Communication device, program, and communication method

Abstract

This communication device (STA) for wireless communication with an opposing device (AP) conforming to the IEEE 802.11 series standard according to the present invention comprises: a reception means for receiving, from the opposing device, an MU-RTS trigger frame indicating performing of TXOP sharing for sharing a portion of a TXOP, and a CTS frame that is a response to the MU-RTS trigger frame; a period acquisition means for acquiring a TXOP sharing period that is set on the basis of duration information about the MU-RTS TXS trigger frame or the CTS frame; and a state transition means. The state transition means controls to enter a Listen state during the TXOP sharing period in the MU-RTS trigger frame when the TXOP is not allocated to itself in the TXOP sharing period.

Description

Communication device, program, and communication method

[0001] The present invention relates to a communication device, a program, and a communication method.

[0002] 2. Description of the Related Art With the recent increase in the amount of data being communicated, development of communication technologies such as wireless LANs (Local Area Networks) has been progressing.

[0003] The IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard series is known as a major communication standard for wireless LANs.

[0004] The IEEE 802.11 standard series includes standards such as IEEE 802.11a / b / g / n / ac / ax.

[0005] For example, the latest standard, IEEE 802.11ax, uses OFDMA to standardize technology that not only achieves a high peak throughput of up to 9.6 gigabits per second (Gbps), but also improves communication speeds under congested conditions (see Patent Document 1).

[0006] Incidentally, OFDMA (Orthogonal Frequency Division Multiple Access) is an abbreviation for Orthogonal frequency-division multiple access.

[0007] A task group called IEEE802.11be was established to develop a successor standard aimed at further improving throughput, improving frequency utilization efficiency, and improving communication latency.

[0008] The task group is creating a specification document, and a draft of the document has been published.

[0009] The IEEE 802.11be standard introduces multi-link communication, in which, for example, a counterpart device functioning as an AP establishes multiple links with a communication device functioning as a STA via multiple different frequency channels, and communicates in parallel.

[0010] It should be noted that AP is an abbreviation for Access Point, and hereinafter, an opposing device that functions as an AP may be simply referred to as an AP.

[0011] Furthermore, STA is an abbreviation for Station, and hereinafter, a communication device that functions as a STA may be simply referred to as a STA.

[0012] Additionally, the IEEE 802.11be standard expands the maximum frequency bandwidth of radio waves to 320 MHz as one of the measures to improve throughput.

[0013] In addition, in IEEE802.11ax, an AP transmits a trigger frame to a communicating STA in order to control the uplink communication of the STA.

[0014] The trigger frame is also used in IEEE802.11be and is transmitted in combination with the above-mentioned Multi-link and a frequency bandwidth of 320 MHz.

[0015] IEEE 802.11be introduces a method of allocating and sharing a portion of a transmission opportunity (TXOP) secured by an AP for a certain period of time.

[0016] Specifically, a method called Triggered TXOP sharing is introduced in which an AP sends a Trigger frame to a STA, and the STA allocates and shares a part of the TXOP secured by the AP for a certain period from the Trigger frame.

[0017] The AP then shares the acquired TXOP with the STAs designated by the AP, and prohibits transmission by STAs other than the designated ones during this TXOP sharing period, thereby avoiding unnecessary collisions of transmission frames and enabling efficient communication.

[0018] In addition, a task group called IEEE802.11bn has been established to formulate a successor standard to IEEE802.11be, which aims to improve reliability and further reduce communication latency.

[0019] The use of Triggered TXOP sharing in IEEE 802.11bn is also being considered.

[0020] Japanese Patent Application Laid-Open No. 2018-50133

[0021] In triggered TXOP sharing, while a STA that has been assigned a TXOP is communicating with another STA or between a STA that has been assigned a TXOP and an AP, a STA that has not been assigned a TXOP faces the following problem.

[0022] In other words, if a STA that has not been assigned a TXOP is in an awake state during a TXOP sharing period, the STA that has not been assigned a TXOP is unlikely to receive a packet addressed to it, resulting in unnecessary power consumption.

[0023] The present invention has been made in view of the above circumstances, and one of its objects is to suppress unnecessary power consumption of a communication device that functions as a STA to which a TXOP has not been allocated.

[0024] In order to achieve the above object, the present invention is realized by the following configuration.

[0025] A communication device of the present invention functions as an STA that performs wireless communication with an opposite device that functions as an AP conforming to the IEEE802.11 series standard, and includes: receiving means capable of receiving, from the opposite device, an MU-RTS TXS Trigger frame indicating that TXOP sharing will be performed to share a part of a TXOP, and a CTS frame that is a response to the MU-RTS TXS Trigger frame; period acquisition means for acquiring a TXOP sharing period that is set based on Duration information of the MU-RTS TXS Trigger frame or the CTS frame; and state transition means for controlling transition of an active state, wherein the state transition means controls the TXOP sharing period that is set based on Duration information of the MU-RTS TXS Trigger frame in the MU-RTS TXS Trigger frame. If a TXOP is not allocated to itself during the TXOP sharing period, it controls to enter the Listen state during the TXOP sharing period.

[0026] According to the present invention, it is possible to suppress unnecessary power consumption of a communication device functioning as a STA to which a TXOP has not been allocated.

[0027] FIG. 1 is a diagram showing an example of the configuration of a wireless network according to a first embodiment of the present invention. FIG. 2 is a diagram showing an example of the hardware configuration of a communication device that is an STA according to a first embodiment of the present invention. FIG. 3 is a block diagram showing the functional configuration of a communication device that is an STA according to a first embodiment of the present invention. FIG. 4 is a sequence diagram showing an example of communication by Triggered TXOP sharing according to a first embodiment of the present invention. FIG. 5 is a flowchart showing an example of MU-RTS processing of a communication device that functions as an STA according to a first embodiment of the present invention. FIG. 6 is a diagram showing values ​​of the Triggered TXOP Sharing Mode subfield and the contents indicated by each value according to a first embodiment of the present invention. FIG. 7 is a flowchart showing an example of MU-RTS processing of an opposing device that is an AP according to a first embodiment of the present invention. FIG. 8 is a diagram showing an example of a field indicating whether a communication device that is an STA that has not been assigned a TXOP during a TXOP sharing period included in an MU-RTS Trigger frame according to a first embodiment of the present invention enters a Power save state. 10 is a flowchart illustrating an example of MU-RTS processing of a communication device functioning as a STA according to a second embodiment of the present invention.

[0028] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a mode for carrying out the present invention (hereinafter referred to as an "embodiment") will be described in detail with reference to the accompanying drawings.

[0029] However, the following embodiments do not limit the scope of the present invention as defined by the claims.

[0030] Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solutions of the present invention.

[0031] It should be noted that the same elements are denoted by the same numbers or symbols throughout the description of the embodiments.

[0032] First Embodiment FIG. 1 is a diagram showing an example of the configuration of a wireless network 105 according to a first embodiment of the present invention.

[0033] The opposite device 101 is a device that functions as an access point (AP) that has the role of constructing a wireless network 105 and is capable of communicating with the communication devices 102 , 103 , and 104 .

[0034] Furthermore, the communication devices 102 , 103 , and 104 are communication devices that function as stations (STAs) and can participate in the wireless network 105 .

[0035] The opposite device 101 and the communication devices 102 to 104 are each capable of performing wireless communication in accordance with the IEEE 802.11bn standard.

[0036] IEEE is an abbreviation for Institute of Electrical and Electronics Engineers.

[0037] Furthermore, in order to explain the same content between the opposing device 101 and the communication devices 102 to 104, when there is no need to distinguish between the opposing device 101 and the communication devices 102 to 104, they may be simply referred to as devices 101 to 104.

[0038] The devices 101 to 104 are capable of communicating in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands.

[0039] Additionally, devices 101-104 can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz.

[0040] The devices 101 to 104 can realize multi-user (MU) communication in which signals from multiple users are multiplexed by performing OFDMA communication conforming to the IEEE802.11bn standard.

[0041] It should be noted that OFDMA is an abbreviation for Orthogonal Frequency Division Multiple Access, and MU is an abbreviation for Multi User.

[0042] In OFDMA communication, parts (RUs) of the divided frequency band are assigned to the communication devices 102 to 104, which are STAs, so as not to overlap with each other, and the carrier waves of the communication devices 102 to 104 are orthogonal to each other.

[0043] It should be noted that RU is an abbreviation for Resource Unit.

[0044] Therefore, the opposite device 101, which is an AP, can communicate in parallel with a plurality of communication devices 102 to 104, which are STAs.

[0045] Although the devices 101 to 104 are described as being compatible with the IEEE802.11bn standard, they may also be compatible with a standard earlier than the IEEE802.11bn standard.

[0046] Specifically, the devices 101 to 104 may be compatible with at least one of the IEEE 802.11a / b / g / n / ac / ax / be standards.

[0047] In addition to the IEEE802.11 series standards, other communication standards such as Bluetooth (registered trademark), NFC, UWB, ZigBee, and MBOA may also be supported.

[0048] It should be noted that UWB is an abbreviation for Ultra Wide Band, MBOA is an abbreviation for Multi Band OFDM Alliance, and NFC is an abbreviation for Near Field Communication.

[0049] UWB also includes wireless USB, wireless 1394, WiNET, and the like.

[0050] Furthermore, the devices 101 to 104 may be compatible with a communication standard for wired communication such as a wired LAN.

[0051] Specific examples of the AP-type opposing device 101 include, but are not limited to, a wireless LAN router and a personal computer (PC).

[0052] The opposite device 101 may also be an information processing device such as a wireless chip that can perform wireless communication in accordance with the IEEE 802.11bn standard.

[0053] Specific examples of the communication devices 102 to 104 that are STAs include, but are not limited to, cameras, tablets, smartphones, PCs, mobile phones, and video cameras.

[0054] Furthermore, the communication devices 102 to 104 may be information processing devices such as wireless chips that can perform wireless communication in accordance with the IEEE 802.11bn standard.

[0055] Furthermore, although the wireless network 105 in FIG. 1 is composed of one AP-based opposite device 101 and three STA-based communication devices 102 to 104, the number of AP-based opposite devices and STA-based communication devices is not limited to this.

[0056] The opposite device 101, which is an AP, can allocate and share part of the secured TXOP to the communication devices 102 to 104, which are STAs, by using Triggered TXOP sharing.

[0057] Triggered TXOP sharing starts when the opposite device 101, which is an AP, transmits an MU-RTS TXS Trigger frame to the communication devices 102 to 104, which are STAs.

[0058] It should be noted that MU-RTS is an abbreviation for Multi User-Request To Send.

[0059] In addition, hereinafter, the MU-RTS TXS Trigger frame will be referred to as the MU-RTS Trigger frame.

[0060] A communication device that is an STA to which a portion of the TXOP has been allocated can transmit data to the opposite device 101 that is an AP or to another communication device that is an STA during the TXOP sharing period.

[0061] For example, assume that the communication device 102 is a STA that has been allocated a portion of the TXOP, and the communication devices 103 and 104 are STAs that have not been allocated a portion of the TXOP.

[0062] In this case, the communication device 102 that has been allocated a portion of the TXOP can transmit data to the opposite device 101, which is an AP, or to another communication device 103 or 104, which is an STA, during the TXOP sharing period.

[0063] The partner with which communication will be performed during the TXOP sharing period can be specified in the Triggered TXOP sharing mode subfield included in the Common Info field of the MU-RTS Trigger frame.

[0064] In other words, in the above example, it is possible to specify whether communication will be performed between the communication device 102 and the opposite device 101 during the TXOP sharing period, or between the communication device 102 and another communication device (e.g., the communication device 103 or 104).

[0065] [Hardware Configuration of the Counterpart Device 101 and the Communication Devices 102 to 104] FIG. 2 is a diagram showing an example of the hardware configuration of the communication devices 102 to 104, which are STAs according to the first embodiment of the present invention.

[0066] The communication devices 102 to 104 may all have the same hardware configuration.

[0067] Therefore, in the following description of the hardware configuration, when it is not necessary to describe it with a number, it will simply be referred to as a communication device without a number.

[0068] The hardware configuration of the opposing device 101, which is an AP, may also be the same as the hardware configuration example shown in FIG.

[0069] Therefore, the following description of the hardware configuration with reference to FIG. 2 also includes a description of the hardware configuration of the opposing device 101, which is an AP.

[0070] The communication device includes 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 .

[0071] (Storage Unit 201) The storage unit 201 is configured with memories such as ROM and RAM, and stores computer programs for performing various operations described below, and various types of information such as communication parameters for wireless communication.

[0072] It should be noted that ROM stands for Read Only Memory, and RAM stands for Random Access Memory.

[0073] In addition to memories such as ROM and RAM, the storage unit 201 may also be a storage medium such as a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, or a DVD.

[0074] Furthermore, the storage unit 201 may include a plurality of memories.

[0075] (Control Unit 202) The control unit 202 is configured with one or more processors such as a CPU or an MPU, and executes computer programs stored in the storage unit 201 to control the entire communication device.

[0076] It should be noted that CPU stands for Central Processing Unit, and MPU stands for Micro Processing Unit.

[0077] The control unit 202 may control the entire communication device in cooperation with a computer program stored in the storage unit 201 and an OS (Operating System).

[0078] The control unit 202 also generates data and signals to be transmitted in communication with other devices (for example, the opposing device 101, which is an AP, and other communication devices, which are STAs).

[0079] In the case of the control unit 202 of the opposite device 101, the other devices are, for example, the communication devices 102 to 104 which are STAs.

[0080] Furthermore, the control unit 202 may be provided with multiple processors such as multi-core processors, and the entire communication device may be controlled by the multiple processors.

[0081] In addition, the control unit 202 controls the function unit 203 to perform predetermined processes such as wireless communication, imaging, printing, and projection.

[0082] (Function Unit 203) The function unit 203 is hardware for executing predetermined processes to realize the intended functions of the communication device according to the type of the communication device.

[0083] For example, if the communication device is a camera or the like, the functional unit 203 includes a necessary optical lens unit, an optical system that controls the aperture, zoom, focus, etc., and an image sensor that converts the light (image) introduced through the optical lens unit into an electrical video signal.

[0084] (Input Unit 204) The input unit 204 is hardware necessary for accepting various operations from the user.

[0085] For example, there is a power button for turning the power on and off, a touch panel for inputting settings, and the like.

[0086] (Output Unit 205) The output unit 205 outputs various information to the user via a monitor screen and a speaker.

[0087] 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.

[0088] It should be noted that both the input unit 204 and the output unit 205 may be realized by a single module, such as a touch panel.

[0089] Furthermore, the input unit 204 and the output unit 205 may be integrated with the communication device or may be separate from the communication device.

[0090] (Communication Unit 206) The communication unit 206 controls wireless communication conforming to the IEEE802.11bn standard.

[0091] The communication unit 206 may control wireless communication conforming to other IEEE802.11 series standards in addition to the IEEE802.11bn standard, and may control wired communication such as a wired LAN.

[0092] The communication unit 206 controls the antenna 207 to transmit and receive radio signals generated by the control unit 202 for wireless communication.

[0093] If the communication device is compatible with the NFC standard, Bluetooth standard, or the like in addition to the IEEE 802.11bn standard, the communication unit 206 may control wireless communication in accordance with these communication standards.

[0094] Furthermore, if the communication device is capable of performing wireless communication in accordance with a plurality of communication standards, it may be configured to have separate communication units 206 and antennas 207 corresponding to the respective communication standards.

[0095] The communication device communicates data such as image data, document data, and video data with other devices (for example, the opposing device 101 which is an AP, and other communication devices which are STAs) via the communication unit 206.

[0096] In the case of the communication unit 206 of the opposite device 101, the other devices are, for example, the communication devices 102 to 104 which are STAs.

[0097] (Antenna 207) The antenna 207 is an antenna capable of communication in the 2.4 GHz band, the 5 GHz band, the 6 GHz band, and the like.

[0098] The antenna 207 may be configured as a separate unit from the communication unit 206, or may be configured together with the communication unit 206 as a single module.

[0099] Furthermore, there is no particular limit to the number of antennas that a communication device has, and the number of antennas that a communication device has may be two or more, and the communication device may be equipped with one or more antennas that are different for each frequency band.

[0100] Furthermore, if the communication device has multiple antennas, the communication device may have a communication unit 206 for each antenna.

[0101] [Functional Configuration of Communication Devices 102 to 104] FIG. 3 is a block diagram showing the functional configuration of communication devices 102 to 104, which are STAs according to the first embodiment of the present invention.

[0102] Furthermore, FIG. 3 is merely an example, and the multiple functional blocks shown in FIG. 3 may be integrated into one functional block, or one functional block may be divided into multiple functional blocks.

[0103] The communication devices 102 to 104 may all have the same functional configuration.

[0104] Therefore, in the following description of the functional configuration, when it is not necessary to describe the components by adding a number, the components will simply be referred to as communication devices without adding a number.

[0105] (TXOP sharing processing unit 301) The TXOP sharing processing unit 301 is a block that performs overall control when triggered TXOP sharing is instructed by the opposite device 101, which is an AP.

[0106] For example, when a TXOP is allocated to the TXOP sharing processing unit 301, the TXOP sharing processing unit 301 causes a frame transmitting / receiving unit 305 (described later) to transmit data during the TXOP sharing period.

[0107] For example, during the TXOP sharing period, the TXOP sharing processing unit 301 causes the frame transmitting / receiving unit 305 to transmit data to a destination device, for example, the opposing device 101 which is an AP or another communication device which is an STA.

[0108] That is, if the device itself is the communication device 102, the TXOP sharing processing unit 301 causes the frame transmitting / receiving unit 305 to transmit data to the opposite device 101 as the destination or to another communication device 103 or 104 as the STA.

[0109] Furthermore, when the TXOP sharing processing unit 301 is not assigned a TXOP, it causes the power save control unit 303 (described later) to perform control to switch to a power save state or a listen state.

[0110] (NAV Setting Unit 302) The NAV setting unit 302 is a block that sets a NAV indicating its own transmission prohibition time based on duration information included in the MU-RTS Trigger frame received from the opposing device 101, which is an AP.

[0111] The NAV setting unit 302 is a block that sets the NAV indicating its own transmission prohibition time based on the duration information included in the CTS frame received from a communication device that is another STA.

[0112] That is, the NAV setting unit 302 is a block that sets the NAV indicating its own transmission prohibition time based on the duration information included in the received MU-RTS Trigger frame or the received CTS frame.

[0113] Note that MU-RTS is an abbreviation for Multi User-Request To Send, CTS is an abbreviation for Clear To Send, and NAV is an abbreviation for Network Allocation Vector.

[0114] (Power save control unit 303) The power save control unit 303 is a block that controls whether the state to enter is a power save state, a listen state, or an awake state, and is an example of a state transition means according to the present invention.

[0115] That is, the power save control unit 303 (state transition means) controls the transition of the startup state of the communication device (controls which state to enter).

[0116] The power save state is a state in which frames are not transmitted or received or can be received intermittently in order to save power.

[0117] The Power save state may also be called the Doze state.

[0118] The Listen state is a state in which only frames can be received.

[0119] Furthermore, the Awake state is a state in which frames can be transmitted and received after the Power save state and the Listen state are released.

[0120] (MU-RTS Trigger Frame Processing Unit 304) The MU-RTS Trigger frame processing unit 304 is a block for analyzing and processing the MU-RTS Trigger frame received from the opposing device 101, which is an AP.

[0121] The MU-RTS Trigger frame processing unit 304 is also a block for analyzing and processing a CTS frame received from another communication device.

[0122] As will be described later, the MU-RTS Trigger frame processing unit 304 obtains the TXOP sharing period that is set based on the Duration information of the MU-RTS TXS Trigger frame or the CTS frame, for example.

[0123] The MU-RTS Trigger frame processing unit 304 is an example of a period acquisition unit that acquires the TXOP sharing period according to the present invention.

[0124] Then, the communication device performs TXOP sharing processing, NAV setting, and power save control according to the contents of the MU-RTS Trigger frame.

[0125] (Frame Transmitting / Receiving Unit 305) The frame transmitting / receiving unit 305 is a block for transmitting and receiving control frames, management frames, and data frames including the MU-RTS Trigger frame, and is an example of the transmitting means and receiving means according to the present invention.

[0126] Next, an example of communication using triggered TXOP sharing will be described.

[0127] FIG. 4 is a sequence diagram showing an example of communication by triggered TXOP sharing according to the first embodiment of the present invention.

[0128] In this example, communication is performed during a TXOP sharing period between a communication device 102 (hereinafter also referred to as STA1) which is an STA and a counterpart device 101 (hereinafter also referred to as AP) which is an AP.

[0129] The communication device 103 or 104, which is a STA, is shown as STA2 in FIG. 4, and will hereinafter also be referred to simply as STA2.

[0130] There may also be STA3, in which case, for example, STA3 may perform the same operations as STA2.

[0131] In step 401, the AP transmits an MU-RTS Trigger frame to all STAs (STA1, STA2) within the network.

[0132] In this example, a portion of the TXOP 411 (see TXOP sharing period 412) is allocated to STA1.

[0133] STA1, which has been assigned a TXOP, responds with a CTS frame 403 and then transmits a data frame 404 to the AP.

[0134] The AP transmits a BA (Block ACK) 405, which is an acknowledgment to the data frame, to STA1, and thereafter continues exchanging data frames and BAs during a TXOP sharing period 412 as necessary.

[0135] On the other hand, STA2 has not been assigned a TXOP, and therefore sets NAV402 during the TXOP sharing period.

[0136] During this time, STA2 enters, for example, a power save state.

[0137] As will be described later, STA2 may be in a listen state during this time.

[0138] During the remaining TXOP period 413 after the TXOP sharing period 412 has ended, STA2 is in the Listen state because there is a possibility that it may receive a frame from the AP.

[0139] In this way, STA2 enters the power save state during the TXOP sharing period 412, thereby reducing power consumption.

[0140] As will be described later, STA2 may enter the Listen state during the TXOP sharing period 412, but power consumption can be reduced compared to when the STA2 remains in the Awake state.

[0141] Next, an example of MU-RTS processing of a communication device that is a STA will be described.

[0142] FIG. 5 is a flowchart showing an example of MU-RTS processing of a communication device functioning as a STA according to the first embodiment of the present invention.

[0143] The flowchart in Figure 5 can be understood as a flowchart when one of the communication devices 102 to 104, which are STAs, is the main focus, and as in the past, when there is no need to distinguish between them, they may simply be referred to as communication devices.

[0144] This process is started in response to the frame transmission / reception unit 305 of the communication device that is the STA receiving the MU-RTS Trigger frame from the opposite device 101 that is the AP.

[0145] (S501) The communication device determines whether the received MU-RTS Trigger frame specifies TXOP sharing, and if so, proceeds to S502, and if not, proceeds to S512.

[0146] Specifically, the MU-RTS Trigger frame processing unit 304 analyzes the MU-RTS Trigger frame received from the opposite device 101, which is an AP, and determines whether TXOP sharing is specified.

[0147] TXOP sharing can be specified in the Triggered TXOP Sharing Mode subfield included in the Common Info field of the MU-RTS Trigger frame.

[0148] Here, the Triggered TXOP Sharing Mode subfield will be described.

[0149] FIG. 6 is a diagram showing values ​​of the Triggered TXOP Sharing Mode subfield and the contents indicated by each value according to the first embodiment of the present invention.

[0150] As shown in FIG. 6, if the value of the subfield is "0", it indicates that the MU-RTS Trigger frame does not specify TXOP sharing.

[0151] That is, in S501, if the value of the subfield is not "0", the process proceeds to S502, and if the value of the subfield is "0", the process proceeds to S512.

[0152] If the value of the subfield is "1" or "2", it indicates that TXOP sharing is specified.

[0153] Specifically, when the value of the subfield is "1", this indicates that the communication device, which is a STA to which a TXOP is assigned, can transmit an MPDU to the opposite device 101, which is an AP.

[0154] It should be noted that MPDU is an abbreviation for MAC Protocol Data Unit.

[0155] Furthermore, if the value of the subfield is "2", this indicates that the communication device that is a STA to which the TXOP is assigned can transmit an MPDU to the opposite device 101 that is an AP or to another communication device that is a STA.

[0156] Specifically, if the communication device that is the STA to which the TXOP is assigned is the communication device 102 , the communication device 102 indicates that it can transmit an MPDU to the opposite device 101 or the communication devices 103 and 104 .

[0157] (S502) The communication device determines whether or not a TXOP has been allocated to itself, and if so, proceeds to S509, and if not, proceeds to S503.

[0158] Specifically, the MU-RTS Trigger frame processing unit 304 analyzes the MU-RTS Trigger frame received from the opposite device 101, which is an AP, and determines whether or not a TXOP has been allocated to itself.

[0159] (S503) The communication device receives a CTS frame from a communication device functioning as a STA to which a TXOP is allocated.

[0160] Specifically, the frame transmitting / receiving unit 305 receives a CTS frame from a communication device functioning as a STA to which a TXOP has been allocated.

[0161] (S504) The communication device sets the NAV based on the Duration information included in the MU-RTS Trigger frame or the CTS frame, and proceeds to S504a.

[0162] Specifically, the NAV setting unit 302 sets the NAV indicating its own transmission prohibition time based on the Duration information included in the MU-RTS Trigger frame or the CTS frame.

[0163] (S504a) Subsequently, the communication device determines whether the value of the Triggered TXOP Sharing Mode subfield included in the MU-RTS Trigger frame is "1" or "2."

[0164] Specifically, the MU-RTS Trigger frame processing unit 304 analyzes the MU-RTS Trigger frame.

[0165] Then, the MU-RTS Trigger frame processing unit 304 determines whether the value of the Triggered TXOP Sharing Mode subfield is "1" or "2."

[0166] Note that if S501 returns Yes, that is, if the value of the subfield is not "0", the process proceeds to S504a, and the determination here is whether the value of the subfield is "1" or "2".

[0167] If the value of the subfield is "1", the process proceeds to S505, and if the value of the subfield is "2", the process proceeds to S507.

[0168] (S505) As explained above, if the value of the subfield is "1", this indicates that the communication device, which is a STA, to which the TXOP is allocated can transmit an MPDU to the opposite device 101, which is an AP.

[0169] Furthermore, in order to proceed to S504a, S502 must be No, that is, no TXOP must be allocated.

[0170] Therefore, the power save control unit 303 of the communication device performs control to enter the power save state because there is no possibility of receiving data.

[0171] That is, the power save control unit 303 of the communication device sets the state to the power save state.

[0172] In this way, when a TXOP is not allocated to itself, control is performed to enter the power save state during the TXOP sharing period depending on information indicating whether it is okay to enter the power save state, i.e., whether there is a possibility of receiving data.

[0173] (S506) The reason there is no possibility of receiving the above data is because the TXOP sharing period is in progress, so the device remains in the power save state and waits until the TXOP sharing period ends.

[0174] (S507) Then, when the TXOP sharing period ends, there is a possibility that data will be received from the opposite device 101 which is an AP, or from a communication device which is a STA to which a TXOP has been allocated.

[0175] Therefore, the power save control unit 303 of the communication device performs control to enter the listen state.

[0176] That is, the power save control unit 303 of the communication device sets the state to the listen state.

[0177] On the other hand, if the value of subfield is "2", that is, if the communication device is a STA that has been assigned a TXOP, it can transmit an MPDU to the opposing device 101 that is an AP or to another communication device that is a STA (S504a is No), processing of S507 is also performed.

[0178] In this case, the process proceeds to S507 without performing the process of S506, and the power save control unit 303 of the communication device performs control to enter the Listen state during the TXOP sharing period.

[0179] (S508) Subsequently, if the communication device receives data from the opposite device 101, which is the AP, during the remaining TXOP period, the communication device performs data communication with the opposite device 101.

[0180] Here, the communication device is in an Awake state while transmitting a response frame such as a BA frame to the opposing device 101 which is the AP, and once this is completed, it returns to the Listen state again.

[0181] The control to enter the Awake state and the control to return to the Listen state are performed by the power save control unit 303 of the communication device.

[0182] Furthermore, the communication device may transition from the Listen state to the Awake state when it receives a predetermined frame from the opposite device 101 that is an AP, or from a communication device that is a STA that has been assigned a TXOP.

[0183] The transition from the Listen state to the Awake state is also controlled by the power save control unit 303 of the communication device.

[0184] The specified frame is a frame for notifying that the opposing device 101, which is an AP, or a communication device, which is a STA that has been assigned a TXOP, will transmit a frame containing data, or a frame for notifying the start of a frame exchange sequence, etc.

[0185] For example, it may be an initial control frame.

[0186] The predetermined frame may also be a frame for notifying that a communication device, which is a STA to which a TXOP has been allocated, will give up at least a portion of the allocated TXOP, such as a Null QoS frame.

[0187] Then, the communication device that receives the predetermined frame may receive a series of data, transmit a response frame such as a BA frame in response to the received data, and then return to the Listen state again.

[0188] After the data communication with the opposite device 101, which is the AP, is completed, the communication device ends the MU-RTS process.

[0189] Then, when the communication device finishes the MU-RTS process, it returns to the power control state it was in before starting the MU-RTS process.

[0190] For example, if the device was operating in Power save mode or EMLSR mode, it will return to those modes.

[0191] Also, for example, if the device has always been in the Awake state, it returns to that mode.

[0192] (S509) If S502 is Yes, that is, if the TXOP is allocated to itself, the frame transmitting / receiving unit 305 of the communication device transmits a CTS frame as a response to the opposite device 101, which is the AP, and proceeds to S510.

[0193] (S510) The communication device determines whether the TXOP sharing period has ended, and if it has ended, proceeds to S507, and if it has not ended, proceeds to S511.

[0194] (S511) The communication device performs data communication with the opposite device 101, which is an AP, or with another communication device, which is a STA, using the acquired TXOP (the TXOP assigned to itself).

[0195] For example, if the communication device 102 is a STA to which a TXOP is assigned, the communication device 102 performs data communication with the opposite device 101, which is an AP, or with communication devices 103 and 104, which are other STAs.

[0196] When the data communication is completed, the process returns to S510, and the TXOP sharing period will eventually end, so the process proceeds to S507.

[0197] (S512) On the other hand, if S501 is No, that is, if the MU-RTS Trigger frame received by the communication device does not specify TXOP sharing, the communication device performs the determination of S512.

[0198] Specifically, the communication device determines whether or not it is the destination of DL MU (Down Link Multi User) communication, and if it is the destination, proceeds to S513, and if it is not the destination, proceeds to S515.

[0199] (S513) The communication device transmits a CTS frame as a response to the opposing device 101, which is the AP.

[0200] (S514) The communication device communicates DL MU data with the opposite device 101, which is the AP, and when the DL MU data communication process is completed, ends the MU-RTS process.

[0201] (S515) On the other hand, if S512 is No, the communication device receives a CTS frame from the communication device that is the other STA that is the destination of the DL MU communication, and proceeds to S516.

[0202] That is, if the communication device itself is not the destination of DL MU (Down Link Multi User) communication, the communication device receives a CTS frame from another communication device that is the destination of DL MU communication, and proceeds to S516.

[0203] For example, if the communication device 102 is the communication device 102 and the communication device that is the other STA that is the destination of the DL MU communication is the communication device 103, the communication device 102 receives a CTS frame from the communication device 103 that is the destination of the DL MU communication, and proceeds to S516.

[0204] (S516) The communication device sets the NAV based on the Duration information included in the MU-RTS Trigger frame or the CTS frame, and proceeds to S517.

[0205] (S517) The communication device performs control to enter a power save state.

[0206] That is, the power save control unit 303 of the communication device sets the state to the power save state.

[0207] (S518) The communication device waits until the NAV ends, and then ends the MU-RTS process.

[0208] Next, an example of the MU-RTS process of the opposing device 101, which is an AP, will be described.

[0209] FIG. 7 is a flowchart showing an example of MU-RTS processing of the opposing device 101 which is an AP according to the first embodiment of the present invention.

[0210] In this example, the Subfield defined in FIG. 8 is included in the MU-RTS Trigger frame.

[0211] Therefore, a field indicating whether a communication device that is an STA and has not been assigned a TXOP during the TXOP sharing period included in the MU-RTS Trigger frame will enter the power save state will be described below.

[0212] FIG. 8 is a diagram illustrating an example of a field indicating whether a communication device that is an STA that has not been assigned a TXOP during a TXOP sharing period included in the MU-RTS Trigger frame of the first embodiment enters a power save state.

[0213] As shown in FIG. 8, in this example, a subfield called Triggered TXOP sharing power save mode is defined.

[0214] If the value of the subfield is "0", it indicates that the STA must not enter the power save state during the TXOP sharing period, and if the value of the subfield is "1", it indicates that the STA may enter the power save state.

[0215] The subfield names are merely examples, and other names may be used. Furthermore, the correspondence between values ​​and states may be different as long as they can indicate the power save state.

[0216] This subfield may be included in the Common Info field or the User Info field of the MU-RTS Trigger frame.

[0217] Next, the MU-RTS process of the opposing device 101, which is an AP, will be described with reference to FIG.

[0218] This process is started in response to the opposite device 101, which is an AP, starting DL MU or Triggered TXOP sharing communication.

[0219] In the following description, the opposite device 101 that is an AP may be simply referred to as the opposite device 101.

[0220] (S700) The opposite device 101 determines whether the MU-RTS Trigger frame (TF) to be transmitted specifies TXOP sharing, and if it specifies it, proceeds to S703, and if it does not specify it, proceeds to S701.

[0221] (S701) The opposite device 101 transmits an MU-RTS Trigger frame, and after receiving a CTS frame from a communication device that is an STA performing DL MU communication, proceeds to S702.

[0222] (S702) Then, the opposite device 101 performs communication processing of the DL MU data, and when the communication processing is finished, ends the MU-RTS processing.

[0223] (S703) The opposite device 101 determines whether there is a possibility of communication with a communication device that is a STA to which a TXOP has not been allocated during the TXOP sharing period, and if there is a possibility, proceeds to S705, and if there is no possibility, proceeds to S704.

[0224] For example, if communication with a STA to which a TXOP has been allocated ends earlier than expected, and the opposing device 101 wishes to communicate with a communication device that is a STA to which a TXOP has not been allocated, it will proceed to S705, assuming that there is a possibility of communication.

[0225] (S704) The opposite device 101 sets the Triggered TXOP sharing Power save mode to “1” because there is no possibility of communicating with a communication device that is a STA to which a TXOP has not been allocated during the TXOP sharing period.

[0226] As a result, as explained above, a communication device that is an STA that has not been assigned a TXOP during the TXOP sharing period is allowed to enter the power save state.

[0227] (S705) On the other hand, if the process proceeds to S705, there is a possibility that the opposite device 101 will communicate with a communication device that is a STA to which a TXOP has not been allocated during the TXOP sharing period.

[0228] Therefore, the opposite device 101 sets the Triggered TXOP sharing power save mode to "0".

[0229] As described above, this prevents a communication device that is an STA that has not been assigned a TXOP during the TXOP sharing period from entering the power save state.

[0230] (S706) The opposite device 101 transmits an MU-RTS Trigger frame, receives a CTS frame from the communication device that is the STA to which the TXOP has been allocated, and proceeds to S707.

[0231] (S707) The opposite device 101 determines whether the data communication of the communication device, which is the STA to which the TXOP has been allocated, has ended.

[0232] In other words, it determines whether data communication between the opposite device 101 and a communication device that is a STA that has allocated a TXOP, or data communication between a communication device that is a STA that has allocated a TXOP and another communication device that is a STA that has not allocated a TXOP, has ended.

[0233] If the data communication has ended, the process proceeds to S710, and if the data communication has not ended, the process proceeds to S708.

[0234] For example, one example of a method for determining whether data communication has ended is to consider that data communication has ended if the opposing device 101 is unable to receive data transmitted by a communication device, which is a STA that has allocated a TXOP, for a certain period of time.

[0235] (S708) The opposite device 101 determines whether the TXOP sharing period has ended, and if it has ended, proceeds to S714, and if it has not ended, proceeds to S709.

[0236] (S709) If necessary, the opposite device 101 performs data communication with the communication device that is the STA to which the TXOP has been allocated, and returns to S707 again.

[0237] If it is not necessary, the process returns to S707.

[0238] (S710) If S707 is Yes and the process proceeds to S710, this means that the TXOP sharing period has not ended and there is remaining time in the TXOP sharing period, as can be seen from the determination in S708 as to whether the TXOP sharing period has ended.

[0239] In this case, the opposite device 101 first determines whether or not the Triggered TXOP sharing power save mode has been set to "1."

[0240] If set to "1", even if there is data addressed to a communication device that is a STA to which no TXOP has been assigned, the communication device will not send the data because it is in a power save state.

[0241] Therefore, the opposite device 101 proceeds to S714 so as not to send data during the TXOP sharing period.

[0242] On the other hand, if it is set to "0", the process proceeds to S711.

[0243] (S711) The opposite device 101 determines whether there is data addressed to a communication device that is another STA to which a TXOP has not been allocated. If there is no data, the opposite device 101 proceeds to S714; if there is data, the opposite device 101 proceeds to S712.

[0244] (S712) The opposite device 101 determines whether the TXOP sharing period has ended, and if so, proceeds to S714, and if not, proceeds to S713.

[0245] (S713) The opposite device 101 performs data communication with another STA, which is a communication device to which no TXOP has been assigned, and returns to S711 again.

[0246] (S714) The opposite device 101 communicates with other STAs, which are communication devices to which no TXOP has been allocated, as necessary during the remaining TXOP period, and then ends the MU-RTS process.

[0247] Note that there may be cases where the process proceeds to S714 before the TXOP sharing period has ended (for example, S710 returns Yes), in which case the process may wait until the TXOP sharing period ends before proceeding to S714.

[0248] As described above, a communication device functioning as an STA in the first embodiment does not maintain the Awake state during the TXOP sharing period, but enters the Listen state or Power save state, which consumes less power than the Awake state.

[0249] Therefore, compared to maintaining the Awake state during the TXOP sharing period, it is possible to reduce unnecessary power consumption.

[0250] Second Embodiment Next, a communication device functioning as an STA according to a second embodiment of the present invention will be described.

[0251] FIG. 9 is a flowchart showing an example of MU-RTS processing of a communication device functioning as a STA according to the second embodiment of the present invention.

[0252] Similarly to the first embodiment, FIG. 9 also shows an example in which the subfield defined in FIG. 8 is included in the MU-RTS Trigger frame.

[0253] The flowchart in Figure 9 can be understood as a flowchart when one of the communication devices 102 to 104, which are STAs, is the main focus, and as in the past, when there is no need to distinguish between them, they may simply be referred to as communication devices.

[0254] This process is started in response to a communication device functioning as a STA receiving an MU-RTS Trigger frame.

[0255] (S801) The communication device determines whether the received MU-RTS Trigger frame specifies TXOP sharing, and if it specifies it, proceeds to S802, and if it does not specify it, proceeds to S817.

[0256] As explained above, TXOP sharing can be specified in the Triggered TXOP Sharing Mode subfield included in the Common Info field of the MU-RTS Trigger frame.

[0257] (S802) Next, the communication device determines whether or not a TXOP has been allocated to itself, and if so, proceeds to S810, and if not, proceeds to S803.

[0258] (S803) The communication device receives a CTS frame from a communication device that is a STA to which a TXOP has been allocated, and proceeds to S804.

[0259] (S804) The communication device sets the NAV based on the Duration information included in the MU-RTS Trigger frame or the CTS frame, and proceeds to S805.

[0260] (S805) Next, the communication device determines whether the Triggered TXOP sharing power save mode included in the MU-RTS trigger frame is “0”.

[0261] That is, it is determined whether the subfield of the Triggered TXOP sharing power save mode is "0".

[0262] The communication device also determines whether the Triggered TXOP Sharing Mode is "2."

[0263] That is, it is also determined whether the subfield of the Triggered TXOP Sharing Mode is "2".

[0264] If both determinations are Yes, S805 becomes Yes and the process proceeds to S806, and if at least one of the determinations is No, S805 becomes No and the process proceeds to S813.

[0265] As explained above, if the Triggered TXOP sharing Power save mode subfield is "0", it indicates that the Power save state should not be entered during the TXOP sharing period.

[0266] Also, if the Triggered TXOP Sharing Mode subfield is "2", there is a possibility of data communication with a communication device that is another STA to which a TXOP has been allocated.

[0267] Therefore, if S805 is Yes, it is necessary to be in at least the Listen state.

[0268] Note that if at least one of the determinations is Yes, S805 becomes Yes and the process proceeds to S806, and if both determinations are No, S805 becomes No and the process proceeds to S813.

[0269] (S806) The communication device performs control to enter the Listen state.

[0270] That is, the power save control unit 303 of the communication device sets the state to the listen state.

[0271] (S807) The communication device determines whether the TXOP sharing period has ended, and if so, proceeds to S816, and if not, proceeds to S808.

[0272] (S808) The communication device determines whether or not a data frame has been received during the TXOP sharing period from the opposite device 101 which is an AP, or from another communication device which is a STA to which a TXOP has been allocated.

[0273] If the communication device has not received a data frame, the process returns to S807, and if the communication device has received a data frame, the process proceeds to S809.

[0274] (S809) The communication device performs data communication with the opposite device 101, which is the AP that has canceled the NAV and transmitted the data frame, or with another communication device that is a STA to which a TXOP has been allocated, and returns to S807.

[0275] (S810) On the other hand, if S802 is Yes, that is, if the TXOP is allocated to the communication device itself, the communication device transmits a CTS frame as a response to the opposite device 101, which is the AP, and proceeds to S811.

[0276] (S811) The communication device determines whether the TXOP sharing period has ended, and if it has ended, proceeds to S816, and if it has not ended, proceeds to S812.

[0277] (S812) The communication device performs data communication with the opposite device 101, which is an AP, or with another communication device, which is a STA, using the acquired TXOP (the TXOP allocated to the communication device).

[0278] For example, if the communication device 102 is a STA to which a TXOP is assigned, the communication device 102 performs data communication with the opposite device 101, which is an AP, or with communication devices 103 and 104, which are other STAs.

[0279] When the data communication is completed, the process returns to S811, and the TXOP sharing period will eventually end, so the process proceeds to S816.

[0280] (S813) As explained above, if the determination in S805 is Yes, the communication device needs to be in at least the Listen state. Conversely, if the determination in S805 is No, the communication device may be in the Power save state.

[0281] Therefore, the communication device performs control to enter the power save state.

[0282] That is, the power save control unit 303 of the communication device sets the state to the power save state.

[0283] (S814) The communication device waits until the TXOP sharing period ends, and proceeds to S815.

[0284] That is, the communication device waits until the NAV set in S804 ends, and then proceeds to S815.

[0285] (S815) When the TXOP sharing period ends, there is a possibility that data will be received from the opposite device 101 which is an AP or a communication device which is a STA to which a TXOP has been allocated.

[0286] Therefore, the power save control unit 303 of the communication device performs control to enter the Listen state, and the process proceeds to step S816.

[0287] That is, the power save control unit 303 of the communication device sets the state to the Listen state, and the process proceeds to S816.

[0288] (S816) If the communication device receives data from the opposite device 101, which is the AP, during the remaining TXOP period, the communication device performs data communication with the opposite device 101.

[0289] Here, the communication device is in the Awake state while transmitting a response frame such as a BA frame to the AP, and once this is completed, it returns to the Listen state again.

[0290] Furthermore, the communication device may transition from the Listen state to the Awake state when it receives a predetermined frame from the opposite device 101, which is an AP, or from a communication device, which is another STA, to which a TXOP has been allocated.

[0291] The specified frame is a frame for notifying that the opposing device 101, which is an AP, or a communication device, which is a STA that has been assigned a TXOP, will transmit a frame containing data, or a frame for notifying the start of a frame exchange sequence, etc.

[0292] For example, it may be an initial control frame.

[0293] The predetermined frame may also be a frame for notifying that another STA, which is a communication device that has been allocated a TXOP, will give up at least a portion of the allocated TXOP, such as a Null QoS frame.

[0294] Then, the communication device that receives the predetermined frame may receive a series of data, transmit a response frame such as a BA frame in response to the received data, and then return to the Listen state again.

[0295] (S817) On the other hand, if S801 is No, that is, if the MU-RTS Trigger frame received by the communication device does not specify TXOP sharing, the communication device performs the determination of S817.

[0296] Specifically, the communication device determines whether or not it is the destination of DL MU (Down Link Multi User) communication, and if it is the destination, proceeds to S818, and if it is not the destination, proceeds to S820.

[0297] (S818) The communication device transmits a CTS frame as a response to the opposite device 101, which is the AP.

[0298] (S819) The communication device communicates DL MU data with the opposite device 101, which is the AP, and when the DL MU data communication process is completed, ends the MU-RTS process.

[0299] (S820) On the other hand, if the result of S817 is No, the communication device receives a CTS frame from another communication device that is the destination of the DL MU communication, and proceeds to S821.

[0300] That is, if the communication device itself is not the destination of DL MU (Down Link Multi User) communication, the communication device receives a CTS frame from another communication device that is the destination of DL MU communication, and proceeds to S821.

[0301] For example, if the communication device 102 is the communication device 102 and the communication device that is the destination of the DL MU communication as another STA is the communication device 103, the communication device 102 receives a CTS frame from the communication device 103 that is the destination of the DL MU communication, and proceeds to S821.

[0302] (S821) The communication device sets the NAV based on the Duration information included in the MU-RTS Trigger frame or the CTS frame, and proceeds to S822.

[0303] (S822) The communication device performs control to enter a power save state.

[0304] That is, the power save control unit 303 of the communication device sets the state to the power save state.

[0305] This is because when the process reaches S822, the communication device does not receive data during DL MU communication.

[0306] (S823) Then, the communication device waits until the NAV ends, and then ends the MU-RTS process.

[0307] As described above, even in the second embodiment, a communication device functioning as an STA does not maintain the Awake state during the TXOP sharing period, but enters the Listen state or Power save state, which consumes less power than the Awake state.

[0308] Therefore, compared to maintaining the Awake state during the TXOP sharing period, it is possible to reduce unnecessary power consumption.

[0309] <<Other Embodiments>> A storage medium storing program code of software that realizes the above-described functions may be supplied to a system or device, and a computer (CPU, MPU) of the system or device may read and execute the program code stored in the storage medium.

[0310] In this case, the program code itself read from the storage medium will realize the functions of the above-described embodiments, and the storage medium storing the program code will constitute the above-described device.

[0311] 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.

[0312] In addition, not only can the above-mentioned functions be realized by the computer executing the program code it has read, but the OS running on the computer can also perform some or all of the actual processing based on the instructions of the program code to realize the above-mentioned functions.

[0313] OS is an abbreviation for Operating System.

[0314] Furthermore, the program code read from the storage medium is written into a memory provided on a function expansion board inserted into the computer or a function expansion unit connected to the computer.

[0315] Then, based on the instructions of the program code, a CPU provided in the function expansion board or function expansion unit may perform some or all of the actual processing to realize the above-mentioned functions.

[0316] The present invention can also be realized by supplying a program that realizes one or more functions of the above-mentioned embodiments to a system or device via a network or storage medium, and having one or more processors in the computer of that system or device read and execute the program.

[0317] It can also be realized by a circuit (for example, an ASIC) that realizes one or more functions.

[0318] As described above, the present invention is not limited to the above-described embodiments, and modifications and improvements to the embodiments are also included within the technical scope of the invention, which will be clear to those skilled in the art from the description of the claims.

[0319] The present invention is not limited to the above-described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to apprise the public of the scope of the present invention.

[0320] This application claims priority based on Japanese Patent Application No. 2024-110703, filed on July 10, 2024, the entire contents of which are incorporated herein by reference.

[0321] 101 Opposite device (AP) 102, 103, 104 Communication device (STA) 201 Storage unit 202 Control unit 203 Functional unit 204 Input unit 205 Output unit 206 Communication unit 301 TXOP sharing processing unit 302 NAV setting unit 303 Power save control unit 304 MU-RTS Trigger frame processing unit 305 Frame transmission / reception unit

Claims

1. A communication device functioning as an STA that performs wireless communication with a counterpart device functioning as an AP conforming to the IEEE802.11 series standard, comprising: a receiving means capable of receiving an MU-RTS TXS Trigger frame indicating TXOP sharing, which shares a part of a TXOP, from the counterpart device, and a CTS frame that is a response to the MU-RTS TXS Trigger frame; a period acquiring means for acquiring a TXOP sharing period set based on Duration information of the MU-RTS TXS Trigger frame or the CTS frame; and a state transition means for controlling transition of a startup state, wherein the state transition means acquires the TXOP sharing period set based on Duration information of the MU-RTS TXS Trigger frame in the MU-RTS TXS Trigger frame.

10. A communication device comprising: a communication device configured to control a communication device to enter a listen state during a TXOP sharing period when the communication device is not assigned a TXOP during the TXOP sharing period; 2. The communication device according to claim 1, wherein the MU-RTS TXS Trigger frame includes information indicating whether a communication device functioning as a STA to which a TXOP has been allocated during the TXOP sharing period will transmit an MPDU addressed to another communication device functioning as a STA, and the state transition means controls to enter a Listen state during the TXOP sharing period in accordance with the information indicating whether an MPDU will be transmitted when a TXOP has not been allocated to the communication device itself.

3. The communication device according to claim 1 or 2, characterized in that the MU-RTS TXS Trigger frame includes information indicating whether a communication device functioning as an STA that has not been assigned a TXOP during the TXOP sharing period may enter a power save state, and the state transition means controls the communication device to enter a listen state during the TXOP sharing period in accordance with the information indicating whether the communication device may enter a power save state when the communication device has not been assigned a TXOP.

4. A communication device as described in any one of claims 1 to 3, characterized in that when in the Listen state during the TXOP sharing period, the state transition means controls to enter the Awake state during the period in which a response frame is transmitted in response to a frame received from the opposite device or a communication device functioning as a STA to which a TXOP has been assigned.

5. A communication device as described in any one of claims 1 to 4, characterized in that when a predetermined frame is received from the opposite device or a communication device functioning as a STA to which a TXOP has been assigned while in the Listen state during the TXOP sharing period, the state transition means controls to enter an Awake state.

6. The communication device according to claim 5, characterized in that the specified frame is a frame for notifying that the opposite device or a communication device functioning as a STA to which the TXOP has been assigned will transmit a frame containing data.

7. The communication device according to claim 5, wherein the predetermined frame is a frame for notifying that a communication device functioning as a STA to which the TXOP has been allocated will give up at least a portion of the allocated TXOP sharing period.

8. A program for causing a computer to function as the communication device according to any one of claims 1 to 7.

9. A communication method for a communication device functioning as an STA that performs wireless communication with an opposite device functioning as an AP conforming to the IEEE802.11 series standard, comprising: a receiving step of receiving from the opposite device an MU-RTS TXS Trigger frame indicating TXOP sharing for sharing a portion of the TXOP, or a CTS frame that is a response to the MU-RTS TXS Trigger frame; a period acquisition step of acquiring a TXOP sharing period that is set based on Duration information of the MU-RTS TXS Trigger frame or the CTS frame; and, if a TXOP is not allocated to the opposite device during the TXOP sharing period in the MU-RTS TXS Trigger frame, acquiring the TXOP. and a state transition step of entering a Listen state during the sharing period.

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