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EP-3998794-B1 - COMMUNICATION CONTROL DEVICE AND METHOD, WIRELESS COMMUNICATION DEVICE AND METHOD, AND WIRELESS COMMUNICATION TERMINAL

EP3998794B1EP 3998794 B1EP3998794 B1EP 3998794B1EP-3998794-B1

Inventors

  • HIRATA RYUICHI
  • AIO KOSUKE

Dates

Publication Date
20260506
Application Date
20200626

Claims (12)

  1. A communication control device (13) controlling a plurality of access points, the communication control device comprising: a communication unit (33) that is configured to communicate with a first access point (11-1) and a second access point (11-2); and a control unit (31) that is configured to perform: control to transmit a first coordinated transmission start signal for controlling the first access point and the second access point to perform a coordinated transmission to a wireless communication terminal, the coordinated transmission start signal including response setting information, the response setting information including: information identifying target data to be transmitted, and information identifying a transmission method to be used to transmit the target data via coordinated transmission to a wireless communication terminal by the first access point and the second access point; control to receive a transmission result response signal from each of the first access point and the second access point, the transmission result response signal including: information regarding a receipt confirmation signal, the receipt confirmation signal indicating that the target data has been received by the wireless communication terminal, and buffer information, the buffer information including information regarding data held in a buffer of the first access point or the second access point; and control to transmit, based on the transmission result response signal, a second coordinated transmission start signal for controlling the first access point or the second access point to perform retransmission to the wireless communication terminal, the second transmission start signal including information identifying, from within the data held in the buffer, any of the target data to be retransmitted.
  2. The communication control device according to claim 1, wherein the control unit is configured to perform control to determine whether to transmit a second coordinated transmission start signal to the first access point and the second access point on the basis of the transmission result response signal.
  3. The communication control device according to claim 2, wherein the control unit is configured to perform control to transmit a coordinated transmission end signal indicating the end of the coordinated transmission when it is determined that the second coordinated transmission start signal is not to be transmitted on the basis of the transmission result response signal.
  4. The communication control device according to claim 2, wherein when it is determined that the second coordinated transmission start signal is to be transmitted on the basis of the transmission result response signal, the control unit is configured to perform control to generate and transmit the second coordinated transmission start signal so as to include a coordinated transmission end signal indicating the end of the coordinated transmission.
  5. The communication control device according to claim 2, wherein when it is determined that the second coordinated transmission start signal is to be transmitted on the basis of the transmission result response signal, the control unit is configured to perform control to transmit the second coordinated transmission start signal for performing control to retransmit the coordinated transmission.
  6. The communication control device according to claim 1, wherein: the control unit performs control to transmit the response setting information indicating a transmission method of the transmission result response signal, and when the transmission result response signal includes buffer information regarding data held in a buffer of the first access point or the second access point, the control unit performs control to generate a second coordinated transmission start signal including information indicating retransmission data to be transmitted again from the data held in the buffer on the basis of the transmission result response signal.
  7. The communication control device according to claim 1, wherein the control unit is configured to perform control to transmit a transmission result request signal for requesting the transmission result response signal and performs control to receive the transmission result response signal transmitted from the first access point and the second access point on the basis of the transmission result request signal, and the control unit is configured to perform control to transmit the transmission result request signal including at least one of information indicating that the transmission result response signal is requested, information indicating a transmission method of the transmission result response signal for the coordinated transmission, and radio resources used for the response.
  8. A communication control method implemented by the communication control device (13) controlling a plurality of access points, the method comprising: allowing a communication unit (33) to communicate with a first access point (11-1) and a second access point (11-2); performing (S11) control to transmit response setting information to the first access point and the second access point, the response setting information including: information identifying target data to be transmitted, and information identifying a transmission method to be used to transmit the target data via coordinated transmission to a wireless communication terminal by the first access point and the second access point is set; performing (S14) control to receive a transmission result response signal from each of the first access point and the second access point, the transmission result response signal including: information regarding a receipt confirmation signal, the receipt confirmation signal indicating that the target data has been received by the wireless communication terminal, and buffer information, the buffer information including information regarding data held in a buffer of the first access point or the second access point; and performing (S16) control to transmit, based on the transmission result response signal, a second coordinated transmission start signal for controlling the first access point or the second access point to perform retransmission to the wireless communication terminal, the second transmission start signal including information identifying, from within the data held in the buffer, any of the target data to be retransmitted.
  9. An access point (11) comprising: a communication unit (33) that is configured to communicate with a communication control device (13) controlling a plurality of access points and communicate with another access point (11-1, 11-2); and a control unit (31) that is configured to perform: control to receive, from the communication control device, a coordinated transmission start signal for controlling the access point to perform coordinated transmission of target data to a wireless communication terminal, control to cause the access point to perform the coordinated transmission with the other access point to the wireless communication terminal on the basis of the coordinated transmission start signal, control to receive a receipt confirmation signal from the wireless communication terminal, the receipt confirmation signal indicating that the target data has been received by the wireless communication terminal, and control to transmit a transmission result response signal to the communication control device, the transmission result response signal including: information regarding the receipt confirmation signal, and buffer information, the buffer information including information regarding data held in a buffer of the access point.
  10. The access point according to claim 9, wherein the control unit is configured to perform control to receive response setting information regarding a transmission method of the transmission result response signal from the communication control device and perform control to transmit the transmission result response signal to the communication control device on the basis of the response setting information.
  11. The access point according to claim 9, wherein the control unit is configured to perform control to receive a transmission result request signal from the communication device and performs control to transmit the transmission result response signal to the communication control device on the basis of the transmission result request signal.
  12. A wireless communication method implemented by the access point according to claim 9, the method comprising: allowing a access point to communicate with a communication control device (13) controlling plurality of access points and communicate with another access point (11-1, 11-2); and performing: control (S51) to receive, from the communication control device, a coordinated transmission start signal for controlling the access point to perform coordinated transmission of target data to a wireless communication terminal, control (S52) to cause the access point to perform the coordinated transmission with the other access point to the wireless communication terminal on the basis of the coordinated transmission start signal, control to receive a receipt confirmation signal from the wireless communication terminal, the receipt confirmation signal indicating that the target data has been received by the wireless communication terminal, and control (S55) to transmit a transmission result response signal to the communication control device, the transmission result response signal including: information regarding the receipt confirmation signal , and buffer information, the buffer information including information regarding data held in a buffer of the access point.

Description

[Technical Field] The present technology relates to communication control devices and methods, wireless communication devices and methods, and wireless communication terminals, and more particularly to communication control devices and methods, wireless communication devices and methods, and wireless communication terminals that can prevent retransmission of data that does not need to be retransmitted. [Background Art] In recent years, access points (hereinafter referred to as APs) are increasingly being placed densely not only in public facilities such as stadiums but also in homes. For this reason, technologies that improve system throughput and reliability by coordination of APs are attracting attention. For coordination of APs, there may be an AP (Master AP) that manages the APs. One of the AP-to-AP coordination technologies is Joint Transmission, in which data is simultaneously transmitted from a plurality of APs to one terminal (STA). When AP1 and AP2 perform coordinated transmission according to an instruction from the Master AP, AP1 and AP2 coordinate to transmit data to STA. Then, the STA that has received the data transmits ACK, which is an acknowledgment of the data. In addition, PTL 1 describes a technique for controlling a modulation coding method on the basis of ACK. [Citation List] [Patent Literature] [PTL 1] JP 2015-119232 A. Other previously proposed arrangements are disclosed in WO 2020/261988 A1, EP 3968684 A1 and WO 2014/074919 A1. [Summary] [Technical Problem] The ACK transmitted from STA is received only by AP2. If AP1 fails to receive the ACK, the AP1 may attempt to retransmit the data even though the STA has successfully received the data and the ACK has been transmitted. The present technology has been made in view of such a situation, and prevents retransmission of data that does not need to be retransmitted. [Solution to Problem] The invention is defined according to the independent claims. [Brief Description of Drawings] [Fig. 1] Fig. 1 is a diagram showing a configuration example of a communication system of the present technology.[Fig. 2] Fig. 2 is a block diagram showing a configuration example of a wireless communication device.[Fig. 3] Fig. 3 is a diagram showing a sequence of coordinated transmission of the present technology.[Fig. 4] Fig. 4 is a diagram showing a format example of a Joint Tx Trigger frame.[Fig. 5] Fig. 5 is a diagram showing a format example of a Joint Tx Response frame.[Fig. 6] Fig. 6 is a diagram showing another sequence of coordinated transmission of the present technology.[Fig. 7] Fig. 7 is a diagram showing a format example of a Joint Tx Response Request frame.[Fig. 8] Fig. 8 is a diagram showing a format example of a Joint Tx End frame.[Fig. 9] Fig. 9 is a flowchart illustrating a coordinated transmission process of a Master AP.[Fig. 10] Fig. 10 is a flowchart illustrating a coordinated transmission process of APs.[Fig. 11] Fig. 11 is a diagram showing a format example of a Joint Tx Response frame in the case of a second embodiment.[Fig. 12] Fig. 12 is a diagram showing another sequence of coordinated transmission of the present technology.[Fig. 13] Fig. 13 is a block diagram showing a configuration example of a computer. [Description of Embodiments] Hereinafter, embodiments of the present technology will be described. Note that the description will be given in the following order. 0. Configuration Example of System and Device1. First Embodiment (Example of Transmission of Information Regarding Block Ack)2. Second Embodiment (Example in Which Buffer Amount is Also Transmitted)3. Third Embodiment (Example of Induction of Transmission by STA)4. Fourth Embodiment (Computer) <0. Configuration Example of System and Device> <Configuration Example of Communication System> Fig. 1 is a diagram showing a configuration example of a communication system according to an embodiment of the present technology. The communication system of Fig. 1 is configured by connecting access points (hereinafter referred to as APs) 1 and AP2 and a Master AP by wired communication or wireless communication. The communication system is configured by connecting AP1 and AP2 and STA, which is a wireless communication terminal, by wireless communication. AP1 and AP2 are configured of wireless communication devices 11-1 and 11-2 that coordinate to transmit data to the STA. The STA is configured of a wireless communication terminal 12 belonging to a network managed by the APs. The Master AP is configured of a communication control device 13 that controls communication of a plurality of APs. The wireless communication devices 11-1 and 11-2 are referred to as a wireless communication device 11 unless it is necessary to distinguish them. The number and positional relationship of the wireless communication devices in Fig. 1 are examples, and are not limited to the description in Fig. 1. <Configuration Example of Wireless Communication Device> Fig. 2 is a block diagram showing a configuration