Wireless communication device and wireless communication method

Abstract

To improve the utilization efficiency of a transmission path.SOLUTION: A wireless communication device includes a control unit that receives data transmitted from another wireless communication device, adjusts output timing for outputting the received data to a connected application device, generates retransmission request information for requesting retransmission of undelivered data, which is data that has not been delivered among the transmitted data, according to the output timing, and controls transmission of the generated retransmission request information to the other wireless communication device. The present disclosure can be applied to, for example, wireless communication devices that constitute a wireless LAN system.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present disclosure relates to a wireless communication device and a wireless communication method, and more particularly to a wireless communication device and a wireless communication method that enable improved utilization efficiency of a transmission path. [Background technology]

[0002] Currently, the IEEE802.11be standard is not only increasing the amount of data transmission for anticipated applications, but also requires that the data be low latency and highly reliable. As a communication technology for this, the IEEE802.11be standard is currently considering a method of periodically setting R-TWT (Restricted Target Wakeup Time) to transmit low latency data sequentially.

[0003] This R-TWT technology is defined as a technology that realizes low power consumption operation by activating existing targets at a determined time, and is defined as a mechanism in which the transmitting communication device periodically acquires a transmission opportunity (TXOP: Transmit Opportunity) and transmits data that should be transmitted with low latency during that transmission opportunity (TXOP) with priority over other data. R-TWT technology is considered a promising method for transmitting data suitable for real-time applications, and currently technical proposals using this method are being made.

[0004] Patent Document 1 discloses a technique for limiting the time length of communication addressed to other communication devices when requesting TWT operation and the data frame is for low latency communication. Patent Document 2 discloses a technique for setting a transmission period of N periods in a beacon period and overlapping with M periods shorter than that to perform OFDMA communication. Patent Document 3 discloses a technique for performing multi-link communication by including AP Primary Link information in a TWT request as a connection request / reconnection request. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2022-133131 A [Patent Document 2] Patent Publication No. 2021-016059 [Patent Document 3] Special Publication No. 2022-541085 Summary of the Invention [Problem to be solved by the invention]

[0006] The R-TWT technology described above is defined so that the transmitting and receiving communication devices operate in sync at a specified cycle, but it is necessary to set the R-TWT service period (SP) in order to specify a certain cycle and prioritize those communications. When applying these technologies to data that requires low latency, it is necessary to set parameters to complete transmission within the allowable delay time, and there was a risk of transmission delays occurring unless the arrival cycle of the R-TWT SP was shortened.

[0007] In addition, since communication errors may occur on wireless transmission paths, if the data that has experienced a communication error is not resent, it is not possible to reliably deliver all data end-to-end. In particular, when the R-TWT SP is set to secure a single transmission opportunity (TXOP) to ensure the communication volume required for minimum data transmission, it is difficult to resend undelivered data within the service period. Therefore, there is a demand for technology to improve the utilization efficiency of the transmission path when resending such undelivered data.

[0008] The present disclosure has been made in consideration of such circumstances, and makes it possible to improve the utilization efficiency of a transmission path. [Means for solving the problem]

[0009] A wireless communication device of one aspect of the present disclosure is a wireless communication device that has a control unit that receives data transmitted from another wireless communication device, adjusts the output timing of outputting the received data to a connected application device, generates retransmission request information requesting retransmission of undelivered data, which is data that has not been delivered among the transmitted data, according to the output timing, and controls the transmission of the generated retransmission request information to the other wireless communication device.

[0010] A wireless communication method of one aspect of the present disclosure is a wireless communication method in which a wireless communication device receives data transmitted from another wireless communication device, adjusts the output timing of outputting the received data to a connected application device, generates retransmission request information requesting retransmission of undelivered data, which is data that has not been delivered among the transmitted data, in accordance with the output timing, and transmits the generated retransmission request information to the other wireless communication device.

[0011] In a wireless communication device and wireless communication method of one aspect of the present disclosure, data transmitted from another wireless communication device is received, the output timing of outputting the received data to a connected application device is adjusted, and retransmission request information is generated in accordance with the output timing, requesting retransmission of undelivered data, which is the data that has not been delivered among the transmitted data, and the generated retransmission request information is transmitted to the other wireless communication device.

[0012] A wireless communication device of one aspect of the present disclosure is a wireless communication device that transmits data to another wireless communication device, receives retransmission request information transmitted from the other wireless communication device, and has a control unit that controls retransmission to the other wireless communication device of undelivered data identified by the received retransmission request information, which is among the transmitted data, depending on the output timing of outputting the data to an application device connected to the other wireless communication device.

[0013] A wireless communication method of one aspect of the present disclosure is a wireless communication method in which a wireless communication device transmits data to another wireless communication device, receives retransmission request information transmitted from the other wireless communication device, and retransmits to the other wireless communication device, depending on an output timing at which the data is output to an application device connected to the other wireless communication device, undelivered data identified by the received retransmission request information and which has become undelivered among the transmitted data.

[0014] In a wireless communication device and wireless communication method of one aspect of the present disclosure, data is transmitted to another wireless communication device, retransmission request information transmitted from the other wireless communication device is received, and depending on the output timing at which the data is output to an application device connected to the other wireless communication device, undelivered data identified by the received retransmission request information, which is among the transmitted data and has become undelivered, is retransmitted to the other wireless communication device.

[0015] It should be noted that the wireless communication device according to one aspect of the present disclosure may be an independent device, or may be an internal block constituting a single device. [Brief description of the drawings]

[0016] [Figure 1] 1 is a diagram illustrating an example of the configuration of a wireless LAN system to which the present disclosure is applied. [Diagram 2] FIG. 1 is a diagram showing the operation of a conventional R-TWT. [Diagram 3] FIG. 1 is a diagram illustrating problems in wireless communication using a conventional R-TWT SP. [Figure 4] FIG. 1 is a diagram illustrating problems in wireless communication using a conventional R-TWT SP. [Diagram 5] FIG. 1 is a diagram showing an example of an output sequence of a conventional RTA data application. [Figure 6] FIG. 1 illustrates an example of downlink R-TWT SP configuration according to the prior art. [Figure 7]FIG. 13 is a diagram showing a modified example of a downlink R-TWT SP setting example according to the prior art. [Figure 8] FIG. 1 illustrates an example of uplink R-TWT SP configuration according to the prior art. [Figure 9] FIG. 13 is a diagram showing a modified example of an uplink R-TWT SP setting example according to the prior art. [Figure 10] FIG. 13 illustrates an example output sequence of an application of RTA data according to the present disclosure. [Figure 11] FIG. 13 illustrates an example of downlink R-TWT SP configuration according to the present disclosure. [Figure 12] FIG. 13 illustrates an example of an uplink R-TWT SP configuration according to the present disclosure. [Figure 13] FIG. 13 is a diagram showing an example of a buffer configuration when transmitting RTA data using R-TWT SP. [Figure 14] 1 is a block diagram illustrating a configuration example of a wireless communication device to which the present disclosure is applied. [Figure 15] 15 is a block diagram showing a configuration example of the wireless communication module of FIG. 14. [Figure 16] A diagram showing a first example of an exchange sequence of a setup request frame for RTA data exchange. [Figure 17] A figure showing a second example of an exchange sequence of a setup request frame for RTA data exchange. [Figure 18] FIG. 13 illustrates the configuration of an access control parameter setup request element for RTA data according to the present disclosure. [Figure 19] FIG. 13 illustrates the configuration of an access control parameter setup response element for RTA data according to the present disclosure. [Figure 20] FIG. 13 is a diagram illustrating an example of a configuration of a trigger frame according to the present disclosure. [Figure 21] FIG. 2 is a diagram illustrating an example of a data frame configuration according to the present disclosure. [Figure 22] FIG. 13 is a diagram illustrating an example of a configuration of a delimiter of a data frame according to the present disclosure. [Diagram 23] 13 illustrates an example of the configuration of a Block ACK frame according to the present disclosure. FIG. [Figure 24] 13 is a flowchart illustrating the flow of a process for exchanging setup information of RTA parameters. [Diagram 25] 13 is a flowchart illustrating the flow of a process for exchanging setup information of RTA parameters. [Figure 26] 10 is a flowchart illustrating a flow of a transmission process by a transmitting communication device. [Figure 27] 10 is a flowchart illustrating a flow of a transmission process by a transmitting communication device. [Figure 28] 10 is a flowchart illustrating a flow of a receiving process by a receiving communication device. [Figure 29] 10 is a flowchart illustrating a flow of a receiving process by a receiving communication device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] <System configuration> Fig. 1 is a diagram showing a configuration example of a wireless LAN (Local Area Network) system to which the present disclosure is applied. In Fig. 1, the wireless LAN system is composed of a transmitting communication device 10Tx and a receiving communication device 10Rx, one of which operates as an access point (AP) and the other operates as a communication terminal (STA) to configure one basic service set (BSS).

[0018] 1, when a data transmitting communication device 10Tx and a data receiving communication device 10Rx exist, an overlapping BSS (OBSS: Overlapping Basic Service Set) exists as a surrounding network consisting of communication devices 20A and 20B. The communication devices 20A and 20B that constitute the OBSS network do not necessarily conform to the latest standards, and may include legacy communication devices that can only recognize signals of communication methods that were standardized in the past. The following describes the case where the communication devices 20A and 20B are legacy communication devices.

[0019] 1, the white circles represent wireless communication devices to which the present disclosure is applied, their radio wave reach is indicated by dashed lines A1 and A2, and a configuration is shown in which low-latency data transmission is performed from a transmitting communication device 10Tx to a receiving communication device 10Rx using a real-time application (RTA), as indicated by an arrow C1. Also, the black circles represent legacy communication devices constituting the OBSS, and their radio wave reach is indicated by dashed lines A3 and A4.

[0020] Here, the communication devices 20A and 20B, which are legacy communication devices, have difficulty recognizing the communication protocol for real-time applications described in the latest standard, and are unable to grasp that real-time application communication is performed almost periodically, and start communication when they determine that the transmission path is free. In other words, as shown by arrows I1 and I2 in Figure 1, it shows how the transmission signals from the OBSS communication devices 20A and 20B interfere with the data transmission of the real-time application used between the transmitting communication device 10Tx and the receiving communication device 10Rx.

[0021] <Conventional operation> Fig. 2 is a diagram showing the operation of a conventional R-TWT (Restricted Target Wakeup Time). In Fig. 2, the upper part shows a preset R-TWT SP (Service Period), the middle part shows the operation of a transmitting communication device 10Tx that acquires a transmission opportunity in the TWT, and the lower part shows the operation of a receiving communication device 10Rx that receives almost periodically in the TWT, transitioning from left to right over time. Furthermore, in the middle and lower parts, the data transmission operation is shown as a convex upward state, and the data reception operation is shown as a convex downward state, on a time axis corresponding to the time direction.

[0022] Here, as shown by the upper dashed line section, the SP of the R-TWT is set almost periodically in advance, and during the SP period, data of a real-time application (hereinafter also referred to as RTA data) that is assigned a specific identifier, a traffic identifier (TID), can be preferentially transmitted. After the SP period has elapsed, other general data can be transmitted and received, and therefore any data (hereinafter also referred to as other data) can be exchanged. That is, in FIG. 2, during the R-TWT SP period, RTA data #1 to #4 are transmitted, but outside the period, other data #1 to #3 are transmitted. Note that RTA data is also written as RTD, and other data is also written as ND.

[0023] Fig. 3 is a diagram showing problems in wireless communication using a conventional R-TWT SP. Fig. 3 shows the same configuration flow as Fig. 2, and overlapping explanations will be omitted as appropriate. In Fig. 3, when the second R-TWT SP arrives, if the communication device 20A, which exists in an OBSS that cannot grasp the setting of the R-TWT SP, has started signal transmission, the period is treated as a BUSY state. Therefore, even if the SP of the R-TWT arrives, if the transmitting communication device 10Tx is in a BUSY state, it is not possible to transmit the desired RTA data.

[0024] In addition, when the third R-TWT SP arrives, the receiving communication device 10Rx cannot correctly decode the desired RTA data even if data addressed to itself is sent, if the receiving communication device 10Rx receives a strong signal from the OBSS communication device 20B that cannot grasp the setting of the R-TWT SP. Furthermore, when the BUSY state exceeds the R-TWT SP, the data transmission of the real-time application scheduled for that period cannot be performed, and the data is transmitted after performing access control with general data. In this case, the RTA data is not necessarily sent with priority. Figure 3 shows a case where the delay accumulates when the fourth R-TWT SP arrives, and the second RTA data #2 is transmitted.

[0025] Fig. 4 shows another case of problems in wireless communication using conventional R-TWT SP. Fig. 4 shows the same configuration flow as Fig. 2, and duplicated explanations will be omitted as appropriate. Fig. 4 shows a case in which communication is performed by setting the service period (SP) of the R-TWT longer than the case of Fig. 2, taking into account retransmission of RTA data.

[0026] 4 shows a state in which, when the second R-TWT SP arrives, even if the communication device 20A in the OBSS that cannot grasp the setting of the R-TWT SP is in a BUSY state in which signal transmission has started, if the R-TWT SP is set abundantly, the BUSY state is resolved within that period, and the transmitting communication device 10Tx can transmit the desired RTA data #2. Also, in the third R-TWT SP, even if the receiving communication device 10Rx is in a BUSY state, retransmission can be performed within that R-TWT SP, and the desired RTA data #3 can be transmitted periodically. However, since the portion other than the R-TWT SP becomes relatively short, there is a problem in that there are fewer opportunities to transmit data other than the RTA data.

[0027] Fig. 5 is a diagram showing an example of a conventional application output sequence of RTA data. In the sequence diagram of Fig. 5, time passes sequentially from the top to the bottom of the diagram. Also, in the sequence diagram of Fig. 5, when predetermined RTA data arrives almost periodically from the application of the transmitting communication device 10Tx on the left side of the diagram, when data is transmitted through a wireless transmission path, the received RTA data is output to the application of the receiving communication device 10Rx on the right side of the diagram.

[0028] That is, the transmitting communication device 10Tx is configured to transmit RTA data collectively during the period of the R-TWT SP that is set almost periodically, and here, the RTA data #1 to #3 are transmitted using the first R-TWT SP. At this time, if the RTA data #3 does not arrive correctly at the receiving communication device 10Rx, the situation is returned to the transmitting communication device 10Tx via, for example, a block ACK (BA: Block ACK) frame. Next, in the second R-TWT SP, new RTA data #4 to #6 are transmitted including the undelivered RTA data #3. Also, at this time, if the RTA data #6 does not arrive correctly at the receiving communication device 10Rx, the situation is returned to the transmitting communication device 10Tx via, for example, a block ACK frame.

[0029] Furthermore, in the third R-TWT SP, new RTA data #7-#8 are transmitted, including the undelivered RTA data #6. Here again, if the RTA data #7 does not arrive correctly at the receiving communication device 10Rx, this situation is returned to the transmitting communication device 10Tx, for example, via a Block ACK frame. Then, in the fourth R-TWT SP, the undelivered RTA data #7 is retransmitted, and by receiving a Block ACK frame from the receiving communication device 10Rx, the transmitting communication device 10Tx confirms receipt of all data.

[0030] On the other hand, the receiving communication device 10Rx is configured to output the received RTA data to the connected application device at a predetermined timing, and here, an example is shown in which the data is output after the first R-TWT SP in which the first data is received is completed. In other words, if there is undelivered RTA data #3, a delay time occurs until the undelivered data is retransmitted, but at first, these delays are absorbed and the data reaches the application device. However, if the amount of undelivered data increases, the retransmission timing is delayed, and if there are undelivered data #6 and #7 on the way, the RTA data #7 does not arrive, so a delay occurs before the data reaches the application device, as shown by the arrow D1 in the figure.

[0031] Fig. 6 is a diagram showing an example of setting an R-TWT SP of a downlink (DL) according to the conventional technology. In Fig. 6, an access point (AP) is a transmitting communication device 10Tx in the upper part shown in Fig. 6A, and a communication terminal (STA) is a receiving communication device 10Rx in the lower part shown in Fig. 6B, and time is shown as passing from the left side to the right side in the figure. Also, in Fig. 6A and B, a signal to be transmitted is shown as a convex upward and a signal to be received is shown as a convex downward on a time axis corresponding to the time direction, and the time of the R-TWT SP required to communicate the desired RTA data is shown by a broken line.

[0032] That is, the time during which predetermined RTA data can be transmitted in one R-TWT SP is shown by the period P1 indicated by the dashed line. Here, the transmitting communication device 10Tx transmits RTA data (DL RTA Data) in the downlink direction (DL) from the access point (AP) using a predetermined access procedure, and the receiving communication device 10Rx returns a receipt confirmation using a block ACK frame (BA). Here, for convenience, the redundant time of the R-TWT SP including retransmission shown in FIG. 7 described later is shown by the period P2 indicated by the dashed line.

[0033] Fig. 7 is a diagram showing a modified example of a downlink R-TWT SP setting example according to the prior art. Fig. 7 is described in the same manner as Fig. 6, so duplicated explanations will be omitted as appropriate. Fig. 7 shows an example in which a single R-TWT SP is set to include redundant time for retransmission, and the time during which predetermined RTA data can be transmitted in a single R-TWT SP is shown by a period P2 indicated by a dashed line. In this setting example, the period of the R-TWT SP that is originally required is doubled so that the same amount of data can be retransmitted in a single R-TWT SP setting.

[0034] Here, the transmitting communication device 10Tx transmits downstream RTA data (DL RTA Data) using a predetermined access procedure, and the receiving communication device 10Rx returns a receipt confirmation using a Block Ack frame (BA). In addition, assuming a case where all of this RTA data does not arrive, sufficient time is secured for the retransmission frame of the same RTA data and the Block Ack frame to be returned. However, if these retransmissions are not performed, the redundantly secured R-TWT SP time is wasted, so it was necessary to release the period using a CF-END (Contention Free-END) frame or the like as necessary.

[0035] Fig. 8 is a diagram showing an example of setting an uplink (UL: Uplink) R-TWT SP according to the conventional technology. Fig. 8 is written in the same way as Fig. 6, so duplicated explanations will be omitted as appropriate. In Fig. 8, the time during which predetermined RTA data can be transmitted in one R-TWT SP is indicated by a period P1 represented by a dashed line. In Fig. 8, since it is an uplink, the access point (AP) becomes a receiving communication device 10Rx, and the communication terminal (STA) becomes a transmitting communication device 10Tx, which is the opposite of the downlink.

[0036] Here, by transmitting a predetermined trigger frame (UL RTA Trigger) from the access point (AP), the communication terminal (STA) which becomes the transmitting communication device 10Tx transmits the uplink (UL) RTA data (UL RTA Data) by a predetermined access procedure, and the access point (AP) which becomes the receiving communication device 10Rx returns the receipt confirmation by a block ACK frame (BA). Here, for convenience, the redundant time including the retransmission of the R-TWT SP shown in Fig. 9 described later is shown by a period P2 indicated by a dashed line.

[0037] Fig. 9 is a diagram showing a modified example of an uplink R-TWT SP setting example according to the prior art. Fig. 9 is described in the same way as Fig. 8, so duplicated explanations will be omitted. Fig. 9 shows an example in which a single R-TWT SP is set to include redundant time for retransmission, and the time during which predetermined RTA data can be transmitted in a single R-TWT SP is shown by a period P2 indicated by a dashed line. In this setting example, the period of the R-TWT SP that is originally required is doubled so that the same amount of data can be retransmitted in a single R-TWT SP setting.

[0038] Here, by transmitting a predetermined trigger frame from an access point (AP), a communication terminal (STA) which becomes a transmitting communication device 10Tx transmits uplink RTA data (UL RTA Data) in response to this by a predetermined access procedure, and the access point (AP) which becomes a receiving communication device 10Rx returns a receipt confirmation by a block ACK frame (BA), and assuming a case where all of this RTA data does not arrive, sufficient time is secured for returning a retransmission frame and a block ACK frame of the same RTA data. However, if these retransmissions are not performed, the redundantly secured R-TWT SP time is wasted, so it was necessary to release the period by using a CF-END frame or the like as necessary.

[0039] As described above, in conventional operations, when undelivered data is retransmitted, the transmission path cannot be used efficiently, and as a result, a large delay occurs before the RTA data is output to the application device when undelivered data exists. In the operation of the present disclosure, the efficiency of the transmission path is improved when undelivered data is retransmitted. As a result, in the present disclosure, even when undelivered data exists, the delay before the RTA data is output to the application device can be suppressed. The configuration of the present disclosure will be described below.

[0040] <Operation of this disclosure> Fig. 10 is a diagram showing an example of an output sequence of an application of RTA data according to the present disclosure. In the sequence diagram of Fig. 10, similar to the sequence diagram of Fig. 5, time passes sequentially from the top to the bottom of the diagram, and shows a flow of outputting the received RTA data to the application of the receiving communication device 10Rx on the right side of the diagram when predetermined RTA data arrives almost periodically from the application of the transmitting communication device 10Tx on the left side of the diagram and data is transmitted through a wireless transmission path.

[0041] That is, the transmitting communication device 10Tx is configured to transmit RTA data collectively during the period of the R-TWT SP set almost periodically, and here, the RTA data #1 to #3 are transmitted using the first R-TWT SP. At this time, if the RTA data #3 does not arrive correctly at the receiving communication device 10Rx, the situation is returned to the transmitting communication device 10Tx via, for example, a block ACK frame (BA). Note that the receiving communication device 10Rx can set a delay amount (initial delay) for the RTA data that does not cause a delay when undelivered data occurs, and adjust the output timing to output to the application.

[0042] Here, unlike the conventional operation shown in Fig. 5, the operation of the present disclosure is configured to immediately retransmit the RTA data before retransmitting it in the R-TWT SP, outside the period of the SP in which other data is transmitted, as shown in Fig. 10. That is, when the presence of RTA data #3 is confirmed as undelivered data, the transmitting communication device 10Tx immediately retransmits the undelivered RTA data #3. Note that here, the transmitting communication device 10Tx may be configured to confirm receipt by returning a block ACK frame as necessary. The transmitting communication device 10Tx is configured to transmit the desired RTA data #4 to #7 in the next R-TWT SP.

[0043] Furthermore, here, if the RTA data #6, #7 does not arrive correctly at the receiving communication device 10Rx, the situation is returned to the transmitting communication device 10Tx via, for example, a block ACK frame. Even in this case, the RTA data is immediately retransmitted outside the period of the SP in which other data is transmitted, and for example, the RTA data #6, #7, which are undelivered data, are retransmitted.

[0044] In this case, the receiving communication device 10Rx is in a state where data up to RTA data #5 can be delivered without delay, but the undelivered RTA data #6 is also immediately retransmitted, so that data is delivered with a slight delay that has little effect on the connected application device, as shown by the arrow D2 in the figure. In other words, by making it possible for all data to be collected in the previous R-TWT SP to arrive before the next R-TWT SP arrives, the receiving communication device 10Rx can output the data to the connected application device without delay. Furthermore, the subsequent RTA data #7 is also output to the connected application device in succession, so that the output delay that once occurred is recovered over time. This provides a data retransmission method (retransmission method) suitable for real-time applications.

[0045] Fig. 11 is a diagram showing a setting example of the downlink R-TWT SP according to the present disclosure. In Fig. 11, an access point (AP) is a transmitting communication device 10Tx in the upper part shown in A of Fig. 11, and a communication terminal (STA) is a receiving communication device 10Rx in the lower part shown in B of Fig. 11, and the example is shown as a diagram in which time passes from the left side to the right side in the figure. Also, in Fig. 11A and B, a signal to be transmitted is shown as a convex upward and a signal to be received is shown as a convex downward on a time axis corresponding to the time direction, and the time of the R-TWT SP required to communicate the desired RTA data is shown by a dashed line.

[0046] That is, the time during which predetermined RTA data can be transmitted in one R-TWT SP is indicated by a period P1 indicated by a dashed line. Here, the transmitting communication device 10Tx transmits downstream RTA data (DL RTA Data) from the access point (AP) using a predetermined access procedure, and the receiving communication device 10Rx returns a receipt confirmation using a Block Ack frame (BA).

[0047] In this example, if there is undelivered data, the undelivered data is retransmitted using a timing outside the R-TWT SP period, and if necessary, a Block Ack frame (BA) is returned to confirm the presence of undelivered data again. If there is undelivered data, the data (Resend DL RTA Data) is immediately retransmitted outside the R-TWT SP period by a predetermined access procedure. Since other normal data can also be transmitted outside the R-TWT SP period, the retransmission of RTA data may be allowed or denied depending on the demand for such data.

[0048] Fig. 12 is a diagram showing an example of setting an uplink R-TWT SP according to the present disclosure. Fig. 12 is described in the same manner as Fig. 11, so duplicated explanations will be omitted as appropriate. In Fig. 12, the time during which predetermined RTA data can be transmitted in one R-TWT SP is indicated by a period P1 shown by a dashed line.

[0049] Here, a predetermined trigger frame (UL RTA Trigger) is transmitted from an access point (AP), and a communication terminal (STA) serving as a transmitting communication device 10Tx transmits uplink RTA data (UL RTA Data) using a predetermined access procedure, and the access point (AP) serving as a receiving communication device 10Rx returns a block ACK frame (BA) and a trigger frame (RT: Resend UL RTA Trigger) for retransmitting the RTA data to confirm receipt.

[0050] When the communication terminal (STA) that becomes the transmitting communication device 10Tx is requested to retransmit these RTA data, it retransmits the undelivered data at a timing outside the R-TWT SP period (Resend UL RTA Data). Furthermore, the access point (AP) that becomes the receiving communication device 10Rx returns a Block ACK frame as necessary. At this time, if there is no need for retransmission, the retransmission trigger frame (RT) is not transmitted. Also, at these timings, it is possible to transmit other normal data, resulting in a configuration that effectively utilizes the transmission path.

[0051] Fig. 13 is a diagram showing an example of a buffer configuration when transmitting RTA data using R-TWT SP. In Fig. 13, in addition to the conventional buffers for each of the main access categories (AC), a buffer for real-time applications (RTA) is provided. Alternatively, the Voice buffer, which was the conventional top-priority buffer, may be used as a buffer for RTA data, and the conventional buffer for Video data may be configured as a data buffer for Voice and Video.

[0052] <Example of wireless communication device configuration> 14 is a block diagram showing a configuration example of a wireless communication device to which the present disclosure is applied. In FIG. 14, a wireless communication device 10 includes a network module 11, an input module 12, a control module 13, an output module 14, and a wireless communication module 15.

[0053] The network module 11 performs various processes related to Internet connection under the control of the control module 13. For example, when the network module 11 operates as an access point (AP), the network module 11 is configured to implement functions such as a communication modem for connecting to the Internet network, and is configured to establish an Internet connection via a public communication line and an Internet service provider.

[0054] The input module 12 has a function of inputting instruction information corresponding to an instruction from a user to the control module 13. The input module 12 is composed of input devices such as push buttons, a keyboard, and a touch panel.

[0055] The control module 13 controls each unit (module) to operate the wireless communication device 10 as an access point (AP) or a communication terminal (STA). The control module 13 exchanges necessary information (data) with each unit (module). The control module 13 is composed of, for example, a control device such as a microprocessor or a microcontroller, a storage device such as a semiconductor memory, and the like.

[0056] The output module 14 has a function of displaying necessary information to the user based on information supplied from the control module 13. Here, information displayed or notified by the output module 14 includes, for example, the operating state of the wireless communication device 10 and information obtained via the Internet. The output module 14 is composed of output devices including, for example, display elements such as a liquid crystal display, an organic EL display, and an LED (Light Emitting Diode) display, and speakers that output voice and music.

[0057] The wireless communication module 15 performs various processes related to wireless communication under the control of the control module 13. The wireless communication module 15 is composed of, for example, a wireless communication chip, peripheral circuits, a control device such as a microcontroller, a storage device such as a semiconductor memory, etc. The details of the configuration of the wireless communication module 15 will be described later with reference to FIG.

[0058] 14, the control unit 21 is configured with the network module 11, the control module 13, and the wireless communication module 15, the input unit 22 is configured with the input module 12, and the output unit 23 is configured with the output module 14. The output unit 23 includes an application device on which a real-time application runs, and the application device is configured with a display and the like. The application device is controlled by the control unit 21. The control unit 21 may be regarded as a wireless communication device to which the present disclosure is applied. In other words, the wireless communication device to which the present disclosure is applied may be configured to include the control unit 21 and to be connected to the input unit 22 and the output unit 23.

[0059] In the wireless communication device 10, the control module 13 and the wireless communication module 15 are essential components, but the network module 11, the input module 12, and the output module 14 may be included as components, as desired. That is, each wireless communication device 10 that operates as an access point (AP) or a communication terminal (STA) may be configured with only the necessary modules, and unnecessary parts may be simplified or not included. For example, in the wireless communication device 10 of FIG. 14, the network module 11 may be included only in the access point (AP), and the input module 12 and the output module 14 may be included only in the communication terminal (STA). In the wireless communication module 15, it is optional whether an antenna is included. The wireless communication device 10 shown in FIG. 14 corresponds to both a transmitting communication device 10Tx on the data transmitting side and a receiving communication device 10Rx on the data receiving side.

[0060] Fig. 15 is a block diagram showing a configuration example of the wireless communication module 15 of Fig. 14. The wireless communication module 15 includes an interface 101 that is connected to other modules and exchanges various information and data, a transmission buffer 102 that temporarily stores data to be transmitted, an RTA data management unit 103 that manages data (RTA data) of a series of real-time applications (RTA) according to the present disclosure, and a data frame construction unit 104 that constructs a data frame (for example, an RTA data frame in Fig. 21 described later) at a predetermined timing.

[0061] The wireless communication module 15 includes a transmission opportunity control unit 105 that manages a transmission opportunity (TXOP: Transmit Opportunity) for periodically transmitting RTA data, and a control frame setting unit 106 that constructs a control frame such as a block ACK frame (for example, an RTA block ACK frame in FIG. 23 described later) and a trigger frame (for example, an RTA trigger frame in FIG. 20 described later). Furthermore, the wireless communication module 15 includes a transmission signal processing unit 107 that performs encoding processing of data to be transmitted, an access control unit 108 that performs access control required for transmitting frames, and an antenna unit 109 that transmits a transmission signal from the transmission signal processing unit 107 as a wireless signal. Here, the configuration is such that transmission control of the RTA data is performed based on the control of the access control unit 108, and the configuration is such that the state of the transmission path can be monitored and utilized successively.

[0062] Furthermore, the wireless communication module 15 includes a received signal processing unit 110 that extracts information configured as a frame from a received signal received as a wireless signal via the antenna unit 109, a control frame determination unit 111 that extracts information included in a trigger frame or a block ACK frame from each frame extracted by the received signal processing unit 110, and a data frame analysis unit 112 that extracts data such as RTA data from a received data frame. The wireless communication module 15 further includes an RTA data output timing control unit 113 that controls the timing of outputting the received RTA data to a connected application device, and a receiving buffer 114 that temporarily stores the received data.

[0063] In the configuration shown in Fig. 15, the arrows between the blocks represent the flow and control of data (signals), and each block operates in cooperation with other blocks connected by the arrows to realize its own function. For example, the RTA data management 103 operates in cooperation with the transmission opportunity control unit 105 and the RTA data output timing control unit 113 to realize the function of managing a series of RTA data according to the present disclosure. In addition, the RTA data output timing control unit 113 operates in cooperation with the RTA data management 103, the transmission opportunity control unit 105, and the data frame analysis unit 112 to realize the function of controlling the timing of outputting RTA data to an application device.

[0064] <Sequence example> Fig. 16 is a diagram showing a first example of an exchange sequence of a setup request frame for RTA data exchange. When parameters related to RTA data are exchanged from a transmitting communication device 10Tx to a receiving communication device 10Rx, the exchange sequence in Fig. 16 is used for exchanging in advance between the two wireless communication devices parameters used for notifying each other of, for example, the setting of the service period (SP) of the R-TWT and the retransmission method.

[0065] In the example of Figure 16, first, the transmitting communication device 10Tx notifies the requested parameters, and the receiving communication device 10Rx returns agreeable parameters based on the request, thereby setting the mutually agreed upon parameters for transmitting and receiving RTA data.

[0066] First, the transmitting communication device 10Tx transmits a setup request (Real Time Parameter Setup Request) for parameters related to the transmission of RTA data (S11). Then, the receiving communication device 10Rx that receives the setup request acquires the parameters described therein and returns a setup response (Real Time Parameter Response) that describes a response of parameters related to reception (S12). In this way, the setting period and duration of the service period (SP) of the R-TWT are set based on the parameters agreed upon by both communication devices, and further, an agreement is made on the operation related to the retransmission of RTA data according to the present disclosure.

[0067] Fig. 17 is a diagram showing a second example of an exchange sequence of a setup request frame for RTA data exchange. The exchange sequence of Fig. 17 is used in advance by both wireless communication devices to exchange parameters used for notifying each other of, for example, the setting of the service period (SP) of the R-TWT and the retransmission method when exchanging parameters related to RTA data from the receiving communication device 10Rx to the transmitting communication device 10Tx, in contrast to the exchange sequence of Fig. 16.

[0068] First, the receiving communication device 10Rx transmits a Real Time Parameter Setup Request for parameters related to the transmission of RTA data (S21). Then, the transmitting communication device 10Tx that receives the setup request acquires the parameters described therein and returns a Real Time Parameter Response that describes a response of parameters related to the transmission (S22). In this way, the setting period and duration of the R-TWT service period (SP) are set based on the parameters agreed upon by both communication devices, and further, an agreement is made on the operation related to the retransmission of RTA data according to the present disclosure.

[0069] <Frame composition> 18 is a diagram showing the configuration of a setup request element for access control parameters of RTA data according to the present disclosure. This setup request element is configured as a type of information element and may be exchanged, for example, at the time of association, or may be configured as a part of an action frame so that it can be exchanged at any timing.

[0070] As shown in Figure 18, the setup request element for the access control parameters of RTA data consists of an Element ID indicating the format of the element, a Length indicating the information length of the element, an RTA Access Control Setup Element consisting of the actual RTA data access control parameters, and a CRC (Cyclic Redundancy Check) which is an error detection code added if necessary.

[0071] In the setup request element, the contents of the RTA Access Control Setup Element are configured so that the requesting communication device describes and sends the desired parameters, and the responding communication device ultimately determines the parameters agreed upon.

[0072] As shown in Fig. 18, the RTA Access Control Setup Element is composed of parameters such as Reservation Type indicating a reservation setting method, TID indicating a traffic identifier for individually identifying RTA data, Reservation Start Time indicating the start time of the reservation, Reserve Duration indicating the duration of the reservation, Reserve Interval indicating the reservation interval, Buffer Size indicating the buffer size, Queue Size indicating the buffer queue size, Output Delay indicating the amount of output delay, ACK Policy indicating whether or not a block ACK needs to be returned as a method of receipt confirmation, and RTA Resend indicating a data retransmission method. The Output Delay describes the amount of delay allowed for the RTA data to the application device according to the present disclosure. The RTA Resend describes the retransmission method of the RTA data according to the present disclosure.

[0073] 19 is a diagram showing the configuration of a setup response element of the access control parameters of the RTA data according to the present disclosure. This setup response element is configured as a type of information element, and may be exchanged, for example, at the time of association, or may be configured as a part of an action frame so that it can be exchanged at any timing, and is configured to be returned as a response to the method sent as the setup request element.

[0074] As shown in Figure 19, the setup response element for the access control parameters of the RTA data consists of an Element ID indicating the format of the element, a Length indicating the information length of the element, an RTA Access Control Setup Element consisting of the actual RTA data access control parameters, and a CRC which is an error detection code added if necessary.

[0075] In the setup response element, the contents of the RTA Access Control Setup Element are configured to receive a frame containing the desired parameters from the requesting communication device, and then the responding communication device finally determines from these parameters the parameters it can support and sends them back as a response frame.

[0076] As shown in Fig. 19, the RTA Access Control Setup Element is composed of parameters such as Reservation Type indicating a reservation setting method, TID indicating a traffic identifier for individually identifying RTA data, Reservation Start Time indicating the start time of the reservation, Reserve Duration indicating the duration of the reservation, Reserve Interval indicating the reservation interval, Buffer Size indicating the size of the buffer, Queue Size indicating the queue size of the buffer, Output Delay indicating the amount of output delay, ACK Policy indicating whether or not a block ACK needs to be returned, and RTA Resend indicating a data retransmission method. The Output Delay describes the amount of delay allowed for the RTA data to the application device according to the present disclosure. The RTA Resend describes the retransmission method of the RTA data according to the present disclosure.

[0077] 20 is a diagram showing a configuration example of a trigger frame (hereinafter also referred to as an RTA trigger frame) according to the present disclosure. In the present disclosure, a trigger frame specialized for RTA data is configured to describe and transmit a retransmission method, thereby making it possible to notify, for example, a retransmission method for transmitting uplink (UL) RTA data (UL RTA Data). For example, when a transmission opportunity (TXOP) is acquired by an R-TWT SP or the like, when transmitting and receiving low-latency RTA data, the RTA trigger frame specifies, for example, an association identifier (AID) for transmission from a transmitting communication device 10Tx associated with a traffic identifier (TID) specified in the RTA data.

[0078] As shown in Figure 20, the RTA trigger frame is composed of Frame Control, which indicates a specific frame format, Duration, which indicates the duration, RA (Receive Address), which indicates receive address information, TA (Transmit Address), which indicates transmit address information, Common Info, which indicates common information for the trigger frame, User Info List, which indicates individual information for each user in the trigger frame, Padding, which is added as necessary, and FCS, which is a Frame Check Sequence for error detection.

[0079] The User Info List is configured to record User Info for each user, and the User Info is configured to include AID12 that identifies the target communication device, RU Allocation that indicates the resource unit used for communication, UL FEC Coding Type that indicates the coding format for uplink communication, UL HE-MCS, UL-DMC that indicates the coding scheme for uplink communication, SS Allocation / RA-RU Info that indicates spatial multiplexing allocation and random access resource unit, UL Target Receive Power that indicates the received power of the uplink target, etc. Reserved, which indicates a reservation for future expansion, is secured, and Trigger Dependent User Info is added as user information that depends on the trigger as necessary.

[0080] In Fig. 20, an RTA Resend that describes the retransmission method of RTA data according to the present disclosure is newly set as the configuration of User Info of the RTA trigger frame. In other words, the configuration is such that the presence or absence of retransmission of RTA data can be notified by the parameters described in RTA Resend. Fig. 20 also shows the configuration of Common Info of the RTA trigger frame.

[0081] Fig. 21 is a diagram showing a configuration example of a data frame (hereinafter also referred to as an RTA data frame) according to the present disclosure. In Fig. 21, the header information of the RTA data frame is used to notify the retransmission method of the RTA data. Specifically, as a frame configuration of an A-MPDU (Aggregate-MPDU), which is an aggregated MPDU (MAC Protocol Data Unit), information on the retransmission method of the RTA data is described in specific MPDU data.

[0082] As shown in FIG. 21, A-MPDU is configured such that multiple MPDUs are transmitted consecutively via a delimiter (D). In the present disclosure, an RTA Resend flag is set in the QoS Control portion of the MAC header of an MPDU that is a subframe constituting A-MPDU, and when the RTA Resend flag is set, the RTA MPDU following the MAC header is retransmitted. In other words, when RTA data that needs to be retransmitted is included, this bit is set, and when this bit is not set, it can be recognized that the RTA data does not need to be retransmitted. Then, in order to determine whether an error exists in this MPDU, an FCS is added to the MPDU. With this configuration, it is possible to prevent unnecessary RTA data from being retransmitted, and to use the traffic for other data transmission.

[0083] Fig. 22 is a diagram showing an example of the configuration of a delimiter of a data frame according to the present disclosure. In Fig. 22, the delimiter information of the RTA data frame is used to notify the retransmission method. Specifically, instead of or in addition to the RTA Resend information described in the MAC header shown in Fig. 21, a specific bit of the delimiter (D) of the A-MPDU is used to notify the retransmission method.

[0084] As shown in Fig. 22, an RTA Resend flag is set in the delimiter, and if the RTA Resend flag is set, the RTA data is retransmitted. In the case of a notification method using such a retransmission method using a delimiter, even if a bit error occurs in the MAC header and the FCS at the end cannot be decoded correctly, a method is obtained that can avoid the risk.

[0085] Fig. 23 is a diagram showing a configuration example of a Block ACK frame according to the present disclosure (hereinafter, also referred to as an RTA Block ACK frame). In Fig. 23, the RTA Block ACK frame has a similar configuration to maintain compatibility with a conventional Block ACK frame. As shown in Fig. 23, the RTA Block ACK frame is composed of Frame Type indicating a type of a given frame, Duration indicating the duration of the frame, RA indicating address information for identifying a receiving communication device, TA indicating address information for identifying a transmitting communication device, BA Control describing control parameters of the Block ACK frame, BA Information describing sequence number information for identifying data to be retransmitted, and FCS for frame error detection.

[0086] As shown in Fig. 23, when the RTA Resend Request bit of BA Control is set, the RTA Block ACK frame indicates that information capable of identifying (specifying) the RTA data that needs to be retransmitted is described in the following BA Information. This frame is composed of BA Information, Resend RTA Data Starting Sequence Number indicating the first sequence number for which retransmission is requested, Next Sequence Number indicating the sequence number to be transmitted in the next R-TWT SP, and Resend Request Sequence Bitmap indicating the sequence numbers that need to be retransmitted in bitmap format.

[0087] That is, when there is a time lag in the timing of outputting to the application device, the RTA data to be retransmitted can be identified and a retransmission request can be made. On the other hand, when there is no time lag in the timing of outputting to the application device, a method is obtained in which the data is treated as not requiring retransmission and unnecessary retransmission is prevented. As a result, the transmitting communication device 10Tx that has received the RTA Block ACK frame is configured to be able to identify the RTA data that needs to be retransmitted from this Block ACK frame. Note that the receiving communication device may be configured to transmit the RTA Block ACK frame when it receives a frame including a traffic identifier (TID) for retransmitting undelivered RTA data outside the period of the R-TWT SP.

[0088] <Flow of setup information exchange> The flow of the process of exchanging setup information of RTA parameters will be described with reference to the flowcharts of Figures 24 and 25. In Figures 24 and 25, the process is described as one flowchart so that both the wireless communication device 10 requesting the setup and the wireless communication device 10 responding to the setup operate.

[0089] First, both wireless communication devices 10 acquire parameters for RTA data (S101). Furthermore, both wireless communication devices 10 determine whether or not RTA data setup is required (S102), and the wireless communication device 10 that requires setup performs the subsequent steps S103 to S107. That is, the target wireless communication device 10 calculates the requested RTA parameters from the amount of information that can be transmitted per given time, information on the maximum allowable delay, the buffer capacity that can be used for RTA data, and the like (S103).

[0090] The target wireless communication device 10 also calculates an interval (Interval) of R-TWT SP that is required to be secured periodically as a transmission opportunity (TXOP) (S104), and also calculates a duration (Duration) that should be secured as a transmission opportunity (TXOP) in one R-TWT SP (S105). The target wireless communication device 10 constructs an RTA setup request frame (for example, a frame including the setup request element in FIG. 18) that describes the calculated request parameters, and transmits it to the other wireless communication device 10 (S106). Note that the target wireless communication device 10 may be configured to be able to transmit a setup request not only when it operates as a transmitting communication device 10Tx that transmits RTA data, but also when it operates as a receiving communication device 10Rx that receives RTA data.

[0091] Then, when the target wireless communication device 10 receives an RTA setup response frame (for example, a frame including the setup response element in FIG. 19) from the other wireless communication device 10 (S107: Yes), it reads out parameters that the other wireless communication device 10 can set and sets them as the agreed-upon RTA reservation parameters (S108). When the process of step S108 ends, the series of processes ends. On the other hand, if the RTA setup response frame is not received within a predetermined response time, the process returns to step S102, and the target wireless communication device 10 may review the required parameter settings again and resend the RTA setup request frame.

[0092] On the other hand, if it is determined in step S102 that a setup request will not be issued, the process proceeds to step S109 in Fig. 25. Then, if the target wireless communication device 10 receives an RTA setup request frame from the partner wireless communication device 10 (S109: Yes), it acquires the RTA parameters described in the frame (S110). The RTA parameters acquired here are the RTA parameters requested by the partner wireless communication device 10. The target wireless communication device 10 determines whether the RTA parameters can be set based on the RTA parameters acquired from the frame and its own RTA parameters (S111).

[0093] When it is determined that the RTA parameters can be set (S111: Yes), the target wireless communication device 10 performs the subsequent steps S112 to S115. That is, the target wireless communication device 10 sets an interval (Interval) of the R-TWT SP that needs to be periodically secured as a transmission opportunity (TXOP) (S112), and also sets a duration (Duration) that can be processed in one transmission opportunity (TXOP) (S113). The target wireless communication device 10 constructs an RTA setup response frame describing the set response parameters and transmits it to the other wireless communication device 10 (S114). In addition, the target wireless communication device 10 sets the parameters as the agreed-upon RTA reservation parameters (S115). When the process of step S115 ends, the series of processes ends. Note that if the RTA setup request frame is not received (S109: No), or if it is determined that the RTA parameters cannot be set (S111: No), the process ends. By exchanging this setup information, the R-TWT SP can set a service period (SP) that provides the minimum transmission opportunity (TXOP) required for RTA data.

[0094] <Flow of sending process> The flow of the transmission process by the transmitting side communication device 10Tx will be described with reference to the flowcharts of FIGS.

[0095] The transmitting communication device 10Tx judges whether or not it is within the period of the R-TWT SP in which it operates steadily (S201). When it is judged that it is within the period of the R-TWT SP (S201: Yes), and when it is judged that the transmission path is available in an idle state (S202: Yes), the transmitting communication device 10Tx performs the processes of the following steps S203 to S208.

[0096] That is, the transmitting communication device 10Tx acquires the remaining time of the R-TWT SP (S203) and acquires the RTA data (S204). The transmitting communication device 10Tx also acquires the output timing parameter of the RTA data in the receiving communication device 10Rx (S205), and when it is determined that the RTA data can be retransmitted (S206: Yes), it sets the retransmittable parameter (S207). Here, if there is enough time to perform retransmission and recover after the RTA data is transmitted even if it is not reached, it is determined that the RTA data can be retransmitted, and a flag indicating the retransmittable parameter can be set as, for example, header information. Note that when it is determined that the RTA data cannot be retransmitted (S206: No), the setting of the retransmittable parameter is skipped. Then, the transmitting communication device 10Tx transmits the RTA data frame (FIG. 21) (S208). When the process of step S208 ends, the process returns to step S201. In this way, the transmitting side communication device 10Tx can transmit the RTA data acquired at that time within the period of the R-TWT SP.

[0097] When it is determined in step S202 that the transmission path is not idle and unavailable (S202: No), the process proceeds to step S209 in FIG. 27. When the transmitting communication device 10Tx receives an RTA block ACK frame (FIG. 23) from the receiving communication device 10Rx after transmitting the RTA data frame (S209: Yes), it acquires the ACK parameter described in the frame (S210). When the transmitting communication device 10Tx refers to the ACK parameter and determines that there is no unreached data (S211: No), it exits the process and ends the series of processes. On the other hand, when it is determined that there is unreached data (S211: Yes), the subsequent processes of steps S212 to S215 are performed. The unreached data is RTA data that has not been reached among the transmitted RTA data. For example, the transmitting communication device 10Tx can determine whether there is any undelivered data by identifying data of IDs that the receiving communication device 10Rx was unable to receive from among the IDs notified in advance, or data that is missing from data that should be received continuously.

[0098] That is, the transmitting communication device 10Tx acquires an output timing parameter in the receiving communication device 10Rx for the RTA data to be retransmitted described in the ACK parameter (S212), and judges whether there is a time margin for the output timing (S213). If the transmitting communication device 10Tx judges that there is a time margin for the output timing (S213: Yes), it acquires the RTA data to be retransmitted (S214), performs a process for retransmission outside the R-TWT SP period for the acquired RTA data (S215), and transmits an RTA data frame including the RTA data to be retransmitted outside the R-TWT SP period (S208). That is, the transmitting communication device 10Tx can retransmit the undelivered RTA data during a period within a time period in which a predetermined delay is allowed (a period outside the R-TWT SP period) according to the output timing in the receiving communication device 10Rx. Note that, here, it is stated that the RTA data to be retransmitted is retransmitted outside the period of the R-TWT SP. However, it may also be understood that the end time of the R-TWT-SP that was reserved as a transmission opportunity is extended and the RTA data is retransmitted during that extended period.

[0099] On the other hand, when it is determined that there is no time to output (S213: No), the process is terminated without acquiring the RTA data to be retransmitted, and the process returns to step S201 in FIG. 26. On the other hand, when the RTA block ACK frame is not received (S209: No) and another frame is received (S216: Yes), the reception process of the other frame is performed (S217). For example, when a data frame addressed to itself is received, the reception process of the data frame is performed. That is, when the transmitting communication device 10Tx receives, for example, a trigger frame of RTA data from the receiving communication device 10Rx, which is the other party, during the R-TWT SP period, it operates to transmit RTA data in response to the request, and also operates to receive a data frame addressed to itself from another wireless communication device.

[0100] When the process of step S217 ends or when no other frame is received (S216: No), the process returns to step S201 in Fig. 26. Then, the series of operations is repeated until the R-TWT SP period continues.

[0101] <Flow of reception process> The flow of reception processing by the receiver communication device 10Rx will be described with reference to the flowcharts of FIGS.

[0102] When the receiving communication device 10Rx receives an RTA data frame addressed to itself from the transmitting communication device 10Tx (S301: Yes), it acquires the received RTA data (S302). The receiving communication device 10Rx determines whether there is a request to return an ACK frame (S303), and when it determines that it is necessary to return an ACK frame (S303: Yes), it constructs an ACK frame containing ACK parameters (S304). Furthermore, the receiving communication device 10Rx determines whether there is an error in the RTA data transmitted from the transmitting communication device 10Tx (S305), and when it determines that the RTA data contains an error (S305: Yes), it identifies the undelivered data (S306) and acquires parameters for the timing to output to the connected application device (S307).

[0103] Then, the receiving communication device 10Rx judges whether there is a time margin for the output timing (S308), and if it is judged that there is no time margin for the output timing (S308: No), the process proceeds to step S313 in FIG. 29. Alternatively, if it is judged that the RTA data does not contain an error (S305: No), the process proceeds to step S313 in FIG. 29. In this case, the receiving communication device 10Rx transmits the constructed ACK frame as a response frame as is (S313). On the other hand, if it is judged that there is a time margin for the output timing (S308: Yes), the process proceeds to step S309 in FIG. 29. That is, if there is a time margin for the output timing, the receiving communication device 10Rx judges that the RTA data can be resent, sets a resend request for the RTA data as necessary (S309), and acquires the remaining time of the R-TWT SP (S310).

[0104] The receiving communication device 10Rx judges whether the R-TWT SP period has been exceeded based on the remaining time of the R-TWT SP (S311), and when it is judged that the R-TWT SP period has been exceeded (S311: Yes), it performs processing related to retransmission outside the R-TWT SP period (S312). Then, the receiving communication device 10Rx transmits an RTA block ACK frame (FIG. 23) as a response frame (S313). For example, when undelivered data is identified and there is a grace period for the output timing, when the R-TWT SP period is exceeded (outside the R-TWT SP period), the transmitting communication device 10Tx retransmits the undelivered RTA data, so that the receiving communication device 10Rx performs processing to receive the RTA data retransmitted outside the R-TWT SP period. In addition, if the end time of the R-TWT-SP reserved as a transmission opportunity is extended and the RTA data is retransmitted, when the remaining time of the R-TWT SP is not enough to end the retransmission, the duration of the R-TWT SP is extended, the end time is extended, and an RTA Block ACK frame is transmitted as a response frame. Even if it is determined that the period of the R-TWT SP has not been exceeded (if it is determined that the extension of the R-TWT SP is not necessary), an RTA Block ACK frame is transmitted as a response frame (S313).

[0105] On the other hand, if the determination in step S301 is that the RTA data frame has not been received (S301: No), the process proceeds to step S314 in Fig. 29. The receiving communication device 10Rx determines whether the R-TWT SP period range has been exceeded (S314), and if it is determined that the R-TWT SP period range has been exceeded (S314: Yes), and if it is determined that there is undelivered RTA data (S315: Yes), the process returns to step S301 and continues the RTA data reception process. Note that, for example, when the receiving communication device 10Rx operates as an access point (AP) and operates as a transmission opportunity (TXOP) holder of the R-TWT SP, it may transmit a trigger frame as necessary to prompt the transmitting communication device 10Tx to transmit RTA data addressed to itself, and then operate to receive the RTA data.

[0106] Alternatively, if it is determined in step S314 that the period range of the R-TWT SP has not been exceeded (S314: No), the process returns to step S301 and waits for reception of a series of RTA data. On the other hand, if it is determined that the period range of the R-TWT SP has been exceeded (S314: Yes), and there is no more RTA data that has not been received (S315: No), or if it is determined that there is no need to return an ACK frame (S303: No), the process of receiving the RTA data in the target R-TWT SP is terminated.

[0107] As described above, the transmitting communication device 10Tx of the present disclosure, under the control of the control unit 21 of FIG. 14, transmits data (for example, RTA data such as the RTA data frame of FIG. 21) to the receiving communication device 10Rx, receives retransmission request information (for example, the RTA block ACK frame of FIG. 23) transmitted from the receiving communication device 10Rx, and can retransmit, to the receiving communication device 10Rx, undelivered data identified by the received retransmission request information and which is among the transmitted data and which has not been delivered, according to the output timing at which data is output to an application device connected to the receiving communication device 10Rx (an application device included in the output unit 23 of FIG. 14).

[0108] In addition, the receiving communication device 10Rx of the present disclosure, under the control of the control unit 21 in FIG. 14, can receive data (for example, RTA data such as the RTA data frame in FIG. 21) transmitted from the transmitting communication device 10Tx, adjust the output timing of outputting the received data to a connected application device (an application device included in the output unit 23 in FIG. 14), generate retransmission request information (for example, the RTA block ACK frame in FIG. 23) requesting retransmission of undelivered data, which is data that has not been delivered among the transmitted data, according to the output timing, and transmit the generated retransmission request information to the transmitting communication device 10Tx.

[0109] That is, in the present disclosure, the receiver communication device 10Rx determines whether or not to retransmit the undelivered data according to the output timing of outputting the RTA data to the application device connected thereto, and retransmits the undelivered data at a timing when retransmission is possible, thereby improving the utilization efficiency of the transmission path. As a result, even when undelivered data exists, the receiver communication device 10Rx can suppress the delay until the RTA data is output to the application device.

[0110] In addition, in the present disclosure, since the retransmission data is retransmitted in a period (a second period different from the first period) different from the predetermined service period of the transmission opportunity, that is, outside the period of the set R-TWT SP, the minimum required R-TWT SP can be set and reused for other data transmission. Furthermore, since the receiving communication device 10Rx manages the return of the ACK frame and the return request, the receiving communication device 10Rx can adaptively determine whether or not retransmission is necessary depending on the margin of the output timing. By adjusting the output timing of the RTA data received by the receiving communication device 10Rx to the application device, even if a delay occurs due to retransmission, it is possible to recover appropriately.

[0111] As mentioned above, the R-TWT technology is defined as a technology that realizes low power consumption operation by determining the time to activate a conventional target and activating it, and is defined as a mechanism in which a transmitting communication device periodically acquires a transmission opportunity (TXOP) and transmits data that should be transmitted with low latency during the transmission opportunity (TXOP) with priority over other data. In other words, a technology has been proposed in which a traffic identifier (TID) linked to the transmitting communication device and the receiving communication device is defined, and when a transmission opportunity (TXOP) arrives at a predetermined period, only data with this identifier is transmitted with priority. The R-TWT technology is considered to be a promising method for transmitting data suitable for real-time applications, and technical proposals using these methods are currently being made.

[0112] These R-TWT technologies are defined so that the transmitting and receiving communication devices operate in sync at a certain period, but in order to specify a certain period and prioritize these communications, it was necessary to set the R-TWT service period (SP). When applying these technologies to RTA data, which requires low latency, it is necessary to set parameters to complete transmission within the allowable delay time, and there was a problem that transmission delays would occur unless the arrival period of the R-TWT SP was shortened. In addition, since communication errors occur on the wireless transmission path, there was a problem that all data could not be delivered reliably end-to-end unless the data with these errors was resent. In particular, if the communication volume required for the minimum required data transmission was secured by securing one transmission opportunity (TXOP) of the R-TWT SP, it was impossible to resend the undelivered data within the service period.

[0113] As currently assumed, if the transmission of RTA data (data that requires low delay) is limited to the R-TWT SP, there is a problem that the transmission of RTA data is delayed unless the next R-TWT SP arrives, and the delay accumulates. In other words, if undelivered data accumulates and data is retransmitted to resolve this, the amount of delay in the transmission of RTA data tends to increase, which is not desirable. Therefore, in order to secure a transmission opportunity (TXOP) in the R-TWT SP and retransmit data that has not been delivered due to a transmission error, it is necessary to secure a service period (SP) including redundant time. However, in this case, there is a problem that the service period (SP) is set for a specific wireless communication, and the transmission opportunity (TXOP) for other general wireless communication is relatively reduced. In particular, when retransmission is not necessary, it is necessary to release the redundant time secured as the service period (SP) and reuse it for other general data communication.

[0114] Therefore, in this disclosure, as a method for solving such a problem, the following wireless communication device and wireless communication method are proposed. That is, in a receiving communication device, when there is a margin in the output timing of the RTA data, a wireless communication device and a wireless communication method are proposed that retransmit undelivered data to reliably collect and output data with a low delay. In addition, in this disclosure, when it is difficult to transmit RTA data within an R-TWT period scheduled to acquire a transmission opportunity (TXOP) at a predetermined cycle, a wireless communication device and a wireless communication method are proposed that retransmit RTA data with a low delay beyond the range of the period. Furthermore, in this disclosure, a wireless communication device and a wireless communication method are proposed that output received RTA data so as not to cause a delay from the predetermined output timing of the RTA data.

[0115] Such a wireless communication device and wireless communication method can provide the following effects, for example. That is, by determining whether or not to retransmit the RTA data according to the output timing of the receiving communication device, it is possible to reduce traffic involved in retransmitting unnecessary data and improve the utilization efficiency of the transmission path. By managing the output timing in the transmitting communication device as well, it is possible to deliver the RTA data to an application device connected to the receiving communication device with little delay.

[0116] In the receiving communication device, when there is a margin in the output timing, a block ACK frame for a retransmission request is returned, thereby refraining from retransmitting unnecessary RTA data. In the receiving communication device, when there is no margin in the output timing, a method for efficiently using the transmission path is obtained by not requesting retransmission. Even if undelivered data occurs in the RTA data, delays can be recovered by adjusting the output timing of the receiving communication device by retransmitting at any timing. The transmitting communication device can deliver the RTA data to the receiving communication device with low delay by retransmitting the RTA data beyond the service period of the R-TWT SP. In addition, the transmitting communication device only needs to set the service period of the R-TWT SP to a minimum for the desired RTA data between the transmitting communication device and the receiving communication device, and can also use communication of other general data, thereby improving the utilization efficiency of the transmission path.

[0117] <Modification> The above-mentioned series of processes can be executed by hardware or software. When the series of processes is executed by software, a program constituting the software is installed from a program recording medium into a computer built into dedicated hardware or a general-purpose PC (Personal Computer). For example, in a computer that executes the above-mentioned series of processes by a program, a CPU (Central Processing Unit) loads a program stored in a storage unit consisting of a hard disk or non-volatile memory into a RAM (Random Access Memory) and executes the program, thereby executing the above-mentioned series of processes. Note that the program executed by the computer may be a program that is processed in chronological order according to the sequence described in this specification, or may be a program that is processed in parallel or at a required timing such as when it is called.

[0118] The present disclosure is applicable to various products. For example, when the wireless communication device 10 is a communication terminal (STA), it may be configured as a mobile terminal such as a smartphone, a tablet PC, a notebook PC, a portable game terminal, or a digital camera, a fixed terminal such as a television receiver, a printer, a digital scanner, or a network storage, or an in-vehicle terminal such as a car navigation device. The wireless communication device 10 may also be configured as an M2M (Machine To Machine Communication) terminal such as a smart meter, a vending machine, a remote monitoring device, or a POS (Point Of Sale) terminal. Furthermore, the wireless communication device 10 may be a wireless communication module (for example, an integrated circuit module configured on one die) mounted on these terminals.

[0119] Also, for example, when the wireless communication device 10 is an access point (AP), it may be configured as a wireless LAN AP (wireless base station) with or without a router function. Also, the wireless communication device 10 may be configured as a mobile wireless LAN router. Furthermore, the wireless communication device 10 may be a wireless communication module (for example, an integrated circuit module configured on a single die) mounted on these devices.

[0120] The embodiments of the present disclosure are not limited to the above-described embodiments, and various modifications are possible without departing from the scope of the present disclosure. Furthermore, the effects described in this specification are merely examples and are not limiting, and other effects may be obtained.

[0121] The present disclosure can also be configured as follows.

[0122] (1) Receive data transmitted from another wireless communication device; Adjusting an output timing for outputting the received data to a connected application device; generating retransmission request information for requesting retransmission of undelivered data, which is the data that has not been delivered among the transmitted data, in accordance with the output timing; The generated retransmission request information is transmitted to the other wireless communication device. Equipped with a control unit that controls Wireless communication device. (2) The control unit is receiving the data transmitted from the other wireless communication device during a first period of a transmission opportunity determined in advance between the other wireless communication device and the other wireless communication device; receiving the undelivered data transmitted from the other wireless communication device that has received the retransmission request information during a second period different from the first period; The wireless communication device according to (1). (3) The control unit is generating a response frame including the retransmission request information for identifying the undelivered data when there is sufficient time to output the data to the application device; The response frame is transmitted to the other wireless communication device. The wireless communication device according to (2). (4) The control unit generates the response frame not including the retransmission request information when there is no time to output the data to the application device. The wireless communication device according to (3). (5) When the control unit receives a frame including a traffic identifier for performing retransmission of the undelivered data during the second period, the control unit transmits the response frame to the other wireless communication device. The wireless communication device according to (3) or (4). (6) When the control unit retransmits the undelivered data during the second period, the control unit transmits the response frame to the other wireless communication device. The wireless communication device according to (3) or (4). (7) The control unit transmits a first trigger frame related to the transmission of the data to the other wireless communication device when the first period arrives. A wireless communication device according to any one of (2) to (4). (8) When the control unit retransmits the undelivered data during the second period, the control unit transmits a second trigger frame regarding the retransmission of the undelivered data to the other wireless communication device. The wireless communication device according to (7). (9) The control unit sets a delay amount for the data such that no delay occurs when the undelivered data occurs, and adjusts the output timing to output the data to the application device. A wireless communication device according to any one of (1) to (8). (10) A wireless communication device, Receive data transmitted from another wireless communication device; Adjusting an output timing for outputting the received data to a connected application device; generating retransmission request information for requesting retransmission of undelivered data, which is the data that has not been delivered among the transmitted data, in accordance with the output timing; The generated retransmission request information is transmitted to the other wireless communication device. A wireless communication method. (11) Transmitting the data to another wireless communication device; receiving retransmission request information transmitted from the other wireless communication device; In response to an output timing of outputting the data to an application device connected to the other wireless communication device, the undelivered data specified by the received retransmission request information and which has become undelivered among the transmitted data is retransmitted to the other wireless communication device. Equipped with a control unit that controls Wireless communication device. (12) The control unit is transmitting the data to the other wireless communication device during a first period of a transmission opportunity predetermined between the other wireless communication device and the other wireless communication device; retransmitting the undelivered data to the other wireless communication device during a second period different from the first period. The wireless communication device according to (11). (13) The control unit is receiving a response frame transmitted from the other wireless communication device; The data that has not been delivered within the first period is identified according to the retransmission request information included in the received response frame. The wireless communication device according to (12). (14) The control unit retransmits the undelivered data to the other wireless communication device during the second period within a time period in which a predetermined delay is allowed, according to the output timing. The wireless communication device according to (12) or (13). (15) The control unit sets, as the first period, a service period that provides a minimum necessary transmission opportunity for the data. The wireless communication device according to (12) or (13). (16) When the control unit acquires the transmission opportunity, the control unit transmits the data currently acquired within the first period to the other wireless communication device. The wireless communication device according to (12). (17) The control unit transmits to the other wireless communication device a frame including a traffic identifier for performing retransmission of the undelivered data during the second period. The wireless communication device according to (12). (18) When the control unit receives a first trigger frame related to transmission of the data from the other wireless communication device, the control unit transmits the data to the other wireless communication device. A wireless communication device according to any one of (12) to (16). (19) When the control unit receives a second trigger frame related to retransmission of the undelivered data from the other wireless communication device, the control unit retransmits the undelivered data to the other wireless communication device. The wireless communication device according to (18). (20) A wireless communication device, Transmitting the data to another wireless communication device; receiving retransmission request information transmitted from the other wireless communication device; In response to an output timing of outputting the data to an application device connected to the other wireless communication device, the undelivered data specified by the received retransmission request information and which has become undelivered among the transmitted data is retransmitted to the other wireless communication device. A wireless communication method. [Explanation of symbols]

[0123] 10 wireless communication device, 10Tx transmitting communication device, 10Rx receiving communication device, 11 network module, 12 input module, 13 control module, 14 output module, 15 wireless communication module, 21 control section, 22 input section, 23 output section, 101 interface, 102 transmission buffer, 103 RTA data management section, 104 data frame construction section, 105 transmission opportunity control section, 106 control frame setting section, 107 transmission signal processing section, 108 access control section, 109 antenna section, 110 reception signal processing section, 111 control frame determination section, 112 data frame analysis section, 113 RTA data output timing control section, 114 reception buffer

Claims

1. Receive data transmitted from another wireless communication device; Adjusting an output timing for outputting the received data to a connected application device; generating retransmission request information for requesting retransmission of undelivered data, which is the data that has not been delivered among the transmitted data, in accordance with the output timing; The generated retransmission request information is transmitted to the other wireless communication device. Equipped with a control unit that controls Wireless communication device.

2. The control unit is receiving the data transmitted from the other wireless communication device during a first period of a transmission opportunity determined in advance between the other wireless communication device and the other wireless communication device; receiving the undelivered data transmitted from the other wireless communication device that has received the retransmission request information during a second period different from the first period; The wireless communication device of claim 1 .

3. The control unit is generating a response frame including the retransmission request information for identifying the undelivered data when there is sufficient time to output the data to the application device; The response frame is transmitted to the other wireless communication device. The wireless communication device according to claim 2 .

4. The control unit generates the response frame not including the retransmission request information when there is no time to output the data to the application device. The wireless communication device according to claim 3 .

5. When the control unit receives a frame including a traffic identifier for performing retransmission of the undelivered data during the second period, the control unit transmits the response frame to the other wireless communication device. The wireless communication device according to claim 3 .

6. When the control unit retransmits the undelivered data during the second period, the control unit transmits the response frame to the other wireless communication device. The wireless communication device according to claim 3 .

7. The control unit transmits a first trigger frame related to the transmission of the data to the other wireless communication device when the first period arrives. The wireless communication device according to claim 2 .

8. When the control unit retransmits the undelivered data during the second period, the control unit transmits a second trigger frame regarding the retransmission of the undelivered data to the other wireless communication device.

8. The wireless communication device according to claim 7.

9. The control unit sets a delay amount for the data such that no delay occurs when the undelivered data occurs, and adjusts the output timing to output the data to the application device. The wireless communication device of claim 1 .

10. A wireless communication device, Receive data transmitted from another wireless communication device; Adjusting an output timing for outputting the received data to a connected application device; generating retransmission request information for requesting retransmission of undelivered data, which is the data that has not been delivered among the transmitted data, in accordance with the output timing; The generated retransmission request information is transmitted to the other wireless communication device. A wireless communication method.

11. Transmitting the data to another wireless communication device; receiving retransmission request information transmitted from the other wireless communication device; In response to an output timing of outputting the data to an application device connected to the other wireless communication device, the undelivered data specified by the received retransmission request information and which has become undelivered among the transmitted data is retransmitted to the other wireless communication device. Equipped with a control unit that controls Wireless communication device.

12. The control unit is transmitting the data to the other wireless communication device during a first period of a transmission opportunity that is predetermined between the other wireless communication device and the other wireless communication device; retransmitting the undelivered data to the other wireless communication device during a second period different from the first period.

12. The wireless communication device of claim 11.

13. The control unit is receiving a response frame transmitted from the other wireless communication device; The data that has not arrived within the first period is identified according to the retransmission request information included in the received response frame.

13. The wireless communication device of claim 12.

14. The control unit retransmits the undelivered data to the other wireless communication device during the second period within a time period in which a predetermined delay is allowed, according to the output timing.

13. The wireless communication device of claim 12.

15. The control unit sets, as the first period, a service period that provides a minimum necessary transmission opportunity for the data.

13. The wireless communication device of claim 12.

16. When the control unit acquires the transmission opportunity, the control unit transmits the data currently acquired within the first period to the other wireless communication device.

13. The wireless communication device of claim 12.

17. The control unit transmits to the other wireless communication device a frame including a traffic identifier for performing retransmission of the undelivered data during the second period.

13. The wireless communication device of claim 12.

18. When the control unit receives a first trigger frame related to transmission of the data from the other wireless communication device, the control unit transmits the data to the other wireless communication device.

13. The wireless communication device of claim 12.

19. When the control unit receives a second trigger frame related to retransmission of the undelivered data from the other wireless communication device, the control unit retransmits the undelivered data to the other wireless communication device.

20. The wireless communication device of claim 18.

20. A wireless communication device, Transmitting the data to another wireless communication device; receiving retransmission request information transmitted from the other wireless communication device; In response to an output timing of outputting the data to an application device connected to the other wireless communication device, the undelivered data specified by the received retransmission request information and which has become undelivered among the transmitted data is retransmitted to the other wireless communication device. A wireless communication method.

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