Communication device, control method, and program

Abstract

To provide a concrete mechanism for more proactively reducing standby power consumption.SOLUTION: A communication device that performs wireless communication in accordance with the IEEE802.11 standard series, transmits to another communication device a frame including an information element that stores information indicating whether a second mode is supported in which communication is awaited in a state where 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 a 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.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to a communication device for communicating data. [Background technology]

[0002] In recent years, the increase in the amount of data being communicated has led to the development of communication technologies such as wireless LANs (Local Area Networks). 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] Technologies that utilize sleep, intermittent operation, etc. to reduce the power consumption of communication devices are also being considered. For example, Patent Document 1 discloses a procedure for achieving power saving by coordinating in advance between an AP (Access Point) and a STA (Station) the wake-up times of the devices, communicating during the wake-up times, and reducing power consumption at other times.

[0004] The IEEE802.11be standard, which will be the successor to IEEE802.11ax, is currently being developed, and the UHR (Ultra High Reliability) Task Group is also currently studying the specifications for the IEEE802.11bn standard, which will be the successor to IEEE802.11be. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2016-511600 Summary of the Invention [Problem to be solved by the invention]

[0006] The 802.11be standard attempts to improve communication rates compared to previous standards. It also incorporates a multi-link operation (MLO) function that uses multiple communication links for high-speed data transmission and redundant transmission. Communication devices using new functions such as MLO may receive data over multiple links, multiple spatial streams, wide bandwidths, and high MCS (Modulation and Scheme). Therefore, even in idle states waiting for reception, it is generally necessary to control the signal receiving circuitry and antennas so that all signal patterns can be received. These key features of the standard are certainly useful in terms of faster communication speeds and higher reliability, contributing to an improved user experience. However, there is a problem in that the power required for proper operation of communication devices increases not only during communication but also while waiting for communication. Thus, for today's communication devices, even standby power consumption during standby, such as when waiting for reception, is reaching a non-negligible level.

[0007] The present invention has been made in consideration of at least one of the above-mentioned problems. One aspect of the present invention aims to provide a specific mechanism for more actively reducing power consumption during standby. Specifically, a new function is provided for actively reducing power consumption during standby by selectively using an operating 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 operating 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 invention aims to provide a mechanism for appropriately operating the new Low Power Listen function by making it possible to notify in advance whether the function is supported. [Means for solving the problem]

[0008] One aspect of the present invention is a communication device that performs wireless communication in accordance with the IEEE802.11 standard series, and is characterized by having 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 the second mode is supported, is supported 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 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. [Effects of the Invention]

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

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

[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] First Embodiment An example of the configuration of a communication system according to this embodiment is shown in Fig. 1. 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 that comply with 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. IEEE802.11bn, the successor standard to IEEE802.11be, 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. The wireless frame used in this successor standard is also called UHR (Ultra High Reliability) PPDU. 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 renamed once the standard is fully established. Similarly, the name IEEE 802.11bn may be renamed 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. AP 101 and STA 102 can also transmit wireless frames conforming to legacy standards that predate the IEEE 802.11bn standard. Examples of legacy standards include 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 bands 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 bands and may be, for example, 240 MHz or 4 MHz. The IEEE 802.11 series of standards specifies a frequency channel using a 20 MHz bandwidth as the basic channel in frequency bands such as the 2.4 GHz, 5 GHz, and 6 GHz bands. 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, using a channel in combination with an adjacent channel is referred to as channel bonding. 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 channels with a 20 MHz bandwidth uses a 40 MHz bandwidth. The AP 101 is an access point that supports a multi-band function and 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] The STA 102 establishes one or more links between the STA 102 and the AP 101 to communicate data with the AP 101 or another communication device. For example, the STA 102 executes a connection procedure with the AP 101 to establish a link with the AP 101. When the connection procedure between the STA 102 and the AP 101 is completed, a link is established between the devices. By establishing the link, the communication device 100 can 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 with it. In parallel with this, the AP 101 and the STA 102 can establish a second link, for example, in the 5 GHz band, and communicate with it. In this case, the STA 102 performs multi-link communication, utilizing two links. The STA 102 can perform simultaneous transmit and receive (STR) operation with the AP 101, which allows simultaneous reception via link 1 and transmission via link 2. In other words, STR communication can be performed. The STA 102 can also perform NSTR operation with the AP 101, which is restricted to either using all links for transmission simultaneously or using 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, if link 1 using a 160 MHz bandwidth and link 2 using an 80 MHz bandwidth are established between devices, communication device 100 will communicate using the channels that make up those links. The link using a 160 MHz bandwidth is formed by bundling eight channels with a bandwidth of 20 MHz. The link using an 80 MHz bandwidth is formed 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, they can perform SU-MIMO (Single User Multi-Input Multi-Output) communication using 2SS or 4SS. They can also perform MU-MIMO (Multi-User Multi-Input Multi-Output) communication using 2SS to 16SS. 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 improve reliability. Furthermore, in terms of modulation, they can communicate using BPSK, QPSK, 16QAM, 64QAM, 256QAM, 1024QAM, 4096QAM, etc. to transmit information at a higher density. MCS (Modulation and Coding Scheme) indicates the combination of a modulation method and a modulation scheme such as a code rate as an index, and the communication device 100 can select one of MCSs from MCS0 to MCS15 to communicate.

[0021] As described above, communication devices such as STA102 communicate via multiple links using the MLO function described above, and receive data with the multiple spatial streams, wide bandwidth, and high MCS described above. Therefore, it is generally necessary to control the signal receiving circuit and antenna so that all signal 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, contributing to an improved user experience. However, there is also the problem that the power required for proper operation of communication devices increases not only during communication but also in an idle state waiting for communication to begin. As such, in today's communication devices, even the standby power consumed 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 that 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 is enabled and actively reduces power consumption during standby. Communication devices such as the AP 101 and the STA 102 operate in one of multiple operation modes, including at least the above two operation modes. In this embodiment, Active Mode is also referred to as LPL Disabled Mode or LPL Disabled State. 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. Communication devices such as the STA 102 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 operation modes, the communication device such as the STA 102 notifies the AP 101 or other device of the mode switch. The notification can be made using an Action frame.

[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 the STA 102 operating in the NPCS operating state 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 STA 102 transitions its operating state to the 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 frame indicating the end of a transmission opportunity. The LPCS is an operating state that is expected to reduce power consumption. When transitioning to the LPCS operating state, the communication device such as the STA 102 switches its operating settings to a communication condition customized to reduce power consumption related to communication standby, such as one link, one spatial stream, a 20 MHz bandwidth, and a low MCS. In this embodiment, the state in which two-way communication is being performed or is possible in the LPCS is also referred to as the Low Power Awake state because of its characteristic of being able to maintain a state in which two-way communication is being performed with low power consumption. In other words, the Low Power Awake state can be said to be a state in which the STA 102 operates with lower power consumption than a state in which two-way communication is being performed or is possible in the Active Mode or NPCS operating state. In this embodiment, the communication conditions with restrictions when operating in LPCS are also referred to as LowCapability. Also, the normal communication conditions when operating in NPCS in Active Mode or LPL Enabled Mode are also referred to as HighCapability. LPL Enabled Mode can be considered a mode that is estimated to consume less average power than Active Mode.

[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, the opposing communication device, conveying that it wishes to communicate in a normal state.

[0027] In this way, a communication device such as STA 102 operating in LPL Enabled Mode selectively uses NPCS and LPCS as its operating states. For example, during normal operation, it transitions to NPCS to enable high-speed communication, and during standby, it transitions to LPCS to reduce power consumption. STAs operating in LPL Enabled Mode can achieve both convenience and power savings by selectively using these operating states.

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

[0029] In summary, the LPL Enabled Mode, in which the LPL function of this embodiment is enabled, is 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 is a mode with high communication convenience, as it allows small data communications to be performed at any time.

[0030] A specific mechanism for switching the above modes will be described in detail using Figure 2 and subsequent figures. Note that, 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. In addition, 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, or Bluetooth (registered trademark) LE (Low Energy). 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] <Hardware configuration of communication device> 2 shows an example of the hardware configuration of a 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 a ROM and / or a 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, in addition to memories such as ROM and RAM, the storage unit 201 may also use storage media such as non-volatile storage devices such as hard disks and solid state drives (SSDs).

[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 processing, such as capturing images, printing, and projection. The functional unit 203 is hardware that enables the device to perform predetermined processing. 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 prints on a sheet such as paper based on print data obtained from an external device via wireless communication. For example, if the communication device is a projector or smart glasses, the functional unit 203 is a projection unit that projects image data or video data obtained from an external device 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 the AP 101 can also provide network storage functions such as a network-attached storage (NAS). 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 an AP 101 or the like 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 PPDUs 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 the number of antennas may be greater or less than three.

[0039] If the communication device is compatible with the 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 be capable of individual power control. Alternatively, each link may be configured to have its own communication unit.

[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 piece of hardware to control the operation mode described above and control the connection with the opposing device. Specifically, the connection process involves authentication, association, and 4-way handshake processes 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 the 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 connection procedures 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, F1S (Fast Initial Link Setup), Discovery, and Action. Also included are Authentication Request and Authentication Response frames. Also included are ReAssociation Request and ReAssociation Response. The processing unit 301 also generates and analyzes other management frames of the IEEE 802.11 standard series, as appropriate, but a description of these will be omitted due to space limitations.

[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 a peer 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 of standards. It can also generate UHR Protected action frames related to the LPL function.

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

[0045] The frame transceiver 304 performs the transmission process of the wireless frame generated by the frame processing unit 301 and the reception process of the wireless frame from the counterpart device. The received digital data obtained by the reception process is transferred to the processing unit 301. The processing unit 301 analyzes the received digital data transferred from the transceiver 304, and according to the analysis result, generates an appropriate response frame or notifies the upper layer (not shown) of the analyzed data (such as IP data included in the payload). The frame transceiver 304 performs transmission control to transmit the frame in cooperation with each unit, and reception control to receive the frame.

[0046] The UI (User Interface) control unit 305 provides a setting screen as a UI for the user to input settings related to communication. Also, the UI control unit 305 receives user operations on the setting screen via the input unit 204, and stores the settings as operation settings of the communication device in the storage unit 201. The UI control unit 305 receives a setting change operation to enable or disable the LPL function via a setting screen (not shown). Also, it stores the user setting to enable or disable the LPL function corresponding to the setting change operation in the storage unit 201. The operation settings are appropriately referred to in the flowchart described later.

[0047] <Execution Procedure of LPL> Subsequently, the procedure of 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 execution procedure of the LPL function performed between the AP 101 and the STA 102.

[0048] First, the STA 102 performs connection processing with the AP 101 (F401). The connection processing will 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. By receiving the Beacon or FILS Discovery, the STA 102 recognizes APs such as the AP 101 present in the vicinity 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 an SSID (Service Set Identifier) ​​or a passphrase registered in advance by a user or the like. To connect to the AP 101, the STA 102 first transmits a Probe Request frame to the AP 101. Upon receiving the Probe Request, the AP 101 transmits a Probe Response frame addressed to the STA 102. When connecting via Multi-Link, the Probe Request and Probe Response may be sent and received separately as ML Probe Request and ML Probe Response. When STA102 receives the Probe Response, it sends an Authentication Request frame to AP101. When AP101 receives the Authentication Request frame, it sends an Authentication Response frame to STA102. Each Authentication frame may be sent and received twice. When STA102 receives the Authentication Response frame, it sends an Association Request frame. When AP101 receives the Association Request frame, it sends an Association Response frame. Through these steps, a connection procedure is executed between AP101 and STA102, and a link is established between AP101 and STA102 using a wireless medium.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 the 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 they 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] A specific example of capability information exchanged during the wireless connection procedure will be described with reference to Fig. 5. As an example, capability information is transmitted to the other device using the UHR Capabilities element shown in Fig. 5(A). Fig. 5 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 may also include 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 combination of the Element ID field 501 and the Extended Element ID field 503 indicates the type of element. 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. 5. 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 indicate that the Low Power Listen function is not supported or that the function is disabled. In other words, it can also be modified to indicate a disabled state.

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

[0056] FIG. 5(B) is a modified example of the UHR Capabilities field. The difference from FIG. 5(A) is that the LPL capability information is subdivided into an LPL Tx Support field 514 indicating transmission capability and an LPL Rx Support field 515 indicating reception capability. An 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 an AP to 1 means that the AP supports control of transmitting an ICF with the number of streams / MCS / number of 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. STAs such as STA 102 must also set the LPL Rx Support field 515 to 1. APs such as AP 101 may also 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 procedure described above.

[0059] The AP 101 and the STA 102 enable or disable the LPL function based on the communication status and the capability information indicating whether they support the LPL function that they notify or acquire from each other. In other words, they switch their operation mode to the Active Mode or the LPL Enabled Mode, as 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, in this embodiment, it is assumed 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 the 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 the operating parameters that a STA operating in the LPL Enabled Mode should use to the STA in advance using the UHR Operation element shown in FIG.

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

[0063] By including the elements shown in Fig. 6 in a frame used for wireless connection procedures, AP 101 transmits to opposing devices such as STA 102 two or more communication conditions to be used when operating in an operating state such as LPCS. 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 configured to 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 also 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 elements. Therefore, a value different from the combination of 501 and 503 in FIG. 5 described above 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 that the STA should support when operating in LPCS. For example, an upper limit value indicating that only MCSs up to QAMs lower than the QAMs (e.g., 4096-QAM) that can be used when operating in NPCS (e.g., 16-QAM, 64-QAM, 256-QAM, etc.) are supported is stored. More specifically, this field can hold an index value corresponding to the upper limit of the UHR-MCS that is expected to be used when operating in LPCS. For example, if "7" is stored, the upper limit of the usable MCS is 64-QAM with a coding rate of 5 / 6. In other words, if "7" is stored, the UHR-MCS that can be used when operating in LPCS is limited to MCSs indicated by any of the index values ​​0 to 6.

[0067] The Listen Link field 606 is a field for storing 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-efficient reception standby. These fields are provided from the AP to the STA when optional control is performed to further reduce power consumption by providing Low Power Awake and Doze states within the LPCS operating state. The Listen Interval field 607 indicates the interval at which the STA enters the Low Power Awake state, allowing communication at low power while operating in LPCS. For example, if the value is set to 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, if the value is set to 15, 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, if the value is set to 20, it indicates the initial time of the loop in which the STA enters the Low Power Awake state 20 ms after beacon transmission. Based on these parameters, STAs such as STA102 determine the time to enter Awake and the time to enter Doze, and control switching between Awake operation, which waits for communication in Low Capability, and Doze state based on the determined time. Therefore, even in the NPCS operating state, Doze operation can be performed for a certain period, enabling more adaptive power saving control. Note that 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. The STA 102 transmits a frame for enabling the LPL to the AP 101. The AP 101 receives the frame and transmits a response frame. The STA 102 receives the response frame and transitions its operating mode to the LPL Enabled Mode. Note that, in this embodiment, a case where the STA 102 transitions to the above-mentioned LPCS operating 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 the Action field of an Action frame that notifies the enabling / disabling of Low Power Listen. In this embodiment, this field is referred to as the 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. The Low Power Listen Mode Notification frame Action field may also 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 the Protected UHR Action. The Protected UHR Action field 702 indicates an 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 Dialog 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 Dialog Token field 703. The responding communication device stores the value contained in the received Dialog Token field 703 in the Dialog Token field 703 of a response frame and transmits the response frame. In addition, a 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 the LPL function is to be used. For example, when the STA 102 requests that it start using the Low Power Listen function, it stores a 1 in this field. On the other hand, when the STA 102 requests that it stop using the LPL function, it stores a 0 in this field. The LPL Mode field 711 may be configured to have two bits so that it can indicate whether or not it will be used for transmission and reception, respectively. For example, when the STA 102 specifies a 0 in the first bit and a 1 in the second bit, the STA 102 requests that it will use the reception process during LPCS, but not the transmission process during LPCS.

[0072] The Low Power Listen Parameter Update Control field 712 indicates whether or not the Low Power Listen Parameter Update field 705 is present. For example, if the Low Power Listen Mode Notification frame Action field includes the Low Power Listen Parameter Update field 705, 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, a 0 is stored in this field. The Low Power Listen Parameter Update field 705 includes the Padding Delay field 604, the MCS field 605, the Listen Link field 606, the Listen Interval field 607, the Listen duration field 608, and the Listen offset field 609. These fields have the same functions as the fields with the same names described in FIG. 6, so their description 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 the bandwidth to be used. When a STA, such as the STA 102, wishes 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, that is the peer 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 AP 101 has accepted the request to use the LPL function. If the request is accepted by the AP 101, the STA 102 changes its 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 communication parameters to those corresponding to the LPCS. Specifically, if the STA 102 communicates updated communication parameter information using the Enabling sequence frame illustrated in F402, the STA 102 sets the communication parameters. On the other hand, if the Enabling sequence does not communicate updated communication parameter information, the STA 102 sets the communication parameters for the LPCS that were previously shared by the AP 101 using the UHR Operation element. The STA 102 then begins waiting for frames using the LPCS.

[0075] Next, the 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 where it can receive frames with the parameters described in the Link Info List field while waiting for reception for the period described in this field. The RA field 803 stores the MAC address of the STA 102, which indicates the recipient 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 for identifying a link to be used in the NPCS state and one or more pieces of correspondence information that combine communication parameters for the link. When operating an STA in the NPCS operating state and enabling multiple links, 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 for identifying a link to be used in NPCS. Furthermore, fields 812 to 815 indicate communication parameters to be used when communicating over the link identified in 805. The following will be explained in detail. 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 by 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 before transmitting frames 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, an ICF may be simultaneously transmitted on a different link that is expected to be used for communication after transitioning to NPCS in order to secure transmission rights on that link.

[0077] Next, a response frame to an ICF will be described with reference to 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 their descriptions will be omitted. The Status Code field 901 indicates whether communication is possible with the value specified in the ICF. Note that the transmission of the ICF Response frame can also be omitted. Alternatively, a configuration may be adopted in which a CTS (Clear To Send) frame is returned instead of the ICF Response frame shown in FIG. 9. In this case, the CTS frame may be returned every 20 MHz across all links and bandwidths specified in the ICF.

[0078] Next, STA 102 starts frame waiting processing in NPCS. Specifically, STA 102 updates its own communication parameters with the communication parameters included in ICF and starts waiting for frames with the communication parameters corresponding to hissu. In other words, STA 102 switches to a communication condition of HighCapability 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 is complete, it transmits a CF-End frame or a QoS Null frame (F407). This frame functions as a frame that ends the NPCS operating 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 operating state back to LPCS. In other words, the STA 102 switches to a LowCapability communication condition, which intentionally limits functionality for power saving.

[0082] Note that, in FIG. 4, the case where downlink communication is performed using the ICF issued by AP101 as a trigger is illustrated. On the other hand, in STA102, when uplink data is generated or when STA102 determines that it desires to perform high-speed communication and / or highly reliable communication spontaneously, it may determine the communication conditions corresponding to NPCS by itself and transition to NPCS. STA102 that has transitioned to NPCS performs CCS (Clear Channel Assessment) with transmission parameters corresponding to the updated communication conditions, and transmits a CTS frame when it determines that it has won channel access. Then, when it can receive an RTS (Request To Send) frame from AP101 for the CTS frame, it may be configured to transmit a data frame. STA102 that determines that it should switch the operation mode to LPCS after finishing a series of data transmissions transmits a CF-End frame. Note that, instead of the CF-End frame, a QoS Null frame or a QoS data frame in which 0 is set in the RDG / More PPDU subfield of the CAS Control field may be transmitted. According to the transmission of the frame, STA102 transitions its operation state to LPCS. That is, STA102 intentionally switches to a LowCapability communication condition with restricted functions.

[0083] Although omitted in FIG. 4 for reasons of space, STA102 that determines that it should change the operation mode to Active Mode according to the communication situation or the like transmits a request to disable LPL to AP101. AP101 that has received the request transmits a response frame indicating that it has accepted the disabling of LPL. In these LPL Disabling sequences, the disabling may be requested using the LPL Operating Mode Notification frame described with reference to FIG. 7. When requesting the disabling, STA102 stores 0 in the LPL Mode field included in the frame and requests the disabling.

[0084] <Communication Control Utilizing LPL Function> Next, communication control utilizing 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 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 described as the subject. Note that the control indicated by the dotted lines is optional control, and it is not necessarily required to execute that control.

[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 in cooperation with the various processors, ASICs, DSPs, and FPGAs that constitute the communication unit 206, and the ASICs, DSPs, and FPGAs that constitute the control unit 202. Note that this is not a limitation, and it is of course possible to configure the communication unit 206 and the antenna to cooperate to execute each process shown in the flowchart. Note that when it is desired to clearly indicate the subject of the process, the functional unit described in FIG. 3 will be used as the subject in the description. Note that the control indicated by the dotted lines is optional and does not necessarily have 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 AP 101 to when it decides whether to use the LPL mode. Fig. 12 shows an excerpt of the specific processes when it is decided to use 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 also performs the connection process shown in FIG. 4 and completes 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. In other words, the STA 102 starts operation with communication parameters that enable high-speed communication and / or highly reliable communication, corresponding to the HighCapability 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 set to disable the LPL function. If it is determined that the user setting has been set 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 set to disable the LPL function, the process proceeds to S1003.

[0092] In S1003, mode control unit 302 determines whether the destination AP to which STA 102 is connected supports the LPL function. Specifically, in S1001, if 1 is specified in LPL Support field 504 of the capability information acquired from the destination AP, it is determined that the LPL function is supported. As another example, if 1 is specified in LPL Tx Support field 514 of the acquired capability information, it is determined that the LPL function is supported. 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, and 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 link 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 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 the 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. If it is determined that the communication quality with the AP 101 is equal to or lower than a predetermined threshold, the process proceeds to S1009, and if it is determined that the communication quality with the AP 101 is higher than the predetermined threshold, 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, and if it is not determined that data transmission to the STA of the NPCS is necessary, the process proceeds to S1107.

[0100] In S1101, frame processing unit 301 identifies the traffic type required for data transmission to the destination STA determined to require data transmission in S1100 and estimates the traffic volume. For example, processing unit 301 identifies the traffic type into which the data is classified based on the QoS information of the data. Also, for example, processing unit 301 stores past communication records and the like, and estimates the traffic volume, which is a characteristic of the traffic to be generated, by comparing the communication records with the characteristics of the data to be transmitted (for example, data source information / destination information, etc.). 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 a transition to the NPCS should be made), 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, in cooperation with the RX / TX control unit 303, sets communication parameters for LPCS corresponding to the destination STA as transmission parameters for the communication unit 206 and the antenna 207. Next, the processing unit 301, in cooperation with the transceiver unit 304, the communication unit 206, and the antenna 207, transmits data using the communication parameters for LPCS. 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 various 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 manages the determined communication parameters and operation state as current state information associated with the destination STA. In other words, the control unit 302 updates the operation 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. Then, the processing unit 301 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 transceiver 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 is complete based on the data accumulation status in the transmission buffer, etc., it 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 AP and the STA. Specifically, when the control unit 302 receives an LPL Operating Mode Notification frame in cooperation with each unit, it determines whether enabling / disabling of the LPL is necessary. The control unit 302 also determines whether enabling / disabling of the LPL is necessary for a specific STA based on the communication status. For example, it can determine that enabling of the LPL is necessary for an Active Mode STA whose data transmission frequency has decreased. It can also determine that disabling of the LPL is necessary for an LPL Enabled Mode STA that has generated a large amount of downlink data or low-latency data. This means that the AP determines that the operating mode should be changed for a specific STA that is not or is estimated to become incompatible with the current operating mode based on the communication status known to the AP.

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

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

[0109] 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 controls. 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, an STA whose operating state is LPCS may spontaneously transition to an NPCS operating state and perform data communication with the AP using communication parameters corresponding to HighCapability. When the control unit 302 receives data using communication parameters corresponding to HighCapability from a STA whose state information currently managed is LPCS, it updates the operating state of the STA that is the source of the data. That is, it updates the operating state included in the state information of the STA that is currently managed 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 frame transmission / reception unit 304. Specifically, it 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, communication unit 206, and antenna 207. If the LPL Operating Mode Notification frame includes field 705, the transmission and reception parameters are changed to those corresponding to the parameters indicated in field 705. If the LPL Operating Mode Notification frame does not include field 705, the transmission and reception parameters are changed to those shared in advance by the destination AP, such as 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, and if it is not determined that data transmission to the AP is 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 control on the AP side, 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 the communication rate for communication while maintaining the LPCS will fit within a predetermined time. If it is determined that the transmission time will fit within the predetermined time, it determines that the estimated traffic should be communicated while maintaining the LPCS of the destination STA.

[0119] In S1206, the control unit 202 cooperates with each unit to execute data communication using communication parameters for LPCS. In the case of data reception processing, the control unit 202 receives frames using the set reception parameters for LPCS, 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 reception parameters for LPCS. 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 HighCapability 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 determination is made based on a determination similar to that described in S1005 to S1008 above. That is, if any of the following conditions is met: the remaining battery charge has dropped below a threshold, the communication link has been re-set up as an NSTR link pair, or the communication quality is below a predetermined threshold, the mode control unit 302 determines that disabling is necessary. The mode control unit 302 also determines that disabling is necessary if a low-latency communication application is running. The mode control unit 302 also determines that disabling is necessary based on a determination similar to that described in S1002, that is, if 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. Next, the mode control unit 302 changes the communication parameters for transmission and reception to communication parameters corresponding to HighCapability 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 in the connection process.

[0125] <Variation 1> In the above-described embodiment, 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 other parameters used in the LPCS operating state. However, this is not limiting. It is also possible to notify only information identifying the link corresponding to 606, and use predefined communication parameters for other communication parameters. Predefined communication parameters can be, for example, communication parameters that use one spatial stream, the minimum MCS required to receive control frames such as ICF, and only the primary 20 MHz bandwidth. A specific example is described below. STA 102 operates as a non-AP MLD and performs multi-link communication established with AP 101 in Active Mode. One of these links also utilizes MIMO communication, and communication with a high MCS and a 160 MHz bandwidth is also possible. In this state, upon receiving an LPL Operating Mode Notification, STA 102 changes its condition to one that allows communication with a 20 MHz bandwidth over a single link identified by the link ID. Furthermore, it changes its condition to one that does not use MIMO or the like and uses a single number of spatial streams.

[0126] <Variation 2> In the above embodiment, the ICF frame includes communication parameters to be used after transitioning to 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 NPCS. For example, the default communication parameters may be the communication parameters used when operating in Active Mode negotiated during connection processing.

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

[0128] <Other 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, A communication device characterized by having 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 a second mode in which communication is awaited 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 consumption when awaiting communication compared to the power consumption when awaiting communication in the first mode.

[0130] (Configuration 2) 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.

[0131] (Configuration 3) 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 transmission control means transmits the frame in which information indicating that the second mode is supported is stored in the information element; a transition means for, after establishing a link for communication with another communication device, when the other communication device is operating in the first mode, changing the two or more conditions to conditions estimated to consume less power than the first mode and transitioning the operation mode of the communication device to the second mode after transmitting information regarding activation to the other communication device regarding activation to the second mode; 4. The communication device according to any one of configurations 1 to 3, comprising:

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

[0134] (Configuration 6) 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 described in any one of configurations 1 to 6, characterized in that 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) 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, a transmission control means for transmitting a frame to cause another communication device operating in a second mode to wait for communication, the second mode being a state 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; The communication device is characterized in that the transmission control means further transmits information specifying a link to be used in the second mode to the other communication device.

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

[0139] (Configuration 11) a determining unit for determining the two or more conditions for operating the other communication device in the second mode according to a communication status with the other communication device; 11. The communication device according to configuration 10, wherein the transmission control means transmits the determined two or more conditions to the other communication device.

[0140] (Configuration 12) A method for controlling a communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, comprising: A control method for a communication device, comprising a transmission control step of controlling the transmission of a frame to another communication device, the frame including an information element storing information indicating whether a second mode 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 consumption when waiting for communication compared to the power consumption when waiting for communication in the first mode.

[0141] (Configuration 13) A method for controlling a communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, comprising: A control method for a communication device, comprising a first transmission control step of transmitting information to another communication device operating in a 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 in the first mode in order to reduce the amount of power consumed when waiting for communication compared to the power consumed when waiting for communication in the first mode, the first transmission control step comprising transmitting information to cause a transition to the second mode and information identifying the link to be used in the second mode.

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

[0143] <Other embodiment 2> The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more 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. [Explanation of symbols]

[0145] 101 AP MLD 102 non-AP MLD 206 Communications Department

Claims

1. A communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, A communication device characterized by having 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 power consumption when waiting for communication in the first mode.

2. 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. 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 at least an Association Request frame and transmitting the frame.

4. the transmission control means transmits the frame in which information indicating that the second mode is supported is stored in the information element; a transition means for, after establishing a link for communication with another communication device, when the other communication device is operating in the first mode, changing the two or more conditions to conditions estimated to consume less power than the first mode after transmitting information regarding the activation of the second mode to the other communication device, and transitioning the operation mode of the communication device to the second mode; 2. The communication device according to claim 1, further comprising:

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

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

7. 2. The communication device according to claim 1, 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.

8. 8. The communication device according to claim 1, 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. A communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, a transmission control means for transmitting a frame to cause another communication device operating in a second mode to wait for communication, the second mode being a standby 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; The communication device is characterized in that the transmission control means further transmits information specifying a link to be used in the second mode to the other communication device.

10. 10. The communication device according to claim 9, wherein said transmission control means transmits said frame including information indicating said two or more conditions.

11. a determining unit for determining the two or more conditions for operating the other communication device in the second mode according to a communication status with the other communication device; 11. The communication device according to claim 10, wherein the transmission control means transmits the determined two or more conditions to the other communication device.

12. A method for controlling a communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, comprising: A control method for a communication device, characterized by comprising a transmission control step of controlling the transmission of a frame to another communication device, the frame including an information element storing information indicating whether a second mode in which communication is awaited 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 consumption when awaiting communication compared to the power consumption when awaiting communication in the first mode.

13. A method for controlling a communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, comprising: A control method for a communication device, characterized by comprising a first transmission control step of transmitting information to another communication device operating in a second mode awaiting communication, the second mode being 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 power consumption when awaiting communication in a first mode, to cause the device to transition to the second mode and information identifying the link to be used in the second mode.

14. A program for causing a computer to execute the method for controlling a communication device according to claim 12 or 13.

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