Communication control device and communication control method

Abstract

To provide a communication apparatus that achieves data sharing and coordinate transmission of shared data.SOLUTION: A communication apparatus that operates as an access point includes: a communicating unit configured to transmit and receive wireless signals; and a control unit configured to control communication operations in the communicating unit, the communication operations including a communication operation for sharing data to be simultaneously transmitted to a single communication terminal between adjacent access points and a communication operation for recognizing that sharing of the data has been completed. The control unit is configured to perform control, when transmitting the shared data simultaneously with the adjacent access points, to multiplex the shared data with a transmission stream addressed to another communication apparatus and transmit the shared data as a multi-user multiplexed stream.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technology disclosed in this specification relates to a communication apparatus and a communication method for transmitting and receiving wireless signals.

Background Art

[0002] A technique for spatially multiplexing and wirelessly transmitting a plurality of data by the Multiple Input Multiple Output (MIMO) method has already been put into practical use. By using this MIMO technology, for example, data can be simultaneously transmitted from one source communication apparatus operating as an access point to a plurality of destination communication apparatuses operating as communication terminals. Specifically, when the access point is equipped with a plurality of antenna modules and the communication terminal is composed of one antenna module, the downlink transmission rate can be increased by using the downlink MIMO technology.

[0003] On the other hand, a technique for communicating while avoiding interference between adjacent access points by operating a plurality of access points in cooperation is also being put into practical use. Recently, a multi-point cooperative transmission technique has been developed in which data is simultaneously transmitted from a plurality of access points to one destination communication apparatus and the data successfully received at the destination is acquired.

[0004] For example, in a system in which access points are connected via a wired LAN (Local Area Network) such as Ethernet (registered trademark) or other communication means and are synchronized in advance, a method in which the access points cooperate to perform data transmission can be considered. In addition, a proposal has been made for a wireless communication apparatus that aggregates a plurality of groups and performs scheduled access in each group (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] An object of the technology disclosed in this specification is to provide a communication device and a communication method that can suitably realize data sharing and cooperative transmission of shared data. MEANS FOR SOLVING THE PROBLEMS

[0007] A first aspect of the technology disclosed in this specification is a communication unit that transmits and receives radio signals, a control unit that controls communication operations in the communication unit, including communication operations for sharing data to be simultaneously transmitted to one communication terminal between adjacent access points and communication operations for recognizing that the sharing of the data has been completed, and a communication device that operates as an access point, comprising these.

[0008] The communication unit can transmit and receive a radio signal configured by multiplexing a plurality of data as multiple streams. When transmitting the shared data simultaneously with the adjacent access points, the control unit controls to multiplex with a transmission stream addressed to another communication device and transmit as a multi-user multiple stream. Further, the control unit controls to multiplex and communicate the data shared between the adjacent access points as multiple streams.

[0009] Also, a second aspect of the technology disclosed in this specification is a step of sharing data to be simultaneously transmitted to one communication terminal between adjacent access points, a step of recognizing that the sharing of the data has been completed, and a step of transmitting the shared data, which is a communication method in an access point, having these.

[0010] Also, a third aspect of the technology disclosed in this specification is a communication unit that transmits and receives wireless signals, a control unit that controls the communication operation in the communication unit, including an operation of recognizing that the same data is transmitted simultaneously from a plurality of access points based on receiving a predetermined frame from an access point, A communication device that operates as a communication terminal connected to an access point, comprising:

[0011] The predetermined frame is a grant frame including information regarding sharing of the same data between adjacent access points. The grant frame includes at least one of information regarding the communication terminal, information regarding the number of multiple transmissions when transmitting the shared data, and communication parameters when transmitting the shared data.

[0012] Also, a fourth aspect of the technology disclosed in this specification is receiving a predetermined frame from an access point; recognizing that the same data is transmitted simultaneously from a plurality of access points based on the received predetermined frame; receiving the same data transmitted simultaneously from the plurality of access points; A communication method in a communication terminal connected to an access point, comprising:

Advantages of the Invention

[0013] According to the technology disclosed in this specification, it is possible to provide a communication device and a communication method capable of sharing data between access points in a short time and efficiently using a wireless transmission path by cooperative transmission of shared data.

[0014] Note that the effects described in this specification are merely examples, and the effects of the present invention are not limited thereto. Also, the present invention may have additional effects other than the above effects.

[0015] Other objects, features, and advantages of the technology disclosed in this specification will become apparent from the more detailed description based on the embodiments described below and the accompanying drawings.

Brief Description of the Drawings

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[0017] Hereinafter, embodiments of the technology disclosed in this specification will be described in detail with reference to the drawings.

[0018] This specification proposes a technique for optimizing data sharing and cooperative transmission among multiple access points. Specifically, data for cooperative transmission between adjacent access points is pre-shared, and a communication device to be the target of cooperative transmission is designated in a Grant frame notifying that the sharing has been successful, and by notifying in advance that cooperative transmission will be carried out at a later timing, a technique for optimizing data sharing and cooperative transmission is proposed.

[0019] In addition, this specification also proposes a technique for efficiently using a wireless transmission path by multiplexing data not only for communicating with one communication device but also data addressed to other communication devices using multi-user spatial division multiplexing technology when an access point performs cooperative transmission.

[0020] In addition, this specification also proposes a technique for sharing data between access points in a short time using single-user spatial division multiplexing technology and synchronizing and transmitting the data at a predetermined timing after sharing.

[0021] FIG. 1 shows a configuration example of a wireless network to which the technique disclosed in this specification is applied. The illustrated wireless network is composed of a first network group and a second network group.

[0022] The first network group is composed of an access point AP1 and communication terminals STA1 and STA3 connected to AP1. In addition, the second network group is composed of an access point AP2 and a communication terminal STA2 connected to AP2. In FIG. 1, the ranges of the respective network groups are each surrounded by a dotted line. Also, the transmission signals of each access point AP1 and AP2 are indicated by solid arrows.

[0023] Here, it is assumed that the access points AP1 and AP2 of each network group are located in positions where they can communicate with each other. Also, it is assumed that the communication terminal STA3 within the first network group is in a state where it is located in a position where it can communicate with the access point AP2 and the communication terminal STA2 of the second network group.

[0024] Also, in the wireless network shown in FIG. 1, it is assumed that interference waves from interference sources such as other communication systems (Other) reach each of the communication terminal STA3 within the first network group and the communication terminal STA2 within the second network group. In FIG. 1, the interference signal is indicated by a dotted arrow.

[0025] Since STA3 can communicate with both AP1 and AP2, it is possible to receive the same data from a plurality of access points AP1 and AP2. Therefore, if data is shared between AP1 and AP2, AP1 and AP2 can transmit the same data simultaneously. Then, STA3 can receive the data more reliably by receiving this simultaneously transmitted data.

[0026] Note that between the access points AP1 and AP2, data sharing may be performed via wired communication such as Ethernet (registered trademark) instead of wireless communication.

[0027] FIG. 2 shows another configuration example of the wireless network to which the technology disclosed in this specification is applied. The illustrated wireless network is composed of a first network group and a second network group.

[0028] The first network group is composed of the access point AP1, and communication terminals STA1 and STA3 connected to AP1. Also, the second network group is composed of the access point AP2 and the communication terminal STA2 connected to AP2. The wireless network shown in FIG. 2 is assumed to further have a master access point (M-AP) that oversees both network groups, and there is another communication system that serves as an interference source. It is assumed that interference waves from the interference source reach each of the communication terminal STA3 within the first network group and the communication terminal STA2 within the second network group. In FIG. 2, the ranges of the respective network groups are each surrounded by a dotted line. Also, the transmission signals of each access point AP1 and AP2 are indicated by solid arrows, and the interference signals are indicated by dotted arrows.

[0029] Since the M-AP can communicate with both AP1 and AP2, it is possible to share data. Specifically, the M-AP can transmit the received data to AP1 and AP2 at high speed and cooperate to deliver the data to STA3 from both AP1 and AP2. Then, STA3 can receive the data more reliably by receiving the data transmitted simultaneously from AP1 and AP2.

[0030] Note that data sharing between the access point M-AP and AP1 and AP2 may be implemented via a wired communication such as Ethernet (registered trademark) instead of wireless communication.

[0031] FIG. 3 shows the process of implementing data sharing and cooperative transmission of data among a plurality of access points. However, assuming the wireless network configuration shown in FIG. 1, the horizontal axis is the time axis. The squares drawn with solid lines on each horizontal axis represent the signals (or frames) transmitted by the corresponding communication device in the corresponding time interval. Also, the squares drawn with dotted lines represent the signals (or frames) received by the corresponding communication device in the corresponding time interval.

[0032] Here, it is assumed that access point AP1 actively performs cooperative transmission, and AP2 passively performs cooperative transmission. Also, communication terminals STA1 and STA3 operate belonging to the first network group operated by AP1, and communication terminal STA2 operates belonging to the second network group operated by AP2.

[0033] In addition, interference signals from interference sources (Other) such as other communication systems reach STA2 and STA3. STA2 and STA3 can recognize the period during which the interference signal is received as the BUSY state. Therefore, each access point AP1 and AP2 can recognize that communication with STA2 and STA3 is impossible because there is no response during the period when the interference signal (BUSY) is received from the interference source (Other).

[0034] Under such circumstances, access point AP1 starts the initiation (Ini) of data sharing for cooperative transmission to subordinate communication terminal STA3 and designates the target access point AP2.

[0035] The initiation of data sharing is started by the access point that actively performs cooperative transmission as needed. In the example shown in Figure 3, AP1 starts the initiation. The initiation may be started at the timing immediately after notification is performed between the two access points AP1 and AP2 in advance, or at the timing immediately before cooperative transmission is performed. Alternatively, the initiation may be transmitted together with the shared data when performing cooperative transmission.

[0036] Due to the initiation, access point AP2 that passively performs cooperative transmission receives the data to be shared hereafter in response to the request from access point AP1 that actively performs cooperative transmission. For example, using the SU (Single User)-MIMO spatial division multiplexing communication technology or the frequency channel bonding technology, the data for cooperative transmission is transmitted from AP1 to AP2, and the data (DMU-3) addressed to STA3 is shared between AP1 and AP2 in a short time.

[0037] Here, it should be noted that communication processing for sharing data (DMU-3) addressed to STA3 between AP1 and AP2 can be performed using the BUSY state in which STA2 and STA3 are affected by interference signals from an interference source (Other). Also, in the communication of shared data (DMU-3) from AP1 to AP2, by using a high-speed transmissible MCS (Modulation and Coding Scheme), data sharing between access points can be realized in a short time.

[0038] When AP2 receives shared data from AP1, it returns an acknowledgment of receipt and a grant frame designating STA3 as the target to receive cooperative transmission to AP1.

[0039] The grant frame transmitted from AP2 reaches not only AP1 but also STA2 and STA3. The frame interval between the grant frame and a data frame (described later) for cooperative transmission of shared data is constant. Therefore, STA2 and STA3 that can receive the grant frame can ensure time synchronization with access points AP1 and AP2, and can recognize that cooperative transmission by surrounding access points will be performed within a predetermined time.

[0040] Then, AP1 transmits a trigger frame describing various parameters of cooperative transmission to its subordinate communication terminals STA1 and STA3 and to AP2 that passively performs cooperative transmission. After that, AP1 and AP2 synchronize their timings and simultaneously perform cooperative transmission of the shared data.

[0041] The trigger frame transmitted from AP1 reaches not only AP2 but also STA1 and STA3. The frame interval between the trigger frame and the immediately subsequent data frame is constant. Therefore, AP2, STA1, and STA3 that can receive the trigger frame can ensure detailed (in microseconds) time synchronization with access point AP1.

[0042] Here, the data transmitted from each access point AP1 and AP2 may also be further space-division multiplexed at each access point. In the example shown in FIG. 3, from the AP1 side, the data (CDMU-3) for STA3 shared with AP2 and the data (CDMU-1) for STA1 under the control of AP1 are multiplexed and transmitted using the space multiplexing technique. Also, from the AP2 side, the data (CDMU-3) for STA3 shared with AP1 and the data (CDMU-2) for STA2 under the control of AP2 are multiplexed and transmitted using the space multiplexing technique. In this way, by the access point space multiplexing and transmitting the data to be cooperatively transmitted with the data addressed to other communication terminals, the radio transmission path can be efficiently utilized.

[0043] Note that when the access point space multiplexes and transmits the data to be cooperatively transmitted with the data addressed to other communication terminals, it is configured to transmit after aligning the time lengths of each transmitted data, and padding (P) is applied to the transmitted data with the shorter time length.

[0044] In the example shown in FIG. 3, AP1 applies padding (P) to the data (CDMU-1) for STA1, which is shorter than the data (CDMU-3) to be cooperatively transmitted to STA3, aligns the time length of CDMU-3, and then transmits. Also, AP2 applies padding (P) to the data (CDMU-2) for STA2, which is shorter than the data (CDMU-3) to be cooperatively transmitted to STA3, aligns the time length of CDMU-3, and then transmits.

[0045] The data that AP1 and AP2 space-division multiplex and cooperatively transmit are received by STA1, STA2, and STA3. Then, STA1, STA2, and STA3 each collect the data addressed to themselves and return their respective reception confirmations in the form of block ACK (BA). Note that at STA3, as long as either one of the CDMU-3 sent from AP1 and the CDMU-3 sent from AP2 is received without error, it is considered that the reception confirmation has been made.

[0046] Block ACK requests (BARs) are sent at different timings for each access point, and each communication terminal returns a block ACK at a different timing for each access point. In the example shown in FIG. 3, a block ACK request is sent from AP1 at the first timing, and ACK frames to AP1 are returned from STA1 and STA3. Also, a block ACK request is sent from AP2 at the second timing, and ACK frames to AP2 are returned from STA2 and STA3.

[0047] These ACK frames may be returned by applying uplink multi-user MIMO technology, or may be returned as response frames to a predetermined trigger frame.

[0048] If AP1 has received all the ACK frames returned from each of STA1 and STA3, it discards all the transmission data CDMU-1 and CDMU-3 stored in the transmission buffer. That is, even if either CDMU-3 transmitted from AP1 or AP2 has not arrived correctly, it is considered that STA3 has received it. Also, if AP1 has an ACK frame that it cannot receive, it starts retransmitting the corresponding data. Similarly, if AP2 has received all the ACK frames returned from each of STA2 and STA3, it discards all the transmission data CDMU-2 and CDMU-3 stored in the transmission buffer. Also, if AP2 has an ACK frame that it cannot receive, it starts retransmitting the corresponding data.

[0049] FIG. 4 shows the flow of data sharing and cooperative transmission of data among a plurality of access points. However, assuming the wireless network configuration shown in FIG. 2, the horizontal axis is the time axis. The squares drawn on each horizontal axis represent the signals (or frames) transmitted by the corresponding communication device in the corresponding time interval. Also, the squares drawn with dotted lines represent the signals (or frames) received by the corresponding communication device in the corresponding time interval.

[0050] Here, there is a master access point (M-AP) that manages cooperative transmission, and the access points AP1 and AP2 of each network group passively perform cooperative transmission under the management of the M-AP. Also, communication terminals STA1 and STA3 operate belonging to the first network group operated by AP1, and communication terminal STA2 operates belonging to the second network group operated by AP2.

[0051] In addition, interference signals from interference sources (Other) such as other communication systems reach STA2 and STA3. STA2 and STA3 can recognize the period during which the interference signal arrives as the BUSY state. Therefore, each access point AP1, AP2 can recognize that communication with STA2 or STA3 is not possible during the period when a signal is arriving from the interference source (Other).

[0052] Under such circumstances, the master AP starts an initiation (Ini) for data sharing for cooperative transmission and designates the target access points AP1 and AP2.

[0053] The initiation of data sharing is started by the access point that manages cooperative transmission as needed. In the example shown in FIG. 4, the master AP starts the initiation. The initiation may be started at the timing immediately after notification is performed between the two access points in advance, or at the timing immediately before cooperative transmission is performed. Alternatively, the initiation may be transmitted together with the shared data when performing cooperative transmission.

[0054] Through initialization, each access point AP1 and AP2 that passively perform cooperative transmission respond to a request from the master AP that manages the cooperative transmission, and thereafter receive data to be shared. For example, data addressed to each communication terminal STA1, STA2, and STA3 is transmitted from the master AP. For example, using SU-MIMO spatial division multiplexing communication technology and frequency channel bonding technology, data for cooperative transmission is transmitted from the master AP to AP1 and AP2, and the data (DMU-3) addressed to STA3 is shared between AP1 and AP2 in a short time. Also, data (DMU-1) addressed to STA1 is transmitted from the master AP to AP1, and data (DMU-2) addressed to STA2 is transmitted from the master AP to AP2. Then, these data will be transmitted from AP1 and AP2 to each communication terminal STA1, STA2, and STA3 by applying MU-MIMO technology (described later).

[0055] Here, it should be noted that communication processing for sharing the data (DMU-3) addressed to STA3 can be performed between the master AP and AP1 and AP2 by using the BUSY state in which STA2 and STA3 are affected by interference signals from an interference source (Other). Also, in the communication of the shared data (DMU-3) from the master AP to AP1 and AP2, data sharing between access points can be realized in a short time by using an MCS capable of high-speed transmission.

[0056] When AP1 and AP2 receive the shared data from the master AP, they each return an acknowledgment of receipt and a grant frame targeted at STA3 to which cooperative transmission is to be received, to the master AP. Here, although AP1 and AP2 are returning the grant frames simultaneously, it is configured to be transmitted using uplink multi-user MIMO spatial division multiplexing or the like.

[0057] The grant frame transmitted from AP1 reaches not only the master AP but also AP2, STA1, and STA3. The grant frame transmitted from AP2 reaches not only the master AP but also AP1, STA2, and STA3. The frame interval between the grant frame and the data frame (described later) that cooperatively transmits shared data is constant. Therefore, STA2 and STA3 that can receive the grant frame can ensure time synchronization with the master AP, AP1, and AP2, and can recognize that cooperative transmission by surrounding access points will be performed within a predetermined time.

[0058] Then, the master AP transmits a trigger frame describing various parameters of cooperative transmission to AP1 and AP2. Thereafter, AP1 and AP2 synchronize their timings and cooperatively transmit the shared data simultaneously. The frame interval between the trigger frame and the immediately subsequent data frame is constant. Therefore, AP1 and AP2 that can receive the trigger frame can ensure detailed (in microseconds) time synchronization with the master AP.

[0059] Here, the data transmitted from each access point AP1 and AP2 may also be space-division multiplexed at each access point. In the example shown in FIG. 4, the data transmitted from AP1 is multiplexed and transmitted as data for STA1 (CDMU-1) and data for STA3 (CDMU-3). Also, the data transmitted from AP2 is multiplexed and transmitted as data for STA2 (CDMU-2) and data for STA3 (CDMU-3). In this way, by space-division multiplexing the data to be cooperatively transmitted with the data for other communication terminals at the access point, the wireless transmission path can be utilized efficiently.

[0060] When an access point space-division multiplexes and cooperatively transmits data addressed to other communication terminals, it is configured to transmit after aligning the time lengths of each transmitted data, and padding (P) is applied to the transmitted data with the shorter time length. In the example shown in FIG. 4, AP1 applies padding (P) to the data (CDMU-1) addressed to STA1, which is shorter than the data (CDMU-3) cooperatively transmitted to STA3, aligns the time length of CDMU-3, and then transmits it. Also, AP2 applies padding (P) to the data (CDMU-2) addressed to STA2, which is shorter than the data (CDMU-3) cooperatively transmitted to STA3, aligns the time length of CDMU-3, and then transmits it.

[0061] The data cooperatively transmitted by AP1 and AP2 through space-division multiplexing respectively are received by STA1, STA2, and STA3. Then, STA1, STA2, and STA3 each collect their own addressed data and return their respective reception confirmations in the form of block ACK (BA). Note that in STA3, as long as it can correctly receive either the CDMU-3 sent from AP1 or the CDMU-3 sent from AP2, it is considered to have received the data correctly.

[0062] Block ACK requests (BAR) are transmitted at different timings for each access point, and each communication terminal returns block ACKs at different timings for each access point. That is, even if either the CDMU-3 transmitted from AP1 or AP2 is not received correctly, it is considered received at STA3. In the example shown in FIG. 4, a block ACK request is transmitted from AP1 at the first timing, and ACK frames to AP1 are returned from STA1 and STA3. Also, a block ACK request is transmitted from AP2 at the second timing, and ACK frames to AP2 are returned from STA2 and STA3.

[0063] These ACK frames may be returned by applying uplink multi-user MIMO technology, or may be returned as response frames to a predetermined trigger frame.

[0064] If AP1 can receive all the ACK frames returned from each of STA1 and STA3, it discards all the transmission data CDMU-1 and CDMU-3 stored in the transmission buffer. Also, if there is an ACK frame that AP1 cannot receive, it starts retransmitting the corresponding data. Similarly, if AP2 can receive all the ACK frames returned from each of STA2 and STA3, it discards all the transmission data CDMU-2 and CDMU-3 stored in the transmission buffer. Also, if there is an ACK frame that AP2 cannot receive, it starts retransmitting the corresponding data.

[0065] Although omitted in FIGS. 2 and 4, it is also assumed that M-AP operates a wireless network and there are one or more communication terminals under its jurisdiction, and similar to AP1 and AP2, it space-division multiplexes data to be cooperatively transmitted with data addressed to other communication terminals.

[0066] FIG. 5 shows an example of a communication sequence for performing an operation check to realize cooperative transmission of data by a plurality of access points.

[0067] However, in FIG. 5, it is assumed that, like the wireless network shown in FIG. 1, the access point AP1 that actively performs cooperative transmission, the access point AP2 that passively performs cooperative transmission, the communication terminals STA1 and STA3 belonging to the network of AP1, and the communication terminal STA2 belonging to the network of AP2 are each operating.

[0068] First, STA1 transmits an Association Request to AP1 (SEQ501). Then, if AP1 permits the association of STA1 to its own network, it returns an Association Response to STA1 (SEQ502).

[0069] Similarly, STA2 sends an association request to AP2 (SEQ503). Then, if AP2 permits the association of STA2 to its own network, it returns an association response to STA2 (SEQ504).

[0070] Furthermore, STA3 sends an association request to AP1 (SEQ505). Then, if AP1 permits the association of STA3 to its own network, it returns an association response to STA3 (SEQ506).

[0071] Here, when each communication terminal STA1, STA2, and STA3 performs the above-described association procedure with access point AP1 or AP2, information exchange including a Coordinate Transmit Information Element describing its own receivable spatial division multiplexing parameters is performed. This Coordinate Transmit Information Element includes the transmission multiplexing number and the reception multiplexing number of the communication device (described later). Therefore, AP1 can grasp the number of spatial multiplexing streams that its subordinate STA1 and STA3 can respectively receive. Similarly, AP2 can grasp the number of spatial multiplexing streams that its subordinate STA2 can receive.

[0072] Furthermore, when AP1 and AP2 grasp that they are, for example, in a position where they can communicate with each other, by exchanging a Coordinate Request and a Coordinate Response composed of Coordinate Transmit Information Elements (SEQ507, SEQ508), they grasp that it is possible to perform coordinated transmission of communication to communication terminals whose existence is grasped at both access points. Also, AP1 can grasp the number of spatial multiplexing streams in the wireless network of AP2, and AP2 can grasp the number of spatial multiplexing streams that STA1 and STA3 can receive in the wireless network of AP1.

[0073] FIG. 6 shows another example of a communication sequence for performing an operation check to realize cooperative transmission of data by a plurality of access points.

[0074] However, in FIG. 6, it is assumed that, like the wireless network shown in FIG. 2, a master AP access point (M-AP) that manages cooperative transmission, access points AP1 and AP2 that passively perform cooperative transmission, communication terminals STA1 and STA3 belonging to the network of AP1, and a communication terminal STA2 belonging to the network of AP2 are each operating.

[0075] First, a station STA1 transmits an association request to an access point AP1 (SEQ601). Then, if AP1 permits the association of STA1 to its own network, AP1 returns an association response to STA1 (SEQ602). Similarly, a station STA2 transmits an association request to an access point AP2 (SEQ603). Then, if AP2 permits the association of STA2 to its own network, AP2 returns an association response to STA2 (SEQ604). Further, a station STA3 transmits an association request to an access point AP1 (SEQ605). Then, if AP1 permits the association of STA3 to its own network, AP1 returns an association response to STA3 (SEQ606).

[0076] Here, when each of the communication terminals STA1, STA2, and STA3 performs the above-described association procedure with the access point AP1 or AP2, information exchange including a cooperative transmission information element in which its own receivable space division multiplexing parameters are described is performed. Therefore, AP1 can grasp the number of spatial multiplexing streams that can be received by the subordinate STA1 and STA3, respectively. Similarly, AP2 can grasp the number of spatial multiplexing streams that can be received by the subordinate STA2.

[0077] Furthermore, when M-AP determines that AP1s are in positions where they can communicate with each other, M-AP exchanges a Coordinate Request and a Coordinate Response, which are composed of coordinated transmission information elements (SEQ607, SEQ608). Also, when M-AP determines that AP2s are in positions where they can communicate with each other, M-AP exchanges a Coordinate Request and a Coordinate Response, which are composed of coordinated transmission information elements (SEQ609, SEQ610). Thereby, M-AP determines that it is possible to perform coordinated transmission of communication to a communication terminal that can be detected at both access points of AP1 and AP2. Also, M-AP can determine the number of spatial multiplexing streams in each of the wireless networks of AP1 and AP2.

[0078] FIG. 7 shows a configuration example of an association frame. Here, the association frame mentioned herein includes both an association request frame and an association response frame. Also, fields that are particularly characteristic in this embodiment are filled in gray.

[0079] The illustrated association frame follows a PLCP (Physical Layer Convergence Protocol) header as a preamble in a predetermined PHY layer and is configured as a management frame in the MAC (Media Access Control) layer. That is, as a conventional association frame structure, it includes fields such as Frame Control indicating the type of the frame, Duration indicating the duration of the frame, Receive Address indicating the destination address, and Transmit Address indicating the source address. And following these conventional fields, a Coordinate Transmit Information Element is included, and a Frame Check Sequence (FCS) calculated according to a predetermined calculation procedure from the entire frame is added at the end. The structure of the Coordinate Transmit Information Element will be left for later description (see Figure 8).

[0080] Figure 8 shows a configuration example of a coordination frame. However, the coordination frame mentioned here includes both a coordination request frame and a coordination response frame. Also, the fields that are particularly characteristic in this embodiment are filled in gray.

[0081] The illustrated coordination frame follows a PLCP header as a preamble in a predetermined PHY layer and is configured as a management frame in the MAC layer. That is, it includes fields such as Frame Control indicating the type of the frame, Duration indicating the duration of the frame, Receive Address indicating the destination address, and Transmit Address indicating the source address. And following these fields, an AP Attribute indicating the attributes of the access point and a Coordinate Transmit Information Element are included, and a Frame Check Sequence (FCS) is added at the end.

[0082] The coordinated transmission information element includes parameters such as Element Type indicating the format of the information element, Length indicating the information length, Available MCS indicating the available modulation and coding schemes, Timing Parameter indicating the parameters of the transmission timing, and A-MPDU (Aggregation MPDU) Counts indicating the number of MPDUs (MAC Protocol Data Init) to be aggregated.

[0083] In addition, the coordinated transmission information element further includes parameters such as Tx MIMO for the transmission multiplexing number and Rx MIMO for the reception multiplexing number as spatial division parameters.

[0084] In addition, the coordinated transmission information element further includes parameters such as Bands indicating the available bandwidth and Channels indicating the available number of channels as frequency parameters.

[0085] Note that various parameters other than those shown in FIG. 8 may be set in the coordinated transmission information element within the coordination frame as required.

[0086] FIG. 9 shows a configuration example of the initiate frame. However, the fields that are particularly characteristic in this embodiment are filled in gray. The initiate frame is used when an access point that actively performs coordinated transmission or a master access point that manages coordinated transmission initiates data sharing for coordinated transmission to a communication terminal (see, for example, FIGS. 3 and 4).

[0087] The illustrated initiate frame follows the PLCP header as a preamble in a predetermined PHY layer and is configured as a control frame in the MAC layer. That is, as a conventional control frame structure, it includes fields such as Frame Control indicating the type of the frame, Duration indicating the duration of the frame, Target AP Address1 indicating the address of the target access point, AP MAC Address indicating the address of the source access point, and optionally further includes Targer Ap Address2 indicating the address of the second target access point.

[0088] The target access point mentioned here is the access point designated by the access point that actively performs cooperative transmission or the master access point that manages cooperative transmission as the partner for cooperative transmission. The target access point is basically an access point that passively performs cooperative transmission. The second target access point is, for example, the target access point secondarily designated by the master access point. Stated according to the examples shown in FIGS. 2 and 4, it is assumed that the M-AP designates AP1 as the first target access point and AP2 as the second target access point. When cooperative transmission is performed using three or more access points, the initiate frame will be provided with a field for storing Targer AP Address3, … indicating the address of the third target access point.

[0089] Subsequent to these fields, parameters such as Coorinate Tx Timing indicating the timing of cooperative transmission, Coordinate MCS Info indicating the modulation method and coding rate during cooperative transmission, and Coordinate Channels indicating the channels for cooperative transmission are further included, and a frame check sequence (FCS) is added at the end.

[0090] FIG. 10 shows a configuration example of a grant frame. However, the fields that are particularly characteristic in this embodiment are filled in gray. The grant frame is used by an access point that passively performs cooperative transmission when receiving confirmation of shared data (see, for example, FIGS. 3 and 4).

[0091] The illustrated grant frame is configured as a control frame in the MAC layer following a PLCP header as a preamble in a predetermined PHY layer. That is, as a conventional control frame structure, it includes fields such as Frame Control indicating the type of the frame, Duration indicating the duration of the frame, Receive Address indicating the destination address, and Transmit Address indicating the source address. Then, following these fields, in addition to Target Address indicating a communication terminal to be the target of cooperative transmission, Coordinate Multiplex indicating the number of cooperative multiplex transmissions, and Coordinate Parameter indicating parameters in the case of cooperative transmission, parameters such as BA Control and BA Information, which are block ACK information of the frame received as shared data, are further included, and a frame check sequence (FCS) is added at the end. Various communication parameters such as the MCS, transmission power, and guard interval length used when performing cooperative transmission are described in Coordinate Parameter.

[0092] It should be understood that by describing information regarding a communication terminal that is the reception target of cooperative transmission in the grant frame and designating a communication terminal that receives cooperative transmission data, it is possible to make the receiving terminal aware in advance that cooperative transmission will be performed on it.

[0093] FIG. 11 shows a configuration example of a trigger frame. However, the fields that are particularly characteristic in this embodiment are filled in gray. The trigger frame is used for an access point that actively performs cooperative transmission or a master access point that manages cooperative transmission to take detailed (in microseconds) timing of cooperative transmission with an access point that passively performs cooperative transmission (see, for example, FIGS. 3 and 4).

[0094] The illustrated trigger frame is configured as a control frame in the MAC layer following a PLCP header as a preamble in a predetermined PHY layer. That is, as a conventional control frame structure, it includes fields such as Frame Control indicating the type of the frame, Duration indicating the duration of the frame, Receive Address indicating the destination address, and Transmit Address indicating the source address. Then, following these fields, Common Information common to all destinations and User Information necessary for each user (for each communication device serving as a destination) are added as needed, and a frame check sequence (FCS) is added at the end.

[0095] As Common Information, bits of Coordinate Transmit indicating that cooperative transmission is to be performed and Coordinate Multiplex indicating that the communication is multiplexed with cooperative transmission are prepared.

[0096] Also, as User Information necessary for each user, Coordinate Parameter, which is the transmission parameter for each user required when performing cooperative transmission, is described. The Coordinate Parameter describes various communication parameters such as the MCS, transmission power, and guard interval length used when performing cooperative transmission.

[0097] FIG. 12 shows the internal structure of a data frame. It is assumed that the illustrated data frame is configured as an A-MPDU frame that aggregates a plurality of sub-frames (MPDUs).

[0098] The preamble of the illustrated data frame is composed of an L (Legacy)-STF (Short Training Field), an L-LTF (Long Training Field), an L-SIG, an RL-SIG (Repeated L-SIG), an HE (High Efficiency)-SIG-A, an HE-SIG-B, an HE-STF, and an HE-LTF group. The STF is used, for example, for rough synchronization acquisition, and the LTF is used, for example, for detailed synchronization acquisition and channel estimation. In addition, each SIG field describes signaling information corresponding to each standard.

[0099] As a parameter of the HE-SIG-A included in the preamble, there is a characteristic in that a Coordinate Transmit bit for identifying that a cooperative transmission operation is being performed is provided. The communication device on the receiving side of the data frame can identify, based on the bit, that the same MPDU is included in other spatially multiplexed A-MPDUs (that is, the same MPDU is being cooperatively transmitted from a plurality of transmission sources).

[0100] In addition, as a parameter of the HE-SIG-B included in the preamble, a Coordinate Parameter in which parameters for performing a cooperative transmission operation are described is included. The Coordinate Parameter describes various communication parameters such as the MCS, transmission power, and guard interval length used during cooperative transmission.

[0101] Also, in the example shown in FIG. 12, eight MPDUs (sub-frames) from MPDU-1 to MPDU-8 are aggregated to form an A-MPDU, and an EOF (End of Frame) padding (Pad) is added as necessary. However, the number of aggregated sub-frames is not limited to eight, and may be seven or less or nine or more.

[0102] Each MPDU configured as a sub-frame of the A-MPDU frame is added with a predetermined delimiter and, if necessary, trailing padding.

[0103] Each individual MPDU is composed of a predetermined MAC header and a data payload, and a frame check sequence (FCS) calculated according to a predetermined calculation procedure for each MPDU is added at the end.

[0104] The MAC header is composed of each field of Frame Control indicating the format of the frame, Duration indicating the duration of the frame, Address1 to Address4 for appropriately specifying the transmitting and receiving devices, Sequence Control storing a sequence number, etc., QoS Control with QoS (Quality of Service) parameters described, and HT (High Throughput) Control with high-speed transmission parameters described.

[0105] FIGS. 13 to 19 each show a configuration example of a data frame applied to data sharing and cooperative transmission. However, in each figure, the horizontal axis is the time axis.

[0106] FIG. 13 shows a configuration example of a frame used when sharing data using a plurality of spatial multiplexing streams among access points. According to the illustrated frame configuration, when sharing data from MPDU-1 to MPDU-4, each MPDU is configured as a different spatial multiplexing stream SD1 to SD4 and multiplexed for transmission, so that sharing can be achieved in a short time.

[0107] For example, in the wireless network configuration shown in FIG. 1, by transmitting the data frame shown in FIG. 13 from AP1 that actively performs cooperative transmission to AP2 that passively performs cooperative transmission, sharing of cooperative transmission data from MPDU-1 to MPDU-4 between AP1 and AP2 can be realized in a short time. Further, by using an MCS capable of high-speed transmission, the required time for data sharing can be further shortened.

[0108] FIG. 14 shows the configuration of data transmitted from the access point AP1 in the wireless network shown in FIG. 1. Here, an example is shown in which data (MPDU-1 to MPDU-4) for performing cooperative transmission to the communication terminal STA3 under the control of AP1 is configured as the first spatial multiplexing stream SD1, and data (MPDU-1 to MPDU-6) for another communication terminal STA1 under the control of AP1 is configured as the second spatial multiplexing stream SD2. When the data lengths are not aligned between the spatial multiplexing streams, padding (Pad) is applied to the shorter spatial multiplexing stream to align the data lengths. In the example shown in FIG. 14, SD2 padding (Pad) is applied. However, the data configuration shown in FIG. 14 is premised on the fact that the number of spatial multiplexing streams that the receiving destination STA1 can receive is 1, and the number of spatial multiplexing streams that STA3 can receive is 2 or more.

[0109] FIG. 15 shows the configuration of data transmitted from the access point AP2 in the wireless network shown in FIG. 1. Here, data (MPDU-1 to MPDU-4) for which AP2 performs cooperative transmission to the communication terminal STA3 belonging to another wireless network is configured as the first spatial multiplexing stream SD3, and data (MPDU-1 to MPDU-8) for another communication terminal STA2 under its control is configured as the second spatial multiplexing stream SD4. When the data lengths are not aligned between the spatial multiplexing streams, padding (Pad) is applied to the shorter spatial multiplexing stream to align the data lengths. In the example shown in FIG. 15, padding (Pad) is applied to SD4. However, the data configuration shown in FIG. 15 is premised on the fact that the number of spatial multiplexing streams that the destination STA2 can receive is 1, and the number of spatial multiplexing streams that STA3 can receive is 2 or more.

[0110] FIG. 16 shows a configuration example of a data frame for transmitting shared data from the master access point (M-AP) to a plurality of access points. Here, in the wireless network shown in FIG. 2, an example is shown in which four spatial multiplexing streams SD1 to SD4 are configured as frames transmitted from the M-AP to each of the access points AP1 and AP2.

[0111] First, data (MPDU-1 to MPDU-4) for which AP1 and AP2 perform cooperative transmission to the communication terminal STA3 is configured as the first spatial multiplexing stream SD1. To this, data (MPDU-1 to MPDU-6) transmitted from AP1 to another communication terminal STA1 is configured as the second spatial multiplexing stream SD2. Also, data (MPDU-1 to MPDU-8) transmitted from AP2 to another communication terminal STA2 is configured as the third spatial multiplexing stream SD3. Further, data (MPDU-1 to MPDU-7) for AP2 is configured as the fourth spatial multiplexing stream SD4. When the data lengths are not aligned between the spatial multiplexing streams, padding (Pad) is applied to the shorter spatial multiplexing stream to align the data lengths. In the example shown in FIG. 16, padding (Pad) is applied to SD2, SD3, and SD4, respectively.

[0112] By transmitting the data frame shown in FIG. 16, it is possible to realize the sharing of data for cooperative transmission from MPDU-1 to MPDU-4 between AP1 and AP2 in a short time, and it is also possible to send the data that AP1 and AP2 respectively send to other communication terminals together. In addition, by using an MCS capable of high-speed transmission, the required time for data sharing can be further shortened.

[0113] FIG. 17 shows another configuration example of a data frame for transmitting shared data from a master access point (M-AP) to a plurality of access points. Here, in the wireless network shown in FIG. 2, an example is shown in which eight spatial multiplexing streams SD1 to SD8 are configured as frames to be transmitted from the M-AP to each of the access points AP1 and AP2.

[0114] First, the data (MPDU-1 to MPDU-4) for which AP1 and AP2 perform cooperative transmission to STA3 is configured as the first spatial multiplexing stream SD1. A part of the data (MPDU-1 to MPDU-4) that AP1 transmits to the communication terminal STA1 is configured as the second spatial multiplexing stream SD2, and the remaining part of the data (MPDU-5 to MPDU-6) that AP1 transmits to STA1 is configured as the third spatial multiplexing stream SD3.

[0115] In addition, a part of the data (MPDU-1 to MPDU-4) that AP2 transmits to another communication terminal STA2 is configured as the fourth spatial multiplexing stream SD4, and the remaining part of the data (MPDU-5 to MPDU-8) that AP2 transmits to STA2 is configured as the fifth spatial multiplexing stream SD5.

[0116] Furthermore, a part of the data (MPDU-1 to MPDU-4) addressed to AP2 is configured as the sixth spatial multiplexing stream SD6, and the remaining part of the data (MPDU-5 to MPDU-7) addressed to AP2 is configured as the seventh spatial multiplexing stream SD7.

[0117] Then, in order to improve the reliability of the data (MPDU-1 to MPDU-4) for which AP1 and AP2 perform cooperative transmission to STA3, the eighth spatial multiplexing stream SD8 is also configured with the same data as SD1.

[0118] By transmitting the data frame shown in FIG. 17, it is possible to realize the sharing of the cooperative transmission data from MPDU-1 to MPDU-4 between AP1 and AP2 in a short time, and the data that AP1 and AP2 transmit to other communication terminals can also be transmitted together. In addition, by using an MCS capable of high-speed transmission, the required time for data sharing can be further shortened.

[0119] FIG. 18 shows a configuration example of a data frame transmitted from the access point AP1 in the wireless network shown in FIG. 2.

[0120] In this figure, the data (MPDU-1 to MPDU-4) for which AP1 performs cooperative transmission to the subordinate communication terminal STA3 is configured as the first spatial multiplexing stream SD1. In addition to this, the data (MPDU-1 to MPDU-6) for the other subordinate communication terminal STA1 is configured as the second spatial multiplexing stream SD2.

[0121] Furthermore, in order to improve the reliability of the data (MPDU-1 to MPDU-4) for which cooperative transmission is performed to STA3, the third spatial multiplexing stream SD3 is configured with the same data as the first spatial multiplexing stream SD1.

[0122] Also, in order to improve the reliability of the data (MPDU-1 to MPDU-6) transmitted to STA1 in a multiplexed manner, the fourth spatial multiplexing stream SD4 is configured with the same data as the second spatial multiplexing stream SD2.

[0123] When the data lengths between spatial multiplexing streams are not aligned, padding (Pad) is applied to the shorter spatial multiplexing stream to align the data lengths. In the example shown in FIG. 18, padding (Pad) is applied to SD2 and SD4 respectively. However, the data configuration shown in FIG. 18 is premised on the fact that the number of spatial multiplexing streams that the destination STA1 can receive is 2 or more, and the number of spatial multiplexing streams that STA3 can receive is 4 or more.

[0124] FIG. 19 shows a configuration example of a data frame transmitted from the access point AP2 in the wireless network shown in FIG. 2.

[0125] In this figure, data (MPDU-1 to MPDU-4) for performing cooperative transmission to the communication terminal STA3 belonging to another wireless network is configured as the first spatial multiplexing stream SD1. In addition to this, data (MPDU-1 to MPDU-8) for the subordinate communication terminal STA2 is configured as the third spatial multiplexing stream SD3.

[0126] Furthermore, in order to improve the reliability of the data (MPDU-1 to MPDU-4) for performing cooperative transmission to STA3, the second spatial multiplexing stream SD2 is configured with the same data as the first spatial multiplexing stream SD1.

[0127] Also, in order to improve the reliability of the data (MPDU-1 to MPDU-8) for multi-transmission to STA2, the fourth spatial multiplexing stream SD4 is configured with the same data as the third spatial multiplexing stream SD3.

[0128] When the data lengths between spatial multiplexing streams are not aligned, padding (Pad) is applied to the shorter spatial multiplexing stream to align the data lengths. In the example shown in FIG. 19, padding (Pad) is applied to SD3 and SD4 respectively. However, the data configuration shown in FIG. 19 is premised on the fact that the number of spatial multiplexing streams that the destination STA2 can receive is 2 or more, and the number of spatial multiplexing streams that STA3 can receive is 4 or more.

[0129] FIG. 20 schematically shows a functional configuration example of a communication device 2000 that can operate as a communication terminal and an access point. The illustrated communication device 2000 includes an Internet connection module 2001, an information input module 2002, a device control unit 2003, an information output module 2004, and a wireless communication module 2005. However, the communication device 2000 may be configured with only the modules necessary for operating as a communication terminal or an access point, and unnecessary modules may be simplified or not incorporated. Alternatively, the communication device 2000 may be configured by further incorporating other functional modules (not shown).

[0130] The Internet connection module 2001 implements functions such as a communication modem for connecting to the Internet network when the communication device 2000 operates as an access point, and realizes an Internet connection via a public communication line and an Internet service provider.

[0131] The information input module 2002 is a functional module for inputting information for conveying an instruction from a user, and is composed of, for example, a push button, a keyboard, a touch panel, etc.

[0132] The device control unit 2003 is a functional module that performs control for operating the communication device 2000 as a communication terminal or an access point as intended by the user.

[0133] The information output module 2004 is a functional module that presents to the user the operating state of the communication device 2000 and information obtained via the Internet. The information output module 2004 is composed of, for example, display elements such as LEDs (Light Emitting Diodes), liquid crystal panels, and organic EL (Electro-Luminescence) displays, and devices such as speakers that output voice and music. The information output module 2004 is configured to display or notify the user of information during or after processing in the device control unit 2003.

[0134] The wireless communication module 2005 is composed of a processor such as a microprocessor and circuits, and is a functional module for processing wireless communication in the communication device 2000. The wireless communication mentioned here includes actively or passively implementing cooperative transmission by an access point, or operating as a master access point that manages cooperative transmission, and includes sharing data between access points and performing cooperative transmission of data to communication terminals. Details of the wireless communication operation will be described later.

[0135] FIG. 21 shows an example of the internal configuration of the wireless communication module 2005 in the communication device 2000 shown in FIG. 20. The illustrated wireless communication module 2005 includes an interface 2101, a transmission buffer 2102, a network management unit 2103, a transmission frame construction unit 2104, a received data construction unit 2105, a reception buffer 2106, a cooperative communication management unit 2107, a spatial multiplexing transmission processing unit 2108, a spatial multiplexing reception processing unit 2109, a management information generation unit 2110, a management information processing unit 2111, a wireless transmission processing unit 2112, a transmission power control unit 2113, a transmission / reception antenna control unit 2114, a detection threshold control unit 2115, and a wireless reception processing unit 2116.

[0136] Here, the interface 2101, the transmission buffer 2102, the network management unit 2103, the transmission frame construction unit 2104, the received data construction unit 2105, and the reception buffer 2106 are configured as parts common to the software in a wireless LAN system based on standards such as IEEE802.11. Also, the wireless transmission processing unit 2112, the transmission power control unit 2113, the transmission / reception antenna control unit 2114, the detection threshold control unit 2115, and the wireless reception processing unit 2116 are configured as parts common to the baseband processing in the wireless LAN system.

[0137] The interface 2101 is a functional module for exchanging inputs from the user, data from the Internet, and information to the user in a predetermined signal format.

[0138] The transmission buffer 2102 is a functional module for temporarily storing inputs from the user or signals to be wirelessly transmitted when received from the interface 2101.

[0139] The network management unit 2103 is a functional module for managing address information of communication devices included in the wireless network. When the communication device 2000 operates as an access point, the network management unit 2103 manages the address information of communication devices (such as communication terminals) connected to its own station. Also, when the communication device 2000 operates as a communication terminal, the network management unit 2103 manages the address information of the access point to be connected.

[0140] In this embodiment, the access point grasps the presence of other access points existing around it and operates in cooperation with those other access points as necessary. Therefore, when the communication device 2000 operates as an access point, the network management unit 2103 is configured to manage information on other access points existing around it as necessary.

[0141] The transmission frame construction unit 2104 is a functional module for constructing wireless transmission data as a data frame for wireless transmission. Also, the transmission frame construction unit 2104 is configured to collect a plurality of MPDUs stored in the transmission buffer 2102 and construct an A-MPDU.

[0142] The received data construction unit 2105 is a functional module for reconstructing original data from a wirelessly received data frame. For example, when an A-MPDU is received, the received data construction unit 2105 removes predetermined header information from the data frame of the A-MPDU, extracts the MPDU, and extracts only the required data portion.

[0143] The reception buffer 2106 is a functional module that temporarily stores the data portions extracted by the received data construction unit 2105 based on the sequence number until all data frames are complete. The reception buffer 2106 is configured to store the received data until the timing arrives to output the data to an application device (not shown) connected via the interface 2101.

[0144] The cooperative communication management unit 2107, when the communication device 2000 operates as an access point, grasps the presence of other access points existing around it, determines whether to perform a cooperative transmission operation with those other access points, and performs parameter settings, etc.

[0145] Specifically, when the communication device 2000 operates as an access point that actively performs cooperative transmission (or a master access point that manages cooperative transmission), the cooperative communication management unit 2107 controls the transmission of an initiate frame (refer to FIG. 9) at the initiation of data sharing for cooperative transmission and the transmission of a trigger frame (refer to FIG. 11) to other access points that passively perform cooperative transmission.

[0146] Also, when the communication device 2000 operates as an access point that passively performs cooperative transmission, the cooperative communication management unit 2107 controls for receiving an initiate frame from another access point and transmitting a grant frame (see FIG. 10) when receiving an acknowledgment of shared data.

[0147] On the other hand, when the communication device 2000 is connected to the wireless network of any access point as a communication terminal, the cooperative communication management unit 2107 performs various settings in the wireless communication module 2005 for receiving data cooperatively transmitted from a plurality of surrounding access points.

[0148] The spatial multiplexing transmission processing unit 2108 is a functional module that performs settings for the number of spatial multiplexing, which is required for simultaneously transmitting a plurality of spatial multiplexing streams, and settings for various parameters required for transmitting the spatial multiplexing streams.

[0149] For example, when the communication device 2000 performs cooperative transmission as an access point, the spatial multiplexing transmission processing unit 2108 performs settings for the spatial multiplexing streams for performing cooperative transmission, and when multiplexing and transmitting data destined for a communication terminal, performs settings for the required parameters each time. Specifically, the spatial multiplexing transmission processing unit 2108 controls to match the timing of cooperative transmission with an adjacent access point and to match the required parameters for transmission.

[0150] The spatial multiplexing reception processing unit 2109 is a functional module that performs settings for the number of spatial multiplexing, which is required for simultaneously receiving a plurality of spatial multiplexing streams, and settings for various parameters required for receiving the spatial multiplexing streams. Specifically, the spatial multiplexing reception processing unit 2109 controls to extract the spatial multiplexing streams that need to be received by itself from the spatial multiplexing frames sent from one or more surrounding access points.

[0151] In a wireless network environment where data sharing and cooperative transmission are performed by a plurality of access points, the spatial multiplexing reception processing unit 2109 is configured to recognize that the same data is being transmitted from different access points and, if necessary, synthesize these received data to construct the received data.

[0152] The management information generation unit 2110 is a functional module that constructs beacon signals necessary for network management, control frames necessary for communication control protocols, and management frames. In this embodiment, when the communication device 2000 operates as an access point, the management information generation unit 2110 generates an initiate frame, a grant frame, a block ACK request frame, etc. On the other hand, when the communication device 2000 operates as a communication terminal, the management information generation unit 2110 generates an ACK frame.

[0153] The management information processing unit 2111 is a functional module that constructs control information necessary for communication control protocols when the received frame is a control frame or a management frame. When the received frame is a beacon frame, the management information processing unit 2111 passes the parameters described in the beacon frame to the cooperative communication management unit 2107 and the network management unit 2103 to grasp the parameters of the access point. Also, when the received frame is an initiate frame or a grant frame, the management information processing unit 2111 notifies the cooperative communication management unit 2107 of the parameters so that subsequent processing can be performed as necessary when the communication device 2000 operates as an access point or as a communication terminal, respectively.

[0154] The wireless transmission processing unit 2112 is a functional module that adds a predetermined preamble to a frame such as a data frame to be wirelessly transmitted at a predetermined frequency channel, converts it into a predetermined baseband signal, and processes it as an analog signal. In FIG. 21, the wireless transmission processing unit 2112 is depicted as a single functional module. However, when dealing with multiple spatial multiplexing streams, a configuration may be adopted in which multiple elements operate in parallel to simultaneously transmit each stream. Alternatively, a configuration may be adopted in which signals of different spatial multiplexing streams are supplied from multiple wireless transmission processing units to the transmission antenna.

[0155] The transmission power control unit 2113 is a functional module that controls the transmission power so that a signal does not reach an unnecessary radio wave coverage range when transmitting a predetermined frame. In the present embodiment, it is assumed that the transmission power control unit 2113 adjusts the minimum necessary transmission power so that a signal reaches the intended received electric field strength on the receiving side, and is configured to control data transmission.

[0156] The transceiver antenna control unit 2114 has a plurality of antenna elements connected thereto, and performs control for wirelessly transmitting a signal as a spatial multiplexing stream and processing for receiving a signal transmitted as these spatial multiplexing streams.

[0157] The detection threshold control unit 2115 is a functional module that, when performing transmission power control, sets a signal detection level such that a signal from a communication device existing within the radio wave coverage range can be detected, and controls to be able to detect a signal at the minimum necessary detection threshold. The detection threshold control unit 2115 is configured to detect a signal at a predetermined detection level or higher if it is the currently used channel.

[0158] When the wireless reception processing unit 2116 detects a predetermined preamble signal, it is a functional module that separates the individually space-division multiplexed streams and performs reception processing on the header and data portions added after the preamble. In FIG. 21, the wireless reception processing unit 2116 is depicted as a single functional module. However, when dealing with multiple space-division multiplexed streams, a configuration where multiple elements operate in parallel to simultaneously receive each stream may also be used.

[0159] When the communication device 2000 is configured as an access point, as can be seen from the configuration within the wireless communication module 2005 shown in FIG. 21, it supports space-division multiplexed transmission. On the other hand, when the communication device 2000 is configured as a communication terminal, it is more preferable but not essential to support space-division multiplexed transmission.

[0160] FIG. 22 shows, in the form of a flowchart, the processing procedure for an access point to register a communication terminal. The illustrated processing procedure is to be carried out in the communication device 2000 operating as an access point.

[0161] When the access point receives an association request frame (see FIG. 7) from an existing (already connected to itself) communication terminal or a new (not connected to itself) communication terminal (Yes in step S2201), it acquires the parameters of that communication terminal (step S2202) and checks whether that communication terminal can receive data cooperatively transmitted from multiple access points based on, for example, the description content of the cooperative transmission information element (step S2203).

[0162] When the communication terminal requesting association supports reception of data transmitted cooperatively (cooperative reception) (Yes in step S2203), the access point registers that communication terminal as a cooperative reception supported terminal (step S2204) and ends this processing.

[0163] On the other hand, if the communication terminal requesting association does not support the reception of data to be cooperatively transmitted (cooperative reception) (No in step S2203), the access point further checks whether the communication terminal supports the reception of spatial multiplexing streams (multiplex reception) (step S2205).

[0164] If the communication terminal requesting association supports the reception of spatial multiplexing streams (Yes in step S2205), the access point registers the communication terminal as a terminal supporting multiplex reception (step S2206) and ends this process. If the communication terminal requesting association does not support the reception of spatial multiplexing streams (No in step S2205), the access point registers the communication terminal as a terminal not supporting multiplex reception (step S2207) and ends this process.

[0165] FIG. 23 shows, in the form of a flowchart, a processing procedure for an access point to register an adjacent access point. The illustrated processing procedure is to be executed in a communication device 2000 operating as an access point (an access point that actively performs cooperative transmission or a master access point that manages cooperative transmission).

[0166] When the access point receives a signal from an overlapping BSS (Basic Service Set) (OBSS signal) (Yes in step S2301), it obtains the operating parameters of the adjacent access point from the received signal (step S2302). As the OBSS signal, for example, an association response frame transmitted by a communication terminal (see FIG. 7) is assumed, and the operating parameters of the adjacent access point can be obtained based on the description content of the cooperative transmission information element and the like.

[0167] Next, the access point checks whether the adjacent access point supports cooperative transmission based on the description content of the cooperative transmission information element and the like (step S2303).

[0168] And, when an adjacent access point supports cooperative transmission (Yes in step S2303), the access point registers the adjacent access point as a cooperative transmission - supported access point (step S2304) and ends this process. Also, when an adjacent access point does not support cooperative transmission (No in step S2303), the access point ends this process without registering such an adjacent access point.

[0169] Note that the above registration process of the cooperative transmission - supported access point may be performed in all access points, but only the access points that actively perform cooperative transmission or the master access points that manage cooperative transmission execute the registration process, and the access points that passively perform cooperative transmission may not perform it.

[0170] FIG. 24 shows, in the form of a flowchart, the processing procedure when an access point receives transmission data. The illustrated processing procedure is assumed to be implemented in the communication device 2000 operating as an access point.

[0171] When the access point receives transmission data via the interface 2001 (Yes in step S2401), it acquires the address information of the communication device that is the destination of the transmission data (step S2402), and further acquires the association information of the communication device (communication terminal) that is the destination (step S2403).

[0172] Next, the access point checks whether spatial multiplexing transmission of the transmission data is possible (step S2404). Whether spatial multiplexing transmission is possible is determined based on whether the access point itself supports spatial multiplexing transmission and whether the destination communication device supports spatial multiplexing transmission. When both support spatial multiplexing transmission, the allowable (maximum) number of spatial multiplexing streams is determined based on the possible number of multiplexing streams of each of the access point itself and the destination communication device.

[0173] And if spatial multiplexing transmission is possible (Yes in step S2404), the access point acquires the connection status with the access points of overlapping basic service sets (OBSSs) (step S2405), and further checks whether cooperative transmission with the OBSS AP is possible (step S2406).

[0174] In step S2406, the case where cooperative transmission can be performed specifically means that the access point itself has the capability to perform cooperative transmission, and there exists an OBSS AP that has already been registered as a cooperative transmission - capable access point according to the processing procedures shown in FIG. 23 and the like.

[0175] Here, if cooperative transmission with the OBSS AP is possible (Yes in step S2406), the access point sets the transmission data received in step S2401 to be capable of spatial multiplexing transmission in cooperation between access points (step S2407). On the other hand, if cooperative transmission with the OBSS AP is not possible (No in step S2406), the access point sets the transmission data to be capable of single - spatial multiplexing transmission (step S2408).

[0176] Also, if spatial multiplexing transmission is not possible (No in step S2404), the access point sets the transmission data received in step S2401 to be capable of transmission as non - spatial - multiplexing - compatible (step S2409).

[0177] Then, the access point stores the data addressed to the communication device whose address information was acquired in step S2402 together with the transmission possibility (whether it is cooperative - transmission - capable, single - spatial - multiplexing - transmission - capable, or single - non - multiplexing - transmission - capable) in the transmission buffer (step S2410), and ends this process.

[0178] FIG. 25 shows, in the form of a flowchart, the processing procedure for an access point to actively perform cooperative transmission. It is assumed that the illustrated processing procedure is carried out in the communication device 2000 operating as an access point.

[0179] When there is data to be transmitted and the transmission timing arrives (Yes in step S2501), the access point checks whether it is possible to perform cooperative transmission (step S2502).

[0180] In step S2501, the case where there is data to be transmitted means, for example, when receiving transmission data according to the processing procedure shown in FIG. 24 and storing it in the transmission buffer 2102. Also, in step S2502, the case where cooperative transmission can be performed specifically means that the access point itself has the capability to perform cooperative transmission and there exists a registered cooperative transmission - corresponding access point according to the processing procedure shown in FIG. 23 and the like.

[0181] If cooperative transmission can be carried out (Yes in step S2502), the access point transmits an initiate frame (see FIG. 9) to the adjacent access point corresponding to the cooperative transmission (step S2503). Subsequently, after transmitting the shared data for cooperative transmission (step S2504), it waits for a grant frame (see FIG. 10) from the access point that is the destination of the initiate frame (step S2505). In step S2503, the adjacent access point corresponding to the cooperative transmission is, for example, an access point registered as a cooperative - transmission - corresponding access point according to the processing procedure shown in FIG. 23. Also, in step S2504, by using an MCS capable of high - speed transmission, data sharing between access points can be realized in a short time.

[0182] Also, when coordinated transmission cannot be performed (No in step S2502), or when a grant frame cannot be received from an adjacent access point supporting coordinated transmission (No in step S2505), the access point checks whether multiplexed data transmission is possible (step S2506).

[0183] In step S2506, whether multiplexed transmission is possible is determined by whether the access point itself supports multiplexed transmission and whether the destination communication device supports multiplexed transmission. When multiplexed transmission is possible for both, it is configured to determine the allowed (maximum) number of multiplexed streams based on the possible number of multiplexed streams of each of the access point itself and the destination communication device.

[0184] Then, when a grant frame is received from the access point that is the destination of the initiate frame and the reception of the shared data can be confirmed (Yes in step S2505), or when a grant frame cannot be received but multiplexed data transmission is possible (Yes in step S2506), the access point further checks whether spatial multiplexed transmission within the access point can be performed (step S2507). Specifically, in step S2507, the access point checks whether there is a communication terminal supporting spatial multiplexed transmission in its own network and whether there is data for that communication terminal.

[0185] When spatial multiplexed transmission within the access point can be performed (Yes in step S2507), the access point acquires other spatial multiplexed data (step S2508). That is, the access point acquires the data for the subordinate communication terminals to be transmitted simultaneously with the coordinated transmission of the shared data by spatial multiplexing.

[0186] Next, the access point transmits a trigger frame for performing downlink multi-user spatial multiplexed transmission (DL MU-MIMO) to the adjacent access point supporting coordinated transmission (step S2509).

[0187] Then, after transmitting the trigger frame, the access point transmits data at a predetermined transmission timing (step S2510). The frame interval between the trigger frame and the spatial multiplexing transmission frame is constant. Therefore, by transmitting the trigger frame in advance, it is possible to ensure time synchronization in units of microseconds among the access points performing cooperative transmission. Also, in step S2510, the access point multiplexes, using spatial multiplexing technology, data addressed to other communication terminals (acquired in step S2508) onto the data to be cooperatively transmitted, thereby enabling efficient utilization of the wireless transmission path.

[0188] Also, when data multiplexing transmission is not possible (No in step S2506), the access point transmits the data as it is at a predetermined transmission timing without transmitting the trigger frame (step S2510).

[0189] After data transmission, the access point transmits a block ACK request frame as necessary (step S2511) and waits for reception of an ACK frame from the data receiving side (step S2512).

[0190] Then, when the ACK frame is received and all of the data has been received normally (Yes in step S2512), the access point discards the transmitted data from the transmission buffer 2101 (step S2513) and ends this process.

[0191] When the access point cooperatively transmits shared data, the communication terminal at the transmission destination returns an ACK if it can receive the data from any of the access points that performed the cooperative transmission. In any case, when the access point receives an ACK from the communication terminal at the cooperative transmission destination of the shared data (Yes in step S2512), it discards the shared data from the transmission buffer 2101 (step S2513) and ends this process.

[0192] On the other hand, if the ACK frame cannot be received and not all of the data has been received (No in step S2512), the process returns to step S2502, and the access point performs retransmission processing of the data.

[0193] FIG. 26 shows, in the form of a flowchart, a processing procedure for an access point to passively perform cooperative transmission. The illustrated processing procedure is to be implemented in the communication device 2000 operating as an access point.

[0194] When an access point that passively performs cooperative transmission receives an initiate frame (see FIG. 9) from an adjacent access point (that actively performs cooperative transmission) (Yes in step S2601), it obtains the parameters related to cooperative transmission described in the frame and performs settings for cooperative transmission (step S2602).

[0195] Also, when the access point receives the shared data for cooperative transmission sent subsequently (Yes in step S2603), it stores this in the transmission buffer 2101 as data for cooperative transmission (step S2604). By transmitting the shared data using a high-speed transmissible MCS from an access point that actively performs cooperative transmission, data sharing between access points can be realized in a short time.

[0196] Next, when the access point confirms that it supports cooperative transmission or approves of performing cooperative transmission (Yes in step S2605), it returns a grant frame (see FIG. 10) to the access point that is the source of the initiate frame (step S2606).

[0197] Next, the access point further checks whether it can perform spatial multiplexing transmission within the access point (step S2607). Specifically, in step S2607, the access point checks whether there is a communication terminal corresponding to spatial multiplexing transmission in its own network and whether there is data addressed to that communication terminal. Also, based on the possible number of multiple streams of each of the access point itself and the receiving communication device, the allowable (maximum) number of multiple streams will be determined.

[0198] And when the access point can perform spatial multiplexing transmission within the access point (Yes in step S6507), the access point acquires other spatial multiplexing data (step S2608). That is, the access point acquires data addressed to subordinate communication terminals that should be transmitted simultaneously with the cooperative transmission of shared data by spatial multiplexing.

[0199] After that, when the timing of cooperative transmission arrives by receiving a trigger frame for performing downlink multi-user spatial multiplexing transmission (step S2609), the access point performs data transmission by cooperative transmission (step S2610). The frame interval between the trigger frame and the spatial multiplexing transmission frame is constant. Therefore, by receiving the trigger frame in advance, time synchronization in microseconds can be ensured among the access points performing cooperative transmission. Also, in step S2610, the access point can efficiently utilize the wireless transmission path by multiplexing data addressed to other communication terminals (acquired in step S2608) onto the data to be cooperatively transmitted using spatial multiplexing technology.

[0200] After data transmission, the access point transmits a block ACK request frame as necessary (step S2611) and waits for reception of an ACK frame from the data receiving side (step S2612).

[0201] And, if an ACK frame is received and all of the data has been successfully received (Yes in step S2612), the access point discards the transmitted data from the transmission buffer 2101 (step S2613) and ends this process.

[0202] When the access point performs cooperative transmission of shared data, if the communication terminal at the destination can receive the data from any of the access points that performed the cooperative transmission, it returns an ACK. In any case, when the access point receives an ACK from the communication terminal that is the cooperative transmission destination of the shared data (Yes in step S2612), it discards the shared data from the transmission buffer 2101 (step S2613) and ends this process.

[0203] On the other hand, if the ACK frame cannot be received and all of the data has not been received (No in step S2612), the process returns to step S2601 and the access point performs retransmission processing of the data.

[0204] FIG. 27 shows, in the form of a flowchart, a processing procedure for a communication terminal to receive cooperative transmission data from a plurality of access points. The illustrated processing procedure is assumed to be implemented in a communication device 2000 operating as a communication terminal under any of the access points.

[0205] When the communication terminal receives a grant frame (see FIG. 10) from surrounding access points (Yes in step S2701) and is specified as a reception target for cooperative transmission data within the grant frame (Yes in step S2702), or when it receives a trigger frame (see FIG. 11) from surrounding access points and is specified as a destination within the trigger frame (Yes in step S2704), it acquires the parameter information described in the received grant frame or trigger frame (step S2705).

[0206] Then, the communication terminal receives and processes the multiplexed data sent at a predetermined timing (step S2706). The multiplexed data includes the cooperative transmission data designated with itself (or another communication terminal) as the target and the data designated with another communication terminal (or itself) as the destination.

[0207] Here, it should be understood that by describing information regarding the communication terminal that is the reception target of cooperative transmission in the grant frame and designating the communication terminal that receives the cooperative transmission data, it is possible to make the target terminal aware in advance that cooperative transmission will be performed.

[0208] Also, the frame intervals of the grant frame, the trigger frame, and the data frame that will be cooperatively transmitted thereafter are constant. Therefore, the communication terminal can ensure time synchronization with the access point that performs cooperative transmission by receiving the grant frame and the trigger frame in advance. In particular, when the immediately preceding trigger frame can be received, time synchronization can be ensured in units of microseconds.

[0209] If the communication terminal can receive the data normally in step S2706 (step S2707), it records the sequence number of the MPDU as ACK information (step S2708).

[0210] Until the communication terminal receives until the end of the frame (aggregation frame) (No in step S2709), it returns to step S2706 and repeatedly receives the aggregated MPDUs.

[0211] Then, after the communication terminal completes receiving until the end of the frame (Yes in step S2709), when it receives a predetermined block ACK request (BAR) designated to respond itself (step S2710), it returns an ACK frame storing the ACK information recorded in step S2708 (step S2711).

[0212] After sending an ACK frame, if all data has been collected (Yes in step S2712), the communication terminal ends this process. On the other hand, if all data has not been received (No in step S2712), the process returns to step S2701 and the communication terminal waits for the data to be resent.

[0213] Finally, the effects and advantages of the technology proposed in this specification for optimizing data sharing and cooperative transmission among multiple access points will be summarized.

[0214] (1) Since multiple access points simultaneously cooperate to transmit the shared transmission data, the destination communication terminal can stably receive the data.

[0215] (2) When sharing data for cooperative transmission between adjacent access points, by configuring multiple data (MPDUs) as spatial multiplexing streams, data sharing can be realized in a short time.

[0216] (3) It is possible to perform communication for data sharing between access points by using the timing when data cannot be transmitted to the communication terminal that is the target of cooperative transmission.

[0217] (4) By describing information about the communication terminal that is the target of cooperative transmission in the grant frame that notifies the reception confirmation of the shared data and designating the communication terminal that receives the cooperative transmission data, the receiving terminal can be made aware in advance that cooperative transmission will be performed for it.

[0218] (5) When performing cooperative transmission by multiple access points, by multiplexing data addressed to other communication terminals as spatial multiplexing streams in the data addressed to the communication terminal that is the target of cooperative transmission, wireless transmission can be efficiently performed.

[0219] (6) When performing cooperative transmission with a plurality of access points, the transmission parameters are selected such that the coding method and modulation method can ensure reception of transmissions from access points with poor connection status. Therefore, although cooperative transmission may occupy the wireless transmission path for a relatively long time, by using this time to multiplex and transmit more data to other communication devices with better connection status, the transmission path utilization efficiency can be improved.

[0220] (7) The access point can efficiently utilize the wireless transmission path by simultaneously performing communication with communication terminals connected to itself and communication with communication terminals connected to other access points using spatial division multiplexing technology.

[0221] (8) By multiplexing and transmitting a plurality of spatial multiplexing streams from one access point to one communication terminal, the data transmission amount per unit time can be increased.

Industrial Applicability

[0222] As described above, the technology disclosed in this specification has been described in detail with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions to the embodiments without departing from the gist of the technology disclosed in this specification.

[0223] The technology disclosed in this specification can be applied to wireless networks based on wireless LAN standards such as IEEE801.11, for example, but is not limited thereto. The technology disclosed in this specification can be similarly applied to various types of wireless systems in which adjacent access points or base stations can cooperate and operate.

[0224] In short, the technology disclosed in this specification has been described in the form of examples, and the description in this specification should not be interpreted restrictively. To determine the gist of the technology disclosed in this specification, the scope of the claims should be considered.

[0225] Incidentally, the technology disclosed in this specification can also be configured as follows.

[0226] (1) A communication unit that transmits and receives wireless signals, A control unit that controls communication operations in the communication unit, including communication operations for sharing data to be transmitted to one communication terminal simultaneously between adjacent access points, and communication operations for recognizing that the sharing of the data has been completed. A communication device operating as an access point, comprising the above.

[0227] The communication unit can transmit and receive a wireless signal configured by multiplexing a plurality of data as multiple streams, When transmitting the shared data simultaneously with the adjacent access point, the control unit controls to multiplex it with a transmission stream addressed to another communication device and transmit it as a multi-user multiple stream. The communication device according to (1) above.

[0228] (2-1) The communication unit can transmit and receive a wireless signal configured by multiplexing a plurality of data as spatial multiple streams, When transmitting the shared data simultaneously with the adjacent access point, the control unit controls to multiplex it with a transmission stream addressed to another communication device and transmit it as a multi-user spatial multiple stream. The communication device according to (1) above.

[0229] (3) The communication unit can transmit and receive a wireless signal configured by multiplexing a plurality of data as multiple streams, The control unit controls to multiplex and communicate the data shared between the adjacent access points as multiple streams. The communication device according to any one of (1) or (2) above.

[0230] (3-1) The communication unit can transmit and receive a wireless signal configured by multiplexing a plurality of data as spatial multiple streams, The control unit controls to multiplex and communicate data shared between the adjacent access points as spatial multiplexing streams. The communication device according to any one of (1) to (3) above.

[0231] (4) The control unit controls to perform a communication operation for sharing the data between the adjacent access points in a time interval during which the one communication terminal is unable to communicate. The communication device according to any one of (1) to (3) above.

[0232] (5) The control unit controls to perform the communication for sharing the data between the adjacent access points by using an encoding method or a modulation method capable of high-speed transmission. The communication device according to any one of (1) to (4) above.

[0233] (6) The control unit notifies the adjacent access points of sharing the data or simultaneously transmitting the shared data to the one communication terminal by transmitting a predetermined initiation frame. The communication device according to any one of (1) to (5) above.

[0234] (7) The control unit recognizes sharing the data or simultaneously transmitting the shared data to the one communication terminal when receiving a predetermined initiation frame from the adjacent access point. The communication device according to any one of (1) to (5) above.

[0235] (8) The initiate frame includes information about the access points that simultaneously transmit the data to be shared. The communication device according to any one of (6) or (7) above.

[0236] (9) The initiate frame further includes at least one of information regarding the transmission timing of the data to be shared, information regarding the coding method or modulation method at the time of transmitting the data to be shared, and information regarding the channel for transmitting the data to be shared. The communication device according to (8) above.

[0237] (10) The control unit controls the transmission timing of the data to be shared based on transmitting a predetermined trigger frame or receiving the trigger frame from the adjacent access point. The communication device according to any one of (1) to (9) above.

[0238] (11) The control unit recognizes the sharing of the data based on communication of a predetermined grant frame with the adjacent access point. The communication device according to any one of (1) to (10) above.

[0239] (12) The control unit controls to return the grant frame to the adjacent access point that has transmitted the data to be shared. The communication device according to (11) above.

[0240] (13) The control unit controls the reception process of the grant frame returned from the adjacent access point that is the reception destination of the data to be shared. The communication device according to (11) above.

[0241] (14) The grant frame includes at least one of information regarding the one communication terminal, information regarding the number of multiplex transmissions when transmitting the data to be shared, and communication parameters at the time of transmitting the data to be shared. The communication device according to any one of (11) to (13) above.

[0242] (15) The communication unit can transmit and receive a radio signal configured by multiplexing a plurality of data as a multiplex stream. The grant frame further includes information regarding the number of multiplexed transmissions when transmitting the data to be shared, and at least one of the communication parameters when transmitting the data to be shared. The communication device according to (13) above.

[0243] (16) Based on the reception of the data to be shared being completed at the one communication terminal, the control unit discards the data to be shared. The communication device according to any one of (1) to (15) above.

[0244] (17) Based on the number of multiplexed streams that can be received by the one communication terminal and the other communication terminal, the control unit controls the multiplexed transmission of data. The communication device according to (2) above.

[0245] (18) A step of sharing data to be simultaneously transmitted to one communication terminal between adjacent access points; A step of recognizing that the sharing of the data is completed; A step of transmitting the shared data; A communication method at an access point, comprising:

[0246] (19) A communication unit for transmitting and receiving radio signals; A control unit for controlling the communication operation in the communication unit, including an operation of recognizing that the same data is simultaneously transmitted from a plurality of access points based on receiving a predetermined frame from an access point; A communication device operating as a communication terminal connected to an access point, comprising:

[0247] (19-1) The predetermined frame is a grant frame including information regarding the sharing of the same data between the adjacent access points. The communication device according to (19) above.

[0248] (19-2) The grant frame includes at least one of information regarding the communication terminal, information regarding the number of multiplexed transmissions when transmitting the data to be shared, and communication parameters at the time of transmitting the data to be shared. The communication device according to the above (19-1).

[0249] (19-3) The communication unit can transmit and receive a wireless signal configured by multiplexing a plurality of data as a multi-stream. The control unit controls the reception of a multi-user multi-stream in which a stream of the same data and a transmission stream addressed to another communication device are multiplexed from the plurality of access points. The communication device according to the above (19).

[0250] (20) A step of receiving a predetermined frame from an access point; A step of recognizing that the same data has been transmitted simultaneously from a plurality of access points based on the received predetermined frame; A step of receiving the same data transmitted simultaneously from the plurality of access points; A communication method in a communication terminal connected to an access point, comprising:

Explanation of Signs

[0251] 2000... Communication device, 2001... Internet connection module 2002... Information input module, 2003... Device control unit 2004... Information output module, 2005... Wireless communication module 2101... Interface, 2102... Transmission buffer 2103... Network management unit, 2104... Transmission frame construction unit 2105... Received data construction unit, 2106... Received buffer 2107... Cooperative communication management unit, 2108... Spatial multiplexing transmission processing unit 2109... Spatial multiplexing reception processing unit, 2110... Management information generation unit 2111... Management information processing unit, 2112... Wireless transmission processing unit 2113… Transmission power control unit, 1014… Transceiver antenna control unit 2115… Detection threshold control unit, 2116… Wireless reception processing unit

Claims

1. A control unit is provided in a third wireless communication device to control a communication unit provided in the third wireless communication device to receive a first signal including data to be wirelessly transmitted simultaneously to a second wireless communication device together with a first wireless communication device. The control unit controls the communication unit to transmit a second signal including information indicating the second wireless communication device in response to receiving the data. A communication control device.

2. The information indicating the second wireless communication device is information indicating an address of the second wireless communication device. The communication control device according to claim 1.

3. The control unit controls the communication unit to receive the first signal from the first wireless communication device and transmit the second signal to the first wireless communication device. The communication control device according to any one of claims 1 to 2.

4. The control unit controls the communication unit to receive the first signal from a fourth wireless communication device and transmit the second signal to the fourth wireless communication device. The communication control device according to any one of claims 1 to 2.

5. The communication unit transmits a wireless signal formed by multiplexing a plurality of data. The second signal includes information regarding the number of multiplex transmissions when transmitting the data and at least one of communication parameters at the time of transmitting the data. The communication control device according to any one of claims 1 to 4.

6. The first signal includes at least one of information regarding the transmission timing of the shared data, information regarding the coding method or modulation method at the time of transmitting the shared data, and information regarding the channel for transmitting the shared data. The communication control device according to any one of claims 1 to 4.

7. The first signal includes information indicating the third wireless communication device that simultaneously transmits the data. The communication control device according to any one of claims 1 to 4.

8. The control unit controls the communication unit to receive a fourth signal including information indicating that cooperative transmission is to be performed. The communication control device according to any one of claims 1 to 7.

9. The information indicating that cooperative transmission is to be performed is common information for a plurality of wireless communication devices that are destinations of the data. The communication control device according to claim 8.

10. The fourth signal includes information indicating that multiplex transmission is to be performed. The communication control device according to claim 8.

11. The fourth signal includes information indicating parameters for cooperative transmission of the data. The communication control device according to any one of claims 8 to 10.

12. The information indicating parameters for cooperative transmission of the data is sent as necessary information for each of a plurality of wireless communication devices. The communication control device according to claim 11.

13. The information indicating the parameters includes at least one of information indicating an MCS, transmission power, and guard interval length used for cooperative transmission of the data. The communication control device according to claim 11.

14. The control unit discards the data based on completion of reception of the data in the second wireless communication device. The communication control device according to any one of claims 1 to 13.

15. The second signal includes information indicating reception confirmation of the data. The communication control device according to any one of claims 1 to 14.

16. The control unit controls multiplexed transmission of the data based on the number of multiplexed streams that can be received by the second wireless communication device. The communication control device according to any one of claims 1 to 15.

17. The first signal is transmitted using an encoding method or modulation method capable of high-speed transmission. The communication control device according to any one of claims 1 to 16.

18. A control step of controlling a communication unit provided in a third wireless communication device to receive a first signal including data to be wirelessly transmitted to a second wireless communication device simultaneously with a first wireless communication device, In the control step, the communication unit is controlled to transmit a second signal including information indicating the second wireless communication device in response to receiving the data. Communication control method.

19. A control unit is provided for controlling a communication unit provided in a predetermined wireless communication device to transmit a first signal including data to be wirelessly transmitted to a second wireless communication device simultaneously with another wireless communication device to a third wireless communication device, The control unit controls the communication unit to receive a second signal including information indicating the second wireless communication device, which is transmitted in response to the third wireless communication device receiving the data. Communication control device.

20. A control step is provided for controlling a communication unit provided in a predetermined wireless communication device to transmit a first signal including data to be wirelessly transmitted to a second wireless communication device simultaneously with another wireless communication device to a third wireless communication device. In the control step, the communication unit is controlled to receive a second signal including information indicating the second wireless communication device, which is transmitted in response to the third wireless communication device receiving the data. Communication control method.

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