Access point device, radio communication device, and radio communication system

Abstract

To prevent a reduction in frequency utilization efficiency, while avoiding interference due to execution of transmission using the same resource between adjacent BSSs, when Joint Transmission and BSS Coloring are used together, which are transmitted in cooperation by adjacent APs.SOLUTION: In executing JT, each AP notifies information on two BSS Colors, the BSS Color of a BSS to which the AP originally belongs and a special BSS Color, within the BSS by using a beacon frame, and in executing the actual JT and in executing individual transmission in each BSS, the AP adds information on at least one or more different BSS Colors before executing the transmission.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an access point device, a wireless communication device, and a wireless communication system. [Background technology]

[0002] The Institute of Electrical and Electronics Engineers Inc. (IEEE) is continually working on updating the specifications of IEEE 802.11, the wireless LAN standard, in order to achieve faster wireless LAN (Local Area Network) communications and more efficient frequency utilization. Wireless LANs enable wireless communications using frequency bands (unlicensed bands) that can be used without permission (license) from countries or regions. For personal use, such as at home, the IEEE 802.11 bands are used to connect to WAN (Wide Area Network) lines to the Internet, etc. The line termination device includes a wireless LAN access point function, or the wireless LAN AP ( By connecting a wireless LAN access point (also called base station equipment) to a line termination device, internet access from within the home has become wireless. This has enabled wireless LAN STAs (also called terminal devices) such as smartphones and personal computers to be connected to the network. (called) can connect to a wireless LAN AP and access the Internet.

[0003] The IEEE 802.11ax standard was completed in 2021, and wireless LAN devices compliant with this standard, as well as communication devices such as smartphones and personal computers equipped with such wireless LAN devices, have appeared on the market as Wi-Fi 6 (a registered trademark, the name for IEEE 802.11ax-compliant products certified by the Wi-Fi Alliance). Currently, standardization activities for IEEE 802.11be, the successor to IEEE 802.11ax, are underway, and discussions are also underway for its successor, IEEE 802.11bn. With the rapid spread of wireless LAN devices, recent IEEE 802.11 standardization efforts have focused on high-efficiency communication in environments where wireless LAN devices are densely deployed.

[0004] BSS Coloring, introduced in IEEE 802.11ax, is a technology for improving frequency utilization efficiency in densely deployed environments of wireless LAN devices. In IEEE 802.11, the basic configuration of communication between an AP and one or more STAs is called a Basic Service Set (BSS), and the A within the BSS is The P and STAs each communicate based on CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance). In an environment where different BSSs are deployed adjacent to each other, if a BSS detects communication from an adjacent BSS, it will refrain from communicating even if it is capable of communicating using the same channel, resulting in reduced frequency utilization efficiency. In response to this issue, BSS Coloring assigns a different identifier, called a BSS Color, to each adjacent BSS to distinguish between communications between adjacent BSSs. This allows a BSS to ignore interference on the same channel and initiate communication on its own BSS. Furthermore, by controlling the transmission power during communication on the own BSS, it is possible to reduce the impact on adjacent BSSs communicating on the same channel. Thus, IEEE 802.11ax introduces a mechanism for achieving efficient communication even in a densely populated BSS environment.

[0005] In addition to improving communication efficiency, technology to improve communication quality for individual STAs is also being studied, and a technology called Joint Transmission (JT) is being considered in the IEEE 802.11bn standardization. JT is a technology in which APs of neighboring BSSs cooperate with each other to transmit the same data for a specific STA using the same resources, thereby improving the reception quality of STAs located in areas that overlap with neighboring BSSs. This makes it possible to:

[0006] However, when BSS Coloring and JT are used together, as mentioned above, different BSS Colors are set in adjacent BSSs, and these BSS Colors are added to data as headers before transmission, which causes a problem that when JT is applied, it is not possible to transmit identical frames between adjacent BSSs, and JT does not work effectively. To address this, several methods have been proposed in which APs in adjacent BSSs cooperate with each other to align BSS Colors when transmitting to STAs that are the targets of JT (Non-Patent Document 1).

[0007] Non-Patent Document 1 proposes the following two methods for setting and transmitting BSS Color when JT is applied. (A) A special BSS Color is set that is separate from the BSS Colors of the multiple BSSs that perform JT (Figure 1-A). (B) Using all BSS colors in multiple BSSs where JT is performed (Figure 1-B). (Common to (A) and (B)) In BSS1, which contains an AP (AP1) called the Coordinator AP that leads coordination between APs, AP1 sends information about the BSS Color set for JT in a management frame within BSS1. In BSS2, which contains an AP (AP2) called the Coordinated AP that performs JT in cooperation with the Coordinator AP, AP2 sends information about the BSS Color that was originally set in BSS2 in a management frame within BSS2. When sending data to the STA (STA1) that is the target of JT, both APs send frames with the BSS Color set as above (A) or (B) added to the data.

[0008] In the two methods described in Non-Patent Document 1, when data is sent to STA1, which is the target of JT, the BSS Color information attached to the data and sent from the two APs can be matched, and since STA1 already knows this BSS Color information from the management frame, it can receive and demodulate the data as if it were within the BSS to which it belongs. [Prior art documents] [Non-patent literature]

[0009] [Non-Patent Document 1] IEEE802.11-23 / 1841r0,Nov.2023 Summary of the Invention [Problem to be solved by the invention]

[0010] In the method (A) of Non-Patent Document 1 shown in Fig. 1, although a frame by JT intended for STA1 is a frame transmitted by AP2, STA2 may regard it as a frame of a different BSS, and STA2 may transmit using the same resource. In such a case, a problem occurs in which transmissions by JT and STA2 interfere with each other.

[0011] On the other hand, in (B), because the JT frame for STA1 also contains BSS Color 2 information, STA2 regards the frame as belonging to its own BSS and operates to refrain from transmitting using the same resources as the JT, thereby avoiding the problem of (A) above. However, because BSS1 broadcasts BSS Color 1+2 information in a management frame, even when individual data transmissions are performed in BSS2 that do not include JT but only BSS Color 2, transmissions using the same resources within BSS1 may be refrained from, resulting in a problem of reduced frequency utilization efficiency. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems, the access point device, wireless communication device, and wireless communication system according to the present invention are as follows.

[0013] (1) That is, a wireless access point device according to one aspect of the present invention sets a basic service zone (BSS) for wireless communication services with one or more wireless communication devices, and performs communication within the BSS. a wireless access point device that controls a management range different from the management range controlled by the wireless access point device itself to perform cooperative transmission in which the wireless communication device and another wireless access point device that controls a management range different from the management range controlled by the wireless access point device itself perform cooperative transmission in which the same signal addressed to the specific wireless communication device is transmitted using the same wireless resources; the wireless access point device includes a cooperative transmission control unit that determines whether to perform the cooperative transmission and controls notification of information necessary for the cooperative transmission; and an identifier control unit that controls identifier information for distinguishing the management range controlled by the wireless access point device itself from other management ranges; the identifier control unit controls the identifier information so that a management frame including information on two different identifiers for distinguishing the management range controlled by the wireless access point device itself from other management ranges is notified to the wireless communication device within the management range controlled by the wireless access point device itself; and the identifier control unit adds information on at least one of the different identifiers to a data frame in the cooperative transmission and a data frame when the cooperative transmission is not performed, and transmits the data frame.

[0014] (2) In addition, in a wireless access point device according to one embodiment of the present invention, the management frame is a frame that is transmitted periodically for each management range, and at least one data frame for the cooperative transmission and one data frame for when the cooperative transmission is not performed are transmitted within a time period within the period of the management frame.

[0015] (3) Furthermore, in a wireless access point device according to one embodiment of the present invention, the identifiers added to the data frame in the cooperative transmission and the data frame when the cooperative transmission is not performed are two identifiers each, and one of the identifiers is different between the data frame in the cooperative transmission and the data frame when the cooperative transmission is not performed.

[0016] (4) In a wireless access point device according to an aspect of the present invention, the different identifiers added to the data frame in the cooperative transmission and the data frame in the case where the cooperative transmission is not performed are each a single identifier.

[0017] (5) Furthermore, a wireless access point device according to an aspect of the present invention adds at least one of the identifiers to a control frame separate from the management frame and transmits the control frame.

[0018] (6) In addition, in a wireless access point device according to one aspect of the present invention, the control frame is a frame transmitted prior to the transmission of the data frame, and different identifiers are attached to the data frame in the cooperative transmission and the data frame in the case where the cooperative transmission is not performed, and the control frame is transmitted.

[0019] (7) Furthermore, a wireless communication device according to one aspect of the present invention is a wireless communication device that is capable of managing a wireless communication service (BSS). and controls communications in the management range, and receives the same signal transmitted by the same wireless resource in cooperation with the first wireless access point device and a second wireless access point device that controls a management range different from the first management range. The wireless communication device receives a management frame including information on two different identifiers for distinguishing the management range from other management ranges, and includes an identifier determination unit that selects one of the two different identifiers received, and transmits the data frame by adding information on the identifier selected by the identifier determination unit.

[0020] (8) Furthermore, a wireless communication device according to an aspect of the present invention adds information about the selected identifier to a control frame transmitted prior to transmitting the data frame.

[0021] (9) A wireless communication system according to an aspect of the present invention includes a wireless access point device that sets a management range (BSS) of a wireless communication service and controls communications within the management range; a wireless communication system that performs cooperative transmission in which two different wireless access point devices transmit the same signal addressed to a specific wireless communication device using the same wireless resource, and the wireless access point device notifies the wireless communication devices within the management range of a management frame including information on two different identifiers for distinguishing the management range from other management ranges, and adds information on at least one or more different identifiers to data frames in the cooperative transmission and data frames when the cooperative transmission is not performed, and transmits the data frames from the wireless access point device.

[0022] (10) In addition, in a wireless communication system according to one embodiment of the present invention, the management frame is a frame that is transmitted periodically for each management range, and at least one data frame for the cooperative transmission and one data frame for when the cooperative transmission is not performed are transmitted within a time period within the period of the management frame. [Effects of the Invention]

[0023] According to the wireless communication device and wireless communication method of the present invention, when BSS Coloring and JT are used in combination, it is possible to avoid interference caused by transmission using the same resources between adjacent BSSs while suppressing a decrease in frequency utilization efficiency. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 10 is a diagram showing an example of BSS Color settings when JT is applied to a wireless LAN system. [Figure 2] FIG. 1 is a diagram illustrating an example of a PPDU configuration related to a wireless LAN system. [Figure 3] 1 is a diagram illustrating an example of a configuration of a communication system according to an aspect of the present invention. [Figure 4] 1 is a diagram illustrating an example of frame transmission and reception in a communication system according to an aspect of the present invention. [Figure 5]1 is a block diagram showing an example of the configuration of an AP according to an embodiment of the present invention. [Figure 6] 1 is a block diagram showing an example of the configuration of an STA according to an embodiment of the present invention. [Figure 7] 1 is a diagram illustrating an example of frame transmission and reception in a communication system according to an aspect of the present invention. [Figure 8] 1 is a diagram illustrating an example of frame transmission and reception in a communication system according to an aspect of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] The wireless communication system in this embodiment targets technologies such as BSS Coloring introduced in IEEE 802.11ax and Joint Transmission (JT) being considered in IEEE 802.11bn, so the explanation will be given using IEEE 802.11be, which is closest to IEEE 802.11bn, as a basic example.

[0026] The wireless communication system in this embodiment includes an AP (Access Point, also called a base station device) and one or more STAs (Station, also called a terminal device). This is also called a Basic Service Set (BSS, management range), and the The AP and STA communicate based on CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance). It is possible to transmit multiple types of frames (communication frames) with the same format. The frames are transmitted through the physical layer (PHY), medium access control (MAC), and Access Control layer, Logical Link Control (LLC) layer, It is defined as follows:

[0027] A frame in the PHY layer is called a physical protocol data unit (PPDU), and an example of a PPDU in IEEE 802.11be is a PPDU as shown in FIG. 2. The L-STF, L-LTF, and L-SIG included in the format of FIG. 2 are reference signals and control signals for signal detection and synchronization, acquisition of channel information for data demodulation, and acquisition of control information for data demodulation, respectively. These are called legacy preambles and are preambles used in IEEE 802.11-compliant devices prior to IEEE 802.11be. The RL-SIG is also a preamble used in IEEE 802.11ax, and the U-SIG and subsequent preambles are preambles and data used for IEEE 802.11be. In this embodiment, identifier information for distinguishing a BSS (management range) from other BSSs is called a BSS Color, and information indicating the BSS Color of interest in this embodiment is specifically included in the U-SIG in the format configuration shown in FIG. 2. In addition, the legacy preamble, RL-SIG, U-SIG, and the signals up to the subsequent STF and LTF are collectively called the PHY header.

[0028] The MAC layer frame is called a MAC Protocol Data Unit (MPDU), and consists of a MAC header containing information for signal processing at the MAC layer, a MAC Service Data Unit (MSDU) or frame body, which is the data unit processed at the MAC layer, and a MAC Protocol Data Unit (MPDU). It also consists of a frame check section (FCS: Frame Check Sequence) that checks whether there are any errors in the frame.

[0029] Frame types in the MAC layer are broadly classified into three types: management frames that manage the connection status between devices, control frames that manage the communication status between devices, and data frames that contain the actual transmitted data. Each of these is further classified into multiple subframe types. Management frames include beacon frames, probe request frames, probe response frames, authentication frames, association request frames, and association response frames. Control frames include acknowledgement (Ack or ACK) frames, block acknowledgement (BA or Block These include Ack (Block Acknowledgement) frames, RTS (Request To Send) frames, CTS (Clear To Send) frames, and Trigger frames. BlockAck can acknowledge multiple MPDUs (notify completion of reception). Data frames include Data frames and CF-poll frames. Each device can recognize the frame type and subframe type of a received frame by reading the contents of the frame control field included in the MAC header.

[0030] A beacon frame, which is one of the management frames, includes a field indicating the period (beacon interval) at which beacons are transmitted and an SSID. APs periodically broadcast beacon frames within a BSS, and STAs can recognize nearby APs by receiving the beacon frames. The HE Operation section of a beacon frame also includes information about the BSS Color, and by receiving the beacon frames periodically broadcast by the AP, the STA can grasp the BSS Color of its own BSS. In this embodiment, the information indicating one BSS Color is 6 In this case, 64 different BSS colors can be expressed, but 62 are normally used BSS colors, and of the remaining two, one is a BSS color used only in special cases (called a special BSS color), and the other indicates that the BSS color is null. This special BSS color is expressed, for example, as 6 bits, 111111, and to indicate null, it is 000000. This means that there are 62 ways other than 111111 and 000000. This is the BSS Color that is typically used to distinguish between an SS and an adjacent BSS.

[0031] After receiving the beacon frame and recognizing the AP, the STA performs authentication and association procedures with the AP. The IEEE 802.11 system uses the Distributed Coordination Function (DCF) and Point Coordination Function (PCF) as media access methods, and their extensions. Although a Hybrid Coordination Function (HCF) based on the DCF has been defined, an overview of transmission operations based on the DCF will be explained here.

[0032] In DCF, before starting communication, APs and STAs perform carrier sense (CS) to check the usage status of wireless channels around their own devices, and then select the expected frequency on the wireless channel. When a station receives a signal with a received power higher than a predetermined Clear Channel Assessment level (CCA level), it postpones frame transmission on that wireless channel. Hereinafter, a state in which a signal with a received power equal to or higher than the CCA level is detected on that wireless channel is called a busy state, and a state in which a signal with a received power equal to or higher than the CCA level is not detected is called an idle state. In other words, if the station is in a busy state during the carrier sense period, it postpones transmission, and if the station is in an idle state, it proceeds to transmission operation. However, a mechanism is provided in which transmission is suspended for a random backoff time that is randomly set before starting transmission, thereby avoiding frame collisions caused by other transmitting stations transmitting frames at the same timing.

[0033] A receiving station that receives a frame transmitted in this manner reads the PHY header of the frame and demodulates the received frame. Then, by reading the MAC header of the demodulated signal, it can determine whether the frame is addressed to its own device. At this time, the receiving station can determine whether the communication is within its own BSS based on the BSS Color included in the U-SIG in the PHY header. If the communication is not within its own BSS, it can stop demodulating subsequent frames. If the receiving station determines that the received frame is addressed to its own device and can demodulate the frame without error, it sends an Ack frame to the transmitting station indicating that the frame was received correctly, and the communication sequence ends.

[0034] If the STA determines that the received frame is not addressed to the STA, it sets a network allocation vector (NAV) based on the length of the frame included in the PHY header, etc. No transmission is attempted during the period set in V. In other words, the STA performs the same operation as when it determines that the wireless channel is busy by physical CS during the period set in NAV, so communication control by NAV is also called virtual carrier sense (virtual CS). In addition to being set based on information contained in the PHY header, NAV is also set by RTS and CTS frames introduced to solve the hidden terminal problem.

[0035] In this embodiment, JT (also called cooperative transmission) is targeted, in which APs of adjacent BSSs cooperate with each other to transmit the same data for a specific STA using the same resources. When JT is performed, first, one of the APs becomes the Coordinator AP that leads the cooperation. The Coordinated AP then notifies the Coordinated AP with which it is cooperating that it will perform JT. This notification is made using a trigger frame, but it is not limited to this and can also be made using other control frames. When a Coordinated AP receives a trigger frame indicating that it will perform JT, it performs operations such as synchronizing with the Coordinator AP based on the trigger frame.

[0036] The JT methodology adopted in this embodiment is a method for transmitting the same data intended for a specific STA using the same resources in cooperation with multiple APs. Data intended for the destination STA must also be shared between the APs in advance. This data sharing is also performed by transmission from the Coordinator AP to the Coordinated AP, using a trigger frame that includes the data intended for the STA, information about the destination STA, and information about the resources used for transmission. In other words, JT in this embodiment is basically performed for STAs located within the BSS of the Coordinator AP. After sharing the information required for JT between the Coordinator AP and the Coordinated AP, the same frame intended for the destination STA is simultaneously transmitted from both APs. The destination STA receives the same frame transmitted from multiple APs simultaneously, improving reception quality.

[0037] In this embodiment, information sharing between APs is performed by wireless transmission between APs, which is generally called wireless backhaul. As described above, a simplified explanation has been given of information sharing over wireless backhaul for JT, and a trigger frame is used for this purpose. However, this is not limited to this, and more processing may be included, and a configuration using a control frame other than a trigger frame may also be used. Furthermore, in the above, JT in this embodiment is basically performed for STAs located within the BSS of the Coordinator AP. However, this is not limited to this, and the AP that becomes the Coordinator AP and the STA for which JT is performed may be determined based on other factors. [1. First embodiment]

[0038] 3 is a diagram showing an example of a wireless communication system according to this embodiment. Wireless communication system 3003-1 includes wireless communication device 3001-1 and wireless communication devices 3002-1 to 3002-2. Wireless communication device 3001-1 will also be referred to as AP 3001-1, and wireless communication devices 3002-1 to 3002-2 will also be referred to as STAs 3002-1 to 2. AP 3001-1 and STAs 3002-1 to 3002-2 are wirelessly connected, and are able to transmit and receive PPDUs to and from each other. The wireless communication system according to this embodiment also includes wireless communication system 3003-2. Wireless communication system 3003-2 includes wireless communication device 3001-2 and wireless communication devices 3002-3 to 3002-4. Wireless communication device 3001-2 is also referred to as AP 3001-2, and wireless communication devices 3002-3 to 3002-4 are also referred to as STAs 3002-3 to 3002-4. AP 3001-2 and STAs 3002-3 to 3002-4 are wirelessly connected, and are able to transmit and receive PPDUs to and from each other. Wireless communication system 3003-1 and wireless communication system 3003-2 form different BSSs, and wireless communication system 3003-1 is also referred to as BSS 3003-1, and wireless communication system 3003-2 is also referred to as BSS 3003-2. The BSS Color in BSS 3003-1 is also referred to as BSS 3003-2. The BSS Color in BSS 3003-1 is designated Color 1, and the BSS Color in BSS 3003-2 is designated BSS Color 2. However, here, BSS Color 1 and BSS Color 2 are assumed to be different BSS Colors from the 62 BSS Colors normally used to distinguish the local BSS from adjacent BSSs, excluding the special BSS Color 111111 and 000000, which indicates that the BSS Color is null. Note that each of BSS 3003-1 and 3003-2 may further include multiple wireless communication devices. is.

[0039] An example of frame transmission and reception in the wireless communication system shown in FIG. 3 is shown in FIG. 4. For simplicity, the following description will focus on the main frames and signals in this embodiment, with each frame consisting of its necessary signals, including the legacy preamble. The description will be made on the assumption that control signals and the like are correctly demodulated. Furthermore, descriptions of control frames such as ACK, NACK, RTS, and CTS, as well as descriptions of operations such as carrier sense, will be omitted. FIG. 4 shows examples of transmission and reception in each of BSSs 3003-1 and 3003-2. For simplicity, each frame in FIG. 4 shows only the BSS Color contained in that frame, but in reality, other signals will be included as well. The solid arrows in FIG. 4 schematically indicate transmission to the destination, and the dashed arrows schematically indicate reception at a location other than the destination. Here, to perform JT for STA 3002-1, AP 3001-1 becomes the Coordinator AP that leads the JT, and AP 3001-2 becomes the Coordinated AP in response to this. As shown in Fig. 4, AP 3001-1 in this embodiment first notifies AP 3001-2 via the wireless backhaul of a frame 4001 containing control information required for JT. This frame 4001 includes at least information identifying the terminal that is the target of JT (information identifying STA 3002-1 in this case), resources (frequency and time) to be used when performing JT, information on BSS Color 1 indicating the BSS Color of BSS 3003-1, and information on a special BSS Color that is notified together with BSS Color 1 during JT, and further includes data for STA 3002-1 to transmit during JT. As described above, this frame 4001 may be transmitted as a trigger frame. In this manner, in this embodiment, two BSS Colors, the BSS Color of the Coordinator AP and the special BSS Color, are exchanged in advance between APs as information required for JT. AP 3001-2, which receives frame 4001, can obtain the information required for JT and prepare a frame for performing JT using the specified resources.

[0040] Next, AP 3001-1 transmits beacon frame 4002-1 in BSS 3003-1. A beacon frame is a management frame periodically broadcast from an AP in each BSS, and this beacon frame 4002-1 includes information on two BSS colors, BSS Color 1 and a special BSS color, as information indicating the BSS color. This beacon frame 4002-1 is received by STA 3002-1 and STA 3002-2 in BSS 3003-1, and STA 3002-1 and STA 3002-2 can obtain information on the two BSS colors, BSS Color 1 and the special BSS color. In this way, the AP in this embodiment broadcasts information on the two BSS colors, the BSS color of the BSS to which it originally belongs and the special BSS color, within the BSS using a beacon frame. The same applies to AP 3001-2. AP 3001-2 transmits a beacon frame 4002-2, but the beacon frame 4002-2 contains the BSS The information indicating the color includes information on two BSS colors, BSS Color 2 and a special BSS Color. This beacon frame 4002-2 is received by STA 3002-3 and STA 3002-4 in BSS 3003-2, and STA 3002-3 and STA 3002-4 can acquire information on the two BSS colors, BSS Color 2 and the special BSS Color. In this way, each AP broadcasts information on two BSS colors in the beacon frame before JT is performed, but the first BSS Color is the BSS Color of the BSS to which it originally belongs, and the subsequent BSS Colors are special BSS Colors. Note that although beacon frames 4001-1 and 4001-2 are depicted as being transmitted simultaneously in FIG. 4, the transmission timings may be different.

[0041] Next, JT from AP 3001-1 and AP 3001-2 to STA 3002-1 is performed using the time and frequency resources specified in frame 4001. In FIG. 4, this JT is performed by transmitting a PPDU (data frame) for STA 3002-1 using frames 4003-1 and 4003-2. Here, frames 4003-1 and 4003-2 are frames configured with exactly the same information, and two BSS Colors, BSS Color 1 and a special BSS Color, are included in the PHY header as information indicating the BSS Color, followed by information indicating the destination STA 3002-1 and data addressed to STA 3002-1 in the MAC header. In this way, by transmitting frames configured with all the same information, including the BSS Color, using the same resources, these are combined and received by STA 3002-1, thereby improving the reception characteristics at STA 3002-1.

[0042] Frames 4003-1 and 4003-2 are frames for JT intended for STA 3002-1, but the following describes the operation when these frames are received by a STA other than STA 3002-1. First, when STA 3002-2 receives a frame in which frames 4003-1 and 4003-2 are combined, it determines that, like STA 3002-1, it contains information on two BSS colors: BSS Color 1 and a special BSS color. This BSS color information matches the BSS color information previously broadcast by AP 3001-1 in beacon frame 4002-1, and in particular, it contains information on BSS Color 1 for its own BSS, BSS 3003-1. Therefore, STA 3002-2 determines that the frame in which frames 4003-1 and 4003-2 are combined is a transmission within its own BSS, BSS 3003-1. Based on this determination, STA3002-2 demodulates up to the information regarding the destination STA in the MAC header, but because the information regarding the destination STA indicates STA3002-1, it determines that the frame is not addressed to itself and stops demodulating subsequent signals including data signals. Also, based on the determination that the frame combining frames 4003-1 and 4003-2 is for transmission within its own BSS, it is determined that transmission using the corresponding resources is currently taking place within its own BSS, BSS3003-1, and therefore operates to refrain from transmission using resources that overlap with frames 4003-1 and 4003-2.

[0043] Furthermore, when STA3002-3 and STA3002-4 in BSS3003-2 receive a frame formed by combining frames 4003-1 and 4003-2, the following operations are performed at these STAs. Because the same operations are performed at STA3002-3 and STA3002-4, the operation of STA3002-3 will be described here. When STA3002-3 receives a frame formed by combining frames 4003-1 and 4003-2, it determines that the frame contains two BSS Color information items, BSS Color 1 and a special BSS Color, just like STA3002-1 and STA3002-2. Although this BSS Color information does not completely match the BSS Color information previously broadcast in beacon frame 4002-2 by AP3001-2, it contains the special BSS Color information previously broadcast in beacon frame 4002-2, and therefore determines that JT involving AP3001-2 is being performed. In other words, since it is clear that JT involving AP 3001-2 is taking place, even though it is not a transmission within its own BSS, BSS 3003-2, STA 3002-3 operates to refrain from transmission using resources that overlap with frames 4003-1 and 4003-2. Also, by determining that the frame combining frames 4003-1 and 4003-2 is not a transmission within its own BSS, STA 3002-3 can stop demodulating the signal that follows the BSS Color information.

[0044] In this way, in the beacon frame 4002-1, BSS Color1 and the special BS In order to perform JT, the AP transmits information on two BSS Colors, such as BSS Color 1 and BSS Color 2, broadcast in beacon frame 4002-1, BSS Color 2 and special BSS Color, broadcast in beacon frame 4002-2, and frames 4003-1 and 4003-2 transmitted by JT transmit information on two BSS Colors, BSS Color 1 and special BSS Color, respectively. STAs that are the target of JT can receive a signal that combines the same frames (frames 4003-1 and 4003-2) transmitted from different APs, and STAs within BSS 3003-1 other than the STAs that are the target of JT determine that frames 4003-1 and 4003-2 are transmissions within their own BSS, and can avoid frame collisions by refraining from transmissions using resources that overlap with frames 4003-1 and 4003-2. Furthermore, the STA in BSS 3003-2 determines that frames 4003-1 and 4003-2 are frames generated by JT involving AP 3001-2, even though they are not transmissions within its own BSS, and can avoid frame collisions by refraining from transmissions using resources that overlap with frames 4003-1 and 4003-2. In this way, in both BSSs involved in JT, it is possible to prevent other STAs from transmitting using resources that overlap with frames generated by JT, thereby avoiding frame collisions.

[0045] While JT can be performed through such transmission and reception, in this embodiment, transmission and reception within individual BSSs are assumed to occur following JT. Here, in BSS 3003-2, transmission from AP 3001-2 to STA 3002-3 is assumed to occur, and this frame is shown as frame 4004-2 in Fig. 4. The PHY header of frame 4004-2 contains two BSS Color information items: BSS Color 2 and information indicating that the BSS Color is null. When this frame is received by STA 3002-3, which is the destination, STA 3002-3 determines, based on the fact that BSS Color 2 is included in the BSS Color, that this is a transmission within BSS 3003-2 to which STA 3002-3 belongs, and continues demodulation. Based on the destination information included in the MAC header, STA 3002-3 determines that this is a transmission addressed to itself, and demodulates the data portion. Furthermore, when this frame 4004-2 is received by STA3002-4, another STA within BSS3003-2, it determines based on the information in BSS Color2 that the transmission is within BSS3003-2 to which it belongs, and continues demodulation, but determines based on the destination information included in the MAC header that the transmission is not addressed to itself, and does not demodulate the data portion.In this case, because it can determine that transmission is occurring within BSS3003-2 to which it belongs, even if STA3002-4 has data to send, it operates to refrain from transmission using the same resources as frame 4004-2.

[0046] If this frame 4004-2 is also received by STA3002-1, a STA within BSS3003-1, STA3002-1 determines from the information indicating BSS Color2 and Null contained in frame 4004-2 that frame 4004-2 is not a transmission within BSS3003-1 to which STA3002-1 belongs, and stops demodulating subsequent frames. Here, since it has been determined that frame 4004-2 is not a transmission within BSS3003-1, if STA3002-1 itself has data to transmit, it can transmit using the same resources as frame 4004-2, regardless of the presence of frame 4004-2. In Figure 4, this is shown as frame 4004-1 transmitted from STA3002-1 to AP3001-1. As shown in Figure 4, the PHY header of frame 4004-1 contains information indicating that BSS Color1 and BSS Color are null, and AP3001-1 determines that the transmission is within BSS3003-1 and continues demodulation. It then determines from the subsequent destination information that the transmission is addressed to itself and demodulates the data portion. On the other hand, when this frame 4004-1 is received by STA3002-2, another STA within BSS3003-1, it determines that the BSS Color to which it belongs is addressed based on the information in BSS Color1. It determines that the transmission is within SS3003-1 and continues demodulation, but determines that the transmission is not addressed to itself based on the destination information included in the MAC header and does not demodulate the data portion. Note that when STA3002-1 transmits frame 4004-1, since it is transmitted using the same resources as frame 4004-2, it may transmit frame 4004-1 after performing transmission power control from the perspective of reducing interference to adjacent BSSs.

[0047] If, after the above transmission, there is no longer any need for JT in any AP, at the next beacon frame broadcast, each AP broadcasts two BSS Color information within the BSS: the BSS Color of the BSS to which it originally belonged, and information indicating that the BSS Color is null. In FIG. 4, these beacon frames are represented by frames 4005-1 and 4005-2. After the BSS Color information is updated by beacon frames 4005-1 and 4005-2, the two BSS Colors broadcast in the beacon frame are also included in the PHY header of the PPDU frame (data frame) transmitted from each AP to individual STAs within the BSS to which it belongs. The STAs receiving these frames will each receive two BSS Colors, one of which indicates null, and will essentially only use the information indicating the BSS Color of their own BSS, which they use to distinguish between frames from their own BSS and those of adjacent BSSs. Furthermore, the PHY headers of frames transmitted from the STAs will also contain the two BSS Colors reported in the beacon frames.

[0048] In this way, in this embodiment, when JT is performed, each AP is connected to the BSS of the BSS to which it originally belonged. In this system, information on two BSS Colors, the BSS Color and the special BSS Color, is broadcast within the BSS using a beacon frame. Then, when actual JT is performed, APs coordinate to transmit the same data frame (PPDU) containing information on both the BSS Color of the BSS to which the STA belongs and the special BSS Color. When performing individual transmissions in each BSS, the AP or STA transmits a frame containing information indicating the BSS Color to which it belongs and null in the PHY header. This BSS Color setting and the receiver's decision based on the BSS Color information eliminate the need to update or reset the BSS Color information using multiple periodically broadcast beacon frames, such as the BSS Color for JT and the BSS Color for individual transmissions. This improves reception characteristics at STAs through JT, and distinguishes between transmissions within the BSS and those in adjacent BSSs during individual transmissions within the BSS, enabling frequency utilization efficiency to be improved. In other words, it is possible to transmit at least one JT frame and one individual frame within the BSS separately within a time period within the beacon frame period.This type of transmission makes it possible to achieve both improved reception characteristics through JT and improved frequency reuse based on BSS Color.

[0049] Next, the main configurations of the AP and STA in this embodiment are shown in Figures 5 and 6, respectively. As shown in Figure 5, the AP in this embodiment is made up of a wireless control unit 5001, a wireless communication unit 5002, and an antenna unit 5003. Wireless control unit 5001 includes a JT control unit 5001-1 and a BSS Color control unit 5001-2, and wireless communication unit 5002 includes a frame generation unit 5002-1, a wireless transmission unit 5002-2, a wireless reception unit 5002-3, and a signal demodulation unit 5002-4.

[0050] Among these, the JT control unit 5001-1 determines whether to perform JT and, based on the result, controls the information sharing via wireless backhaul to the Coordinated AP when it becomes a Coordinator AP. Also, when it becomes a Coordinated AP based on information from other APs, it controls the information shared by the other APs. The control unit 5001-2 controls the transmission of a frame composed of the BSS Color and the special BSS Color using the resources notified by the other AP. The result of the decision on whether to perform JT is notified to the BSS Color control unit 5001-2. The BSS Color control unit 5001-2 also holds information indicating the BSS Color of its own BSS, the special BSS Color, and information indicating that the BSS Color is null, and determines and controls which BSS Color information to transmit at the appropriate time, and notifies the wireless communication unit 5002 of the BSS Color information to be transmitted. In other words, when the BSS Color control unit 5001-2 is the Coordinator AP, when sharing information required for JT with the Coordinated AP or during actual JT transmission, the control unit 5001-2 selects information indicating the BSS Color of its own BSS and information indicating the special BSS Color, and when performing individual transmission to a STA in its own BSS other than JT, the control unit 5001-2 selects information indicating the BSS Color of its own BSS and information indicating null, and notifies the wireless communication unit 5002 of the selected BSS Color information. Although details are omitted here, the wireless control unit 5001 notifies the wireless communication unit 5002 of appropriate information at appropriate timing so that control information, data, etc. are transmitted appropriately.

[0051] The frame generation unit 5002-1 in the wireless communication unit 5002 generates frames to be transmitted, and the information, signals, and so on required for this are notified from the wireless control unit 5001. In particular, in this embodiment, the information indicating the BSS Color added during frame transmission changes adaptively, so the BSS Color control unit 5001-2 receives appropriately selected BSS Color information at the appropriate timing and adds the received BSS Color information to the PHY header. However, it is not necessary to configure the unit to receive all of the information and signals required to configure a frame from the wireless control unit 5001; for example, predetermined signals such as legacy preambles may be stored in the frame generation unit 5002-1. The frame generation unit 5002-1 also performs signal processing such as modulation and IFFT (conversion to OFDM signals), and the frames generated by the frame generation unit 5002-1 are sent to the wireless transmission unit 5002-2. Radio transmitting section 5002-2 performs signal processing (D / A conversion, filtering, frequency conversion to radio frequency, etc.) to convert the signal into a radio signal required for radio transmission, and the radio signal is then transmitted from antenna section 5003.

[0052] Furthermore, the radio signal received by the antenna unit 5003 is sent to the radio receiving unit 5002-3, where it is converted from a radio signal to a digital signal (frequency conversion to a baseband signal, filtering, A / D conversion, etc.). The frame converted into a digital signal by the radio receiving unit 5002-3 is sent to the subsequent signal demodulation unit 5002-4, where it undergoes processes such as FFT, propagation channel estimation using a part of the preamble (LTF), channel equalization and demodulation using the propagation channel estimation result, and error correction decoding, thereby sequentially extracting information contained in the frame. The information sequentially extracted in this manner includes BSS Color information and data, etc., and this information is sent to the radio control unit 5001. Note that in this embodiment, components for measuring the received power level for carrier sensing are omitted, but these components may also be provided in the signal demodulation unit 5002-4 or the radio communication unit 5002.

[0053] Information extracted from the received signal in wireless communication unit 5002 is sent sequentially to wireless control unit 5001, and among the information sent to wireless control unit 5001, BSS Color information is sent to BSS Color control unit 5001-2, which determines whether the BSS Color information sent from the sender matches the BSS Color information it holds. Here, if the sender is a STA and the BSS Color information sent from the STA differs from the BSS Color information in its own BSS, that is, if the BSS Color information sent from the STA indicates the BSS Color of another BSS, the signal is The frame generation unit 5002-1 may notify the signal demodulation unit 5002-4 that it will stop demodulating the signals following the frame in question. Also, if the sender is the Coordinator AP and the received frame is a frame for performing JT (frame 4001 in FIG. 4), the BSS Color information included in this frame is information required for JT, and is therefore stored in the BSS Color control unit 5001-2. Also, all information required for JT is sent to the JT control unit 5001-1, which, based on the notified information, prepares for JT, such as checking the resources to be used in JT. Then, at the timing to perform JT, the information to be transmitted by JT is sent to the frame generation unit 5002-1, where it is generated as a frame and transmitted via the subsequent radio transmission unit 5002-2 and antenna unit 5003.

[0054] 6, the STA in this embodiment is made up of a wireless control unit 6001, a wireless communication unit 6002, and an antenna unit 6003. The wireless control unit 6001 includes a BSS Color determination unit 6001-1, and the wireless communication unit 6002 includes a frame generation unit 6002-1, a wireless transmission unit 6002-2, a wireless reception unit 6002-3, and a signal demodulation unit 6002-4. In this configuration, although there are differences between the AP and the STA, the frame generation unit 6002-1, the wireless transmission unit 6002-2, the wireless reception unit 6002-3, and the signal demodulation unit 6002-4 basically perform the same operations as the respective units shown in FIG. 5, and therefore detailed description thereof will be omitted here. On the other hand, the wireless control unit 6001 has a different configuration from the wireless control unit 5001 in Fig. 5. This is because, first, JT in this embodiment is a technology for transmitting the same frame for a specific STA from multiple APs, and the STA does not perform transmission by JT, so a configuration like the JT control unit 5001-1 is not necessary. Furthermore, the wireless control unit 6001 includes a BSS Color determination unit 6001-1, which holds BSS Color information notified from the AP via a beacon frame and notifies the frame generation unit 6002-1 of the BSS Color information so as to add the BSS Color information notified from the AP to the PHY header when transmitting its own PPDU (data frame). Furthermore, when receiving a PPDU, the unit acquires the BSS Color information added to the PHY header of the PPDU and compares it with the BSS Color information it holds. If the BSS Color at the beginning matches the BSS Color information of its own BSS, it determines that the PPDU is a frame within its own BSS; otherwise, it determines that the PPDU is a frame within another BSS. If the second BSS Color is a special BSS Color, the PPDU is determined to be a frame transmitted by JT, and if it is null, it is determined to be an individual transmission frame in another BSS, not a frame transmitted by JT. Based on this determination, if it is determined that the received frame is a frame transmitted by JT, control can be performed to refrain from transmission using resources that overlap with the frame in question.If it is determined that the frame is not a JT frame but an individual transmission frame in another BSS, control can be performed to enable transmission using resources overlapping with the frame in question. Also, if it is determined that the frame is addressed to a destination in another BSS, regardless of whether it is a JT frame, it can be processed to stop demodulating the signal following the frame in question.

[0055] By configuring the AP and STA as described above, it becomes possible to select and notify the BSS Color depending on whether JT is implemented, and to appropriately control according to the notified BSS Color information, thereby transmitting and receiving frames and exchanging necessary data as shown in Figure 4. Note that when transmitting using JT in the STA, JT can also be realized in the STA by configuring the STA in the same way as the AP as shown in Figure 5.

[0056] In this embodiment, information on two BSS Colors is included in a frame and transmitted. However, it is not necessary to always include two BSS Color information pieces, and it may be as shown in Figure 7. Figure 7 shows the same frame transmission and reception as Figure 4, with only the BSS Color information included in some frames being different, so detailed explanation of the same parts as Figure 4 will be omitted.

[0057] First, frame 7001, like frame 4001, is a frame that transmits control information required for JT to the Coordinated AP via the wireless backhaul, but while frame 4001 includes two BSS Color information, the BSS Color of the Coordinator AP and a special BSS Color, frame 7001 is configured to include only special BSS Color information. Next, beacon frame 7002-1 is a management frame like beacon frame 4002-1, and the information indicating the BSS Color also includes information on two BSS Colors, BSS Color 1 and a special BSS Color. The same is true for beacon frame 7002-2, which, like beacon frame 4002-2, includes information on two BSS Colors, BSS Color 2 and a special BSS Color, as information indicating the BSS Color. In this way, the BSS Color information transmitted and received between APs performing JT is only the special BSS Color information, but in the beacon frames broadcast from each AP within its own BSS, the BSS Color of its own BSS is also added before the special BSS Color, and information on two BSS Colors is broadcast.

[0058] Next, JT from AP 3001-1 and AP 3001-2 to STA 3002-1 is performed using the time and frequency resources specified in frame 7001. In FIG. 7, this JT is performed by transmitting a PPDU (data frame) for STA 3002-1 using frames 7003-1 and 7003-2. Here, frames 7003-1 and 7003-2 are frames configured with exactly the same information, and special BSS Color information is included in the PHY header as information indicating the BSS Color, followed by information indicating the destination STA 3002-1 and data addressed to STA 3002-1 in the MAC header. In frames 4003-1 and 4003-2, information on two BSS Colors, BSS Color 1 and special BSS Color, is included in the PHY header; however, as shown in frames 7003-1 and 7003-2, only special BSS Color information may be included in the PHY header. Frames 7003-1 and 7003-2 are frames configured with exactly the same information, and by transmitting them using the same resources, they are combined and received by STA3002-1, thereby improving the reception characteristics at STA3002-1.

[0059] Frames 7003-1 and 7003-2 are frames for JT addressed to STA 3002-1, but the following describes the operation when these frames are received by a STA other than STA 3002-1. First, when STA 3002-2 receives a frame in which frames 7003-1 and 7003-2 are combined, it determines, as with STA 3002-1, that it contains special BSS Color information. Since this special BSS Color information is included in the BSS Color information previously broadcast by AP 3001-1 in beacon frame 7002-1, STA 3002-2 determines that the frame in which frames 7003-1 and 7003-2 are combined is a frame for JT associated with its own BSS. Based on this determination, STA 3002-2 demodulates up to the information regarding the destination STA in the MAC header. However, since the information regarding the destination STA indicates STA 3002-1, it determines that the frame is not addressed to itself and stops demodulating subsequent signals, including data signals. In addition, the frame in which frames 7003-1 and 7003-2 are combined is determined to be a frame by JT related to the own BSS, and frames 7003-1, It operates to refrain from transmission using resources that overlap with 7003-2.

[0060] Furthermore, when STA3002-3 and STA3002-4 in BSS3003-2 receive a frame formed by combining frames 7003-1 and 7003-2, the following operations are performed at these STAs. Here, because both STA3002-3 and STA3002-4 basically perform the same operations as STA3002-2, only a brief explanation of the operation of STA3002-3 will be given here. When STA3002-3 receives a frame formed by combining frames 7003-1 and 7003-2, it determines that special BSS Color information is included, just like STA3002-1 and STA3002-2. Since this special BSS Color information is included in the BSS Color information previously broadcast by AP3001-2 in beacon frame 7002-2, STA3002-3 determines that the frame formed by combining frames 7003-1 and 7003-2 is a frame based on the JT associated with its own BSS. Based on this determination, STA3002-3 demodulates up to the information regarding the destination STA in the MAC header, but because the information regarding the destination STA indicates STA3002-1, it determines that the frame is not addressed to itself and stops demodulating subsequent signals including data signals.Furthermore, based on the determination that the frame combining frames 7003-1 and 7003-2 is a frame based on a JT associated with its own BSS, it operates to refrain from transmission using resources that overlap with frames 7003-1 and 7003-2.

[0061] In this way, beacon frame 7002-1 broadcasts information on two BSS colors, BSS Color 1 and special BSS Color, and beacon frame 7002-2 broadcasts information on two BSS colors, BSS Color 2 and special BSS Color, whereas frames 7003-1 and 7003-2 transmitted by JT transmit only information on the special BSS Color. Although the BSS Color broadcast in the beacon frame does not completely match the BSS Color added to the frame transmitted by JT, one of the two BSS Colors broadcast in the beacon frame is the BSS Color added to the frame transmitted by JT. Because it is Color, STAs other than the STA that is the target of JT will determine that frames 7003-1 and 7003-2 are JT transmissions related to their own BSS, and by refraining from transmitting using resources that overlap with frames 7003-1 and 7003-2, frame collisions can be avoided.

[0062] Next, following JT, a case where transmission and reception are performed within an individual BSS will be described. Frame 7004-2 in Fig. 7 corresponds to frame 4004-2 in Fig. 4, but the PHY header of frame 7004-2 includes information about BSS Color 2. When this frame is received by STA3002-3, which is the destination, STA3002-3 determines that the transmission is within BSS3003-2 to which it belongs and continues demodulation, but determines that the transmission is addressed to itself based on the destination information included in the MAC header and demodulates the data portion. Also, when this frame 7004-2 is received by STA3002-4, another STA within BSS3003-2, it determines that the transmission is within BSS3003-2 to which it belongs and continues demodulation, but determines that the transmission is not addressed to itself based on the destination information included in the MAC header and does not demodulate the data portion. At this time, it can be determined that transmission is taking place within BSS 3003-2 to which it belongs, so even if STA 3002-4 has data to send, it operates to refrain from transmission using the same resources as frame 7004-2.

[0063] When this frame 7004-2 is also received by STA3002-1, which is a STA within BSS3003-1, STA3002-1 determines from the information on BSS Color2 included in frame 7004-2 that frame 7004-2 is the same as the BSS300 to which it belongs. 3-1, and stops demodulating subsequent frames. Here, because it has been determined that frame 7004-2 is not a transmission within BSS 3003-1, if STA 3002-1 itself has data to transmit, it can transmit using the same resources as frame 7004-2, regardless of the presence of frame 7004-2. In Figure 7, this is shown as frame 7004-1 transmitted from STA 3002-1 to AP 3001-1. As shown in Figure 7, the PHY header of frame 7004-1 contains information about BSS Color 1, and AP 3001-1 determines that the transmission is within BSS 3003-1 and continues demodulation. It then determines from the subsequent destination information that the transmission is addressed to itself and demodulates the data portion. On the other hand, when this frame 7004-1 is received by STA3002-2, another STA within BSS3003-1, it determines based on the information in BSS Color1 that the transmission is within BSS3003-1 to which it belongs, and continues demodulation, but determines based on the information about the destination included in the MAC header that the transmission is not addressed to itself, and does not demodulate the data portion. Note that when STA3002-1 transmits frame 7004-1, since it is transmitted using the same resources as frame 7004-2, it may be possible to transmit frame 7004-1 after performing transmission power control, from the perspective of reducing interference to adjacent BSSs.

[0064] Note that, if there is no longer a need for JT in either AP after the above transmission, when broadcasting the next beacon frame (beacon frames 7005-1, 7005-2), each AP broadcasts two BSS Color information within the BSS in the beacon frame: the BSS Color of the BSS to which it originally belonged, and information indicating that the BSS Color is null. This information indicating null is inserted to adjust the length of the BSS Color information in the beacon frame. In contrast, the PHY header of a PPDU frame transmitted from each AP to an individual STA in the BSS to which it belongs contains only the BSS Color information of the BSS to which it belongs. STAs receiving these frames use the received BSS Color information to distinguish between frames from their own BSS and frames from adjacent BSSs. Furthermore, the PHY header of a frame transmitted from a STA also contains only the BSS Color information of the BSS to which it belongs.

[0065] As shown in Fig. 7, even if the beacon frame broadcasts information about two BSS Colors, but the PHY headers of other PPDU frames only include information about one BSS Color, the JT improves reception characteristics at the STA, and during individual transmissions within the BSS, the AP and STA distinguish between transmissions within the BSS itself and transmissions within adjacent BSSs, and transmits using resources that overlap with transmissions within adjacent BSSs, thereby improving frequency utilization efficiency. The AP and STA for transmitting and receiving the frames shown in Fig. 7 can be realized with the same configurations as those shown in Figs. 5 and 6, respectively, by changing the method of adding the BSS Color. As a result, while the example of Fig. 4 had a frame configuration that always included information about two BSS Colors, including the PPDU frame, by adding information about only one BSS Color to the PHY headers of the PPDU frames as shown in Fig. 7, the amount of information for one BSS Color in this embodiment is reduced by 6 bits, thereby improving efficiency.

[0066] Furthermore, the BSS Color information added to the frame may be variable. In particular, in the above description, the BSS Color information broadcast by the beacon frame includes information on two BSS Colors, but the information indicating null is essentially unnecessary because it is information inserted to adjust the length of the BSS Color information in the beacon frame, and can be deleted by making the BSS Color information variable. In order to make the BSS Color information variable, separate control information is required to identify whether the BSS Color information included in the frame contains one or two BSS Colors. This is possible by adding 1-bit control information indicating the length (number) of the BSS Color to be added before the BSS Color information. For example, in the beacon frame 7002-1 and the beacon frame 7002-2 in FIG. 7, two BSS Since BSS Color is added, 1-bit control information indicating the length (number) of BSS Color is set to 1, and in beacon frames 7005-1 and 7005-2, one BSS Since it is sufficient to add a Color, the 1-bit control information indicating the length (number) of the BSS Color can be set to 0. This allows the length (number) of the BSS Color to be variable, improving efficiency by reducing the number of unnecessary bits. [2. Second Embodiment]

[0067] In the first embodiment, notification of BSS Color is performed using a trigger frame, a beacon frame (management frame), a data frame (PPDU), etc., and control based on that notification information is shown, but BSS Color information may also be included in other frames. In this embodiment, as an example of such a case, a form is shown in which BSS Color information is included in an RTS, which is one type of control frame, and transmitted. However, BSS Color information may be included not only in an RTS but also in other control frames such as a CTS, and may also be included in management frames other than beacon frames, not just in control frames.

[0068] FIG. 8 shows an example of frame transmission and reception in this embodiment. The basic flow of frame transmission and reception in FIG. 8 is similar to that in FIG. 4 and FIG. 7, but unlike FIG. 4 and FIG. 7, it shows a form including a transmission and reception procedure using RTS and CTS. Similar to FIG. 4 and FIG. 7, FIG. 8 also shows an example of frame transmission and reception in the wireless communication system shown in FIG. 3. However, similar to FIG. 4 and FIG. 7, for the sake of simplicity, only the main frames and signals in this embodiment will be explained, but each frame will be composed of the necessary signals, including the legacy preamble. Furthermore, the explanation will be made on the assumption that control signals and the like are correctly demodulated. Furthermore, descriptions of control frames such as ACK and NACK, and descriptions of operations such as carrier sense will be omitted.

[0069] Frame 8001 in Fig. 8 is a trigger frame for JT, and like frame 7001 in Fig. 7, it contains information about a special BSS Color as the BSS Color. This trigger frame allows information required for JT to be shared between APs. Also, frames 8002-1 and 8002-2 are beacon frames periodically broadcast from APs in each BSS. Like frames 7002-1 and 7002-2 in Fig. 7, frame 8002-1 contains BSS Color 1 and a special BSS Color, and frame 8002-2 contains BSS Color 2 and a special BSS Color. Each BSS contains a color and is broadcast within the BSS.

[0070] Here, frames 8003-1 and 8003-2 are RTS frames containing BSS Color information in this embodiment. These frames are RTS frames transmitted from both APs when AP3001-1 and AP3001-2 perform JT. As shown in FIG. 8, frames 8003-1 and 8003-2 contain special BSS Color information. This special BSS Color is information that has been broadcast in advance within the BSS in frames 8002-1 and 8002-2. Therefore, it is possible to notify in advance by the RTS frame that JT transmission will be performed not only to STA3002-1, which is the target of JT, but also to other STAs that can receive the RTS frame. This allows the STAs in the BSS to operate so as to set NAV, making it possible to prevent JT transmission from being obstructed by other STAs. Note that normally, RTS is Since the RTS is transmitted as a frame within the BSS, it is transmitted from AP 3001-1 to STA 3002-1, but in this embodiment, the same RTS is also transmitted from AP 3001-2 at the same time. This allows the STAs in BSS 3003-2 to receive the RTS with high reception power, and based on the special BSS Color included in this RTS, each STA can understand that a JT will be transmitted soon and set a NAV accordingly, making it possible to more reliably prevent the JT transmission from being obstructed by the STAs in BSS 3003-2.

[0071] Furthermore, frame 8004 is a CTS from STA 3002-1 in response to the RTS of frame 8003-1. Here, the CTS of frame 8004 is assumed not to include information indicating the BSS Color, but this is not limitative, and the CTS may also include information indicating the BSS Color. In this case, the CTS will include the same BSS Color information as the BSS Color included in the RTS.

[0072] After sending and receiving the RTS / CTS for the JT, the actual JT is transmitted, which is represented by frames 8005-1 and 8005-2 in Fig. 8 (8005-1 and 8005-2 are data frames). Note that, since the RTS includes the special BSS Color information, the STAs in each BSS operate (set NAV) so as not to perform individual transmissions using resources that overlap with the JT. However, by transmitting JT frames 8005-1 and 8005-2 that also include the special BSS Color information, it is possible to notify the STAs in each BSS that this frame is a frame for the JT related to their own BSS, and it is possible to ensure that the STAs in each BSS do not transmit using resources that overlap with the JT.

[0073] Through such transmission and reception, JT can be performed via transmission and reception of RTS / CTS. However, in this embodiment, transmission and reception are performed within individual BSSs following JT. Here, in BSS 3003-1, transmission from AP 3001-1 to STA 3002-2 is performed, and prior to transmitting a data frame, RTS / CTS transmission and reception is also performed in advance. This RTS is frame 8006-1, and the CTS is frame 8007-1. Of these, the RTS in frame 8006-1 includes BSS Color information, just like frame 8003-1. However, since this is an individual transmission in BSS 3003-1 rather than JT, BSS Color1 information is included. Then, STA 3002-2, which receives this RTS, returns the CTS shown in frame 8007-1, and AP 3001-1, which receives the CTS, transmits frame 8008-1, which is a PPDU (data frame) for STA 3002-2. In this case, when frame 8006-1 is received by STA3002-1, it can determine from the BSS Color1 information contained in frame 8006-1 that a transmission to another destination within its own BSS will occur, and so STA3002-1 sets its NAV to prevent transmission using overlapping resources, thereby preventing frame collisions within the BSS. Note that frame 8008-1, which is a PPDU intended for STA3002-2, also contains BSS Color1 information.

[0074] When frame 8006-1 is received by a STA in BSS3003-2 during such transmission within BSS3003-1, it can be determined from the information on BSS Color1 contained in frame 8006-1 that the upcoming transmission is not within its own BSS, and if the STA has data to transmit, it can ignore the RTS in frame 8006-1 and proceed to data transmission. In this embodiment, it is assumed that STA3002-3 will transmit data, and first the RTS by STA3002-3 is shown in frame 8006-2. This RTS by STA3002-3 is assumed to be performed using resources that overlap with the transmission within BSS3003-1, ignoring the transmission within BSS3003-1. This frame As shown in frame 8006-2, the RTS from STA3002-3 includes information about BSS Color2, and another STA in BSS3003-2 that receives this can understand that a transmission to another destination within its own BSS will occur soon, so it sets its NAV to prevent transmission using overlapping resources, thereby avoiding frame collisions within the BSS. STA3002-3, which receives this RTS, then returns a CTS as shown in frame 8007-2, and AP3001-2, which receives the CTS, transmits frame 8008-2, which is a PPDU intended for STA3002-3.

[0075] If, after the above transmission, JT is no longer required for any AP, at the next broadcast of periodically broadcast beacon frames (beacon frames 8009-1 and 8009-2), each AP broadcasts two BSS Color information within the BSS in the beacon frame: the BSS Color of the BSS to which it originally belonged, and information indicating that the BSS Color is null. This information indicating null is inserted to adjust the length of the BSS Color information in the beacon frame. In contrast, the PHY header of a PPDU frame transmitted from each AP to an individual STA in the BSS to which it belongs contains only the BSS Color information of the BSS to which it belongs. STAs receiving these frames use the received BSS Color information to distinguish between frames from their own BSS and frames from adjacent BSSs. Furthermore, the PHY header of frames transmitted from a STA also contains only the BSS Color information of the BSS to which it belongs. That is, similarly to the first embodiment, it is possible to transmit at least one frame by JT and at least one individual frame within the BSS separately within a time period within the beacon frame period.

[0076] In the transmission and reception of frames according to the present embodiment as described above, by transmitting an RTS including special BSS Color information from each AP in advance, it is possible to ensure that STAs in each BSS do not transmit using resources that overlap with JT. Furthermore, by transmitting an RTS including the respective BSS Color information in advance during individual transmissions within each BSS, it is possible to distinguish whether the frame to be transmitted is from the own BSS or an adjacent BSS, thereby improving frequency utilization efficiency. The AP and STA that transmit and receive frames according to the present embodiment can be realized with the same configurations as those shown in Figures 5 and 6, respectively. However, the frame generation unit must operate to generate RTS frames and CTS frames that include appropriate BSS Color information. [3. Common to all embodiments]

[0077] The communication device according to the present invention communicates in a frequency band (frequency spectrum) called an unlicensed band, which does not require permission to use from a country or region. The communication device according to the present invention can also be effective in a frequency band called a white band, which is not actually used for the purpose of preventing interference between frequencies despite being granted permission for use by a country or region for a specific service, or in a shared spectrum (shared frequency band) that is expected to be shared by multiple operators.

[0078] The program that runs on the wireless communication device according to the present invention is a program that controls the CPU and the like (a program that makes a computer function) so as to realize the functions of the above-described embodiments of the present invention. Information handled by these devices is temporarily stored in RAM during processing, and then stored in various ROMs or HDDs, and is read, modified, and written by the CPU as necessary. Recording media for storing the program include semiconductor media (e.g., ROM, non-volatile memory cards, etc.), optical recording media (e.g., DVD, MO, MD, CD, BD, etc.), magnetic recording media (e.g., magnetic tape, flexible discs, etc.), and the like. In addition, not only are the functions of the above-described embodiments realized by executing the loaded program, but the functions of the present invention may also be realized by processing in cooperation with an operating system or other application programs based on instructions from the program.

[0079] Furthermore, when distributing the program on the market, the program can be stored and distributed on a portable recording medium, or transferred to a server computer connected via a network such as the Internet. In this case, the storage device of the server computer also falls within the scope of the present invention. Furthermore, part or all of the communication device in the above-described embodiments may be realized as an LSI, which is typically an integrated circuit. Each functional block of the communication device may be individually formed into a chip, or part or all of the functional blocks may be integrated into a chip. When each functional block is formed into an integrated circuit, an integrated circuit control unit that controls them is added. It goes without saying that the present invention also includes cases where programs and setting information are downloaded from a server computer to implement at least part of the functions of the above-described embodiments.

[0080] Furthermore, the integrated circuit method is not limited to LSI, and may be realized by dedicated circuits or general-purpose processors. Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology, it may also be possible to use an integrated circuit based on that technology.

[0081] It should be noted that the present invention is not limited to the above-described embodiments. The wireless communication device of the present invention is not limited to application to mobile station devices, but can of course be applied to stationary or non-mobile electronic devices installed indoors or outdoors, such as AV equipment, kitchen equipment, cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0082] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and designs that do not deviate from the gist of the present invention are also included in the scope of the claims. [Industrial Applicability]

[0083] The present invention is suitable for use in a wireless communication device and a wireless communication system. [Explanation of symbols]

[0084] 3001-1, 3001-2 Wireless communication equipment (AP) 3002-1~3002-4 Wireless communication equipment (STA) 3003-1, 3003-2 Wireless Communication System (BSS) 4001 Trigger Frame 4002-1, 4002-2, 4005-1, 4005-2 beacon frames 4003-1, 4003-2 PPDU frame by JT 4004-1, 4004-2 PPDU frames in individual BSSs 5001 Radio control unit 5001-1 JT control section 5001-2 BSS Color control unit 5002 Wireless Communication Department 5002-1 Frame generation unit 5002-2 Radio transmitter 5002-3 Radio receiver 5002-4 Signal demodulation section 5003 Antenna part 6001 Radio control unit 6001-1 BSS Color judgment section 6002 Wireless Communication Department 6002-1 Frame generation unit 6002-2 Radio transmitter 6002-3 Radio receiver 6002-4 Signal demodulation section 6003 Antenna part 7001 Trigger Frame 7002-1, 7002-2, 7005-1, 7005-2 Beacon Frame 7003-1, 7003-2 PPDU frame by JT 7004-1, 7004-2 PPDU frames in individual BSSs 8001 Trigger Frame 8002-1, 8002-2, 8009-1, 8009-2 beacon frames 8003-1, 8003-2, 8006-1, 8006-2 RTS frames 8004, 8007-1, 8007-2 CTS Frames PPDU frame by 8005-1, 8005-2 JT PPDU frames in individual BSSs (8008-1 and 8008-2)

Claims

1. Establishing one or more wireless communication devices and a wireless communication service basic service (BSS), a wireless access point device that controls communication within a management range to perform wireless communication with the wireless communication device, and that cooperates with another wireless access point device that controls a management range different from the management range that the wireless access point device controls to perform cooperative transmission in which the same signal addressed to the specific wireless communication device is transmitted using the same wireless resource; a cooperative transmission control unit that determines whether or not to perform the cooperative transmission and controls notification of information necessary for the cooperative transmission; an identifier control unit that controls information on an identifier for distinguishing the management range that it controls from other management ranges; The identifier control unit controls the information of the identifier so that a management frame including information of two different identifiers for distinguishing the management range controlled by the unit from other management ranges is notified to the wireless communication device within the management range controlled by the unit, and adds information of at least one or more different identifiers to a data frame in the cooperative transmission and a data frame in the case where the cooperative transmission is not performed, and transmits the data frame. A wireless access point device characterized by:

2. The management frame is a frame that is periodically transmitted for each management range, At least one data frame for the cooperative transmission and at least one data frame for the case where the cooperative transmission is not performed are transmitted within a period of the management frame.

2. The wireless access point device according to claim 1.

3. the identifiers to be added to the data frame in the cooperative transmission and the data frame in the case where the cooperative transmission is not performed are two identifiers each, One of the identifiers is different between the data frame in the cooperative transmission and the data frame in the case where the cooperative transmission is not performed.

3. The wireless access point device according to claim 2.

4. The different identifiers added to the data frame in the cooperative transmission and the data frame in the case where the cooperative transmission is not performed are each one identifier.

3. The wireless access point device according to claim 2.

5. At least one of the identifiers is added to a control frame different from the management frame and transmitted.

2. The wireless access point device according to claim 1.

6. The control frame is a frame transmitted prior to transmission of the data frame, and is transmitted by adding the identifier different from that of the data frame in the cooperative transmission and that of the data frame in the case where the cooperative transmission is not performed.

6. The wireless access point device according to claim 5.

7. A first wireless communication system that sets a wireless communication service management range (BSS) and controls communications within the management range. a wireless communication device that wirelessly communicates with a first wireless access point device and receives the same signal transmitted by the first wireless access point device and a second wireless access point device that controls a management range different from the first wireless access point device and that cooperates with the second wireless access point device and that controls a management range different from the first wireless access point device, using the same wireless resource; receiving a management frame including information on two different identifiers for distinguishing the management range from other management ranges; an identifier determination unit that selects one of the two different received identifiers; A wireless communication device characterized in that information of the identifier selected by the identifier determination unit is added to a data frame and transmitted.

8. A control frame transmitted prior to transmission of the data frame includes: The information of the selected identifier is added and transmitted.

8. The wireless communication device according to claim 7.

9. A wireless access point that sets up a wireless communication service management range (BSS) and controls communications within that range. a wireless communication system including an access point device and one or more wireless communication devices that communicate with the wireless access point device within the management range, the wireless communication system performing cooperative transmission in which two different wireless access point devices transmit the same signal addressed to a specific wireless communication device using the same wireless resource, broadcasting a management frame including information on two different identifiers for distinguishing the management range from other management ranges from the wireless access point device to the wireless communication devices within the management range; At least one or more pieces of information about the different identifiers are added to the data frame in the cooperative transmission and the data frame in the case where the cooperative transmission is not performed, and the data frames are transmitted from the wireless access point device. A wireless communication system comprising:

10. The management frame is a frame that is periodically transmitted for each management range, At least one data frame for the cooperative transmission and at least one data frame for the case where the cooperative transmission is not performed are transmitted within a period of the management frame.

10. The wireless communication system according to claim 9.

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