Communication device, communication device control method, and program

Abstract

To perform notification of parameters for executing TXOP sharing between multiple devices.SOLUTION: A communication device capable of wireless communication compliant with the IEEE802.11 series of standards transmits to another communication device, during the TXOP period reserved by the communication device, a wireless frame for executing TXOP sharing among multiple devices, which transfers a transmission opportunity (TXOP) reserved by the communication device to another communication device to reserve a TXOP sharing period, and a trigger frame for transferring the TXOP to another communication device, and the wireless frame includes at least one of predetermined information capable of identifying the maximum duration of the TXOP sharing period and information indicating that the TXOP sharing period is to be placed after the TXOP period reserved by the communication device.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a communication device that performs wireless communication, a control method for the communication device, and a program. [Background technology]

[0002] The Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards is known as a communication standard for wireless local area networks (LANs). The IEEE 802.11 series of standards includes IEEE 802.11a / b / g / n / ac / ax / be, etc. The IEEE 802.11be standard and its successors aim to improve communication efficiency and throughput and reduce latency by having multiple access point devices (hereinafter simply referred to as APs) operate cooperatively.

[0003] In particular, methods to improve communication efficiency and reliability are being discussed for the 11bn or Ultra High Reliability (UHR) standard, which is being considered as the successor to 11be. One proposed method for improving efficiency and reliability is C-TDMA, which allows an AP that has secured a TXOP (Sharing AP) to transfer the TXOP to another AP (Shared AP) (TXOP Sharing), enabling communication between the Shared AP and STAs. Furthermore, a method for cooperative TXOP sharing among multiple APs has been proposed to prevent STAs connected to the Shared AP from intercepting TXOP Sharing communications and setting a No Communication Available (NAV). TXOP sharing among multiple APs is also known as Provisional TXOP. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-50133 Summary of the Invention [Problem to be solved by the invention]

[0005] As mentioned above, securing Provisional TXOP is one method to improve efficiency and reliability. However, there is no standard for notifying the wireless communication device of the parameters used when executing Provisional TXOP, which makes it difficult to use.

[0006] In view of the above problems, an object of the present invention is to provide a technique for notifying parameters for executing TXOP sharing among multiple devices. [Means for solving the problem]

[0007] In order to achieve the above object, a communication device of the present invention is a communication device capable of wireless communication conforming to the IEEE 802.11 series of standards, a radio frame for executing TXOP sharing among a plurality of devices, which transfers a transmission opportunity (TXOP) secured by the communication device to another communication device and secures a TXOP sharing period; a trigger frame that grants a TXOP to another communication device; a transmitting means for transmitting the above to the other communication device during the TXOP period secured by the communication device, The radio frame is characterized by including at least one of predetermined information that can identify the maximum duration of the TXOP Sharing period and information indicating that the TXOP Sharing period will be placed after the TXOP period reserved by the communication device. [Effects of the Invention]

[0008] According to one aspect of the present invention, a technique for notifying parameters for executing TXOP sharing among multiple devices can be provided. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a configuration of a wireless communication system according to an embodiment of the present invention; [Figure 2] FIG. 1 is a diagram showing a hardware configuration of a wireless communication device according to an embodiment of the present invention; [Figure 3] FIG. 1 is a diagram showing the functional configuration of a wireless communication device according to an embodiment of the present invention; [Figure 4] FIG. 10 is a diagram illustrating an example of a MAC frame. [Figure 5] FIG. 10 is a diagram showing an example of an Action frame used to notify parameters related to Provisional TXOP. [Figure 6] FIG. 1 is a diagram showing an example of an operation sequence according to the first embodiment executed by a Sharing AP, a Shared AP, and a STA connected to the Sharing AP. [Figure 7] A diagram showing an example of processing executed by the Sharing AP. [Figure 8] A diagram showing an example of processing executed by a Shared AP [Figure 9] FIG. 10 illustrates a modified example of an Action frame used to notify parameters related to Provisional TXOP. [Figure 10] Figure 10 shows an example of an Action frame for notifying TXOP return during Provisional TXOP operation. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0011] (Wireless communication system configuration) 1 shows the configuration of a wireless communication system according to this embodiment. The wireless communication system 1 includes an access point device (hereinafter simply referred to as an AP or access point) 103 that establishes a wireless communication network 10, and station devices (hereinafter simply referred to as STAs or stations) 106 that serve as participant devices. An AP 104 establishes a wireless communication network (not shown), and a STA 105 participates in the wireless communication network established by the AP 104. A range 20 indicates the reachable range of wireless frames transmitted by the AP 103.

[0012] The APs 103 and 104 and the STAs 105 and 106 are configured to perform wireless communication compliant with the IEEE802.11bn standard, which is the successor to the IEEE802.11be standard and targets a maximum transmission speed of 46.08 Gbps. IEEE stands for Institute of Electrical and Electronics Engineers.

[0013] The main features of IEEE802.11bn are high-reliability communication, low-latency communication, and improved throughput during congestion. Wireless frames communicated under this successor standard are also called UHR (Ultra High Reliability) PPDUs. PPDU stands for PLCP Protocol Data Unit, and PLCP stands for Physical Layer Convergence Protocol.

[0014] The names IEEE802.11bn and UHR standard were chosen for convenience, taking into account the goals and key features of the successor standards, and may be different names once the standards are fully established. However, please note that this specification and the accompanying claims are essentially successor standards to the IEEE802.11be standard and are applicable to all successor standards.

[0015] While the wireless communication system 1 shown in FIG. 1 is described as being configured with one AP and one STA, the number of APs and STAs is not limited to this. For example, the system may include two or more STAs. In this case, the frequency band and bandwidth of the established link may be changed. Furthermore, while the APs 103, 104, and the STAs 105, 106 are described as being compatible with UHR PPDU communication of the IEEE 802.11bn standard, this is not a limitation. Additionally, the APs 103, 104, and the STAs 105, 106 may be compatible with IEEE 802.11 standards that predate the IEEE 802.11bn standard. Specifically, the APs 103, 104, and the STAs 105, 106 may be configured to be compatible with PPDU communication of the IEEE 802.11a / b / g / n / ac / ax / be standards, etc.

[0016] Furthermore, the APs 103, 104 and the STAs 105, 106 may support other communication standards such as Bluetooth (registered trademark), NFC, UWB, ZigBee, MBOA, etc. in addition to the IEEE802.11 standard series. UWB stands for Ultra Wide Band, and MBOA stands for Multi-Band OFDM Alliance. NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, WiNET, etc. They may also support communication standards for wired communication such as a wired local area network (LAN).

[0017] Specific examples of the APs 103 and 104 and the STAs 105 and 106 include, but are not limited to, wireless LAN routers and personal computers (PCs). The APs 103 and 104 and the STAs 105 and 106 may also be wireless communication devices such as wireless chips capable of performing wireless communication conforming to the IEEE 802.11bn standard. Specific examples of the STAs 105 and 106 include, but are not limited to, cameras, tablets, smartphones, PCs, mobile phones, video cameras, and headsets. The STAs 105 and 106 may also be wireless communication devices such as wireless chips capable of performing wireless communication conforming to the IEEE 802.11bn standard.

[0018] The APs 103 and 104 and the STAs 105 and 106 can communicate in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. The frequency bands used by each communication device are not limited to these, and a different frequency band, such as the 60 GHz band, may be used. The APs 103 and 104 can also operate in any of several bandwidths, such as 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, and 640 MHz.

[0019] (Configuration of wireless communication device) 2 shows an example of the hardware configuration of a wireless communication device (AP and STA). As an example, the wireless communication device has a storage unit 201, a control unit 202, a function unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207. Note that the number of antennas may be one or more.

[0020] The storage unit 201 is configured with one or more memories such as a read-only memory (ROM) or a random access memory (RAM), and stores various information such as computer programs for performing various operations described below and communication parameters for wireless communication. Note that, in addition to memories such as ROM and RAM, storage media such as a flexible disk, a hard disk, or an SSD (Solid State Drive) may be used as the storage unit 201. Alternatively, in addition to memories such as ROM and RAM, storage media such as an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, or a DVD may be used as the storage unit 201. Furthermore, the storage unit 201 may include multiple memories.

[0021] The control unit 202 is configured with one or more processors, such as a central processing unit (CPU) or a microprocessing unit (MPU), and controls the entire AP 103 by executing a computer program stored in the storage unit 201. The control unit 202 may also control the entire AP 103 in cooperation with the computer program stored in the storage unit 201 and an OS (Operating System). The control unit 202 also generates data and signals (wireless frames) to be transmitted in communications with other wireless communication devices. The CPU stands for Central Processing Unit, and the MPU stands for Micro Processing Unit. The control unit 202 may also be equipped with multiple processors, such as multi-core processors, and the multiple processors may control the entire wireless communication device.

[0022] Furthermore, the control unit 202 controls the function unit 203 to perform predetermined processes such as wireless communication, imaging, printing, projection, etc. The function unit 203 is hardware that enables the communication device to perform predetermined processes.

[0023] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user via a monitor screen or a speaker. Here, the output from the output unit 205 may be a display on a monitor screen, an audio output from a speaker, a vibration output, or the like. Note that both the input unit 204 and the output unit 205 may be implemented in a single module, such as a touch panel. Furthermore, the input unit 204 and the output unit 205 may be integrated with the wireless communication device, or may be separate units.

[0024] The communication unit 206 controls wireless communication conforming to the IEEE802.11bn standard. The communication unit 206 may also control wireless communication conforming to other IEEE802.11 series standards in addition to the IEEE802.11bn standard, and control wired communication such as a wired LAN. The communication unit 206 controls the antenna 207 to transmit and receive signals generated by the control unit 202 for wireless communication.

[0025] If the wireless communication device supports the NFC standard, Bluetooth standard, or the like in addition to the IEEE802.11bn standard, it may control wireless communication in accordance with these communication standards. If the wireless communication device can perform wireless communication in accordance with multiple communication standards, it may be configured with separate communication units and antennas corresponding to each communication standard. The wireless communication device communicates data such as image data, document data, and video data with other communication devices via the communication unit 206. The antenna 207 may be configured separately from the communication unit 206, or may be configured together with the communication unit 206 as a single module.

[0026] Antenna 207 is an antenna capable of communication in the 2.4 GHz band, 5 GHz band, and 6 GHz band. A communication device may have one or more antennas. Also, a different antenna may be provided for each frequency band. Furthermore, if AP 103 or AP 104 has multiple antennas, it may have a communication unit 206 corresponding to each antenna.

[0027] <Functional configuration of wireless communication device> Next, the functional configuration of the wireless communication device (APs 103, 104, STAs 105, 106) will be described with reference to Fig. 3. Fig. 3 is a block diagram showing the functional configuration of the wireless communication device in this embodiment.

[0028] The wireless communication device includes a wireless LAN control unit 301 , a frame generation unit 302 , a frame analysis unit 303 , a UI control unit 304 , and a storage unit 305 .

[0029] The wireless LAN control unit 301 controls the communication unit 206 and antenna 207 for transmitting and receiving wireless signals to and from other wireless communication devices. Specifically, the wireless LAN control unit 301 cooperates with the frame generation unit 302 and frame analysis unit 303 to execute communication control of wireless frames in accordance with the IEEE802.11 series standards.

[0030] The frame generation unit 302 generates a wireless control frame to be transmitted by the wireless LAN control unit 301. The wireless frame includes a preamble field and a data field. The data field stores MAC frames such as management frames, control frames, and data frames. The contents of the wireless control generated by the frame generation unit 302 may be restricted by settings stored in the storage unit 305. They may also be changed by user settings from the UI control unit 304.

[0031] Information about the generated frame is sent to wireless LAN control unit 301, and transmitted to the outside via communication unit 206 and antenna 207. Information about the frame received by communication unit 206, antenna 207, and wireless LAN control unit 301 working together is passed to frame analysis unit 303 for analysis. When analysis is performed by frame analysis unit 303, the analysis method may be determined based on settings stored in storage unit 305.

[0032] The UI control unit 304 includes hardware related to a user interface, such as a touch panel or buttons for receiving user operations from the AP to the STA (not shown), and a program for controlling these. The UI control unit 304 also has a function for presenting information, such as displaying images or outputting audio, to the user.

[0033] The storage unit 305 is a storage device that can be configured with a ROM, a RAM, etc., for storing programs and data that the wireless communication device operates on.

[0034] (Example) 4 shows an example of the format of a MAC header according to this embodiment. The MAC header begins with Frame Control 401, followed by fields such as Duration / ID 402 and Address 1. The fields after Address 1 conform to the conventional IEEE 802.11 standard, and therefore a description thereof will be omitted. Frame Control 401 further comprises several subfields, followed by fields such as Protocol Version 411, Type 412, SubType 413, and ToDS 414, in that order from the beginning. The fields after ToDS conform to the conventional IEEE 802.11 standard, and therefore a description thereof will be omitted.

[0035] The type of frame can be indicated by storing predetermined values ​​in Type 412 and SubType 413 included in the Frame Control 401 field. For example, storing the value "0" in Type 412 and the value "13" in SubType 413 can indicate that the MAC frame is an Action frame.

[0036] An example of the Frame Body of an Action frame transmitted by the wireless communication device according to this embodiment is shown in Fig. 5. As shown in Fig. 5, the Action field 500 is broadly composed of a Category field 501 and an Action Details field 502. The Action field 500 is included in the Frame Body field shown in the MAC header format in Fig. 4.

[0037] A value indicating the use of the Action frame is stored in the Category field 501. Here, the value "38" is stored to indicate that the Action frame is used for Cooperative Time Division Multiple Access (C-TDMA).

[0038] The Action Details field 502 includes a field for indicating specific information about the use of the Action frame specified in the Category field 501. At the beginning of the Action Details field 502, there is a C-TDMA Action field 511 that indicates the specific type of operation among the C-TDMA operations. Here, the value "0" is stored to indicate that a Provisional TXOP notification operation is being performed among the C-TDMA operations. Here, Provisional TXOP is a communication method in which a wireless communication device having a transmission opportunity (TXOP) transfers the transmission opportunity to another wireless communication device to share the TXOP among multiple devices. For example, Provisional TXOP is information shared between a Sharing AP and a Shared AP, and prevents a non-AP STA from setting a NAV and thus preventing the Shared AP and the non-AP STA from being unable to communicate. In this way, Provisional TXOP is recognized between the Sharing AP and the Shared AP. For example, even if a Provisional TXOP notification arrives at a non-AP STA under the shared AP, the NAV is not set, unlike a normal TXOP. In this embodiment, a wireless communication device having a TXOP notifies other wireless communication devices that it will execute a Provisional TXOP within the TXOP period. Furthermore, as an example of a parameter for executing the Provisional TXOP, the maximum length of the TXOP period (TXOP Sharing period) transferred to the other wireless communication devices is notified. Furthermore, by including an identifier of the wireless communication device that shares the TXOP in a predetermined field such as the Address field or ToDS field of the MAC header, the Shared AP can identify that the TXOP is being shared.

[0039] Following the C-TDMA Action field 511 is a Provisional TXOP notification element 512, which is an information element (IE) indicating information related to the notification of Provisional TXOP.

[0040] As shown in FIG. 5C, the Provisional TXOP notification element 512 is composed of, from the beginning, the fields of Element ID 521, Length 522, Element ID Extension 523, Provisional TXOP Start time 524, and Provisional TXOP Limit 525.

[0041] Length 522 stores the length of the Provisional TXOP notification element 512. Furthermore, Element ID 521 and Element ID Extension 523 store values ​​for indicating that the IE included in the Action frame is this Provisional TXOP notification element. For example, the value "255" may be stored in Element ID 521 and the value "160" may be stored in Element ID Extension 523 to indicate that it is a Provisional TXOP notification element, but this is not limitative.

[0042] Provisional TXOP Start time 524 stores the start time (start timing) of the Provisional TXOP.

[0043] The start time of the Provisional TXOP period can be defined in the following three patterns. In the first pattern, the start time of the Provisional TXOP period is the time when a wireless communication device operating as a Sharing TXOP that shares a TXOP secures the TXOP. In the first pattern, the start time of the Provisional TXOP period is the start time of a period 606, which will be described later with reference to FIG. 6. In this case, Provisional TXOP Start time 524 is set to 0 or is omitted.

[0044] In the second pattern, the start time of the Provisional TXOP period is set to the time when Sharing TXOP transmits a notification of parameters for executing Provisional TXOP. In the second pattern, the start time of the Provisional TXOP period is set to the transmission time of a Provisional TXOP notification frame 602, which will be described later with reference to FIG. 6. In this case, the start time of the Provisional TXOP period can be set to the transmission timing of a frame including a Provisional TXOP notification element 512. The frame transmission timing can be set in microseconds as an offset value from the start time of the currently reserved TXOP. Alternatively, the value of the TSF (Time Synchronization Function) timer at the start time of the Provisional TXOP can be set in units of one time unit (TU), i.e., 32 microseconds.

[0045] In the third pattern, the start time of the Provisional TXOP period is determined to be the timing when the Sharing TXOP transmits a trigger frame to transfer the TXOP or the timing when a response to the trigger frame is received. The trigger frame may be, for example, an MU-RTS (Multi-User Request To Send) TXS (TXOP Sharing) frame, and the response to the trigger frame may be a CTS (Clear To Send) signal. In the third pattern, the start time of the Provisional TXOP period is determined to be the timing when the MU-RTS TXS 603, described later with reference to FIG. 6, is transmitted or the start time of the period 608. The MU-RTS TXS frame is one of the MU-RTS frames that acts as a trigger frame to allocate the TXOP Sharing period.

[0046] Provisional TXOP Limit 525 stores the maximum duration of the provisional TXOP. The maximum duration of the provisional TXOP may be set in microseconds or in 1 TU, i.e., 32 microseconds, from the start time of one of the three patterns described above until the end time of a period 609, which will be described later with reference to FIG. 6. In this way, by transmitting the maximum duration of the provisional TXOP, the receiving AP can identify the maximum duration of the TXOP sharing period. In other words, Provisional TXOP Limit 525 may be in a different format as long as it is information that can identify the maximum duration of the TXOP sharing period.

[0047] The frames in Figures 4 and 5(A) to 5(C) above enable notification of Provisional TXOP from AP 103 to AP 104. Note that the configurations and values ​​of the various fields are merely examples and are not limited to these. For example, the Category value to indicate that the operation is related to C-TDMA may be set to "50," and the C-TDMA Action value may be defined as "3." Also, fields not shown may be inserted.

[0048] For example, information indicating whether TXOP Sharing is performed may be added following the TXOP period in which the MAC frame including the Provisional TXOP notification element 512 is transmitted. For example, if the length of the TXOP Sharing period is set to a predefined length in the wireless system or by another signal, notifying the Provisional TXOP Limit 525 again may result in overhead. Therefore, by notifying only the information indicating whether TXOP Sharing is performed, it is possible to notify the parameters for executing Provisional TXOP while reducing the size of the Action frame.

[0049] 6, a process will be described in which the AP 103, a wireless communication device, executes TXOP sharing to share the acquired TXOP with the AP 104, and the AP 104 communicates with the STA 105 during the TXOP sharing period. That is, the AP 103 is a Sharing AP that shares the TXOP in C-TDMA, and the AP 104 is a Shared AP that shares the transmission opportunity.

[0050] After securing the TXOP, the AP 103 sends a TXOP notification 601 to the AP 104. At this time, the TXOP period notified by the AP 103 is set to the period until TXOP sharing begins. The TXOP notification is performed, for example, by transmitting data or by RTS. In this case, the TXOP period can be set in the Duration / ID 402 in the MAC frame. When the STA 105 connected to the AP 104 receives the TXOP notification 601 from the AP 103, it sets a NAV (Network Allocation Vector) based on the value of Duration / ID 402. The STA 105 that has set the NAV is controlled not to transmit frames. Therefore, the NAV is released during the TXOP Sharing period 608 that follows the TXOP period 606, allowing the STA 105 to send and receive frames during the TXOP Sharing period.

[0051] The AP 103 transmits a Provisional TXOP notification frame 602 to the AP 104 between transmitting the TXOP notification 601 and transmitting the MU-RTS TXS 603. The Provisional TXOP notification frame 602 includes the elements described with reference to FIGS. 5(A) to 5(C) and includes information indicating the maximum duration of the Provisional TXOP. In the following description, the start time of the Provisional TXOP is assumed to be the first pattern described above, that is, the timing when the AP 103 secures the TXOP is the Provisional TXOP. Therefore, the maximum duration of the Provisional TXOP is assumed to be the sum of the TXOP period 606 secured by the AP 103, the TXOP Sharing period 608, and the period 609 during which the AP 103 continues transmitting after the TXOP is returned. However, if the start time of the Provisional TXOP is the second or third pattern, the maximum duration of the Provisional TXOP may be changed accordingly. Furthermore, if the TXOP is not returned, the period 609 does not need to be set.

[0052] During the TXOP period 606, the AP 103 can perform data communication with the STA 106 connected to the AP 103. This data communication may be performed before or after the transmission of the Provisional TXOP notification frame 602. Alternatively, the data communication may be performed simultaneously with the transmission of the TXOP notification 601. That is, during the TXOP period 606, the AP 103, which is the TXOP holder, can perform data communication during periods other than the TXOP Sharing period. On the other hand, during the TXOP Sharing period, the AP 104, which has shared the TXOP from the TXOP holder, can perform data communication.

[0053] Next, when starting TXOP sharing, the AP 103 transmits an MU-RTS TXS 603 to the AP 104. When the AP 104 receives the MU-RTS TXS 603, it responds by transmitting a CTS 604. The AP 103 transmits the MU-RTS TXS 603 so that the STA completes the transmission of the CTS 604 during the TXOP period. In other words, the MU-RTS TXS 603 is a trigger frame that permits TXOP sharing, and the CTS 604 is a response message in which the MU-RTS TXS 603 accepts TXOP sharing.

[0054] During the TXOP sharing period 608, the AP 104 can transmit data to the STA 105. Even if the STA 105 has intercepted the transmission of the AP 103 during the TXOP period 606, the NAV that was set upon receiving the TXOP notification 601 is cancelled, and the STA 105 can respond to the data transmission from the AP 104.

[0055] Furthermore, the AP 104 transmits a TXOP return notification 605 to the AP 103 when the TXOP sharing period 608 ends. The TXOP return notification 605 may be performed, for example, by transmitting a CF (Contention Free)-End frame with the destination set to the AP 103. Alternatively, the TXOP may be implicitly considered to have been returned on the condition that the length of the TXOP sharing period 608 notified in the Provisional TXOP notification frame 602 has elapsed. The AP 103 that has received the TXOP return notification 605 can freely perform data communication during the remaining TXOP period 609. In one example, the TXOP sharing period 608 and the Provisional TXOP period 607 may be considered to have ended on the condition that the length of the Provisional TXOP period 607 has elapsed.

[0056] By the above operation, parameters for Provisional TXOP operation for sharing TXOP between AP 103, AP 104, and STA 105 are notified, and TXOP can be shared efficiently.

[0057] Next, an example of processing executed by the Sharing AP and the Shared AP will be described with reference to the flowcharts of Figures 7 and 8. Figure 7 is a flowchart illustrating an example of communication control executed by AP 103, a wireless communication device operating as a Sharing AP. Figure 8 is a flowchart illustrating an example of communication control executed by AP 104, a wireless communication device operating as a Shared AP. Figures 7 and 8 illustrate an excerpt of a series of procedures from when AP 103 secures a TXOP and shares the TXOP with AP 104 until AP 104 ends the TXOP sharing. Each process shown in the flowchart of Figure 7 is executed by the processor of the control unit 202 of AP 103 executing a computer program stored in the storage unit 201. Each process shown in the flowchart of Figure 8 is executed by the processor of the control unit 202 of AP 104 executing a computer program stored in the storage unit 201. 7 and 8 are realized by the processor of the control unit 202 of each communication device in cooperation with the communication unit 206, the ASIC, DSP, FPGA, etc. of the control unit 202. When clearly indicating the subject of processing, the functional unit described in FIG. 3 will be used as the subject.

[0058] The communication control of the Sharing AP 103 will be described with reference to Fig. 7. In S701, the control unit 301 determines whether or not to perform Provisional TXOP operation for the secured TXOP. If the control unit 301 of the AP 103 performs Provisional TXOP operation (Yes in S701), the process proceeds to S702, and if TXOP Sharing is not to be performed (No in S701), the process proceeds to S707.

[0059] In S702, the control unit 301 of the AP 103 calculates the duration of the provisional TXOP as the TXOP sharing period 608 and the times 606 and 609 used by the AP 103 to perform data communication. Note that if the start time of the provisional TXOP is the second or third pattern described above, the duration of the provisional TXOP period may be determined to be different.

[0060] In S703, the control unit 301 of the AP 103 cooperates with the frame generation unit 302 to transmit, as the TXOP notification 601, a frame in which the length of the TXOP period 606 until the TXOP Sharing period begins is set in the Duration field.

[0061] In S704, the control unit 301 of the AP 103 cooperates with the frame generation unit 302 to transmit a Provisional TXOP notification frame 602 in which the maximum duration of the Provisional TXOP calculated in S702 is set. As described above, the maximum duration of the Provisional TXOP is the sum of the TXOP Sharing period 608 and the periods 606 and 609 used by the AP 103 to perform data communication. The Provisional TXOP notification frame 602 is, for example, the Action frame described with reference to Figures 5(A) to 5(C). Furthermore, the duration of the Provisional TXOP period is set in the Provisional TXOP Limit 525 in Figure 5(C).

[0062] In S705, the control unit 301 of the AP 103 transmits an MU-RTS TXS 603, which is a trigger frame for performing TXOP sharing. In S706, the control unit 301 of the AP 103 waits without transmitting data until a TXOP return notification 605 is transmitted from the AP 104 or the period of the Provisional TXOP set in S704 ends.

[0063] If it is determined in S702 that Provisional TXOP will not be performed (Yes in S702), the control unit 301 of the AP 103 proceeds to S707. In S707, the control unit 301 of the AP 103 works with the frame generation unit 302 to calculate the time required for data transmission, sets the calculated time in the Duration / ID 402 of the transmission frame, and issues a TXOP notification.

[0064] In S708, the control unit 301 of the AP 103 transmits data. After S708, the AP 103 does not transmit the Provisional TXOP notification frame 602 or the MU-RTS TXS 603 in Fig. 6, and ends the processing shown in Fig. 7 without sharing the TXOP.

[0065] Next, communication control of the AP 104 operating as a Shared AP will be described with reference to FIG.

[0066] In S801, the AP 104 identifies that TXOP sharing will be performed by receiving a Provisional TXOP notification from the AP 103. Furthermore, by receiving the Provisional TXOP notification, the AP 104 can specify the maximum duration of the TXOP sharing period.

[0067] Next, in S802, AP 104 receives MU-RTS TXS 601 from AP 103. In S803, control unit 301 of AP 104 responds by transmitting CTS 604 in cooperation with frame generation unit 302. After transmitting the response in S803, operation transitions to a TXOP Sharing period in which a transmission opportunity is secured for AP 104.

[0068] In S804, the control unit 301 of the AP 104 waits for the SIFS time, and then transmits a TXOP notification to the STA 105 connected to itself. Here, the time set as the TXOP period is set to the same value as the length of the TXOP Sharing period 608.

[0069] In S805, the control unit 301 of the AP 104 checks whether there is data to be transmitted. If there is data to be transmitted (Yes in S805), the AP 104 proceeds to S806 and transmits the data to the STA 105. If there is data to be transmitted (No in S805), the AP 104 proceeds to S808.

[0070] After transmitting the data, in S807, the control unit 301 of the AP 104 determines whether the TXOP Sharing period 608 has ended. If the TXOP Sharing period 608 has not ended, the process returns to S805. If the TXOP Sharing period 608 has ended (Yes in S807), the process proceeds to S808.

[0071] In S808, the control unit 301 of the AP 104 transmits a TXOP return notification 605 to the AP 103. The TXOP return notification 605 may be performed, for example, by transmitting a CF-End frame with the destination set to the Sharing AP 103. Furthermore, when the TXOP Sharing period 608 ends and the process proceeds to S808, the control unit 301 of the AP 104 may end the TXOP Sharing period without transmitting a CF-End frame.

[0072] 6 to 8, parameters for executing Provisional TXOP can be notified from AP 103 operating as a Sharing AP to AP 104 operating as a Shared AP. Also, during the TXOP Sharing period, communication between AP 104 operating as a Shared AP and STA 105 connected to the Shared AP becomes possible.

[0073] <Variation 1> In the embodiment, notification of parameters related to Provisional TXOP is performed using a C-TDMA Action frame, but this is not limiting, and notification may also be performed using a QoS Action Action frame. An example of this case will be described using Figures 9(A) to 9(C).

[0074] As shown in Figure 9(A), in the QoS Action frame, the Category subfield 901 of the Action field stores the value "1" indicating that the action frame is a QoS Action. As shown in Figure 9(B), a QoS Action field 911 indicating the specific contents of the QoS Action is placed in Action Details 902 following the Category field. The QoS Action field 911 stores the value "9" indicating that this is a Provisional TXOP notification. This is followed by the Provisional TXOP Information field 912 of Figure 9(B).

[0075] In this way, the parameters related to the Provisional TXOP can be notified using the action frame. Note that the value of the QoS Action field is merely an example and is not limited to this. For example, the value of the QoS Action field may be "10." Also, a method of notifying the Provisional TXOP information using the Provisional TXOP Information field 912 has been shown. In one example, the Provisional TXOP notification element 512 described above with reference to FIG. 5(C) may be placed instead.

[0076] As shown in Fig. 9(C), the Provisional TXOP Information field 912 includes a Provisional TXOP Start time 921 and a Provisional TXOP Limit subfield 922. The contents of each field are the same as those of the fields of the same name in the Provisional TXOP notification element 512 described above with reference to Fig. 5(C), and therefore will not be described here.

[0077] <Variation 2> In the embodiment, the TXOP return notification 605 is performed using a CF-End frame, but this is not limiting, and it may be performed using an Action frame different from the CF-End frame. For example, it can be performed by applying the Action frame for C-TDMA described in FIG.

[0078] An example of the configuration of an Action frame when a TXOP return notification is sent using C-TDMA is shown in Figure 10. In this case, a value indicating the use of the Action frame is stored in the Category field 1001. Here, the value "38" is stored to indicate that the Action frame is used for C-TDMA.

[0079] The Action Details field 1002 includes a field for indicating specific information about the use of the Action frame specified in the Category field. At the beginning of the Action Details field 1002 is a C-TDMA Action field that indicates the specific type of C-TDMA operation. Here, the value "1" is stored to indicate that a TXOP return notification is to be performed among the C-TDMA operations.

[0080] Although the modified example using the C-TDMA category has been shown, the return of the TXOP may be notified by an Action frame of the QoS Action. In this case, as in the first modified example, the Category field stores the value "1" indicating that it is a QoS Action, and the QoS Action field stores the value "10" to indicate that it is a TXOP return notification.

[0081] <Other embodiments> In this embodiment, the parameters related to Provisional TXOP are transmitted in an Action frame. However, other frames may be used as long as they include the Provisional TXOP notification element shown in Fig. 5(C) or the Provisional TXOP Information field shown in Fig. 9(C). For example, the parameters related to Provisional TXOP may be transmitted in a Beacon frame.

[0082] It is also possible to provide a system or device with a recording medium on which program code for software that realizes the above-described functions is recorded, and have the computer (CPU, MPU) of the system or device read and execute the program code stored on the recording medium. In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiments, and the recording medium on which the program code is stored constitutes the above-described device.

[0083] Examples of storage media that can be used to supply the program code include flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, ROMs, and DVDs.

[0084] In addition, the above-mentioned functions may be realized not only by the computer executing the read program code, but also by the operating system (OS) running on the computer performing some or all of the actual processing based on the instructions of the program code. OS is an abbreviation for Operating System.

[0085] Furthermore, the program code read from the storage medium may be written to a memory provided on a function expansion board inserted into a computer or a function expansion unit connected to the computer, and a CPU provided on the function expansion board or function expansion unit may then perform some or all of the actual processing based on the instructions of the program code to realize the above-mentioned functions.

[0086] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0087] The disclosure of this embodiment includes the following communication device, its control method, and program.

[0088] (Item 1) A communication device capable of wireless communication conforming to the IEEE 802.11 series of standards, a radio frame for executing TXOP sharing among a plurality of devices, which transfers a transmission opportunity (TXOP) secured by the communication device to another communication device and secures a TXOP sharing period; a trigger frame that grants a TXOP to another communication device; a transmitting means for transmitting the above to the other communication device during the TXOP period secured by the communication device, A communication device characterized in that the wireless frame includes at least one of predetermined information that can identify the maximum duration of the TXOP Sharing period and information indicating that the TXOP Sharing period will be placed after the TXOP period reserved by the communication device.

[0089] (Item 2) 2. The communication device according to item 1, wherein the predetermined information is included in an information element.

[0090] (Item 3) 3. The communication device according to claim 1, wherein the wireless frame is a Beacon frame.

[0091] (Item 4) 3. The communication device according to claim 1, wherein the wireless frame is an Action frame.

[0092] (Item 5) 5. The communication device according to item 4, wherein the predetermined information is included in a Frame Body field of the Action frame.

[0093] (Item 6) 6. The communication device according to any one of items 1 to 5, wherein the transmitting means transmits the wireless frame after transmitting a second wireless frame for securing a TXOP.

[0094] (Item 7) 7. The communication device according to item 6, wherein the second radio frame includes information that can identify the start timing of the TXOP Sharing period.

[0095] (Item 8) 8. The communication device according to item 7, wherein the second radio frame is an Action frame, and the information capable of identifying the start timing of the TXOP Sharing period is included in a Duration field of the Action frame.

[0096] (Item 9) Further comprising a receiving means for receiving a TXOP return notification from the other communication device, 9. The communication device according to any one of items 1 to 8, wherein the return notification is an Action frame.

[0097] (Item 10) the radio frame includes information indicating that the TXOP Sharing period is placed after the TXOP reserved by the communication device; The communication device described in any one of items 1 to 9, characterized in that the transmitting means transmits a third radio frame including predetermined information that can identify the maximum duration of the TXOP Sharing period before the TXOP reserved by the communication device.

[0098] (Item 11) 11. The communication device according to any one of items 1 to 10, wherein the trigger frame is a Multi-User Request To Send (MU-RTS) trigger frame.

[0099] (Item 12) A communication device capable of wireless communication conforming to the IEEE 802.11 series of standards, a radio frame for executing TXOP sharing among a plurality of devices, in which a transmission opportunity (TXOP) secured by another communication device is transferred from the other communication device during a TXOP sharing period; a trigger frame for transferring a transmission opportunity (TXOP) reserved by the other communication device to the communication device; a receiving means for receiving the TXOP from the other communication device during the TXOP period secured by the other communication device; a transmitting means for transmitting a CTS (Clear To Send) frame in response to receiving the trigger frame; and A communication device characterized in that the wireless frame includes at least one of predetermined information that can identify the maximum duration of the TXOP Sharing period and information indicating that the TXOP Sharing period will be placed after the TXOP period reserved by the communication device.

[0100] (Item 13) A control method executed by a communication device capable of wireless communication conforming to the IEEE 802.11 series of standards, comprising: a radio frame for executing TXOP sharing among a plurality of devices, which transfers a transmission opportunity (TXOP) secured by the communication device to another communication device and secures a TXOP sharing period; a trigger frame that grants a TXOP to another communication device; to the other communication device during the TXOP period secured by the communication device; A control method characterized in that the radio frame includes at least one of predetermined information that can identify the maximum duration of the TXOP Sharing period and information indicating that the TXOP Sharing period will be placed after the TXOP period reserved by the communication device.

[0101] (Item 14) A control method executed by a communication device capable of wireless communication conforming to the IEEE 802.11 series of standards, comprising: a radio frame for executing TXOP sharing among a plurality of devices, in which a transmission opportunity (TXOP) secured by another communication device is transferred from the other communication device during a TXOP sharing period; a trigger frame for transferring a transmission opportunity (TXOP) reserved by the other communication device to the communication device; from the other communication device during a TXOP period secured by the other communication device; transmitting a CTS (Clear To Send) frame in response to receiving the trigger frame; Including, A control method characterized in that the radio frame includes at least one of predetermined information that can identify the maximum duration of the TXOP Sharing period and information indicating that the TXOP Sharing period will be placed after the TXOP period reserved by the communication device.

[0102] (Item 15) 13. A program for causing a computer to function as the communication device according to any one of items 1 to 12.

[0103] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0104] 103, 104: AP, 105, 106: STA, 201: storage unit, 202: control unit, 203: function unit, 204: input unit, 205: output unit, 206: communication unit

Claims

1. A communication device capable of wireless communication conforming to the IEEE 802.11 series of standards, a radio frame for executing TXOP sharing among a plurality of devices, which transfers a transmission opportunity (TXOP) secured by the communication device to another communication device to secure a TXOP sharing period; a trigger frame that grants a TXOP to another communication device; a transmitting means for transmitting the above to the other communication device during a TXOP period secured by the communication device, the radio frame includes at least one of predetermined information that can identify the maximum duration of the TXOP sharing period and information that indicates that the TXOP sharing period will be placed after the TXOP period reserved by the communication device.

2. The communication device according to claim 1 , wherein the predetermined information is included in an Information Element.

3. The communication device according to claim 1 , wherein the radio frame is a beacon frame.

4. The communication device according to claim 1 , wherein the radio frame is an Action frame.

5. 5. The communication device according to claim 4, wherein the predetermined information is included in a Frame Body field of the Action frame.

6. 2. The communication device according to claim 1, wherein the transmitting means transmits the radio frame after transmitting a second radio frame for securing a TXOP.

7. The communication device according to claim 6 , wherein the second radio frame includes information capable of identifying a start timing of the TXOP sharing period.

8. The communication device according to claim 7 , wherein the second radio frame is an Action frame, and the information capable of identifying the start timing of the TXOP Sharing period is included in a Duration field of the Action frame.

9. further comprising a receiving means for receiving a TXOP return notification from the other communication device; 2. The communication device according to claim 1, wherein the return notification is an Action frame.

10. the radio frame includes information indicating that the TXOP Sharing period is arranged after the TXOP reserved by the communication device; 2. The communication device according to claim 1, wherein the transmitting means transmits a third radio frame including predetermined information capable of specifying a maximum duration of the TXOP sharing period before the TXOP reserved by the communication device.

11. 2. The communication device according to claim 1, wherein the trigger frame is a multi-user request to send (MU-RTS) trigger frame.

12. A communication device capable of wireless communication conforming to the IEEE 802.11 series of standards, a radio frame for executing TXOP sharing among a plurality of devices, in which a transmission opportunity (TXOP) secured by another communication device is transferred from the other communication device as a TXOP sharing period; a trigger frame for transferring a transmission opportunity (TXOP) secured by the other communication device to the communication device; a receiving means for receiving the above-mentioned signal from the other communication device during a TXOP period secured by the other communication device; a transmitting means for transmitting a CTS (Clear To Send) frame in response to receiving the trigger frame; and the radio frame includes at least one of predetermined information that can identify the maximum duration of the TXOP sharing period and information that indicates that the TXOP sharing period will be placed after the TXOP period reserved by the communication device.

13. A control method executed by a communication device capable of wireless communication conforming to the IEEE 802.11 series of standards, comprising: a radio frame for executing TXOP sharing among a plurality of devices, which transfers a transmission opportunity (TXOP) secured by the communication device to another communication device to secure a TXOP sharing period; a trigger frame that grants a TXOP to another communication device; to the other communication device during the TXOP period secured by the communication device; a control method, characterized in that the radio frame includes at least one of predetermined information that can identify the maximum duration of the TXOP sharing period and information indicating that the TXOP sharing period will be placed after the TXOP period secured by the communication device.

14. A control method executed by a communication device capable of wireless communication conforming to the IEEE 802.11 series of standards, comprising: a radio frame for executing TXOP sharing among a plurality of devices, in which a transmission opportunity (TXOP) secured by another communication device is transferred from the other communication device as a TXOP sharing period; a trigger frame for transferring a transmission opportunity (TXOP) secured by the other communication device to the communication device; from the other communication device during a TXOP period secured by the other communication device; transmitting a CTS (Clear To Send) frame in response to receiving the trigger frame; Including, a control method, characterized in that the radio frame includes at least one of predetermined information that can identify the maximum duration of the TXOP sharing period and information indicating that the TXOP sharing period will be placed after the TXOP period secured by the communication device.

15. A program for causing a computer to function as the communication device according to any one of claims 1 to 12.

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