Communication device, control method, and program

Abstract

A communication device for performing wireless communication, said device comprising a transmission control means for performing control for transmitting, to another communication device, a frame including an information element in which information indicating whether a second Listen mode is supported is stored, the second Listen mode being a Listen mode in which a power consumption amount when a Listen operation, which is an operation of waiting for communication, is performed is suppressed in comparison with power consumption when the Listen operation is performed in a first Listen mode, and the second Listen mode allowing the Listen operation to be performed under conditions where, with respect to at least one of the number of communication links, a bandwidth, a spatial stream, and a Modulation and Coding Scheme (MCS), the power consumption is expected to be lower than that in the first Listen mode.

Description

Communication device, control method, and program

[0001] The present disclosure relates to a communication device for communicating data.

[0002] In recent years, with the increase in the amount of data being communicated, the development of communication technologies such as wireless local area networks (LANs) has been progressing. The IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard series is known as the main communication standard for wireless LANs. The IEEE 802.11 standard series includes standards such as IEEE 802.11a / b / g / n / ac / ax.

[0003] Techniques that utilize sleep, intermittent operation, etc. to reduce the power consumption of communication devices are also being considered. For example, Patent Literature 1 discloses a procedure for achieving power saving by coordinating in advance the wake-up times of the devices between an access point (AP) and a station (STA), performing communication during the wake-up times, and reducing power consumption at other times.

[0004] Also, the IEEE802.11be standard, which is the successor to IEEE802.11ax, is being formulated. Furthermore, the UHR (Ultra High Reliability) Task Group is also studying the specifications of the IEEE802.11bn standard, which is the successor to IEEE802.11be.

[0005] Special table 2016-511600 publication

[0006] Meanwhile, the 802.11be standard attempts to improve communication rates compared to previous standards. Also, attempts have been made to incorporate a multi-link operation function that uses multiple communication links for high-speed data transmission and redundant transmission. Communication devices using new functions such as the multi-link operation function may receive data over multiple links, multiple spatial streams, wide bandwidths, and high MCS (Modulation and Scheme). Therefore, it is generally necessary to control the signal receiving circuit and antenna so that signals of all patterns can be received even in an idle state waiting for reception. The new functions that are the highlights of these standards are certainly useful in terms of increasing communication speed and reliability, contributing to an improved user experience. However, there is a problem in that the power required to properly operate a communication device increases not only during communication but also when waiting for communication. As such, in recent communication devices, even standby power consumption when waiting for communication, such as waiting for reception, has become non-negligible.

[0007] The present disclosure has been made in consideration of at least one of the above-mentioned problems. One aspect of the present disclosure aims to provide a specific mechanism for more actively reducing power consumption during standby. Specifically, a new function is provided that actively reduces power consumption during standby by selectively using an operation mode in which multiple communication conditions, such as a small number of links, a small number of streams, and a low MCS, are customized for power saving, and a normal operation mode. Hereinafter, for the sake of explanation, this new function will also be referred to as a low power listen function. Another aspect of the present disclosure aims to provide a mechanism that enables appropriate operation of the new low power listen function by making it possible to communicate in advance whether the function is supported.

[0008] A communication device according to one aspect of the present disclosure is a communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, and has a transmission control means that controls the transmission to another communication device of a frame that includes an information element that stores information indicating whether the communication device supports a second listen mode in which the listen operation, which is an operation of waiting for communication, can be performed under conditions that are expected to consume less power than the first listen mode in terms of at least one of the number of communication links, bandwidth, spatial streams, and Modulation and Coding Scheme (MCS), in order to reduce the amount of power consumed when the listen operation is performed compared to the power consumed when the listen operation is performed in a first listen mode.

[0009] According to one aspect of the present disclosure, it is possible to provide a mechanism for more actively reducing standby power consumption. Also, according to another aspect of the present disclosure, it is possible to appropriately operate the function by notifying in advance whether the mechanism is supported.

[0010] 1 is a diagram showing an example of the configuration of a communication system. FIG. 2 is a diagram showing an example of the hardware configuration of a communication device (AP / STA). FIG. 3 is a diagram showing an example of the functional configuration of a communication device (AP / STA). FIG. 4 is a sequence diagram showing the procedure of an LPL (Low Power Listen) function. FIG. 5 is an example of an information element for notifying whether LPL is supported. FIG. 6 is an example of an information element for notifying whether LPL is supported. FIG. 7 is an example of an information element for notifying LPL operation information. FIG. 8 is an example of a frame when operation information is notified by an action frame. FIG. 9 is an example of an ICF. FIG. 10 is an example of a response to an ICF. FIG. 11 is a flowchart showing an example of STA control. FIG. 12 is a flowchart showing an example of AP control. FIG. 13 is a flowchart showing an example of STA control. FIG. 14 is a transition diagram of operation modes and operation states for explaining the LPL function.

[0011] 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.

[0012] 1 shows an example of the configuration of a communication system according to this embodiment. The communication system according to this embodiment includes one access point device (hereinafter simply referred to as an AP, AP STA, or access point) and one station device (hereinafter simply referred to as an STA, Non-AP STA, or station).

[0013] The AP 101 and the STA 102 are configured to be able to communicate wireless frames conforming to the IEEE802.11bn standard, which is the successor to the IEEE802.11be standard and targets a maximum transmission speed of 46.08 Gbps.

[0014] IEEE stands for Institute of Electrical and Electronics Engineers. IEEE 802.11bn, the successor standard to IEEE 802.11be, has high reliability, low latency, and improved throughput during congestion as its main features. One of the goals of 802.11bn is to reduce power consumption in APs. Wireless frames communicated under this successor standard are also called UHR (Ultra High Reliability) PPDUs. PPDU stands for Physical Layer Protocol Data Unit.

[0015] The name UHR was chosen for convenience, taking into account the goals and key features of the successor standard, and may be replaced with a different name once the standard is fully established. Similarly, the name IEEE 802.11bn may be replaced with a different name once the standard is fully established. Note that this specification and the accompanying claims essentially apply to all successor standards to the 802.11be standard. Furthermore, the AP 101 and STA 102 may also transmit wireless frames corresponding to legacy standards that predate the IEEE 802.11bn standard. Examples of legacy standards include the IEEE 802.11a / b / g / n / ac / ax / be standards.

[0016] The AP 101 and the STA 102 communicate by exchanging wireless signals in frequency bands such as the 2.4 GHz band, the 3.6 GHz band, the 5 GHz band, the 6 GHz band, and the 45 GHz band and 60 GHz band known as millimeter waves. The frequency bands used by the AP 101 and the STA 102 are not limited to these and may be, for example, the Sub 1 GHz band. The AP 101 and the STA 102 may communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, 640 MHz, 1080 MHz, and 2160 MHz. The bandwidth used by the communication device 100 is not limited to these and may be, for example, 240 MHz, 4 MHz, etc. The IEEE 802.11 series standard specifies a frequency channel using a 20 MHz bandwidth as a basic channel in frequency bands such as 2.4 GHz, 5 GHz, and 6 GHz. This standard also defines multiple available channels in each of the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. This standard also allows a channel to be used in combination with an adjacent channel. In this embodiment, the use of a channel in combination with an adjacent channel is referred to as channel bonding. Furthermore, a channel bundle formed by one or two or more adjacent channels is referred to as a communication link. In other words, a link formed by combining two 20 MHz-bandwidth channels uses a 40 MHz bandwidth. The AP 101 is an access point that supports a multi-band function that provides networks on multiple different frequency channels. In this embodiment, the AP 101 is illustrated as a dual-band access point that provides a 2.4 GHz-band network and a 5 GHz-band network.

[0017] STA 102 establishes one or more links between STA 102 and AP 101 to communicate data with AP 101 or another communication device. For example, STA 102 executes a connection procedure with AP 101 to establish a link with AP 101. When the connection procedure between STA 102 and AP 101 is completed, a link is established between the devices. Establishing the link enables communication device 100 to access a wireless medium and communicate data, etc., with the other communication device.

[0018] Furthermore, the AP 101 and STA 102 of this embodiment can establish multiple links between devices and perform multi-link communication. Hereinafter, a communication link is also simply referred to as a link. The AP 101 that performs multi-link communication is also referred to as an AP MLD (AP multi-link device) 101, and the STA 102 that performs multi-link communication is also referred to as a non-AP MLD 102. For example, the AP 101 can establish a link with the STA 102 in a 2.4 GHz band network and communicate. In addition, the AP 101 and the STA 102 can establish a second link in the 5 GHz band in parallel and communicate. In this case, the STA 102 performs multi-link communication, utilizing two links to communicate. STA 102 can perform STR (Simultaneous transmit and receive) operation with AP 101, which allows STA 102 to simultaneously receive on link 1 and transmit on link 2. In other words, STR communication can be performed. STA 102 can also perform NSTR operation with AP 101, which is constrained by the requirement to either use all links for transmission simultaneously or use all links for reception simultaneously. NSTR stands for Nonsimultaneous transmit and receive. NSTR operation is used when the frequency distance between links is close and mutual interference occurs.

[0019] For example, when link 1 using a bandwidth of 160 MHz and link 2 using a bandwidth of 80 MHz are established between devices, communication device 100 performs communication using the channels that make up the links. The link using a bandwidth of 160 MHz is configured by bundling eight channels with a bandwidth of 20 MHz. The link using a bandwidth of 80 MHz is configured by bundling four channels with a bandwidth of 20 MHz.

[0020] Furthermore, the AP 101 and the STA 102 can communicate using multiple spatial streams to communicate more efficiently with other communication devices. That is, SU-MIMO (Single User Multi-Input Multi-Output) communication at 2SS and 4SS can be performed. Also, MU-MIMO (Multi-User Multi-Input Multi-Output) communication at 2SS to 16SS can be performed. In SU-MIMO communication and MU-MIMO communication, the actual communication rate can be increased in proportion to the number of streams. Note that multiple spatial streams can also be used to increase reliability. Furthermore, in order to transmit information at a higher density in modulation, communication can be performed using BPSK, QPSK, 16QAM, 64QAM, 256QAM, 1024QAM, 4096QAM, etc. MCS (Modulation and Coding Scheme) indicates the combination of the modulation method and the modulation scheme such as the code rate as an index, and communication device 100 can select any MCS from MCS0 to MCS15 and perform communication.

[0021] As described above, communication devices such as the STA 102 communicate via multiple links using the MLO function described above, and receive data with the multiple spatial stream counts, wide bandwidth, and high MCS described above. Therefore, it is generally necessary to control the signal receiving circuit and antenna so that signals of all patterns can be received, even in an idle state waiting for reception. Utilizing these functions is certainly useful in terms of increasing communication speed and reliability, and contributes to improving the user experience. However, there is also the problem that the power required to properly operate a communication device increases not only during communication but also in an idle state waiting for communication to begin. As such, in today's communication devices, even standby power consumption when waiting for reception has become non-negligible.

[0022] In view of this, this embodiment provides a specific mechanism for more actively reducing power consumption during standby. Specifically, an LPL function is newly provided, which communicates using communication parameters customized for power saving under multiple communication conditions, such as supporting only a small number of links, a small number of streams, and a low MCS. LPL stands for Low Power Listen. The LPL function actively reduces power consumption during standby by selectively using LPL Enabled Mode and Active Mode, which is the normal operating mode. Hereinafter, for the sake of explanation, this new function will also be referred to as the Low Power Listen function. In addition, a mechanism is provided that allows the appropriate operation of the Low Power Listen function by making it possible to communicate in advance whether or not the function is supported.

[0023] First, the concept of the LPL function will be explained using FIG. 13 . FIG. 13 shows a transition diagram of the operation modes of a communication device to explain the LPL function. Communication devices such as the AP 101 and the STA 102 support an Active Mode, which corresponds to normal operation, and an LPL Enabled Mode, in which the LPL function, which actively reduces power consumption during standby, is enabled. The communication devices such as the AP 101 and the STA 102 operate in one of a plurality of operation modes, including at least the above two operation modes. Note that in this embodiment, the Active Mode is also referred to as the LPL Disabled Mode or the LPL Disabled State. The Active Mode can also be considered a normal mode in which communication can be performed under normal communication conditions agreed upon between the AP and the STA. A communication device such as STA102 operating in this Active Mode can perform multi-link communication, communication using multiple streams, communication using wide bandwidths such as 80 MHz, 160 MHz, and 320 MHz, and communication using a high MCS with the AP 101. When switching the operating mode, the communication device such as STA102 notifies the opposing device such as AP 101 that it will switch modes. An Action frame can be used for this notification.

[0024] A communication device such as the STA 102 that has transitioned to the LPL Enabled Mode operates in either the NPCS or LPCS state. NPCS stands for Normal Power Communication State, and LPCS stands for Low Power Listen Communication State.

[0025] A communication device such as STA102 operating in an operating state called NPCS can perform high-speed and / or highly reliable communication under normal communication conditions agreed upon between the AP and the STA, similar to Active Mode. The STA102 transitions its operating state to LPCS when a predetermined time has elapsed since the end of data communication with the outside world, or when it transmits a frame indicating an intention to terminate communication, such as a CF-End signal indicating the end of a transmission opportunity. LPCS is an operating state that is expected to reduce power consumption. When transitioning to the LPCS operating state, a communication device such as STA102 switches its operating settings to a communication condition customized to reduce power consumption associated with standby for communication, such as one link, one spatial stream, a 20 MHz bandwidth, and a low MCS. Due to its characteristic of being able to maintain a state capable of two-way communication with low power consumption, in this embodiment, the state in which two-way communication in LPCS is being performed or is capable of being performed is also referred to as a Low Power Awake state. In other words, the Low Power Awake state is a state in which the device operates with lower power consumption than a state in which bidirectional communication is possible or possible in Active Mode or an NPCS operating state. In this embodiment, the communication conditions with restrictions when operating in LPCS are also referred to as Low Capability. The normal communication conditions when operating in NPCS in Active Mode or LPL Enabled Mode are also referred to as High Capability.

[0026] A communication device such as STA102 operating in the LPCS operating state transitions the operating state of the communication device to NPCS in accordance with its own wishes or upon receiving a frame from an AP such as AP101, which is an opposing communication device, conveying that it wishes to communicate in a normal state.

[0027] In this way, a communication device such as the STA 102 operating in the LPL enabled mode selectively uses the NPCS and LPCS as the operation state of the communication device. For example, during normal operation, the STA transitions to the NPCS to enable high-speed communication, and during standby, the STA transitions to the LPCS to reduce power consumption. By selectively using these operation states, the STA operating in the LPL enabled mode can achieve both convenience and power saving.

[0028] 13 illustrates two modes, Active Mode and LPL Enabled Mode, as examples of multiple operation modes, but the present invention is not limited to these. Naturally, communication devices such as STA 102 can also support operation in other operation modes, such as previously known Scheduled PS mode and Unscheduled PS mode. Communication devices such as STA 102 operating in Scheduled PS mode or Unscheduled PS mode have a long Doze state period and enter an Awake state only during periods when a DTIM (delivery traffic indication message) is transmitted to monitor the presence of uplink data. During operation in PS mode, communication devices such as STA 102 maintain a Doze state almost entirely, except for extremely short Awake state periods. During this Doze state, a communication device such as STA102 stops supplying power to a circuit for communication. By performing these controls, it is possible to reduce the average power consumption during the period when the communication device is operating in the PS mode. Note that when operating in the Awake state in these PS (Power Saving) modes, a Low Power Awake state may be used. A communication device such as STA102 operating in these PS modes transitions its operation mode to LPL Enabled Mode or Active Mode based on its own preference or the DTIM reception status. The operation mode to transition to may be determined based on past communication performance, etc. In this way, power consumption is reduced by appropriately switching between multiple operation modes depending on the communication status, etc. Other operation modes may include EMLSR (Enhanced Multi-Link Single Radio) mode, etc.

[0029] In summary, the LPL Enabled Mode in which the LPL function of this embodiment is enabled can be said to be a mode with lower average power consumption than the Active Mode. Also, the LPL Enabled Mode has higher average power consumption than the Scheduled / Unscheduled PS Mode, but can be said to be a mode with high communication convenience, such as being able to execute small data communications at any time.

[0030] A specific mechanism for switching the above modes will be described in detail using Figure 2 and subsequent figures. While Figure 1 shows a communication system consisting of one AP 101 and one STA 102 as an example, the number of STAs constituting the communication system may be greater than that shown. Furthermore, STAs that support only the aforementioned legacy standard and do not support the LPL function can also be connected to the network of AP 101 to form a communication system.

[0031] The AP 101 and the STA 102 may also be configured to support wireless communication based on other communication standards, such as Bluetooth (registered trademark), NFC, and Bluetooth (registered trademark) Low Energy (LE). NFC stands for Near Field Communication. The AP 101 and the STA 102 may also be configured to support wired communication using an Ethernet cable or wired communication using optical fiber. Specific examples of the AP 101 include, but are not limited to, a wireless LAN router and a personal computer (PC). The AP 101 and the STA 102 may also be information processing devices, such as wireless chips, that support the transmission and reception of UHR PPDUs. In this case, various controls may be performed by hardware circuits within the wireless chip. Various processes may also be performed by cooperation between a processor, memory, and hardware circuits, such as an ASIP, within the wireless chip. ASIP stands for Application-specific instruction set processor.

[0032] Specific examples of the STA 102 include cameras, printers, tablets, smartphones, projectors, PCs, gaming devices, video cameras, smart glasses, wearable devices such as head-mounted displays, etc. Other examples include IoT devices such as sensor nodes, network video cameras, etc., but are not limited to these.

[0033] 2 shows an example of the hardware configuration of the communication device (AP 101, STA 102). The communication device includes, as an example of the hardware configuration, 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.

[0034] The storage unit 201 is configured with ROM and / or RAM, and stores various information such as programs for performing various operations described below and communication parameters for wireless communication. RAM stands for Random Access Memory, and ROM stands for Read Only Memory. Note that the storage unit 201 may be a storage medium such as a non-volatile storage device, such as a hard disk or SSD (Solid State Drive), in addition to memories such as ROM and RAM.

[0035] The control unit 202 is configured with, for example, a processor such as a CPU or MPU, an ASIC (application-specific integrated circuit), a DSP (digital signal processor), an FPGA (field programmable gate array), etc. Here, CPU stands for Central Processing Unit, and MPU stands for Micro Processing Unit. The control unit 202 executes programs stored in the storage unit 201 and controls the entire device by operating hardware circuits such as the ASIC. Note that the control unit 202 may control the entire device in cooperation with the programs stored in the storage unit 201 and an OS (operating system).

[0036] The control unit 202 also controls the functional unit 203 to perform predetermined processes such as capturing images, printing, and projection. The functional unit 203 is hardware that enables the device to perform predetermined processes. For example, if the communication device is a camera such as a digital still camera or a smartphone equipped with a camera, the functional unit 203 is an imaging unit that captures images of the surroundings via a camera unit (not shown) included in the communication device. For example, if the communication device is a printer, the functional unit 203 is a printing unit that performs printing on a sheet such as paper based on print data obtained from the outside via wireless communication. For example, if the communication device is a projector or smart glasses, the functional unit 203 is a projection unit that performs projection of image data or video data obtained from the outside via wireless communication. In the case of smart glasses, the projection surface is the end user's retina, for example. The data processed by the functional unit 203 may be data stored in the storage unit 201 or data communicated with another AP or STA via the communication unit 206 (described later). Furthermore, communication devices such as AP 101 can also provide network storage functions such as NAS (Network Attached Storage). This function is provided to other communication devices as a web service such as a network storage service. For example, a communication device such as an STA connects to a network storage service provided by AP 101 using a protocol such as SMB over QUIC. The communication device such as an STA then uploads files to the storage service and downloads files from the storage. This upload and download data communication is also achieved by communicating UHR PPDU between devices. SMB stands for Server Message Block, and QUIC stands for Quick UDP Internet Connections.

[0037] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user. Here, the output by the output unit 205 includes, for example, at least one of display on a screen, audio output by a speaker, and vibration output. Note that both the input unit 204 and the output unit 205 may be implemented by a single module, such as a touch panel. The output unit 205 functions as a display means for presenting information to the user. The input unit also functions as a reception means for receiving user operations.

[0038] The communication unit 206 controls wireless communications compliant with the IEEE 802.11 standard series and IP communications. In this embodiment, the communication unit 206 cooperates with the antenna 207 to execute communication control for transmitting and receiving UHR PPDUs, which are wireless frames of the UHR standard, and PPDUs conforming to earlier standards. The multiple antennas 207 are, for example, antennas capable of transmitting and receiving signals in at least one frequency band of the sub-GHz band, 2.4 GHz band, 5 GHz band, 6 GHz band, and millimeter wave band. While FIG. 2 illustrates an example in which the AP 101 and the STA 102 of this embodiment each have three antennas, this is not limiting and more or fewer antennas may be used.

[0039] If the communication device is compatible with the aforementioned NFC standard, Bluetooth standard, wired communication standard, or the like, the communication unit 206 may be configured to control wireless communication or wired communication in accordance with these communication standards. The communication units 206 of the AP 101 and the STA 102 each have a hardware circuit that decodes or encodes signals communicated over each link. Each antenna and hardware circuit is configured to enable individual power control. Alternatively, the communication unit may be configured to have a separate communication unit corresponding to each link.

[0040] Next, the functional configuration of the AP 101 and the STA 102 will be described with reference to Fig. 3. The communication devices such as the AP 101 and the STA 102 have functional units such as a frame processing unit 301, a mode control unit 302, an RX / TX control unit 303, a frame transmission / reception unit 304, and a UI control unit 305.

[0041] The mode control unit 302 cooperates with each functional unit and each hardware unit to realize the above-mentioned control of the operation mode and connection control with the opposing device. Specifically, the connection process involves authentication processing, association processing, and 4-way handshake processing to establish a communication link with the opposing communication device. In the case of AP 101, the opposing device is a STA such as STA 102, and in the case of STA 102, the opposing device is an AP such as AP 101. The control unit 302 also manages communication parameters to be used in each operation mode. When switching the operation mode, the control unit 302 requests the RX / TX control unit 303 to switch the communication conditions using the communication parameters it manages. Upon receiving the switching request, the control units 303 and 304 control the communication unit 206 and multiple antennas 207 to switch the communication conditions required for transmission and reception.

[0042] The frame processing unit 301 generates and analyzes signals (frames) when communicating with a partner communication device. The frame processing unit 301 generates management frames for the communication device to execute a connection procedure and control frames for controlling communication. The management frames generated and analyzed by the processing unit include Beacon, Probe Request, Probe Response, Association Request, Association Response, FIS (Fast Initial Link Setup) Discovery, and Action. Authentication Request and Authentication Response frames are also included. The processing unit 301 also generates and analyzes other management frames of the IEEE 802.11 standard series as appropriate, but due to space limitations, a description thereof will be omitted.

[0043] The control frames generated and analyzed by the processing unit also include frames that transition the operational state of the LPL function when the function is enabled. For example, they also include frames that prompt the opposing device, whose operational state is LPCS, to transition to NPCS. For convenience of explanation, these frames are referred to as ICFs (Initial Communication Frames). The frames generated and analyzed by the processing unit also include ICF Responses, which are responses to the ICFs. The management frames generated by the frame processing unit 301 are, of course, not limited to these. The frame processing unit 301 also generates data frames and QoS (Quality of Service) data frames based on instructions from upper-level applications (not shown). The frame processing unit 301 generates information elements such as UHR Capabilities elements and UHR Operation elements defined in the IEEE 802.11 series standards. It is also possible to generate UHR Protected action frames for the LPL function.

[0044] The UHR Capabilities element can include an information element indicating whether the communication device 100 has the capability to execute the LPL function. Furthermore, the elements in the UHR Protected action frame can include information elements for negotiating whether to enable the LPL function, etc. Details of these elements will be described later.

[0045] The frame transmitting / receiving unit 304 performs transmission processing of wireless frames generated by the frame processing unit 301 and reception processing of wireless frames from the other device. The received digital data obtained by the reception processing is transferred to the processing unit 301. The processing unit 301 analyzes the received digital data transferred from the transmitting / receiving unit 304 and, depending on the analysis results, generates an appropriate response frame or notifies an upper layer (not shown) of the analyzed data (such as IP data included in the payload). The frame transmitting / receiving unit 304 cooperates with each unit to perform transmission control for transmitting frames and reception control for receiving frames.

[0046] The UI (User Interface) control unit 305 provides a setting screen as a UI for the user to input communication-related settings. The UI control unit 305 also accepts user operations on the setting screen via the input unit 204 and stores the settings in the storage unit 201 as operation settings of the communication device. The UI control unit 305 accepts a setting change operation to enable or disable the LPL function via a setting screen (not shown). The UI control unit 305 also stores in the storage unit 201 a user setting of whether to enable or disable the LPL function corresponding to the setting change operation. The operation settings will be referred to as appropriate in the flowcharts described below.

[0047] <LPL Execution Procedure> Next, a procedure for using the LPL function between the AP 101 and the STA 102 will be described with reference to Fig. 4. Fig. 4 is a sequence diagram showing the procedure for executing the LPL function between the AP 101 and the STA 102.

[0048] First, the STA 102 performs a connection process with the AP 101 (F401). The connection process will now be described. The AP 101 periodically broadcasts information necessary for other communication devices (such as the STA 102) to connect to the AP 101 using a beacon frame or a FILS Discovery frame. The STA 102 recognizes surrounding APs such as the AP 101 by receiving the beacon or FILS Discovery and initiates a wireless connection procedure. Note that if the AP 101 does not transmit a beacon or if the STA 102 fails to properly receive a beacon transmitted by the AP 101, the STA 102 may initiate a wireless connection procedure without receiving a beacon. For example, the STA 102 may initiate a wireless connection procedure using connection information such as a service set identifier (SSID) or a passphrase registered in advance by a user or the like. To connect to AP 101, STA 102 first transmits a Probe Request frame to AP 101. Upon receiving the Probe Request, AP 101 transmits a Probe Response frame addressed to STA 102. When connecting via Multi-Link, the Probe Request and Probe Response may be transmitted and received separately as an ML Probe Request and an ML Probe Response. Upon receiving the Probe Response, STA 102 transmits an Authentication Request frame to AP 101. When the AP 101 receives the Authentication Request frame, it transmits an Authentication Response frame to the STA 102. Each Authentication frame may be transmitted and received twice. When the STA 102 receives the Authentication Response frame, it transmits an Association Request frame. When the AP 101 receives the Association Request frame, it transmits an Association Response frame. Through these steps, a connection procedure is performed between the AP 101 and the STA 102, and a link using a wireless medium is established between the AP 101 and the STA 102.After the above connection procedure, the AP 101 and the STA 102 may execute a 4-way handshake or the like to exchange security information. The AP 101 and the STA 102 may also execute a wireless connection procedure using a method other than the above.

[0049] The AP 101 and the STA 102 exchange capability information by including an information element indicating capability information indicating whether or not the AP 101 and the STA 102 support the Low Power Listen mode in at least one frame used in the wireless connection procedure.

[0050] Specifically, in a wireless connection procedure, the AP 101 and the STA 102 share capability information indicating whether the Low Power Listen mode is supported with the other communication device. The AP 101 and the STA 102 also share information that can identify the link, bandwidth, spatial stream, MCS, etc., to be used when executing Low Power Listen with the other communication device. In this embodiment, information for identifying optional functions supported by the communication device in wireless communication is called capability information.

[0051] Specific examples of capability information exchanged in the wireless connection procedure will be described with reference to Figures 5A and 5B. As an example, the capability information is transmitted to the other device using the UHR Capabilities element shown in Figure 5A. Figure 5A shows an example of the UHR Capabilities element included in a frame for performing the wireless connection procedure.

[0052] The UHR Capabilities element is included in the above-mentioned Beacon, Probe Request, Probe Response, Association Request, Association Response, etc. In other words, the UHR Capabilities element is an information element that conveys capability information indicating whether optional functions of the 802.11bn standard are supported.

[0053] The UHR Capabilities element includes an Element ID field 501, a Length field 502, and an Extended Element ID field 503. The UHR Capabilities element further includes an LPL (Low Power Listen) Support field 504. Note that the UHR Capabilities element also includes fields indicating whether other optional capability information is supported. For example, a field indicating whether UORA (uplink OFDMA-based random access)-based low latency channel access is supported may be included.

[0054] The type of element is indicated by a combination of the Element ID field 501 and the Extended Element ID field 503. In this embodiment, as an example, an element with 255 specified in field 501 and 138 specified in field 503 is defined as a UHR Capabilities element. However, this is not limited to this. Other combinations can also be defined as UHR Capabilities elements. The Length field 502 indicates the length of the element shown in FIG. 5A. The LPL (Low Power Listen) Support field 504 stores a value indicating whether the communication device transmitting the frame supports the Low Power Listen function. Storing "1" in this field indicates that the communication device transmitting the frame supports the Low Power Listen function. Storing "0" in this field indicates that the communication device transmitting the frame does not support the Low Power Listen function. Note that "0" can also be modified to mean that the Low Power Listen function is not supported or that the function is disabled. In other words, it can also be modified to mean that the function is disabled.

[0055] Field 504 may be included in a subfield included in a UHR Capabilities element. For example, it is assumed that field 504 is included in a UHR MAC Capabilities Information field. However, field 504 is not limited to this, and may also be included in an EHT PHY Capabilities Information field. Field 504 may also be defined as a field within a field that conveys other capability information.

[0056] FIG. 5B is a modified example of the UHR Capabilities field. The difference from FIG. 5A is that the LPL capability information is subdivided into an LPL Tx Support field 514 indicating transmission capabilities and an LPL Rx Support field 515 indicating reception capabilities. The AP must be able to transmit an ICF to an LPCS STA in order to transition the STA's operational state. Therefore, AP 101 must set the LPL Tx Support field 514 to 1. Setting this field by the AP means that it supports control of transmitting an ICF with the number of streams / MCS / links that an LPCS STA in the operational state can properly receive. STAs such as STA 102 may set the LPL Tx Support field 514 to 1. Furthermore, STAs such as STA 102 must set the LPL Rx Support field 515 to 1. Additionally, an AP such as AP 101 may set the LPL Rx Support field 515 to 1.

[0057] That is, in the modified example, field 514 indicates whether or not the device has the ability to transmit frames while maintaining the operating state of the LPCS, and field 515 indicates whether or not the device has the ability to receive data while maintaining the operating state of the LPCS.

[0058] It should be noted that elements including fields similar to fields 504, 514, and 515 in FIGS. 5A and 5B can also be configured to include frames different from the frames used in the wireless connection procedures described above.

[0059] The AP 101 and the STA 102 enable or disable the LPL function based on the capability information indicating whether the LPL function is supported or acquired from each other, or on the communication status. In other words, the AP 101 and the STA 102 switch their own operation mode to the Active Mode or the LPL Enabled Mode described with reference to FIG. 13 .

[0060] In this embodiment, when the operating state of a STA such as STA 102 is set to LPCS in LPL Enabled Mode, it is assumed that one specific link is used to listen for frames from the AP. However, this is not limited to this, and the number of links when operating in LPCS may be multiple. For example, if the number of links when operating in NPCS is three, it is sufficient to reduce the number of links when operating in LPCS to two, as long as the number of links is reduced compared to when operating in NPCS. That is, this embodiment assumes that the number of communication links in LPCS is reduced compared to NPCS or Active Mode. Furthermore, the number of links may be the same when the operating state is LPCS and when operating in NPCS. In this case, when transitioning to LPCS, two or more other communication conditions, such as MCS and number of spatial streams, may be customized for power saving, thereby reducing power consumption during standby.

[0061] An AP such as AP 101 can transmit detailed information about operation parameters to be used by a STA operating in LPL Enabled Mode to the STA in advance using the UHR Operation element shown in FIG.

[0062] FIG. 6 shows an example of a UHR Operation element included in a frame used by the AP 101 for wireless connection procedures.

[0063] By including the elements shown in FIG. 6 in a frame used for wireless connection procedures, AP 101 transmits two or more communication conditions to be used when operating in an operating state such as LPCS to a counterpart device such as STA 102. Specifically, AP 101 appropriately determines the link to listen on when a subordinate STA operates in LPCS with the LPL function and the communication parameters to be used in LPCS. Then, AP 101 transmits Beacon, Probe Response, and Association Response frames including a UHR Operation element containing the determined communication parameters. Note that the UHR Operation element may be included in only one of the listed frames. The UHR Operation element may also be included in other frames.

[0064] 6 shows an example of a UHR Operation element. The UHR Operation element includes an Element ID field 601, a Length field 602, and an Extended Element ID field 603. The UHR Operation element also includes a Padding Delay field 604, an MCS field 605, and a Listen Link field 606. The UHR Operation element further includes a Listen Interval field 607, a Listen Duration field 608, and a Listen Offset field 609. The Element ID field 601 and the Extended Element ID field 603 are fields for uniquely identifying the element. Therefore, a value different from the combination of 501 and 503 in FIGS. 5A and 5B is stored.

[0065] The Length field 602 stores the length of this element.

[0066] The Padding Delay field 604 stores the minimum MAC padding period that the AP 101 plans to include in the ICF. The MCS field 605 stores the upper limit of the MCS to be supported when the STA operates in LPCS. For example, an upper limit value indicating that only MCSs up to a lower QAM (e.g., 16-QAM, 64-QAM, 256-QAM, etc.) than the QAM (e.g., 4096-QAM) that can be used when operating in NPCS is stored. More specifically, this field allows an index value corresponding to the upper limit of the UHR-MCS expected to be used when operating in LPCS. For example, storing "7" indicates that the upper limit of the usable MCS is 64-QAM and a coding rate of 5 / 6. In other words, storing "7" limits the UHR-MCS usable when operating in LPCS to MCSs indicated by any of the index values ​​0 to 6.

[0067] The Listen Link field 606 is a field that stores a Link ID that indicates which Link should be used to wait for reception when operating in LPCS.

[0068] The Listen Interval field 607, Duration field 608, and Listen Offset field 609 are optional fields. These fields store parameters for enabling more power-saving reception standby. These fields are provided from the AP to the STA when optional control is performed to further achieve power saving effects by providing Low Power Awake and Doze states in the LPCS operating state. The Listen Interval field 607 indicates the interval at which the STA enters the Low Power Awake state, which allows communication at low power while operating in LPCS. For example, if the value is 100, the STA transitions to the Low Power Awake state every 100 ms. The Listen duration field 608 indicates how long the Low Power Awake state will last. For example, a value of 15 indicates that the Low Power Awake state will be maintained for 15 ms. The Listen offset field 609 indicates the time interval from beacon transmission to the Low Power Awake state. For example, a value of 20 indicates that this is the initial time of the loop in which the Low Power Awake state will be entered 20 ms after beacon transmission. STAs such as STA 102 determine the time to enter Awake and the time to enter Doze based on this parameter, and perform control to switch between Awake operation, in which communication is waited for in Low Capability, and Doze state based on the determined time. Therefore, even in the NPCS operating state, doze operation is possible for a certain period, enabling more adaptive power saving control. Other communication parameters may also be included. For example, parameters such as the number of spatial streams to be used in LPCS and parameters for the bandwidth to be used may be included.

[0069] Returning to the explanation of FIG. 4 , the sequence for enabling the LPL function will be explained. STA 102 transmits a frame for enabling LPL to AP 101. AP 101, having received the frame, transmits a response frame. STA 102, having received the response frame, transitions its operation mode to LPL Enabled Mode. Note that, in this embodiment, a case where the STA transitions to the above-mentioned LPCS operation state in response to reception of the response frame is illustrated as an example, but the present invention is not limited to this.

[0070] A frame for enabling the LPL will be described with reference to Fig. 7 . Fig. 7 shows an example of an Action field of an Action frame that notifies the enabling / disabling of Low Power Listen. In this embodiment, this field is called a Low Power Listen Mode Notification frame Action field. This is not limited to this, and this field may be called by another name. This field includes a Category field 701, a Protected UHR Action field 702, a Dialog Token field 703, and a Low Power Listen Control field 704. Furthermore, the Low Power Listen Mode Notification frame Action field may include a Low Power Listen Parameter Update field 705. The Category field 701 indicates the category of this Action field. For example, the Category field 701 stores an identification number corresponding to Protected UHR Action. The Protected UHR Action field 702 indicates the identifier of this Action field in the Protected UHR Action category. For example, the Protected UHR Action field 702 stores an identification number indicating the Low Power Listen Mode Notification frame Action field. The Dialogue Token field 703 indicates an identifier for executing a series of information exchanges between the AP 101 and the STA 102. For example, an identifier assigned by the requesting communication device is stored in the Dialogue Token field 703. The responding communication device stores the value contained in the received Dialogue Token field 703 in the Dialogue Token field 703 of the response frame and transmits it. Furthermore, the MAC frame in which the Action field of FIG. 7 is stored is referred to as an LPL Operating Mode Notification frame.

[0071] The Low Power Listen Control field 704 includes an LPL Mode field 711 and a Low Power Listen Parameter Update Control field 712. The LPL Mode field 711 indicates whether or not to use the LPL function. For example, when the STA 102 requests to start using the Low Power Listen function by itself, it stores a 1 in this field. On the other hand, when the STA 102 requests to stop using the LPL function, it stores a 0 in this field. Note that the LPL Mode field 711 may be configured to have two bits so that it can indicate whether or not to use the LPL function for transmission and reception, respectively. For example, if STA102 specifies 0 in the first bit and 1 in the second bit, the STA102 requests that it intends to use the receiving process during LPCS, but does not intend to use the transmitting process during LPCS.

[0072] The Low Power Listen Parameter Update Control field 712 indicates the presence or absence of the Low Power Listen Parameter Update field 705. For example, if the Low Power Listen Mode Notification frame Action field includes the Low Power Listen Parameter Update field 705, then a 1 is stored in this field. On the other hand, if the Low Power Listen Mode Notification frame Action field does not include the Low Power Listen Parameter Update field 705, then a 0 is stored in this field. The Low Power Listen Parameter Update field 705 includes a Padding Delay field 604, an MCS field 605, a Listen Link field 606, a Listen Interval field 607, a Listen duration field 608, and a Listen offset field 609. These fields have the same functions as the fields of the same names described in FIG. 6 , and therefore description thereof will be omitted. As in FIG. 6 , the field may also include parameters for the number of spatial streams to be used in the LPCS and parameters for the bandwidth to be used. When a STA such as STA 102 wants to customize the communication parameters of the LPCS, it transmits an Action frame to which the Low Power Listen Parameter Update field 705 has been added.

[0073] The AP 101 determines whether to use the LPL function based on the frame received from the STA 102. Specifically, the AP 101 acquires the value of the LPL Mode field 711 included in the UHR Protected action frame received from the STA 102, and determines the intention of the STA, such as the STA 102, which is the opposite device, based on the value.

[0074] The AP 101 responds to the STA 102 with a response frame that includes a Status Code in addition to the fields described in FIG. 7 . The STA 102 analyzes the value of the Status Code in the response frame and determines whether the request to use the LPL function has been accepted by the AP 101. If the request has been accepted by the AP 101, the STA 102 changes its own operating mode to the operating mode corresponding to the request. FIG. 4 illustrates an example in which the STA 102 requests to use the LPL function and the AP 101 accepts the request. The STA 102 updates its own communication parameters to those corresponding to the LPCS. Specifically, when the STA 102 communicates communication parameter update information using a frame of the Enabling sequence illustrated in F402, the STA 102 sets the communication parameters. On the other hand, if the STA 102 does not communicate updated information about the communication parameters in the enabling sequence, the STA 102 uses the UHR Operation element to set the communication parameters for the LPCS that were previously shared by the AP 101. Then, the STA 102 starts a process of waiting for frames in the LPCS.

[0075] Next, a state transition from LPCS to NPCS will be described. When the AP 101 determines that data to be transmitted to the STA 102 has occurred, the AP 101 transmits an ICF to the STA 102, which causes the STA 102 to change its operating state from LPCS to NPCS (F403).

[0076] Upon receiving the ICF transmitted in F403, the STA 102 transmits a response signal to the ICF (F404). Specific examples of the ICF and the response signal to the ICF will be described using Figures 8 and 9. The ICF frame is a type of control frame and includes a Frame Control field 801, a Duration field 802, an RA field 803, a TA field 804, and a Link Info List field 805. The Frame Control field 801 is a field that identifies the type of frame and includes a value indicating that the frame is an ICF frame for the LPL function. The Duration field 802 indicates the maximum duration of the NPCS initialized by the ICF frame. The STA that received the ICF frame transitions to a state in which it can receive frames with the parameters described in the Link Info List field during the reception standby period described in this field. The RA field 803 stores the MAC address of the STA 102, which indicates the receiver of the frame. MAC stands for Medium Access Control. The TA field 804 stores the MAC address of the AP 101, which indicates the sender of the frame. The Link Info List field 805 stores information specifying the link to be used in the NPCS state and one or more pieces of correspondence information that combine communication parameters for that link. When operating the STA in the NPCS operating state, if multiple links are enabled, the AP 101 stores multiple pieces of correspondence information in the List field 805. One piece of correspondence information consists of fields 811 to 815. The correspondence information will be explained in detail. The correspondence information includes a Link ID field 811, a BW field 812, an NSS field 813, an MCS field 814, and a Delay field 815. The Link Info List field 805 is information that identifies the link to be used by the NPCS. Fields 812 to 815 indicate communication parameters to be used when communicating over the link identified in 805. More specifically, the BW field 812 indicates the bandwidth to be used for communication.For example, values ​​of 0, 1, 2, 3, and 4 indicate that frames should be listened for or transmitted at 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz, respectively. The NSS field 813 indicates the number of spatial streams. For example, it indicates that frames should be listened for or transmitted at a spatial stream equal to the value indicated in the field plus 1. NSS stands for number of spatial streams. The MCS field 814 indicates the maximum MCS used for communication. The Delay field 815 specifies the grace period after transmitting the ICF frame until frame transmission is performed according to the specified parameters. Note that instead of 815, a padding field can be added to the end of the ICF frame for time adjustment. The ICF frame is transmitted on the link and bandwidth on which the STA 102 in the LPCS operating state is waiting for communication. On the other hand, in order to secure transmission rights on a different link that is expected to be used for communication after transitioning to the NPCS, an ICF may also be simultaneously transmitted to that different link.

[0077] Next, a response frame to the ICF will be described using FIG. 9 . FIG. 9 shows an example of an ICF Response frame. The ICF Response frame may include a Frame Control field 801, a Duration field 802, an RA field 803, a TA field 804, a Status Code field 901, and a Link Info List field 805. Fields that overlap with those in FIG. 8 are given the same numbers, and descriptions thereof will be omitted. The Status Code field 901 indicates whether communication is possible with a value specified by the ICF. It should be noted that a configuration may be adopted in which transmission of the ICF Response frame is omitted. Alternatively, a configuration may be adopted in which a CTS (Clear To Send) frame is returned instead of the ICF Response frame illustrated in FIG. 9 . At this time, the CTS frame may be returned every 20 MHz over all links and bandwidths specified by the ICF.

[0078] Next, the STA 102 starts frame standby processing in the NPCS. Specifically, the STA 102 updates its own communication parameters with the communication parameters included in the ICF, and starts frame standby with the communication parameters corresponding to hissu. That is, the STA 102 switches to a High Capability communication condition for high-speed communication and highly reliable communication.

[0079] After waiting for the grace period, the AP 101 transmits a data frame to the STA 102 (F405). The AP 101 transmits the data frame with transmission parameters corresponding to the HighCapability notified in F403.

[0080] Upon receiving the data frame, the STA 102 returns an Ack frame as a response frame to the received data frame (F406). The STA 102 and the AP 101 can transmit downlink data by repeating the sequences indicated in F405 and F406 during the grace period indicated in the Duration field of the ICF.

[0081] When the AP 101 determines that a series of data transmissions to the STA 102 has been completed, it transmits a CF-End frame or a QoS Null frame (F407). This frame functions as a frame that ends the NPCS operation state and prompts transition to the LPCS state. The frame that prompts transition to the LPCS is not limited to this, and other frames may also be used. For example, it may be a control frame newly defined for the LPL function. Upon receiving the CF-End frame or the QoS Null frame, the STA 102 changes its operation state back to LPCS. In other words, the STA 102 switches to a Low Capability communication condition, which intentionally limits functionality for power saving purposes.

[0082] 4 illustrates an example in which downlink communication is triggered by an ICF issued by AP 101. On the other hand, when STA 102 determines that it wishes to perform high-speed and / or highly reliable communication, such as when uplink data is generated, STA 102 determines communication conditions corresponding to NPCS and transitions to NPCS. After transitioning to NPCS, STA 102 performs a CCS (Clear Channel Assessment) using transmission parameters corresponding to the updated communication conditions, and transmits a CTS frame if it determines that it has won channel access. Then, when it receives an RTS (Request To Send) frame from AP 101 in response to the CTS frame, it may transmit a data frame. After completing a series of data transmissions and determining that it should switch its operating mode to LPCS, STA 102 transmits a CF-End frame. Instead of a CF-End frame, the STA 102 may transmit a QoS Null frame or a QoS Data frame in which the RDG / More PPDU subfield of the CAS Control field is set to 0. After transmitting this frame, the STA 102 transitions its operating state to LPCS. That is, the STA 102 switches to a Low Capability communication condition, which intentionally limits functionality.

[0083] Although omitted from Fig. 4 due to space limitations, STA 102 that has determined that the operating mode should be changed to Active Mode depending on the communication conditions, etc., transmits a request to disable the LPL to AP 101. Upon receiving this request, AP 101 transmits a response frame indicating that it has accepted the request to disable the LPL. In this LPL Disabling sequence, the LPL Disabling can be requested using the LPL Operating Mode Notification frame described with reference to Fig. 7. When requesting disabling, STA 102 stores 0 in the LPL Mode field included in the frame to request disabling.

[0084] <Communication Control Using LPL Function> Next, communication control using the LPL function of this embodiment will be described with reference to the flowcharts of FIGS.

[0085] 10 and 12 are flowcharts illustrating an example of communication control in the STA 102, and FIG. 11 is a flowchart illustrating an example of communication control in the AP 101.

[0086] Each process shown in the flowcharts of Figures 10 and 12 is executed by the processor of the control unit 202 of the STA 102 executing a computer program stored in the storage unit 201. Note that some processes, such as transmission and modulation, are realized by the processor of the control unit 202 in cooperation with various processors, ASICs, DSPs, FPGAs, etc., constituting the communication unit 206, and the ASICs, DSPs, FPGAs, etc., constituting the antenna and control unit 202. Note that this is not limited to this, and it is of course also possible to configure the communication unit 206 and the antenna to cooperate to execute each process shown in the flowcharts. Note that when it is desired to clearly indicate the subject of the process, the functional unit described in Figure 3 will be used as the subject. Note that the control indicated by the dotted lines is optional control, and does not necessarily need to be executed.

[0087] 11 is executed by the processor of the control unit 202 of the AP 101 executing a computer program stored in the storage unit 201. Note that some processes, such as transmission and modulation, are realized by the processor of the control unit 202 working in cooperation with the various processors, ASICs, DSPs, FPGAs, etc., that make up the communication unit 206, and the ASICs, DSPs, FPGAs, etc., that make up the control unit 202. Note that this is not a limitation, and it is of course also possible to configure the communication unit 206 and the antenna to work in cooperation to execute each process shown in the flowchart. Note that when it is desired to clearly indicate the subject of a process, the functional unit described in FIG. 3 will be used as the subject. Note that the control indicated by the dotted lines is optional and does not necessarily need to be executed.

[0088] First, the control of the STA 102 will be described with reference to Fig. 10. The processes shown in Fig. 10 are excerpts of a series of processes from when the STA 102 discovers an AP such as the AP 101 to when it decides whether to utilize the LPL mode. Fig. 12 excerpts the specific processes when it is decided to utilize the LPL function.

[0089] In S1000, the control unit 202 of the STA 102 determines whether to start a connection with an AP such as AP 101. If it is determined that the connection should be started, the process proceeds to S1001, and if it is not determined that the connection should be started, the process waits until a condition for determining that the connection with the AP should be started is met.

[0090] In S1001, the control unit 202 performs the connection process described in FIG. 4 and acquires AP capability information from a frame received from an AP, such as AP 101, for the connection process. Specifically, the control unit 202 acquires the capability information included in the UHR Capabilities element described above. The STA 102 then performs the connection process shown in FIG. 4 to complete the connection with the destination AP, such as AP 101. When the connection is completed, the LPL function is disabled, and the STA 102 operates in Active Mode. That is, the STA 102 starts operation with communication parameters that enable high-speed communication and / or highly reliable communication, corresponding to the High Capability negotiated with the AP during the connection process.

[0091] In S1002, the mode control unit 302 refers to the user setting for enabling or disabling the LPL function stored in the storage unit 201. Then, the control unit 302 determines whether the user setting has been made to disable the LPL function. If it is determined that the user setting has been made to disable the LPL function, the process proceeds to S1009. On the other hand, if it is determined that the user setting has not been made to disable the LPL function, the process proceeds to S1003.

[0092] In S1003, the mode control unit 302 determines whether the destination AP to which the STA 102 is connected supports the LPL function. Specifically, in S1001, it is determined that the LPL function is supported if 1 is specified in the LPL Support field 504 of the capability information acquired from the destination AP. As another example, it is determined that the LPL function is supported if 1 is specified in the LPL Tx Support field 514 of the acquired capability information. If it is determined that the LPL function is supported, the process proceeds to S1005, and if it is determined that the LPL function is not supported, the process proceeds to S1009.

[0093] In S1005, the mode control unit 302 determines whether an NSTR link for multi-link communication has been established with the destination AP. If it is determined that an NSTR link has been established, the process proceeds to S1009. If it is determined that an NSTR link has not been established, the process proceeds to S1006. More specifically, the control unit 302 determines that an NSTR has not been established when an STR link for multi-link communication has been established or when a single link has been established. In this embodiment, in the case of an NSTR link, there is a relationship with link synchronization control, etc., and because control of the transition to the NPCS becomes complicated, it is determined that the LPL function will not be used.

[0094] In S1006, the control unit 302 acquires the current remaining battery charge and a charging status indicating whether charging is in progress from an OS (not shown) that manages the operation of the STA 102. If the acquired remaining battery charge is equal to or less than a threshold and the charging status is not charging, the control unit 302 determines that the battery is in a low state and proceeds to S1010. On the other hand, if the acquired remaining battery charge is greater than a threshold or equal to or less than the threshold but the charging status is charging, the control unit 302 determines that the battery is not in a low state and proceeds to S1007. The battery threshold used for this determination can be, for example, 20%.

[0095] In S1007, the control unit 302 determines whether the communication quality with the AP 101 is equal to or lower than a threshold value. If it is determined that the communication quality with the AP 101 is equal to or lower than a predetermined threshold value, the process proceeds to S1009. If it is determined that the communication quality with the AP 101 is higher than the predetermined threshold value, the process proceeds to S1008.

[0096] In S1008, the control unit 302 determines whether a low-latency communication application is running. If it is determined that a low-latency communication application is running, the process proceeds to S1009. If it is determined that a low-latency communication application is not running, the process proceeds to S1010. This determination is made in cooperation with the OS that manages the running application (process). As another example, instead of this determination, it may be determined whether low-latency communication is required based on QoS parameters of IP packets received from the destination AP or IP packets sent to the destination AP. In this case, the control unit 303 may proceed to S1009 if it determines that low-latency communication is required.

[0097] In S1009, the control unit 303 determines not to use the LPL function and maintains operation in Active Mode. On the other hand, in S1010, the control unit 303 determines to use the LPL function and transitions the operation mode of the STA 102 to LPL Enabled Mode. Specific control when transitioning to LPL Enabled Mode will be described later with reference to FIG. 12.

[0098] Next, the control of the AP 101 will be described with reference to Fig. 11. Each control shown in Fig. 11 indicates a process that is executed after power is supplied to the AP 101, the startup sequence is completed, and normal operation as an AP is started.

[0099] In S1100, the frame processing unit 301 of the AP 101 determines whether data transmission to the STA of the NPCS is necessary. If it is determined that data transmission to the STA of the NPCS is necessary, the process proceeds to S1101. If it is not determined that data transmission to the STA of the NPCS is necessary, the process proceeds to S1107.

[0100] In S1101, the frame processing unit 301 identifies the traffic type and estimates the traffic volume required for data transmission to the destination STA determined to require data transmission in S1100. For example, the processing unit 301 identifies the traffic type into which the data is classified based on the QoS information of the data. Furthermore, for example, the processing unit 301 stores past communication records and compares the communication records with the characteristics of the data to be transmitted (e.g., data source information / destination information, etc.), thereby estimating the traffic volume, which is a characteristic of the traffic to be generated. Note that the estimation method is not limited to this.

[0101] In S1002, the processing unit 301 determines whether the estimated traffic should be communicated while maintaining the LPCS of the destination STA. If it is determined that the estimated traffic should be communicated while maintaining the LPCS of the destination STA, the processing proceeds to S1103. On the other hand, if it is not determined that the estimated traffic should be communicated while maintaining the LPCS of the destination STA (i.e., if it is determined that the LPCS should be transitioned to NPCS), the processing proceeds to S1104. For example, it determines whether the transmission time when transmitting the estimated traffic volume at the communication rate for communication while maintaining the LPCS will fit within a predetermined time. If it is determined that it will fit within the predetermined time, it determines that the estimated traffic should be communicated while maintaining the LPCS of the destination STA.

[0102] In S1103, the processing unit 301 cooperates with the RXTX control unit 303 to set, as transmission parameters, LPCS communication parameters corresponding to the destination STA for the communication unit 206 and the antenna 207. Next, the processing unit 301 cooperates with the transceiver unit 304, the communication unit 206, and the antenna 207 to transmit data using the LPCS communication parameters. When the data transmission is complete, the communication parameters are updated to normal communication parameters, and the process proceeds to S1100.

[0103] Meanwhile, in S1104, the processing unit 301 cooperates with the other units to transmit the ICF described in FIG. 8 to the destination STA. At this time, the processing unit 301 cooperates with the mode control unit 302 to determine communication parameters to be used when the destination STA transitions to the NPCS, based on the traffic characteristics (traffic type and traffic volume) identified and estimated in S1101. At this time, the mode control unit 302 also manages the determined communication parameters and operating state as current state information associated with the destination STA. In other words, the control unit 302 updates the operating state included in the state information corresponding to the destination STA from the LPCS to the NPCS, and stores the communication parameters used in the NPCS as state information. The processing unit 301 then transmits an ICF including, in field 805, communication conditions corresponding to the determined communication parameters.

[0104] In S1105, the processing unit 301 cooperates with the control units 302 and 303, the transmission / reception unit 304, the communication unit 206, and the antenna 207 to wait for the transition time to the NPCS, and then transmits data to the destination STA using the communication parameters notified by the ICF. If the processing unit 301 determines that transmission of a series of traffic data to the destination STA has been completed based on the data accumulation status in the transmission buffer, etc., the processing proceeds to S1106.

[0105] In S1106, the processing unit 301 transmits a CF-End frame or a QoS Null frame in response to the completion of a series of traffic transmissions. Then, the processing unit 301 instructs the mode control unit 302 to update the operation state of the destination STA to LPCS. Upon receiving this instruction, the control unit 302 updates the operation state included in the state information corresponding to the destination STA from NPCS to LPCS.

[0106] In S1107, the mode control unit 302 determines whether enabling / disabling of the LPL is necessary between the STA and the mode control unit 302. Specifically, when the control unit 302 receives an LPL Operating Mode Notification frame in cooperation with each unit, the control unit 302 determines whether enabling / disabling of the LPL is necessary for a specific STA based on the communication status. For example, the control unit 302 can determine that enabling of the LPL is necessary for an STA in Active Mode where the data transmission frequency has decreased. Furthermore, for example, the control unit 302 can determine that disabling of the LPL is necessary for an STA in LPL Enabled Mode where a large amount of downlink data or low latency data has occurred. This means that, based on the communication status known to the AP, the AP determines that the operation mode of a particular STA that is not / is estimated to become incompatible with the current operation mode should be changed.

[0107] If it is determined that the LPL enabling / disabling is necessary, the process proceeds to S1108, and if it is not determined that the LPL enabling / disabling is necessary, the process proceeds to S1109.

[0108] In S1108, the control unit 302 cooperates with each unit to execute the LPL enabling / disabling procedure. Specifically, when the control unit 302 cooperates with each unit to receive an LPL Operating Mode Notification frame, the control unit 302 transmits a response frame. In addition, the mode control unit 302 updates information indicating the operation mode of the STA to which the response frame is sent to the new operation mode.

[0109] Furthermore, if the AP determines that the operation mode of a specific STA should be changed, it transmits an LPL Operating Mode Notification frame corresponding to the determination result to request the specific STA to change the operation mode. Then, upon receiving a response frame, the mode control unit 302 updates the information indicating the operation mode of the STA that sent the response frame to the new operation mode.

[0110] On the other hand, in S1109, the control unit 202 determines whether to stop the AP operation. If it is determined that the AP operation should be stopped, the series of processes ends. If it is determined that the AP operation should not be stopped, the process proceeds to S1110. For example, the control unit 202 can determine to stop the AP operation when it receives a user operation to press a shutdown button or a power button (not shown).

[0111] In S1110, the control unit 202 executes other communication control. Specifically, it performs the connection control described in FIG. 4 and communication control with STAs in Active Mode and STAs whose operating state is NPCS. As described above, a STA whose operating state is LPCS may spontaneously transition to the operating state of NPCS and perform data communication with an AP using communication parameters corresponding to High Capability. When the control unit 302 receives data using communication parameters corresponding to High Capability from a STA whose currently managed state information is LPCS, it updates the operating state of the STA that transmitted the data. That is, it updates the operating state included in the currently managed state information of the source STA from LPCS to NPCS.

[0112] Finally, communication control in a STA such as the STA 102 that has transitioned to the LPL enabled mode will be described with reference to FIG.

[0113] In S1200, the mode control unit 302 of the STA 102 executes the LPL enabling procedure in cooperation with the processing unit 301 and the frame transmission / reception unit 304. Specifically, the mode control unit 302 transmits an LPL Operating Mode Notification frame in which "1" is stored in the LPL Mode. Upon receiving a normal response to the frame, the mode control unit 302 changes the transmission and reception parameters for LPCS in cooperation with the RX / TX control unit 303, the communication unit 206, and the antenna 207. If the LPL Operating Mode Notification frame includes a field 705, the transmission and reception parameters are changed to those corresponding to the parameters indicated in the field 705. If the field 705 is not included in the LPL Operating Mode Notification frame, the transmission and reception parameters are changed to those shared in advance by the destination AP such as the AP 101 using the UHR Operation element.

[0114] In S1201, the processing unit 301 cooperates with each unit to determine whether a frame addressed to itself has been received. If it is determined that a frame addressed to itself has been received, the process proceeds to S1202, and if it is determined that a frame addressed to itself has not been received, the process proceeds to S1203.

[0115] In S1202, the processing unit 301 determines whether the received frame is an ICF of an LPL. If it is determined that the received frame is an ICF of an LPL, the processing proceeds to S1207. If it is not determined that the received frame is an ICF of an LPL, the processing proceeds to S1206. The ICF of an LPL is, for example, the frame described in FIG. 8.

[0116] In S1203, the processing unit 301 determines whether data transmission to the AP is necessary. If it is determined that data transmission to the AP is necessary, the process proceeds to S1204. If it is determined that data transmission to the AP is not necessary, the process proceeds to S1210.

[0117] In S1204, the processing unit 301 identifies and estimates traffic characteristics. The specific processing content is the same as the processing in S1101 described in the AP side control, and therefore a description thereof will be omitted.

[0118] In S1205, the mode control unit 302 determines whether communication should be performed while maintaining the LPCS for the traffic identified and estimated in S1204. If it is determined that communication should be performed while maintaining the LPCS for the traffic, the process proceeds to S1206. If it is determined that communication should be performed while maintaining the LPCS for the traffic, the process proceeds to S1207. For example, it determines whether the transmission time when transmitting the estimated traffic volume at a communication rate for communication while maintaining the LPCS falls within a predetermined time. If it is determined that the transmission time falls within the predetermined time, it determines that communication should be performed with the estimated traffic while maintaining the LPCS of the destination STA.

[0119] In S1206, the control unit 202 cooperates with each unit to execute data communication using LPCS communication parameters. In the case of data reception processing, the control unit 202 receives frames using the set LPCS reception parameters and analyzes and processes the payload of the received frames as appropriate. In the case of data transmission processing, the control unit 202 generates and transmits frames including data to be transmitted using the set LPCS reception parameters. When data communication using LPCS is completed, the control unit 202 advances the process to S1210.

[0120] In S1207, the mode control unit 302 cooperates with each unit to change the communication parameters to High Capability for NPCS. If an ICF has not been received, the communication parameters are set to those used in Active Mode agreed upon in the connection process. If an ICF has been received, the communication parameters are changed to those stored in the ICF.

[0121] In S1208, the control unit 202 executes data communication using the changed communication parameters. In the case of data transmission, the control unit 202 executes data transmission using the changed NPCS transmission parameters, and in the case of data reception, executes data reception using the changed reception parameters. When the series of data communications is completed, the control unit 202 advances the process to S1209.

[0122] In S1209, the mode control unit 302 communicates a CF-End / QoS Null frame in cooperation with each unit. After communicating the frame, the mode control unit 302 changes the communication parameters to those corresponding to LowCapability for LPCS in cooperation with each unit.

[0123] In S1210, the mode control unit 302 determines whether disabling of the LPL function is necessary. Specifically, the mode control unit 302 determines whether disabling is necessary based on a determination similar to the determinations described in S1005 to S1008 above. That is, the mode control unit 302 determines that disabling is necessary when any of the following conditions is met: the remaining battery charge has dropped below a threshold, the communication link has been re-set up to an NSTR link pair, or the communication quality is below a predetermined threshold. The mode control unit 302 also determines that disabling is necessary when a low-latency communication application is running. The mode control unit 302 also determines that disabling is necessary based on a determination similar to the determination described in S1002, that is, when a user setting is changed during operation in LPL Enabled Mode to disable the LPL function. If it is determined that disabling of the LPL function is necessary, the process proceeds to S1211; if it is not determined that disabling of the LPL function is necessary, the process proceeds to S1201.

[0124] In S1211, the mode control unit 302 executes the LPL disabling procedure in cooperation with each unit. Subsequently, the mode control unit 302 changes the communication parameters for transmission and reception to communication parameters corresponding to High Capability for Active Mode in cooperation with each unit. The changed parameters are assumed to be communication parameters for Active Mode that were negotiated in advance during the connection process.

[0125] <Variation 1> In the above-described embodiment, a case has been exemplified in which a frame including a UHR Operation element or an LPL Operating Mode Notification frame is used to notify the MCS, number of spatial streams, and the like used in the LPCS operating state. However, this is not limited to this. It is also possible to configure the system to notify only information identifying the link corresponding to 606, and to use specified communication parameters for other communication parameters. The default communication parameters may be, for example, communication parameters that use one spatial stream, a minimum MCS for receiving control frames such as ICF, and only the primary 20 MHz bandwidth. A specific example will be described. STA 102 operates as a Non-AP MLD, and in Active Mode, performs multi-link communication established with AP 101. One of the links also utilizes MIMO communication, and communication with a high MCS and a 160 MHz bandwidth is also possible. In this state, when the STA 102 receives the LPL Operating Mode Notification, the STA 102 changes the condition to one in which communication is possible with a 20 MHz bandwidth over one link identified by the link ID, and also changes the condition to one in which communication is performed with one spatial stream number without using MIMO or the like.

[0126] <Modification 2> In the above embodiment, the ICF frame includes communication parameters to be used after transitioning to the NPCS, but this is not limiting. For example, the transmission of the communication parameters may be omitted. In this case, a configuration may be adopted in which default communication parameters are used when returning to the NPCS. For example, the default communication parameters may be the communication parameters used when operating in the Active Mode negotiated in the connection process.

[0127] <Variation 3> Note that the information on whether the LPL function is supported, which is included in the UHR Capabilities element illustrated in Figures 5A and 5B, can also be configured to be included in the Multi-Link element. For example, a new field such as Extended MLD Capabilities is provided in the Common Info field of the Basic Multi-Link element of the Multi-Link element. This field may then be configured to include information equivalent to 504, 514, or 515. This element can be included in MAC frames such as an ML Probe Request, an ML Probe Response, or a Beacon.

[0128] <Another embodiment 1> The disclosure of this embodiment also includes the following configuration.

[0129] (Configuration 1) A communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, characterized in that the communication device has a transmission control means that controls the transmission of a frame to another communication device, the frame including an information element that stores information indicating whether the second mode, in which at least two or more conditions of the number of communication links, bandwidth, and spatial streams are changed to conditions that are estimated to consume less power than the first mode, in order to reduce the amount of power consumption when waiting for communication compared to the amount of power consumption when waiting for communication in the first mode.

[0130] (Configuration 2) The communication device according to Configuration 1, wherein the transmission control means transmits the information to another communication device by including the information element in a Beacon frame or an Association Response frame and transmitting the frame.

[0131] (Configuration 3) The communication device according to configuration 1 or 2, wherein the transmission control means transmits the information to another communication device by including the information element in at least an Association Request frame and transmitting the frame.

[0132] (Configuration 4) The communication device described in any one of configurations 1 to 3, characterized in that the transmission control means transmits the frame in which information indicating that the second mode is supported is stored in the information element, and after establishing a link for communication with another communication device, if the other communication device is operating in the first mode, it transmits information regarding activation to the second mode to the other communication device, and then changes the two or more conditions to conditions estimated to consume less power than the first mode, and transitions the operation mode of the communication device to the second mode.

[0133] (Configuration 5) The communication device according to Configuration 4, wherein the communication device is a Non-AP (Access Point) MLD (Multi-Link Device), and when operating in the first mode, can establish multiple links with the other communication device to perform STR communication, and the transition means changes the operating mode to a condition where communication can be performed with the other communication device via one link with a bandwidth of 20 MHz and with one spatial stream number, and transitions the operating mode to the second mode.

[0134] (Configuration 6) The communication device according to any one of configurations 1 to 5, wherein the information element is an information element included in a UHR MAC Capabilities Element or a UHR PHY Capabilities Element.

[0135] (Configuration 7) The communication device according to any one of configurations 1 to 6, wherein the information element can store 1 or 0, where 1 indicates that the second mode is supported and 0 indicates that the second mode is not supported or that the second mode is disabled.

[0136] (Configuration 8) The communication device according to any one of configurations 1 to 7, wherein the frame in which the information element is stored is at least one of a Beacon frame, a Probe Request frame, a Probe Response frame, an Association Request frame, an Association Response frame, a ReAssociation Request frame, a ReAssociation Response frame, and an Action frame.

[0137] (Configuration 9) A communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, comprising a transmission control means that transmits a frame that causes a transition to the first mode to another communication device that is operating in a second mode waiting for communication while changing at least two or more conditions of the number of communication links, bandwidth, and spatial streams to conditions that are estimated to consume less power than the first mode, in order to reduce the amount of power consumption when waiting for communication compared to the amount of power consumption when waiting for communication in a first mode, and the transmission control means further transmits information to the other communication device that identifies the link to be used in the second mode.

[0138] (Configuration 10) The communication device according to configuration 9, wherein the transmission control means transmits the frame including information indicating the two or more conditions.

[0139] (Configuration 11) The communication device described in Configuration 10 further comprises a determination means for determining the two or more conditions when operating the other communication device in the second mode depending on the communication status with the other communication device, and the transmission control means transmits the determined two or more conditions to the other communication device.

[0140] (Configuration 12) A control method for a communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, characterized by comprising a transmission control step of controlling the transmission of a frame to another communication device, the frame including an information element that stores information indicating whether the second mode, in which the second mode is supported, is supported, in which at least two or more conditions of the number of communication links, bandwidth, and spatial streams are changed to conditions that are estimated to consume less power than the first mode, in order to reduce the amount of power consumed when waiting for communication compared to the amount of power consumed when waiting for communication in the first mode.

[0141] (Configuration 13) A control method for a communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, characterized in that the control method for the communication device includes a first transmission control step of transmitting information to another communication device operating in a second mode awaiting communication in a state in which at least two or more conditions of the number of communication links, bandwidth, and spatial streams are changed to conditions estimated to consume less power than the first mode, in order to reduce the amount of power consumption when awaiting communication compared to the amount of power consumption when awaiting communication in the first mode, to cause the device to transition to the second mode and information identifying the link to be used in the second mode.

[0142] (Configuration 14) A program for causing a computer to execute the method for controlling a communication device according to configuration 12 or 13.

[0143] The present invention can also be realized by a process in which a program that realizes one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., an ASIC) that realizes one or more of the functions.

[0144] 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.

[0145] This application claims priority based on Japanese Patent Application No. 2024-057554, filed on March 29, 2024, the entire contents of which are incorporated herein by reference.

[0146] 101 AP MLD 102 non-AP MLD 206 Communication Department

Claims

1. A communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, characterized in that the communication device has a transmission control means that controls the transmission to another communication device of a frame that includes an information element that stores information indicating whether the second listen mode is supported, which is a listen mode for reducing power consumption when performing listen operation, which is an operation of waiting for communication, compared to power consumption when performing the listen operation in a first listen mode, and which enables the listen operation to be performed under conditions that are expected to consume less power than the first listen mode in terms of at least one of the number of communication links, bandwidth, spatial streams, and Modulation and Coding Scheme (MCS).

2. The communication device according to claim 1, wherein the transmission control means transmits the information to another communication device by including the information element in a Beacon frame or an Association Response frame and transmitting the frame.

3. The communication device according to claim 1, wherein said transmission control means transmits said information to another communication device by including said information element in at least an Association Request frame and transmitting the frame.

4. The communication device according to claim 1, characterized in that the transmission control means transmits the frame in which information indicating that the second Listen mode is supported is stored in the information element, and after establishing a link for communication with another communication device, if the other communication device is operating in the first Listen mode, the transmission control means transmits information regarding the activation of the second Listen mode to the other communication device, and then changes at least one condition of the number of communication links, bandwidth, spatial streams, and MCS to a condition estimated to have less power consumption than the first Listen mode, and transitions the operation mode of the communication device to the second Listen mode.

5. The communication device according to claim 4, wherein the communication device is a Non-AP (Access Point) MLD (Multi-Link Device) and, when operating in the first Listen mode, is capable of establishing multiple links with the other communication device to perform STR communication, and the transition means changes the condition between the communication device and the other communication device to a condition in which communication can be performed with one link having a bandwidth of 20 MHz and with one spatial stream number, and transitions the operation mode to the second Listen mode.

6. The communication device according to claim 1, wherein the information element is an information element included in a UHR MAC Capabilities Element or a UHR PHY Capabilities Element.

7. The communication device according to claim 1, characterized in that the information element can store 1 or 0, where 1 indicates that the second listen mode is supported and 0 indicates that the second listen mode is not supported or that the second listen mode is disabled.

8. The communication device according to any one of claims 1 to 7, wherein the frame in which the information element is stored is at least one of a Beacon frame, a Probe Request frame, a Probe Response frame, an Association Request frame, an Association Response frame, a ReAssociation Request frame, a ReAssociation Response frame, and an Action frame.

9. The communication device according to claim 1, characterized in that the second Listen mode is capable of performing the Listen operation under conditions that are expected to result in less power consumption than the first Listen mode for at least two of the number of links, bandwidth, number of spatial streams, and Modulation and Coding Scheme (MCS).

10. The communication device according to claim 1, wherein the listen operation includes a carrier sense operation for checking the availability of a wireless channel for which communication is to be attempted.

11. The communication device according to claim 1, characterized in that conditions for at least two or more items of the number of communication links, bandwidth, spatial streams, and MCS in the Listen operation are set based on notifications from other devices.

12. The communication device according to claim 1, wherein the first listen mode is a mode in which the listen operation is performed under communication conditions for all numbers of communication links, bandwidths, numbers of spatial streams, and MCSs that the communication device can communicate with.

13. A wireless communication device characterized by having a transmission control means for controlling the transmission of a frame to another communication device, the frame including an information element indicating whether or not the device supports a second mode, which is a mode for reducing power consumption in a communication standby state compared to power consumption in a communication standby state in a first mode, and which enables communication standby in a state that is expected to consume less power than the first mode in terms of Modulation and Coding Scheme (MCS).

14. A communications device that performs wireless communications compliant with the IEEE 802.11 standard series, comprising: a listen mode for suppressing power consumption when performing a listen operation, which is an operation of waiting for communication, compared to power consumption when performing the listen operation in a first listen mode; a transmission control means for transmitting a frame that causes a transition to the first listen mode to another communications device that is operating in a second mode capable of performing the listen operation by changing at least one of the conditions of the number of communication links, bandwidth, spatial streams, and Modulation and Coding Scheme (MCS) to a condition that is expected to consume less power than in the first listen mode; and the transmission control means further transmits information specifying the link to be used in the second listen mode to the other communications device.

15. The communication device according to claim 14, wherein said transmission control means transmits said frame including information indicating two or more conditions of the number of communication links, bandwidth, spatial streams, and MCS.

16. A communication device as described in claim 15, further comprising a determination means for determining the two or more conditions when operating the other communication device in the second listen mode depending on the communication status with the other communication device, and the transmission control means transmits the determined two or more conditions to the other communication device.

17. A control method for a communication device that performs wireless communication compliant with the IEEE 802.11 standard series, comprising a transmission control step of controlling the transmission to another communication device of a frame including an information element that stores information indicating whether a second Listen mode is supported, in which the Listen mode, which is an operation for waiting for communication, is capable of reducing power consumption when performing the Listen operation compared to power consumption when performing the Listen operation in a first Listen mode, and in which at least one of the number of communication links, bandwidth, spatial streams, and Modulation and Coding Scheme (MCS) is expected to consume less power than the first Listen mode.

18. A control method for a communication device that performs wireless communication compliant with the IEEE 802.11 standard series, comprising: a first transmission step of transmitting information to another communication device operating in a second mode capable of performing the listen operation by changing at least one of the conditions of the number of communication links, bandwidth, spatial streams, and Modulation and Coding Scheme (MCS) to a condition that is expected to consume less power than in the first listen mode, in order to reduce the amount of power consumed when the listen operation, which is an operation that waits for communication, is performed compared to the power consumed when the listen operation is performed in a first listen mode; and a second transmission control step of transmitting information that specifies the link to be used in the second listen mode.

19. A program for causing a computer to execute the communication device control method according to claim 17 or 18.

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