 11th bits (B5 to B10) of the EHT-SIG-A1 in the case of an EHT MU PPDU.

[0039] Thereafter, it is assumed that AP102 and AP104 have decided to cooperate to perform data transmission to a common STA in parallel. For example, when AP104 detects that there is a large amount of data to be transmitted to STA105, it may decide to cooperate with AP102, which is another AP present in the vicinity, to transmit data to STA105 in parallel. Also, AP102 or AP104 may decide to make preparations for cooperative transmission with other APs even when there is no planned large-capacity data communication to a specific STA, in case large-capacity data communication occurs in the future. When it is decided that cooperative transmission by a plurality of APs will be performed or preparations therefor will be made, AP102 and AP104 perform negotiation for JTX (Joint Transmission) (F707, S802). Note that hereinafter, the negotiation for JTX may sometimes be simply referred to as "negotiation". In the negotiation, the AP that executes the negotiation can determine whether it will operate in the role of either M-AP or S-AP. Here, it is assumed that it has been decided that AP102 will operate as M-AP (YES in F708, S803), and it has been decided that AP104 will operate as S-AP (NO in F709, S803). Also, in this negotiation, it may be determined which STA is the target of JTX and which AP will associate with it.

[0040] After the negotiation is completed, the AP104, which is the S-AP, notifies the AP102, which is the M-AP, of the information of the STA105 connected to the own device and the information of the BSS color2 used in the BSS2 established by the own device (F710, S804, S811). Here, the information of the STA may include information of the MAC (medium access control) address of the STA. Note that this information may be exchanged between the APs at the time of negotiation, or may be notified from the S-AP to the M-AP at other timing. In addition, the AP102 may notify the AP104 of the information of the STA103 connected to the own device and the information of the BSS color1 used in the BSS1 established by the own device. Furthermore, when the AP102 and the AP104 perform JTX to transmit data to a specific STA, the AP connected to the STA may notify the other AP of the information of the STA and the BSS color. However, since the M-AP can specify the STA and BSS color to which data is to be transmitted when transmitting data to be transmitted or in a JTX trigger frame, as described below, the M-AP does not need to provide information to the S-AP at this point.

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

[0042] When the data to be transmitted is transmitted from the M-AP to the S-AP, the information on the BSS color to be used may be notified from the M-AP to the S-AP. In this embodiment, since data is transmitted to the STA105 by JTX, the BSS color 2 used by the AP104 to which the STA105 is connected may be notified as the information on the BSS color to be used. If the BSS color to be used matches the BSS color used in the S-AP, or if the BSS color to be used in JTX is known in advance, the M-AP does not need to notify the S-AP of the BSS color information. In other words, when the M-AP transmits data to the STA connected to the S-AP by JTX, or when the BSS color information has been exchanged with the STA to which the data is to be transmitted by JTX, the M-AP does not need to notify the S-AP of the BSS color information. For example, when data is transmitted to the STA103 by JTX, the AP102 may notify the AP104 of the BSS color to be used as the information on the BSS color to be used. When data is transmitted using the above-mentioned PPDU, the PPDU contains a PHY preamble that notifies the BSS color, so 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 BSS color used by the device itself, but since it is operating in JTX mode, it does not discard the data in the wireless frame.

[0043] After transmitting and receiving the data to be transmitted, the AP102 transmits a JTX trigger frame (TF) to the AP104 to transmit a wireless frame including the data to be transmitted (F713, S808, S814). The AP102 can use the JTX TF to instruct the AP104 to transmit a wireless frame to the STA105 and specify the timing of the transmission. Then, the AP102 and the AP104 transmit data to the STA105 in parallel (F714, F715, S810) at a timing specified by the JTX TF (YES in S809). The transmission timing can be a predetermined time (SIFS, Short Inter Frame Space) after the transmission and reception of the JTX TF. In this case, the transmission timing is specified by the transmission and reception of the JTX TF itself. In this case, the JTX TF can be transmitted at a timing corresponding to the timing at which the AP102 and the AP104 should transmit a wireless frame to the STA105. Also, information specifying the transmission timing may be included in the JTX TF frame. In this case, the AP102 and the AP104 may determine when to transmit the wireless frame using the specified transmission timing and a timer, clock, or the like in their own devices. In this way, the AP102 and the AP104 can transmit wireless frames in synchronization using the JTX TF.

[0044] In this data transmission, the BSS color used in the BSS to which the STA to which the data is to be transmitted belongs (the AP to which the STA is connected) is set in the PHY preamble in the wireless frame. In the example of FIG. 7, the BSS color 2 used in the BSS 2 to which the STA 105 to which the data is to be transmitted belongs is set in the wireless frame. That is, the AP 104 transmits wireless frames using the BSS color 2 used in the own device as is, but the AP 102 transmits wireless frames using the BSS color 2 different from the BSS color 1 used in the own device. However, the BSS color of the BSS 1 established by the AP 102 is not changed from the BSS color 1. That is, the AP 102 does not change the BSS color of the BSS established by the own device, but when transmitting data in JTX, the BSS color used in the BSS to which the STA to which the data is to be transmitted belongs is set in the wireless frame and transmitted. At this time, even if the AP 102 is operating in the JTX mode, the AP 102 may transmit data to the STA (STA 103) connected to the own device. In this case, AP102 may set the BSS color 1 used in BSS1 established by itself in the wireless frame and transmit data. That is, while operating in JTX mode, AP102 sets the BSS color of the BSS to which the STA belongs in the wireless frame and transmits it. The same is true for AP104. That is, AP104 uses BSS color 2 in BSS2 established by itself, but when instructed by AP102 to transmit data to STA103 in JTX, for example, it may transmit a wireless frame with BSS color 1 set to STA103. At this time, AP104 does not change the BSS color of BSS2.

[0045] In this way, each AP does not change the BSS color of the BSS it established, and therefore does not instruct the connected STA to change the BSS color. This prevents unnecessary changes to the STA settings, and can, for example, suppress increases in STA power consumption. 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 the wireless frame during JTX without changing the BSS color setting.

[0046] 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.

[0047] 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]

[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: storage unit

Claims

1. An access point, A control means for coordinating with other access points; a transmitting means for wirelessly transmitting a frame having a preamble and a data field based on the cooperative operation, The transmitting means transmits the frame including, in the preamble, information identical to information related to a Basic Service Set (BSS) color set in the other access point. An access point characterized by:

2. The transmitting means transmits the frame including information identical to information related to the BSS color set in the other access point when the communication device to which the frame is to be transmitted belongs to a BSS established by the other access point.

2. The access point according to claim 1 .

3. The access point acquires, from the other access point, information related to the BSS color set in the other access point.

3. The access point according to claim 2 .

4. the access point acquires, from the other access point, information on a communication device to which the frame is to be transmitted; 3. The access point according to claim 2 .

5. A communication method in an access point, comprising: a control step for coordinating with other access points; a transmitting step of wirelessly transmitting a frame having a preamble and a data field based on the cooperative operation, transmitting the frame including, in the preamble, information identical to information related to a Basic Service Set (BSS) color set in the other access point; A communication method comprising:

6. A program for causing a computer to operate as each of the means included in the access point according to any one of claims 1 to 4.

Images