communication control device

Abstract

To make it possible to prevent retransmission of data that does not need to be retransmitted.SOLUTION: A communication unit of a Master AP communicates with an AP1 and an AP2. A control unit of the Master AP controls transmission of a Joint Tx Trigger frame, in which a transmitting method of a transmission result of a coordinated transmission by the AP1 and the AP2 to an STA is set, to the AP1 and the AP2. The control unit controls reception of a Joint Tx Response frame indicating the transmission result of the coordinated transmission from at least one of the AP1 and the AP2 on the basis of contents described in the Joint Tx Trigger frame. The control unit controls to determine whether or not to retransmit the coordinated transmission on the basis of the received Joint Tx Response frame. The present technology can be applied to, for example, communication systems.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present technology relates to a communication control device, and more particularly to a communication control device that can prevent retransmission of data that does not need to be retransmitted. [Background technology]

[0002] In recent years, access points (hereafter referred to as APs) have been densely placed not only in public facilities such as stadiums but also in homes. For this reason, technology that enables APs to cooperate with each other and improve system throughput and reliability has attracted attention.

[0003] When APs cooperate with each other, there may be an AP (Master AP) that manages the APs. One of the AP cooperation technologies is Joint Transmission, which allows multiple APs to simultaneously transmit to a single terminal (STA).

[0004] When AP1 and AP2 perform cooperative transmission in response to an instruction from the Master AP, AP1 and AP2 cooperatively transmit data to a STA. Then, the STA that receives the data transmits an ACK, which is an acknowledgment of the data. Patent Document 1 describes a technique for controlling a modulation and coding scheme based on the ACK. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-119232 Summary of the Invention [Problem to be solved by the invention]

[0006] The ACK sent from the STA is received only by AP2. If AP1 fails to receive the ACK, AP1 may attempt to retransmit the data even though the STA has successfully received the data and sent an ACK.

[0007] The present technology has been made in view of such circumstances, and makes it possible to prevent data that does not need to be retransmitted from being retransmitted. [Means for solving the problem]

[0008] A communication control device according to one aspect of the present technology includes a communication unit that communicates with a first wireless communication device and a second wireless communication device, and a control unit that controls the transmission of response setting information to the first wireless communication device and the second wireless communication device, the response setting information setting a method for transmitting a transmission result of a cooperative transmission by the first wireless communication device and the second wireless communication device to a wireless communication terminal, the control unit that controls the reception of a transmission result response signal indicating the transmission result of the cooperative transmission from at least one of the first wireless communication device and the second wireless communication device based on the content described in the response setting information, and the control unit that controls the determination of whether or not to retransmit the cooperative transmission based on the received transmission result response signal.

[0009] In one aspect of the present technology, communication is performed with a first wireless communication device and a second wireless communication device, and the following steps are performed: transmitting response setting information to the first wireless communication device and the second wireless communication device, the response setting information setting a method for transmitting a transmission result of a cooperative transmission to a wireless communication terminal by the first wireless communication device and the second wireless communication device; receiving a transmission result response signal indicating the transmission result of the cooperative transmission from at least one of the first wireless communication device and the second wireless communication device based on the contents described in the response setting information; and determining whether or not to retransmit the cooperative transmission based on the received transmission result response signal. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a configuration example of a communication system according to the present technology. [Figure 2] FIG. 1 is a block diagram illustrating an example of the configuration of a wireless communication device. [Figure 3] FIG. 10 is a diagram showing a sequence of cooperative transmission according to the present technology. [Figure 4] FIG. 10 is a diagram illustrating an example format of a Joint Tx Trigger frame. [Figure 5] FIG. 10 is a diagram illustrating an example format of a Joint Tx Response frame. [Figure 6] FIG. 10 is a diagram showing another sequence of cooperative transmission according to the present technology. [Figure 7] FIG. 10 is a diagram illustrating an example format of a Joint Tx Response Request frame. [Figure 8] FIG. 10 is a diagram illustrating an example format of a Joint Tx End frame. [Figure 9] 10 is a flowchart illustrating a cooperative transmission process of a Master AP. [Figure 10] 10 is a flowchart illustrating a cooperative transmission process of an AP. [Figure 11] FIG. 10 is a diagram illustrating an example of the format of a Joint Tx Response frame in the second embodiment. [Figure 12] FIG. 10 is a diagram showing another sequence of cooperative transmission according to the present technology. [Figure 13] FIG. 1 is a block diagram illustrating an example of the configuration of a computer. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present technology will be described in the following order. 0. System and device configuration examples 1. First embodiment (example of transmission of information related to Block Ack) 2. Second embodiment (example of buffer amount also being transmitted) 3. Third embodiment (example of transmission triggered by STA) 4. Fourth embodiment (computer)

[0012] <0. System and device configuration examples> <Example of communication system configuration> FIG. 1 is a diagram illustrating an example of the configuration of a communication system according to an embodiment of the present technology.

[0013] 1 is configured by access points (hereinafter referred to as AP) 1 and AP 2 and a Master AP connected by wired or wireless communication. The communication system is also configured by AP 1 and AP 2 and a wireless communication terminal STA connected by wireless communication.

[0014] AP1 and AP2 are composed of wireless communication devices 11-1 and 11-2 that cooperate to transmit data to STAs. STAs are composed of wireless communication terminals 12 that belong to a network managed by the APs. The Master AP is composed of a communication control device 13 that controls communication for multiple APs. When there is no need to particularly distinguish between the wireless communication devices 11-1 and 11-2, they will be referred to as wireless communication device 11.

[0015] The number and positional relationship of the wireless communication devices in FIG. 1 are merely an example, and are not limited to the description in FIG.

[0016] <Configuration example of wireless communication device> FIG. 2 is a block diagram showing an example of the configuration of a wireless communication device.

[0017] The wireless communication device 11 shown in FIG. 2 is a device that operates as an AP.

[0018] The wireless communication device 11 is configured with a control unit 31, a power supply unit 32, a communication unit 33, and a memory unit 35. The communication unit 33 may be configured with two or more units. The control unit 31 and the communication unit 33 may be configured as one or more LSIs.

[0019] The communication unit 33 transmits and receives data. The communication unit 33 is configured with a memory unit 50, a data processing unit 51, a wireless control unit 52, a modulation / demodulation unit 53, a signal processing unit 54, a channel estimation unit 55, wireless interface (I / F) units 56-1 to 56-N, and amplifier units 57-1 to 57-N. The communication unit 33 may be an independent component, or some of the components of the communication unit 33 may be shared components. For example, the memory unit 50, the data processing unit 51, the wireless control unit 52, and the modulation / demodulation unit 53 may be shared.

[0020] The wireless I / F units 56-1 to 56-N, the amplifier units 57-1 to 57-N, and the antennas 58-1 to 58-N may be grouped together, each having the same sub-number, and each group may be one component. Also, the functions of the amplifier units 57-1 to 57-N may be included in the wireless I / F units 56-1 to 56-N.

[0021] In the following, when there is no need to distinguish between the communication units 33-1 to 33-3, they will be simply referred to as the communication unit 33. Furthermore, when there is no need to distinguish between the wireless I / F units 56-1 to 56-N, the amplifier units 57-1 to 57-N, and the antennas 58-1 to 58-N, they will be simply referred to as the wireless I / F unit 56, the amplifier unit 57, and the antenna 58.

[0022] The control unit 31 is configured with a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The control unit 31 executes programs stored in the ROM, etc., and controls the power supply unit 32 and the wireless control units 52 of each communication unit 33.

[0023] The power supply unit 32 is configured by a battery power supply or a fixed power supply, and supplies power to the entire wireless communication device 11 .

[0024] The memory unit 50 holds data input from the upper layer and outputs it to the data processing unit 51. The memory unit 50 also holds data supplied from the data processing unit 51 and outputs it to the upper layer. A part of the memory unit 50 is arranged as a memory unit 35 in the wireless communication device 11 outside the communication unit 33.

[0025] At the time of transmission, the data processing unit 51 generates packets for wireless transmission using data supplied from the memory unit 50. The data processing unit 51 performs processing on the generated packets, such as adding a header for media access control (MAC) and an error detection code, and outputs the processed data to the modem unit 53.

[0026] During reception, the data processing unit 51 performs MAC header analysis, packet error detection, reordering, and other processing on the data supplied from the modem unit 53, and outputs the processed data to the memory unit 50.

[0027] The wireless control unit 52 exchanges information between the various units of the wireless communication device 11 and controls the various units within the communication unit 33. The wireless control unit 52 is made up of a transmission control unit 61 and a reception control unit 62.

[0028] During transmission, the transmission control unit 61 sets parameters in the modulation / demodulation unit 53 and signal processing unit 54, schedules packets in the data processing unit 51, and sets parameters and controls transmission power in the wireless I / F unit 56 and amplifier unit 57, as necessary. During reception, the reception control unit 62 sets parameters in the modulation / demodulation unit 53 and signal processing unit 54, and sets parameters in the wireless I / F unit 56 and amplifier unit 57, as necessary.

[0029] In particular, the transmission control unit 61 performs cooperative transmission of data with other APs based on a cooperative transmission start signal received from the Master AP, which indicates the start of cooperative transmission. The cooperative transmission start signal includes response setting information that sets a transmission method for the transmission result of the cooperative transmission.

[0030] The transmission control unit 61 determines the transmission result of the cooperative transmission based on an acknowledgment signal, which is a Block Ack indicating receipt of data received from the STA. The transmission control unit 61 generates a transmission result response signal that includes information about the acknowledgment signal and indicates the determined transmission result. The transmission control unit 61 controls each unit to transmit the transmission result response signal based on response setting information included in the cooperative transmission start signal.

[0031] The reception control unit 62 controls each unit to receive a coordinated transmission start signal transmitted from the Master AP. The reception control unit 62 controls each unit to receive an acknowledgment signal transmitted from the STA. The reception control unit 62 controls each unit to receive a coordinated transmission end signal transmitted from the Master AP, which indicates the end of coordinated transmission.

[0032] At least some of the operations of wireless control unit 52 may be performed by control unit 31 instead of wireless control unit 52. Furthermore, control unit 31 and wireless control unit 52 may be configured as a single block.

[0033] During transmission, modem unit 53 generates a data symbol stream by encoding, interleaving, and modulating the data supplied from data processing unit 51 based on the encoding method and modulation method set by control unit 31. Modem unit 53 outputs the generated data symbol stream to signal processing unit 54.

[0034] During reception, the modem unit 53 demodulates, deinterleaves, and decodes the data symbol stream supplied from the signal processing unit 54 , and outputs the resulting data to the data processing unit 51 or the radio control unit 52 .

[0035] During transmission, the signal processing unit 54 performs signal processing for spatial separation on the data symbol stream supplied from the modem unit 53 as necessary, and outputs one or more transmission symbol streams obtained as a result of the signal processing to the respective wireless I / F units 56.

[0036] During reception, the signal processing unit 54 performs signal processing on the received symbol streams supplied from each wireless I / F unit 56, performs spatial separation of the streams as necessary, and outputs the data symbol stream obtained as a result of the spatial separation to the modulation / demodulation unit 53.

[0037] The channel estimation unit 55 calculates complex channel gain information of the propagation path from the preamble portion and the training signal portion of the received symbol stream supplied from each wireless I / F unit 56. The complex channel gain information is supplied to the modulation / demodulation unit 53 and the signal processing unit 54 via the wireless control unit 52, and is used for demodulation processing in the modulation / demodulation unit 53 and for spatial separation processing in the signal processing unit 54.

[0038] During transmission, the wireless I / F unit 56 converts the transmission symbol stream from the signal processing unit 54 into an analog signal, performs filtering, upconversion to the carrier frequency, and phase control, and outputs the analog signal after phase control to the amplifier unit 57.

[0039] During reception, the wireless I / F unit 56 performs phase control, down-conversion, and inverse filtering on the analog signal supplied from the amplifier unit 57, converts it into a digital signal, and outputs the resulting received symbol stream to the signal processing unit 54 and the channel estimation unit 55.

[0040] During transmission, amplifier unit 57 amplifies the analog signal supplied from wireless I / F unit 56 to a predetermined power and outputs the amplified analog signal to antenna 58. During reception, amplifier unit 57 amplifies the analog signal supplied from antenna 58 to a predetermined power and outputs the amplified analog signal to wireless I / F unit 56.

[0041] At least a part of at least one of the transmission function and the reception function of the amplifier unit 57 may be included in the wireless I / F unit 56. Furthermore, at least a part of at least one of the functions of the amplifier unit 57 may be a component outside the communication unit 33.

[0042] The configuration of the wireless communication terminal 12 operating as the STA is basically the same as that of the wireless communication device 11, and therefore the configuration of the wireless communication device 11 will be used in the following description of the wireless communication terminal 12.

[0043] In this case, the transmission control unit 61 controls the transmission of a data reception confirmation signal to AP1 and AP2. The reception control unit 62 controls each unit to receive the data cooperatively transmitted from AP1 and AP2.

[0044] Furthermore, the configuration of the communication control device 13 operating as the Master AP is basically the same as that of the wireless communication device 11, and therefore the configuration of the wireless communication device 11 will be used in the following description of the communication control device 13.

[0045] In this case, the transmission control unit 61 controls the transmission of a cooperative transmission start signal to AP1 and AP2. The transmission control unit 61 determines whether the cooperative transmission is completed based on the transmission result response signals received from AP1 and AP2. If the cooperative transmission is completed, the transmission control unit 61 controls the transmission of a cooperative transmission end signal to AP1 and AP2. If the cooperative transmission is not completed, the transmission control unit 61 controls the transmission of a cooperative transmission start signal for retransmission data of the cooperative transmission.

[0046] The reception control unit 62 controls the reception of the transmission result response signals transmitted from AP1 and AP2.

[0047] <1. First Embodiment (Example of Transmission of Information Regarding Block Ack)> First, as a first embodiment, an example will be described in which each AP transmits a transmission result response signal including information related to Block Ack to the Master AP.

[0048] <Example of a cooperative transmission sequence using this technology> FIG. 3 is a diagram showing a sequence illustrating a series of operations of cooperative transmission according to the present technology.

[0049] The Master AP, AP1, AP2, and STA may confirm in advance whether or not each other supports the operation of the present technology.

[0050] At time t1, the Master AP transmits a Joint Tx Trigger frame to AP1 and AP2. The Joint Tx Trigger frame is a cooperative transmission start signal. In this technology, the Joint Tx Trigger frame contains ACK Scheme information. The ACK Scheme information is response setting information for cooperative transmission.

[0051] At time t2, AP1 and AP2 cooperatively transmit data to the STA based on the information described in the Joint Tx Trigger frame. At this time, the data transmitted by AP1 and AP2 may be the same as shown in FIG. 3, or different data.

[0052] At time t3, the STA that has received the data from AP1 and AP2 transmits a Block Ack, which is a data reception acknowledgement signal, to AP1 and AP2.

[0053] AP1 and AP2 receive Block Acks from the STAs within a predetermined time. At time t4, they send a Joint Tx Response frame, which is a transmission result response signal, to the Master AP based on the ACK Scheme information in the Joint Tx Trigger frame. The Joint Tx Response frame contains information about the Block Ack and indicates the transmission result determined based on the Block Ack. The predetermined time is, for example, the ACK timeout.

[0054] When the Master AP that has received the Joint Tx Response frame from AP1 and AP2 determines that retransmission of data is not necessary based on the Joint Tx Response frame, at time t5, it transmits a Joint Tx End frame, which is a cooperative transmission end signal, to AP1 and AP2. After transmitting the Joint Tx End frame, the cooperative transmission sequence in Figure 3 ends.

[0055] <Example format of Joint Tx Trigger frame> Figure 4 is a diagram showing an example format of the Joint Tx Trigger frame.

[0056] In Figure 4, the Joint Tx Trigger frame consists of fields for Signal Type, Length, Transmit Data ID, Transmit Scheme, Transmit Resource, Transmit Time, and ACK Scheme.

[0057] The field of Signal Type contains information indicating that this frame is a frame related to a cooperative transmission request (cooperative transmission start signal).

[0058] The field of Length contains information related to the length of this frame.

[0059] The field of Transmit Data ID contains information for identifying the data targeted by the cooperative transmission request.

[0060] The field of Transmit Scheme contains information related to the communication method used for transmitting the data targeted by the cooperative transmission request.

[0061] The field of Transmit Resource contains information related to the communication resources used for transmitting the data targeted by the cooperative transmission request.

[0062] The Transmit Time field contains information about the transmission timing of the data that is the subject of the cooperative transmission request.

[0063] The ACK Scheme field contains ACK Scheme information, which is response setting information that sets the method for transmitting information related to the transmission result of cooperative transmission between the Master AP, AP1, and AP2, as described above.

[0064] The ACK Scheme information specifies the timing of transmitting a Joint Tx Response frame, which is a transmission result response signal, to the Master AP after receiving a Block Ack from the STA. The timing can be specified as either transmitting the Joint Tx Response frame immediately (Immediate Block) or after receiving a Joint Tx Response Request frame that requests the Joint Tx Response frame.

[0065] The ACK Scheme information also indicates whether the Joint Tx Response frames are to be transmitted simultaneously or in a time-division manner.

[0066] The ACK scheme information further includes information on the communication resources used by each AP when transmitting simultaneously, and information on the transmission timing of each AP when transmitting in a time-division manner.

[0067] In addition, when instructing a device to send a Joint Tx Response frame after receiving a Joint Tx Response Request frame sent from the Master AP, information such as the communication resources for sending the Joint Tx Response frame is written in the Joint Tx Response Request frame from the Master AP.

[0068] <Example Format of Joint Tx Response Frame> FIG. 5 is a diagram showing an example format of a Joint Tx Response frame.

[0069] In FIG. 5, the Joint Tx Response frame consists of fields of Signal Type, Length, and BlockACK Information.

[0070] The field of Signal Type contains information indicating that this frame is a frame (transmission result response signal) containing information regarding the Block Ack from the STA.

[0071] The field of Length contains information regarding the length of this frame.

[0072] The field of BlockACK Information contains information regarding the Block Ack of the data transmitted in cooperation. When the Block Ack from the STA cannot be received, information indicating that the Block Ack could not be received is described.

[0073] Here, in the sequence of FIG. 3, after receiving the Block Ack, AP1 and AP2 immediately transmit a Joint Tx Response frame to the Master AP. The sequence of FIG. 3 shows a case where the ACK Scheme information described in the Joint Trigger of FIG. 4 contains information instructing that after receiving the Block Ack from the STA, AP1 and AP2 immediately transmit a Joint Tx Response frame using different communication resources simultaneously.

[0074] <Other Sequence Examples of Cooperative Transmission of this Technology> FIG. 6 is a diagram showing other sequences of cooperative transmission of this technology.

[0075] Figure 6 shows a sequence in which the ACK Scheme information written in the Joint Trigger of Figure 4 contains information instructing the STA to transmit only after receiving a frame requesting a Joint Tx Response from the Master AP after receiving a Block Ack from the STA.

[0076] At time t11, the Master AP transmits a Joint Tx Trigger frame to AP1 and AP2.

[0077] At time t12, AP1 and AP2 cooperatively transmit data to the STA based on the information described in the Joint Tx Trigger frame.

[0078] The STA that has received the data from AP1 and AP2 transmits a Block Ack to AP1 and AP2 at time t13.

[0079] At time t14, the Master AP transmits a Joint Tx Response Request frame to AP1 and AP2. The Joint Tx Response Request frame is a frame in which the Master AP requests a Joint Tx Response frame that includes information about the Block Ack.

[0080] At time t15, AP1 and AP2, which have received the Joint Tx Response Request frame, transmit a Joint Tx Response frame to the Master AP based on the ACK Scheme information written in the Joint Tx Trigger frame.

[0081] The Master AP that has received the Joint Tx Response frame from AP1 and AP2, if it determines based on the Joint Tx Response frame that retransmission of data is not necessary, transmits a Joint Tx End frame to AP1 and AP2 at time t16. After transmitting the Joint Tx End frame, the cooperative transmission sequence in FIG. 6 ends.

[0082] If the Master AP cannot receive a Joint Tx Response from either AP1 or AP2, it may transmit a Joint Tx Response Request to request retransmission of the Joint Tx Response from AP1 and AP2. In that case, a different transmission method and different communication resources may be specified from those at the time of the previous Joint Tx Response transmission.

[0083] <Example format of Joint Tx Response Request frame> FIG. 7 is a diagram showing an example format of the Joint Tx Response Request frame.

[0084] In FIG. 7, the Joint Tx Response Request frame consists of fields for Signal Type, Length, Request Data ID, Transmit Scheme, Transmit Resource, and Transmit Time.

[0085] The Signal Type field contains information indicating that this frame is a frame (transmission result request signal) for requesting transmission of a Joint Tx Response frame from the STA.

[0086] The Length field contains information regarding the length of this frame.

[0087] The Request Data ID field contains information for identifying the Ack targeted by the transmission request.

[0088] The field of Transmit Scheme includes information regarding the communication method used for transmitting the Response targeted by the transmission request.

[0089] The field of Transmit Resource includes information regarding the communication resource used for transmitting the Response targeted by the transmission request.

[0090] The field of Transmit Time includes information regarding the timing of transmitting the Response targeted by the transmission request.

[0091] <Format Example of Joint Tx End Frame> FIG. 8 is a diagram showing a format example of the Joint Tx End frame.

[0092] In FIG. 8, the Joint Tx End frame consists of fields of Signal Type, Length, and Joint Tx Response Information.

[0093] The field of Signal Type includes information indicating that this frame is a frame for ending the cooperative transmission (cooperative transmission end signal).​​​​​​​​

[0096] By transmitting the Joint Tx End frame, as described conventionally, even when AP1 fails to receive the Block Ack from the STA and only AP2 receives the Block Ack from the STA, the transmission result of the cooperative transmission is notified to AP1. Therefore, it is possible to prevent AP1 from determining that retransmission is necessary and retransmitting the data. Also, for retransmission, the data remaining in the buffer of AP1 can be deleted.

[0097] When the Master AP that has received the Joint Tx Response frame from AP1 and AP2 determines that retransmission of the data is necessary based on the information regarding the Block Ack, a Joint Tx Trigger frame for retransmission is transmitted. At that time, in addition to the information of the Joint Tx End frame, a Joint Tx End + Trigger frame describing the information of the Joint Tx Trigger frame may be transmitted. Note that when retransmitting all the data, the initially transmitted Joint Tx Trigger frame and the Joint Tx Trigger frame for retransmission may be the same.

[0098] On the other hand, when it is determined that retransmission is not necessary, only the Joint Tx End is transmitted without transmitting the Joint Tx Trigger frame.

[0099] <Operation example of Master AP> FIG. 9 is a flowchart for explaining the cooperative transmission process of the Master AP.

[0100] In step S11, the transmission control unit 61 controls each unit to transmit the Joint Tx Trigger frame.

[0101] In step S12, the transmission control unit 61 determines whether or not Immediate Block Ack is specified in the ACK Scheme information of the Joint Tx Trigger. If it is determined in step S12 that Immediate Block Ack is not specified, the process proceeds to step S13.

[0102] In step S13, the transmission control unit 61 controls each unit to transmit a Joint Tx Response Request frame.

[0103] If it is determined in step S12 that Immediate Block Ack is specified, step S13 is skipped and the process proceeds to step S14.

[0104] The AP that receives the Joint Tx Response Request frame transmits a Joint Tx Response frame (step S55 in FIG. 10, which will be described later).

[0105] In step S14, the reception control unit 62 determines whether or not a Joint Tx Response frame has been received. If it is determined in step S14 that a Joint Tx Response frame has not been received, the process returns to step S13, and the subsequent processes are repeated.

[0106] If it is determined in step S14 that a Joint Tx Response frame has been received, the process proceeds to step S15.

[0107] In step S15, the transmission control unit 61 determines whether retransmission is necessary. If it is determined in step S15 that retransmission is necessary, the process proceeds to step S16.

[0108] In step S16, the transmission control unit 61 transmits a frame consisting of Joint Tx End and Joint Tx Trigger. In this case, Joint Tx Trigger is a trigger to start cooperative transmission for retransmission. Then, the process returns to step S12, and the subsequent processing is repeated.

[0109] In step S15, if the transmission control unit 61 determines that retransmission is not necessary, the process proceeds to step S17.

[0110] In step S17, the transmission control unit 61 transmits a Joint Tx End frame. After transmitting the Joint Tx End frame, the cooperative transmission process in FIG. 9 ends.

[0111] <Operation example of AP> FIG. 10 is a flowchart for explaining the cooperative transmission process of the AP.

[0112] The Master AP sends a Joint Tx Trigger frame (step S11 in FIG. 9). In step S51, the reception control unit 62 controls each unit to receive the Joint Tx Trigger frame.

[0113] In step S52, the transmission control unit 61 controls each unit to transmit data in cooperation with other APs based on the Joint Tx Trigger.

[0114] In step S53, the reception control unit 62 determines whether Immediate Block Ack is specified in the ACK Scheme information of the Joint Tx Trigger. If it is determined in step S53 that Immediate Block Ack is not specified, the process proceeds to step S54.

[0115] If Immediate Block Ack is not specified, the Master AP transmits a Joint Tx Response Request frame (step S13 in FIG. 9).

[0116] In step S54, the reception control unit 62 controls each unit to receive the Joint Tx Response Request frame transmitted by the Master AP. After receiving the Joint Tx Response Request frame, the process proceeds to step S55.

[0117] Also, if it is determined in step S53 that Immediate Block Ack is specified, step S54 is skipped and the process proceeds to step S55.

[0118] In step S55, the transmission control unit 61 controls each unit to transmit a Joint Tx Response frame.

[0119] Thereafter, based on the Joint Tx Response, the Master AP transmits a Joint Tx End frame (step S17 in FIG. 9) or a frame consisting of a Joint Tx End and a Trigger (step S16 in FIG. 9).

[0120] In step S56, the reception control unit 62 determines whether the type of frame received from the Master AP is a Joint Tx End frame. If it is determined in step S56 that the frame is not a Joint Tx End frame, there is data to be retransmitted, so the process returns to step S52 and the subsequent processes are repeated.

[0121] If it is determined in step S56 that the frame is a Joint Tx End frame, the AP cooperative transmission process in FIG. 10 ends.

[0122] As described above, in the first embodiment, when multiple APs cooperate to transmit data under the control of the Master AP, it is possible to prevent unnecessary retransmission of data, such as when a certain AP fails to receive an ACK from the STA.

[0123] <2. Second Embodiment (Example of Transmission with Buffer Amount)> Next, as a second embodiment, an example will be described in which each AP transmits a transmission result response signal including information about its own buffer to the Master AP in addition to information regarding Block Ack.

[0124] The AP cooperatively transmits data to the STA as shown in FIGS. 3 and 6 according to the instruction of the Master AP, receives a Block Ack from the STA, and transmits a Joint Tx Response frame to the Master AP. In the second embodiment, when transmitting the Joint Tx Response frame to the Master AP, the AP also includes information about its own buffer in the transmission.

[0125] <Format Example of Joint Tx Response Frame> FIG. 11 is a diagram showing a format example of the Joint Tx Response frame in the case of the second embodiment.

[0126] In FIG. 11, the Joint Tx Response frame consists of fields of Signal Type, Length, Block Ack Information, and Buffer Information. Regarding the parts that are the same as the format example in FIG. 5, the description will be omitted.

[0127] The Buffer Information field contains information about the AP's buffer. The buffer information is, for example, buffer information indicating the data held in the buffer. Specifically, the buffer information is information indicating whether the data corresponding to the information in the BlockAck Information is still present in the buffer or whether it has already been discarded.

[0128] 11, the Master AP determines that data retransmission is necessary based on the information described in the BlockAck Information of AP1 and AP2. However, if the Master AP next determines from the Buffer Information that the data requiring retransmission has already been discarded in AP1, for example, it does not request retransmission from AP1, but generates a Joint Tx Trigger for the retransmission data to AP2 in order to request retransmission only from AP2, which has not discarded the data.

[0129] Furthermore, if data remains in the buffer of one of the APs but retransmission is not necessary, the Master AP may take the following action: For example, the Master AP may write only the information about the relevant data in the Joint Tx Response Information of the Joint Tx End frame in Fig. 8, and cause the data to be discarded from the buffer of each AP.

[0130] In the second embodiment described above, when each AP discards packets due to reaching the retransmission limit, for example, the Master AP can be prevented from instructing each AP to retransmit data that cannot be retransmitted.

[0131] 3. Third Embodiment (Example of Inducing Transmission by STA) Next, as a third embodiment, an example in which a STA induces each AP to transmit a transmission result response signal to a Master AP will be described.

[0132] <Example of a cooperative transmission sequence using this technology> FIG. 12 is a diagram showing another sequence of cooperative transmission according to the present technology.

[0133] At time t21, the Master AP transmits a Joint Tx Trigger frame to AP1 and AP2, as in the example of Fig. 3. At this time, the ACK Scheme information does not need to describe the ACK transmission method; if it does, it should describe that the method is specified by the STA.

[0134] At time t22, AP1 and AP2 cooperatively transmit data to the STA based on the information described in the Joint Tx Trigger frame.

[0135] At time t23, the STA that received the data from AP1 and AP2 aggregates (concatenates) and transmits a Block Ack, which is a response signal confirming receipt of the data, and a Joint Tx Trigger. This triggers each AP to transmit a Joint Tx Response frame, which is a transmission result response signal. At this time, the ACK Scheme information indicates that an Ack will not be transmitted (No Ack).

[0136] At time t24, AP1 and AP2 transmit a Joint Tx Response frame to the Master AP based on the ACK Scheme information written in the Joint Tx Trigger frame transmitted from the STA.

[0137] Upon receiving the Joint Tx Response frames from AP1 and AP2, if the Master AP determines based on the Joint Tx Response frames that data retransmission is not necessary, it transmits a Joint Tx End frame indicating the end of cooperative transmission to AP1 and AP2 at time t25. After transmitting the Joint Tx End frame, the cooperative transmission sequence in FIG. 12 ends.

[0138] At the above-mentioned time t23, either the Block Ack or the Joint Tx Trigger may be aggregated and transmitted first.

[0139] By transmitting a Block Ack before a Joint Tx Trigger, the contents of the Joint Tx Response to be sent by AP1 and AP2 can be immediately determined. On the other hand, by transmitting a Joint Tx Trigger before a Block Ack, surrounding communication terminals can immediately determine that a Joint Tx Response will be sent from AP1 or AP2.

[0140] In the above third embodiment, a Joint Tx Trigger is sent along with the Block Ack, so that the reception status of the Block Ack at each AP can be immediately notified to the Master AP, thereby preventing the retransmission of data that does not need to be retransmitted.

[0141] As described above, in this technology, the Master AP controls the transmission of response setting information to AP1 and AP2, which sets the method for transmitting the transmission results of collaborative transmission by AP1 and AP2 to the STA, thereby preventing the retransmission of data that does not need to be retransmitted.

[0142] <4. Fourth Embodiment (Computer)> <Example of computer configuration> The above-described series of processes can be executed by hardware or software. When the series of processes is executed by software, the program constituting the software is installed from a program recording medium into a computer incorporated in dedicated hardware or a general-purpose personal computer.

[0143] FIG. 13 is a block diagram showing an example of the hardware configuration of a computer that executes the above-described series of processes using a program.

[0144] A CPU (Central Processing Unit) 301 , a ROM (Read Only Memory) 302 , and a RAM (Random Access Memory) 303 are interconnected by a bus 304 .

[0145] An input / output interface 305 is also connected to the bus 304. An input unit 306 including a keyboard, a mouse, etc., and an output unit 307 including a display, a speaker, etc. are connected to the input / output interface 305. In addition, a storage unit 308 including a hard disk, a nonvolatile memory, etc., a communication unit 309 including a network interface, etc., and a drive 310 that drives removable media 311 are also connected to the input / output interface 305.

[0146] In the computer configured as above, the CPU 301 loads a program stored in the storage unit 308 into the RAM 303 via the input / output interface 305 and the bus 304 and executes the program, thereby performing the above-described series of processes.

[0147] The program executed by the CPU 301 is installed in the storage unit 308 by being recorded on a removable medium 311, or provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital broadcasting.

[0148] The program executed by the computer may be a program that processes in chronological order according to the order described in this specification, or may be a program that processes in parallel or at the required timing, such as when called.

[0149] In this specification, a system refers to a collection of multiple components (devices, modules (components), etc.), regardless of whether all the components are contained in the same housing. Therefore, multiple devices housed in separate housings and connected via a network, and a single device housed in a single housing with multiple modules, are both systems.

[0150] Furthermore, the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0151] The embodiments of the present technology are not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present technology.

[0152] For example, this technology can be configured as cloud computing, in which a single function is shared and processed collaboratively by multiple devices via a network.

[0153] Furthermore, each step described in the above flowchart can be executed by one device, or can be shared and executed by multiple devices.

[0154] Furthermore, when one step includes multiple processes, the multiple processes included in that one step can be executed by one device or can be shared and executed by multiple devices.

[0155] <Configuration combination example> The present technology can also be configured as follows. (1) a communication unit that communicates with the first wireless communication device and the second wireless communication device; a control unit that controls transmission of response setting information, in which a transmission method of a transmission result of cooperative transmission by the first wireless communication device and the second wireless communication device to a wireless communication terminal, to the first wireless communication device and the second wireless communication device; A communication control device comprising: (2) The control unit controls transmission of a first cooperative transmission start signal that includes the response setting information and controls the first wireless communication device and the second wireless communication device to perform the cooperative transmission to the wireless communication terminal. The communication control device according to (1) above. (3) The control unit controls reception of a transmission result response signal that includes information regarding an acknowledgment signal transmitted from the wireless communication terminal and that indicates a transmission result of the cooperative transmission, the transmission result response signal being transmitted from the first wireless communication device and the second wireless communication device based on the response setting information. The communication control device according to (1) and (2). (4) The control unit performs control to determine whether or not to transmit a second cooperative transmission start signal to the first wireless communication device and the second wireless communication device based on the transmission result response signal. (5) When determining not to transmit the second coordinated transmission start signal based on the transmission result response signal, the control unit controls transmission of a coordinated transmission end signal indicating an end of the coordinated transmission. The communication control device according to (4) above. (6) When it is determined to transmit the second cooperative transmission start signal based on the transmission result response signal, the control unit generates the second cooperative transmission start signal so as to include a cooperative transmission end signal indicating the end of the cooperative transmission, and controls transmission of the second cooperative transmission start signal. The communication control device according to (4) above. (7) When determining to transmit the second coordinated transmission start signal based on the transmission result response signal, the control unit controls transmission of the second coordinated transmission start signal to perform control to retransmit the coordinated transmission. The communication control device according to (4) above. (8) The control unit controls transmission of the response setting information indicating a transmission method of the transmission result response signal. A communication control device according to any one of (3) to (7). (9) When the transmission result response signal includes buffer information related to data held in a buffer of the first wireless communication device or the second wireless communication device, the control unit controls generation of a second cooperative transmission start signal including information indicating retransmission data to be retransmitted from the data held in the buffer, based on the transmission result response signal. (8) A communication control device according to (8). (10) the control unit controls transmission of a transmission result request signal requesting the transmission result response signal; and performing control to receive the transmission result response signals transmitted from the first wireless communication device and the second wireless communication device based on the transmission result request signal. The communication control device according to (3) above. (11) The control unit controls transmission of the transmission result request signal including at least one of information indicating a request for the transmission result response signal, information indicating a transmission method of the transmission result response signal for the cooperative transmission, or radio resources used for the response. The communication control device according to (10) above. (12) The control unit controls transmission of the response setting information including radio resources used by the first wireless communication device and the second wireless communication device to transmit the transmission result response signal. The communication control device according to any one of (3) to (11). (13) A communication control device communicating with a first wireless communication device and a second wireless communication device; Control is performed to transmit, to the first wireless communication device and the second wireless communication device, response setting information in which a transmission method of a transmission result of cooperative transmission by the first wireless communication device and the second wireless communication device to a wireless communication terminal is set. Communication control method. (14) a communication unit that communicates with the communication control device and other wireless communication devices; a control unit that controls receiving a cooperative transmission start signal that controls the communication control device to perform cooperative transmission, controls a wireless communication terminal to perform the cooperative transmission with the other wireless communication device based on the cooperative transmission start signal, and controls transmitting a transmission result response signal including information about a reception confirmation signal of the wireless communication terminal in response to the cooperative transmission to the communication control device; A wireless communication device comprising: (15) The control unit performs control to receive response setting information relating to a transmission method of the transmission result response signal from the communication control device, and performs control to transmit the transmission result response signal to the communication control device based on the response setting information. The wireless communication device according to (14). (16) the control unit controls reception of a transmission result request signal from the communication control device; Based on the transmission result request signal, control is performed to transmit the transmission result response signal to the communication control device. The wireless communication device according to (14) or (15). (17) When the control unit does not receive the acknowledgement signal from the wireless communication terminal, the control unit controls to transmit the transmission result response signal indicating that the cooperative transmission has failed to the communication control device. The wireless communication device according to any one of (14) to (16). (18) The control unit controls transmission of the transmission result response signal including buffer information related to data held in a buffer. The wireless communication device according to any one of (14) to (17). (19) Wireless communication device Communicating with the communication control device and other wireless communication devices; The control unit controls the communication control device to receive a cooperative transmission start signal that controls the communication control device to perform cooperative transmission, controls the wireless communication terminal to perform the cooperative transmission with the other wireless communication device based on the cooperative transmission start signal, and controls the wireless communication terminal to transmit a transmission result response signal that includes information about a reception confirmation signal of the wireless communication terminal in response to the cooperative transmission to the communication control device. Wireless communication method. (20) a communication unit that communicates with the first wireless communication device and the second wireless communication device; a control unit that performs control to determine a reception result for data cooperatively transmitted from the first wireless communication device and the second wireless communication device, and control to transmit, to the first wireless communication device and the second wireless communication device, control information for causing a reception confirmation signal indicating the reception result and a transmission result response signal including information about the reception confirmation signal to be transmitted to a communication control device; A wireless communication terminal comprising: [Explanation of symbols]

[0156] 11 wireless communication device, 12 wireless communication terminal, 13 wireless control device, 31 control unit, 32 power supply unit, 33 communication unit, 35 memory unit, 50 memory unit, 51 data processing unit, 52 wireless control unit, 53 modulation / demodulation unit, 54 signal processing unit, 55 channel estimation unit, 56-1 to 56-N wireless I / F unit, 57-1 to 57-N amplifier unit, 58-1 to 58-N antenna

Claims

[Claim 1] a communication unit that communicates with the first wireless communication device and the second wireless communication device; a control unit that performs control to transmit response setting information, in which a transmission method of a transmission result of cooperative transmission by the first wireless communication device and the second wireless communication device to a wireless communication terminal, to the first wireless communication device and the second wireless communication device; control to receive a transmission result response signal indicating the transmission result of the cooperative transmission from at least one of the first wireless communication device and the second wireless communication device based on content described in the response setting information; control to determine whether or not to retransmit the cooperative transmission based on the received transmission result response signal; and control to transmit a signal indicating completion of the cooperative transmission to the first wireless communication device and the second wireless communication device when it is determined that retransmission of the cooperative transmission is not necessary. A communication control device comprising:

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